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  • C12N2830/001—Vector systems having a special element relevant for transcription controllable enhancer/promoter combination
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  • C12N2830/80—Vector systems having a special element relevant for transcription from vertebrates
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Definitions

• This invention relates to cell transfection using adenovirus vectors, providing replication-competent adenovirus vectors and methods of their use. More specifically, it relates to cell-specific replication of adenovirus vectors in cells through the use of cell- specific, non-adenoviral transcriptional regulatory elements.
• Neoplasia resulting in benign tumors can usually be completely cured by removing the mass surgically. If a tumor becomes malignant, as manifested by invasion of surrounding tissue, it becomes much more difficult to eradicate. Once a malignant tumor metastasizes, it is much less likely to be eradicated.
• Hepatocellular carcinoma (HCC or malignant hepatoma) is one of the most common cancers in the world, and is especially problematic in Asia. Treatment prospects for patients with hepatocellular carcinoma are dim. Even with improvements in therapy and availability of liver transplant, only a minority of patients are cured by removal of the tumor either by resection or transplantation. For the majority of patients, the current treatments remain unsatisfactory, and the prognosis is poor.
• Breast cancer is one of the most common cancers in the United States, with an annual incidence of about 182,000 new cases and nearly 50,000 deaths. In the industrial countries, approximately one in eight women can expect to develop breast cancer. The mortality rate for breast cancer has remained unchanged since 1930. It has increased an average of 0.2% per year, but decreased in women under 65 years of age by an average of 0.3% per year. See e.g., Marchant (1994) Contemporary Management of Breast Disease II: Breast Cancer, in: Obstetrics and Gynecology Clinics of North America 21:555-560; and Colditz (1993) Cancer Suppl. 71 :1480-1489. Despite ongoing improvement in the understanding of the disease, breast cancer has remained resistant to medical intervention.
• Prostate cancer is the fastest growing neoplasm in men with an estimated 244,000 new cases in the United States being diagnosed in 1995, of which approximately 44,000 deaths will result. Prostate cancer is now the most frequently diagnosed cancer in men. Prostate cancer is latent; many men carry prostate cancer cells without overt signs of disease. It is associated with a high morbidity. Cancer metastasis to bone (late stage) is common and is almost always fatal.
• a major, indeed the overwhelming, obstacle to cancer therapy is the problem of selectivity; that is, the ability to inhibit the multiplication of tumor cells, while leaving unaffected the function of normal cells.
• selectivity that is, the ability to inhibit the multiplication of tumor cells, while leaving unaffected the function of normal cells.
• the therapeutic ratio, or ratio of tumor cell killing to normal cell killing of traditional tumor chemotherapy is only 1.5:1.
• cancer therapy Of particular interest is development of more specific, targeted forms of cancer therapy, especially for cancers that are difficult to treat successfully.
• conventional cancer therapies which result in relatively non-specific and often serious toxicity, more specific treatment modalities attempt to inhibit or kill malignant cells selectively while leaving healthy cells intact.
• a gene of interest is introduced into the malignant cell. See, for gene therapy for prostate cancer, Boulikas (1997) Anticancer Res. 17:1471-1505.
• the gene of interest may encode a protein which converts into a toxic substance upon treatment with another compound, or an enzyme that converts a prodrug to a drug.
• introduction of the herpes simplex gene encoding thymidine kinase (HSV-tk) renders cells conditionally sensitive to ganciclovir.
• HSV-tk thymidine kinase
• the gene of interest may encode a compound that is directly toxic, such as diphtheria toxin.
• the gene of interest can be under control of a transcriptional regulatory element (TRE) that is specifically (i.e., preferentially) activated in the cancer cells.
• TRE transcriptional regulatory element
• Cell or tissue specific expression can be achieved by using a TRE with cell-specific enhancers and/or promoters. See generally Huber et al. (1995) Adv. Drug Delivery Reviews 17:279-292.
• adenovirus A variety of viral and non- viral (e.g., liposomes) vehicles, or vectors, have been developed to transfer these genes.
• viruses proposed for gene transfer adenoviruses are among the most easily produced and purified.
• Adenovirus also has the advantage of effecting high efficiency of transduction and does not require cell proliferation for efficient transduction of cell.
• adenovirus can infect a wide variety of cells in vitro and in vivo.
• adenovirus vectors When used as gene transfer vehicles, adenovirus vectors are often designed to be replication-defective and are thus deliberately engineered to fail to replicate in the target cells of interest.
• the early adenovirus gene products EIA and/or EIB are deleted and provided in trans by the packaging cell line 293.
• the gene to be transduced is commonly inserted into adenovirus in the El A and EIB region of the virus genome. Bett et al. (1994).
• adenoviral vectors for gene therapy The virtually exclusive focus in development of adenoviral vectors for gene therapy is use of adenovirus merely as a vehicle for introducing the gene of interest, not as an effector in itself. Replication of adenovirus has been viewed as an undesirable result, largely due to the host immune response. In the treatment of cancer by replication-defective adenoviruses, the host immune response limits the duration of repeat doses at two levels. First, the capsid proteins of the adenovirus delivery vehicle itself are immunogenic. Second, viral late genes are frequently expressed in transduced cells, eliciting cellular immunity.
• Adenoviruses generally undergo an effective lytic replication cycle following infection of a host cell. In addition to lysing the infected cell, the replicative process of adenovirus blocks the transport and translation host cell mRNA thus inhibiting protein synthesis of the infected cell.
• adenoviruses and adenovirus replication see Shenk, T. and Horwitz, M.S., Virology, third edition, Fields, B.N. et al., eds., Raven Press Limited, New York (1996), Chapters 67 and 68, respectively.
• adenovirus vectors have recently been described as agents for effecting selective cell growth inhibition. See Henderson et al, U.S. Patent No. 5,698,443; Hallenbeck et al., WO 96/17053.
• a cell-specific transcriptional regulatory element controls the expression of a gene essential for viral replication, and thus, viral replication is limited to a cell population in which the TRE is functional.
• an attenuated, replication-competent adenovirus has been generated by inserting the prostate-specific antigen (PSA) promoter and enhancer (PSE-TRE) upstream of the EIA transcription unit in adenovirus serotype 5 (Ad5).
• PSA prostate-specific antigen
• PSE-TRE enhancer
• CN706 demonstrates selective cytotoxicity toward PSA expressing cells in vitro and in vivo.
• the present invention provides an adenovirus vector comprising a first adenovirus gene under transcriptional control of a first heterologous transcriptional regulatory element (TRE) and at least a second gene under transcriptional control of a second heterologous transcriptional regulatory element (TRE)
• TRE transcriptional regulatory element
• the first heterologous TREs is cell-specific, the first heterologous TRE is different from the second heterologous TRE and the heterologous TREs are functional in the same cell.
• the invention provides an adenovirus vector in which the cell specific heterologous TRE controls the transcription of a gene essential for adenovirus replication.
• the invention provides an adenovirus vector in which the second heterologous TRE controls the transcription of a transgene.
• the invention provides adenovirus vector(s) complexed with a hydrophilic polymer ("masking agent") to create a masked adenovirus.
• a hydrophilic polymer is attached (covalently or non-covalently) to the capsid proteins of the adenovirus, particularly the hexon and fiber proteins.
• the adenovirus vectors of the instant invention are complexed with masking agents to create masked adenovirus vectors.
• the masking agent is polyethyleneglycol (PEG) covalently linked to an adenovirus vector of the instant invention.
• the invention further provides host cells containing the adenovirus vectors of the invention.
• adenoviral vectors of the invention methods of using the adenoviral vectors of the invention.
• methods for using the adenovirus vectors described herein which entail introducing these vector(s) into a cell.
• methods are provided for conferring selective cytoxicity on a cell which allows the heterologous TREs to function that entail contacting the cells with an adenovirus vector described herein, wherein the adenovirus vector enters the cell.
• methods are provided for suppressing tumor growth, comprising contacting a target cell with an adenovirus vector described herein such that the adenovirus vector enters the cell.
• methods are provided for modifying the genotype of a target cell, comprising contacting the cell with an adenovirus vector described herein, wherein the adenovirus vector enters the cell.
• methods for propagating the adenovirus vectors of the invention, comprising combining the adenovirus vectors with cells which allow the heterologous TREs to function, such that the adenovirus vector enters the cell and is propagated.
• Figure 1 depicts schematic diagrams of examples of adenovirus vectors in which various genes are under transcriptional control of various heterologous TREs.
• the heterologous TREs contained in an adenovirus vector are different from each other and from the endogenous adenovirus TREs. All of the heterologous TREs in an adenovirus vector are functional in the same cell and at least one of the TREs is cell specific.
• Figure 2 (A)-(C) are schematic diagrams of examples of adenovirus vectors in which the El A and EIB genes are under transcriptional control of prostate cell specific heterologous TREs.
• CN702 is an example of a wild-type Adenovirus type 5 and CN706 contains a single gene (EIA) under control of a single prostate cell specific TRE, one derived from the PSA gene.
• Figure 3 shows the cytopathic effects of CN702 and CN764 at various multiplicities of infection on human microvascular endothelial cells.
• Figure 4 is a bar graph showing the number of plaque-forming units, expressed as percentage of plaques obtained with wild-type adenovirus, obtained when either LNCaP cells (hatched bars) or HMVEC cells (bars with square pattern) were infected with adenoviral vectors CN739, CN764, CN765 or CN770.
• Figure 5 is a line graph illustrating the one-step growth curve of an adenovirus, CN739, in which multiple adenoviral early genes are placed under control of prostate cell specific heterologous TREs, in prostate (LNCaP) and non-prostate cells (HMVEC).
• LNCaP prostate cell specific heterologous TREs
• HMVEC non-prostate cells
• Figure 6 is a line graph illustrating the efficacy in treating a prostate cancer tumor in mice of an adenovirus, CN739, in which multiple adenoviral early genes are placed under control of prostate cell specific heterologous TREs.
• Figure 7 is a line graph showing serum PSA levels in mice treated with an adenovirus, CN739, in which multiple adenoviral early genes are placed under control of prostate cell specific heterologous TREs.
• FIGS. 8 (A)-(B) are schematic diagrams of examples of adenovirus vectors in which the EIA and EIB genes are under transcriptional control of cell specific heterologous TREs.
• Each adenovirus vector contains at least two different heterologous TREs, both of which are functional in the same cell.
• Figure 9 depicts schematic diagrams of examples of adenovirus vectors in which the EIA, EIB, and E4 genes are under transcriptional control of cell specific heterologous TREs.
• Each adenovirus vector contains three different heterologous TREs, all of which are functional in the same cell.
• Figure 10 is a graph depicting cytotoxicity of an adenoviral vector containing the coding sequence for adenoviral death protein (ADP), CN751 (solid squares), compared to control CN702 (solid circles), Rec 700 (solid triangles) and mock infection (Xs).
• Figure 11 is a graph comparing extracellular virus yield of CN751 (solid squares) and CN702 (solid circles).
• Figure 12 is a graph comparing tumor volume in mice harboring LNCaP tumor xenografts challenged with CN751 ("H"), CN702 ("J”), or buffer (“B”).
• Figure 13 is a schematic depiction of a method for covalent pegylation of an adenovirus.
• succinimidyl succinamide is used to covalently attach methoxy-PEG to adenovirus.
• the pegylated adenovirus is separated from the reaction components by ion exchange chromatography.
• Figure 14 shows a half-tone reproduction of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel (mobility shift) of pegylated adenovirus proteins.
• Lanes 1 and 2 are non-pegylated CN706 (control)
• lanes 3 through 6 are CN706 pegylated under various pH and temperature conditions (lane 3, pH 7.6, room temperature (RT); lane 4, pH 7.6, 4°C; lane 5, pH 8.2, RT; lane 6, pH 8.2, 4°C).
• Figure 15 is a chromatogram of ion exchange chromatography analysis of pegylated adenovirus (PEG-706) mixed with control adenovirus CN706.
• the adenovirus vectors of this invention comprise a first adenovirus gene under the transcriptional control of a cell-specific heterologous TRE and at least one other gene, such as an adenoviral gene or a transgene, under control of another heterologous TRE which is different from the first TRE, where the heterologous TREs are functional in the same cell but are not the same in polynucleotide sequence (i.e., have different polynucleotide sequences).
• at least two of the heterologous TREs in an adenovirus vector are cell specific for the same cell.
• the adenovirus gene is one that enhances cell death, more preferably one that is essential for adenovirus replication.
• At least one of the adenovirus genes necessary for cell replication is an early gene.
• the genes under transcriptional control of the heterologous TREs are necessary for replication.
• the adenovirus vectors of the invention replicate preferentially in TRE functional cells (i.e., at a higher yield than in TRE non-functional cells). This replication preference is indicated by comparing the level of replication (i.e., titer) in cells in which the TRE is active to the level of replication in cells in which the TRE is not active. The replication preference is even more significant, as the adenovirus vectors of the invention actually replicate at a significantly lower rate in TRE non-functional cells than wild type virus.
• Comparison of the adenovirus titer of a TRE active cell type to the titer of a TRE inactive cell type provides a key indication that the overall replication preference is enhanced due to the replication in TRE active cells as well as depressed replication in TRE inactive cells. This is especially useful in the cancer context, in which targeted cell killing is desirable.
• adenovirus vectors of this invention are more stable and provide even more cell specificity with regard to replication than previously described adenovirus vectors.
• Adenovirus vectors have been constructed in which each of the EIA and EIB genes have been placed under transcriptional control of two different heterologous TREs, for example, TREs from the
• PSA gene PSE-TRE
• PR-TRE probasin gene
• TREs from the PSA gene and the hKLK2 gene hKLK2-TKE.
• adenoviruses containing the RSE-TRE and the RR-TRE and adenovirus containing the RSE-TRE and the hKLK2- ⁇ KE appear to possess a stable genome, exhibit higher levels of cell specificity with regard to replication than CN706, an adenovirus with the RSE-TRE controlling the El A gene, and replicate as efficiently as CN706 in prostate cells.
• CN739 adenovirus with a RR-TRE controlling the El A gene and a RSE-TRE controlling the EIB gene, described below
• CN764 adenovirus with a RSE-TRE controlling the El A gene and an hKLK2-TRE controlling the EIB gene, described below
• this invention provides an even more attenuated replication competent virus by controlling replication genes with two different heterologous, cell-specific TREs.
• the adenovirus vectors provided by the present invention in which two different heterologous TREs are used to control replication, achieve a stability of the viral genome and an even higher level of target cell specificity than previously described adenoviruses.
• the invention uses and takes advantage of what has been considered an undesirable aspect of adenoviral vectors, namely, their replication and possible concomitant immunogenicity. Runaway infection is prevented due to the cell-specific requirements for viral replication.
• production of adenovirus proteins can serve to activate and/or stimulate the immune system, either generally or specifically toward target cells producing adenoviral proteins which can be an important consideration in the cancer context, where patients are often moderately to severely immunocompromised.
• adenovirus refers to the virus itself or derivatives thereof. The term covers all serotypes and subtypes and both naturally occurring and recombinant forms, except where indicated otherwise.
• polynucleotide refers to a polymeric form of nucleotides of any length, either ribonucleotides or deoxynucleotides. Thus, this term includes single-, double- and triple-stranded DNA, as well as single- and double-stranded RNA, RNA-DNA hybrids, or a polymer comprising purine and pyrimidine bases, or other natural, chemically, biochemically modified, non-natural or derivatized nucleotide bases.
• the backbone of the polynucleotide can comprise sugars and phosphate groups (as may typically be found in RNA or DNA), or modified or substituted sugar or phosphate groups.
• the backbone of the polynucleotide can comprise a polymer of synthetic subunits such as phosphoramidates and thus can be a oligodeoxynucleoside phosphoramidate (P-NH2) or a mixed phosphoramidate- phosphodiester oligomer.
• P-NH2 oligodeoxynucleoside phosphoramidate
• Peyrottes et al. (1996) Nucleic Acids Res. 24: 1841-8; Chaturvedi et al. (1996) Nucleic Acids Res. 24: 2318-23; Schultz et al. (1996) Nucleic Acids Res. 24: 2966-73.
• a phosphorothioate linkage can be used in place of a phosphodiester linkage.
• the polynucleotide is DNA.
• DNA includes not only bases A, T, C, and G, but also includes any of their analogs or modified forms of these bases, such as methylated nucleotides, internucleotide modifications such as uncharged linkages and thioates, use of sugar analogs, and modified and/or alternative backbone structures, such as polyamides.
• a double-stranded polynucleotide can be obtained from the single-stranded polynucleotide product of chemical synthesis either by synthesizing the complementary strand and annealing the strands under appropriate conditions, or by synthesizing the complementary strand de novo using a DNA polymerase with an appropriate primer.
• gene is well understood in the art and is a polynucleotide encoding a polypeptide.
• a gene includes non-coding regions including, but not limited to, introns, transcribed but untranslated segments, and regulatory elements upstream and downstream of the coding segments.
• a "transcriptional regulatory element”, or “TRE” is a polynucleotide sequence, preferably a DNA sequence, that regulates (i.e., controls) transcription of an operably-linked polynucleotide sequence by an RNA polymerase to form RNA.
• a TRE increases transcription of an operably linked polynucleotide sequence in a host cell that allows the TRE to function.
• the TRE comprises an enhancer element and/or promoter element, which may or may not be derived from the same gene.
• the promoter and enhancer components of a TRE may be in any orientation and/or distance from the coding sequence of interest, and comprise multimers of the foregoing, as long as the desired transcriptional activity is obtained.
• a TRE may or may not lack a silencer element.
• an “enhancer” is a term well understood in the art and is a polynucleotide sequence derived from a gene which increases transcription of a gene which is operably- linked to a promoter to an extent which is greater than the transcription activation effected by the promoter itself when operably-linked to the gene, i.e. it increases transcription from the promoter.
• Having “enhancer activity” is a term well understood in the art and means what has been stated, i.e., it increases transcription of a gene which is operably linked to a promoter to an extent which is greater than the increase in transcription effected by the promoter itself when operably linked to the gene, i.e., it increases transcription from the promoter.
• a polynucleotide or polynucleotide region has a certain percentage (for example, 80%), 85%o, 90%), or 95%>) of "sequence identity" to another sequence means that, when aligned, that percentage of bases are the same in comparing the two sequences.
• This alignment and the percent homology or sequence identity can be determined using software programs known in the art, for example those described in Current Protocols in Molecular Biology (F.M. Ausubel et al., eds., 1987) Supplement 30, section 7.7.18, Table 7.7.1.
• a preferred alignment program is ALIGN Plus (Scientific and Educational Software, Pennsylvania).
• a first heterologous TRE is "different” from a second (or another) heterologous TRE when the polynucleotide sequence identity between the two heterologous TREs is less than about 95%>, preferably less than about 90%), preferably less than about 85%, preferably less than about 75%.
• “different TREs” are derived from the transcriptional regulatory regions of different genes.
• “Different TREs” may also be derived from the transcriptional regulatory region of the same gene, as long as the sequence identity between them is less than the values listed above (i.e., less than about 95%o, preferably less than about 90%, preferably less than about 85%, preferably less than about 75%). Although two different TREs are not identical in polynucleotide sequence, they may be functional in the same cell and may also have the same cell-specificity.
• a TRE derived from a specific gene is referred to by the gene from which it was derived and is a polynucleotide sequence which regulates transcription of an operably linked polynucleotide sequence in a host cell that expresses said gene.
• a "human glandular kallikrein transcriptional regulatory element" or "hKLK2-TKE” is a polynucleotide sequence, preferably a DNA sequence, which increases transcription of an operably linked polynucleotide sequence in a host cell that allows an hKLK2-TRE to function, such as a cell (preferably a mammalian cell, even more preferably a human cell) that expresses androgen receptor.
• An hKLK2-TKE is thus responsive to the binding of androgen receptor and comprises at least a portion of an hKLK2 promoter and/or an hKLK2 enhancer (i.e., the ARE or androgen receptor binding site).
• a "probasin (RR) transcriptional regulatory element", or "RR-TRE” is a polynucleotide sequence, preferably a DNA sequence, which selectively increases transcription of an operably-linked polynucleotide sequence in a host cell that allows a RR- TRE to function, such as a cell (preferably a mammalian cell, even more preferably a human cell) that expresses androgen receptor.
• a RR-TRE is thus responsive to the binding of androgen receptor and comprises at least a portion of a RR promoter and/or a RR enhancer (i.e., the ARE or androgen receptor binding site).
• a "prostate-specific antigen (PSA) transcriptional regulatory element” is polynucleotide sequence, preferably a DNA sequence, which selectively increases transcription of an operably linked polynucleotide sequence in a host cell that allows a R&4-TRE to function, such as a cell (preferably a mammalian cell, even more preferably a human cell) that expresses androgen receptor.
• a RSE-TRE is thus responsive to the binding of androgen receptor and comprises at least a portion of a PSA promoter and/or a PSA enhancer (i.e., the ARE or androgen receptor binding site).
• a “carcinoembryonic antigen (CEA) transcriptional regulatory element” is polynucleotide sequence, preferably a DNA sequence, which selectively increases transcription of an operably linked polynucleotide sequence in a host cell that allows a CE4-TRE to function, such as a cell (preferably a mammalian cell, even more preferably a human cell) that expresses CEA.
• the CE-4-TRE is responsive to transcription factors and/or co-factor(s) associated with CEA-producing cells and comprises at least a portion of the CEA promoter and/or enhancer.
• an " ⁇ -fetoprotein (AFP) transcriptional regulatory element” is polynucleotide sequence, preferably a DNA sequence, which selectively increases transcription (of an operably linked polynucleotide sequence) in a host cell that allows an .4ER-TRE to function, such as a cell (preferably a mammalian cell, even more preferably a human cell) that expresses AFP.
• the AFP-TRE is responsive to transcription factors and/or co-factor(s) associated with AFP-producing cells and comprises at least a portion of the AFP promoter and/or enhancer.
• an "a mucin gene (MUC) transcriptional regulatory element" or
• MUC1 -TRE is a polynucleotide sequence, preferably a DNA sequence, which selectively increases transcription (of an operably-linked polynucleotide sequence) in a host cell that allows an MUC1 -TRE to function, such as a cell (preferably a mammalian cell, even more preferably a human cell) that expresses MUC1.
• the MUC1 -TRE is responsive to transcription factors and/or co-factor(s) associated with MUC1 -producing cells and comprises at least a portion of the MUC1 promoter and/or enhancer.
• a "cell-specific TRE" is preferentially functional in a specific type of cell relative to other types of cells of different functionality.
• a cell-specific TRE may or may not be tumor cell specific.
• target cell-specific is intended to mean that the TRE sequences to which a gene essential for replication of an adenoviral vector is operably linked, or to which a transgene is operably linked, functions specifically in that target cell so that replication proceeds in that target cell, or so that a transgene polynucleotide is expressed in that target cell. This can occur by virtue of the presence in that target cell, and not in non-target cells, of transcription factors that activate transcription driven by the operably linked transcriptional control sequences. It can also occur by virtue of the absence of transcription inhibiting factors that normally occur in non-target cells and prevent transcription driven by the operably linked transcriptional control sequences.
• target cell-specific is intended to include cell type specificity, tissue specificity, as well as specificity for a cancerous state of a given target cell. In the latter case, specificity for a cancerous state of a normal cell is in comparison to a normal, non- cancerous counterpart.
• the activity of a TRE generally depends upon the presence of transcriptional regulatory factors and/or the absence of transcriptional regulatory inhibitors. Transcriptional activation can be measured in a number of ways known in the art (and described in more detail below), but is generally measured by detection and/or quantitation of mRNA or the protein product of the coding sequence under control of (i.e., operatively linked to) the TRE.
• a TRE can be of varying lengths, and of varying sequence composition.
• transcriptional activation it is intended that transcription will be increased above basal levels in the target cell by at least about 2-fold, preferably at least about 5-fold, preferably at least about 10-fold, more preferably at least about 20-fold. More preferably at least about 50-fold, more preferably at least about 100-fold, even more preferably at least about 200-fold, even more preferably at least about 400- to about 500- fold, even more preferably, at least about 1000-fold.
• Basal levels are generally the level of activity, if any, in a non-target cells, or the level of activity (if any) of a reporter construct lacking the TRE of interest as tested in a target cell type.
• a "functionally-preserved" variant of a TRE is a TRE which differs from another TRE, but still retains ability to increase transcription of an operably linked polynucleotide, especially cell-specific transcription activity.
• the difference in a TRE can be due to differences in linear sequence, arising from, for example, single or multiple base mutation(s), addition(s), deletion(s), and/or modification s) of the bases. The difference can also arise from changes in the sugar(s), and/or linkage(s) between the bases of a TRE.
• Certain point mutations within sequences of TREs have been shown to decrease transcription factor binding and gene activation.
• One of skill in the art would recognize that some alterations of bases in and around known the transcription factor binding sites are more likely to negatively affect gene activation and cell-specificity, while alterations in bases which are not involved in transcription factor binding are not as likely to have such effects.
• Certain mutations are also capable of increasing TRE activity. Testing of the effects of altering bases may be performed in vitro or in vivo by any method known in the art, such as mobility shift assays, or transfecting vectors containing these alterations in TRE functional and TRE non-functional cells. Additionally, one of skill in the art would recognize that point mutations and deletions can be made to a TRE sequence without altering the ability of the sequence to regulate transcription.
• Under transcriptional control is a term well-understood in the art and indicates that transcription of a polynucleotide sequence, usually a DNA sequence, depends on its being operably (operatively) linked to an element which contributes to the regulation of, either promotes or inhibits, transcription.
• operably linked relates to the orientation of polynucleotide elements in a functional relationship.
• a TRE is operably linked to a coding segment if the TRE promotes transcription of the coding sequence.
• Operably linked means that the DNA sequences being linked are generally contiguous and, where necessary to join two protein coding regions, contiguous and in the same reading frame. However, since enhancers generally function when separated from the promoter by several kilobases and intronic sequences may be of variable length, some polynucleotide elements may be operably linked but not contiguous.
• a “target cell” is any cell that allows a heterologous TRE to function.
• a target cell is a mammalian cell, more preferably a human cell.
• “neoplastic cells”, “neoplasia”, “tumor”, “tumor cells”, “cancer”, and “cancer cells” refer to cells which exhibit relatively autonomous growth, so that they exhibit an aberrant growth phenotype characterized by a significant loss of control of cell proliferation. Neoplastic cells can be benign or malignant.
• AR refers to a protein whose function is to specifically bind to androgen and, as a consequence of the specific binding, recognize and bind to an androgen response element (ARE), following which the AR is capable of regulating transcriptional activity.
• the AR is a nuclear receptor that, when activated, binds to cellular androgen-responsive element(s). In normal cells the AR is activated by androgen, but in non-normal cells (including malignant cells) the AR may be activated by non-androgenic agents, including hormones other than androgens. Encompassed in the term “androgen receptor” are mutant forms of an androgen receptor, as long as the function is sufficiently preserved.
• Mutants include androgen receptors with amino acid additions, insertions, truncations and deletions, as long as the function is sufficiently preserved.
• a functional androgen receptor is one that binds both androgen and, upon androgen binding, an ARE.
• an "adenovirus vector” or “adenoviral vector” is a term well understood in the art and generally comprises a polynucleotide (defined herein) comprising all or a portion of an adenovirus genome.
• an adenovirus vector contains a heterologous TRE operably linked to a polynucleotide.
• the operably linked polynucleotide can be adenoviral or heterologous.
• An adenovirus is exemplified by, but not limited to, Ad2, Ad5, Adl2, and Ad40.
• Ad2, Ad5, Adl2, and Ad40 The terms “vector”, “polynucleotide vector”, “construct”, “polynucleotide construct” and “vector construct” are used interchangeably herein.
• An adenoviral vector of this invention may be in any of several forms, including, but not limited to, naked DNA, DNA encapsulated in an adenovirus coat, DNA packaged in another viral or viral-like form (such as herpes simplex, and AAV), DNA encapsulated in liposomes, DNA complexed with polylysine, complexed with synthetic polycationic molecules, conjugated with transferrin, complexed with compounds such as PEG to immunologically "mask" the molecule and/or increase half-life, or conjugated to a non-viral protein.
• adenovirus vectors are replication-competent in a target cell.
• Heterologous means derived from a genotypically distinct entity from that of the rest of the entity to which it is being compared.
• a “heterologous” TRE is one which is not associated with or derived from a wild- type adenovirus.
• heterologous TREs are the albumin promoter or enhancer and other viral promoters and enhancers, such as SV40. Examples of preferred heterologous TREs are provided herein.
• a “heterologous gene” or “transgene” is any gene that is not present in wild-type adenovirus. Preferably, the transgene will also not be expressed or present in the target cell prior to introduction by the adenovirus vector. Examples of preferred transgenes are provided below.
• replication involves production of adenovirus proteins and is generally directed to reproduction of adenovirus. Replication can be measured using assays standard in the art and described herein, such as a burst assay or plaque assay.
• Replication and propagation include any activity directly or indirectly involved in the process of virus manufacture, including, but not limited to, viral gene expression, production of viral proteins, nucleic acids or other components, packaging of viral components into complete viruses, and cell lysis.
• a "gene essential for replication” is a gene whose transcription is required for the vector to replicate in a cell.
• polypeptide polypeptide
• a "host cell” includes an individual cell or cell culture which can be or has been a recipient of an adenoviral vector of this invention.
• Host cells include progeny of a single host cell, and the progeny may not necessarily be completely identical (in morphology or in total DNA complement) to the original parent cell due to natural, accidental, or deliberate mutation and/or change.
• a host cell includes cells transfected or infected in vivo with an adenoviral vector of this invention.
• cytotoxicity is a term well understood in the art and refers to a state in which one or more of a cell's usual biochemical or biological functions are aberrantly compromised (i.e., inhibited or elevated). These activities include, but are not limited to, metabolism, cellular replication, DNA replication, transcription, translation, and uptake of molecules. "Cytotoxicity” includes cell death and/or cytolysis. Assays are known in the art which indicate cytotoxicity, such as dye exclusion, H-thymidine uptake, and plaque assays.
• selective cytotoxicity refers to the cytotoxicity conferred by an adenoviral vector of the present invention on a cell which allows a TRE to function when compared to the cytotoxicity conferred by an adenoviral vector of the present invention on a cell which does not allow, or is less permissive for, the same TRE to function.
• Such cytoxicity may be measured, for example, by plaque assays, reduction or stabilization in size of a tumor comprising target cells, or the reduction or stabilization of serum levels of a marker characteristic of the tumor cells or a tissue- specific marker, e.g., a cancer marker such as prostate specific antigen.
• cytotoxic gene is a gene whose expression in a cell, either alone or in conjunction with adenovirus replication, enhances the degree and/or rate of cytotoxic and/or cytolytic activity in the cell.
• a "therapeutic" gene is a gene whose expression in a cell is associated with a desirable result.
• this desirable result may be, for example, cytotoxicity, repression or slowing of cell growth, and/or cell death.
• a “biological sample” encompasses a variety of sample types obtained from an individual and can be used in a diagnostic or monitoring assay.
• the definition encompasses blood and other liquid samples of biological origin, solid tissue samples such as a biopsy specimen or tissue cultures or cells derived therefrom and the progeny thereof.
• the definition also includes samples that have been manipulated in any way after their procurement, such as by treatment with reagents, solubihzation, or enrichment for certain components, such as proteins or polynucleotides.
• the term “biological sample” encompasses a clinical sample, and also includes cells in culture, cell supernatants, cell lysates, serum, plasma, biological fluid, and tissue samples.
• An "individual” is a vertebrate, preferably a mammal, more preferably a human.
• Mammals include, but are not limited to, farm animals, sport animals, and pets.
• an "effective amount” is an amount sufficient to effect beneficial or desired clinical results.
• An effective amount can be administered in one or more administrations.
• an effective amount of an adenoviral vector is an amount that is sufficient to palliate, ameliorate, stabilize, reverse, slow or delay the progression of the disease state.
• treatment is an approach for obtaining beneficial or desired clinical results.
• beneficial or desired clinical results include, but are not limited to, alleviation of symptoms, diminishment of extent of disease, stabilized (i.e., not worsening) state of disease, preventing spread (i.e., metastasis) of disease, delay or slowing of disease progression, amelioration or palliation of the disease state, and remission (whether partial or total), whether detectable or undetectable.
• Treatment can also mean prolonging survival as compared to expected survival if not receiving treatment.
• a “masked adenovirus” is an adenovirus which has been complexed with a hydrophilic polymer ("masking agent").
• the adenovirus may be any adenovirus, including naturally occurring isolates of adenovirus or engineered adenovirus vectors such as those disclosed in the instant application. Masking agents are preferably of low immunogenicity.
• acceptable hydrophilic polymers include: polyethylene/polypropylene copolymers, polyacrylic acid analogues, sugar polymers such as cellulose, polyformaladehyde, poly(N-vinylpyrollidone), polyethylene glycol (PEG), and the like.
• the hydrophilic polymer may be complexed by covalent or non-covalent attachment to the capsid proteins of the virus, particularly the hexon and fiber capsid proteins.
• a preferred hydrophilic polymer is PEG, and a preferred masked adenovirus is PEG covalently linked to adenovirus ("covalently pegylated adenovirus").
• “Palliating" a disease means that the extent and/or undesirable clinical manifestations of a disease state are lessened and/or time course of the progression is slowed or lengthened, as compared to not administering adenoviral vectors of the present invention.
• Adenoviral vectors comprising heterologous TREs
• the present invention provides adenoviral vectors which comprise a first adenovirus gene under transcriptional control of a heterologous (i.e., non-adenovirus) TRE and at least a second gene under transcriptional control of a second heterologous TRE, wherein the two heterologous TREs are different from each other (in nucleotide sequence) but are functional in the same cell.
• at least the first heterologous TRE is cell- specific.
• the adenovirus gene is one that contributes to cytotoxicity (whether direct and/or indirect), more preferably one that contributes to and/or causes cell death, and even more preferably the first adenoviral gene is essential from adenovirus replication.
• Examples of an adenovirus gene that contributes to cytotoxicity include, but are not limited to, the adenovirus death protein gene. See Fig.l for diagrammatic examples. Because the adenovirus vector(s) is selectively (i.e. preferentially) replication- competent for propagation in target cells which allow the function of the heterologous TREs, these cells will be preferentially subject to the cytotoxic and/or cytolytic effects of adenoviral proliferation.
• target cells are neoplastic cells, although any cell for which it is desirable and/or tolerable to sustain this cytotoxic activity may be a target cell.
• the adenovirus vector(s) preferentially replicates in the target cells. Once the target cells are destroyed due to selective cytotoxic and/or cytolytic replication, the adenovirus vector(s) replication is significantly reduced, lessening the probability of runaway infection and undesirable bystander effects. In vitro cultures may be retained to continually monitor the mixture (such as, for example, a biopsy or other appropriate biological sample) for occurrence (i.e. presence) and/or recurrence of the target cell, e.g., a cancer cell in which the cell specific TRE is functional.
• one or more transgenes having a cytotoxic effect may also be present and under the selective transcriptional control of a heterologous TRE.
• an adenovirus gene that contributes to cytotoxicity and/or cell death such as the adenovirus death protein (ADP) gene
• ADP adenovirus death protein
• the invention provides an adenovirus vector comprising an adenovirus gene essential for replication under transcriptional control of a heterologous, cell specific TRE, wherein the TRE selectively regulates the expression of said gene in a target cell.
• the adenovirus vector comprises a second gene under transcriptional control of a second heterologous TRE, wherein the first and second heterologous TREs are functional in the same cell and the TREs are different from each other.
• TREs may be derived from the transcriptional regulatory sequences of a single gene or from different genes and combined to produce a functional TRE.
• a cell-specific TRE is preferentially functional in a limited population (or type) of cells, e.g., prostate cells or liver cells.
• activity of TREs can be inducible.
• Inducible TREs generally exhibit low activity in the absence of the inducer, and are up-regulated in the presence of the inducer.
• Inducible TREs may be preferred when expression is desired only at certain times or at certain locations, or when it is desirable to titrate the level of expression using an inducing agent.
• transcriptional activity from the RSE- TRE, RR-TRE and hKLK2-TRE is inducible by androgen, as described herein.
• a heterologous TRE of the adenovirus vector is inducible.
• TRE can also comprise multimers.
• a TRE can comprise a tandem series of at least two, at least three, at least four, at least five promoter fragments.
• a TRE could have one or more promoter regions along with one or more enhancer regions.
• These multimers may also contain promoter and/or enhancer sequences from different genes.
• the promoter and enhancer components of a TRE may be in any orientation and/or distance from the coding sequence of interest, as long as the desired cell-specific transcriptional activity is obtained.
• a TRE used in the present invention may or may not lack a silencer.
• a silencer i.e., a negative regulatory element known in the art
• presence of a silencer can confer enhanced cell-specific replication by more effectively preventing adenoviral vector replication in non-target cells.
• lack of a silencer may assist in effecting replication in target cells, thus conferring enhanced cell-specific replication due to more effective replication in target cells.
• the heterologous TREs When used in an adenovirus vector of the present invention, the heterologous TREs have a different polynucleotide sequence from each other. Accordingly, in a given adenovirus vector, the sequence identity between the two heterologous TREs is less than about 95%>, preferably less than about 90%>, more preferably less than about 85%, more preferably less than 80%>, even more preferably less than about 75%. Despite the difference in sequence identity, the heterologous TREs of a given adenovirus vector are functional in the same cell. The difference(s) may arise from, for example, varying the sequence of a TRE derived from a single gene. It is possible to generate such TREs using standard methods in the art and/or allowing sequences to alter during the course of propagation. The difference(s) may also arise from TREs that are derived from different genes.
• a TRE is a polynucleotide sequence, and, as such, can exhibit function over a variety of sequence permutations.
• nucleotide substitution, addition, and deletion are known in the art, and readily available functional assays (such as the CAT or luciferase reporter gene assay) allow one of ordinary skill to determine whether a sequence variant exhibits requisite cell-specific transcription function.
• functional assays such as the CAT or luciferase reporter gene assay
• TREs may also be used including nucleic acid substitutions, additions, and/or deletions.
• variants of TREs must retain function in the target cell but need not be of maximal function.
• nucleic acid sequence deletions or additions within a TRE may decrease or increase transcription if they bring transcription regulatory protein binding sites too close or too far away or rotate them so they are on opposite sides of the DNA helix, as is known in the art.
• certain modifications will result in modulated resultant expression levels, including enhanced cell-specific expression levels. Achievement of enhanced expression levels may be especially desirable in the case of more aggressive forms of neoplastic growth, or when a more rapid and/or aggressive pattern of cell killing is warranted (due to an immunocompromised condition of the individual, for example).
• Transcriptional activity can be measured in a number of ways known in the art (and described in more detail below), but is generally measured by detection and/or quantitation of mRNA or the protein product of the coding sequence under control of (i.e., operably linked to) a TRE.
• a TRE can be of varying lengths, and of varying sequence composition.
• transcriptional activity it is intended that transcription due to the presence of the enhancer is increased above basal levels (i.e., promoter alone; lacking enhancer) in the target cell by at least about 2-fold, preferably at least about 5-fold, preferably at least about 10-fold, more preferably at least about 20-fold, more preferably at least about 50-fold, more preferably at least about 100-fold, more preferably at least about 200-fold, even more preferably at least about 400- to about 500-fold, even more preferably at least about 1000-fold.
• Basal levels are generally the level of activity, if any, in a non-target cell, or the level of activity (if any) of a reporter construct lacking a TRE as tested in a non-target cell.
• Maximal transcriptional activation activity of a TRE may not always be necessary to achieve a desired result.
• the level of induction afforded by a fragment of a TRE may be sufficient in certain applications to achieve a desired result. For example, if used for treatment or palliation of a disease state, less-than-maximal responsiveness may be sufficient for the desired result, if, for example, the target cells are not especially virulent and/or the extent of disease is relatively confined.
• the size of the heterologous TREs will be determined in part by the capacity of the adenoviral vector, which in turn depends upon the contemplated form of the vector (see below).
• an adenoviral vector can be packaged with extra sequences totaling up to about 5%> of the genome size, or approximately 1.8 kb. If non-essential sequences are removed from the adenovirus genome, an additional 4.6 kb of insert can be tolerated (i.e., a total of about 1.8 kb plus 4.6 kb, which is about 6.4 kb). Examples of non-essential adenoviral sequences that can be deleted are E3 and E4 (as long as the E4 ORF6 is maintained). In order to minimize non-specific replication, endogenous (i.e., adenovirus) TREs should preferably be removed.
• an adenoviral vector of the invention is constructed such that the endogenous transcription control sequences of adenoviral genes are deleted and replaced by a heterologous TREs.
• endogenous TREs may be maintained in the adenovirus vector(s), provided that sufficient cell-specific replication preference is preserved.
• These embodiments can be constructed by providing heterologous TREs intervening between the endogenous TRE and the replication gene coding segment. Requisite cell-specific replication preference is indicated by conducting assays that compare replication of the adenovirus vector in a cell which allows function of the heterologous TREs with replication in a cell which does not.
• replication is increased above basal levels in the target cell by at least about 2-fold, preferably at least about 5-fold, preferably at least about 10- fold more preferably at least about 20-fold, more preferably at least about 50-fold, more preferably at least about 100-fold, more preferably at least about 200-fold, even more preferably at least about 400- to about 500- fold, even more preferably at least about 1000- fold.
• the acceptable differential can be determined empirically (using, for example, Northern assays or other known in the art) and will depend upon the anticipated use of the adenoviral vector and or the desired result.
• the invention includes adenovirus vectors wherein the heterologous TREs are prostate cell specific.
• TREs that function preferentially in prostate cells and can be used in the present invention to target adenovirus replication to prostate neoplasia include, but are not limited to, TREs derived from the prostate-specific antigen gene (R&4-TRE), the glandular kallikrein-1 gene (from the human gene, hKLK2-TRE), and the probasin gene (RR-TRE). All three of these genes are preferentially expressed in prostate cells and the expression is androgen-inducible. Generally, expression of genes responsive to androgen induction requires the presence of an androgen receptor (AR).
• AR androgen receptor
• PSA is synthesized exclusively by normal, hyperplastic, and malignant prostatic epithelia; hence, its tissue-specific expression has made it an excellent biomarker for benign prostatic hyperplasia (BPH) and prostatic carcinoma (CaP).
• BPH benign prostatic hyperplasia
• CaP prostatic carcinoma
• Normal serum levels of PSA are typically below 5 ng/ml, with elevated levels indicative of BPH or CaP. Lundwall et al. (1987) EERS ett. 214: 317; Lundwall (1989) Biochem. Biophys. Res.
• the PSA promoter consists of the sequence from about nt -540 to nt +8 relative to the transcription start site. Juxtapositioning of these two genetic elements yield a fully functional, minimal prostate-specific enhancer/promoter (PSE) TR ⁇ .
• PSE minimal prostate-specific enhancer/promoter
• the RSE and PSA TR ⁇ depicted in (S ⁇ Q ID NO: 1) is the same as that given in GenBank Accession No. U37672, and published. Schuur et al. (1996).
• a variant PSA- TR ⁇ nucleotide sequence is depicted in (S ⁇ Q ID NO:2). This is the R&4-TR ⁇ contained within CN706 clone 35.190.13.
• CN706 is an adenoviral vector in which the El A gene in Ad5 is under transcriptional control of a R&4-TRE. CN706 demonstrates selective cytotoxicity toward PSA-expressing cells in vitro and in vivo. Rodriguez et al. (1997). CN706 was passaged through 293 and LNCaP cells.
• a clone, designated 35.190.13 was isolated. The structure of this clone was confirmed by PCR, restriction endonuclease digestion and Southern blotting. Both DNA strands of the CN706 clone 35.190.13 were sequenced between positions 1 and 3537. Seven single base pair changes were found in the PSE, compared to the sequence reported by Schuur et al. (1996). These point mutations are not in the ARE and are thus not likely to affect the function of the enhancer. One mutation was found in the PSA promoter region, but is not likely to affect gene expression from this promoter. In addition to these mutations, a missense mutation was found in the first exon of El A.
• hK2 found in various tumors and in the serum of patients with prostate cancer differ substantially from those of PSA and indicate that hK2 antigen may be a significant marker for prostate cancer. Circulating hK2 in different relative proportions to PSA has been detected in the serum of patients with prostate cancer. Charlesworth et al. (1997) Urology 49:487-493. Expression of hK2 has been detected in each of 257 radical prostatectomy specimens analyzed. Darson et al. (1997) Urology 49:857-862.
• hKLK2 5' promoter The activity of the hKLK2 5' promoter has been previously described and a region up to -2256 relative to the transcription start site was previously disclosed. Schedlich et al. (1987) DNA 6:429-437.
• the hKLK2 promoter is androgen responsive and, in plasmid constructs wherein the promoter alone controls the expression of a reporter gene, expression of the reporter gene is increased approximately 10-fold in the presence of androgen.
• hKLK2 enhancer activity is found within a polynucleotide sequence approximately nt -12,014 to nt -2257 relative to the start of transcription (depicted in SEQ ID NO:3) and, when this sequence is operably linked to an hKLK2 promoter and a reporter gene, transcription of operably-linked sequences in prostate cells increases in the presence of androgen at levels approximately
• Enhancer activity has also been demonstrated in the following regions (all relative to the transcription start site): about nt -3993 to about nt -3643 (nt 8021 to 8371 of SEQ ID NO:3), about nt -4814 to about nt -3643 (nt 7200 to 8371 of SEQ ID NO:3), about nt - 5155 to about nt -3387 (nt 6859 to 8627 of SEQ ID NO:3), about nt -6038 to about nt - 2394 (nt 5976 to 9620 of SEQ ID NO:3).
• an hKLK2 enhancer can be operably linked to an hKLK2 promoter or a heterologous promoter to form an hKLK2 transcriptional regulatory element (hKLK2- TRE).
• An hKLK2-TRE can then be operably linked to a heterologous polynucleotide to confer /z- ⁇ O-TRE-specific transcriptional regulation on the linked gene, thus increasing its expression.
• the rat probasin (RR) gene encodes a nuclear and secreted protein, probasin, that is only expressed in the dorsolateral prostate.
• the dorsolateral lobes of the murine prostate are considered the most homologous to the peripheral zone of the human prostate, where approximately 68% of human prostate cancers are thought to originate.
• a RR-TRE has been shown in an approximately 0.5 kb fragment of sequence upstream of the probasin coding sequence, from about nt -426 to about nt +28 relative to the transcription start site,as depicted in (SEQ ID NO:4).
• This minimal promoter sequence from the PB gene appears to provide sufficient information to direct development and hormone -regulated expression of an operably linked heterologous gene specifically to the prostate in transgenic mice.
• TREs derived from prostate cell specific TREs may be used in the present invention to generate stable adenovirus vectors that preferentially replicate in cells in which the TREs are functional, such as cells expressing an AR, particularly cells derived from prostate neoplasia.
• the invention includes adenovirus vectors in which the first heterologous TRE is a R&4-TRE (e.g., RSE-TRE) and the second heterologous TRE is a RR-TRE, in which the first heterologous TRE is a RR-TRE and the second heterologous TRE is a PSA- TRE (e.g., RSE-TRE), in which the first heterologous TRE is an hKLK2-TRE and the second heterologous TRE is a R&4-TRE (e.g., RSE-TRE), in which the first heterologous
• R&4-TRE e.g., RSE-TRE
• TRE is a RS -TRE (e.g., RSE-TRE) and the second heterologous TRE is an hKLK2-TRE, in which the first heterologous TRE is an hKLK2-TRE and the second heterologous TRE is a RR-TRE, in which the first heterologous TRE is a RR-TRE and the second heterologous TRE is an hKLK2-TRE, as described above. See Examples 1-4, Fig. 2.
• replication-competent adenovirus vectors directed at specific target cells may also be generated with the use of TREs that are preferentially functional in the target tumor cells.
• Non-limiting examples of tumor cell-specific heterologous TREs include TREs from the following genes: ⁇ -fetoprotein (AFP) (liver cancer), mucin-like glycoprotein DF3 (MUC1) (breast carcinoma), carcinoembryonic antigen (CEA) (colorectal, gastric, pancreatic, breast, and lung cancers), plasminogen activator urokinase (uPA) and its receptor gene (breast, colon, and liver cancers), E2F1 (cell cycle S-phase specific promoter) (tumors with disrupted retinoblastoma gene function), HER-2/neu (c- erbB2/neu) (breast, ovarian, stomach, and lung cancers).
• AFP ⁇ -fetoprotein
• MUC1 mucin-like glycoprotein DF3
• CEA carcinoembryonic antigen
• uPA plasminogen activator urokinase
• E2F1 cell
• tumor-specific TREs may be used in conjunction with tissue-specific TREs from the following exemplary genes (tissue in which the TREs are specifically functional are in parentheses): hypoxia responsive element, vascular endothelial growth factor receptor (endothelium), albumin (liver), factor VII (liver), fatty acid synthase (liver), Von Willebrand factor (brain endothelium), alpha-actin and myosin heavy chain (both in smooth muscle), synthetast I (small intestine), Na-K-Cl transporter (kidney). Additional tissue specific TREs are known in the art. Accordingly, in one embodiment, the cell specific, heterologous TRE is tumor cell specific.
• both heterologous TREs are tumor cell specific and functional in the same cell.
• one of the first heterologous TREs is tumor cell specific and the second heterologous TRE is tissue specific, whereby both TREs are function in the same cell.
• AFP is an oncofetal protein, the expression of which is primarily restricted to developing tissues of endodermal origin (yolk sac, fetal liver, and gut), although the level of its expression varies greatly depending on the tissue and the developmental stage. AFP is of clinical interest because the serum concentration of AFP is elevated in a majority of hepatoma patients, with high levels of AFP found in patients with advanced disease.
• the serum AFP levels in patients appear to be regulated by AFP expression in hepatocellular carcinoma but not in surrounding normal liver.
• the AFP gene appears to be regulated to hepatoma cell-specific expression.
• Cell-specific TREs from the AFP gene have been identified. For example, the cloning and characterization of human AFP-specific enhancer activity is described in Watanabe et al. (1987) J. Biol. Chem. 262:4812-4818.
• the entire 5' AFP flanking region (containing the promoter, putative silencer, and enhancer elements) is contained within approximately 5 kb upstream from the transcription start site (SEQ ID NO:5).
• the AFP enhancer region in human is located between about nt -3954 and about nt -3335, relative to the transcription start site of the AFP gene.
• the human AFP promoter encompasses a region from about nt -174 to about nt +29. Juxtapositioning of these two genetic elements, as depicted in SEQ ID NO:6, yields a fully functional ⁇ FR-TRE. Ido et al. (1995) describe a 259 bp promoter fragment (nt -230 to nt +29) that is specific for
• the AFP enhancer contains two regions, denoted A and B, located between nt -3954 and nt -3335 relative to the transcription start site.
• the promoter region contains typical TATA and CAAT boxes.
• the .4ER-TRE contains at least one enhancer region. More preferably, the -4FR-TRE contains both enhancer regions.
• Suitable target cells for adenoviral vectors containing yfER-TREs are any cell type that allow an AFP-TRE to function.
• Preferred are cells that express, or produce, AFP, including, but not limited to, tumor cells expressing AFP. Examples of such cells are hepatocellular carcinoma cells, gonadal and other germ cell tumors (especially endodermal sinus tumors), brain tumor cells, ovarian tumor cells, acinar cell carcinoma of the pancreas
• AFP production can be measured using assays standard in the art, such as RIA, ELISA or Western blots (immunoassays) to determine levels of AFP protein production or Northern blots to determine levels of AFP mRNA production.
• assays standard in the art, such as RIA, ELISA or Western blots (immunoassays) to determine levels of AFP protein production or Northern blots to determine levels of AFP mRNA production.
• assays standard in the art such as RIA, ELISA or Western blots (immunoassays) to determine levels of AFP protein production or Northern blots to determine levels of AFP mRNA production.
• such cells can be identified and/or characterized by their ability to activate transcriptionally an ER-TRE (i.e., allow an ER-TRE to function).
• uPA protein urokinase plasminogen activator
• uPAR urokinase plasminogen activator receptor
• cell-specific TREs including but not limited to those described herein, could be used in the present invention to generate stable adenovirus vectors that preferentially replicate in cells in which the TREs are functional, such as cells derived from liver neoplasia.
• the invention includes adenovirus vectors wherein at least one of the heterologous TREs are liver cell-specific.
• the invention includes adenovirus vectors in which the first heterologous TRE is an AFP- TRE and the second heterologous TRE is an WR.4-TRE, in which the first heterologous TRE is an uPA-TRE and the second heterologous TRE is an AFP-TRE, in which the first heterologous TRE is an -4ER-TRE and the second heterologous TRE is an albumin-TRE, in which the first heterologous TRE is an albumin-TRE and the second heterologous TRE is an AFP-TRE, as described above.
• CEA is a 180,000-Dalton glycoprotein tumor-associated antigen present on endodermally-derived neoplasia of the gastrointestinal tract, such as colorectal, gastric (stomach) and pancreatic cancer, as well as other adenocarcinomas such as breast and lung cancers.
• CEA is of clinical interest because circulating CEA can be detected in the great majority of patients with CEA-positive tumors.
• lung cancer about 50% of total cases have circulating CEA, with high concentrations of CEA (greater than 20 ng/ml) often detected in adenocarcinomas.
• Approximately 50% of patients with gastric carcinoma are serologically positive for CEA.
• the 5' upstream flanking sequence of the CEA gene has been shown to confer cell- specific activity.
• the CEA promoter region approximately the first 424 nucleotides upstream of the translational start site in the 5' flanking region of the gene, was shown to confer cell-specific activity when the region provided higher promoter activity in CEA- producing cells than in non-producing HeLa cells.. Schrewe et al. (1990) Mol. Cell. Biol. 10:2738-2748. In addition, cell-specific enhancer regions have been found.
• WO95/14100 describes a series of 5' flanking CEA fragments which confer cell-specific activity, such as about nt -299 to about nt +69; about nt -90 to about nt +69; nt -14,500 to nt -10,600; nt -13,600 to nt - 10,600, nt -6100 to nt -3800.
• cell specific transcription activity is conferred on an operably linked gene by the CEA fragment from nt -402 to nt +69, depicted in (SEQ ID
• Any CE-4-TREs used in the present invention are derived from mammalian cells, including but not limited to, human cells. Thus, any of the CE4-TREs may be used in the invention as long as requisite desired functionality is displayed in the adenovirus vector.
• the cloning and characterization of CEA sequences have been described in the literature and are thus made available for practice of this invention and need not be described in detail herein.
• the protein product of the MUC1 gene (known as mucin or MUC1 protein; episialin; polymorphic epithelial mucin or PEM; EMA; DF3 antigen; NPGP; PAS-O; or CA15.3 antigen) is normally expressed mainly at the apical surface of epithelial cells lining the glands or ducts of the stomach, pancreas, lungs, trachea, kidney, uterus, salivary glands, and mammary glands. Zotter et al. (1988) Cancer Rev. 11-12: 55-101; and Girling et al. (1989) Int. J. Cancer 43: 1072-1076.
• Mucin protein expression correlates with the degree of breast tumor differentiation. Lundy et al. (1985) Breast Cancer Res. Treat. 5: 269-276. This overexpression appears to be controlled at the transcriptional level.
• the regulatory sequences of the MUC1 gene have been cloned, including the approximately 0.9 kb upstream of the transcription start site which contains a TRE that appears to be involved in cell-specific transcription, depicted in SEQ ID NO:8.
• any MUCl -TREs used in the present invention are derived from mammalian cells, including but not limited to, human cells.
• the MUCl -TRE is human.
• the L -TRE may contain the entire 0.9 kb 5' flanking sequence of the
• the MUCl -TREs comprise the following sequences (relative to the transcription start site of the MUCl gene): about nt -725 to about nt +31 , nt -743 to about nt +33, nt -750 to about nt +33, and nt -598 to about nt +485 (operably- linked to a promoter).
• the c-erbB2/neu gene (HER-2/neu or HER) is a transforming gene that encodes a
• the c-erbB2/neu protein is expressed during fetal development, however, in adults, the protein is weakly detectable (by immunohistochemistry) in the epithelium of many normal tissues. Amplification and/or over-expression of the c-erbB2/neu gene has been associated with many human cancers, including breast, ovarian, uterine, prostate, stomach and lung cancers. The clinical consequences of the c-erbB2/neu protein over-expression have been best studied in breast and ovarian cancer.
• c-erbB2/neu protein over-expression occurs in 20 to 40% of intraductal carcinomas of the breast and 30% of ovarian cancers, and is associated with a poor prognosis in subcategories of both diseases.
• Human, rat and mouse c-erbB2/neu TREs have been identified and shown to confer c-erbB2/neu expressing cell specific activity.
• TREs derived from breast cell-specific TREs may be used in the present invention to generate stable adenovirus vectors that preferentially replicate in cells in which the TREs are functional, particularly cells derived from breast neoplasia.
• the invention includes adenovirus vectors wherein the heterologous TREs are breast cell-specific.
• the invention includes adenovirus vectors in which the first heterologous TRE is a CEA-TRE and the second heterologous TRE is a MUCl -TRE, in which the first heterologous TRE is a MUCl -TRE and the second heterologous TRE is a CEA-TRE, in which the first heterologous TRE is a MUCl -TRE and the second heterologous TRE is a HER-TRE, in which the first heterologous TRE is a HER-TRE and the second heterologous TRE is an MUCl -TRE, in which the first heterologous TRE is a c7C7-TRE and the second heterologous TRE is a uPA-TRE, in which the first heterologous TRE is a uPA-TRE and the second heterologous TRE is a MUCl -TRE, in which the first heterologous TRE is a uPA-TRE and the second heterologous TRE is an ⁇ ER
• TREs derived from colon cell-specific TREs may be used in the present invention to generate stable adenovirus vectors that preferentially replicate in cells in which the TREs are functional, particularly cells derived from colon neoplasia.
• the invention includes adenovirus vectors wherein the heterologous TREs are colon cell-specific.
• the invention includes adenovirus vectors in which the first heterologous TRE is a CE.4-TRE and the second heterologous TRE is a MR4-TRE, in which the first heterologous TRE is a uPA-TRE and the second heterologous TRE is a CE4-TRE, as described above.
• adenovirus vectors of the present invention may be useful in the treatment of more than one type of neoplasm, as can be determined by the information provided herein.
• TREs listed above are provided as non-limiting examples of TREs that would function in the instant invention. Additional cell-specific TREs are known in the art, as are methods to identify and test cell specificity of suspected TREs. Further, and as noted above, the invention does not require that the TREs be derived from different genes. As long as the TRE sequences are sufficiently different, and the requisite functionality is diplayed, the different TREs may be derived from the same gene.
• activity of a TRE can be determined as follows.
• a TRE polynucleotide sequence or set of such sequences can be generated using methods known in the art, such as chemical synthesis, site-directed mutagenesis, PCR, and/or recombinant methods.
• the sequence(s) to be tested can be inserted into a vector containing a promoter
• reporter gene encoding a reporter protein, including, but not limited to, chloramphenicol acetyl transferase (CAT), ⁇ -galactosidase (encoded by the lacZ gene), luciferase (encoded by the luc gene), alkaline phosphatase, green fluorescent protein, and horse radish peroxidase.
• CAT chloramphenicol acetyl transferase
• ⁇ -galactosidase encoded by the lacZ gene
• luciferase encoded by the luc gene
• alkaline phosphatase green fluorescent protein
• horse radish peroxidase horse radish peroxidase
• Plasmids thus constructed are transfected into a suitable host cell to test for expression of the reporter gene as controlled by the putative TRE using transfection methods known in the art, such as calcium phosphate precipitation, electroporation, liposomes (lipofection), and DEAE dextran.
• TRE activity may be measured by detection and/or quantitation of reporter gene-derived mRNA or protein product.
• the reporter gene protein can be detected directly (e.g., immunochemically) or through its enzymatic activity, if any, with an appropriate substrate.
• the TRE- reporter gene constructs are introduced into a variety of cell types. The amount of TRE activity is determined in each cell type and compared to that of a reporter gene construct without the TRE.
• a TRE is cell specific when it is preferentially functional in a specific type of cell over a different type of cell.
• RR-TRE activity for prostate cell that express the androgen receptor (AR) was demonstrated as follows.
• the region of the PB 5 '-flanking DNA (nt -426 to nt +28) (SEQ ID NO:4) including the endogenous promoter sequences was inserted upstream of the firefly luciferase gene to generate a chimeric RR-TRE-luc plasmid.
• a cell specific, heterologous TRE is used to control transcription of an adenovirus gene and a second heterologous TRE, different from (i.e., not the same as) the first heterologous TRE, is used to control transcription of a second gene to provide an adenovirus vector so that replication-competence is preferentially achievable in target cells which allow for function of the cell-specific TRE.
• the two heterologous TREs are functional in the target cell.
• the first adenovirus gene is essential for adenoviral replication, even more preferably, both genes are essential for adenoviral replication.
• at least one of the genes is an early gene, such as EIA, EIB, E2, or E4.
• both genes under control of the heterologous TREs are early genes. More preferably, the early gene under cell-specific TRE control is EIA and/or EIB. Examples 1, 2 and 5 provide a more detailed description of such constructs.
• EIA gene is expressed immediately after viral infection (0-2 hours) and before any other viral genes.
• EIA protein acts as a tr- s-acting positive-acting transcriptional regulatory factor, and is required for the expression of the other early viral genes EIB, E2, E3, E4, and the promoter-proximal major late genes.
• the promoter proximal genes driven by the major late promoter are expressed during early times after Ad5 infection. Flint (1982) Biochem. Biophys. Ada 651:175-208; Flint (1986) Advances Virus Research 31 :169-228; Grand (1987) Biochem. J 241 :25-38.
• the EIB protein functions in trans and is necessary for transport of late mRNA from the nucleus to the cytoplasm. Defects in EIB expression result in poor expression of late viral proteins and an inability to shut off host cell protein synthesis.
• the promoter of EIB has been implicated as the defining element of difference in the host range of Ad40 and Ad5: clinically Ad40 is an enterovirus, whereas Ad5 causes acute conjunctivitis. Bailey et al. (1993) Virology 193:631; Bailey et al. (1994) Virology 202:695-706.
• the EIB promoter of Ad5 consists of a single high-affinity recognition site for Spl and a TATA box.
• the adenovirus EIA gene is under transcriptional control of the cell specific, heterologous TRE.
• the adenovirus EIB gene is under transcriptional control of the cell specific, heterologous TRE.
• both the adenovirus EIA and EIB genes are under transcriptional control of two different heterologous TREs, preferably both TREs are cell specific.
• the E2 region of adenovirus codes for proteins related to replication of the adenoviral genome, including the 72 kD DNA-binding protein, the 80 kD precursor terminal protein and the viral DNA polymerase.
• the E2 region of Ad5 is transcribed in a rightward orientation from two promoters, termed E2 early and E2 late, mapping at 76.0 and 72.0 map units, respectively. While the E2 late promoter is transiently active during late stages of infection and is independent of the EIA transactivator protein, the E2 early promoter is crucial during the early phases of viral replication.
• the E2 early promoter, mapping in Ad5 from 27050-27150 consists of a major and a minor transcription initiation site, the latter accounting for about 5%> of the E2 transcripts, two non-canonical TATA boxes, two E2F transcription factor binding sites and an ATF transcription factor binding site.
• the E2 late promoter overlaps with the coding sequences of a gene encoded by the counterstrand and is therefore not amenable for genetic manipulation.
• the E2 early promoter overlaps only for a few base pairs with sequences coding for a 33 kD protein on the counterstrand.
• the Spel restriction site (Ad5 position 27082) is part of the stop codon for the above mentioned 33 kD protein and conveniently separates the major E2 early transcription initiation site and TATA-binding protein site from the upstream transcription factor binding sites E2F and ATF. Therefore, insertion of a heterologous TRE having Spel ends into the Spel site in the plus strand would disrupt the endogenous E2 early promoter of Ad5 and should allow TRE-regulated expression of E2 transcripts.
• the E4 gene has a number of transcription products.
• the E4 region codes for two polypeptides which are responsible for stimulating the replication of viral genomic DNA and for stimulating late gene expression.
• the protein products of open reading frames (ORFs) 3 and 6 can both perform these functions by binding the 55-kD protein from EIB and heterodimers of E2F-1 and DP-1.
• the ORF 6 protein requires interaction with the EIB 55-kD protein for activity while the ORF 3 protein does not. In the absence of functional protein from ORF 3 and ORF 6, plaques are produced with an efficiency less than 10 "6 that of wild type virus.
• E4 ORFs 1-3 can be deleted, making viral DNA replication and late gene synthesis dependent on E4 ORF 6 protein.
• a virus By combining such a mutant with sequences in which the EIB region is regulated by a target cell-specific TRE, a virus can be obtained in which both the EIB function and E4 function are dependent on the target cell-specific TRE driving EIB.
• the major late genes relevant to the subject invention are LI, L2 and L3, which encode proteins of the Ad5 virus virion. All of these genes (typically coding for structural proteins) are probably required for adenoviral replication. The late genes are all under the control of the major late promoter (MLP), which is located in Ad5 at +5986 to +6048.
• MLP major late promoter
• the adenovirus E4 gene is under transcriptional control of the cell specific, heterologous TRE.
• an adenovirus late gene is under transcriptional control of the cell specific, heterologous TRE.
• one early gene and one late gene are under transcriptional control of differrent heterologous TREs.
• the adenovirus vectors of this invention can further include a heterologous polynucleotide (transgene) under the control of a heterologous TRE.
• a heterologous polynucleotide transgene
• various genetic capabilities may be introduced into target cells. For example, in certain instances, it may be desirable to enhance the degree and/or rate of cytotoxic activity, due to, for example, the relatively refractory nature or particular aggressiveness of the target cell.
• cd cytosine deaminase
• Using these types of transgenes may also confer a bystander effect.
• transgenes that may be introduced via an adenovirus vector(s) include genes encoding cytotoxic proteins, such as the A chains of diphtheria toxin, ricin or abrin (Palmiter et al. (1987) Cell 50: 435; Maxwell et al. (1987) Mol. Cell. Biol. 7: 1576; Behringer et al. (1988) Genes Dev. 2: 453; Messing et al. (1992) Neuron 8: 507; Piatak et al. (1988) J Biol. Chem. 263: 4937; Lamb et al. (1985) Eur. J. Biochem. 148: 265; Frankel et al. (1989) Mol.
• cytotoxic proteins such as the A chains of diphtheria toxin, ricin or abrin
• genes encoding a factor capable of initiating apoptosis genes encoding a factor capable of initiating apoptosis, sequences encoding antisense transcripts or ribozymes, which among other capabilities may be directed to mRNAs encoding proteins essential for proliferation, such as structural proteins, or transcription factors; viral or other pathogenic proteins, where the pathogen proliferates intracellularly, genes that encode an engineered cytoplasmic variant of a nuclease (e.g. RNase A) or protease (e.g. awsin, papain, proteinase K, carboxypeptidase, etc.), or encode the Fas gene, and the like.
• a nuclease e.g. RNase A
• protease e.g. awsin, papain, proteinase K, carboxypeptidase, etc.
• genes of interest include potential therapeutic genes such as cytokines, antigens, transmembrane proteins, and the like, such as IL-1, -2, -6, -12, GM-CSF, G-CSF, M-CSF, IFN- ⁇ , - ⁇ , - ⁇ , TNF- ⁇ , - ⁇ , TGF- ⁇ , - ⁇ , NGF, and the like.
• cytokines such as IL-1, -2, -6, -12, GM-CSF, G-CSF, M-CSF, IFN- ⁇ , - ⁇ , - ⁇ , TNF- ⁇ , - ⁇ , TGF- ⁇ , - ⁇ , NGF, and the like.
• cytokines such as IL-1, -2, -6, -12, GM-CSF, G-CSF, M-CSF, IFN- ⁇ , - ⁇ , - ⁇ , TNF- ⁇ , - ⁇ , TGF- ⁇ , - ⁇ , NGF, and the like.
• the adenovirus death protein (ADP), encoded within the E3 region, is maintained (i.e., contained) in the adenovirus vector.
• the ADP gene under control of the major late promoter (MLP), appears to code for a protein (ADP) that is important in expediting host cell lysis. Tollefson et al. (1996) J. Virol. 70(4):2296; Tollefson et al. (1992) J Virol. 66(6):3633.
• MLP major late promoter
• adenoviral vectors containing the ADP gene may render the adenoviral vector more potent, making possible more effective treatment and/or a lower dosage requirement.
• the invention provides adenovirus vectors in which a first adenovirus gene is in under transcriptional control of a first heterologous cell-specific TRE and a polynucleotide sequence encoding an ADP under control of a second heterologous TRE, which is different from the first TRE but functional in the same cell as the first TRE, preferably the first adenovirus gene is essential for replication.
• a DNA sequence encoding an ADP and the amino acid sequence of an ADP are depicted in SEQ ID NO:9 and SEQ ID NO: 10, respectively.
• an ADP coding sequence is obtained preferably from Ad2 (since this is the strain in which ADP has been more fully characterized) using techniques known in the art, such as PCR.
• the Y leader (which is an important sequence for correct expression of late genes) is also obtained and ligated to the ADP coding sequence.
• the ADP coding sequence (with or without the Y leader) can then be introduced into the adenoviral genome, for example, in the E3 region (where the ADP coding sequence will be driven by the MLP).
• the ADP coding sequence could also be inserted in other locations of the adenovirus genome, such as the E4 region.
• the ADP coding sequence could be operably linked to a heterologous TRE, including, but not limited to, another viral TRE, a tissue specific TRE such as that of AFP, CEA, hKLK2, MUCl, PSE and RR.
• the present invention does not exclude adenovirus vectors containing additional genes under control of the heterologous TREs. Accordingly, the invention provides adenoviral vectors comprising a third gene under transcriptional control of a third heterologous TRE where all of the heterologous TREs are different from each other in polynucleotide sequence but all are functional in the same cell.
• the third gene is one that contributes to cytotoxicity (whether direct and/or indirect), more preferably one thatcontributes to and/or enhances cell death, and even more preferably the third gene is essential from adenovirus replication.
• the third heterologous TRE is target cell specific.
• an adenovirus vector may contain a RR-TRE, a RSE- TR ⁇ and an hKLK2-TRE, each prostate cell specific and each controlling the transcription of a different gene.
• the ability of enhancers to increase transcription of an operably linked gene is independent of its orientatoin and distance relative to the gene.
• the invention provides adenoviral vectors comprising at least an additional gene (beyond the first and the second genes) under transcriptional control of the second heterologous TR ⁇ .
• the additional gene is one that contributes to cytotoxicity (whether direct and/or indirect), more preferably one that enhances cell death, and even more preferably the third gene is essential from adenovirus replication.
• adenoviral vectors can be used in a variety of forms, including, but not limited to, naked polynucleotide (usually DNA) constructs; polynucleotide constructs complexed with agents to facilitate entry into cells, such as cationic liposomes or other compounds such as polylysine; packaged into infectious adenovirus particles (which may render the adenoviral vector(s) more immunogenic); packaged into other particulate viral forms such as HSV or AAV; complexed with agents to enhance or dampen an immune response; complexed with agents that facilitate in vivo transfection, such as DOTMATM, DOTAPTM, and polyamines.
• naked polynucleotide usually DNA
• polynucleotide constructs complexed with agents to facilitate entry into cells such as cationic liposomes or other compounds such as polylysine
• infectious adenovirus particles which may render the adenoviral vector(s) more immunogenic
• packaged into other particulate viral forms such as
• an adenoviral vector is packaged into an adenovirus
• the adenovirus itself may be selected to further enhance targeting.
• adenovirus fibers mediate primary contact with cellular receptor(s) aiding in tropism. See, e.g., Amberg et al. (1997) Virol.
• adenoviral vectors may be delivered to the target cell in a variety of ways, including, but not limited to, liposomes, general transfection methods that are well known in the art (such as calcium phosphate precipitation and electroporation), and direct injection, and intravenous infusion.
• the means of delivery will depend in large part on the particular adenoviral vector (including its form) as well as the type and location of the target cells (i.e., whether the cells are in vitro or in vivo).
• adenovirus vectors may be administered in an appropriate physiologically acceptable carrier at a dose of about 10 to about 10 14 .
• the multiplicity of infection will generally be in the range of about 0.001 to 100.
• a polynucleotide construct i.e., not packaged as a virus
• about 0.01 ⁇ g to 1000 ⁇ g of an adenoviral vector can be administered.
• the adenoviral vectors may be administered one or more times, depending upon the intended use and the immune response potential of the host or may be administered as multiple simultaneous injections. If an immune response is undesirable, the immune response may be diminished by employing a variety of immunosuppressants, so as to permit repetitive administration, without a strong immune response.
• packaged as another viral form, such as HSV an amount to be administered is based on standard knowledge about that particular virus (which is readily obtainable from, for example, published literature) and can be determined empirically.
• an adenovirus vector(s) is complexed to a hydrophilic polymer to create a masked adenovirus.
• the hydrophilic polymer is attached (covalently or non-covalently) to the capsid proteins of the adenovirus, particularly the hexon and fiber proteins.
• the adenovirus vectors of the instant invention a complexed with masking agents to create masked adenovirus vectors.
• Masked adenoviruses are advantageous due to (a) the masking of the adenovirus surface to adenovirus neutralizing antibodies or opsinins which are in circulation, and (b) increasing systemic circulation time of adenovirus particles by reduction of non-specific clearance mechanism in the body (i.e., macrophages, etc.).
• the systemic delivery of a masked adenovirus results in a longer circulation of viral particles, less immunogenicity, and increased biodistribution with a decrease in clearance by the liver and spleen.
• the invention provides an adenovirus complexed with a masking agent.
• the masking agent is PEG.
• a schematic of one method of making a masked adenovirus is depicted in Figure 13 (see also Example 7).
• a preferred embodiment is a masked adenovirus comprising an adenovirus vector(s) described herein, with a more preferred embodiment comprising a pegylated adenovirus comprising an adenovirus described herein.
• the invention also provides methods to make and use these masked adenoviruses, which are evident from the description herein.
• the masking agent may be of various molecular weights, as long as the desired complex and requisite functionality is obtained. Most masking agents obtained from commercial sources are normally polydisperse in relation to the stated molecular weight (i.e., the masking agent is supplied in a distribution of molecular weights surrounding the nominal molecular weight).
• Masking agents useful in masking adenoviruses according to the instant invention may have nominal weights of about 2000 to about 50,000; preferably, about 2500 to about 30,000; preferably, about 3000 to about 25,000; more preferably, about 5000 to about 20,000.
• the nominal molecular weight is less than about 20,000, more preferably less than about 10,000, more preferably less than about 7500, more preferably less than about 5000.
• the masking agent is PEG with a nominal molecular weight of less than about 5000 Da. Mixtures of different weight masking agents are also contemplated.
• the masking may be covalently or non-covalently attached.
• the attachment may be via electrostatic, hydrophobic, or affinity interactions.
• the masking agents used for non-covalent attachment may be modified masking agents (i.e., the masking agent is synthesized or modified to contain particular chemical moieties not normally found in the masking agent).
• Masking agents useful for electrostatic attachment to adenoviral vectors will be masking agents which contain, or have been modified or synthesized to contain, charged moieties which bind to the adenovirus surface by electrostatic interaction.
• Negatively charged masking agents include masking agents which contain phosphate groups, sulfate groups, carboxy groups, and the like.
• Quaternary amine groups are useful as positively charged moieties for electrostatic, non-covalent attachment of masking agents to adenovirus.
• Masking agents containing or modified or synthesized to contain hydrophobic groups such as lipids (e.g., phosphatidylethanolamine and the like) and other hydrophobic groups (such as phenyl groups or long alkyl chains), can be complexed to adenoviral vectors by hydrophobic interaction with stable hydrophobic regions on the virus.
• Affinity masking agents can be made using any small molecule, peptide or protein which binds to adenovirus.
• the affinity and hydrophobic moieties may be attached to the masking agent by any method known in the art, preferably by chemical crosslinking with a chemical crosslinker.
• a chemical crosslinker is preferably used to covalently bond the masking agent to the adenovirus.
• the crosslinker may be any crosslinker capable of creating a covalent linkage or bridge between the masking agent and the adenovirus.
• Direct crosslinking in which the adenovirus, masking agent and a separate crosslinker molecule are reacted, may be employed to created covalently masked adenovirus, using any chemical crosslinker known in the art which will create crosslinks between the masking agent and protein.
• Either the masking agent or the adenovirus may be modified prior to the crosslinking reaction, so that the chemical crosslinker will react with the two molecules (e.g., the masking agent may be modified to add amine groups, allowing it to be crosslinked to the adenovirus by crosslinking agents which react with amines).
• the masking agent or the adenovirus is first activated by reaction with a crosslinking agent. Unreacted crosslinker is then removed from the masking agent or adenovirus.
• the activation reaction preferably results in one or two molecules of crosslinking agent per molecule of masking agent, more preferably a single molecule of crosslinking agent per molecule of masking agent.
• the activated masking agent or adenovirus is then mixed with adenovirus (if the masking agent is activated) or masking agent (if the adenovirus is activated) under the appropriate reaction conditions to form masked adenovirus.
• the masking agent is activated, then reacted with adenovirus.
• the preferred masking agent is PEG.
• Preferred activated PEGs include, but are not limited to: nucleophilic crosslinking PEGs such as end terminal amine PEG, PEG amino acid esters, PEG hydrazine hydrochloride, thiol PEGs, and the like; carboxyl PEGs including succinate PEG, carboxymethylated PEG, PEG-propionic acid, and PEG amino acids; sulfhydryl-selective PEGs such as PEG-maleimide, PEG-orthopyridyl-disulfide and the like; heterofunctional PEGs including amines and acids PEG, NHS-maleimide PEG and NHS-vinylsulfone PEG; PEG silanes; biotin PEGs; Vinyl derivatives of PEG such as allyl PEG, PEG acrylate, PEG methacrylate, and the like; and electrophilic active PEGs, including PEG succinimidyl succinate, PEG succinimidyl succinamide, PEG suc
• Host Cells The present invention also provides host cells comprising (i.e., transformed with) the adenoviral vectors described herein.
• Both prokaryotic and eukaryotic host cells can be used as long as sequence requisite for maintenance in that host, such as appropriate replication origin(s), are present.
• selectable markers are also provided.
• Prokaryotic host include bacterial cells, for example, E. coli and mycobacteria.
• eukaryotic host cells are yeast, insect, avian, amphibian, plant and mammalian host cells.
• Suitable host cells also include any cells that produce proteins and other factors necessary for expression of the gene under control of the heterologous TREs, such factors necessary for said expression are produced naturally or recombinantly.
• Suitable host cells for the adenovirus include any eukaryotic cell type that allows function of the heterologous TREs, preferably mammalian.
• the heterologous TRE(s) used is prostate cell-specific, the cells are preferably prostate cells, for example LNCaP cells.
• the prostate cells used may or may not be producing an androgen receptor, depending on whether the promoter used is androgen-inducible.
• non-androgen receptor producing cells such as HLF, HLE, and 3T3 and the non-AR-producing prostate cancer cells PC3 and DU145 can be used, provided an androgen receptor-encoding expression vector is introduced into the cells along with the adenovirus.
• suitable host cells include any cell type that produces AFP, including but not limited to, Hep3B, HepG2, HuH7, HuHl/C12.
• Activity of a given TRE in a given cell can be assessed by measuring the level of expression of a operably-linked reporter gene using standard assays. The comparison of expression between cells in which the TRE is suspected of being functional and the control cell indicates the presence or absence of transcriptional enhancement.
• Comparisons between or among various TREs can be assessed by measuring and comparing levels of expression within a single cell line. It is understood that absolute transcriptional activity of a TRE will depend on several factors, such as the nature of the target cell, delivery mode and form of a TRE, and the coding sequence that is to be selectively transcriptionally activated. To compensate for various plasmid sizes used, activities can be expressed as relative activity per mole of transfected plasmid. Alternatively, the level of transcription (i.e., mRNA) can be measured using standard Northern analysis and hybridization techniques.
• transfection efficiencies are measured by co-transfecting a plasmid encoding a different reporter gene under control of a different TRE, such as the CMV immediate early promoter. This analysis can also indicate negative regulatory regions, i.e., silencers.
• compositions including pharmaceutical compositions, containing the adenoviral vectors described herein.
• Such compositions are useful for administration in vivo, for example, when measuring the degree of transduction and/or effectiveness of cell killing in an individual.
• these compositions further comprise a pharmaceutically acceptable excipient.
• These compositions which can comprise an effective amount of an adenoviral vector of this invention in a pharmaceutically acceptable excipient, are suitable for systemic administration to individuals in unit dosage forms, sterile parenteral solutions or suspensions, sterile nonparenteral solutions or oral solutions or suspensions, oil in water or water in oil emulsions and the like.
• compositions also include lyophilized and/or reconstituted forms of the adenoviral vectors (including those packaged as a virus, such as adenovirus) of the invention.
• kits containing an adenoviral vector of this invention can be used for diagnostic and/or monitoring purposes, preferably monitoring. Procedures using these kits can be performed by clinical laboratories, experimental laboratories, medical practitioners, or private individuals. Kits embodied by this invention allow someone to detect the presence of target cells in a suitable biological sample, such as biopsy specimens.
• kits of the invention comprise an adenoviral vector described herein in suitable packaging.
• the kit may optionally provide additional components that are useful in the procedure, including, but not limited to, buffers, developing reagents, labels, reacting surfaces, means for detection, control samples, instructions, and interpretive information.
• adenovirus vectors of the invention can be prepared using recombinant techniques that are standard in the art.
• heterologous TREs are inserted 5' to the adenoviral genes of interest, preferably one or more early genes (although late gene(s) may be used).
• Heterologous TREs can be prepared using oligonucleotide synthesis (if the sequence is known) or recombinant methods (such as PCR and/or restriction enzymes). Convenient restriction sites, either in the natural adeno-DNA sequence or introduced by methods such as PCR or site-directed mutagenesis, provide an insertion site for the heterologous TREs.
• heterologous TREs can be engineered onto the 5' and 3' ends of the heterologous TRE using standard recombinant methods, such as PCR.
• Polynucleotides used for making adenoviral vectors of this invention may be obtained using standard methods in the art such as chemical synthesis recombinant methods and/or obtained from biological sources.
• Adenovirus vectors containing all replication-essential elements, with the desired elements (e.g., EIA) under control of heterologous TREs are conveniently prepared by homologous recombination or in vitro ligation of two plasmids, one providing the left- hand portion of adenovirus and the other providing the right-hand portion.
• the resultant adenovirus vector contains at least two different heterologous TREs, with at least one of the heterologous TREs cell-specific and one adenovirus gene under control of a first heterologous TRE and a second gene under control of a second heterologous TRE.
• the two plasmids should share at least about 500 bp of sequence overlap.
• Each plasmid may be independently manipulated, followed by cotransfection in a competent host, providing complementing genes as appropriate, or the appropriate transcription factors for initiation of transcription from the heterologous TREs for propagation of the adenovirus.
• Plasmids are generally introduced into a suitable host cell such as 293 cells using appropriate means of transduction, such as cationic liposomes.
• in vitro ligation of the right and left-hand portions of the adenovirus genome can be used to construct recombinant adenovirus derivative containing all the replication-essential portions of adenovirus genome. Berkner et al. (1983) Nucleic AcidResearch 11 :6003-6020; Bridge et al. (1989) J Virol. 63:631-638.
• Plasmid pXC.l (McKinnon (1982) Gene 19:33-42) contains the wild-type left-hand end of Ad5, from Adenovirus 5 nt 22 to 5790.
• pBHGlO (Bett et al. (1994) Proc.
• the transcription start site of Ad5 El A is at nt 498 and the ATG start site of this gene's coding segment is at nt 560 in the virus genome.
• This region can be used for insertion of a heterologous TRE.
• a restriction site may be introduced by employing PCR, where the primer that is employed may be limited to the
• Ad5 genome may involve a portion of the plasmid carrying the Ad5 genomic DNA.
• the primers may use the EcoRI site in the pBR322 backbone and the Xbal site at nt 1339 of Ad5.
• a similar strategy may be used for insertion of a heterologous TRE to regulate EIB.
• the EIB promoter of Ad5 consists of a single high-affinity recognition site for Spl and a TATA box. This region extends from Ad5 nt 1636 to 1701.
• a cell-specific, heterologous TRE in this region, one can provide for cell-specific transcription of the EIB gene.
• the left-hand region modified with a cell-specific TRE regulating El A as the template for introducing a second, different cell-specific TRE to regulate EIB, the resulting adenovirus vector will be dependent upon the cell-specific transcription factors for expression of both EIA and EIB. Examples 1, 2 and 5 provide a more detailed description of how such constructs can be prepared.
• a heterologous TRE may be inserted upstream of the E2 gene to make its expression cell-specific.
• the E2 early promoter, mapping in Ad5 from 27050-27150, consists of a major and a minor transcription initiation site, the latter accounting for about
• E2 late promoter overlaps with the coding sequences of a gene encoded by the counterstrand and is therefore not amenable to genetic manipulation.
• the E2 early promoter overlaps only for a few base pairs with sequences coding for a 33-kD protein on the counterstrand.
• the Spel restriction site (Ad5 position 27082) is part of the stop codon for the above mentioned 33 kD protein and conveniently separates the major E2 early transcription initiation site and TATA-binding protein site from the upstream transcription factor biding sites E2F and ATF. Therefore, insertion of a heterologous TRE having Spel ends into the Spel site in the plus-strand would disrupt the endogenous E2 early promoter of Ad5 and should allow TRE regulated expression of E2 transcripts.
• E4 transcription start site is predominantly at nt 35609, the TATA box at nt 35638 and the first AUG/CUG of ORF 1 is at nt 35532.
• a heterologous TRE may be introduced upstream from the transcription start site.
• the co-transfection and homologous recombination are performed in W 162 cells (Weinberg et al. (1983) Proc. Natl. Acad. Sci. USA 80:5383-5386) which provide E4 proteins in trans to complement defects in synthesis of these proteins.
• Methods of packaging adenovirus polynucleotides into adenovirus particles are known in the art and are described in the Examples.
• Masked adenovirus with non- covalently attached masking agent is prepared by thoroughly and intimately mixing the adenovirus and the masking agent.
• Covalent crosslinking is achieved by mixing the reaction components under conditions appropriate to the crosslinking reagent. Chemical crosslinking protocols are well known in the art. The exact reaction conditions for any given chemical crosslinker will vary according to the chemistry of the crosslinker and the modifications (if any) to the PEG and the adenovirus, as will be apparent to one of skill in the art.
• the molar ratio of adenovirus to PEG is preferably between 1 : 1 x 10 6 and 1:1 x 10 7 , more preferably about 1 :4 x 10 6 .
• the activated PEG is preferably between 0.5 to 5 mM in the crosslinking reaction, more preferably about 2 mM.
• adenovirus in the crosslinking reaction is between 10 6 and 10 12 , more preferably about 5 x 10 9 .
• the pH of the crosslinking reaction is preferably between about 7 and 9, more preferably between about 7.5 and 8, and the reaction is preferably run for 10 to 30 minutes at a temperature ranging from about 4° C to room temperature (about 20° C).
• the masked adenovirus is separated from the reaction components.
• the separation may be accomplished by any method known to one of skill in the art, including chromatographic methods such as size exclusion chromatography, ion exchange chromatography or hydrophobic interaction chromatography, electrophoretic methods, or filtration methods such as dialysis, diafiltration or ultrafiltration.
• methods for using adenovirus vectors comprise introducing an adenovirus vector into a cell, preferably a eukaryotic cell, more preferably a mammalian cell.
• methods for using adenovirus vectors comprise introducing an adenovirus vector into a target cell, preferably a neoplastic cell. In another embodiment, methods for using adenovirus vectors comprise introducing an adenovirus vector into a prostate cell. In another embodiment, methods for using adenovirus vectors comprise introducing an adenovirus vector into a liver cell. In another embodiment, methods for using adenovirus vectors comprise introducing an adenovirus vector into a breast cancer cell. In another embodiment, methods for using adenovirus vectors comprise introducing an adenovirus vector into a colon cancer cell.
• methods for conferring selective cytotoxicity in cells which allow function of the target cell-specific TRE comprising contacting cells with an adenovirus vector described herein, such that the adenovirus vector(s) enters, i.e., transduces the cell(s).
• Cytotoxicity can be measured using standard assays in the art, such as dye exclusion, H-thymidine incorporation, and/or lysis. See Example 3, Fig. 3.
• methods for propagating an adenovirus specific for cells which allow function of the heterologous TREs, preferably eukaryotic cells, more preferably mammalian cells. These methods entail combining an adenovirus vector with mammalian cells which allow function of the heterologous TREs, whereby said adenovirus is propagated.
• Another embodiment provides methods of killing cells that allow a heterologous TRE to function comprising combining the mixture of cells with an adenovirus vector of the present invention.
• the mixture of cells is generally a mixture of cancerous cells in which the heterologous TREs are functional and normal cells, and can be an in vivo mixture or in vitro mixture.
• the invention also includes methods for detecting cells in which the heterologous TREs are functional in a biological sample. These methods are particularly useful for monitoring the clinical and/or physiological condition of an individual (i.e., mammal), whether in an experimental or clinical setting.
• cells of a biological sample are contacted with an adenovirus vector, and replication of the adenoviral vector is detected.
• a suitable biological sample is one in which target cells may be or are suspected to be present.
• a suitable clinical sample is one in which target cancerous cells are suspected to be present.
• Such cells can be obtained, for example, by needle biopsy or other surgical procedure.
• Cells to be contacted may be treated to promote assay conditions such as selective enrichment and/or solubihzation.
• target cells can be detected using in vitro assays that detect proliferation, which are standard in the art.
• standard assays include, but are not limited to, burst assays (which measure virus yields) and plaque assays (which measure infectious particles per cell).
• propagation can be detected by measuring specific adenoviral DNA replication, which are also standard assays.
• the invention also provides methods of modifying the genotype of a target cell, comprising contacting the target cell with an adenovirus vector described herein, wherein the adenoviral vector enters the cell.
• the invention further provides methods of suppressing tumor cell growth, comprising contacting a tumor cell with an adenoviral vector of the invention such that the adenoviral vector enters the tumor cell and exhibits selective cytotoxicity for the tumor cell.
• tumor cells and “tumor” refer to cells which exhibit relatively autonomous growth, so that they exhibit an aberrant growth phenotype characterized by a significant loss of control of cell proliferation. Tumor cell growth can be assessed by any means known in the art, including, but not limited to, measuring tumor size, determining whether tumor cells are proliferating using a H-thymidine incorporation assay, or counting tumor cells.
• “Suppressing” tumor cell growth means any or all of the following states: slowing, delaying, and stopping tumor growth, as well as tumor shrinkage. "Suppressing" tumor growth indicates a growth state that is curtailed when compared to growth without contact with, i.e., transfection by, an adenoviral vector described herein. See Example 4, Fig.6.
• the invention also provides methods of lowering the levels of a tumor cell marker in an individual, comprising administering to the individual an adenoviral vector of the present invention, wherein the adenoviral vector is selectively cytotoxic toward cells producing the tumor cell marker.
• Tumor cell markers include, but are not limited to, PSA, carcinoembryonic antigen and hK2.
• Methods of measuring the levels of a tumor cell marker include, but are not limited to, immunological assays, such as enzyme-linked immunosorbent assay (ELISA), using antibodies specific for the tumor cell marker.
• immunological assays such as enzyme-linked immunosorbent assay (ELISA)
• ELISA enzyme-linked immunosorbent assay
• a biological sample is obtained from the individual to be tested, and a suitable assay, such as an ELISA, is performed on the biological sample. See Example 4, Fig. 7.
• the invention also provides methods of treatment, in which an effective amount of an adenoviral vector(s) described herein is administered to an individual.
• an adenoviral vector(s) in which at least one heterologous TRE is specific for prostate cells e.g., RSE-TRE, RR-TRE, and/or hKLK2-TRE
• treatment using an adenoviral vector(s) in which at least one heterologous TRE is specific for prostate cells e.g., RSE-TRE, RR-TRE, and/or hKLK2-TRE
• individuals with prostate-associated diseases as described above, such as hype ⁇ lasia and cancer.
• individuals who are considered to be at risk for developing prostate-associated diseases such as those who have had disease which has been resected and those who have had a family history of prostate-associated diseases.
• adenoviral vector(s) of the invention Determination of suitability of administering adenoviral vector(s) of the invention will depend, inter alia, on assessable clinical parameters such as serological indications and histological examination of tissue biopsies.
• a pharmaceutical composition comprising an adenoviral vector(s) is administered.
• Pharmaceutical compositions are described above.
• the amount of adenoviral vector(s) to be administered will depend on several factors, such as route of administration, the condition of the individual, the degree of aggressiveness of the disease, the particular heterologous TREs employed, and the particular vector construct (i.e., which adenovirus genes are under heterologous TRE control).
• adenovirus is administered as a packaged adenovirus, from about 10 4 to about 10 14 , preferably from about 10 4 to about 10 12 , more preferably from about 10 4 to about 10 10 .
• a polynucleotide construct i.e., not packaged as a virus
• about 0.01 ⁇ g to about 100 ⁇ g can be administered, preferably 0.1 ⁇ g to about 500 ⁇ g, more preferably about 0.5 ⁇ g to about 200 ⁇ g.
• More than one adenoviral vector can be administered, either simultaneously or sequentially. Administrations are typically given periodically, while monitoring any response. Administration can be given, for example, intratumorally, intravenously or intraperitoneally.
• adenoviral vectors of the invention can be used alone or in conjunction with other active agents, such as chemotherapeutics, that promote the desired objective.
• active agents such as chemotherapeutics
• adenovirus vector constructs in which a first adenovirus gene is under transcriptional control of an hKLK2-TRE and a second adenovirus gene is under transcriptional control of a RSE-TRE
• hKLK2-TRE adenovirus constructs To generate hKLK2-TRE adenovirus constructs, four hKLK2-TRE fragments which contain at least the hKLK2 minimal promoter were amplified using the DNA sequence from approximately 12,000 bp lying upstream of the first exon in hKLK2 (S ⁇ Q ID NO:3) and synthetic oligonucleotides as described below. The four constructs were generated by ligating these fragments into pG ⁇ M-T vector.
• CN294 is a pG ⁇ M-T vector derivative containing an hKLK2 full promoter.
• the fragment was amplified by PCR with oligonucleotide 42.100.1 : 5 ' -GAT CAC CGG TGT CCA CGG CCA GGT GGT GC-3' (S ⁇ Q ID NO: 11) (PinAI site underlined), which is complementary to the 5 '-untranslated region (UTR) of the first exon in hKLK2, in combination with 42.100.2 (5' -GAT CAC CGG TGC TCA CGC CTG TAA TCT CAT CAC-3'; S ⁇ Q ID NO:12; PinAI site underlined). 42.100.2 corresponds to the upstream region of the hKLK2 promoter.
• CN296 is a pG ⁇ M-T vector derivative containing an hKLK2 fragment from nt -2247 to nt +33, which was amplified by PCR with oligonucleotides 42.100.1 and 42.100.3 (5'- GAT CAC CGG TGG TTT GGG ATG GCA TGG CTT TGG-3'; S ⁇ Q ID NO: 13, PinAI site underlined). 42.100.3 corresponds to a region approximately 2300 bp upstream oihKLK2.
• CN317 is a pG ⁇ M-T derivative containing the hKLK2 minimal promoter.
• a PCR fragment corresponding to the hKLK2 5'-UTR from nt -323 to nt +33 was amplified with two synthetic oligonucleotides; 42.100.1 and 43.121.1 (5'-GAT CAC CGG TAA AGA ATC AGT GAT CAT CCC AAC-3'; S ⁇ Q ID NO: 14, PinAI site underlined).
• CN310 is a pG ⁇ M-T vector derivative containing an hKLK2 full promoter and is identical to CN294 except ⁇ agI sites flank the insert.
• the fragment was amplified by PCR with oligonucleotide 42.174.1 (5'-GAT CCG GCC GTG GTG CTC ACG CCT GTA ATC-3'; S ⁇ Q ID NO:15, ⁇ agI site underlined) in combination with 42.174.2 (5'- GAT CCG GCC GTG TCC ACG GCC AGG TGG TGC AG-3'; SEQ ID NO: 16; Eagl site underlined).
• hKLK2 promoter-driven EIA Ad5 plasmid CN303 CN303 was produced by inserting the hKLK2 promoter just upstream of the EIA coding segment in a derivative of pXC-1, a plasmid containing the left hand end of the Ad5 genome, as follows.
• CN124 is a derivative of construct pXC-1 which contains the wild-type left hand end of Ad5, including both EIA and EIB (McKinnon (1982) Gene 19:33-42). CN124 also has, among other alterations, an artificial PinAI site at Ad5 nt 547 (just upstream of the EIA transcriptional start at nt 560 and the El A coding segment beginning with ATG at 610). CN124 was linearized with PinAI and dephosphorylated with calf intestinal alkaline phosphatase (New England Biolabs).
• CN294 was digested with PinAI to free the hKLK2 promoter.
• the hKLK2 promoter was then ligated into the PinAI linearized CN124, producing CN303.
• CN304 is similar to CN303 except for the hKLK2 promoter fragment is in the reverse orientation.
• construct CN303 contains the hKLK2 promoter inserted upstream of and operably linked to the EIA coding segment in the Adenovirus 5 genome.
• CN316 was produced by inserting the hKLK2 -promoter just upstream of the EIB coding segment in a derivative of pXC-1, a plasmid containing the left hand end of the Ad5 genome, as follows.
• CN124 also contains an artificial Eagl site at Ad5 nt 1682, just upstream of the EIB coding segment.
• the hKLK2 promoter was excised from CN310 with Eagl and inserted into CN124 digested with Eagl to produce CN316.
• CN316 contains the hKLK2 promoter immediately upstream of and operably linked to the EIB coding segment.
• Ad5 construct comprising an hKLK2-TRE driven EIA and a PSE-TRE driven EIB
• CN301 was generated from CN125 by inserting an hKLK2 promoter upstream of the El A gene as follows.
• CN125 is a pXC-1 derivative in which expression of the EIB gene is driven by RSE.
• a PinAI site lies upstream of the ⁇ 1A gene, whose expression is driven by its wild- type promoter.
• CN125 was created by inserting RSE as an ⁇ agI fragment from construct CN105 into the ⁇ agI site immediately upstream of the ⁇ 1B gene in CN124.
• CN105 contains the RSE region from -5322 to -3875 relative to the PSA transcription start site.
• the hKLK2-TRE fragment was freed from CN294 by PinAI digestion and ligated into
• the CN301 construct contains the hKLK2 promoter immediately upstream of and operably-linked to the ⁇ l A gene and the RSE-TR ⁇ immediately upstream of and operably- linked to the ⁇ 1B gene.
• Ad5 constructs comprising PSE-TRE driven EIA gene and hKLK2 promoter driven EIB gene (CN323)
• CN323 was constructed as follows so that the expression of ⁇ 1A is mediated by
• RSE-TR ⁇ and expression of ⁇ 1B is mediated by an hKLK2 promoter.
• CN314 is a plasmid containing a RSE-TR ⁇ fragment in pG ⁇ M-T vector. This RSE fragment was amplified from CN706, an adenoviral construct in which a RSE-TR ⁇
• S ⁇ Q ID NO:2 drives expression of the ⁇ l A transcription unit in Ad5, with two synthetic oligonucleotides: 51.10.1 (5'-CTC ATT TTC AGT CAC CGG TAA GCT TGG-3'; S ⁇ Q ID NO:17) and 51.10.2 (5'-GAG CCG CTC CGA CAC CGG TAC CTC-3'; S ⁇ Q ID NO:18).
• the RSE-TR ⁇ fragment was isolated by digesting CN314 with PinAI and ligated into PinAI digested CN316 (described above).
• the CN323 construct is a plasmid containing RSE-TRE immediately upstream of and operably-linked to the El A gene and the hKLK2 promoter immediately upstream of and operably-linked to the EIB gene.
• adenoviral constructs comprising a first adenoviral gene under transcriptional control of an hKLK2-TRE and a second adenoviral gene under transcriptional control of a PSE-TREs
• CN306 was derived from CN124 by removing the endogenous 64-nucleotide EIA promoter.
• CN421 was constructed by inserting an hKLK2-TRE (comprising an hKLK2 enhancer from nucleotides -5155 to -3387 relative to the hKLK2 gene transcription start site (nucleotides 6859 to 8627 of SEQ ID NO:3) and an hKLK2 minimal promoter as in CN379 into CN306.
• the hKLK2-TRE fragment was amplified by PCR from CN379, digested with PinAI and ligated into similarly cut CN306, to produce CN421.
• CN438 was constructed by inserting an hKLK2-TRE (comprising an hKLK2 enhancer from nucleotides -4814 to -3643 relative to the hKLK2 gene transcription start site (nucleotides 7200 to 8371 of SEQ ID NO:3) and a minimal hKLK2 promoter as in
• the enhancer fragment was amplified by PCR from CN390, digested with PinAI and ligated into similarly cut CN306, to produce CN438.
• CN321 was created from CN306 by inserting a large RSE-TRE amplified from CN96 (see US Patent No. 5,698,443; Rodriguez et al. (1997)).
• CN416 was constructed by inserting an hKLK2-TRE (comprising an hKLK2 enhancer from nucleotides -5155 to -3387 relative to the hKLK2 gene transcription start site (nucleotides 6859 to 8627 of SEQ ID NO:3) and an hKLK2 minimal promoter as in CN379 into CN321.
• the enhancer fragment was amplified by PCR from CN379, digested with Eagl and ligated into similarly cut CN321, to generate CN416.
• CN422 was constructed by inserting an hKLK2-TRE (comprising an hKLK2 enhancer from nucleotides -5155 to -3387 relative to the hKLK2 gene transcription start site (nucleotides 6859 to 8627 of SEQ ID NO:3) and an hKLK2 minimal promoter as in CN379 into CN369.
• CN369 is a derivative of CN306 in which the endogenous EIB promoter was removed.
• the hKLK2-TRE was amplified from CN379, digested with Eagl, and ligated into similarly cut CN369 to produce CN422.
• CN444 was constructed by replacing the hKLK2-TRE of CN442 with an hKLK2-TRE comprising an hKLK2 enhancer from nucleotides -4814 to -3643 relative to the hKLK2 transcription start site (nucleotides 7200 to 8371 of SEQ ID NO:3) and a minimal hKLK2 promoter, as in CN390.
• the hKLK2-TRE was amplified from CN390, digested with Eagl, and ligated into similarly cut CN369, to produce CN444.
• CN446 is similar to CN444, except that the endogenous EIB promoter was not removed.
• the hKLK2-TRE was amplified from CN390, digested with Eagl, and ligated into similarly cut CN321, to produce CN446.
• CN459 and CN460 are similar to CN444, except that each contains an hKLK2-TRE comprising an hKLK2 enhancer from nucleotides -3993 to -3643 relative to the hKLK2 transcription start site and a hKLK2 minimal promoter, as in CN396.
• CN463 was constructed by inserting an hKLK2-TRE (comprising an hKLK2 enhancer from nucleotides -4814 to -3643 relative to the hKLK2 transcription start site and a minimal hKLK2 promoter, as in CN390, into CN251.
• the hKLK2-TRE was excised from CN446 with Eagl, and ligated into similarly cut CN251, to produce CN463.
• Adenovirus containing hKLK2-TRE were generated by homologous recombination in 293 cells. Briefly, CN301 was co-transfected with BHG10 (which contains right hand end of the adenovirus genome), into 293 cells. The cells were overlaid with media, and infectious virus generated by in vivo recombination was detected by cytopathic effect and isolated. Plaque-purified stocks of an adenovirus vector, designated CN747, were established. The structure of the recombinant virus was characterized by PCR, restriction endonuclease digestion and Southern blot.
• CN747 is a full-length Ad5 with the hKLK2 promoter driving the expression of El A and a RSE-TRE driving expression of EIB.
• Virus CN754 were generated with the same approach except that the CN301 plasmid was replaced with CN323.
• CN754 is a virus whose EIA and EIB are under the control of the RSE-TRE and the hKLK2-TRE, respectively.
• Viruses CN753, CN755, CN759, CN761, CN763, CN764, CN765, CN767, CN768, CN769, CN770, CN772 and CN773 were generated using the method as described above, from the parent plasmids CN326, CN328, CN398, CN316, CN421, CN416, CN422, CN436, CN438, CN444, CN446, CN459, CN460, and CN463, respectively.
• These viral constructs are shown schematically in Figures 2 A, 2B and 2B.
• adenovirus vectors in which expression of one viral replication gene is controlled by a PSE-TRE and expression of another is controlled by a PB-TRE
• the oligonucleotides created a unique PinAI (Agel) site (A/CCGGT) or Eagl site (C/GGCCG) at both ends of the PCR fragments.
• the PCR fragments were ligated into the pGEM-T vector (Promega) to generate plasmids CN249 and CN250.
• CN256 was created using the same strategy but the PB-TRE fragment was ligated into the pCRT vector (Invitrogen); CN271 is identical to CN250 but with a Hindlll site at the 5'-end.
• the endogenous (adenoviral) TREs were not deleted; rather, in each construct, the PB-TRE was inserted between the endogenous TRE (e.g., the EIA TRE) and its respective coding segment (e.g., the EIA coding segment).
• the endogenous (Ad5) promoter-enhancer has been deleted, and the prostate-specific promoter-enhancer placed immediately upstream of an early gene.
• PB-TRE-driven EIA Ad5 plasmid (CN251) An adenovirus vector in which expression of early gene El A is under transcriptional control of PB-TRE was constructed as follows.
• CN124 was linearized with PinAI and dephosphorylated with calf intestinal alkaline phosphatase (New England Biolabs). CN249 was digested with PinAI to free the RR-TRE fragment. The RR-TRE fragment was then ligated into the PinAI-linearized CN 124, producing CN251. CN253 is similar to CN251 except for the RR-TRE is in the reverse orientation.
• construct CN251 contains the RR-TRE inserted upstream of and operably linked to the EIA coding segment in the Adenovirus 5 genome.
• the vector CN253 is similar, but the RR-TRE is in the reverse orientation.
• An adenovirus derivative in which the expression of early gene EIB is under transcriptional control of the RR-TRE was constructed as follows.
• CN124 which carries the left-end of Ad5, as described above, also contains an artificial Eagl site at Ad5 nt 1682, or just upstream of the EIB coding segment.
• TRE fragment was excised from CN250 with Eagl and inserted into CN124 digested with Eagl. This produced CN254, which contains the RR-TRE immediately upstream of and operably linked to the EIB coding segment.
• CN255 is identical to CN254, but the orientation of the RR-TRE insert is reversed.
• CN275 is the same as CN254, but with a Hindlll site at the 5'-end.
• Adenovirus vector comprising a PB-TRE driven EIA and a PSE-TRE driven EIB (CN257)
• RSE-TRE prostate specific antigen transcriptional regulatory element
• CN257 which is a plasmid containing a RR-TRE operably linked to the El A gene and a RSE-TRE operably linked to the EIB gene.
• CN258 is similar to CN257, but with the opposite orientation of the RR-TRE fragment.
• Ad5 plasmid comprising PSE-TRE driven EIA and PB-TRE driven EIB (CN273)
• An adenovirus vector was constructed in which expression of El A is mediated by a RSE-TRE and expression of EIB is mediated by a RR-TRE.
• CN143 is a pBluescript (Stratagene, La Jolla, California) derivative containing the RSE-TRE fragment. This fragment was excised with PinAI and ligated into PinAI - digested CN254.
• the final construct is a plasmid containing a RSE-TRE operably linked to the EIA gene and a RR-TRE operably linked to the EIB gene.
• CN274 is similar to CN273 except for the opposite orientation of RR-TRE.
• CN306 was derived from CN124 by removing EIA endogenous promoter of 64 nts.
• CN321 was created from CN306 with a inserting of large PSE fragment amplified from CN96.
• CN326 was derived from CN321 by inserting PB-TRE into Eagl site.
• CN321 is a plasmid containing PSE (from CN96) at the PinAI site of CN306.
• adenovirus constructs in which expression of one adenovirus replication gene is controlled by hKLK2-TRE and expression of another adenovirus replication gene is controlled by PB-TRE
• CN463 was generated from CN251 by inserting an hKLK2-TRE into the Eagl site.
• the hKLK2-TRE was excited from plasmid CN446 with Eagl, ligated into a similarly cut
• the CN463 construct is a plasmid containing a RR-TRE immediately upstream and operably linked to the El A gene and an hKLK2-TRE (comprising an hKLK2 enhancer from nucleotides -4814 to -3643 relative to the hKLK2 transcription start site and minimal hKLK2 promoter) immediately upstream and operably linked to the E 1 B gene .
• Adenoviruses that contain two heterologous TREs were generated by homologous recombination in 293 cells. Briefly, 5 ⁇ g of CN257 and 5 ⁇ g of BHGl 0, which contains the right hand end of Ad5, was co-transfected into 293 cells. The cells were overlaid with medium, and infectious virus, generated by in vivo recombination, was detected by cytopathic effect and isolated. Plaque-purified stocks of an adenovirus vector, designated CN739, were established. The structure of the recombinant virus was characterized by PCR, restriction endonuclease digestion and Southern blot. The viral genome of CN739 has the El A transcription unit of Ad5 under the control of RR-TRE while EIB is under the control of RSE-TRE.
• adenoviruses CN750, CN753, CN764, CN767, CN770, CN772, CN774, were generated with the same approach except that CN257 was replaced with CN273, CN326, CN416, CN436, CN446, CN459, CN463, respectively.
• plaque assays were performed.
• a plaque assay is an infectious quantitative assay that quantifies how efficiently a particular virus produces an infection in a cell. Plaquing efficiency was evaluated in the following cell types: prostate tumor cell lines (LNCaP, PC-3), breast normal cell line (HBL-100), breast carcinoma cell line (MCF-7), ovarian tumor cell lines (OVCAR-3, SK-OV-3), hepatocarcinoma cell lines (HepG2, SK-Hep-1), and human embryonic kidney cells (293). LNCaP cells express both androgen receptor and PSA, while the other cell lines tested do not.
• 293 cells serve as a positive control for plaquing efficiency, since this cell line expresses Ad5 EIA and EIB proteins.
• the plaque assay was performed as follows. Confluent cell monolayers were seeded in 6-well dishes eighteen hours before infection. The monolayers were infected with 10-fold serial dilutions of each virus. After infecting monolayers for four hours in serum-free media (MEM), the media was removed and replaced with a solution of 0.75%) low melting point agarose and tissue culture media. Plaques were scored two weeks after infection. CN702 has no modifications in its El region and is used as a wild type control.
• Adenovirus with heterologous TREs plaque assay data Percent of wild-type adenovirus (PFU/ml)
• CN702 100 100 100 CN706 100 25 1.5
• Tables 1-7 show the results of plaque assays performed with the adenoviral vectors described in Examples 1 and 2. The results are expressed as percent of wild-type adenovirus plaque-forming units (PFU) per ml.
• the tables show the average titer of duplicate samples for the viruses tested. The titer for a particular virus in all cell lines was normalized to its titer on 293 cells. Once the titers on a cell type were normalized to 293 cells, the normalized numbers of the recombinant viruses were compared to CN702. A ratio of less than 100 suggests that the virus tested plaques less efficiently than CN702. Conversely, a ratio greater than 100 suggests that the virus plaques more efficiently than CN702.
• hKLK2-TRE, PSE-TRE and RR- TRE engineered adenoviruses demonstrate preferential replication in prostate tumor cells. Since this carcinoma expresses androgen receptors, the RSE, hKLK2 and RR TR ⁇ s contained in the adenoviral vectors should be active in promoting the transcription of the adenovirus early genes.
• Tables 1-7 suggest that the heterologous
• TR ⁇ containing adenoviral vectors induce cytopathic effects with a slightly lower efficiency than wild type adenovirus in prostate tumor cells.
• hKLK2-TRE, PSE- TRE and RR-TR ⁇ containing adenoviruses show a dramatically lower plaquing efficiency in non-prostate tumor cells when compared to wild type.
• CN764 and CN739 produced 3,000- and 10,000-fold less plaques than wild type Ad5, respectively. The results are similar for these two viruses in HBL-100 cells, where virus replication is also severely compromised.
• adenoviral vectors containing two prostate cell specific heterologous TR ⁇ s give 10 to 100-fold (or more) less plaques in non-prostate cells that an adenoviral vector containing a single heterologous prostate cell specific TR ⁇ despite the titers of the two types of adenovirus vectors being similar in LNCaP cells.
• RSE-TR ⁇ and hKLK2-TRE CN764
• PS ⁇ -TR ⁇ and RR-TR ⁇ CN739
• adenovirus vectors give 10- to 100-fold less plaques in HBL-100 and OVCAR-3 cells than CN706, although their titers were similar to CN706 in LNCaP cells.
• adenoviruses engineered with two different prostate cell specific TR ⁇ s were significantly attenuated relative to wild-type adenovirus and CN706 in non- prostate cells, but they showed similar activity to CN706 in LNCaPs.
• adenoviruses containing two heterologous TREs demonstrated an unexpectedly high preferential replication in prostate tumor cells as compared to wild type adenovirus and to CN706, in which a RSE-TRE controls EIA. This increase in specificity is more than an additive effect of inserting a second prostate-specific TRE. Since CN739 and CN764 appeared to be the most specific viruses, they were further characterized in the following experiments.
• CPE assays were performed as follows. Cells were infected with virus at increasing multiplicities of infection (MOI) and monitored for cytopathic effect. Assays were terminated when complete cytolysis of the monolayers was observed at an MOI of 0.01 with wild-type adenovirus.
• MOI multiplicities of infection
• Assays were terminated when complete cytolysis of the monolayers was observed at an MOI of 0.01 with wild-type adenovirus.
• One primary, non-immortalized human microvascular endothelial cell line (hMVEC) was chosen to test its sensitivity to CN764 and wild-type adenovirus (CN702) infection, in vitro. As shown in Figure 3, CN702 caused complete monolayer cytolysis of hMVECs at MOIs as low as 0.01 within 10 days.
• CN764 infected hMVEC monolayers did not show significant cytopathic effects at the same time points with MOIs of 10, 1.0, 0.1 and 0.01. Cytolysis of hMVECs equivalent to that seen with wild-type adenovirus was only evident at MOIs between 100 and 1000 times as high (MOI>l 0).
• CN764 and CN739-mediated cytolysis is significantly attenuated relative to wild-type adenovirus in primary normal human cells.
• virus replication titration was carried out on PSA producing prostate tumor cells (LNCaP) and primary human microvascular endothelial cells (hMVECs). Cells were grown to 70-90%) confluence and infected with either wild-type adenovirus (CN702) or CN739, CN764, CN765, CN770 for 90 min at a MOI of 10. Fifty-five hours after infection, the virus was released from the cells by three freeze/thaw cycles, and the resulting supernatant was titered on 293 cells.
• LNCaP prostate tumor cells
• hMVECs primary human microvascular endothelial cells
• the amount of CN739 produced 56 hours after infection was normalized against the amount of wild-type virus produced in the same cell line during the same time period.
• the data, shown in Figure 4, indicate that the titers of adenovirus vectors containing two different prostate cell specific TREs were 30% of CN702 titers in LNCaPs, but were reduced to less than 1/100 those of the wild-type viruses in normal cells. These data suggest that CN764-like viruses replicate poorly in primary normal human cells, and are somewhat attenuated in prostate cancer cells.
• the efficiency and kinetics of replication of CN739, CN706 and CN702 were measured using a one-step growth curve assay in LNCaPs and hMVECs. Replicate monolayers of LNCaPs and hMVECs were infected at a MOI of 10 to obtain a synchronous infection of all the cells. Duplicate cultures were harvested at various times post-infection. The number of infectious virus was determined by plaque assay on 293 cells ( Figure 5). CN739 and CN706 grew at a similar efficiency in LNCaPs.
• CN739 grew poorly in the hMVECs, producing about 10,000- fold and 80,000-fold less infectious virus than CN706 and wild-type adenovirus, respectively.
• the one-step growth curve demonstrated that an adenovirus containing two different prostate cell specific TREs, each controlling a different adenoviral gene, grew well in prostate tumor cells but grew poorly in non-prostate endothelial cells, indicating significantly enhanced specificity for target cells.
• adenoviruses containing two different heterologous TREs Stability of the adenoviruses containing two different heterologous TREs
• the use of two different heterologous TREs in the adenovirus vectors appears to provide stability to the genome during adenoviral replication.
• CN739 and CN764 were plaque purified for three times and their DNA were examined by PCR, as well as,
• An especially useful objective in the development of target cell specific adenoviral vectors is to treat patients with neoplasia comprising the target cells.
• the prostate cell specific adenoviral vectors described above may be useful to treat patients with prostate carcinoma.
• An initial indicator of the feasibility is to test the vectors using a technique known in the art, such as testing the vectors for cytotoxicity against neoplastic cell, such as prostate carcinoma, xenografts grown subcutaneously in Balb/c nu/nu mice.
• LNCaP tumor xenografts were grown in athymic mice.
• the tumor cells were injected subcutaneously into each flank of each mouse, and after establishment of palpable tumors (mean tumor volume 300 mm 3 ), the tumors were directly injected with CsCl purified CN739 at 2.5 x 10 8 particles per mm 3 , or PBS containing 10% glycerol (vehicle) as a control. Tumor growth was then followed for 6 weeks, at which time the mean tumor volume in each group was determined and serum samples were collected for PSA analysis on day 0 and weekly thereafter.
• the serum PSA level is a widely used marker for the diagnosis and management of prostate carcinoma.
• LNCaP cells express and secrete high levels of PSA into the culture media and into circulation.
• An experiment was designed to examine the effects of treatment with CN739 on the serum PSA concentration in mice with LNCaP tumor xenografts.
• IV intravenous
• adenoviral vector of the present invention by tail vein injection, or 10 pfu of a replication defective adenovirus (CMV-LacZ) to control for nonspecific toxic effects of the virus, or with buffer used to carry the virus.
• CMV-LacZ replication defective adenovirus
• Adenovirus vectors containing heterologous TREs may be generated so as to target the adenoviral replication to a variety of neoplasia.
• cell specific TREs that may be used to control the expression of adenovirus genes so as to lead to replication of the adenovrus vectors preferentially in the target cells as compared to non-target cells.
• Cell specific adenovirus vectors are listed under a type of neoplsia for which the vectors may provide a treatment.
• adenovirus vectors may be useful in the treatment of more than one type of neoplasia because the TREs are functional in more than one type of tumor cell, as described herein.
• Schematic diagrams of exemplary adenovirus vectors are depicted in Fig. 8 (A)-(B).
• liver neoplasia specific adenovirus vectors As described above, TREs from the AFP gene have been shown to be specifically active in liver neoplasia.
• Human AFP enhancer domains A and B (included in the region - 3954 bp to -3335 bp relative to the AFP cap site) were PCR amplified from human genomic DNA using the following primers:
• the AFP promoter was amplified from -163 to +34 using the following primers:
• the PCR product was digested with Eagl and ligated into the Eagl site immediately upstream of the EIB gene in CN124 to make CN234.
• the AFP-TRE is immeadiately upstream of and operably linked to the EIB coding sequence.
• uPA promoter and the other transcription response element are amplified by PCR with Eagl sites at the ends and ligated into Eagl digested CN219, to generate CN479.
• CN479 is a construct with the AFP-TRE operably linked to El A and uPA-TRE operably linked to EIB. Similarly, uPA-TRE is engineered into CN234 at the PinAI site, to produce CN480.
• CN480 is a construct in which El A is under transcriptional control of uPA-TRE and EIB is under transcriptional control of ⁇ 4ER-TRE.
• TREs from the MUCl gene have been identified that are specifically active in breast cancer cells.
• An adenovirus vector in which expression of the EIA gene is under control of MUCl -TRE was constructed as follows.
• the MUCl -TRE region of SEQ ID NO:29 was amplified from human genomic DNA by PCR with the following primer pairs:
• the primers were constructed with BspEI ends, which are compatible with the Agel site in CN124.
• CN124 has an Agel site at Ad5 nt 547 (just upstream of the EIA transcriptional start at nt 498 and the EIA coding segment beginning with ATG at 610) and an Eagl site at Ad5 nt 1682, or just upstream of the EIB coding segment.
• the MUCl -TRE PCR product was digested with Bspl and ligated into the Agel site of CN124 to make CN226. In CN226, the MUCl-TRE is immeadiately upstream of and operably linked to the El A coding sequence.
• the MUCl -TRE was amplified from CN226 to include Eagl ends with the following primer pairs:
• the MUCl-TRE PCR product was digested with Eagl and ligated in the Eagl site CN124 to make CN292.
• the MUCl-TRE is immediately upstrem of and operably linked to the EIB gene.
• CN481 is a construct in which the MUCl-TRE is operably linkedad to the El A gene and HER-TRE is operably linked to the EIB gene.
• HER-TRE is amplified from CN481 by PCR with PinAI site at the end, and ligated into a similarly cut CN292; to produce CN482.
• CN482 is a construct in which the HER-TRE is operably linked to the El A gene and the MUCl -TRE is operably linked to the EIB gene.
• CN487 is a construct in which the MUCl -TRE is operably linked to the EIA gene and the uPA-TRE is operably linked to the EIB gene.
• CN488 is the same as CN487 except the positions of two heterologousTREs are exchanged.
• CN488 is a construct in which the uPA-TRE is operably linked to the EIA gene and the MUCl -TRE is operably linked to the EIB gene.
• CN489 is a construct in which the MUCl-TRE is operably linked to the EIA gene and the CE.4-TRE is operably linked to the EIB gene.
• CN490 is the same as
• CN489 except the positions of two heterologousTREs are exchanged.
• CN490 is a construct in which the CEA-TRE is operably linked to the El A gene and the MUCl-TRE is operably linked to the EIB gene.
• TREs from the CEA gene have been identified that are specifically active in a number of neoplasia including colon cancers.
• An adenovirus vector in which expression of the EIA gene is under control of CE4-TRE was constructed as follows.
• a TRE of the carcinoembryonic antigen (CE4-TRE), about -402 to about +69 bp relative to the transcriptional start (SEQ ID NO:7), was amplified by PCR from human genomic DNA using primers(which introduced Agel sites at the ends): 5' ATT ACC GGT AGC CAC CAC CCA GTG AG 3' (39.174B, SEQ ID NO:34) and 5' TAG ACC GGT GCT TGA GTT CCA GGA AC 3' (39.174D, SEQ ID NO:35).
• CEA-TRE PCR fragment was ligated into pGEM-T vector which had been linearized with EcoRV and designated CN265.
• the CE4-TRE was excised from CN265 by digestion with PinAI and was ligated into similarly digested CN124 to generate CN266.
• CN266 is a construct in which the CEA-TRE is operably linked to the El A gene.
• the CE.4-TRE was amplified from CN266 by PCR using primers:
• the unique restriction site Eagl was introduced by the primer pair at the ends of the PCR amplified product.
• the PCR product was ligated into pGEM-T Vector (Promega), and the resultant plasmid designated CN284.
• the Eagl CEA-TRE fragment was excised from CN284 and isolated by gel electrophoresis, and ligated into CN124 which had been cut with Eagl to make CN290.
• CN290 is a construct in which the CEA-TRE is immediately upstream of and operably linked to the EIB gene.
• a uPA-TRE is released from CN479 with Eagl and ligated into a similarly cut CN266, to produce CN483.
• CN483 is a construct in which the CE4-TRE is operably linked to the EIA gene and the uPA-TRE is operably linked to the EIB gene.
• CN484 is a construct in which the WR.4-TRE is operably linked to the El A gene and the CEA-TRE is operably linked to the EIB gene.
• CN485 is a construct in which the HER-TRE is operably linked to the El A gene and the w ⁇ 4-TRE is operably linked to the EIB gene.
• uPA-TRE is released from CN479 with Eagl and ligated to a similarly cut CN482, to produce CN485.
• CN486 is the same as CN485 except the position of two heterologous TREs are exchanged.
• CN486 is a construct in which the uPA-TRE is operably linked to the EIA gene and the HER-TRE is operably linked to the EIB gene.
• adenovirus vectors may be generated in which a third gene is under trascriptional control of a third heterologous TRE, where all the TREs are different from each other and all are functional in the same cell.
• An adenovirus vector is generated through the insertion of the RR-TRE, the RSE-
• TRE and the hKLK2-TRE in operable linkage with three genes, for example, the EIA, EIB, and E4 genes.
• These prostate cell specific TREs are amplified as described above and inserted into the adenovirus vectors as described herein.
• Fig. 9 depicts examples of such adenoviral constructs. Also depicted in Fig. 9 is an example of a construct in which three genes are controlled by three other cell specific TREs described above.
• the adenovirus construct CN781 may be useful to target liver neoplasia in which the HER-TRE is functional.
• Adenoviruses that contain multiple heterologous TREs are generated by homologous recombination in 293 cells as described above.
• An Adenovirus death protein mutant CN751 , was constructed to test whether such a construct may be more effective for cytotoxicity.
• the Adenovirus death protein (ADP) an 11.6 kD Asn-glycosylated integral membrane peptide expressed at high levels late in infection, migrates to the nuclear membrane of infected cells and affects efficient lysis of the host.
• the Adenovirus 5 (Ad5) E3 region expresses the adp gene.
• CN751 CN751 was constructed in two parts. First, an E3 deleted platform plasmid that contains Ad5 sequence 3' from the BamHI site at 21562 bp was generated. The Ad2 adp was engineered into the remainder of the E3 region of this plasmid to yield CN252. An ADP cassette is constructed using overlap PCR. The Y leader, an important sequence for correct expression of some late genes, is PCR-amplified using primers:
• the ADP coding region is PCR amplified using primers:
• the backbone of this plasmid (outside of the Ad5 sequence) contained a Pad site that needed to be removed to enable further manipulations. This was effected by digesting CN221 with Pad and polishing the ends with T4 DNA polymerase, resulting in CN246.
• CN246 was digested with Ascl and
• Avrll (to remove intact E3 region). This fragment was replaced by a similarly cut fragment derived from BHGl 1.
• the resulting plasmid, CN 247 contained a deleted E3 region and a Pad site suitable for insertion of the ADP cassette fragment (described above). Ligation of CN247 with the ADP cassette generated CN252.
• the 5' Ad5 sequence necessary for CN751 was obtained by digesting purified CN702 DNA with EcoRI and isolating the left hand fragment by gel extraction. After digesting CN252 with EcoRI, the left hand fragment of CN702 and CN252 were ligated.
• 293 cells were transfected with this ligation mixture by using the standard lipofection transfection protocol developed at Calydon, Inc. and incubated at 37°C. Ten days later, the cells were harvested, freeze-thawed three times, and the supernatant was plaqued on 293 monolayers. Individual plaques were picked and used to infect monolayers of 293 cells to grow enough virus to test. After several days, plate lysates were screened using a polymerase chain reaction (PCR) based assay to detect candidate viruses. One of the plaques that scored positive was designated CN751.
• PCR polymerase chain reaction
• CN751 Structural Characterization ofCN751
• primers 37.124.1 and 37.124.4 were used to screen candidate viruses by PCR to detect the presence of the adp cassette.
• CN751 produced an extension fragment consistent with the expected product (1065bp).
• Second, CN751 was analyzed by Southern blot. Viral DNA was purified, digested with Pad, Sa , and Acd/Xhol, and probed with a sequence homologous to the ADP coding region. The structure of CN751 matched the expected pattern.
• CN751 cytotoxicity was evaluated in LNCaP cells by measuring the accumulation of a cytosolic enzyme, lactate dehydrogenase (LDH), in the supernatant over several days.
• LDH lactate dehydrogenase
• the level of extracellular LDH correlates with the extent of cell lysis. Healthy cells release very little, if any, enzyme, whereas dead cells release large quantities.
• LDH was chosen as a marker because it is a stable protein that can be readily detected by a simple protocol.
• CN75 l's ability to cause cell death was compared to that of CN702, a vector lacking the ADP gene, and Rec700, a vector containing the ADP gene.
• Monolayers of LNCaP cells were infected at a multiplicity of infection of one with either CN702, Rec700, or CN751 and then seeded in 96 well dishes. Samples were harvested once a day from one day after infection to five days after infection and scored using Promega' s Cytotox 96 kit. This assay uses a coupled enzymatic reaction which converts a tetrazolium salt to a red formazan product that can be determined in a plate reader at 490nm.
• the amount of LDH released from CN751 infected cells at three days is two times that released from CN702 infected cells.
• the data demonstrate that adenovirus vectors with adp gene kill cells more efficiently than adenovirus vectors that lack the adp gene.
• adnovirus vectors kill cells efficiently, they must also be able to shed progeny that can infect other target cells. Viral vectors that can shed large amounts of virus might be better therapeutics than those that shed only small amounts.
• a virus yield assay was undertaken to evaluate whether CN751 can induce the efficient release of its progeny from the infected cell. A549 cells were infected at an MOI of five.
• LNCaP nude mouse xenografts were challenged with a single intratumoral dose (1 X 10 4 particles/mm 3 tumor) of either CN751 , a vector containing the ADP gene, or CN702, a vector lacking the gene.
• a third group of tumors was treated with buffer alone. The tumors were monitored weekly for six weeks and their relative volume was graphed against time. The results are shown in Figure 12. Error bars represent the standard error for each sample group.
• the objective of PEG complexation masking of the adenovirus surface is the following: 1) adenovirus neutralizing antibodies or opsinins which are in circulation, and 2) increase systemic circulation time of adenovirus particles by reduction of non-specific clearance mechanism in the body (i.e., macrophages, etc.).
• FIG. 14 depicts the pegylation of CN706 and the mobility shift of pegylated proteins.
• Lanes 1 and 2 are non-pegylated CN706 (control)
• lanes 3 through 6 are pegylated CN706 under several pH and temperature conditions.
• Lanes 3 through 6 show the appearance of a second band above the hexon proteins of CN706, most likely pegylated hexon, and the loss of the fiber protein band. Since no additional bands associated with the virus except that corresponding to the PEG-hexon protein, the pegylated fiber protein is assumed to be under one of the unpegylated proteins on the SDS gel.
• Figure 15 is an ion exchange chromatogram showing the change in surface properties of CN706.
• Pegylation of CN706 results in its earlier elution from the Q Sepharose resin used to capture the virus. This result is most likely due to PEG rendering the virus more charge neutral in appearance and hence decreasing its binding potential to the ion exchange matrix.
• a broadening of the virus' chromatogram is expected since the pegylation of CN706 occurs to different percentages.
• the infectivity of pegylated CN706 was evaluated in an in vitro plaque assay on 293 cells.
• Table 8 depicts a 5 to 10-fold reduction in plaquing efficiency of PEG-CN706 as compared to CN706. This is most likely due to pegylation masking the virus cells, decreasing the recognition and endocytosis of the viral particles.
• Table 8 Comparison of Plaquing Efficiency of CN706 and PEG-CN706. Sample Description Number of Plaques (Arbitrary Units)
• ACTCCACTGC CAAACCCAGA ATAAGGCAGC GCTCAGGATC CCGAAGGGGC ATGGCTGGGG 2100
• CTATTGCTCT CCCAAGTGAG TCTCCCAGAT ACGAGGCACT GTGCCAGCAT CAGCCTTATC 2940
• GGGGAGGAGG CAATGGACAG GCTTGAGAAC GGGGATGTGG TTGTATTTGG TTTTCTTTGG 3120
• CTGTCTCTAC TAAAAAAAAA AAAAATAGAA AAATTAGCCG GGCGTGGTGG CACACGGCAC 4740
• CTGTAATCCC AGCTACTGAG GAGGCTGAGG CAGGAGAATC ACTTGAACCC AGAAGGCAGA 4800
• TGGGTTGGGT CAGGTTTTGG TTGAGGATGA GTTGAGGATA TGCTTGGGGA CACCGGATCC 3660
• CAACAGGCCC CAGTGTGTGT TGTTCCCCTC CCTGTGTCCA TGTGTTCTCA TTGTTCAGCT 960
• AACAGTATAT AAGCATTCCC TTTTCTCCAC AGCTTTGTCA TCATGGTTTT TTTTTTTCTT 3060
• TTGTATATGT GAAAGGTCTA CTCTCATTTT CTTTCCCTCT TTCTTTCTTT CTTTCTTTTC 3900
• AGAACCTTTC CCCACTTCCC TAGCTGCAAT GTTAAACCTA GGATTTCTGT TTAATAGGTT 6480
• AAAAGCTTAG AGATGACCTC CCAGGAGCTG AATGCAAAGA CCTGGCCTCT TTGGGCAAGG 7260
• CTGTCCTCCC AAGTGAGTCT CCCAGATACG AGGCACTGTG CCAGCATCAG CTTCATCTGT 9480
• AAGGAAGTAC TTGGGACTTA GGCACATGAG ACTTTGTATT GAAAATCAAT GATTGGGGCT 11400
• GATCATCCCA ACCCCTGTTG CTGTTCATCC TGAGCCTGCC TTCTCTGGCT TTGTTCCCTA 11760
• CTCTTCTCTA GCTAGAGACT AATCAGAAAT ACATTCAGGG ATAATTATTT GAATAGACCT 720
• CTGCTCCGTA AGGCAGAATA TGGAAGGAGA TTGGAGGATG ACACAAAACC AGCATAATAT 2820

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