WO2000020608A1

WO2000020608A1 - Method of treating prostate cancer with an adenovirus expression vector encoding a prodrug enzyme

Info

Publication number: WO2000020608A1
Application number: PCT/US1999/020908
Authority: WO
Inventors: Mitchell S. Steiner
Original assignee: Genotherapeutics, Inc.
Priority date: 1998-10-02
Filing date: 1999-10-01
Publication date: 2000-04-13
Also published as: AU6387499A

Abstract

This invention provides a method of inducing cellular cytotoxicity of a tumor cell and treating a subject with cancer with a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in the E1 and E3 region of the genome and an insertion within the region of a nucleic acid encoding a β-lactamase under the control of a Rous Sarcoma Virus promoter. This invention provides a method of inducing cellular cytotoxicity of a tumor cell and treating a subject with cancer with a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in the E1 and E3 region of the genome and an insertion within the region of a nucleic acid encoding a β-lactamase under the control of a Mouse Mammary Tumor Virus promoter.

Description

METHOD OF TREATING PROSTATE CANCER WITH AN ADENOVIRUS EXPRESSION VECTOR ENCODING A PRODRUG ENZYME

FIELD OF INVENTION

This invention provides a gene therapy method of inducing cellular cytotoxicity of a tumor cell, and treating a subject with cancer using an adenovirus expression vector having a β- 10 lactamase gene in combination with aprodrug conjugated to atoxic agent. This invention provides for adenovirus expression vectors and pharmaceutical compositions.

BACKGROUND OF THE INVENTION

Cancer is one of the most important public health problems in the United States and

15 around the world. The incidence of cancer continues to rise as more of the population survives heart disease, strokes, and other diseases with improvements in medical care. Data collected by the US Bureau of the Census and the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program have predicted 1,382,400 new cases of invasive cancer in the United States this year. Among women, the three

20 most commonly diagnosed cancers are breast, lung and bronchus, and colon and rectum. Breast cancer alone will account for 30% of the new cancers in women. In men, the three most common cancers are prostate, lung and bronchus, and colon and rectum. Prostate cancer will account for 43% of new cancers. About 560,000 Americans will die of cancer-more than 1,500 people a day. Unfortunately, the number of deaths have

25 continued to rise. In women, cancers of the lung and bronchus, breast, and colon and rectum will account for over half of all cancer deaths. In men, cancer of the lung and bronchus, prostate, and colon andrectum will account formost of the deaths. Worldwide, about 6.5 million people are newly diagnosed with cancer each year. According to the SEER program, the incidence rates for all cancers combined increased between 1973-

30 1991 by 31.5%) in men and l3.6% inwomen, Moreover, the mortality rate for the same period increased by 6,9%.

- l - The costs of cancer care have been significant. The NCI has estimated the overall annual cost for cancer care in the United States at 107 billion dollars, of which 37 billion dollars is spent on direct medical costs, 11 billion dollars on morbidity costs, and 59 billion dollars on mortality costs. The costs for cancer care will continue to rise exponentially, as a larger sector of the United States population is composed of aging individuals.

The current armamentarium against cancer has been essentially unchanged over the past century and includes surgery, chemotherapy, and radiation. Although there have been a few significant successes such as surgery for localized cancer, chemotherapy and radiation for certain leukemias and germ cell tumors, in the maj ority of cancer victims there remains no cure for their disease. Unfortunately, while surgical therapies may be effective, they may leave the patient severely and permanently disfigured. Either chemotherapy or radiation therapy are also fraught with toxicities that may be life threatening and limit their effectiveness. In fact, a major financial cost is incurred to ameliorate the side effects of surgery, chemotherapy, and radiation therapy. A newer modality, immune-therapy, has been available for over 15 years has gained only H ited clinical acceptance because of inconsistent treatment outcomes. As a consequence, there is a desperate need to find more effective and less toxic therapy against cancer. Since cancer is a product of accumulated inherited and acquired genetic mutations, then therapies like gene therapy offer for the first time a real potential for cure. Gene therapy to date has been associated with few minor side affects and may prove to be the most effective and least toxic way to treat cancer and other genetic diseases.

Currently there is no effective chemotherapeutic agent against advanced cancer. It is not that chemotherapy drugs themselves cannot kill advanced cancer cells, as cancer cells in culture can be completely eliminated if the drug concentration is high enough, The problem is that the dose necessary to achieve cell death in culture is usually not attainable in the patient without unacceptable toxicity and even death. One alternative approach that allows for high levels of drugs locally, but low blood levels of the anticancer drug, is by suicide gene therapy. Conceptually, suicide gene therapy introduces genes into cancer cells that encode for enzymes that are capable of converting inactive drugs into active, cancer killing drugs. Moreover, if prostate specific promoters are coupled to these prodrug enzyme genes then only prostate cells will be capable of producing the prodrug enzyme. In essence, the cancer cells will, by acting as their own factories to activate chemotherapy agents, commit suicide,

β-lactamases are a family of bacterial enzymes that cleave penicillins and cephalosporins into inactive forms (Richmond et al. 1973; Ambler 1980; Page 1987; Matagne et al. 1990) , β-lactamase enzyme inactivates these antibiotics by hydrolyzing the β-lactam bond which is common to all penicillin and cephalosporin derivatives (Christensen et al. 1990) . Because of the clinical importance of antibiotic resistance, much is known about the 3-D structure, mechanisms, optimal substrates, and inhibitors of β-lactamases (Page 1987; A bler 1980; Matagne et al. 1990). The wild typeEscherichia colt plasmid coded 29 Kd β-lactamase, Type I (E.C. 3.5.2.6) (also known as penicillin amido-β-lactamhydrolase, Amp^r ,TEM- 1 , R7268 Plasmid Rl , Plasmid R6K) was first isolated and described in 1965 (Sutcliffe 1978; Sutcliffe 1979; Bolivar 1977; Ambler 1980; Ambler etal. 1978;Dattaøt al. 1965). This enzyme has ammo acid homology with β-lactamases isolated from gram positive bacteria (Staphylococcus a reus, Bacillus licheniformis, saάBacill s cereus) and other gram negative bacteria (Salmonella paratyphi B). This particular β-lactamase is found on most cloning vectors and is proficient at degrading ampicillin (Sutcliffe 1 79; Prentlci etfl . 1982).

The use of β-lactamase as a prodrug enzyme to bring about prodrug cleavage and release of an active anticancer agent is advantageous for many reasons: (1) High turnover rates with rates that approach me ultimate diffusion-controlled limit (Christensen et al. 1 90;) (2) Broad substrate specificity with the ability to effect the release of a wide range of mechanistically distinct prodrug chemotherapeutic agents (Kerr et al. 1 95). A variety of cephalosporin and anticancer drugs can and have been already synthesized including phenylenedi amine mustard (Vrudhul etα/. 1993; Svenssoneta/. 1992; Alexander etal. 1991), doxorubicin (Svensson et al 1995; Meyer et al. 1993; Rodrigues et al. 1995a; Hudyma et al. 1993), platinum complexes (Hanessian et al. 1995), A vinca alkaloid (Meyer et al. 1993), and taxol (Rodrigues et al. 1995b) all have been appended to cephalosporin forming products that are a substrate for β-lactamase (Kerr et al. 1995). (3) There is no human counterpart to this enzyme, thus where the gene is targeted by gene therapy will be the only tissue to produce β-lactaraase; and (4) Different anticancer agents with different mechanisms of action can be attached to the cephalosporin linker to circumvent multiple drug or cross resistance.

SUMMARY OF THE INVENTION

This invention provides a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an ^β-lactamase under the control of a Rous Sarcoma Virus promoter.

This invention provides a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Mouse Mammary Tumor Virus promoter.

This invention provides apharmaceutical composition comprising the replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Rous Sarcoma Virus promoter and a suitable diluent or carrier.

This invention provides a harmaceutical composition comprising the reputation-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Mouse Mammary Tumor Virus promoter and a suitable diluent or carrier.

This invention provides a method of inducing cellular cytotoxicity of a tumor cell, comprising the steps of introducing into the tumor cell a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Rous Sarcoma Virus promoter; and a prodrug having an active site which is masked by ^β-lactamase, whereby a functional β- lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby inducing cellular cytotoxicity of the tumor cell.

This invention provides a method of inducing cellular cytotoxicity of a tumor cell, comprising the steps of introducing into the tumor cell a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Mouse Mammary Tumor Virus promoter; and aprodrug having an active site which is masked by β-lactamase, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to Ihe cells, thereby inducing cellular cytotoxicity of the tumor cell,

This invention provides a method of treating a subject with cancer, comprising the steps of administering to the subject a: 1) pharmaceutical composition comprising an effective amount of areplication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a promoter and a suitable diluent or carrier; and 2) a pharmaceutical composition comprising an effective amount of a prodrug having an active site which is masked by β- lactamase and a diluent or carrier, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby treating the subject with cancer.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1. Structure of the AdSRSVβ-lactamase vector. The nucleic acid sequence of Regions A and B are set forth iα Figure 10. Figure 2. Structure of the Ad5MMTVβ-lactamase vector. The nucleic acid sequence of Regions A and B are set forth in Figure 11.

Figures 3A-3B. In vitro transduction of PPC-1 cells by AdSRSVLacZ or

AdδMMTVLacZ. PPC-1 were transduced by either Ad5RSVLacZ or Ad5MMTVLacZ. Mixture incubated at 37°C for 50 hrs followed by X-gal staining, Shown are X-gal staining of PPC-1 cells transduced by Ad5RSVlacZ, moi = 100 (A) and Ad5MMTVlacZ, moi - 1,000 (B). Note that the promoter activity for RSV appeared to be 10 times greater than that for MMTV.

Figure 4. Activity of RSV and MMTV promoters in Ad-lacZ vectors. PPC-1 cells were transduced by various Ad-lacZ and incubated at 37°C for 50 h followed by X-gal staining, The percent of blue cells was determined by directly counting the number of blue cells per high powered field. Five different microscopic high powered fields were obtained and averaged at each moi.

Figure 5. β-galactosidase enzymatic activity of RSV promoter. PPC-1 cells were transduced by Ad5RSVlacZ and incubated at 37°C for 50 h. The cell extracts were harvested and the β-galactosidase activity (units/mgprotein) was evaluated by a colorimetric β-gal assay (see METHODS).

Figure d. β-galactosidase enzymatic activity of MMTV promoter. PPC-1 cells were transduced by AdSMMTVlacZ and incubated at 37°C for 50 h. The cell extracts were harvested and the β-galactosidase activity (units/mg protein) was evaluated by a colorimetric β-gal assay (see METHODS). Figures 7A-7B.

In vivo transduction efficiency of adenoviral vectors in DU145 xenograft tumors. Xenograft tumors were establishedby subcutaneously injecting cancer cells into the flanks of nude mice. When tumors reached 50 mm³ average volume, Ad5RSVlacZ was injected directly into the tumor. Tumors were harvested at 72 h. X-gal staining of representative tumors transduced by Ad5RSVlacZ at different doses are shown: (A) Ad5RSVLacZ 1X10⁹ pfu, and (B) AdSRSVLacZ 1X10⁹ pfu. The untreated control prostate tumors did not show any endogenous X-gal staining.

Figure 8. β-lactamase RT PCR. PC3 cells were transduced by Ad5MMTVβ- lactamase at moi of 200 in medium containing 1 μM Dex for 72 h. Reverse transcriptase reaction was carried out using 1 μg total RNA, An aliquot of the RT mixture was subsequently used for the PCR reaction,

The primers were specific for β-lactamase coding sequence and resulted in a 365 bp PCR amplification fragment. Primer 1 was 5' CCGTGTCGCCCTTATTCCC3 ' and Primer 2 was 5'CTCATGGTTATGGCAGCACTGC3', Lanes 1 and 7 contain lOObp DNA Ladder; Lane 2- control plasmid Ad5MMTVβ-lactamase; Lanes 3 and 4 subjected to β-lactamase RT PCR with an expected PCR product of 365 bp; and Lanes 5 and 6 subjected to β-microglobulin RT PCR with an expected PCR product of 536 bp. β2 microglobulin used to assess quality of total RNA.

Figure 9. Cytotoxicity of adenoviral β-lactamase in combination with TCM, a cephalosporin conjugated nitrogen mustard. PPC-1 cells were plated in 96-well microtiter plates at a density of 2,000 cells/well and incubated at 37°C. The cells were untreated or transduced with control virus Ad5RSVlacZ (moi=200), or Ad5MMTVβ-lactamase (moi=200). Cells were treated with increasing concentrations of TCM (0-70 μM) for 2 days at 37°C. ³H-thymidine (1 μCi/well) (ICN) was added to the cells for the final 18 h of incubation. Cells were then harvested onto filter paper using a 12-well harvester. Filter discs were removed from the harvester and placed in glass vials containing 5 ml ofEcoLite Plus™ scintillation cocktail (ICNBiomedical, CostaMesa, CA). Radioactivity was counted in a liquid scintillation counter (Model L56800, Beckman Instruments Inc., Fullerton, CA). Experiment was done in duplicate, S.E.M. error bars are smaller than the line symbols.

Figures 10A-10B. Nucleic acid sequence of Regions A and B of Figure 1 ,

Figures 11A-11B.

Nucleic acid sequence of Regions A and B of Figure 2.

DETAILED DESCRIPTION OF THE INVENTION This invention provides a gene therapy delivery system, specifically, an adenoviral type 5 vector which has an El and E3 deletion. Subcloned into the El site is a promoter-β- lactamase cassette. The promoter is either a Rous simian virus (RSV) or Mouse mammary tumor virus (MMTV). The isozyme of β-lactamase is type I (E.C. 3.5.2,6). The RSV promoter is nonspecific and is active in all ma malian cells, whereas the MMTV promoter is selective and only active in breast or prostate cells. The Ad5RSVβ-lactamase and AdSMMTVβ-lactamase vectors as demonstrated herein transduce cancer cells with β-lactamase gene and to express a functional β-lactamase prodrug enzyme. Moreover, the cytotoxic effects conferred by this transferred β-lactamase in cancers treated with cephalosporin prodrug conjugate.

The results demonstrated herein, demonstrate the use β-lactamase prodrug enzyme's in human gene therapy in combination with cephalosporin conjugated prodrugs. The use of the β-lactamase enzyme for therapy, however, is not unique as many studies have explored the use of monoclonal antibodies conjugated to β-lactamase (derived from Enterobacter cloacae) against cancer (Kerr et al. 1995; Meyer et al. 1993; Rodrigues et al 1995a; Georgopapadakou et al. 1994; Hudyma et α/. 1993; Svensson etfl/. 1992; Vrudhula et al 1993; Alexander etal. 1991; Hanessian etal 1993; Rodrigues etal. 1995b; Svensson etal. 1994; Vmdhula eta/. 1995). Unfortunately, this approach depends on the systemic administration of monoclonal antibodies to target the cancer cells. Once at the site, the cephalosporin conjugated prodrug is also given systemically, Since the β-lactamase is a nonmammalian foreign protein, the humoral system of the host may clear the antibody from the blood stream or directly inactivate the enzyme, Therefore, the immune system becomes an enemy of this therapy (Kerr et al 1995; Meyer et al. 1993; Rodrigues et al. 1995a; Georgopapadalcou et al. 1994; Hudyma et al. 1993; Svensson et al. 1992; Vrudhula et al. 1993; Alexander et al 1991; Hanessian et al. 1993; Rodrigues et al. 1995b; Svensson et al. 1994; Vrudhula et al. 1 95).

The use of the wildtype β-lactamase gene, type I for gene therapy using adenoviral vectors is unique. The nonobvious recombination of wildtype β-lactamase and a mammalian promoter into an El and E3 adenoviral type 5 vector had an unanticipated and dramatic effect on the ability of cancer cells to produce β-lactamase. By genetically transferring the β-lactamase gene into cancer cells, the local intracellular concentration of β-lactamase was markedly higher than what could be achieved by systemic administration of monoclonal antibodies. The cancer cell could continue to produce intracellular β-lactamase which is available for β-lactam cleavage, whereas the extracellularbound monoclonal antibody β- lactamase conjugates would be quickly inactivated by nonspecific proteases at the surface or the antigen-monoclonal complex becomes endocytosed and degraded (Kerr et al. 1995; Meyer etal 1993; Rodrigues etal. 1995a; Georgopapadakouetα/. 1994; Hudyma etal. 1993; Svensson etal. 1992; Vrudhula etal 1993; Alexander etal 1991; Hanessian et al. 1993; Rodrigues et al. 1995b; Svensson et al. 1994; Vrudhula et al 1995). Moreover, the jmmunogenicity of the adenoviral and β-lactamase proteins will enhance the cytotoxicity of the gene therapy in combination of cephalosporin conjugated prodrug approach.

Although Moore et al. presented an abstract in 1 97 suggesting that β-lactamase may be used as a prodrug enzyme gene, they actually presented studies that used a different gene that was a genetically modified β-lactamase gene and not the wild type β-lactamase gene as shown in the study (Moore et al .1 97). The genetically altered β-lactamase enzyme gene had DNA sequences added so that the resulting protein was either secreted or membrane bound (Moore et al. 1997). The functional consequences of this genetic alteration may impact the utility of this gene clinically. The abstract by Moore et al. showed a series of experiments using mammalian expressionplasmids in vitro and in vivo using not only the genetically modified version of β-lactamase, but also carboxypeptidase A andpenicillin G amidase. Themethod of gene delivery and efficiency were not reported (Moore et al 1997). It should also be emphasized that there are numerous types and classes of β-lactamases with distinct DNA sequences that are made by different bacteria (Christensen et al 1990; Matagne et al. 1990; Page et al. 1987; Ambler 1980). Moreover, there are enzymatic functional differences between these types of β-lactamases which require choosing the appropriate β-lactamase and optimizing its activity for use in gene therapy (Page 1987; Matagne et al. 1990). Thus, the use of the wildtype β- lactamase, type 1 , a specific β-lactamase with distinct enzymatic characteristics, whichhas been combined in a nonobvious way with a mammalian expression promoter and replication deficient adenoviral genome for human gene therapy is a unique concept, Moreover, it was unanticipated that a bacterial enzyme could be both expressed and demonstrate activity in a mammalian cell as shown in the current results herein.

This invention provides a repUcation-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an E 1 and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Rous Sarcoma Virus promoter.

This invention provides for β-lactamase and any allelic variants, analog, fragments, isoenzy es, mutants, and variants thereof and both sense and antisense strands which functionally acts when expressed by a vector so as to catalyze a prodrug, such as by example cephalosporin, conguated to a toxic agent to activate the prodrug into an agent toxic to the cells and thereby inducing cellular cytotoxicity of the cell. In the preferred embodiment the β-lactamase is Escherichi coli β-lactamase isoenzyme type 1 (E,C, 3,5.2.6). In one embodiment the β-lactamase enzyme is encoded by the nucleic acid sequence as set forth within Figure 10A. (SEQ ID NO: 1).

The nucleic acid encoding β-lactamase, RSV or MMTV include RNA, cDNA, genomic DNA, fragments, isoenzymes, variants, mutants, alleles, synthetic forms, both sense and antisense strands, and may be chemically or biochemically modified or may contain non-natural or derivatizednucleotide bases, as will be readily appreciated by those skilled in the art. Such modifications include, for example, labels, methylation, substitution of one or more of the naturally occurring nucleotides with an analog, intermicleotide modifications such as uncharged linkages (e.g., methyl phosphonates, phosphotriesters, pbosphoamidates, carbamates, etc.), charged linkages (e.g., phosphorothioates, phosphorodithioates, etc.), pendent moieties (e.g., polypeptides), intercalators (e.g., acridine,psoralen, etc.), chelators, alkylators, and modified linkages (e.g., alpha anomeric nucleic acids, etc.), Also included are synthetic molecules that mimic nucleotides in their ability to bind to a designated sequence via hydrogen bonding and other chemical interactions. Such molecules are known in the art and include, for example, those in which peptide linkages substitute for phosphate linkages in the backbone of the molecule, substantially homologous to primary structural sequence but which include, e.g., in vivo or in vitro chemical and biochemical modifications or which incorporate unusual amino acids. The nucleic acid may be modified, Such modifications include, for example, acetylation, carboxylation, phosphorylation, glycosylation, ubiquitination, labeling, e.g., with radionuclides, and various enzymatic modifications, as will be readily appreciated by those well skilled in the art. A variety of methods for labeling polypeptides and of substituents or labels useful for such purposes are well known in the art, and include radioactive isotopes such as sup ³²P, ligands which bind to labeled antiligands (e.g., antibodies), fluorophores, chemiluminescent agents, enzymes, and antiligands which can serve as specific binding pair members for a labeled ligand. The choice of label depends on the sensitivity required, ease of conjugation with the primer, stability requirements, and available instrumentation. Methods of labeling polypeptides are well known in the art. See, e.g., Sambrook et al., 1989 or Ausubel et al., 1992.

Mutations can be made in a nucleic acid encoding β-lactamase, such that a particular codon is changed to a codon which codes for a different amino acid but the function is maintained. Such a mutation is generally made by making the fewest nucleotide changes possible. A substitution mutation of this sort can be made to change an amino acid in the resulting protein in a non-conservative manner (i. e., by changing the codon from an amino acid belonging to a grouping of amino acids having a particular size or characteristic to an amino acid belonging to another grouping) or in a conservative manner (i.e., by changing the codon from an amino acid belonging to a grouping of amino acids having a particular size or characteristic to an amino acid belonging to the same grouping). Such a conservative change generally leads to less change in the structure and function of the resulting protein. A non-conservative change is more likely to alter the structure, activity or function of the resulting protein. The present invention should be considered to include sequences containing conservative changes which do not significantly alter the activity or binding characteristics of the resulting protein. Substitutes for an amino acid within the sequence may be selected from other members of the class to which the amino acid belongs. For example, the nonpolar (hydrophobic) amino acids include alanine, leucine, isoleucine, vaJine, proline, phenylalanine, tryptophan and methionine. Amino acids containing aromatic ring structures are phenylalanine, tryptophan, and tyrosine. The polar neutral amino acids include glycine, serine, threonine, cysteine, tyrosine, asparagine, and glutamine. The positively charged (basic) amino acids include arginine, lysine and histidine, The negatively charged (acidic) amino acids include aspartic acid and glutamic acid. Such alterations will not be expected to affect apparent molecular weight as determined by polyacrylamide gel electrophoresis, or isoelectric point.

Particularly preferred substitutions are: - Lys for Arg and vice versa such that a positive charge may be maintained; - Glu for Asp and vice versa such that a negative charge may be maintained; - Ser for Thr such that a free -OH can be maintained; and

- Gin for Asn such that a free NH^ can be maintained.

Synthetic DNA sequences allow convenient construction of genes which will express analogs or "muteins" . A general method for site-specific incorporation of unnatural amino acids into proteins is described in oren, et al. Science, 244:182-188 (April 1989), This method may be used to create analogs with unnatural amino acids,

In accordance with the present invention there may be employed conventional molecular biology, microbiology, and recombinant DNA techniques within the skill of the art. Such techniques are explained fully in the literature. See, e.g., Sambrook et al, "Molecular Cloning: A Laboratory Manual" (1989); "Current Protocols in Molecular Biology" Volumes I-IH [Ausubel, R. M., ed. (1994)]; "Cell Biology: A Laboratory Handbook" Volumes I-III [J. E. Celis, ed. (1994))]; "Current Protocols inhnmunology" Volumes I-EII [Coligan, J. E._s ed, (1994)]; "Oligonucleotide Synthesis" (M.J, Gait ed. 1984); "Nucleic Acid Hybridization" [B.D. Hames & SJ. Higgins eds. (1985)]; "Transcription And Translation" [B.D. Hames & SJ. Higgins, eds. (1984)]; "Animal Cell Culture" [R.I. Freshney, ed. (1986)]; "Immobilized Cells And Enzymes" URL Press, (1986)]; B. Perbal, "A Practical Guide To Molecular Cloning" (1984).

In one embodiment the Rous Sarcoma Virus promoter includes any any allelic variants, fragments, analog, isoenzymes, mutants, and variants thereof. In another embodiment the Rous Sarcoma Virus promoter has the a nucleic acid sequence as set forth in SEQ ID NO. 2. The nucleic acid may be cDNA or genomic DNA. Further the vector may comprise a polyadenylation signal, such as an SV40 polyadenylation signal. In another embodiment the vector may comprise a selectable marker. Examples of selectable markers include but are not limited to beta galactosidase or beta lactamase.

As defined herein the "Rous Sarcoma Virus promoter" has the following sequence: CGATGTACGGGCCAGATATACGCGTATCTGAGGGGACTAGGGTGTGTTTAGG

CGAAAAGCGGGGCTTCGGTTGTACGCGGTTAGGAGTCCCC TCAGGATATAGTAGTTTCGC TTTTGCATAGCCAGGGGGAAATGTAGTCTTATGCAATACACTTGTAGTCTTGCAACATGGT AACGATGAGTTAGCAACATGCCTTACAAGGAGAGAAAAAGCACCGTGCATGCCGATTGG TGGAAGTAAGGTGGTACGATCGTGCCTTATTAGGAAGGCAACAGACAGGTCTGACATGGA TTGGACGAACCACTGAATTCCGCATTGCAGAGATAATTGTATTTAAGTGCCTAGCTCGAT ACAATAAACG CCATTTGACCATTCACCACA TTGGTGTGCA CCTCC (SEQ ID NO: 2).

In one embodiment the Mouse Mammary Tumor Virus (MMTV) promoter includes any any allelic variants, fragments, analog, isoenzymes, mutants, and variants thereof. In another embodiment the Mouse Mammary Tumor Virus promoter has the a nucleic acid sequence as set forth in Figure 11 A. The nucleic acid may be cDNA or genomic DNA. Further the vector may comprise a polyadenylation signal, such as an SV40 polyadenylation signal. In another embodiment the vector may comprise a selectable marker. Examples of selectable markers include but are not limited to beta galactosidase or beta lactamase.

As demonstrated herein, the adenoviral vectors containing the RSV and MMTV were specific. Prostate and non-prostate cells were transduced with either AdSMMTVLacZ or Ad5RS VLacZ. β-Gal expression was determined by X-gal staining. To differentiate the potential involvement of endogenous hormone and glucocorticoid to the activation of promoter, the cells transduced by Ad5MMTVlacZ were treated with or without with Dex. As shown in Table 1, in general, MMTV prostate-specific promoters effectively expressed lacZ transgene in all the prostate-derived cells, but not in non-prostate cells. MMTV promoter (Ad5MMTVIacZ) activated lacZ expression in all the cells in the presence of its inducer Dex (Table 1), which was not surprising because MMTV promoter is used as an inducible promoter in general. In the absence of Dex, MMTV promoter only activated lacZ expression in three out of seven prostate cell lines, and the presence of Dex increased the lacZ expression dramatically. In addition, MMTV promoter was active in MCF-7 breast cancer cells even in the absence of Dex. These results indicated that MMTV promoter can be selectively activated in both prostate and breast cells and its activity is inducible by Dex. The vectors were made as follows: β-lactamase gene (ampicillin resistant gene) was released from plasmid pRl4.BA, a derivative of pBR322 by Bsp HI digestion. The 966 bp β-lactamase cDNA was used to replace lacZ gene in adenoviral shuttle vector pAd5MMWlacZ (Steineret<z/. 1998) to form pAd5MMTVβ-lactamase. Recombinant adenovirus Ad5MMTVβ-lactamase was generated via in vitro recombination in 293 cells by cotransfection of p JM17, an adenoviral genome plasmid, by calcium phosphate method (Kingston 1993), and cells were maintained in plaque overlay mixture (Graham et al. 1991). Plaques usually appeared in 10 to 12 days, Individual plaques were screened by PCR using one primer specific for MMTV LTR (5'GCGGAACGGACTCACCATAG3 ') and th e other primer sp ecifi c for β -lactam ase gene (5'CTCATGGTTATGGCAGCACTGC3'). PCR was performed in a 50-μl volume containing DNA from one plaque, 2 mM MgCl₂, 50 mM KCl, 0.2 mM each of dNTPs, 20 mM Tris-HCl (pH 8.4), 1 μM each of the primers, and 2.5 units of DNA Taq polymerase (Gibco BRL, Gaithersburg, MD). The reaction was carried out at 95°C for 5 min; 30 cycles at 95°C for 1 min; 58°C for 1 min; and 72°C for 1 min. This was followed by an extension period of 72°C for 10 min.

To obtain adenovirus: 15 cm plates with 293 cells were set up wich used 30 15 cm plates per production. When the cells are 70-80% confluent they are ready to be infected with adenovirus. The infection media is D2 (DMEM with 2% heat inactivated fetal calf serum). Generally, 1 μl of adenovirus stock per 15 cm plate was used. The virus is generally at a titre of 10¹⁰ p.f,u./ml while there are approximately 10⁷ p.f,u./plate, Therefore, the M.O.I. (multiplicity of infection) is 1. Thaw the adenovirus immediately before use and dilute such that there is lμl of the adenovirus preparation per 5 ml of D2. Remove the media from the plates and add 5 mis of infection media containing the adenovirus. Incubate plates in a humidified atmosphere for 1.5 hours at 37°C, 5% CO₂. Plates should be very slowly and gently rocked every 15 min so that the media covers all parts of the plate. After 90 min, add 20 ml of D10 (DMEM with 10% heat inactivated fetal calf serum, 2mM glutamine) to each plate and incubate at 37 °C. The cells are ready to harvest when they show cytopathic effect (CPE has a rounded appearance) and start to detach from the plate. The cells will also appear as "grape-like clusters". This rounding of cells begins after approximately 24 hours of infection and is fully developed after 36-48 hours, depending upon the initial amount of virus added. Within this time range, the cells should be harvested. If CPE is evident before 24 hours, the CPE could be due to the effect of viral proteins. Detach the cells by pipetting fluid and cells up and down using a 25 ml pipet (collect all cells because virus is mostly intracellular) and collect in 50 ml disposable polypropylene tubes. The cells are collected by centrifugation (table top centrifuge) at 1,500 rpm for 10 min at 4°C. Resuspend the pelleted cells in a total of 5 ml of the supernatant for every 20 plates and transfer the resuspended cells to 2059 Falcon tubes. Treat the remaining supernatant with Clorox before discarding down the sink as it is a biohazard, Freeze/thaw the cells 5X in order to lyse the cells and release the virus, vortexing between each freeze/thaw cycle. Use dry ice and a 37 °C water-bath to cycle through freezing and thawing. Remove cell debris from crude viral lysate by centrifugation using either of the two procedures indicated below: for 2059 Falcon tubes, they can be centrifuged, using adapters, at 7,000 rpm in a Sorvall HS4 rotor at 4°C for 5 min or (b) for Beckman SW40 ultracentrifuge rotor, Spin at 7,000 rpm at 4 °C for 5 min, Recover the viral supernatant and bring the volume to 5.0 ml ( for SW 41) or 5.2 ml (for SW 40) with sterile phosphate buffered saline (PBS). To purify the virus, prepare ultra-clear SW 40 or SW41 tubes (Beckman) by soaking the tubes in 95% ETOH followed by sterile H₂O or PBS and remove all the liquid. The first ultracentrifugation will involve pelleting of the adenovirus onto a CsCl cushion. D ending on the rotor used, the cushions are to be made as indicated below. The different density CsCl solutions can be made using PBS. It is easier to use ultra-clear tubes for the remaining centrifugation steps, as it is easier to view the adenoviral band.

Component SW41 SW40 SW28

CsCl (density 1.25g ml) 2.5ml 3.0ml 9.0ml

CsCl (density 1.40g/ml) 2.5ml 3.0ml 9.0ml

Viral lysate 4.25ml 5.0ml 15ml

The CsCl cushions are made by placing the lower density CsCl solution (density of 1.2 g ml) in the centrifuge tube first, then the higher density and finally the viral lysate which sits on top. The CsCl solutions are made in 1 OmM TRIS-HCL pH 7.4, lmM MgCl₂ or PBS as follows:

Density Amount of solid CsCl Volume of solution 1.25 27 73 ml

1.33 34 g 66 ml

1.40 39 g 61 ml

The density can be checked by weighing 1 ml of the CsCl solution.

Overlay the cleared viral lysate from step 12 using a sterile 2.5 ml pipet. This is accurate enough to ensure that the tubes are balanced. Alternatively, the weight of each tube can be determined and the tubes can be balanced. The tubes are then centrifuged as follows depending upon the rotor that is used: SW41 rotor - 35,000 rpm for 60 min at 20°C (accelerationl /deceleration 4)

SW40 rotor - 35,000 rpm for 60 min at 20'C (brake ofϊ)

SW28 rotor - 25,000 rpm for 60 min at 20^βC

Collect the lower opalescent band (infectious adenovirus) with 3 ml syringe and 21 needle by side puncture. Clean tube with 95% ETOH prior to collection. It is sometimes easier to remove the empty capsid band first when this band is close to the infectious virus band.

The second ultracentrifugation step is a CsCl solution (density 1.33 g/ml). In a sterile washed centrifuge tube, add 8 ml of CsCl solution (density 1.33 g ml) and overlay with the solution (band of infectious virus in 1 ml) from the previous centrifugation step. Centrifuge as above except that the duration of time will be overnight. Balance carefully by weighing tubes. Recover the opalescent adenoviral band as before. From this point forward, keep the solution at 4 ° C , Dialyze the adenoviral solution against 1 O M Tris pH

7.4, lmM MgCl^ 10% (v/v) glycerol. The solution should be autoclaved prior to use to ensure sterility. The dialysis solution should be changed 3 times during the day after which time the adenovirus solution shouldbe kept at -70"C (freeze on dry ice first). 50 μl and

100 μl aliquots are convenient for storage and subsequent use. The number of viral particles can be estimated as follows: 1 Aj₆₀ unit = 10¹² particles/ml. Generally, the ratio of particles to infectious units (pfu) is 100:1.

293 cells is a human embryonic kidney cell line which has been transformed by DNA from adenovirus type 5; they can be obtained from ATCC (ATCC #crl573). The cells are grown in D10 (DMEM 10% heat inactivated fetal calf serum, 2mM glutamine, 4.5 g/L glucose, 50 units/ml penicillin and 50 μg/ml streptomycin). 293 cells must be handled carefully as they are sensitive and quite fragile: Avoid drying - aspirate media only when ready to immediately proceed to infection. Avoid cold temperatures - always use room temperature or 37 * C media Avoid excessive mechanical manipulation - 293 cells detach easily from the dish. Hence, to avoid loosening the cell monolayer, always add media to the side of a tilted dish, Avoid prolonged time out of the incubator - cells are quite sensitive to changes inpH. Use rypsin/versene fromBiowhittaker (cat. No. 17-161E) as the cells are sensitive to the concentration of EDTA which differs from company to company. Do not allow cells to become overconfiuent as they lift easily from the plate. Do not split cells to far ( no more than 1 :4) . Avoid passaging cells too many times as they will begin to behave abnormally.

To purify adenovirus from high titre virus: Thaw virus and dilute by 4 with TE (use same batch of TE for entire procedure: lOmM Tris-HCl, lmM EDTA pH 7.4). Add SDS to final concentration of 0.5% (w/v). [0,5% x sample vol. (μl)]/20% - vol of 20% SDS to add (μl). Ad proteinase Kto 500 μg/ml final concentration [500 μg/ml x sample vol (μl)]

/ 10,000 μgml - vol of 10 mg/ml Proteinase K to add (μl). Incubate 37°C for 2 hours to overnight (O/N). Phenol extract with buffer saturated phenol (pH 8,0) to remove SDS and protein. Keep top phase (aqueous), Phenol/chloroform isoamyl alcohol (24:24:1) extract (buffer saturated, pH 8.0). Keep aqueous phase. Chlorofoπn/isoamyl alcohol

(24:1) extract. Keep aqueous phase. Ether extract ( water saturated petroleum ether).

Discard top phase (ether). Leave open tube in 37°C heating block for 30 min to allow evaporation of ether. Purify DNA by ultracentrifugation in a Centricon 30 unit Assemble unit as described in manual. Load DNA into upper chamber, fill tube to 2 ml with TE and centrifuge in fixed angle rotor at 3000 x g, RT, 30 min ( 5000 rpm in SS34 or JA20 rotors). Fill to 2 ml with TE and repeat procedure. Recover DNA by inverting upper collection chamber, inserting into collection cup and centrifugation in table top centrifuge (RT, 3000 rpm, and 2 min). Measure volume and increase to at least 100 μl with TE, Check optical Density at 260, 280 nm (2 μl) and calculate concentration. Store DNA at 4^βC.

A "nucleic acid" refers to the phosphate ester polymeric form of ribonucleosides (adenosine, guanosine, uridine or cytidine; "RNA molecules ") or deoxyribonucleosides (deoxyadenosine, deoxy guanosine, deoxythymidine, or deoxycytidine; "DNA molecules") in either single stranded form, or a double-stranded helix. Double stranded DNA-DNA, DNA-RNA and RNA-RNA helices are possible. The term nucleic acid molecule, and in particular DNA or RNA molecule, refers only to the primary and secondary structure of the molecule, and does not limit it to any particular tertiary forms, Thus, this term includes double-stranded DNA found, inter alia, in linear or circular DNA molecules (e.g., restriction fragments), plasmids, and chromosomes. In discussing the structure of particular double-stranded DNA molecules, sequences may be described herein according to the normal convention of giving only the sequence in the 5' to 3' direction along the nontxanscribed strand of DNA (i. e. , the strand having a sequence homologous to the mRNA). A "recombinant DNA" is a DNA that has undergone a molecular biological manipulation,

This invention provides for a replicable vector comprising the isolated nucleic acid molecule ofthe DNA virus. The vector includes, but is not limited to: a plasmid, cosmid, λ phage or yeast artificial chromosome (YAC) which contains at least a portion ofthe isolated nucleic acid molecule. As an example to obtain these vectors, insert and vector DNA can both be exposed to a restriction enzyme to create complementary ends on both molecules which base pair with each other and are then ligated together with DNA ligase. Alternatively, tinkers can be ligated to the insert DNA which correspond to a restriction site in the vector DNA, which is then digested with the restriction enzyme which cuts at that site. Other means are also available and known to an ordinary skilled practitioner. Regulatory elements required for expression include promoter or enhancer sequences to bind RNA polymerase and transcription initiation sequences for ribosome binding. For example, a bacterial expression vector includes a promoter such as the lac promoter and for transcription initiation the Shine-Dalgamo sequence and the start codon AUG. Similarly, a eukaryotic expression vector includes a heterologous or homologous promoter for RNA polymerase II, a downstream polyadenylation signal, the start codon AUG, and a termination codon for detachment ofthe ribosome, Such vectors may be obtained commercially or assembled from the sequences described by methods well- known in the art, for example the methods described above for constructing vectors in general. Enhancers were originally detected as genetic elements that increased transcription from a promoter located at a distant position on the same molecule of DNA. This ability to act over a large distance had little precedent in classic studies of prokatyotic transcriptional regulation. Subsequent work showed that regions of DNA with enhancer activity are organized much like promoters. That is, they are composed of many individual elements, each of which binds to one or more transcriptional proteins.

The term "vector", refers to viral expression systems, autonomous self-replicating circular DNA (plasmids), and includes both expression and nonexpression plasmids. Where a recombinant microorganism or cell culture is described as hosting an "expression vector," this includes both extrachromosomal circular DNA and DNA that has been incorporated into the host chromosome(s). Where a vector is being maintained by a host cell, the vector may either be stably replicated by the cells during mitosis as an autonomous structure, or is incorporated within the host's genome.

Expression vectors which can be used other than adenovirus include, but are not limited to, the following vectors or their derivatives : human or animal viruses such as vaccinia virus or swinepox virus, pox virus, herpes simplex virus, baculovirus, adeno-associated virus, retrovirus, cytomegalovirus, mouse mammary tumor virus (MMTV), Moloney murine leukemia virus and plasmid and cosmid DNA vectors, to name but a few. Vectors are introduced into the desired host cells by methods known in the art, e.g. , ex vivo viral vectors, particularly retroviral vectors, in vivo viral vectors, particularly defective viral vectors or adeno-associated virus vectors, transfection, electroporation, microinjection, transduction, cell fusion, DEAE dextran, calcium phosphate precipitation, lipofection (lysosome fusion), use of a gene gun, or a DNA vector transporter (see, e.g. , U.S, Patent No. 5,580,859, which is incorporated by reference and Wu et al., 1992, J. Biol. Chem. 267:963-967; Wu and Wu, 1988, J. Biol. Chem. 263:14621-14624; Hartmut et al., Canadian Patent Application No. 2,012,311, filed March 15, 1990). Such vectors include an attenuated or defective DNA virus, such as but not limited to herpes simplex virus (HSV), papillomavirus, Epstein Barr virus (EBV), adenovirus, adeno-associated virus (AAV), and the like. Defective viruses, which entirely or almost entirely lack viral genes, are preferred. Defective virus is not infective after introduction into a cell. Use of defective viral vectors allows for administration to cells in a specific, localized area, without concern that the vector can infect other cells, Thus, a solid tumor can be specifically targeted. Examples of particular vectors include, but are not limited to, a defective herpes virus 1 (HSV1) vector (Kaplitt et al., 1991, Molec, Cell. Neurosci. 2:320-330), an attenuated adenovirus vector, such as the vector described by Stratford-Perricaudet et al. (1992, J. Clin, Invest. 90:626-630), and a defective adeno-associated virus vector (Samulski et al., 1987, J. Virol. 61:3096-3101; Samulski et al., 1989, J. Virol. 63:3822-3828).

In another embodiment the gene can be introduced in a retroviral vector, e.g., as described in Anderson et al., U.S. Patent No. 5,399,346; Mann et al., 1983, Cell 33:153; Temin et al., U.S. Patent No. 4,650,764; Temin et al., U.S. Patent No. 4,980,289; Markowitz et al. , 1988, J. Virol. 62: 1120; Temin et al. , U.S. Patent No. 5,124,263; International Patent Publication No. WO 95/07358, published March 16, 1995, by Dougherty et al.; and Kuo et al., 1993, Blood 82:845. Retroviral vectors are especially attractive for transfecting solid tumors, since the cells of the tumor are replicating. Alternatively, the vector can be introduced in vitro or in vivo by lipofection. For the past decade, there has been increasing use of liposomes for encapsulation and transfection of nucleic acids in vitro. Synthetic cationic lipids designed to limit the difficulties and dangers encountered with Hposome mediated transfection can be used to prepare liposomes for in vivo transfection of a gene encoding a marker (Feigner, et. al., 1987, Proc Natl. Acad. Sci. U.S.A. 84:7413-7417; see Mackey, et al., 1988, Proc. Natl. Acad. Sci. U.S.A. 85:8027-8031)). The use of cationic lipids may promote encapsulation of negatively charged nucleic acids, and also promote fusion with negatively charged cell membranes (Feigner and Ringold, 1989, Science 337:387- 388). The use of lipofection to introduce exogenous genes into the specific organs in vivo has certain practical advantages. Molecular targeting of liposomes to specific cells, in this instance tumor cells, e.g., via tumor-specific cell surface receptors, represents one area of benefit. Lipids may be chemically coupled to other molecules for the purpose of targeting (see Mackey, et. al,, 1988, supra). Targeted peptides, e.g., hormones or neurotransmitters, and proteins such as antibodies, or non-peptide molecules could be coupled to liposomes chemically,

It is also possible to introduce the vector ex vivo or in vivo as a naked DNA plasmid. Naked DNA vectors for gene therapy can be introduced into the desired host cells by methods known in the art, e.g., transfection, electroporation, microinjection, transduction, cell fusion, DEAE dextran, calcium phosphate precipitation, use of a gene gun, or use of a DNA vector transporter (see, U.S. Patent No. 5,580,859, the contents of which are hereby incorporated by reference and e.g., Wu et al., 1992, J. Biol. Chem. 267:963-967; Wu and Wu, 1988, J. Biol. Chem, 263:14621-14624; Hartmut et al. , Canadian Patent Application No. 2,012,311, filed March 15, 1990).

The term "plasmid" refers to an autonomous circular DNA molecule capable of replication in a cell, and includes b oth the expression and nonexpression types , Where a recombinant microorganism or cell culture is described as hosting an "expression plasmid" , this includes latent viral DNA integrated into the host chromosome(s). Where a plasmid is being maintained by a host cell, the plasmid is either being stably replicated by the cells during mitosis as an autonomous structure or is incorporated within the host's genome.

"Substantial identity" or "substantial sequence identity" mean that two sequences, when optimally aligned, such as by the programs GAP or BESTFTT using default gap which share at least 65-99 percent sequence identity, share at least 75 percent sequence identity, share at least 80 percent sequence identity, share at least 90 percent sequence identity, preferably at least 95 percent sequence identity, more preferably at least 99 percent sequence identity or more. This invention contemplates a nucleic acid which has substantial sequence identity to a nucleic acid encoding β-lactamase.

The phrase "nucleic acid encoding" refers to a nucleic acid molecule which directs the expression of a specific protein or peptide. The nucleic acid sequences include both the DNA strand sequence that is transcribed into RNA and the RNA sequence that is translated into protein. The nucleic acid molecule include both the full length nucleic acid sequences as well as non-full length sequences derived from the full length protein. It being further understood that the sequence includes the degenerate codons ofthe native sequence or sequences which may be introduced to provide codon preference in a specific host cell.

Transcriptional and translational control sequences are DNA regulatory sequences, such as promoters, enhancers, polyadenylation signals, terminators, and the like, that provide for the expression of a coding sequence in a host cell

A "promoter sequence" is a DNA regulatory region capable of binding RNA polymerase in a cell and initiating transcription of a downstream (3' direction) coding sequence, For purposes of defining the present invention, the promoter sequence is bounded at its 3' terminus by the transcription initiation site and extends upstream (5' direction) to include the minimum number of bases or elements necessary to initiate transcription at levels detectable above background. Within the promoter sequence will be found atranscription initiation site (conveniently defined by mapping with nuclease SI), as well as protein binding domains (consensus sequences) responsible for the binding of RNA polymerase. Eukaryotic promoters will often, but not always, contain "TATA" boxes and "CAT" boxes. Prokaryotic promoters contain Shine-Dalgarno sequences in addition to the -10 and -35 consensus sequences.

An "expression control sequence" is a DNA sequence that controls and regulates the transcription and translation of another DNA sequence. A coding sequence is "under the control" of transcriptional and translational control sequences in a cell when RNA polymerase transcribes the coding sequence into mRNA, which is then translated into the protein encoded by the coding sequence.

The basic distinction between enhancers and promoters is operational. An enhancer region as a whole must be able to stimulate transcription at a distance; this need not be true of a promoter region or its component elements. On the other hand, a promoter must have one or more elements that direct initiation of RNA synthesis at a particular site and in a particular orientation, whereas enhancers lack these specificities. Promoters and enhancers are often overlapping and continguous , often seeming to have a very similar modular organization.

Below is a list of viral promoters , cellular enhancers and inducible enhancers that could be used in combination methods of treating a subject with cancer with the nucleic acid encoding a ^β-lactamase operatively linked to a Rous Sarcoma Virus, which include but are not limited to the following: Prostate Specific Antigen, Probasin, Prostate Specifci Membrane Antigen, Immunoglobulin Heavy Chain, Immunoglobulin Light Chain, T- Cell Receptor, HLA DQ α and Dqβ, β-Interferon, Interleukin-2, Interleukin-2 Receptor, MHC Class II 5α^κ- MHC Class II HLA-DRα, Actin, Muscle Creatine Kinase, Proalbumin(Transthyretin), Elastasel, Metallothionein, Collagenase, Albumin Gene, α-Fetoprotein, τ-Globin, c-fos, c-Ha-ras, Insulin, Neural Cell Adhesion Molecule (NCAM), α_1>lllήwqta> 2B (TH2B) Histone, Muse or Type I Collagen, Glucose- Regulated Proteins (GRP94 and GRP78), Rat Growth Hormone, Human Serum Amyloid A (SAA), Troponin I (TN I), Platelet-Derived Growth Factor, Duchenne Muscular Dystrophy, SV40, Polyoma, Retroviruses, Papilloma Virus, Hepatitis B Virs, Human Immunodeficiency Virus, Cytomegalovirus, or Gibbon Ape Leukemia Virus.

Generation and propagation of the current adenovirus vectors, which are replication deficient, depend on a unique helper cell line, designated 293, which was transformed from human embryonic kidney cells by Ad5 DNA fragments and constitutively expresses El proteins (Graham, et al., 1977). Since the E3 region is dispensible from the adenovirus genome (Jones and Shenk, 1978), the current adenovirus vectors, with the help of 293 cells, carry foreign DNA in either the El, the E3 or both regions (Grahm and Prevec. 1991). In nature, adenovirus can package approximately 105% o the wild-type genome (Ghosh-Choudhury, et al. 1987), providing capacity for about 2 extra kB of DNA. Combined with the approximately 5.5 kB, or about 15% of the total length of the vector, More than 80% of the adenovirus viral genome remains in the vectors backbone and is the source of vector-borne cytotoxicity. Also, the replication deficiency o the El deleted virus is incomplete. For example, leakage of virus gene expression has been observed with the currently available adenovirus vectors at high multiplicities of infection (Mulligan, 1993),

Helper cell lines may be derived from human cells such as human embryonic kidney cells, muscle cells, hematopoietic cells or other human embryonic mesenchymal or epithelial cells. Alternatively, the helper cells may be derived from the cells of other mammalian species that are permissive for human adenovirus. Such cells include, e. g. , Vero cells or other monkey embryonic mesenchymal or epithelial cells. As stated above, the preferred helper cell line is 293.

Other than the requirement that the adenovirus vector be replication defective, or at least conditionally defective, the nature of the adenovirus vector is not believed to be crucial to the successful practice of the invention. The adenovirus may be of any of the 42 different known serotypes or subgroups A-F, Adenovirus type 5 of subgroup C is the preferred starting material in order to obtain the conditional replication-defective adenovirus vector for use in the method of the present invention. This is because Adenovirus type 5 is a human adenovirus about which a great deal of biochemical and genetic information is know, and it has historically been used for most constructions employing adenovirus as a vector.

The phrase "therapeutically effective amount" is used herein to mean an amount equivalent to 0.001 or greater moi (1 VP - 1 virus particle).

A DNA sequence is "operatively linked" to an expression control sequence when the expression control sequence controls andregulatesthetranscriptionandtranslationofthat DNA sequence. The term "operatively linked" includes having an appropriate start signal (e.g., ATG) in front of he DNA sequence to be expressed and maintaining the correct reading frame to permit expression of the DNA sequence under the control of the expression control sequence and production ofthe desired product encoded by the DNA sequence. If a gene that one desires to insert into a recombinant DNA molecule does not contain an appropriate start signal, such a start signal can be inserted in front ofthe gene.

This invention provides a method of inducing cellular cytotoxicity of a tumor cell, comprising the steps of introducing into the tumor cell a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region ofthe genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Rous Sarcoma Virus promoter; and a prodrug having an active site which is masked by β-lactamase, whereby a functional β- lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby inducing cellular cytotoxicity of he tumor cell.

This invention provides a method of inducing cellular cytotoxicity of a tumor cell, comprising the steps of introducing into the tumor cell a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Mouse Mammary Tumor Virus promoter; and aprodrug having an active site which is masked by β-lactamase, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby inducing cellular cytotoxicity ofthe tumor cell.

As defined herein, "tumor cell" or "cancer cell" means a tissue that grows by cellular proliferation more rapidly than normal, e.g., more rapidly than adjoining cells, or other cells in the tissue. Neoplastic cells continue to grow after growth stimuli cease. Generally, tumors represent or form a distinct mass of tissue. The present invention relates to both types of tumors, but is particularly valuable in the treatment of cancers.

In one embodiment the tumor cells are selected from a group consisting of: melanoma; lymphoma; leukemia; and prostate, colorectal, pancreatic, breast, brain, or gastric carcinoma. Examples of tumors include but are not limited to: include sarcomas and carcinomas such as, but not limited to: ribrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma, lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's sarcoma, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma, adenocartinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinomas, cystadenocarcinoma, medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilms' tumor, cervical cancer, germ tumor, non-small cell lung carcinoma, small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, brain, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, hemangioblastoma, acoustic neuroma, oligodendroglioma, meningioma, melanoma, neuroblastoma, and retinoblastoma. Specifically, in an embodiment the tumor is a prostate, bladder, or brain. In a preferred embodiment the tumor is a prostate.

Prodrugs for use according to the present invention may thus be based on any compound showing a suitable chemotherapeutic effect. Such chemotherapeutic agents are preferably anti-inflammatory, anti-viral or anti-cancer compounds, and more preferably cytotoxic compounds such as nitrogen mustard agents, antifolates, nucleoside analogs, the vinca alkaloids, the anthracyclines, the mimycins, the bleomycins, the cytotoxic nucleosides, the pteridine family of drugs, the podophyophyllotoxins, the sulfonylureas (as described in EP-A-0222, 475) and low- molecular weight toxins such as the trichothecense and the colchicines, Particularly including doxorubicin, daunorubicin, aminopterin, methotrexate, taxol, methapterin, dichloromethotrexate, mitomycin C, porfirmoycin, 5-fluorouracil, 6-mercaptopurine, cytosine arabinoside, podophyllotoxin, etoposide, melphalan, vinblastine, vincristine, desacetylvinblastine hydrazide, leurosidine, vindesine, leurosine, trochothecene and desacetylcolchicine.

As defined herein "inducing chemotoxicity" means that the prodrug enzyme itself activates the prodrug into a cancer killing agent. The cell that made the prodrug enzyme and activated the prodrug into a toxic prodrug now dies, thus the combination prodrug enzyme and prodrug have induced chemotoxicity in a tumor cell that by itself would not be killed by either the prodrug enzyme or prodrug alone.

As defined herein "selectively sensitivity" means that only those cells that make the prodrug enzyme have the capabihty to activate the prodrug and are consequently sensitized to the prodrug.

As defined herein "selectively killed" means that only the cells that make the prodrug enzyme and their neighboring cells that are close enough to come into contact with the activated prodrug will be killed when the prodrug is activated and Hberated locally, Cells that do not come into contact with the activated prodrug because they are not located in the vicinity o the cell that has the gene to make the prodrug enzyme will not be killed, thus the systemic effects ofthe activated prodrug are minimized.

For example, the prodrug may comprises a cephalosporin or cephalosporin isoenzyme, mustard, or derivative thereof, congugated to a toxic agent. Other allelic variants, analogs, fragments, isoenzymes, mutants, and variants of cephalosporin are known to those skilled in the art. For example,

The "toxic agent" means any agent when introduced into a cell kills the cell or inducing the cell to die. For example, the agent may be 5-fluorouracil, methotrexate, adriamycin, or a chemotherapeutic agent.

This invention provides a method of treating a subject with cancer, comprising the steps of administering to the subject a: 1) pharmaceutical composition comprising an effective amount of a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a promoter and a suitable diluent or carrier; and 2) a pharmaceutical composition comprising an effective amount of a prodrug having an active site winch is masked by β- lactamase and a diluent or carrier, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby treating the subject with cancer. In one embodiment the promoter is a Rous Sarcoma Virus promoter. In another embodiment the promoter is aMouse Mammary Tumor Virus. In the preferred embodiment the promoter is a Rous Sarcoma Virus promoter.

As demonstrated herein, β-lactamase prodrug enzyme converts prodrug TCM into active anticancer agent which is cytotoxic to cancer cells PPC-1. PPC-1 prostate cancer cells transduced by Ad5MMTVβ-lactamase and untransduced PPC- 1 prostate cancer cells were grown in the presence of increasing doses of TCM (0-50 μM)(Fig. 9). By the TCM dose of 5 μM, the untransduced control PPC-1 growth rate was unchanged, whereas the Ad5MMTVβ-lactamase transduced PPC-1 cells were 72% of control. By 25μM TCM, control PPC-1 cells growth rates were 96% of control cells not treated with TCM. In contrast, the growth rate ofthe transduced PPC-1 cells was 21% of transduced cells not treated by TCM. At high TCM dose of 50 μM, the untransduced control cells were 51% of control not treated with TCM compared to the growth rate of transduced PPC-1 being 0,04 % of TCM untreated transduced PPC-1. Thus, PPC-1 cells transduced by Ad5MMTVβ-lactamase had a dose dependent cytotoxicity to TCM with a 99,96% reduction in growth rates compared to TCM untreated cells. These data taken together demonstrated that the genetic transfer of β-lactamase to cancer cells did render them sensitive to cephalosporin conjugated anticancer prodrugs.

The vector can be transcribed or introduced into the cell in vitro by well-known methods, e.g., by injection (see, Kubo et al., 1988), or the vectors can be introduced directly into host cells by methods well known in the art, which vary depending on the type of cellular host, including electroporation; transfection employing calcium chloride, rubidium chloride, calcium phosphate, DEAE-dextran, or other substances; microprojectile bombardment; lipofection.

In certain embodiments, gene transfer may more easily be performed under ex vivo conditions. Ex vivo gene therapy refers to the isolation of cells from an animal, the delivery of a nucleic acid into the cells, in vitro, and then the return ofthe modified cells back into an animal. This may involve the surgical removal of tissue/organs from an animal or the primary culture of cells and tissues. Anderson et al., U.S. Pat. No. 5,399,346, and incorporated herein in its entirety, disclose ex vivo therapeutic methods.

In an approach which combines biological and physical gene transfer methods, plasmid DNA of any size is combined with apolylysine-conjugated antibody specific to the adenovirus hexon protein, and the resulting complex is bound to an adenovirus vector. The trimolecular complex is then used to infect cells. The adenovirus vector permits efficient binding, internalization, and degradation ofthe endosorae before the coupled DNA is damaged. Liposome/DNA complexes have been shown to be capable of mediating direct in vivo gene transfer. While in standard liposome preparations the gene transfer process is nonspecific, localized in vivo uptake and expression have been reported in tumor deposits, for example, following direct in situ administration (Nabel, 1992). Receptor-mediated gene transfer, for example, is accomplished by the conjugation of DNA (usually in the form of covalently closed supercoiled plasmid) to a protein ligand viapolylysine. Ligands are chosen on the basis of the presence ofthe corresponding ligand receptors on the cell surface of the target cell tissue type.

Further, the vector may be administered in combination with other cytokines or growth factors include but are not limited to: IFN γ or α, IFN-β; interleukin (IL) 1, IL-2, EL- 4, IL-6, IL-7, IL-12, tumor necrosis factor (TNF) α, TNF-β, granulocyte colony stimulating factor (G-CSF), granulocyte/macrophage CSF (GM-CSF); accessory molecules, including members of the integrin superfamily and members of the Ig superfamily such as, but not limited to, LFA-1, LFA-3, CD22, and B7-1, B7-2, and ICAM-1 T cell costimulatory molecules.

Further, it is contemplated that the method of treating the subject further comprising the step of treating the subject with chemotherapy, radiation or chemopreventative therapies. It is contemplated by this invention that replacement therapy could be used similarly in conjunction with chemo- or radiotherapeutic intervention. To inhibit cell growth, for exampler to kill prostate cells, such as malignant or metastatic cells, using the methods and compositions ofthe present invention, one would contact a "target" cell with the expression vector and at least one DNA damaging agent. In one embodiment the cell is contacted with a single composition or pharmacological formulation that includes both agents, or by contacting the cell with two distinct compositions or formulations, at the same time, wherein one composition includes the vector and the other includes the DNA damaging agent, In another embodiment, treatment with the vector may precede or follow the DNA damaging agent treatment by intervals ranging from minutes to weeks. Protocols and methods are known to those skilled in the art.

DNA damaging agents or factors are known to those skilled in the art and means any chemical compound or treatment method that induces DNA damage when applied to a cell Such agents and factors include radiation and waves that induce DNA damage such as, gamma -irradiation, X-rays, UV-irradiation, microwaves, electronic emissions, and the Uke. A variety of chemical compounds, also described as "chemotherapeutic agents", function to induce DNA damage, all of which are intended to be of use in the combined treatment methods disclosed herein. Chemotherapeutic agents contemplated to be of use, include, e,g„ adriamycin, 5-fluorouracil (5FU), etoposide (VP-16), camptothecin, actinomycin-D, mitomycin C, cisplatin (CDDP) and even hydrogen peroxide. The invention also encompasses the use of a combination of one or more DNA damaging agents, whether radiation-based or actual compounds, such as the use of X-rays with cisplatin or the use of cisplatin with etoposide,

Other neoplastic or toxic agents include but are not limited: 5-fluorouracil , methotrexate and adriamycin which may be linked in each case to, for example, a cephalosporin (see WO-A94 01 137 and EP-A-0 382 411) or cephalosporin mustards (see EP-A-O 484 870). In each case the cephalosporin/toxic agent conjugate shows markedly reduced toxiciry but can be converted to the active form by β-lactamase thus making it suitable for use as a prodrug in GDEPT. Other toxic agents can be linked to cephalosporins in a similar way.

In another embodiment one may irradiate the localized tumor site with DNA damaging radiation such as X-rays, UV-light, gamma -rays or even microwaves. Alternatively, the tumor cells may be contacted with the DNA damaging agent by administering to the subj ect a therapeutically effective amount of a pharmaceutical composition comprising a DNA damaging compound such as, adriamycin, 5-fluorouracil, etoposide, camptotliecin, actinomycin-D, mitomycin C, or more preferably, cisplatin. The DNA damaging agent may be prepared and used as a combined therapeutic composition, or kit, by combining it with a ^β-lactamase expression construct, as described above. Agents that directly cross-link nucleic acids, specifically DNA, are envisaged and are shown herein, to eventuate DNA damage leading to a synergistic antineoplastic combination. Agents such as cisplatin, and other DNA alkylating may be used. Cisplatin has been widely used to treat cancer, with efficacious doses used in clinical applications of 20 mg m² for 5 days every three weeks for a total of three courses. Cisplatin is not absorbed orally and must therefore be delivered via injection intravenously, subcutaneously, intratumorally or intraperitoneally. Agents that damage DNA also include compounds that interfere with DNA replication, mitosis and chromosomal segregation, Such chemotherapeutic compounds include adriamycin, also known as doxorubicin, etoposide, verapamil, podophyllotoxin, and the like. Widely used in a clinical setting for the treatment of neoplasms, these compounds are administered through bolus injections intravenously at doses ranging from 25-75 mg/m² at 21 day intervals for adriamycin, to 35-50 mg/m² for etoposide intravenously or double the intravenous dose orally. In one embodiment the prodrug is cyclophosphamide, isoenzymes, analogs and derivatives thereof. In another embodiment the prodrug is ifosfamide, isoenzymes, variants, analogs and derivatives thereof.

Agents that disrupt the synthesis and fidelity of nucleic acid precursors and subunits also lead to DNA damage, As such a number of nucleic acid precursors have been developed. Particularly useful are agents that have undergone extensive testing and are readily available. As such, agents such as 5-fluorouracil (5-FU), are preferentially used by neoplastic tissue, making this agent particularly useful for targeting to neoplastic cells. Although quite toxic, 5-FU, is applicable in a wide range of carriers, including topical, however intravenous adnajnistration with doses ranging from 3 to 15 mg/kg/day being commonly used.

Other factors that cause DNA damage and have been used extensively include what are commonly known as gamma -rays, X-rays, and or the directed delivery of radioisotopes to tumor cells. Other forms of DNA damaging factors are also contemplated such as microwaves and UV-irradiation, It is most likely that all of these factors effect a broad range of damage DNA, on the precursors of DNA, the replication and repair of DNA, and the assembly and maintenance of chromosomes. Dosage ranges for X-rays range from daily doses of 50 to 200 roentgens for prolonged periods of time (3 to 4 weeks), to single doses of 2000 to 6000 roentgens, Dosage ranges for radioisotopes vary widely, and depend on the half-life of he isotope, the strength and type of radiation emitted, and the uptake by the neoplastic cells.

This invention pro ides a pharmaceutical composition comprising the rephcation-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in the El and E3 region ofthe genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Rous Sarcoma Virus promoter and a suitable diluent or carrier.

This inventionprovides a pharmaceutical composition comprising the rephcation-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in the El and E3 region of he genome and an insertion within the region of a nucleic acid encoding an β-lactamase under the control of a Mouse Mammary Tumor Virus promoter and a suitable diluent or carrier.

As used herein, "pharmaceutical composition" could mean therapeutically effective amounts of polypeptide products of the invention together with suitable diluents, preservatives, solubilizers, emulsifiers, adjuvant and/or carriers. A "therapeutically effective amount" as used herein refers to that amount which provides a therapeutic effect for a given condition and administration regimen. Such compositions are liquids or lyophilized or otherwise dried formulations and include diluents of various buffer content (e.g., Tris-HCl., acetate, phosphate), pH and ionic strength, additives such as albumin or gelatin to prevent absorption to surfaces, detergents (e.g., Tween 20, Tween 80, Pluronic F68, bile acid salts), solubilizing agents (e.g., glycerol, polyethylene glycerol), anti- oxidants (e.g., ascorbic acid, sodium metabisulfite), preservatives (e.g., Thimerosal, benzyl alcohol, parabens), bulking substances or tonicity modifiers (e.g., lactose, mannitol), covalent attachment of polymers such as polyethylene glycol to the protein, complexation with metal ions, or incorporation ofthe material into or onto particulate preparations of polymeric compounds such as polylactic acid, polglycolic acid, hydrogels, etc, or onto liposomes, microemulsions, micelles, unilamellar or multilamellar vesicles, erythrocyte ghosts,- or spheroplasts. Other embodiments of the compositions of the invention incorporate particulate forms protective coatings, protease inhibitors or permeation enhancers for various routes of administration, including parenteral, pulmonary, nasal and oral. In one embodiment the pharmaceutical composition is administered parenterally, intratumorally, paracancerally, transmucosally, transdermally, intramuscularly, intravenously, intradermally, subcutaneously, intraperitonealy, intraventricularly, intracranially.

Further, as used herein "pharmaceutically acceptable carrier" are well known to those skilled in the art and include, but are not limited to, 0.01-O.lM and preferably 0.05M phosphate buffer or 0.8% saline. Additionally, such pharmaceutically acceptable carriers maybe aqueous or non-aqueous solutions, suspensions, and emulsions. Examples of non- aqueous solvents are propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable organic esters such as ethyl oleate, Aqueous carriers include water, alcoholic/aqueous solutions, emulsions or suspensions, including saline and buffered media, Parenteral vehicles include sodium chloride solution, Ringer's dextrose, dextrose and sodium chloride, lactated Ringer's or fixed oils. Intravenous vehicles include fluid and nutrient replenishers, electrolyte replenishers such as those based on Ringer's dextrose, and the like. Preservatives and other additives may also be present, such as, for example, antimicrobials, antioxidants, collating agents, inert gases and the like.

The term "adjuvant" refers to a compound or mixture that enhances the immune response to an antigen. An adjuvant can serve as a tissue depot that slowly releases the antigen and also as a lymphoid system activator that non-specifically enhances the immune response (Hood et al., Immunology, Second Ed., 1984, Benjamin/Cummings: Menlo Park, California, p. 384). Often, a primary challenge with an antigen alone, in the absence of an adjuvant, will fail to elicit a humoral or cellular immune response. Adjuvant include, but are not limited to, complete Freund's adjuvant, incomplete Freund's adjuvant, saponin, mineral gels such as aluminum hydroxide, surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil or hydrocarbon emulsions, keyhole limpet hemocyanins, dinitrophenol. Preferably, the adjuvant is pharmaceutically acceptable.

Controlled or sustainedrelease compositions include formulation in Upophilic depots (e.g. fatty acids, waxes, oils). Also comprehended by the invention are particulate compositions coated with polymers (e.g. poloxamers or poloxamines) and the compound coupled to antibodies directed against tissue-specific receptors, ligands or antigens or coupled to ligands of tissue-specific receptors. Other embodiments of the compositions ofthe invention incorporate particulate forms protective coatings, protease inhibitors or permeation enhancers for various routes of administration, including parenteral, pulmonary, nasal and oral.

When administered, compounds are often cleared rapidly from mucosal surfaces or the circulation and may therefore elicit relatively short-lived pharmacological activity. Consequently, frequent administrations of relatively large doses of bioactive compounds may by required to sustain therapeutic efficacy. Compounds modified by the covalent attachment of water-soluble polymers such as polyethylene glycol, copolymers of polyethylene glycol and polypropylene glycol, carboxymethyl cellulose, dexrran,ρolyvinyl alcohol, polyvinylpyrrolidone orpolyproline are known to exhibit substantially longer half-lives in blood following intravenous injection than do the corresponding unmodified compounds (Abuchowski et al,, 1981; Newmark et al., 1982; and Katre et al., 1987). Such modifications may also increase the compound's solubility in aqueous solution, eliminate aggregation, enhance the physical and chemical stability ofthe compound, and greatly reduce the immunogenicity and reactivity of the compound. As a result, the desired in vivo biological activity may be achieved by the administration of such polymer- compound abducts less frequently or in lower doses than with the unmodified compound.

Dosages. The sufficient amount may include but is not limited to from about 1 μg/kg to about 1000 mg/kg. The amount may be 10 mg/kg. The pharmaceutically acceptable form ofthe composition includes a pharmaceutically acceptable carrier.

The preparation of therapeutic compositions which contain an active component is well understood in the art. Typically, such compositions are prepared as an aerosol ofthe polypeptide delivered to the nasopharynx or as injectables, either as liquid solutions or suspensions, however, solid forms suitable for solution in, or suspension in, liquid prior to injection can also be prepared. The preparation can also be emulsified. The active therapeutic ingredient is often mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipients are, for example, water, saline, dextrose, glycerol, ethanol, or the like and combinations thereof. In addition, if desired, the composition can contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents which enhance the effectiveness ofthe active ingredient.

An active component can be formulated into the therapeutic composition as neutralized pharmaceutically acceptable salt forms. Pharmaceutically acceptable salts include the acid addition salts (formed with the free amino groups of the polypeptide or antibody molecule) and which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed from the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethylamine, 2-etbylamino ethanol, histidine, procaine, and the like,

A composition comprising "A" (where "A" is a single protein, DNA molecule, vector, etc.) is substantially free of "B" (where "B" comprises one or more contaminating proteins, DNA molecules, vectors, etc.) when at least about 75% by weight of the proteins, DNA, vectors (depending on the category of species to which A and B belong) in the composition is "A" . Preferably, "A" comprises at least about 90% by weight ofthe A+B species in the composition, most preferably at least about 99% by weight.

The term "unit dose" when used in reference to a therapeutic composition ofthe present invention refers to physically discrete units suitable as unitary dosage for humans, each unit containing a predetermined quantity of active material calculated to produce the desired therapeutic effect in association with the required diluent; i. e. , carrier, or vehicle.

Several non-viral methods for the transfer of expression constructs into cultured mammalian cells also are contemplated by the present invention. These include calcium phosphateprecipitation(GrahamandVanDerEb, 1973; Chen and Okayama, 1987;Rippe et al., 1990) DEAJE-dextran (Gopal, 1985), electroporation (Tur-Kaspa et al., 1986; Potter et al., 1984), direct microinjection (Harland and Weintraub, 1985), DNA-loaded liposomes (Nicolau and Sene, 1982; Fraley et al., 1979) and lipofectamine-DNA complexes, cell sonication (Fechheimer et al., 1987), gene bombardment using high velocity microprojectiles (Yang etal., 1990), and receptor-mediated transfection (Wuand Wu, 1987; Wu and Wu, 1988). Some of these techniques maybe successfully adapted for in vivo or ex vivo use. Also, helper cell lines may be derived from human cells such as human embryonic kidney cells, muscle cells, hcmatopoietic cells or other human embryonic mesenchymal or epithelial cells. Alternatively, the helper cells may be derived from the cells of other mammalian species that are permissive for human adenovirus. Such cells include, e.g, , Vero cells or other monkey embryonic mesenchymal or epithelial cells. As stated above, the preferred helper cell line is 293.

In another embodiment, the active compound can be delivered in a vesicle, in particular a liposome (see Langer, Science 249:1527-1533 (1990); Treat etal., in Liposomes in the Therapy of Infectious Disease and Cancer, Lopez-Berestein and Fidler (eds,), Liss, New York, pp. 353-365 (1989); Lopez-Berestein, ibid., pp. 317-327; see generally ibid).

In yet another embodiment, the therapeutic compound can be delivered in a controlled release system. For example, the polypeptide may be administered using intravenous infusion, an implantable osmotic pump, a transdermal patch, liposomes, or other modes of administration. In one embodiment, a pump may be used (see Langer, supra; Sefton, CRC Crit. Ref. Biomed. Eng. 14:201 (1987); Buchwald et al., Surgery 88:507 (1980); Saudek et al.₃ N. Engl. J. Med. 321:574 (1989)). In another embodiment, polymeric materials can be used (see Medical Applications of Controlled Release, Langer and Wise (eds.), CRC Pres., Boca Raton, Florida (1974); Controlled Drug Bioavailability, Drug Product Design and Performance, Smolen and Ball (eds.), Wiley, New York (1984); Ranger and Peppas, J. Macromol. Sci. Rev. Macromol. Chem. 23:61 (1983); see also Levy et al., Science 228:190 (1985); During etal., Ann. Neural.25:351 (1989); Howard et al., J. Neurosurg. 71:105 (1989)). In yet another embodiment, a controlled release system can be placed in proximity ofthe tiierapeutic target, i.e., the brain, thus requiring only a fraction of the systemic dose (see, e.g., Goodson, in Medical Applications of Controlled Release, supra, vol. 2, pp. 115-138 (1984)). Preferably, a controlled release device is introduced into a subject in proximity of the site of inappropriate immune activation or a tumor. Other controlled release systems are discussed in the review by Langer (Science 249:1527-1533 (1990)).

As can be readily appreciated by one of ordinary skill in the art, the methods and pharmaceutical compositions of the present invention are particularly suited to administration to a mammal, preferable a human subject.

In the therapeutic methods and compositions of the invention, a therapeutically effective dosage of he active component is provided. A therapeutically effective dosage can be determined by the ordinary skilled medical worker based on patient characteristics (age, weight, sex, condition, complications, other diseases, etc), as is well known in the art. Furthermore, as further routine studies are conducted, more specific information will emerge regarding appropriate dosage levels for treatment of various conditions in various patients, and the ordinary skilled worker, considering the therapeutic context, age and general health of the recipient, is able to ascertain proper dosing. Generally, for intravenous injection or nifusion, dosage may be lower than for intraperitoneal, intramuscular, or other route of administration, The dosing schedule may vary, depending on the circulation half-life, and the formulation used. The compositions are administered in a manner compatible with the dosage formulation in the therapeutically effective amount. Precise amounts of active ingtedient required to be administered depend on the judgment of the practitioner and are peculiar to each individual. However, suitable dosages may range from about 0.1 to 20, preferably about 0.5 to about 10, and more preferably one to several, milligrams of active ingredient per kilogram body weight of individual per day and depend on the route of administration. Suitable regimes for initial administration and booster shots are also variable, but are typified by an initial administration followed by repeated doses at one or more hour intervals by a subsequent injection or other administration. Alternatively, continuous intravenous infusion sufficient to maintain concentrations of ten nanomolar to ten micromolar in the blood are contemplated. The present invention pro videsakitcomprisingthe all the essential materials and reagents required for inhibiting prostate tumor cell proliferation, fransforming prostate cells or detecting prostate cancer cells, may be assembled together in a kit. This generally will comprise selected expression constructs. Also included may be various media for replication ofthe expression constructs and host cells for such replication. Such kits will comprise distinct containers for each individual reagent. When the components ofthe kit are provided in one or more liquid solutions, the liquid solution preferably is an aqueous solution, with a sterile aqueous solution being particularly preferred. For in vivo use, the expression construct may be formulated into a pharmaceutically acceptable syringeable composition. In this case, the container means may itself be an inhalent, syringe, pipette, eye dropper, or other such like apparatus, from which the formulation may be applied to an infected area ofthe body, such as the lungs, injected into an animal, or even applied to and mixed with the other components of the kit. The components of the kit may also be provided in dried or lyophilized forms. When reagents or components are provided as a dried form, reconstitution generally is by the addition of a suitable solvent. It is envisioned that the solvent also may be provided in another container means,

The kits ofthe present invention also will typically include a means for containing the vials in close confinement for commercial sale such as, e.g., injection or blow-molded plastic containers into which the desired vials are retained. Irrespective ofthe number or type of containers, the kits of the invention also may comprise, or be packaged with, an instrument for assisting with the injection/administration or placement ofthe ultimate complex composition within the body of an animal. Such an instrument may be an inhalent, syringe, pipette, forceps, measured spoon, eye dropper or any such medically approved delivery vehicle,

The following examples are presented in order to more fully illustrate the preferred embodiments o the invention. They should in no way be construed, however, as limiting the broad scope ofthe invention, EXPERIMENTAL DETAILS SECTION

MATERIALS AND METHODS Cell culture and medium: Human embryonic kidney 293 cells were obtained from ATCC (Rockville, MD) and were grown in Dulbecco's modified Eagle medium (D-MEM) (Gibco BRL, Gaithersburg, MD) with 10% heat inactivated fetal bovine serum (FBS) (Hyclone Laboratories Logan, UT). Human prostate cancer cell lines PPC-1 and PC3 were grown in RPMI 1640 medium (Cellgro Hemdon, VA) with 10% FBS. All cells were grown inraedium containing 100 units/ml penicillin and 100 μg/ml streptomycin at 37°C in 5% CO₂,

Construction and purification of adenoviruses expressing β-lactamase: β-lactamase gene (ampicillin resistant gene) was released from plasmid pR14.BA, a derivative of pBR322 by Bsp HI digestion. The 966 bp ^β-lactamase cDNA was used to replace lacZ gene in adenoviral shuttle vector pAdSMMTVlacZ (Steiner et al 1998) to form ρAd5MMTVβ-lactamase, Recombinant adenovirus Ad5MMTVβ-lactamase was generated via in vitro recombination in 293 cells by cotransfection of pJM17, an adenoviral genome plasmid, by calcium phosphate method (Kingston, R.E. (1993), Introduction of DNA into mammalian cell. In: Current Protocols in Molecular Biology F.M. Ausubel FM et al ., eds. (John Wiley & Sons, Inc., New York) pp. 9.1.4- .1.9), and cells were maintained in plaque overlay mixture (Graham et al 1991). Plaques usually appeared in 10 to 12 days. Individual plaques were screened by PCR using one primer specific for MMTV LTR (5'GCGGAACGGACTCACCATAG3') and the other primer specific for ^β-lactamase gene (5'CTCATGGTTATGGCAGCACTGC3'). PCR was performed in a 50-μl volume containing DNA from one plaque, 2 mM M Cla, 50 mM KC1, 0.2 mM each of dNTPs, 20 mM Tris-HCl (pH 8.4), 1 μM each ofthe primers, and 2.5 units of DNA Taq polymerase (Gibco BRL, Gaithersburg, MD). The reaction was carried out at 95°C for 5 min; 30 cycles at 95°C for 1 min; 58°C for 1 min; and 72°C for 1 min. This was followed by an extension period of 72°C for 10 min. Ad5RS Vβ-lactamase, in which β-lactamase gene was under the control of Rous Sarcoma virus (RSV) promoter, was generated as described above. The primer specific for RSV promoter was 5' CGGGTCTGACATGGATTGGACG3', and the primer specific for β- lactamase was 5'CTCATGGTTATGGCAGCACTGC3\

Adenoviral preparation: Individual clones of each adenovirus was obtained by twice plaque purification. Single viral clones were propagated in 293 cells. The culture medium ofthe 293 cells showing the completed cytopathic effect was collected, The adenovirus was purified and concentrated by twice CsCl2 gradient ultracentrifugation. The viral titers were determined by plaque assays in 293 cells ( Graham, F,L. and Prevec, L, (1991). Manipulation of adenovirus vectors. In: Methods in Molecular Biology. Vol 7; Gene transfer and expression protocols. E.J. Murray, ed, Clifton: (The Human Press Inc., Clifton, New Jersey, at pp. 109-128. ),

Adenoviral transduction in vitro: Adenoviral infection ofthe cell lines was carried out by adding the viral solution to cell monolayers followed by incubating the cell viral mixture at 37°C for 90 min with brief agitation every 15 min. After 3 h exposure, the viral solution was removed and fresh medium was added to the cell culture. For cells infected by Ad5MMTVlacZ, 1 μM dexamethasone (Dex) (Sigma, St. Louis, MO) was added to the medium and the cells were then incubated at 37°C for 72 h.

X-gal staining: Adenoviruses expressing reporter gene β-galactosidase (Ad5RSVlacZ and AdSMMTVlacZ) were used to determine the adenoviral transduction and expression efficiency under the control of RSV and MMTV promoters in human prostate cancer cells. The same transduction method was used as described above. Cultured cells expressing lacZ gene were fixed for 5 rain at 4°C in 2% (v/v) formaldehyde and 0.2% (v/v) glutaraldehyde in PBS and rinsed three times with PBS. The staining reaction was performed on cells by incubating overnight at 37°C in lmg/ l X-gal (5-bromo-4-chloro-

3-indolyl-β-D-galactopyranoside) (Gibco BRL, Gaithersburg, MD), 5 mM potassium ferricyanide, 5 mM potassium ferrocyanide, and 2 mM MgCl₂ in PBS. β-galactosidase assay: Cells were harvested and iysed by three cycles of freezing and thawing in 0.25 M Tris-HCl, pH 8.0. After centrifugation at 12,000 rpm in a microcentrifuge for 10 min at 4°C, the supernatant was collected. The protein concentration was determined by Coomassie Plus Protein Assay Reagent (Pierce, Rockford, IL). The colorimetric β-galactosidase assay was performed by using β-gal Assay Kit (Invitrogen, Carlsbad, CA) according to manufacturer's protocol.

Reverse-transcriptase polymerase chain reaction RT-PCR); PC3 cells were transduced by Ad5MMTVβ~lactamase at moi of200 in medium containing 1 μMDex for 72 h. Total RNA was isolated from control PC3 cells and adenoviral transduced PC3 cells using RNeasy Total RNA Kit (Qiagen, Clarita, CA) according to the Manufacturer's protocol. Reverse transcriptase reaction was carried out using Superscript II RT (Gibco BRL) and 1 μg total RNA. An aliquot ofthe RT mixture was subsequently used for the PCR reaction. The primers were specific for β-lactamase coding sequence and resulted in a 365 bp PCR amplification fragment. Primer 1 was 5 ' C C G T G T C G C C C T T A T T C C C 3 ' an d P r i m e r 2 w a s 5'CTCATGGTTATGGCAGCACTGC3'. PCR was performed in 50-μl total volume containing 10 μl above RT mixture, in a final concentration of 4 mM MgCl₂, 50 mM KC1, 0.2 mM each of dNTPs, 20 mM Tris-HCl (pH 8.4), 2 μM each ofthe primers, and 2.5 units of Taq DNA polymerase (Gibco BRL). The reaction was carried out at 94°C for 4 min; then for 30 cycles at 94°C for 1 min, 58°C for 1 min, and 72°C for 1 min; followed by at 72°C for 10 min.

β-lactamase activity assay: PPC-1 cells were transduced by Ad5MMTVβ-lactamase at moi=l,000 and incubated in medium containing 1 μM Dex for 72 h. The cells were harvested by 0.5% trypsin and centrifuged at 1,000 rpm for 5 min. After washing once with PBS, the cell pellet was collected at 1,000 ipm at 5 min. The cells were incubated with 1 x Lysis buffer (Promega, Madison, WI) on ice for 1 h with brief vortex every 10 min. The cell lysates were centrifuged at 10,000 rpm for 2 min, and the supernatant was collected to perform the enzyme assay. Standard β-lactamase substrates cephalothin and cephaloridine (both from Sigma) and prodrug 7-(2-thiophenylacetamido) cephalosporin mustard (TCM) were used in enzyme assay. The cell supernatants (50 μl) were incubated at 37°C with 1 ml of 100 μM cephalothin, 100 μM cephaloridine, and 50 or 70 μM TCM respectively, The absorbance was detected by a spectrophotometry at different incubation time points, and the initial rate ofthe enzyme reaction was calculated and transformed as the β-lactamase enzyme activity.

Cytotoxicity assay: PPC- 1 cells were plated in 96-well microtiter plates at a density of 2,000 cells/well and incubated at 37°C. The cells were untreated or transduced with control virus Ad5RSVlacZ (moi=200), or Ad5MMTVβ-lactamase (moi=200) . Control PPC-1 and transduced PPC-1 cells were grown in medium containing 1 μM Dex for 72 h. Cells were treated with increasing concentrations of TCM (0-70 μM) for 2 days at 37°C. ³H-thymidine (1 μCi/well) (ICN) was added to the cells for the final 18 h of incubation. Cells were then harvested onto filter paper using a 12- well harvester (Brandel M-12, Biomedical Research and Development Laboratories Inc, Gaithersburg, MD). Filter discs were removed from the cells harvester and placed in glass vials containing 5 ml of EcoLite Plus™ scintillation cocktail (ICN Biomedical, Costa Mesa, CA). Radioactivity was counted in a liquid scintillation counter (Model L56800, Beckman Instruments Inc., Fullerton, CA).

RESULTS Construction and sequence of Ad5RSVβ-lactamase and Ad5MMTv'β-lactamase: The construction of the replication adenoviral El and E3 deleted vectors containing the wildtype β-lactamase gene is described in the METHODS section. Figures 1 and 2 summarize the essential features ofthe Ad5RS Vβ-lactamase and Ad5MMTVβ-lactamase, respectively. The DNA sequences are shown in Figure 10 for Ad5RSVβ-lactamase and Figure 11 for Ad5MMTVβ-lactamase.

Cancer cells are efficiently transduced by adenoviral vectors: RepUcatioiwleficient adenoviruses containing lacZ under the control of RSV and breast and prostate-specific promoter MMTV were generated- The promoter activity and specificity among the MMTV and RSV promoters were compared in prostate, non-prostate, and breast cancer cells both in vitro and in vivo. Promoter activity in vitro: To compare the promoter activity in vitro, human prostate cancer PPC-1 cells were transduced by these Ad-lacZ at different moi. The in situ lacZ expression was determined by X-gal staining. To maximize the promoter activity in vitro, Dex was added to the cells transduced by Ad5MMTVlacZ because MMTV LTR contains glucocorticoid responsive element (GRE). The number of blue cells was evaluated to assess promoter activity. As shown in Fig. 3, both Ad-lacZ vectors expressed β-Gal. However, Ad5MMTVlacZ required a 10-fold high moi than Ad5RSVIacZ to achieve the same percent of blue cells moi=1000 for AdSMMTVlacZ compared to moi=100 by Ad5RSVlacZ (Fig.4). The percent of blue cells were proportional to the increase of moi, and the RSV promoter was consistently 10-fold stronger than the MMTV promoter.

Cell extracts from adenoviral transduced cells were analyzed for the β-galactosidase enzymatic activity. While the results were consistent with the blue cells counts, there was a greater difference between RSV and MMTV promoter activity determined by β- galactosidase assay. AdSRSVlacZ at moi= 100 had β-gal activity that was 10-foldhigher than that achieved by Ad5MMTVlacZ at moi=l,000 (Fig. 5 and Fig. 6).

Promoter specificity in vitro : The specificity ofthe adenoviral vectors containing the RSV and MMTV was studied in vitro in various cell lines. Prostate and non-prostate cells were transduced with either Ad5MMTVLacZ or Ad5RSVLacZ. β-Gal expression was determined by X-gal staining. To differentiate the potential involvement of endogenous hormone and glucocorticoid to the activation of promoter, the cells transduced by Ad5MMTVlacZ were treated with or without with Dex. As shown in Table 1 , in general, MMTV prostate-specific promoters effectively expressed lacZ transgene in all the prostate-derived cells, but not in non-prostate cells. MMTV promoter (AdSMMTVlacZ) activated lacZ expression in all the cells in the presence of its inducer Dex (Table 1), which was not surprising because MMTV promoter is used as an inducible promoter in general. In the absence of Dex, MMTV promoter only activated lacZ expression in three out of seven prostate cell lines, and the presence of Dex increased the lacZ expression dramatically. In addition, MMTV promoter was active in MCF-7 breast cancer cells even in the absence of Dex. These results indicated that MMTV promoter can be selectively activated in both prostate and breast cells and its activity is inducible by Dex.

Adenoviral transduction efficiency in vivo: To compare the promoter activity and distribution of transgene expression in vivo, human prostate xenograft tumors transduced by various Ad-lacZ were stained by X-gal. Figure 7 shows the X-gal staining pattern of the wholemount of tumors transduced by Ad5RSVlacZ at a dose of 1X10^P pfu (Figure 7A) and 1X10¹⁰ pfu (Figure 7B). A single injection of adenoviral vector into 50mm³ tumors resulted in a surprisingly wide distribution of viral infections.

Cancer cell transduced by Adβ-lactamase produce β-lactamase mRNA: PC3 human prostate cancer cell line was either untreated or transduced with Ad5MMTVβ-lactamase at a moi= 200. The PC3 cells were incubated in RPMI 1640 medium containing lμM dexamethasone for 72 hours. At 72 hours, RNA was extracted and subjected to RT-PCR for β-lactamase (365bp) (Fig. 8, lanes 2-4) and RNA control primers β2 microglobuhn exon2-exon4 (536 bp)(Fig. 8, lanes 5-6). RT-PCR amplification products were then subjected to gel electrophoresis. The β-lactamase 365 bp PCR product was detected for the control β-lactamase plasmid and the PC3 cells transduced by Ad5MMTVβ-lactamase, but not in the control untreated PC3 cells. Control RNA RT-PCR confirmed that the RNA was not degraded as both the untreated and transduced PC3 cell had the expected 536 bp product. Thus, human prostate cancer cells PC3 transduced by Ad5MMTVβ-lactamase expressed β-lactamase mRNA.

Cancer cells transduced by Adβ-lactamase express functional β-lactamase: To determine whether or not the prostate cancer cells transduced by Ad5MMTVβ-lactamase produced a functional β-lactamase prodrug enzyme, Ad5MMTVβ-lactamase treated (moi=l 000) and untreated PPC- 1 prostate cancer cells were incubated for 3 days in RPMI 1640 medium containing lμM Dex, Cephaloridine, cephalothin, and prodrug TCM (prodrug composed of cephalosporin conjugated to nitrogen mustard) was added to the medium and the velocity of substrate degradation (μM/min) was determined. As summarized in Table 2, the adenoviral vector mediated β-lactamase was active against all three substrates, whereas the control untreated cells had no activity. Moreover, consistent with the observation that the RSV promoter is more active than the MMTV promoter, PPC-1 cells transduced by Ad5RSVβ-lactamase had an even higher degradation ofthe tested substrates (data to be submitted at a later date). Thus, the β-lactamase produced by the PPC-1 prostate cancer cells was present and functional, Moreover, those cancer cells transduced by Ad5RSVβ-lactamase had greater β-lactamase than the cancer cells that were transduced by Ad5MMTVβ-lactamase presumably because RSV driven construct produced more β-lactamase protein,

β-lactamase prodrug enzyme converts prodrug TCM into active anticancer agent which is cytotoxic to cancer cells PPC-1: PPC-1 prostate cancer cells transduced by Ad5MMTVβ-lactamase and untransduced PPC-1 prostate cancer cells were grown in the presence of increasing doses of TCM (0-50 μM)(Fig.9). By the TCM dose of 5 μM, the untransduced control PPC-1 growth rate was unchanged, whereas the Ad5MMTVβ- lactamase transduced PPC-1 cells were 72% of control. By 25μM TCM, control PPC-1 cells growth rates were 96% of control cells not treated with TCM. In contrast, the growth rate ofthe transduced PPC-1 cells was 21% of transduced cells not treated by TCM. At high TCM dose of 50 μM, the untransduced control cells were 51% of control not treated with TCM compared to the growth rate of transduced PPC-1 being 0.04 % of TCM untreated transduced PPC-1. Thus, PPC- 1 cells transduced by Ad5MMTVβ- lactamase had a dose dependent cytotoxicity to TCM with a 99.96% reduction in growth rates compared to TCM untreated cells. These data taken together demonstrated that the genetic transfer of β-lactamase to cancer cells did render them sensitive to cephalosporin conjugated anticancer prodrugs.

Table 1. LacZ expression driven by prostate-specific promoters in prostate and non-prostate cells

Ad5MMTVlacZ

Cell line withi with

TSU - +

LNCaP - +

PPC-1 +

P PCC--33 + +

DU145 +

MatLyLu -

G -

MCF-7 (mammary) +

33TT33 ( (fifibbrroobbllaasstt)) -- +

RT4 (bladder) +/- +/-

Culture cells (seven prostate cancer cell lines and three non-prostate cells) were infected by adenoviruses (moi = 200) for 3 h then incubated in charcoal/resin-stripped-serum medium *with or *without inducers (50 tiM dihydrotestosterone for AdPBlacZ- and AdPSAlacZ-transduced cells, and 1 μMdexamethasonefor Ad5MMTVlacZ-transduced cells) for 50 h at 37°C. The cells were then processed to X-gal staining for detection of lacZ expression.

+ indicates the presence of blue cells after X-gal staining ++ indicates more blue cells indicates absence of blue cells +/- indicates that only very few blue cells (<0-l%) were observed. Table 2. β-lactamase activity assay

Substrate Detection Initial Velocity

Cone. (μM) WV (nm) (μM/min)

PPC-1 PPC-1/Adβ-lact

Cephaloridine 100 260 4.11 47.24

C halothin 100 260 6.0

TCM 50 265 1.41

TCM 75 265 2.24

PPC-1 cells were transduced by Ad5MMTVβ-lactamase (Adβ-lact) at moi=l,000 and incubated at 37°C in medium containing 1 μM Dex. The detail for enzymatic assay was described in die MATERIALS AND METHODS.

DISCUSSION

The adenovirus vector as demonstrated is ideally suited for β-lactamase gene therapy. The adenovirus efficiently infects mammalian cells and is not dependent on whether cells are dividing (Roth et al. 1997). In the present results, it is shown that the adenoviral vector has high transduction rate and high expression ofthe transgene. In addition, the adenovirus directs transient expression ofthe transgene which is a safety feature if the adenovirus infects normal cells. Although any mammalian promoter may be combined with β-lactamase in the adenoviral construct, it is clear that some promoter may be more active than others in stimulating expression ofthe transgene. In this current study the RSV has greater activity than the MMTV promoter, but the MMTV has better tissue selectivity. Thus, the trade-off for tissue specificity is loss of activity. This problem may be theoretically circumvented in the case of the MMTV promoter as the addition or treatment with exogenous glucocorticoids should stimulate the MMTV promoter (Mulleret /. 1990).

In summary, this application employed a replication deficient El and E3 deleted type adenoviral vector contaύiing amammalian expression promoter (for example, MMTV and RSV) to deliver and express in cancer cells wild type β-lactamase type 1 as a prodrug enzyme for human gene therapy. Moreover, the feasibility of this approach has been demonstrated: adenoviral vectors efficiently transduce cancer cells, adenoviral vectors containing β-lactamase type 1 transfer this gene to cancer cells, cancer cells express functional β-lactamase type 1, and the expression of β-lactamase by cancer cells in combination with cephalosporin conjugated prodrugs resulted in dramatic cellular cytotoxicity. Thus, this two step human suicide gene therapy strategy involves 1) the transfer ofthe β-lactamase type 1 gene to cancer cells, and 2) systemic admimstration of a cephalosporin conjugated prodrug.

Claims

WHAT IS CLAIMED IS:

1. Ametliod of inducing cellular cytotoxicity of a tumor cell, comprising the steps of introducing into the tumor cell a: A) rephcation-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region ofthe genome and an insertion within the region of a nucleic acid encoding an Escherichi coli β- lacta ase under the control of a Rous Sarcoma Virus promoter; and B) prodrug having an active site which is masked by β-lactamase, whereby a functional ^β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby inducing cellular cytotoxicity of the tumor cell,

2. The method of claim 1, wherein the tumor cell is a brain, bladder, or prostate tumor cell.

3. The method of claim 1 , wherein the vector comprises Escherichi coli β- lactamase isoenzyme type 1 (E.C. 3.5.2.6).

4. The method of claim 1 , wherein the prodrug comprises a cephalosporin or cephalosporin isoenzyme, mustard, or derivative thereof, congugated to a toxic agent.

5. The method of claim 1 , wherein the toxic agent is an agent which kills the cell.

, The method of claim 5, wherein the agent is 5-fluorouracil, methottexate, adriamycin, or a chemotherapeutic agent.

7. A method ofinducing cellular cytotoxicity ofa tumor cell, comprising the steps of introducing into the tumor cell a: A) replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region ofthe genome and an insertion within the region of a nucleic acid encoding an Escherichi coli β- lactamase under the control of a Mouse Mammary Tumor Virus promoter; and B) prodrug having an active site which is masked by β-lactamase, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby inducing cellular cytotoxicity ofthe tumor cell.

8. The method of claim 7, wherein the tumor cell is a brain, bladder or prostate tumor cell.

9. The method of claim 7, wherein the vector comprises Escherichi coli β- lactamase isoenzyme type 1 (E.C. 3.5.2.6).

10. The method of claim 7, wherein the prodrug comprises a cephalosporin or cephalosporin isoenzyme, mustard, or derivative thereof, congugated to a toxic agent.

11. The method of claim 7, wherein the toxic agent is an agent which kills the cell.

12. The method of claim 11 , wherein the agent is 5-fluorouracil, methotrexate, adriamycin, or a chemotherapeutic agent.

1 A method of treating a subject with cancer, comprising the steps of administering to the subject a: 1) pharmaceutical composition comprising an effective amount of a replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an El and E3 region of the genome and an insertion within the region of a nucleic acid encoding an Escherichi coli β-lactamase under the control of a Rous Sarcoma Virus promoter and a suitable diluent or carrier; and 2) a pharmaceutical composition comprising an effective amount of a prodrug having an active site which is masked by β-lactamase and a diluent or carrier, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby treating the subject with cancer.

13. The method of claim 12, wherem the tumor cell is a brain, bladder, or prostate tumor cell.

14. The method of claim 12, wherein the vector comprises Escherichi coli β- lactamase isoenzyme type 1 (E.C. 3.5.2.6),

15. The metliod of claim 12, wherein the prodrug comprises a cephalosporin or cephalosporin isoenzyme, mustard, or derivative thereof, congugated to a toxic agent.

1 . The metliod of claim 12, wherein the toxic agent is an agent which kills the cell.

17. The method of claim 16, wherem the agent is 5-fluorOuracil, methotrexate, adriamycin, or a chemotherapeutic agent.

18. The method of claim 17, further comprising the step oftreatingthe subject with chemotherapy, radiation or chemopreventative therapies.

19. The method of claim 12, wherein the pharmaceutical composition is administered intratumorally, parenterally, paracancerally, transmucosally, transdermally, systemically, intramuscularly, intravenously, intradermally, subcutaneously, intxaperitonealy, intraventricularly, or intracranially.

20. A method of treating a subject with cancer, comprising the steps of administering to the subject a: 1) pharmaceutical composition comprising an effective amount of a rephcation-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in anEl and E3 region of the genome and an insertion within the region of a nucleic acid encoding an Escherichi coh β-lactamase under the control of a Mouse mammary Tumor Virus promoter and a suitable diluent or carrier; and 2) a pharmaceutical composition comprising an effective amount of a prodrug having an active site which is masked by β-lactamase and a diluent or carrier, whereby a functional β-lactamase is expressed from the vector so as to activate the prodrug into an agent toxic to the cells, thereby treating the subject with cancer.

21. The method of claim 20, wherein the tumor cell is a brain, bladder, or prostate tumor cell.

22. The method of claim 20, wherein the vector comprises Escherichi coli β- lactamase isoenzyme type 1 (E,C. 3.5.2.6).

23. The method of claim 20, wherein the prodrug comprises a cephalosporin or cephalosporin isoenzyme, mustard, or derivative thereof; congugated to a toxic agent.

24, The method of claim 23 , wherein the toxic agent is an agent which kills the cell.

25. The method of claim 24, wherein the agent is 5-fluorouracil, methotrexate, adriamycin, or a chemotherapeutic agent.

26. The method of claim 25, further comprising the step of treating the subject with chemotherapy, radiation or chemopreventative therapies,

27. A replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an E 1 and E3 region of the genome and an insertion within the region of a nucleic acid encoding an Escherichi coli β-lactamase under the control of a Rous S rcoma Virus promoter.

28. The replication-deficient adenovirus type 5 expression vector of claim 36, wherein the Escherichi coh β-lactamase is Escherichi coli β-lactamase isoenzyme type 1 (E.C. 3.5.2.6).

29. A pharmaceutical composition comprising the replication-deficient adenovirus type 5 expression vector of claim 28 and a suitable diluent or carrier.

30. A replication-deficient adenovirus type 5 expression vector which comprises an adenovirus genome having a deletion in an E 1 and E3 region of the genome and an insertion within the region of a nucleic acid encoding an Escherichi coli β-lactamase under the control of a Mouse Mammary Tumor Virus promoter.

31. The replication-deficient adenovirus type 5 expression vector of claim 30, wherein the Escherichi coli β-lactamase is Escherichi coli β-lactamase isoenzyme type 1 (E.C. 3.5.2.6).

32. A pharmaceutical composition comprising the rephcation-deficient adenovirus type 5 expression vector of claim 30 and a suitable diluent or carrier.