WO2004024881A2 - Ldlr utilise en tant que modificateur de la voie p53 et procedes d'utilisation associes - Google Patents

Ldlr utilise en tant que modificateur de la voie p53 et procedes d'utilisation associes Download PDF

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WO2004024881A2
WO2004024881A2 PCT/US2003/028902 US0328902W WO2004024881A2 WO 2004024881 A2 WO2004024881 A2 WO 2004024881A2 US 0328902 W US0328902 W US 0328902W WO 2004024881 A2 WO2004024881 A2 WO 2004024881A2
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ldlr
assay
agent
cell
candidate
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WO2004024881A3 (fr
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Michael Costa
Mark E. Maxwell
Mark R. Lackner
Tak Hung
Carol L. O'brien
Kim Lickteig
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Exelixis, Inc.
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
    • G01N33/50—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing
    • G01N33/5005—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells
    • G01N33/5008—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells for testing or evaluating the effect of chemical or biological compounds, e.g. drugs, cosmetics
    • G01N33/5011—Chemical analysis of biological material, e.g. blood, urine; Testing involving biospecific ligand binding methods; Immunological testing involving human or animal cells for testing or evaluating the effect of chemical or biological compounds, e.g. drugs, cosmetics for testing antineoplastic activity
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/46—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates
    • C07K14/47—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates from mammals
    • C07K14/4701—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates from mammals not used
    • C07K14/4702—Regulators; Modulating activity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2510/00—Detection of programmed cell death, i.e. apoptosis

Definitions

  • the p53 gene is mutated in over 50 different types of human cancers, including familial and spontaneous cancers, and is believed to be the most commonly mutated gene in human cancer (Zambetti and Levine, FASEB (1993) 7:855-865; Hollstein, et al., Nucleic Acids Res. (1994) 22:3551-3555). Greater than 90% of mutations in the p53 gene are missense mutations that alter a single amino acid that inactivates p53 function.
  • the human p53 protein normally functions as a central integrator of signals including DNA damage, hypoxia, nucleotide deprivation, and oncogene activation (Prives, Cell (1998) 95:5-8). In response to these signals, p53 protein levels are greatly increased with the result that the accumulated p53 activates cell cycle arrest or apoptosis depending on the nature and strength of these signals. Indeed, multiple lines of experimental evidence have pointed to a key role for p53 as a tumor suppressor (Levine, Cell (1997) 88:323-331). For example, homozygous p53 "knockout" mice are developmentally normal but exhibit nearly 100% incidence of neoplasia in the first year of life (Donehower et al, Nature (1992) 356:215-221).
  • p53 function is its activity as a gene-specific transcriptional activator.
  • genes with known p53-response elements are several with well-characterized roles in either regulation of the cell cycle or apoptosis, including GADD45, p21/Waf 1/Cipl, cyclin G, Bax, IGF-BP3, and MDM2 (Levine, Cell (1997) 88:323-331).
  • LDLR low density lipoprotein receptor
  • VLDLR very low density lipoprotein receptor
  • Variations in VLDLR may contribute to susceptibility to Alzheimer disease, dementia, and atherosclerosis (Okuizumi, K. et al (1995) Nat Genet 11:207-9; Hong, S. E. et al (2000) Nat Genet 26:93-6; Helbecque, N. et al. (2001) Neurology 56: 1183-8).
  • Apolipoprotein E is a 34-kD lipophilic protein that mediates high-affinity binding of APOE-containing lipoproteins to the LDLR and VLDLR.
  • LRP8 low density lipoprotein receptor-related protein 8; APOER2
  • APOER2 low density lipoprotein receptor-related protein 8
  • Layering of neurons in the cerebral cortex and cerebellum requires reelin (RELN), an extracellular matrix protein, mammalian disabled (DAB1), a cytosolic protein that activates tyrosine kinases, VLDLR, and APOER2.
  • VLDLR and APOER2 participate in transmitting the extracellular RELN signal to intracellular signaling processes initiated by DAB1 (Trommsdorff, M. et al (1999) Cell 97: 689-701).
  • DAB1 Duplex Activated Cell 97: 689-701
  • the ability to manipulate the genomes of model organisms such as C. elegans provides a powerful means to analyze biochemical processes that, due to significant evolutionary conservation, have direct relevance to more complex vertebrate organisms.
  • a genetic screen can be carried out in an invertebrate model organism having underexpression (e.g. knockout) or overexpression of a gene (referred to as a "genetic entry point") that yields a visible phenotype. Additional genes are mutated in a random or targeted manner.
  • a gene mutation changes the original phenotype caused by the mutation in the genetic entry point, the gene is identified as a "modifier" involved in the same or overlapping pathway as the genetic entry point.
  • modifier genes can be identified that may be attractive candidate targets for novel therapeutics.
  • LDLR low density lipoprotein receptor
  • the invention provides methods for utilizing these p53 modifier genes and polypeptides to identify LDLR-modulating agents that are candidate therapeutic agents that can be used in the treatment of disorders associated with defective or impaired p53 function and/or LDLR function.
  • Preferred LDLR-modulating agents specifically bind to LDLR polypeptides and restore p53 function.
  • Other preferred LDLR-modulating agents are nucleic acid modulators such as antisense oligomers and RNAi that repress LDLR gene expression or product activity by, for example, binding to and inhibiting the respective nucleic acid (i.e. DNA or mRNA).
  • LDLR modulating agents may be evaluated by any convenient in vitro or in vivo assay for molecular interaction with an LDLR polypeptide or nucleic acid.
  • candidate LDLR modulating agents are tested with an assay system comprising a LDLR polypeptide or nucleic acid.
  • Agents that produce a change in the activity of the assay system relative to controls are identified as candidate p53 modulating agents.
  • the assay system may be cell-based or cell-free.
  • LDLR-modulating agents include LDLR related proteins (e.g.
  • LDLR -specific antibodies LDLR -specific antisense oligomers and other nucleic acid modulators
  • chemical agents that specifically bind to or interact with LDLR or compete with LDLR binding partner (e.g. by binding to an LDLR binding partner).
  • a small molecule modulator is identified using a binding assay.
  • the screening assay system is selected from an apoptosis assay, a cell proliferation assay, an angiogenesis assay, and a hypoxic induction assay.
  • candidate p53 pathway modulating agents are further tested using a second assay system that detects changes in the p53 pathway, such as angiogenic, apoptotic, or cell proliferation changes produced by the originally identified candidate agent or an agent derived from the original agent.
  • the second assay system may use cultured cells or non-human animals.
  • the secondary assay system uses non-human animals, including animals predetermined to have a disease or disorder implicating the p53 pathway, such as an angiogenic, apoptotic, or cell proliferation disorder (e.g. cancer).
  • the invention further provides methods for modulating the LDLR function and/or the p53 pathway in a mammalian cell by contacting the mammalian cell with an agent that specifically binds a LDLR polypeptide or nucleic acid.
  • the agent may be a small molecule modulator, a nucleic acid modulator, or an antibody and may be administered to a mammalian animal predetermined to have a pathology associated the p53 pathway.
  • RNA inhibition Methods for using RNAi to silence genes in C. elegans are known in the art (Fire A, et al., 1998 Nature 391:806-811; Fire, A. Trends Genet. 15, 358-363 (1999); WO9932619). Genes causing altered phenotypes in the worms were identified as modifiers of the p53 pathway. A modifier of particular interest, T13C2.6, was identified followed by identification of the orthologs.
  • LDLR genes i.e., nucleic acids and polypeptides
  • pathologies associated with a defective p53 signaling pathway such as cancer.
  • in vitro and in vivo methods of assessing LDLR function are provided herein.
  • Modulation of the LDLR or their respective binding partners is useful for understanding the association of the p53 pathway and its members in normal and disease conditions and for developing diagnostics and therapeutic modalities for p53 related pathologies.
  • LDLR- modulating agents that act by inhibiting or enhancing LDLR expression, directly or indirectly, for example, by affecting an LDLR function such as binding activity, can be identified using methods provided herein. LDLR modulating agents are useful in diagnosis, therapy and pharmaceutical development.
  • Nucleic acids and polypeptides of the invention Sequences related to LDLR nucleic acids and polypeptides that can be used in the invention are disclosed in Genbank (referenced by Genbank identifier (GI) number) as GI#s 15451869 (SEQ ID NO:l), 15451865 (SEQ ID NO:2), 15451867 (SEQ ID NOS), 1834533 (SEQ ID NO:4), 1321643 (SEQ ID NO:5), 21755990 (SEQ ID NO:6), 30354633 (SEQ H NO7:), 5803130 (SEQ ID NO:8), and 391733 (SEQ ID NO:9) for nucleic acid, and GI#s 4758688 (SEQ ID NO: 10) and 4507901 (SEQ ID NO: 11) for polypeptides.
  • Genbank referenced by Genbank identifier (GI) number
  • LDLR polypeptide refers to a full-length LDLR protein or a functionally active fragment or derivative thereof.
  • a "functionally active" LDLR fragment or derivative exhibits one or more functional activities associated with a full- length, wild-type LDLR protein, such as antigenic or immunogenic activity, ability to bind natural cellular substrates, etc.
  • the functional activity of LDLR proteins, derivatives and fragments can be assayed by various methods known to one skilled in the art (Current Protocols in Protein Science (1998) Coligan et al, eds., John Wiley & Sons, Inc., Somerset, New Jersey) and as further discussed below.
  • a functionally active LDLR polypeptide is a LDLR derivative capable of rescuing defective endogenous LDLR activity, such as in cell based or animal assays; the rescuing derivative may be from the same or a different species.
  • functionally active fragments also include those fragments that comprise one or more structural domains of an LDLR, such as a binding domain. Protein domains can be identified using the PFAM program
  • the Low-density lipoprotein receptor domain class a (PFAM 00057) of LDLR from GI# 4758688 (SEQ ID NO: 10) is located at approximately amino acid residues 45 to 83, 84 to 124, 125 to 165, 167 to 203, 204 to 247, 257 to 296, 297 to 335
  • Low-density lipoprotein receptor domain class b (PFAM 00058) of the same protein is located at approximately amino acid residues 462 to 507, 509 to 550, 552 to 594, 596 to 639, 640 to 680.
  • preferred fragments are functionally active, domain-containing fragments comprising at least 25 contiguous amino acids, preferably at least 50, more preferably 75, and most preferably at least 100 contiguous amino acids of any one of SEQ ID NOs: 10-11 (an
  • the fragment comprises the entire functionally active domain.
  • LDLR nucleic acid refers to a DNA or RNA molecule that encodes a LDLR polypeptide.
  • the LDLR polypeptide or nucleic acid or fragment thereof is from a human, but can also be an ortholog, or derivative thereof with at least 70% sequence identity, preferably at least 80%, more preferably 85%, still more preferably 90%, and most preferably at least 95% sequence identity with human LDLR.
  • Methods of identifying orthlogs are known in the art. Normally, orthologs in different species retain the same function, due to presence of one or more protein motifs and/or 3-dimensional structures. Orthologs are generally identified by sequence homology analysis, such as BLAST analysis, usually using protein bait sequences.
  • Sequences are assigned as a potential ortholog if the best hit sequence from the forward BLAST result retrieves the original query sequence in the reverse BLAST (Huynen MA and Bork P, Proc Natl Acad Sci (1998) 95:5849-5856; Huynen MA et al, Genome Research (2000) 10:1204-1210).
  • Programs for multiple sequence alignment such as CLUSTAL (Thompson JD et al, 1994, Nucleic Acids Res 22:4673-4680) may be used to highlight conserved regions and/or residues of orthologous proteins and to generate phylogenetic trees.
  • orthologous sequences from two species generally appear closest on the tree with respect to all other sequences from these two species.
  • Structural threading or other analysis of protein folding e.g., using software by ProCeryon, Biosciences, Salzburg, Austria
  • protein folding may also identify potential orthologs.
  • a gene duplication event follows speciation, a single gene in one species, such as C. elegans, may correspond to multiple genes (paralogs) in another, such as human.
  • the term "orthologs" encompasses paralogs.
  • percent (%) sequence identity with respect to a subject sequence, or a specified portion of a subject sequence, is defined as the percentage of nucleotides or amino acids in the candidate derivative sequence identical with the nucleotides or amino acids in the subject sequence (or specified portion thereof), after aligning the sequences and introducing gaps, if necessary to achieve the maximum percent sequence identity, as generated by the program WU-BLA.ST-2.0al9 (Altschul et al, J. Mol. Biol. (1997) 215:403-410) with all the search parameters set to default values.
  • the HSP S and HSP S2 parameters are dynamic values and are established by the program itself depending upon the composition of the particular sequence and composition of the particular database against which the sequence of interest is being searched.
  • a % identity value is determined by the number of matching identical nucleotides or amino acids divided by the sequence length for which the percent identity is being reported. "Percent (%) amino acid sequence similarity" is determined by doing the same calculation as for determining % amino acid sequence identity, but including conservative amino acid substitutions in addition to identical amino acids in the computation.
  • Aromatic amino acids that can be substituted for each other are phenylalanine, tryptophan, and tyrosine; interchangeable hydrophobic amino acids are leucine, isoleucine, methionine, and valine; interchangeable polar amino acids are glutamine and asparagine; interchangeable basic amino acids are arginine, lysine and histidine; interchangeable acidic amino acids are aspartic acid and glutamic acid; and interchangeable small amino acids are alanine, serine, threonine, cysteine and glycine.
  • an alignment for nucleic acid sequences is provided by the local homology algorithm of Smith and Waterman (Smith and Waterman, 1981, Advances in Applied Mathematics 2:482-489; database: European Bioinformatics Institute; Smith and Waterman, 1981, J. of Molec.Biol., 147:195-197; Nicholas et al., 1998, "A tutorial on Searching Sequence Databases and Sequence Scoring Methods” (www.psc.edu) and references cited therein.; W.R. Pearson, 1991, Genomics 11:635-650).
  • This algorithm can be applied to amino acid sequences by using the scoring matrix developed by Dayhoff (Dayhoff: Atlas of Protein Sequences and Structure, M. O. Dayhoff ed., 5 suppl.
  • Derivative nucleic acid molecules of the subject nucleic acid molecules include sequences that hybridize to the nucleic acid sequence of SEQ ID NOs: 1-9.
  • the stringency of hybridization can be controlled by temperature, ionic strength, pH, and the presence of denaturing agents such as formamide during hybridization and washing. Conditions routinely used are set out in readily available procedure texts (e.g., Current Protocol in Molecular Biology, Vol. 1, Chap. 2.10, John Wiley & Sons, Publishers (1994); Sambrook et al, Molecular Cloning, Cold Spring Harbor (1989)).
  • a nucleic acid molecule of the invention is capable of hybridizing to a nucleic acid molecule containing the nucleotide sequence of any one of SEQ JD NOs: 1-9 under high stringency hybridization conditions that are: prehybridization of filters containing nucleic acid for 8 hours to overnight at 65° C in a solution comprising 6X single strength citrate (SSC) (IX SSC is 0.15 M NaCl, 0.015 M Na citrate; pH 7.0), 5X Denhardt's solution, 0.05% sodium pyrophosphate and 100 ⁇ g/ml herring sperm DNA; hybridization for 18-20 hours at 65° C in a solution containing 6X SSC, IX Denhardt's solution, 100 /xg/ml yeast tRNA and 0.05% sodium pyrophosphate; and washing of filters at 65° C for lh in a solution containing 0.1X SSC and 0.1% SDS (sodium dodecyl sulfate).
  • SSC
  • moderately stringent hybridization conditions are used that are: pretreatment of filters containing nucleic acid for 6 h at 40° C in a solution containing 35% formamide, 5X SSC, 50 mM Tris-HCl (pH7.5), 5mM EDTA, 0.1% PVP, 0.1% Ficoll, 1% BSA, and 500 ⁇ g/ml denatured salmon sperm DNA; hybridization for 18-20h at 40° C in a solution containing 35% formamide, 5X SSC, 50 mM Tris-HCl (pH7.5), 5mM EDTA, 0.02% PVP, 0.02% Ficoll, 0.2% BSA, 100 ⁇ g/ml salmon sperm DNA, and 10% (wt/vol) dextran sulfate; followed by washing twice for 1 hour at 55° C in a solution containing 2X SSC and 0.1% SDS.
  • low stringency conditions can be used that are: incubation for 8 hours to overnight at 37° C in a solution comprising 20% formamide, 5 x SSC, 50 mM sodium phosphate (pH 7.6), 5X Denhardt's solution, 10% dextran sulfate, and 20 ⁇ g/ml denatured sheared salmon sperm DNA; hybridization in the same buffer for 18 to 20 hours; and washing of filters in 1 x SSC at about 37° C for 1 hour.
  • LDLR nucleic acids and polypeptides are useful for identifying and testing agents that modulate LDLR function and for other applications related to the involvement of LDLR in the p53 pathway.
  • LDLR nucleic acids and derivatives and orthologs thereof may be obtained using any available method. For instance, techniques for isolating cDNA or genomic DNA sequences of interest by screening DNA libraries or by using polymerase chain reaction (PCR) are well known in the art.
  • PCR polymerase chain reaction
  • the particular use for the protein will dictate the particulars of expression, production, and purification methods. For instance, production of proteins for use in screening for modulating agents may require methods that preserve specific biological activities of these proteins, whereas production of proteins for antibody generation may require structural integrity of particular epitopes.
  • LDLR protein for assays used to assess LDLR function, such as involvement in cell cycle regulation or hypoxic response, may require expression in eukaryotic cell lines capable of these cellular activities.
  • recombinant LDLR is expressed in a cell line known to have defective p53 function (e.g.
  • SAOS-2 osteoblasts H1299 lung cancer cells, C33A and HT3 cervical cancer cells, HT-29 and DLD-1 colon cancer cells, among others, available from American Type Culture Collection (ATCC), Manassas, VA).
  • ATCC American Type Culture Collection
  • VA Manassas
  • the recombinant cells are used in cell-based screening assay systems of the invention, as described further below.
  • the nucleotide sequence encoding an LDLR polypeptide can be inserted into any appropriate expression vector.
  • the necessary transcriptional and translational signals including promoter/enhancer element, can derive from the native LDLR gene and/or its flanking regions or can be heterologous.
  • a variety of host-vector expression systems may be utilized, such as mammalian cell systems infected with virus (e.g.
  • vaccinia virus adeno virus, etc.
  • insect cell systems infected with virus e.g. baculo virus
  • microorganisms such as yeast containing yeast vectors, or bacteria transformed with bacteriophage, plasmid, or cosmid DNA.
  • An isolated host cell strain that modulates the expression of, modifies, and/or specifically processes the gene product may be used.
  • the expression vector can comprise a promoter operably linked to an LDLR gene nucleic acid, one or more origins of replication, and, one or more selectable markers (e.g. thymidine kinase activity, resistance to antibiotics, etc.).
  • selectable markers e.g. thymidine kinase activity, resistance to antibiotics, etc.
  • recombinant expression vectors can be identified by assaying for the expression of the LDLR gene product based on the physical or functional properties of the LDLR protein in in vitro assay systems (e.g. immunoassays).
  • the LDLR protein, fragment, or derivative may be optionally expressed as a fusion, or chimeric protein product (i.e.
  • a chimeric product can be made by ligating the appropriate nucleic acid sequences encoding the desired amino acid sequences to each other using standard methods and expressing the chimeric product.
  • a chimeric product may also be made by protein synthetic techniques, e.g. by use of a peptide synthesizer (Hunkapiller et al, Nature (1984) 310:105-111).
  • the gene product can be isolated and purified using standard methods (e.g. ion exchange, affinity, and gel exclusion chromatography; centrifugation; differential solubility; electrophoresis).
  • native LDLR proteins can be purified from natural sources, by standard methods (e.g. immunoaffinity purification). Once a protein is obtained, it may be quantified and its activity measured by appropriate methods, such as immunoassay, bioassay, or other measurements of physical properties, such as crystallography.
  • mis-expression encompasses ectopic expression, over- expression, under-expression, and non-expression (e.g. by gene knock-out or blocking expression that would otherwise normally occur).
  • Animal models that have been genetically modified to alter LDLR expression may be used in in vivo assays to test for activity of a candidate p53 modulating agent, or to further assess the role of LDLR in a p53 pathway process such as apoptosis or cell proliferation.
  • the altered LDLR expression results in a detectable phenotype, such as decreased or increased levels of cell proliferation, angiogenesis, or apoptosis compared to control animals having normal LDLR expression.
  • the genetically modified animal may additionally have altered p53 expression (e.g. p53 knockout).
  • Preferred genetically modified animals are mammals such as primates, rodents (preferably mice or rats), among others.
  • Preferred non-mammalian species include zebrafish, C.
  • Preferred genetically modified animals are transgenic animals having a heterologous nucleic acid sequence present as an extrachromosomal element in a portion of its cells, i.e. mosaic animals (see, for example, techniques described by Jakobovits, 1994, Curr. Biol. 4:761-763.) or stably integrated into its germ line DNA (i.e., in the genomic sequence of most or all of its cells).
  • Heterologous nucleic acid is introduced into the germ line of such transgenic animals by genetic manipulation of, for example, embryos or embryonic stem cells of the host animal. Methods of making transgenic animals are well-known in the art (for transgenic mice see Brinster et al., Proc. Nat.
  • the transgenic animal is a "knock-out" animal having a heterozygous or homozygous alteration in the sequence of an endogenous LDLR gene that results in a decrease of LDLR function, preferably such that LDLR expression is undetectable or insignificant.
  • Knock-out animals are typically generated by homologous recombination with a vector comprising a transgene having at least a portion of the gene to be knocked out. Typically a deletion, addition or substitution has been introduced into the transgene to functionally disrupt it.
  • the transgene can be a human gene (e.g., from a human genomic clone) but more preferably is an ortholog of the human gene derived from the transgenic host species.
  • a mouse LDLR gene is used to construct a homologous recombination vector suitable for altering an endogenous LDLR gene in the mouse genome.
  • homologous recombination vector suitable for altering an endogenous LDLR gene in the mouse genome.
  • Detailed methodologies for homologous recombination in mice are available (see Capecchi, Science (1989) 244: 1288-1292; Joyner et al, Nature (1989)
  • knock-out animals such as mice harboring a knockout of a specific gene, may be used to produce antibodies against the human counterpart of the gene that has been knocked out (Claesson MH et al, (1994) Scan J Immunol 40:257-264; Declerck PJ et al., (1995) J Biol Chem. 270:8397-400).
  • the transgenic animal is a "knock-in" animal having an alteration in its genome that results in altered expression (e.g., increased (including ectopic) or decreased expression) of the LDLR gene, e.g., by introduction of additional copies of LDLR, or by operatively inserting a regulatory sequence that provides for altered expression of an endogenous copy of the LDLR gene.
  • a regulatory sequence include inducible, tissue-specific, and constitutive promoters and enhancer elements.
  • the knock- in can be homozygous or heterozygous.
  • Transgenic nonhuman animals can also be produced that contain selected systems allowing for regulated expression of the transgene.
  • a system that may be produced is the cre/loxP recombinase system of bacteriophage PI (Lakso et al, PNAS (1992) 89:6232-6236; U.S. Pat. No. 4,959,317). If a cre/loxP recombinase system is used to regulate expression of the transgene, animals containing transgenes encoding both the Cre recombinase and a selected protein are required.
  • Such animals can be provided through the construction of "double" transgenic animals, e.g., by mating two transgenic animals, one containing a transgene encoding a selected protein and the other containing a transgene encoding a recombinase.
  • a recombinase system is the FLP recombinase system of Saccharomyces cerevisiae (O'Gorman et al. (1991) Science 251:1351-1355; U.S. Pat. No. 5,654,182).
  • both Cre-LoxP and Flp-Frt are used in the same system to regulate expression of the transgene, and for sequential deletion of vector sequences in the same cell (Sun X et al (2000) Nat Genet 25:83-6).
  • the genetically modified animals can be used in genetic studies to further elucidate the p53 pathway, as animal models of disease and disorders implicating defective p53 function, and for in vivo testing of candidate therapeutic agents, such as those identified in screens described below.
  • the candidate therapeutic agents are administered to a genetically modified animal having altered LDLR function and phenotypic changes are compared with appropriate control animals such as genetically modified animals that receive placebo treatment, and/or animals with unaltered LDLR expression that receive candidate therapeutic agent.
  • animal models having defective p53 function can be used in the methods of the present invention.
  • a p53 knockout mouse can be used to assess, in vivo, the activity of a candidate p53 modulating agent identified in one of the in vitro assays described below.
  • p53 knockout mice are > described in the literature (Jacks et al., Nature 2001;410:1111-1116, 1043-1044; Donehower et al, supra).
  • the candidate p53 modulating agent when administered to a model system with cells defective in p53 function, produces a detectable phenotypic change in the model system indicating that the p53 function is restored, i.e., the cells exhibit normal cell cycle progression.
  • the invention provides methods to identify agents that interact with and/or modulate the function of LDLR and/or the p53 pathway. Modulating agents identified by the methods are also part of the invention. Such agents are useful in a variety of diagnostic and therapeutic applications associated with the p53 pathway, as well as in further analysis of the LDLR protein and its contribution to the p53 pathway.
  • the invention also provides methods for modulating the p53 pathway comprising the step of specifically modulating LDLR activity by administering a LDLR- interacting or -modulating agent.
  • an "LDLR-modulating agent” is any agent that modulates LDLR function, for example, an agent that interacts with LDLR to inhibit or enhance LDLR activity or otherwise affect normal LDLR function.
  • LDLR function can be affected at any level, including transcription, protein expression, protein localization, and cellular or extra-cellular activity.
  • the LDLR - modulating agent specifically modulates the function of the LDLR.
  • the phrases "specific modulating agent”, “specifically modulates”, etc., are used herein to refer to modulating agents that directly bind to the LDLR polypeptide or nucleic acid, and preferably inhibit, enhance, or otherwise alter, the function of the LDLR.
  • the LDLR- modulating agent is a modulator of the p53 pathway (e.g. it restores and/or upregulates p53 function) and thus is also a p53-modulating agent.
  • Preferred LDLR-modulating agents include small molecule compounds; LDLR- interacting proteins, including antibodies and other biotherapeutics; and nucleic acid modulators such as antisense and RNA inhibitors.
  • the modulating agents may be formulated in pharmaceutical compositions, for example, as compositions that may comprise other active ingredients, as in combination therapy, and/or suitable carriers or excipients. Techniques for formulation and administration of the compounds may be found in "Remington's Pharmaceutical Sciences” Mack Publishing Co., Easton, PA, 19' th edition.
  • Small molecule modulators Small molecules are often preferred to modulate function of proteins with enzymatic function, and/or containing protein interaction domains.
  • Chemical agents referred to in the art as "small molecule” compounds are typically organic, non-peptide molecules, having a molecular weight less than 10,000, preferably less than 5,000, more preferably less than 1,000, and most preferably less than 500 daltons.
  • This class of modulators includes chemically synthesized molecules, for instance, compounds from combinatorial chemical libraries. Synthetic compounds may be rationally designed or identified based on known or inferred properties of the LDLR protein or may be identified by screening compound libraries.
  • modulators of this class are natural products, particularly secondary metabolites from organisms such as plants or fungi, which can also be identified by screening compound libraries for LDLR- modulating activity. Methods for generating and obtaining compounds are well known in the art (Schreiber SL, Science (2000) 151: 1964-1969; Radmann J and Gunther J, Science (2000) 151:1947-1948).
  • Small molecule modulators identified from screening assays, as described below, can be used as lead compounds from which candidate clinical compounds may be designed, optimized, and synthesized. Such clinical compounds may have utility in treating pathologies associated with the p53 pathway.
  • the activity of candidate small molecule modulating agents may be improved several-fold through iterative secondary functional validation, as further described below, structure determination, and candidate modulator modification and testing.
  • candidate clinical compounds are generated with specific regard to clinical and pharmacological properties.
  • the reagents may be derivatized and re-screened using in vitro and in vivo assays to optimize activity and minimize toxicity for pharmaceutical development.
  • LDLR-interacting proteins are useful in a variety of diagnostic and therapeutic applications related to the p53 pathway and related disorders, as well as in validation assays for other LDLR-modulating agents.
  • LDLR- interacting proteins affect normal LDLR function, including transcription, protein expression, protein localization, and cellular or extra-cellular activity.
  • LDLR-interacting proteins are useful in detecting and providing information about the function of LDLR proteins, as is relevant to p53 related disorders, such as cancer (e.g., for diagnostic means).
  • An LDLR-interacting protein may be endogenous, i.e.
  • LDLR-modulators include dominant negative forms of LDLR-interacting proteins and of LDLR proteins themselves.
  • Yeast two-hybrid and variant screens offer preferred methods for identifying endogenous LDLR-interacting proteins (Finley, R. L. et al. (1996) in DNA Cloning-Expression
  • Mass spectrometry is an alternative preferred method for the elucidation of protein complexes (reviewed in, e.g., Pandley A and Mann M, Nature (2000) 405:837-846; Yates JR 3 rd , Trends Genet (2000) 16:5-8).
  • An LDLR-interacting protein may be an exogenous protein, such as an LDLR-specific antibody or a T-cell antigen receptor (see, e.g., Harlow and Lane (1988) Antibodies, A Laboratory Manual, Cold Spring Harbor Laboratory; Harlow and Lane (1999) Using antibodies: a laboratory manual. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press). LDLR antibodies are further discussed below.
  • an LDLR-interacting protein specifically binds an LDLR protein.
  • an LDLR-modulating agent binds an LDLR substrate, binding partner, or cofacto .
  • the protein modulator is an LDLR specific antibody agonist or antagonist.
  • the antibodies have therapeutic and diagnostic utilities, and can be used in screening assays to identify LDLR modulators.
  • the antibodies can also be used in dissecting the portions of the LDLR pathway responsible for various cellular responses and in the general processing and maturation of the LDLR.
  • Antibodies that specifically bind LDLR polypeptides can be generated using known methods.
  • the antibody is specific to a mammalian ortholog of LDLR polypeptide, and more preferably, to human LDLR.
  • Antibodies may be polyclonal, monoclonal (mAbs), humanized or chimeric antibodies, single chain antibodies, Fab fragments, F(ab').sub.2 fragments, fragments produced by a FAb expression library, anti- idiotypic (anti-Id) antibodies, and epitope-binding fragments of any of the above.
  • Epitopes of LDLR which are particularly antigenic can be selected, for example, by routine screening of LDLR polypeptides for antigenicity or by applying a theoretical method for selecting antigenic regions of a protein (Hopp and Wood (1981), Proc. Nati. Acad. Sci. U.S.A. 78:3824-28; Hopp and Wood, (1983) Mol. Immunol. 20:483-89; Sutcliffe et al., (1983) Science 219:660-66) to the amino acid sequence shown in SEQ ID NOs: 10-11.
  • Monoclonal antibodies with affinities of 10 8 M “1 preferably 10 9 M “1 to 10 10 M “1 , or stronger can be made by standard procedures as described (Harlow and Lane, supra; Goding (1986) Monoclonal Antibodies: Principles and Practice (2d ed) Academic Press, New York; and U.S. Pat. Nos. 4,381,292; 4,451,570; and 4,618,577).
  • Antibodies may be generated against crude cell extracts of LDLR or substantially purified fragments thereof. If LDLR fragments are used, they preferably comprise at least 10, and more preferably, at least 20 contiguous amino acids of an LDLR protein.
  • LDLR-specific antigens and/or immunogens are coupled to carrier proteins that stimulate the immune response.
  • the subject polypeptides are covalently coupled to the keyhole limpet hemocyanin (KLH) carrier, and the conjugate is emulsified in Freund's complete adjuvant, which enhances the immune response.
  • KLH keyhole limpet hemocyanin
  • An appropriate immune system such as a laboratory rabbit or mouse is immunized according to conventional protocols.
  • LDLR-specific antibodies is assayed by an appropriate assay such as a solid phase enzyme-linked immunosorbant assay (ELISA) using immobilized corresponding LDLR polypeptides.
  • an appropriate assay such as a solid phase enzyme-linked immunosorbant assay (ELISA) using immobilized corresponding LDLR polypeptides.
  • ELISA enzyme-linked immunosorbant assay
  • Other assays such as radioimmunoassays or fluorescent assays might also be used.
  • Chimeric antibodies specific to LDLR polypeptides can be made that contain different portions from different animal species.
  • a human immunoglobulin constant region may be linked to a variable region of a murine mAb, such that the antibody derives its biological activity from the human antibody, and its binding specificity from the murine fragment.
  • Chimeric antibodies are produced by splicing together genes that encode the appropriate regions from each species (Morrison et al., Proc. Natl. Acad. Sci. (1984) 81:6851-6855; Neuberger et al., Nature (1984) 312:604-608; Takeda et al., Nature (1985) 31:452-454).
  • Humanized antibodies which are a form of chimeric antibodies, can be generated by grafting complementary-determining regions (CDRs) (Carlos, T. M., J. M. Harlan. 1994. Blood 84:2068-2101) of mouse antibodies into a background of human framework regions and constant regions by recombinant DNA technology (Riechmann LM, et al., 1988 Nature 323: 323-327). Humanized antibodies contain -10% murine sequences and ⁇ 90% human sequences, and thus further reduce or eliminate immunogenicity, while retaining the antibody specificities (Co MS, and Queen C. 1991 Nature 351: 501-501; Morrison SL. 1992 Ann. Rev. Immun. 10:239-265). Humanized antibodies and methods of their production are well-known in the art (U.S. Pat. Nos. 5,530,101, 5,585,089, 5,693,762, and 6,180,370).
  • LDLR-specific single chain antibodies which are recombinant, single chain polypeptides formed by linking the heavy and light chain fragments of the Fv regions via an amino acid bridge, can be produced by methods known in the art (U.S. Pat. No. 4,946,778; Bird, Science (1988) 242:423-426; Huston et al., Proc. Natl. Acad. Sci. USA (1988) 85:5879-5883; and Ward et al., Nature (1989) 334:544-546).
  • T-cell antigen receptors are included within the scope of antibody modulators (Harlow and Lane, 1988, supra).
  • polypeptides and antibodies of the present invention may be used with or without modification. Frequently, antibodies will be labeled by joining, either covalently or non-covalently, a substance that provides for a detectable signal, or that is toxic to cells that express the targeted protein (Menard S, et al., Int J. Biol Markers (1989) 4:131-134).
  • labels and conjugation techniques are known and are reported extensively in both the scientific and patent literature. Suitable labels include radionuclides, enzymes, substrates, cofactors, inhibitors, fluorescent moieties, fluorescent emitting lanthanide metals, chemiluminescent moieties, bioluminescent moieties, magnetic particles, and the like (U.S. Pat. Nos.
  • the antibodies of the subject invention are typically administered parenterally, when possible at the target site, or intravenously.
  • the therapeutically effective dose and dosage regimen is determined by clinical studies.
  • the amount of antibody administered is in the range of about 0.1 mg/kg -to about 10 mg/kg of patient weight.
  • the antibodies are formulated in a unit dosage injectable form (e.g., solution, suspension, emulsion) in association with a pharmaceutically acceptable vehicle.
  • a pharmaceutically acceptable vehicle are inherently nontoxic and non-therapeutic. Examples are water, saline, Ringer's solution, dextrose solution, and 5% human serum albumin.
  • Nonaqueous vehicles such as fixed oils, ethyl oleate, or liposome carriers may also be used.
  • the vehicle may contain minor amounts of additives, such as buffers and preservatives, which enhance isotonicity and chemical stability or otherwise enhance therapeutic potential.
  • the antibodies' concentrations in such vehicles are typically in the range of about 1 mg/ml to aboutlO mg/ml.
  • an LDLR-interacting protein may have biotherapeutic applications.
  • Biotherapeutic agents formulated in pharmaceutically acceptable carriers and dosages may be used to activate or inhibit signal transduction pathways. This modulation may be accomplished by binding a ligand, thus inhibiting the activity of the pathway; or by binding a receptor, either to inhibit activation of, or to activate, the receptor.
  • the biotherapeutic may itself be a ligand capable of activating or inhibiting a receptor. Biotherapeutic agents and methods of producing them are described in detail in U.S. Pat. No. 6,146,628.
  • LDLR its ligand(s), antibodies to the ligand(s) or the LDLR itself may be used as biotherapeutics to modulate the activity of LDLR in the p53 pathway.
  • LDLR-modulating agents comprise nucleic acid molecules, such as antisense oligomers or double stranded RNA (dsRNA), which generally inhibit LDLR activity.
  • Preferred nucleic acid modulators interfere with the function of the LDLR nucleic acid such as DNA replication, transcription, translocation of the LDLR RNA to the site of protein translation, translation of protein from the LDLR RNA, splicing of the LDLR RNA to yield one or more mRNA species, or catalytic activity which may be engaged in or facilitated by the LDLR RNA.
  • the antisense oligomer is an oligonucleotide that is sufficiently complementary to an LDLR mRNA to bind to and prevent translation, preferably by binding to the 5' untranslated region.
  • LDLR-specific antisense oligonucleotides preferably range from at least 6 to about 200 nucleotides. In some embodiments the oligonucleotide is preferably at least 10, 15, or 20 nucleotides in length. In other embodiments, the oligonucleotide is preferably less than 50, 40, or 30 nucleotides in length.
  • the oligonucleotide can be DNA or RNA or a chimeric mixture or derivatives or modified versions thereof, single-stranded or double-stranded.
  • the oligonucleotide can be modified at the base moiety, sugar moiety, or phosphate backbone.
  • the oligonucleotide may include other appending groups such as peptides, agents that facilitate transport across the cell membrane, hybridization-triggered cleavage agents, and intercalating agents.
  • the antisense oligomer is a phosphothioate morpholino oligomer (PMO).
  • PMOs are assembled from four different morpholino subunits, each of which contain one of four genetic bases (A, C, G, or T) linked to a six-membered morpholine ring. Polymers of these subunits are joined by non-ionic phosphodiamidate intersubunit linkages. Details of how to make and use PMOs and other antisense oligomers are well known in the art (e.g. see WO99/18193; Probst JC, Antisense Ohgodeoxynucleotide and Ribozyme Design, Methods. (2000) 22(3):271-281; Summerton J, and Weller D. 1997 Antisense Nucleic Acid Drug Dev. :7: 187-95; US Pat. No. 5,235,033; and US Pat No. 5,378,841).
  • RNAi is the process of sequence-specific, post-transcriptional gene silencing in animals and plants, initiated by double-stranded RNA (dsRNA) that is homologous in sequence to the silenced gene.
  • dsRNA double-stranded RNA
  • Methods relating to the use of RNAi to silence genes in C. elegans, Drosophila, plants, and humans are known in the art (Fire A, et al, 1998 Nature 391:806-811; Fire, A. Trends Genet. 15, 358-363 (1999); Sharp, P. A. RNA interference 2001. Genes Dev. 15, 485-490 (2001); Hammond, S.
  • Nucleic acid modulators are commonly used as research reagents, diagnostics, and therapeutics. For example, antisense oligonucleotides, which are able to inhibit gene expression with seventeen specificity, are often used to elucidate the function of particular genes (see, for example, U.S. Pat. No. 6,165,790). Nucleic acid modulators are also used, for example, to distinguish between functions of various members of a biological pathway.
  • an LDLR-specific nucleic acid modulator is used in an assay to further elucidate the role of the LDLR in the p53 pathway, and/or its relationship to other members of the pathway.
  • an LDLR-specific antisense oligomer is used as a therapeutic agent for treatment of p53- related disease states .
  • an "assay system” encompasses all the components required for performing and analyzing results of an assay that detects and/or measures a particular event.
  • primary assays are used to identify or confirm a modulator's specific biochemical or molecular effect with respect to the LDLR nucleic acid or protein.
  • secondary assays further assess the activity of a LDLR modulating agent identified by a primary assay and may confirm that the modulating agent affects LDLR in a manner relevant to the p53 pathway. In some cases, LDLR modulators will be directly tested in a secondary assay.
  • the screening method comprises contacting a suitable assay system comprising an LDLR polypeptide or nucleic acid with a candidate agent under conditions whereby, but for the presence of the agent, the system provides a reference activity (e.g. binding activity), which is based on the particular molecular event the screening method detects.
  • a reference activity e.g. binding activity
  • a statistically significant difference between the agent- biased activity and the reference activity indicates that the candidate agent modulates LDLR activity, and hence the p53 pathway.
  • the LDLR polypeptide or nucleic acid used in the assay may comprise any of the nucleic acids or polypeptides described above.
  • the type of modulator tested generally determines the type of primary assay.
  • screening assays are used to identify candidate modulators. Screening assays may be cell-based or may use a cell-free system that recreates or retains the relevant biochemical reaction of the target protein (reviewed in Sittampalam GS et al, Curr Opin Chem Biol (1997) 1:384-91 and accompanying references).
  • cell-based refers to assays using live cells, dead cells, or a particular cellular fraction, such as a membrane, endoplasmic reticulum, or mitochondrial fraction.
  • cell free encompasses assays using substantially purified protein (either endogenous or recombinantly produced), partially purified or crude cellular extracts.
  • Screening assays may detect a variety of molecular events, including protein-DNA interactions, protein-protein interactions (e.g., receptor-ligand binding), transcriptional activity (e.g., using a reporter gene), enzymatic activity (e.g., via a property of the substrate), activity of second messengers, immunogenicty and changes in cellular morphology or other cellular characteristics.
  • Appropriate screening assays may use a wide range of detection methods including fluorescent, radioactive, colorimetric, spectrophotometric, and amperometric methods, to provide a read-out for the particular molecular event detected.
  • Cell-based screening assays usually require systems for recombinant expression of LDLR and any auxiliary proteins demanded by the particular assay. Appropriate methods for generating recombinant proteins produce sufficient quantities of proteins that retain their relevant biological activities and are of sufficient purity to optimize activity and assure assay reproducibility. Yeast two-hybrid and variant screens, and mass spectrometry provide preferred methods for determining protein-protein interactions and elucidation of protein complexes. In certain applications, when LDLR-interacting proteins are used in screens to identify small molecule modulators, the binding specificity of the interacting protein to the LDLR protein may be assayed by various known methods such as substrate processing (e.g.
  • binding equilibrium constants usually at least about 10 7 M 1 , preferably at least about 10 8 M "1 , more preferably at least about 10 9 M "
  • immunogenicity e.g. ability to elicit LDLR specific antibody in a heterologous host such as a mouse, rat, goat or rabbit.
  • binding may be assayed by, respectively, substrate and ligand processing.
  • the screening assay may measure a candidate agent's ability to specifically bind to or modulate activity of a LDLR polypeptide, a fusion protein thereof, or to cells or membranes bearing the polypeptide or fusion protein.
  • the LDLR polypeptide can be full length or a fragment thereof that retains functional LDLR activity.
  • the LDLR polypeptide may be fused to another polypeptide, such as a peptide tag for detection or anchoring, or to another tag.
  • the LDLR polypeptide is preferably human LDLR, or is an ortholog or derivative thereof as described above.
  • the screening assay detects candidate agent-based modulation of LDLR interaction with a binding target, such as an endogenous or exogenous protein or other substrate that has LDLR -specific binding activity, and can be used to assess normal LDLR gene function.
  • a binding target such as an endogenous or exogenous protein or other substrate that has LDLR -specific binding activity
  • screening assays are high throughput or ultra high throughput and thus provide automated, cost-effective means of screening compound libraries for lead compounds (Fernandes PB, Curr Opin Chem Biol (1998) 2:597-603; Sundberg SA, Curr Opin Biotechnol 2000, 11:47-53).
  • screening assays uses fluorescence technologies, including fluorescence polarization, time-resolved fluorescence, and fluorescence resonance energy transfer.
  • a variety of suitable assay systems may be used to identify candidate LDLR and p53 pathway modulators (e.g. U.S. Pat. Nos. 5,550,019 and 6,133,437 (apoptosis assays); U.S. Pat. No. 6,020,135 (p53 modulation), and U.S. Pat. Nos. 5,976,782, 6,225,118 and 6,444,434 (angiogenesis assays), among others). Specific preferred assays are described in more detail below.
  • Apoptosis assays may be performed by terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling (TUNEL) assay.
  • TUNEL terminal deoxynucleotidyl transferase-mediated digoxigenin-11-dUTP nick end labeling
  • the TUNEL assay is used to measure nuclear DNA fragmentation characteristic of apoptosis ( Lazebnik et al, 1994, Nature 371, 346), by following the incorporation of fluorescein-dUTP (Yonehara et al, 1989, J. Exp. Med. 169, 1747).
  • Apoptosis may further be assayed by acridine orange staining of tissue culture cells (Lucas, R., et al., 1998, Blood 15:4730-41).
  • cell-based apoptosis assays include the caspase-3/7 assay and the cell death nucleosome ELIS A assay.
  • the caspase 3/7 assay is based on the activation of the caspase cleavage activity as part of a cascade of events that occur during programmed cell death in many apoptotic pathways.
  • the caspase 3/7 assay commercially available Apo- ONETM Homogeneous Caspase-3/7 assay from Promega, cat# 67790
  • lysis buffer and caspase substrate are mixed and added to cells.
  • the caspase substrate becomes fluorescent when cleaved by active caspase 3/7.
  • the nucleosome ELISA assay is a general cell death assay known to those skilled in the art, and available commercially (Roche, Cat# 1774425). This assay is a quantitative sandwich-enzyme-immunoassay which uses monoclonal antibodies directed against DNA and histones respectively, thus specifically determining amount of mono- and oligonucleosomes in the cytoplasmic fraction of cell lysates. Mono and oligonucleosomes are enriched in the cytoplasm during apoptosis due to the fact that DNA fragmentation occurs several hours before the plasma membrane breaks down, allowing for accumalation in the cytoplasm.
  • Nucleosomes are not present in the cytoplasmic fraction of cells that are not undergoing apoptosis.
  • An apoptosis assay system may comprise a cell that expresses an LDLR, and that optionally has defective p53 function (e.g. p53 is over-expressed or under-expressed relative to wild-type cells).
  • a test agent can be added to the apoptosis assay system and changes in induction of apoptosis relative to controls where no test agent is added, identify candidate p53 modulating agents.
  • an apoptosis assay may be used as a secondary assay to test a candidate p53 modulating agents that is initially identified using a cell-free assay system.
  • An apoptosis assay may also be used to test whether LDLR function plays a direct role in apoptosis.
  • an apoptosis assay may be performed on cells that over- or under-express LDLR relative to wild type cells. Differences in apoptotic response compared to wild type cells suggests that the LDLR plays a direct role in the apoptotic response. Apoptosis assays are described further in US Pat. No. 6,133,437.
  • Cell proliferation and cell cycle assays may be assayed via bromodeoxyuridine (BRDU) incorporation.
  • BRDU bromodeoxyuridine
  • This assay identifies a cell population undergoing DNA synthesis by incorporation of BRDU into newly-synthesized DNA. Newly-synthesized DNA may then be detected using an anti-BRDU antibody (Hoshino et al, 1986, Int. J. Cancer 38, 369; Campana et al, 1988, J. Immunol. Meth. 107, 79), or by other means.
  • Cell proliferation is also assayed via phospho-histone H3 staining, which identifies a cell population undergoing mitosis by phosphorylation of histone H3.
  • Incorporation can then be measured by standard techniques such as by counting of radioisotope in a scintillation counter (e.g., Beckman LS 3800 Liquid Scintillation Counter).
  • a scintillation counter e.g., Beckman LS 3800 Liquid Scintillation Counter.
  • Another proliferation assay uses the dye Alamar Blue (available from Biosource International), which fluoresces when reduced in living cells and provides an indirect measurement of cell number (Voytik-Harbin SL et al., 1998, In Vitro Cell Dev Biol Anim 34:239-46).
  • MTS assay is based on in vitro cytotoxicity assessment of industrial chemicals, and uses the soluble tetrazolium salt, MTS.
  • MTS assays are commercially available, for example, the Promega CellTiter 96 ® AQueous Non-Radioactive Cell Proliferation Assay (Cat.# G5421).
  • Cell proliferation may also be assayed by colony formation in soft agar (Sambrook et al., Molecular Cloning, Cold Spring Harbor (1989)). For example, cells transformed with LDLR are seeded in soft agar plates, and colonies are measured and counted after two weeks incubation.
  • Cell proliferation may also be assayed by measuring ATP levels as indicator of metabolically active cells.
  • assays are commercially available, for example Cell Titer-GloTM, which is a luminescent homogeneous assay available from Promega. Involvement of a gene in the cell cycle may be assayed by flow cytometry (Gray
  • a cell proliferation or cell cycle assay system may comprise a cell that expresses an LDLR, and that optionally has defective p53 function (e.g. p53 is over- expressed or under-expressed relative to wild-type cells).
  • a test agent can be added to the assay system and changes in cell proliferation or cell cycle relative to controls where no test agent is added, identify candidate p53 modulating agents.
  • the cell proliferation or cell cycle assay may be used as a secondary assay to test a candidate p53 modulating agents that is initially identified using another assay system such as a cell-free assay system.
  • a cell proliferation assay may also be used to test whether LDLR function plays a direct role in cell proliferation or cell cycle.
  • a cell proliferation or cell cycle assay may be performed on cells that over- or under- express LDLR relative to wild type cells. Differences in proliferation or cell cycle compared to wild type cells suggests that the LDLR plays a direct role in cell proliferation or cell cycle.
  • Angiogenesis may be assayed using various human endothelial cell systems, such as umbilical vein, coronary artery, or dermal cells. Suitable assays include Alamar Blue based assays (available from Biosource International) to measure proliferation; migration assays using fluorescent molecules, such as the use of Becton Dickinson Falcon HTS FluoroBlock cell culture inserts to measure migration of cells through membranes in presence or absence of angiogenesis enhancer or suppressors; and tubule formation assays based on the formation of tubular structures by endothelial cells on Matrigel® (Becton Dickinson).
  • Alamar Blue based assays available from Biosource International
  • migration assays using fluorescent molecules such as the use of Becton Dickinson Falcon HTS FluoroBlock cell culture inserts to measure migration of cells through membranes in presence or absence of angiogenesis enhancer or suppressors
  • tubule formation assays based on the formation of tubular structures by endothelial cells on Ma
  • an angiogenesis assay system may comprise a cell that expresses an LDLR, and that optionally has defective p53 function (e.g. p53 is over-expressed or under-expressed relative to wild-type cells).
  • a test agent can be added to the angiogenesis assay system and changes in angiogenesis relative to controls where no test agent is added, identify candidate p53 modulating agents.
  • the angiogenesis assay may be used as a secondary assay to test a candidate p53 modulating agents that is initially identified using another assay system.
  • An angiogenesis assay may also be used to test whether LDLR function plays a direct role in cell proliferation.
  • an angiogenesis assay may be performed on cells that over- or under-express LDLR relative to wild type cells. Differences in angiogenesis compared to wild type cells suggests that the LDLR plays a direct role in angiogenesis.
  • hypoxia inducible factor-1 The alpha subunit of the transcription factor, hypoxia inducible factor-1 (HQF-l), is upregulated in tumor cells following exposure to hypoxia in vitro.
  • HJP-1 stimulates the expression of genes known to be important in tumour cell survival, such as those encoding glyolytic enzymes and VEGF.
  • Induction of such genes by hypoxic conditions may be assayed by growing cells transfected with LDLR in hypoxic conditions (such as with 0.1% 02, 5% CO2, and balance N2, generated in a Napco 7001 incubator (Precision Scientific)) and normoxic conditions, followed by assessment of gene activity or expression by Taqman®.
  • a hypoxic induction assay system may comprise a cell that expresses an LDLR, and that optionally has defective p53 function (e.g. p53 is over-expressed or under- expressed relative to wild-type cells).
  • a test agent can be added to the hypoxic induction assay system and changes in hypoxic response relative to controls where no test agent is added, identify candidate p53 modulating agents.
  • the hypoxic induction assay may be used as a secondary assay to test a candidate p53 modulating agents that is initially identified using another assay system.
  • a hypoxic induction assay may also be used to test whether LDLR function plays a direct role in the hypoxic response.
  • hypoxic induction assay may be performed on cells that over- or under-express LDLR relative to wild type cells. Differences in hypoxic response compared to wild type cells suggests that the LDLR plays a direct role in hypoxic induction.
  • Cell adhesion assays measure adhesion of cells to purified adhesion proteins, or adhesion of cells to each other, in presence or absence of candidate modulating agents.
  • Cell-protein adhesion assays measure the ability of agents to modulate the adhesion of cells to purified proteins. For example, recombinant proteins are produced, diluted to 2.5g mL in PBS, and used to coat the wells of a microtiter plate. The wells used for negative control are not coated. Coated wells are then washed, blocked with 1% BSA, and washed again. Compounds are diluted to 2x final test concentration and added to the blocked, coated wells. Cells are then added to the wells, and the unbound cells are washed off. Retained cells are labeled directly on the plate by adding a membrane-permeable fluorescent dye, such as calcein-AM, and the signal is quantified in a fluorescent microplate reader.
  • a membrane-permeable fluorescent dye such as calcein-AM
  • Cell-cell adhesion assays measure the ability of agents to modulate binding of cell adhesion proteins with their native ligands. These assays use cells that naturally or recombinantly express the adhesion protein of choice.
  • cells expressing the cell adhesion protein are plated in wells of a multiwell plate.
  • Cells expressing the ligand are labeled with a membrane-permeable fluorescent dye, such as BCECF , and allowed to adhere to the monolayers in the presence of candidate agents. Unbound cells are washed off, and bound cells are detected using a fluorescence plate reader.
  • High-throughput cell adhesion assays have also been described.
  • small molecule ligands and peptides are bound to the surface of microscope slides using a microarray spotter, intact cells are then contacted with the slides, and unbound cells are washed off.
  • this assay not only the binding specificity of the peptides and modulators against cell lines are determined, but also the functional cell signaling of attached cells using immunofluorescence techniques in situ on the microchip is measured (Falsey JR et al, Bioconjug Chem. 2001 May-Jun;12(3):346-53).
  • Tubulogenesis assays monitor the ability of cultured cells, generally endothelial cells, to form tubular structures on a matrix substrate, which generally simulates the environment of the extracellular matrix.
  • exemplary substrates include MatrigelTM (Becton Dickinson), an extract of basement membrane proteins containing laminin, collagen JN, and heparin sulfate proteoglycan, which is liquid at 4° C and forms a solid gel at 37° C.
  • Other suitable matrices comprise extracellular components such as collagen, fibronectin, and/or fibrin. Cells are stimulated with a pro-angiogenic stimulant, and their ability to form tubules is detected by imaging.
  • Tubules can generally be detected after an overnight incubation with stimuli, but longer or shorter time frames may also be used.
  • Tube formation assays are well known in the art (e.g., Jones MK et al., 1999, Nature Medicine 5:1418-1423). These assays have traditionally involved stimulation with serum or with the growth factors FGF or VEGF. Serum represents an undefined source of growth factors.
  • the assay is performed with cells cultured in serum free medium, in order to control which process or pathway a candidate agent modulates.
  • different target genes respond differently to stimulation with different pro-angiogenic agents, including inflammatory angiogenic factors such as TNF-alpa.
  • a tubulogenesis assay system comprises testing an LDLR's response to a variety of factors, such as FGF, VEGF, phorbol myristate acetate (PMA), TNF-alpha, ephrin, etc.
  • factors such as FGF, VEGF, phorbol myristate acetate (PMA), TNF-alpha, ephrin, etc.
  • An invasion/migration assay tests the ability of cells to overcome a physical barrier and to migrate towards pro-angiogenic signals.
  • Migration assays are known in the art (e.g., Paik JH et al., 2001, J Biol Chem 276:11830-11837).
  • cultured endothelial cells are seeded onto a matrix-coated porous lamina, with pore sizes generally smaller than typical cell size.
  • the matrix generally simulates the environment of the extracellular matrix, as described above.
  • the lamina is typically a membrane, such as the transwell polycarbonate membrane (Corning Costar Corporation, Cambridge, MA), and is generally part of an upper chamber that is in fluid contact with a lower chamber containing pro-angiogenic stimuli. Migration is generally assayed after an overnight incubation with stimuli, but longer or shorter time frames may also be used. Migration is assessed as the number of cells that crossed the lamina, and may be detected by staining cells with hemotoxylin solution (VWR Scientific, South San Francisco, CA), or by any other method for determining cell number. In another exemplary set up, cells are fluorescentiy labeled and migration is detected using fluorescent readings, for instance using the Falcon HTS FluoroBlok (Becton Dickinson).
  • a preferred assay system for migration/invasion assays comprises testing an LDLR's response to a variety of pro-angiogenic factors, including tumor angiogenic and inflammatory angiogenic agents, and culturing the cells in serum free medium.
  • a sprouting assay is a three-dimensional in vitro angiogenesis assay that uses a cell-number defined spheroid aggregation of endothelial cells ("spheroid"), embedded in a collagen gel-based matrix.
  • the spheroid can serve as a starting point for the sprouting of capillary-like structures by invasion into the extracellular matrix (termed "cell sprouting") and the subsequent formation of complex anastomosing networks (Korff and Augustin, 1999, J Cell Sci 112:3249-58).
  • spheroids are prepared by pipetting 400 human umbilical vein endothelial cells into individual wells of a nonadhesive 96-well plates to allow overnight spheroidal aggregation (Korff and Augustin: J Cell Biol 143: 1341-52, 1998).
  • Spheroids are harvested and seeded in 900 ⁇ l of methocel-collagen solution and pipetted into individual wells of a 24 well plate to allow collagen gel polymerization.
  • Test agents are added after 30 min by pipetting 100 ⁇ l of 10-fold concentrated working dilution of the test substances on top of the gel. Plates are incubated at 37°C for 24h.
  • LDLR-specific antibodies For antibody modulators, appropriate primary assays test is a binding assay that tests the antibody's affinity to and specificity for the LDLR protein. Methods for testing antibody affinity and specificity are well known in the art (Harlow and Lane, 1988, 1999, supra).
  • the enzyme-linked immunosorbant assay (ELIS A) is a preferred method for detecting LDLR-specific antibodies; others include FACS assays, radioimmunoassays, and fluorescent assays.
  • screening assays described for small molecule modulators may also be used to test antibody modulators.
  • primary assays may test the ability of the nucleic acid modulator to inhibit or enhance LDLR gene expression, preferably mRNA expression.
  • expression analysis comprises comparing LDLR expression in like populations of cells (e.g., two pools of cells that endogenously or recombinantly express LDLR) in the presence and absence of the nucleic acid modulator. Methods for analyzing mRNA and protein expression are well known in the art.
  • LDLR mRNA expression may be confirmed in cells treated with the nucleic acid modulator (e.g., Current Protocols in Molecular Biology (1994) Ausubel FM et al, eds., John Wiley & Sons, Inc., chapter 4; Freeman WM et al, Biotechniques (1999) 26:112-125; Kallioniemi OP, Ann Med 2001, 33: 142-147; Blohm DH and Guiseppi-Elie, A Curr Opin Biotechnol 2001, 12:41-47).
  • the nucleic acid modulator e.g., Current Protocols in Molecular Biology (1994) Ausubel FM et al, eds., John Wiley & Sons, Inc., chapter 4; Freeman WM et al, Biotechniques (1999) 26:112-125; Kallioniemi OP, Ann Med 2001, 33: 142-147; Blohm DH and Guiseppi-Elie, A Curr Op
  • Protein expression may also be monitored. Proteins are most commonly detected with specific antibodies or antisera directed against either the LDLR protein or specific peptides. A variety of means including Western blotting, ELISA, or in situ detection, are available (Harlow E and Lane D, 1988 and 1999, supra).
  • screening assays described for small molecule modulators may also be used to test nucleic acid modulators.
  • Secondary assays may be used to further assess the activity of LDLR-modulating agent identified by any of the above methods to confirm that the modulating agent affects LDLR in a manner relevant to the p53 pathway.
  • LDLR-modulating agents encompass candidate clinical compounds or other agents derived from previously identified modulating agent. Secondary assays can also be used to test the activity of a modulating agent on a particular genetic or biochemical pathway or to test the specificity of the modulating agent's interaction with LDLR.
  • Secondary assays generally compare like populations of cells or animals (e.g., two pools of cells or animals that endogenously or recombinantly express LDLR) in the presence and absence of the candidate modulator. In general, such assays test whether treatment of cells or animals with a candidate LDLR-modulating agent results in changes in the p53 pathway in comparison to untreated (or mock- or placebo-treated) cells or animals. Certain assays use "sensitized genetic backgrounds", which, as used herein, describe cells or animals engineered for altered expression of genes in the p53 or interacting pathways.
  • Cell based assays may use a variety of mammalian cell lines known to have defective p53 function (e.g. SAOS-2 osteoblasts, H1299 lung cancer cells, C33A and HT3 cervical cancer cells, HT-29 and DLD-1 colon cancer cells, among others, available from American Type Culture Collection (ATCC), Manassas, VA). Cell based assays may detect endogenous p53 pathway activity or may rely on recombinant expression of p53 pathway components. Any of the aforementioned assays may be used in this cell-based format.
  • Candidate modulators are typically added to the cell media but may also be injected into cells or delivered by any other efficacious means.
  • Models for defective p53 pathway typically use genetically modified animals that have been engineered to mis-express (e.g., over- express or lack expression in) genes involved in the p53 pathway.
  • Assays generally require systemic delivery of the candidate modulators, such as by oral administration, injection, etc.
  • p53 pathway activity is assessed by monitoring neovascularization and angiogenesis.
  • Animal models with defective and normal p53 are used to test the candidate modulator's affect on LDLR in Matrigel® assays.
  • Matrigel® is an extract of basement membrane proteins, and is composed primarily of laminin, collagen IV, and heparin sulfate proteoglycan. It is provided as a sterile liquid at 4° C, but rapidly forms a solid gel at 37° C. Liquid Matrigel® is mixed with various angiogenic agents, such as bFGF and VEGF, or with human tumor cells which over-express the LDLR.
  • mice Female athymic nude mice (Taconic, Germantown, NY) to support an intense vascular response.
  • Mice with Matrigel® pellets may be dosed via oral (PO), intraperitoneal (IP), or intravenous (IV) routes with the candidate modulator. Mice are euthanized 5 - 12 days post-injection, and the Matrigel® pellet is harvested for hemoglobin analysis (Sigma plasma hemoglobin kit). Hemoglobin content of the gel is found to correlate the degree of neovascularization in the gel.
  • the effect of the candidate modulator on LDLR is assessed via tumorigenicity assays.
  • Tumor xenograft assays are known in the art (see, e.g., Ogawa K et al, 2000, Oncogene 19:6043-6052). Xenografts are typically implanted SC into female athymic mice, 6-7 week old, as single cell suspensions either from a pre- existing tumor or from in vitro culture. The tumors which express the LDLR endogenously are injected in the flank, 1 x 10 5 to 1 x 10 7 cells per mouse in a volume of 100 ⁇ L using a 27gauge needle. Mice are then ear tagged and tumors are measured twice weekly.
  • Candidate modulator treatment is initiated on the day the mean tumor weight reaches 100 mg.
  • Candidate modulator is delivered IV, SC, IP, or PO by bolus administration.
  • dosing can be performed multiple times per day.
  • the tumor weight is assessed by measuring perpendicular diameters with a caliper and calculated by multiplying the measurements of diameters in two dimensions.
  • the excised tumors maybe utilized for biomarker identification or further analyses.
  • xenograft tumors are fixed in 4% paraformaldehyde,
  • tumorogenicity is monitored using a hollow fiber assay, which is described in U.S. Pat No. US 5,698,413.
  • the method comprises implanting into a laboratory animal a biocompatible, semi-permeable encapsulation device containing target cells, treating the laboratory animal with a candidate modulating agent, and evaluating the target cells for reaction to the candidate modulator.
  • Implanted cells are generally human cells from a pre-existing tumor or a tumor cell line. After an appropriate period of time, generally around six days, the implanted samples are harvested for evaluation of the candidate modulator.
  • Tumorogenicity and modulator efficacy may be evaluated by assaying the quantity of viable cells present in the macrocapsule, which can be determined by tests known in the art, for example, MTT dye conversion assay, neutral red dye uptake, trypan blue staining, viable cell counts, the number of colonies formed in soft agar, the capacity of the cells to recover and replicate in vitro, etc.
  • a tumorogenicity assay use a transgenic animal, usually a mouse, carrying a dominant oncogene or tumor suppressor gene knockout under the control of tissue specific regulatory sequences; these assays are generally referred to as transgenic tumor assays.
  • tumor development in the transgenic model is well characterized or is controlled.
  • the "RIPl-Tag2" transgene comprising the SV40 large T-antigen oncogene under control of the insulin gene regulatory regions is expressed in pancreatic beta cells and results in islet cell carcinomas (Hanahan D, 1985, Nature 315:115-122; Parangi S et al, 1996, Proc Natl Acad Sci USA 93: 2002-2007; Bergers G et al, 1999, Science 284:808-812).
  • the RIP1-TAG2 mice die by age 14 weeks.
  • Candidate modulators may be administered at a variety of stages, including just prior to the angiogenic switch (e.g., for a model of tumor prevention), during the growth of small tumors (e.g., for a model of intervention), or during the growth of large and/or invasive tumors (e.g., for a model of regression).
  • Tumorogenicity and modulator efficacy can be evaluating life-span extension and/or tumor characteristics, including number of tumors, tumor size, tumor morphology, vessel density, apoptotic index, etc.
  • LDLR-modulating agents are useful in a variety of diagnostic and therapeutic applications where disease or disease prognosis is related to defects in the p53 pathway, such as angiogenic, apoptotic, or cell proliferation disorders.
  • the invention also provides methods for modulating the p53 pathway in a cell, preferably a cell pre-determined to have defective or impaired p53 function (e.g. due to overexpression, underexpression, or misexpression of p53, or due to gene mutations), comprising the step of administering an agent to the cell that specifically modulates LDLR activity.
  • the modulating agent produces a detectable phenotypic change in the cell indicating that the p53 function is restored.
  • the phrase "function is restored", and equivalents, as used herein, means that the desired phenotype is achieved, or is brought closer to normal compared to untreated cells. For example, with restored p53 function, cell proliferation and/or progression through cell cycle may normalize, or be brought closer to normal relative to untreated cells.
  • the invention also provides methods for treating disorders or disease associated with impaired p53 function by administering a therapeutically effective amount of an LDLR -modulating agent that modulates the p53 pathway.
  • the invention further provides methods for modulating LDLR function in a cell, preferably a cell pre-determined to have defective or impaired LDLR function, by administering an LDLR -modulating agent. Additionally, the invention provides a method for treating disorders or disease associated with impaired LDLR function by administering a therapeutically effective amount of an LDLR -modulating agent.
  • Various expression analysis methods can be used to diagnose whether LDLR expression occurs in a particular sample, including Northern blotting, slot blotting, ribonuclease protection, quantitative RT-PCR, and microarray analysis, (e.g., Current Protocols in Molecular Biology (1994) Ausubel FM et al, eds., John Wiley & Sons, Inc., chapter 4; Freeman WM et al, Biotechniques (1999) 26:112-125; Kallioniemi OP, Ann Med 2001, 33:142-147; Blohm and Guiseppi-Elie, Curr Opin Biotechnol 2001, 12:41-47).
  • Tissues having a disease or disorder implicating defective p53 signaling that express an LDLR are identified as amenable to treatment with an LDLR modulating agent.
  • the p53 defective tissue overexpresses an LDLR relative to normal tissue.
  • a Northern blot analysis of mRNA from tumor and normal cell lines, or from tumor and matching normal tissue samples from the same patient, using full or partial LDLR cDNA sequences as probes can determine whether particular tumors express or overexpress LDLR.
  • the TaqMan® is used for quantitative RT- PCR analysis of LDLR expression in cell lines, normal tissues and tumor samples (PE Applied Biosystems).
  • reagents such as the LDLR oligonucleotides, and antibodies directed against an LDLR, as described above for: (1) the detection of the presence of LDLR gene mutations, or the detection of either over- or under-expression of LDLR mRNA relative to the non-disorder state; (2) the detection of either an over- or an under-abundance of LDLR gene product relative to the non-disorder state; and (3) the detection of perturbations or abnormalities in the signal transduction pathway mediated by LDLR.
  • reagents such as the LDLR oligonucleotides, and antibodies directed against an LDLR
  • the invention is drawn to a method for diagnosing a disease or disorder in a patient that is associated with alterations in LDLR expression, the method comprising: a) obtaining a biological sample from the patient; b) contacting the sample with a probe for LDLR expression; c) comparing results from step (b) with a control; and d) determining whether step (c) indicates a likelihood of the disease or disorder.
  • the disease is cancer, most preferably a cancer as shown in TABLE 1.
  • the probe may be either DNA or protein, including an antibody.
  • RNAi of various genes was carried out in worms homozygous for p53 deletion.
  • p53 (-/-) worms have a normal phenotype, but are defective in germline apoptotic response to ionizing radiation as p53 is involved in the DNA damage response.
  • worms were subject to gamma-irradiation, and phenotypes were scored.
  • BLAST analysis (Altschul et al., supra) was employed to identify orthologs of C. elegans modifiers. For example, representative sequences from LDLR, GI# 4758688 (SEQ ID NO: 10), and GI#4507901 (SEQ ID NOs: 11) share 34% and 37% amino acid identity, respectively, with the C. elegans T13C2.6. Various domains, signals, and functional subunits in proteins were analyzed using the PSORT (Nakai K., and Horton P., Trends Biochem Sci, 1999, 24:34-6; Kenta Nakai, Protein sorting signals and prediction of subcellular localization, Adv. Protein Chem.
  • the Low- density lipoprotein receptor domain class a (PFAM 00057) of LDLR from GI# 4758688 (SEQ ID NO: 10) is located at approximately amino acid residues 45 to 83, 84 to 124, 125 to 165, 167 to 203, 204 to 247, 257 to 296, 297 to 335
  • Low-density lipoprotein receptor domain class b (PFAM 00058) of the same protein is located at approximately amino acid residues 462 to 507, 509 to 550, 552 to 594, 596 to 639, 640 to 680.
  • Fluorescently-labeled LDLR peptide/substrate are added to each well of a 96- well microtiter plate, along with a test agent in a test buffer (10 mM HEPES, 10 mM NaCl, 6 mM magnesium chloride, pH 7.6). Changes in fluorescence polarization, determined by using a Fluorolite FPM-2 Fluorescence Polarization Microtiter System (Dynatech Laboratories, Inc), relative to control values indicates the test compound is a candidate modifier of LDLR activity.
  • 33 P-labeled LDLR peptide is added in an assay buffer (100 mM KC1, 20 mM HEPES pH 7.6, 1 mM MgCl 2 , 1% glycerol, 0.5% NP-40, 50 mM beta-mercaptoethanol, 1 mg/ml BSA, cocktail of protease inhibitors) along with a test agent to the wells of a Neutralite-avidin coated assay plate and incubated at 25°C for 1 hour. Biotinylated substrate is then added to each well and incubated for 1 hour. Reactions are stopped by washing with PBS, and counted in a scintillation counter. Test agents that cause a difference in activity relative to control without test agent are identified as candidate p53 modulating agents.
  • the cell lysate is incubated with 25 ⁇ l of M2 beads (Sigma) for 2 h at 4 °C with gentle rocking. After extensive washing with lysis buffer, proteins bound to the beads are solubilized by boiling in SDS sample buffer, fractionated by SDS-polyacrylamide gel electrophoresis, transferred to polyvinylidene difluoride membrane and blotted with the indicated antibodies. The reactive bands are visualized with horseradish peroxidase coupled to the appropriate secondary antibodies and the enhanced chemiluminescence (ECL) Western blotting detection system (Amersham Pharmacia Biotech).
  • ECL enhanced chemiluminescence
  • TaqMan analysis was used to assess expression levels of the disclosed genes in various samples.
  • Primers for expression analysis using TaqMan assay were prepared according to the TaqMan protocols, and the following criteria: a) primer pairs were designed to span introns to eliminate genomic contamination, and b) each primer pair produced only one product. Expression analysis was performed using a 7900HT instrument.
  • Taqman reactions were carried out following manufacturer's protocols, in 25 ⁇ l total volume for 96-well plates and 10 ⁇ l total volume for 384-well plates, using 300nM primer and 250 nM probe, and approximately 25ng of cDNA.
  • the standard curve for result analysis was prepared using a universal pool of human cDNA samples, which is a mixture of cDNAs from a wide variety of tissues so that the chance that a target will be present in appreciable amounts is good.
  • the raw data were normalized using 18S rRNA (universally expressed in all tissues and cells).
  • tumor tissue samples were compared with matched normal tissues from the same patient.
  • a gene was considered overexpressed in a tumor when the level of expression of the gene was 2 fold or higher in the tumor compared with its matched normal sample.
  • a universal pool of cDNA samples was used instead.
  • a gene was considered overexpressed in a tumor sample when the difference of expression levels between a tumor sample and the average of all normal samples from the same tissue type was greater than 2 times the standard deviation of all normal samples (i.e., Tumor - average(all normal samples) > 2 x STDEV(all normal samples) ).
  • Results are shown in Table 1. Number of pairs of tumor samples and matched normal tissue from the same patient are shown for each tumor type. Percentage of the samples with at least two-fold overexpression for each tumor type is provided.
  • a modulator identified by an assay described herein can be further validated for therapeutic effect by administration to a tumor in which the gene is overexpressed. A decrease in tumor growth confirms therapeutic utility of the modulator.
  • the likelihood that the patient will respond to treatment can be diagnosed by obtaining a tumor sample from the patient, and assaying for expression of the gene targeted by the modulator.
  • the expression data for the gene(s) can also be used as a diagnostic marker for disease progression.
  • the assay can be performed by expression analysis as described above, by antibody directed to the gene target, or by any other available detection method.

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Abstract

Selon l'invention, les gènes du récepteur de la lipoprotéine basse densité (LDLR) humain sont identifiés en tant que modulateurs de la voie p53, et ainsi les cibles thérapeutiques pour les troubles sont associées à un dysfonctionnement de la p53. L'invention concerne des procédés d'identification des modulateurs de p53, comprenant le criblage des agents qui modulent l'activité du LDLR.
PCT/US2003/028902 2002-09-16 2003-09-15 Ldlr utilise en tant que modificateur de la voie p53 et procedes d'utilisation associes WO2004024881A2 (fr)

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US20020065229A1 (en) * 2000-11-29 2002-05-30 Davis Ashley Stuart Anti-S-phase tubulin ligands
US6407062B1 (en) * 1995-09-27 2002-06-18 St. Jude Children's Research Hospital ARF-P19, a novel regulator of the mammalian cell cycle

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6407062B1 (en) * 1995-09-27 2002-06-18 St. Jude Children's Research Hospital ARF-P19, a novel regulator of the mammalian cell cycle
US20020065229A1 (en) * 2000-11-29 2002-05-30 Davis Ashley Stuart Anti-S-phase tubulin ligands

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JACKSON-GRUSBY ET AL: 'Loss of genomic methylation cases p53-dependent apoptosis and epigenetic deregulation' NATURE GENETICS vol. 27, January 2001, pages 31 - 39, XP002975926 *

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