The long-range goal is to understand the mechanisms by which carcinogens induce mutations in human cells and the role such mutations play in the neoplastic transformation of human cells in culture and in human carcinogenesis. Mutations in the p53 gene are very frequently found in a variety of types of human tumors, including bone and soft tissue sarcomas, and are distributed non-randomly in characteristic """"""""hot spots"""""""" in evolutionarily conserved regions of the gene. Such mutations are known to predispose cells to malignancy. We are interested in factors that determine the kinds and distribution of these mutations (spectrum). we have a quantitative system for carcinogen-induced transformation of a near- diploid, karyotypically stable human fibroblast cell strain that yields malignantly-transformed cells with p53 mutations. We will use it to determine the relationship between the frequency and spectrum of mutations induced in the coding region of the p53 gene of the cell strains and the spectrum of carcinogen adducts initially formed in the gene, or still remaining unrepaired in the gene at the time S-phase replication occurs. LM-PCR will be used to determine the spectrum of carcinogen adducts at the sequence level. We will determine the relationship between these carcinogen-induced mutations in the p53 gene of the cells, loss of p53 transactivating function, and the ability of the focus-derived cell strains to form tumors in athymic mice. The spectrum of p53 mutations induced in the cell strains that are malignant will be compared to those reported for human tumors. We will analyze the ability of selected p53 mutated alleles, generated in this study and assayed for the status of transactivating function of the protein, to exert their transforming effect in the presence or absence of a wild type allele. (Evidence shows that certain p53 mutations allow the mutant p53 protein to sequester the wild type protein, but that others can stabilize the p53 protein only when there is not wild type allele.) Selected cell strains from the proposed study will be transfected with these alleles carried on an expression vector with a modulatable promoter. The ability of a transfected wild type allele to suppress transformation of MSU-1.1 cells to focus formation and tumorigenicity will be similarly tested.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
2R01CA021253-17A2
Application #
2086938
Study Section
Chemical Pathology Study Section (CPA)
Project Start
1988-07-01
Project End
1997-06-30
Budget Start
1994-07-15
Budget End
1995-06-30
Support Year
17
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Michigan State University
Department
Internal Medicine/Medicine
Type
Schools of Osteopathy
DUNS #
193247145
City
East Lansing
State
MI
Country
United States
Zip Code
48824
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Wei, D; Maher, V M; McCormick, J J (1995) Site-specific rates of excision repair of benzo[a]pyrene diol epoxide adducts in the hypoxanthine phosphoribosyltransferase gene of human fibroblasts: correlation with mutation spectra. Proc Natl Acad Sci U S A 92:2204-8
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