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CONSISTENT ONCOGENE METHYLATION CHANGES IN EPITHELIAL CELLS CHEMICALLY TRANSFORMED IN VITRO
Citation:
Mass, M., N. Schorschinsky, J. Lasley, D. Beeman, AND S. Austin. CONSISTENT ONCOGENE METHYLATION CHANGES IN EPITHELIAL CELLS CHEMICALLY TRANSFORMED IN VITRO. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-89/383.
Description:
Many cancers occurring in humans and In animals are accompanied by alterations in oncogene DNA secluences, amplification, or changes in expression (1,2). In some cases the changes are quite specific and prevalent such as in Burkitts's lymphoma, pancreatic, and thyroid carcinoma (3-5). tudies of human lung cancers have revealed heterogeneous activated oncogenes in varied proportions of tumors (2,6-3) and prompted us to consider that genetic events present in established tumors may not be reflective of those occurring early in precursor initiated cells. e and others have utilized the RTE cell transformation system (9-12) as a surrogate to study early molecular events in respiratory carcinogenesis. TE cells transformed by chemical carcinogens in vitro (13,14) and early preneoplastIc lesions in vivo (15) have been examined. owever, RTE cells transformed by polycyclic hydrocarbons appear to sustain no consistent changes in Ha-ras, c-myc, and Ki-ras oncogenes by RFLP analysis, and DNA isolated from these cells is devoid of transfectable transforming genes in NIH3T3 cells (14). n the present study we have determined that rat tracheal epithelial cells by diverse carcinogens share common changes in DNA methylation patterns in Ha-ras and c-myc oncogenes as determined by Hpa Il digestion. his is the first report of a common molecular alteration for these cells.