Consistent oncogene methylation changes in epithelial cells chemically transformed in vitro.
We have examined the restriction digest patterns of CCGG sequences in Kiras, Ha-ras, and c-myc oncogenes in rat tracheal epithelial cells transformed in vitro by 7,12-dimethylbenz(a)anthracene, benzo(a)pyrene/12-O-tetradecanoylphorbol-13-acetate (TPA), or TPA alone. Oncogenes c-myc and Ha-ras in transformed cell lines, compared to normal rat tracheal epithelial cells and untreated primary cultures, had altered Hpa II restriction patterns as demonstrated by hybridizing bands of different molecular weight, or loss of bands. Ki-ras was hypermethylated in all cell derivations, including normal cells. These molecular alterations have not previously been reported for epithelial cells transformed in vitro by polycyclic hydrocarbons and tumor promoters, and suggest common mechanisms of action for agents with diverse molecular targets.
Mass
M J
MJ
Genetic Toxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711.
Schorschinsky
N S
NS
Lasley
J A
JA
Beeman
D K
DK
Austin
S J
SJ
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology*; D000818:Animals; D001483:Base Sequence; D001564:Benzo(a)pyrene / Q000494:pharmacology*; D015139:Blotting, Southern; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D004247:DNA / Q000187:drug effects / Q000235:genetics; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects; D011905:Genes, ras / Q000187:drug effects*; D008297:Male; D008745:Methylation; D011519:Proto-Oncogenes / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344; D015183:Restriction Mapping; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014132:Trachea
D001564:Benzo(a)pyrene; D015127:9,10-Dimethyl-1,2-benzanthracene; D004247:DNA; D013755:Tetradecanoylphorbol Acetate