Reduced induction of c-fos but not of c-myc expressions in a nontumorigenic revertant R1 of Ej-ras-transformed NIH/3T3 cells treated with 12-O-tetradecanoylphorbol-13-acetate (TPA).
It has been reported that both c-fos and c-myc mRNAs are induced in NIH/3T3 cells after 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment. We have studied the effect of TPA on the expression of c-fos and c-myc in EJ-ras-transformed NIH/3T3 and its nontumorigenic flat revertant R1 cells. Although TPA treatment induces c-myc mRNA, as in the case of NIH/3T3 cells, the induced level of c-fos mRNA is greatly reduced not only in slow-growing EJ-ras-transformed NIH/3T3 but also in quiescent R1 cells. In addition, serum-induced c-fos expression is also reduced in EJ-ras-transformed NIH/3T3 and R1 cells. These observations suggest that the pathway from TPA to c-fos gene is different from that to c-myc gene and that the former pathway is down-regulated in association not with the transformed phenotype, but with EJ-ras expression, and it is possible that this reduced induction of c-fos is not specific to TPA.
Suzuki
H
H
Laboratory of Molecular Genetics, Hokkaido University School of Medicine, Sapporo, Japan.
Fujita
H
H
Ogiso
Y
Y
Oda
A
A
Kuzumaki
N
N
Uchino
J
J
D000818:Animals; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000473:pathology; D005347:Fibroblasts / Q000378:metabolism* / Q000473:pathology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D051379:Mice; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects*
D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D013755:Tetradecanoylphorbol Acetate