[Modifications of gene expression by tumor promoters].
The modifications of gene expression by tumor promoters were analyzed in vitro and in vivo. The results of slot blot hybridizations showed that tumor promoter TPA induced c-fos and c-myc expressions in mouse fibroblast cell line BALB/3T3 and rat liver, decreased the levels of Rb RNA in BALB/3T3 cell line and of alpha 1-I3 RNA in rat liver. It was also demonstrated that tumor promoter phenobarbital influenced c-fos and c-myc expressions and decreased alpha 1I3 mRNA level in rat liver during a long term experiment. Phenobarbital was found to have no effect on c-fos and c-myc expressions in rat liver during a short experiment. Tumor promoters induced the expressions of c-fos and c-myc which were positively-related to cancer formation and inhibited the expressions of Rb and alpha 1-I3 which were negatively-related to cancer formation. This implied that tumor promotion played an important role in cancer development and tumor promoters exerted their effects selectively according to the attributes of different genes.
Zhang
C
C
Cancer Institute, CAMS, Beijing.
Zhao
Q
Q
Guo
S
S
Zhao
M
M
Cheng
S
S
D016475:3T3 Cells / Q000187:drug effects / Q000378:metabolism; D000209:Acute-Phase Proteins; D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D003436:Croton Oil / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D016161:Genes, Retinoblastoma; D016762:Genes, fos; D016259:Genes, myc; D008099:Liver / Q000166:cytology / Q000378:metabolism; D008297:Male; D051379:Mice; D010634:Phenobarbital / Q000494:pharmacology; D011480:Protease Inhibitors / Q000378:metabolism; D012313:RNA / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013755:Tetradecanoylphorbol Acetate / Q000633:toxicity*
D000209:Acute-Phase Proteins; D002273:Carcinogens; D011480:Protease Inhibitors; C017894:alpha 1-inhibitor 3; D012313:RNA; D003436:Croton Oil; D013755:Tetradecanoylphorbol Acetate; D010634:Phenobarbital