Bombesin induces c-fos and c-myc expression in quiescent Swiss 3T3 cells. Comparative study with other mitogens.
We have studied the effect of the potent mitogen bombesin on the expression of c-fos and c-myc genes in quiescent mouse fibroblasts. We have demonstrated that bombesin rapidly induces a transient expression of c-fos mRNA followed by a more protracted elevation in c-myc mRNA levels. The intensity of the induction of expression of both proto-oncogenes depended on the dose of bombesin used. Prolonged treatment of the cells with TPA, which causes a selective decrease in protein kinase C activity, partially inhibited the induction of c-fos and c-myc gene expression by bombesin, similar to what has been observed with PDGF. However, a dramatic inhibition of the mitogenic response to bombesin--but not to PDGF--was found in TPA-treated cells. In contrast, TPA-treated cells showed an increased response to EGF with regard to proto-oncogene expression. The role of protein kinase C and Ca2+-dependent pathways in proto-oncogene induction by bombesin is discussed.
D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D051379:Mice; D008934:Mitogens / Q000494:pharmacology*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011519:Proto-Oncogenes / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D008934:Mitogens; D010982:Platelet-Derived Growth Factor; D012333:RNA, Messenger; D004815:Epidermal Growth Factor; D013755:Tetradecanoylphorbol Acetate; D001839:Bombesin