Persistent induction of cyclooxygenase in p60v-src-transformed 3T3 fibroblasts.
A BALB/c 3T3 cell line infected with the temperature-sensitive Rous sarcoma virus strain LA90 has been used to investigate early, p60v-src-dependent changes in gene expression (protein synthesis). Giant two-dimensional electrophoresis, which can resolve greater than 3000 polypeptides from [35S]methionine-labeled cell lysates, was used to detect the induction of a p72-74 (72-74 kDa) doublet (pI 7.5) after activation of p60v-src at 35 degrees C. Antiserum against cyclooxygenase (prostaglandin synthase or prostaglandin endoperoxide synthase) specifically immunoprecipitated the p72-74 doublet. The p72-74 doublet was also induced by platelet-derived growth factor and by phorbol 12-myristate 13-acetate and was elevated in an NIH 3T3 cell line transformed by wild-type src. Activation of p60v-src caused a persistent increase in p72-74, whereas the effect of the growth factor was transient. These dissimilar kinetics of induction were paralleled by changes in cyclooxygenase activity. Down-regulation of protein kinase C inhibited subsequent induction of cyclooxygenase by phorbol myristate acetate but did not block induction by p60v-src. The glucocorticoid agonist dexamethasone inhibited induction of cyclooxygenase by p60v-src. Although induction of this enzyme may not be directly involved in transformation, the data support the view that oncogenic transformation may result, not from expression of transformation-specific genes, but from persistent changes in the expression of genes normally induced only transiently during passage from the G0 stage of the cell cycle.
Han
J W
JW
Department of Biophysics, University of Rochester Medical Center, NY 14642.
Sadowski
H
H
Young
D A
DA
Macara
I G
IG
D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D004790:Enzyme Induction; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D051379:Mice; D009154:Mutation; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis*; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D013696:Temperature; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D010982:Platelet-Derived Growth Factor; D003907:Dexamethasone; D008715:Methionine; D011451:Prostaglandin-Endoperoxide Synthases; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src); D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate