A 250-kilodalton cellular protein is induced by progestins in two human breast cancer cell lines MCF7 and T47D.
We have studied the effect of R5020, a synthetic progestin, on the biosynthesis of cellular proteins extracted from the MCF7 and T47D human breast cancer cells, using gel electrophoresis. R5020 stimulates the synthesis, as measured after [35S]-methionine labelling, and the accumulation, as shown by silver staining, of a protein of molecular weight approximately equal to 250,000. The increase of the labelled 250-kilodalton protein was rapid (3 hours) and after 3 days this protein represented approximately equal to 6% of the total cellular proteins (approximately equal to 1 microgram/150,000 cells). The induction of the 250-kilodalton protein was obtained by physiologically active concentrations of several progestins and high concentrations of 5 alpha-dihydrotestosterone but not by estradiol or dexamethasone. It was inhibited by R486 , a progestin antagonist, but not by flutamide, an androgen antagonist. These results indicate a mediation by the progesterone receptor. The 250-kilodalton protein appears to be an excellent probe to study in cell culture the mechanism of action of progestin on human cells.
D001943:Breast Neoplasms / Q000378:metabolism*; D002460:Cell Line; D055598:Chemical Phenomena; D002621:Chemistry; D003907:Dexamethasone / Q000494:pharmacology; D013196:Dihydrotestosterone / Q000494:pharmacology; D004586:Electrophoresis / Q000379:methods; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006801:Humans; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D011372:Progestins / Q000494:pharmacology*; D011397:Promegestone / Q000494:pharmacology
D009363:Neoplasm Proteins; D011372:Progestins; D013196:Dihydrotestosterone; D004958:Estradiol; D003907:Dexamethasone; D011397:Promegestone