title: Inhibition of human mammary carcinoma cell proliferation by retinoids and intracellular cAMP-elevating compounds.
abstract: Retinoids and cAMP-elevating agents markedly inhibited the proliferation of human mammary tumor cells. Their response has been previously correlated with the presence of estrogen receptor (ER) positivity. MDA-MB-231 cells were ER negative and insensitive to the antiproliferative effects of retinoids. However, their growth was markedly inhibited by agents that elevated intracellular cAMP levels, i.e., 8-bromo-cAMP, cholera toxin (CT), forskolin, and the phosphodiesterase inhibitor papaverine. The CT and forskolin inhibition of the ER-positive cells (MCF-7) was associated with an elevation of adenylate cyclase activity and intracellular cAMP levels; however, similar elevations in intracellular cAMP levels were not observed following CT or forskolin inhibition of MDA-MB-231 cells but only following the addition of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine.
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D006801:Humans; D010208:Papaverine / Q000494:pharmacology; D012176:Retinoids / Q000627:therapeutic use*; D013268:Stimulation, Chemical
chemical_list: D012176:Retinoids; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D002772:Cholera Toxin; D010208:Papaverine; D000242:Cyclic AMP