title: The role of progesterone metabolites in breast cancer: potential for new diagnostics and therapeutics.
abstract: Proliferative changes in the normal breast are known to be controlled by female sex steroids. However, only a portion of all breast cancer patients respond to current estrogen based endocrine therapy, and with continued treatment nearly all will become unresponsive and experience relapse. Therefore, ultimately for the majority of breast carcinomas, explanations and treatments based on estrogen are inadequate. Recent observations indicate that 5alpha-pregnane and 4-pregnene progesterone metabolites may serve as regulators of estrogen-responsive as well as unresponsive human breast cancers. The conversion of progesterone to the 5alpha-pregnanes is increased while conversion to the 4-pregnenes is decreased in breast carcinoma tissue, as a result of changes in progesterone metabolizing 5alpha-reductase, 3alpha-hydroxysteroid oxidoreductase (3alpha-HSO) and 20alpha-HSO activities and gene expression. The 5alpha-pregnane, 5alpha-pregnane-3,20-dione (5alphaP) stimulates, whereas the 4-pregnene, 3alpha-hydroxy-4-pregnen-20-one (3alphaHP), inhibits cell proliferation and detachment, by modulation of cytoskeletal and adhesion plaque molecules via the MAP kinase pathway and involving separate and specific plasma membrane-based receptors. The promotion of breast cancer appears to be related to changes in in situ concentrations of cancer-inhibiting and cancer-promoting progesterone metabolites. New diagnostic and therapeutic possibilities for breast cancer are suggested.
authors.affiliation: Department of Biology, Hormonal Regulatory Mechanisms Laboratory, University of Western Ontario, London, Ont., Canada N6A 5B7. jwiebe@uwo.ca
authors.forename: J P
authors.initials: JP
authors.lastname: Wiebe
authors.forename: M J
authors.initials: MJ
authors.lastname: Lewis
authors.forename: V
authors.initials: V
authors.lastname: Cialacu
authors.forename: K J
authors.initials: KJ
authors.lastname: Pawlak
authors.forename: G
authors.initials: G
authors.lastname: Zhang
mesh_terms: D043607:20-alpha-Hydroxysteroid Dehydrogenase / Q000235:genetics / Q000378:metabolism; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific) / Q000235:genetics / Q000378:metabolism; D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D002273:Carcinogens / Q000378:metabolism / Q000633:toxicity; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D042944:Cholestenone 5 alpha-Reductase / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D020935:MAP Kinase Signaling System; D009376:Neoplasms, Hormone-Dependent / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D011278:Pregnanes / Q000378:metabolism / Q000633:toxicity; D011283:Pregnenes / Q000378:metabolism / Q000494:pharmacology; D011374:Progesterone / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002273:Carcinogens; D011278:Pregnanes; D011283:Pregnenes; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011374:Progesterone; D043607:20-alpha-Hydroxysteroid Dehydrogenase; D045002:3-alpha-Hydroxysteroid Dehydrogenase (B-Specific); D042944:Cholestenone 5 alpha-Reductase