title: Genistein modulates the effects of parathyroid hormone in human osteoblastic SaOS-2 cells.
abstract: Genistein and parathyroid hormone (PTH) are anabolic agents that stimulate bone formation through their direct actions in osteoblastic cells. In the present study, we aimed to determine whether genistein modulates the actions of PTH in human osteoblastic SaOS-2 cells in an oestrogen-depleted condition. The present results showed that genistein (10(-8) to 10(-6) m) induced alkaline phosphatase (ALP) activity and osteoprotegrin (OPG) expression in SaOS-2 cells in a dose-dependent manner. These effects could be completely abolished by co-treatment with oestrogen antagonist ICI 182780 (7alpha-[9-[(4,4,5,5,5-pentafluoropentyl)sulfonyl]nonyl]-estra-1,3,5(10)-triene-3,17beta-diol). Genistein (at 1 microM) could stimulate the mRNA expression of receptor activator of NF-kappaB ligand (RANKL). As OPG and RANKL are known to modulate osteoclastogenesis, the ability of genistein to modulate OPG and RANKL expression in SaOS-2 cells suggested that it might modulate osteoclastogenesis through its direct actions on osteoblastic cells. PTH (at 10 nM) stimulated ALP activity, induced RANKL mRNA expression and suppressed OPG mRNA expression in SaOS-2 cells, confirming its bi-directional effects on osteoblastic cells. Pre-treatment of SaOS-2 cells with genistein and oestrogen not only enhanced PTH-induced ALP activity, but also attenuated PTH up regulation of RANKL mRNA expression and PTH down regulation of OPG mRNA expression. Taken together, the present study provides the first evidence that genistein could modulate the actions of PTH in human osteoblastic SaOS-2 cells in an oestrogen-depleted condition.
authors.affiliation: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China.
authors.forename: Wen-Fang
authors.initials: WF
authors.lastname: Chen
authors.forename: Man-Sau
authors.initials: MS
authors.lastname: Wong
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D000077267:Fulvestrant; D015870:Gene Expression / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D053244:Osteoprotegerin; D010281:Parathyroid Hormone / Q000494:pharmacology*; D053245:RANK Ligand; D012333:RNA, Messenger / Q000032:analysis; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013268:Stimulation, Chemical
chemical_list: D002352:Carrier Proteins; D004965:Estrogen Antagonists; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; C470125:PTH protein, human; D010281:Parathyroid Hormone; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D000077267:Fulvestrant; D004958:Estradiol; D019833:Genistein; D000469:Alkaline Phosphatase