Osteogenic Activities of Genistein Derivatives were Influenced by the Presence of Prenyl Group at Ring A

Zhang, Yan,Li, Xiao-Li,Yao, Xin-Sheng,Wong, Man-Sau 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.12

Our recent report indicated that the crude extract from stem bark of Erythrina variegata L. (Leguminosae) (EV) exerted beneficial effects against osteoporosis induced by estrogen deficiency in vivo. Followup phytochemical study has isolated genistein-derivatives mainly in the form of prenylgenistein from this extract, including 6-prenylgenistein, 8-prenylgenistein, and 6, 8-diprenylgenistein. The present study was performed to investigate the structure-function relationship of these compounds on osteoblastic proliferation, differentiation and mineralization in UMR 106 cells. Our results showed that genistein did not stimulate cell growth while 8-prenylgenistein promoted cell growth significantly by 10$\sim$23%. In contrast, the treatment by 6-prenylgenistein for 48 h reduced UMR 106 cell proliferation when compared to cells treated with genistein. The proliferation of 6,8-diprenylgenistein-treated cells was greater than those treated by 6-prenylgenistein at all testing concentrations. For ALP activity, significant increase was found in cells treated by either 8-prenylgenistein or 6,8-diprenylgenistein for 48 h at the concentration of $10^{-10}M$. In mineralization study, the content of Ca and P in extracellular matrix were significantly increased in 8-prenylgenistein treated cells. The results showed that genistein derivatives isolated from EV demonstrated stimulatory effects on osteogenesis in UMR 106 cells. Based on the study of structure-activity relationship, it appears that prenylation at C-8, but not at C-6, could increase the bone-protective effect of genistein.

Osteogenic Activities of Genistein Derivatives were Influenced by the Presence of Prenyl Group at Ring A

Yan Zhang,Xiao-Li Li,Xin-Sheng Yao,Man-Sau Wong 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.12

Our recent report indicated that the crude extract from stem bark of Erythrina variegata L. (Leguminosae) (EV) exerted beneficial effects against osteoporosis induced by estrogen deficiency in vivo. Followup phytochemical study has isolated genistein-derivatives mainly in the form of prenylgenistein from this extract, including 6-prenylgenistein, 8-prenylgenistein, and 6, 8-diprenylgenistein. The present study was performed to investigate the structure-function relationship of these compounds on osteoblastic proliferation, differentiation and mineralization in UMR 106 cells. Our results showed that genistein did not stimulate cell growth while 8-prenylgenistein promoted cell growth significantly by 10~23%. In contrast, the treatment by 6-prenylgenistein for 48 h reduced UMR 106 cell proliferation when compared to cells treated with genistein. The proliferation of 6,8-diprenylgenistein-treated cells was greater than those treated by 6-prenylgenistein at all testing concentrations. For ALP activity, significant increase was found in cells treated by either 8-prenylgenistein or 6,8-diprenylgenistein for 48 h at the concentration of 10-10 M. In mineralization study, the content of Ca and P in extracellular matrix were significantly increased in 8-prenylgenistein treated cells. The results showed that genistein derivativesisolated from EV demonstrated stimulatory effects on osteogenesis in UMR 106 cells. Based on thestudy of structure-activity relationship, it appears that prenylation at C-8, but not at C-6, could increasethe bone-protective effect of genistein.

Ginsenoside Rg1 activates ligand-independent estrogenic effects via rapid estrogen receptor signaling pathway

Quan-Gui Gao,Li-Ping Zhou,Vien Hoi-Yi Lee,Hoi-Yi Chan,Cornelia Wing-Yin Man,Man-Sau Wong 고려인삼학회 2019 Journal of Ginseng Research Vol.43 No.4

Background: Ginsenoside Rg1 was shown to exert ligand-independent activation of estrogen receptor(ER) via mitogen-activated protein kinaseemediated pathway. Our study aimed to delineate themechanisms by which Rg1 activates the rapid ER signaling pathways. Methods: ER-positive human breast cancer MCF-7 cells and ER-negative human embryonic kidneyHEK293 cells were treated with Rg1 (10 12M, 10 8M), 17ß-estradiol (10 8M), or vehicle. Immunoprecipitationwas conducted to investigate the interactions between signaling protein and ER in MCF-7 cells. To determine the roles of these signaling proteins in the actions of Rg1, small interfering RNA or theirinhibitors were applied. Results: Rg1 rapidly induced ERa translocation to plasma membrane via caveolin-1 and the formation ofsignaling complex involving linker protein (Shc), insulin-like growth factor-I receptor, modulator ofnongenomic activity of ER (MNAR), ERa, and cellular nonreceptor tyrosine kinase (c-Src) in MCF-7 cells. The induction of extracellular signal-regulated protein kinase and mitogen-activated protein kinase kinase(MEK) phosphorylation in MCF-7 cells by Rg1 was suppressed by cotreatment with small interferingRNA against these signaling proteins. The stimulatory effects of Rg1 on MEK phosphorylation in thesecells were suppressed by both PP2 (Src kinase inhibitor) and AG1478 [epidermal growth factor receptor(EGFR) inhibitor]. In addition, Rg1-induced estrogenic activities, EGFR and MEK phosphorylation in MCF-7 cells were abolished by cotreatment with G15 (G protein-coupled estrogen receptor-1 antagonist). Theincrease in intracellular cyclic AMP accumulation, but not Ca mobilization, in MCF-7 cells by Rg1 could beabolished by G15. Conclusion: Ginsenoside Rg1 exerted estrogenic actions by rapidly inducing the formation of ER containingsignalosome in MCF-7 cells. Additionally, Rg1 could activate EGFR and c-Src ER-independentlyand exert estrogenic effects via rapid activation of membrane-associated ER and G protein-coupled estrogenreceptor.

Ginsenoside Rg1 activates ligand-independent estrogenic effects via rapid estrogen receptor signaling pathway

Gao, Quan-Gui,Zhou, Li-Ping,Lee, Vien Hoi-Yi,Chan, Hoi-Yi,Man, Cornelia Wing-Yin,Wong, Man-Sau The Korean Society of Ginseng 2019 Journal of Ginseng Research Vol.43 No.4

Background: Ginsenoside Rg1 was shown to exert ligand-independent activation of estrogen receptor (ER) via mitogen-activated protein kinase-mediated pathway. Our study aimed to delineate the mechanisms by which Rg1 activates the rapid ER signaling pathways. Methods: ER-positive human breast cancer MCF-7 cells and ER-negative human embryonic kidney HEK293 cells were treated with Rg1 ($10^{-12}M$, $10^{-8}M$), $17{\beta}$-estradiol ($10^{-8}M$), or vehicle. Immunoprecipitation was conducted to investigate the interactions between signaling protein and ER in MCF-7 cells. To determine the roles of these signaling proteins in the actions of Rg1, small interfering RNA or their inhibitors were applied. Results: Rg1 rapidly induced $ER{\alpha}$ translocation to plasma membrane via caveolin-1 and the formation of signaling complex involving linker protein (Shc), insulin-like growth factor-I receptor, modulator of nongenomic activity of ER (MNAR), $ER{\alpha}$, and cellular nonreceptor tyrosine kinase (c-Src) in MCF-7 cells. The induction of extracellular signal-regulated protein kinase and mitogen-activated protein kinase kinase (MEK) phosphorylation in MCF-7 cells by Rg1 was suppressed by cotreatment with small interfering RNA against these signaling proteins. The stimulatory effects of Rg1 on MEK phosphorylation in these cells were suppressed by both PP2 (Src kinase inhibitor) and AG1478 [epidermal growth factor receptor (EGFR) inhibitor]. In addition, Rg1-induced estrogenic activities, EGFR and MEK phosphorylation in MCF-7 cells were abolished by cotreatment with G15 (G protein-coupled estrogen receptor-1 antagonist). The increase in intracellular cyclic AMP accumulation, but not Ca mobilization, in MCF-7 cells by Rg1 could be abolished by G15. Conclusion: Ginsenoside Rg1 exerted estrogenic actions by rapidly inducing the formation of ER containing signalosome in MCF-7 cells. Additionally, Rg1 could activate EGFR and c-Src ER-independently and exert estrogenic effects via rapid activation of membrane-associated ER and G protein-coupled estrogen receptor.