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Formononetin is one of the main active components of traditional Chinese medicine red clover (Trifolium pratense L). Prior studies have demonstrated that formononetin is a typical phytoestrogen and exhibits an estrogen-like effect that protects the cardiovascular system with minimal side effects. In this study, we further investigated the role of formononetin in human umbilical vein endothelial cells (HUVECs) and its potential molecular mechanisms. We founded that formononetin promotes proliferation and migration of HUVECs as assessed by the MTT and wound healing assays. Meanwhile, insulin-like growth factor 1 (IGF-1) and intercellular adhesion molecule 1 (ICAM-1) protein levels were increased in a dose-dependent manner. Our findings illustrated that formononetin exhibits a protective effect on HUVECs, and the molecular mechanisms may correlate with IGF-1R and ICAM-1, as well as upregulation of vascular endothelial growth factor (VEGF) and activation of extracellular signal-regulated kinase (ERK)., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

For postmenopausal cardiovascular disease, long-term estrogen therapy may increase the risk of breast cancer. To reduce this risk, estrogen may be replaced with the phytoestrogen formononetin, but how formononetin acts on vascular endothelial cells (ECs) and breast cancer cells is unclear. Here, we show that low concentrations of formononetin induced proliferation and inhibited apoptosis more strongly in cultured human umbilical vein endothelial cells (HUVECs) than in breast cancer cells expressing estrogen receptor α (ERα) (MCF-7, BT474) or not (MDA-MB-231), and that this differential stimulation was associated with miR-375 up-regulation in HUVECs. For the first time, we demonstrate the presence of a feedback loop involving miR-375, ras dexamethasone-induced 1 (RASD1), and ERα in normal HUVECs, and we show that formononetin stimulated this feedback loop in HUVECs but not in MCF-7 or BT474 cells. In all three cell lines, formononetin increased Akt phosphorylation and Bcl-2 expression. Inhibiting miR-375 blocked these changes and increased proliferation in HUVECs, but not in MCF-7 or BT474 cells. In ovariectomized rats, formononetin increased uterine weight and caused similar changes in levels of miR-375, RASD1, ERα, and Bcl-2 in aortic ECs as in cultured HUVECs. In mice bearing MCF-7 xenografts, tumor growth was stimulated by 17β-estradiol but not by formononetin. These results suggest selective action of formononetin in ECs (proliferation stimulation and apoptosis inhibition) relative to breast cancer cells, possibly via a feedback loop involving miR-375, RASD1, and ERα. This differential effect may explain why formononetin may not increase the risk of postmenopausal breast cancer., (© 2018 Wiley Periodicals, Inc.)

Formononetin is an O-methylated isoflavone that is isolated from the root of Astragalus membranaceus, and it has antitumorigenic effects. Our previous studies found that formononetin triggered growth-inhibitory and apoptotic activities in MCF-7 breast cancer cells. To further investigate the potential effect of formononetin in promoting cell proliferation in estrogen receptor (ER)-positive cells, we used in vivo and in vitro studies to elucidate the possible mechanism. ERα-positive cells (HUVEC, MCF-7) were treated with formononetin. The CCK8 assay, Hoechst 33258, and flow cytometry were used to assess cell proliferation and apoptosis. mRNA levels of ERα, Bcl-2, and miR-375 were quantified using real-time polymerase chain reaction. ERα, p-Akt, and Bcl-2 expression was determined using Western blot. Compared with the control, low formononetin concentrations (2-6 μM) stimulated ERα-positive cell proliferation (HUVEC, MCF-7). The more sensitive HUVEC cells were used to study the relevant signaling pathway. After treatment with formononetin, ERα, miR-375, p-Akt, and Bcl-2 expression was significantly upregulated. The proliferative effect of formononetin was also blocked by a miR-375 inhibitor or raloxifene pretreatment. Additionally, in the in vivo studies, uterine weight in ovariectomized mice treated with formononetin increased significantly, but the weight dramatically decreased with raloxifene or miR-375 inhibitor pretreatment before formononetin. This study demonstrated that formononetin promoted ERα-positive cell proliferation through miR-375 activation and this mechanism is possibly involving in a miR-375 and ERα feedback loop., (© 2015 Wiley Periodicals, Inc.)

Background: Biochanin A and formononetin are O-methylated isoflavones that are isolated from the root of Astragalus membranaceus, and have antitumorigenic effects. Our previous studies found that formononetin triggered growth-inhibitory and apoptotic activities in MCF-7 breast cancer cells. We performed in vivo and in vitro studies to further investigate the potential effect of biochanin A in promoting cell proliferation in estrogen receptor (ER)-positive cells, and to elucidate underlying mechanisms. Methods: ERα-positive breast cancer cells (T47D, MCF-7) were treated with biochanin A. The MTT assay and flow cytometry were used to assess cell proliferation and apoptosis. mRNA levels of ERα, Bcl-2, and miR-375 were quantified using real-time polymerase chain reaction. Compared with the control, low biochanin A concentrations (2-6 μM) stimulated ERα-positive cell proliferation (T47D, MCF-7). The more sensitive T47D cells were used to study the relevant signaling pathway. Results: After treatment with biochanin A, ERα, miR-375, and Bcl-2 expression was significantly upregulated. Additionally, in the in vivo studies, uterine weight in ovariectomized mice treated with biochanin A increased significantly. Conclusion: This study demonstrated that biochanin A promoted ERα-positive cell proliferation through miR-375 activation and this mechanism is possibly involving in a miR-375 and ERα feedback loop. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]