Shiliang Dong,Minrui Ma,Ming Li,Yuexin Guo,Xiaoxiao Zuo,Xiaobin Gu,Mingzhi Zhang,Yonggang Shi
Maternally expressed 3 (MEG3) and RNA binding motif single stranded interacting protein 3 (RBMS3) are abnormally expressed in breast cancer susceptibility genes (BRCA), but the mechanism of the two in breast cancer (BC) is unclear. By performing in vivo and in vitro experiments, we found that MEG3 and RBMS3 were low-expressed, negatively correlated with high-expressed miR-141-3p, were positively correlated with each other in BC. MEG3 targeted miR-141-3p, and miR-141-3p targeted RBMS3. MEG3, which was mainly distributed in BC cytoplasm, could down-regulate miR-141-3p and up-regulate RBMS3, and reverse effect of miR-141-3p on related gene expressions and on promoting cancer development. Overexpressed MEG3 inhibited growth of xenografts, promoted cell apoptosis via regulating apoptosis related factors, and up-regulated RBMS3 expression but down-regulated miR-141-3p. The findings of this study showed that MEG3 inhibited proliferation and promoted apoptosis of BC cells through the miR-141-3p/RBMS3 axis, and MEG3 inhibited growth of xenografts through miR-141-3p.
Mengzhen Gu,Xiaoqing Xu,Xiaoping Wang,Yun Wang,Yu Zhao,Xiaoxian Hu,Lu Zhu,Zhenzhong Deng,Chao Han
Histone lysine-specific demethylase 1 (LSD1) is hyperactive in breast cancer, which is associated with the metastasis of the tumor. Current irreversible LSD1 inhibitors are all synthesized by covalently binding to the flavin adenine dinucleotide cofactor, which often have side effects due to the high affinity for a variety of targets. Here, we identified isoforsythiaside (IFA), a natural phenylpropanoid glycoside isolated from Forsythia suspensa, as a novel covalent inhibitor of LSD1. The target ligand fishing technique and LC–MS/MS analysis identified that IFA could covalently bind to the Ser817 residue of LSD1 by α,β-unsaturated ketone moiety to block the amine oxidase-like domain of LSD1. Moreover, RBMS3/Twist1/MMP2, the downstream signaling pathway of LSD1, was activated after IFA treatment to inhibit the metastasis of MDA-MB-231 cells in vitro and in vivo. This study provided novel molecular templates for development of LSD1 covalence-binding inhibitor and laid a foundation for developing agents against breast carcinoma metastasis for targeting LSD1.
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