DataSheet_2_(-)-Sativan Inhibits Tumor Development and Regulates miR-200c/PD-L1 in Triple Negative Breast Cancer Cells.pdf

Epithelial-to-mesenchymal transition (EMT) in cancer cells could convert epithelial-like cells to mesenchymal-like cells, resulting in the increased capacity of migration and invasion of cancer cells, and is an essential step in triple negative breast cancer (TNBC) development. Recent reports exert that these EMT-activated TNBC cells are more resistant to immune attacks, with high levels of programmed death ligand1 (PD-L1). Hence, it is worthwhile to find an effective approach in inhibiting EMT-activated TNBC cells. (-)-Sativan (SA) is a naturally isolated isoflavane and could be isolated from Spatholobus suberectus, a common traditional Chinese medicine used for breast cancer treatment. It was the first time that SA exerted anti-cancer effects on breast cancer cells, according to our study. In this study, SA displayed a significant inhibitory effect on the proliferation of TNBC cells by inducing apoptosis. SA increased Bax expression, and decreased Bcl-2 protein levels. SA inhibited cell migration and invasion of MDA-MB-231 and BT-549 cells. SA could decrease N-cadherin, Snail, Vimentin, and PD-L1 expression. SA increased miR-200c expression, and decreased PD-L1 expression. Luciferase assay showed that miR-200c directly targeted PD-L1. SA promoted tumor cell susceptibility to CTL-mediated lysis. Further study confirmed that SA could inhibit PD-L1 expression and EMT by up-regulating miR-200c. In vivo results displayed that SA could also inhibit tumor volumes and weights. These findings indicate that SA exerts an inhibitory effect on TNBC cell proliferation, migration, invasion, and tumor gtrowth, and partly provide evidence for the anti-breast cancer effect of Spatholobus suberectus Dunn in TNBC therapy.

癌细胞中的上皮间质转化（EMT）可将上皮样细胞转化为间质样细胞，进而增强癌细胞的迁移与侵袭能力，是三阴性乳腺癌（TNBC）发生发展的关键环节。近期研究显示，此类经EMT激活的TNBC细胞对免疫攻击的耐受性更强，且程序性死亡配体1（PD-L1）表达水平较高。因此，探寻抑制EMT激活型TNBC细胞的有效策略具有重要价值。(-)-Sativan（简称SA）是一种天然分离得到的异黄烷类化合物，可从常用于乳腺癌治疗的传统中药密花豆（Spatholobus suberectus Dunn）中提取。本研究首次证实SA对乳腺癌细胞具有抗癌活性。本研究中，SA通过诱导细胞凋亡显著抑制TNBC细胞增殖：SA可上调Bax的表达，同时下调Bcl-2蛋白水平；SA能够抑制MDA-MB-231与BT-549细胞的迁移与侵袭能力；SA可降低N-钙粘蛋白、Snail、波形蛋白以及PD-L1的表达，同时上调微小RNA-200c（miR-200c）的表达。荧光素酶报告基因实验证实，miR-200c可直接靶向调控PD-L1。SA可增强肿瘤细胞对细胞毒性T淋巴细胞（CTL）介导的细胞裂解的敏感性。进一步研究确认，SA可通过上调miR-200c的表达，抑制PD-L1的表达与EMT进程。体内实验结果显示，SA还可抑制肿瘤体积与重量的增长。上述研究结果表明，SA可抑制TNBC细胞的增殖、迁移、侵袭以及肿瘤生长，为传统中药密花豆用于三阴性乳腺癌治疗的抗癌功效提供了部分实验依据。