miR-3178/Notch-1通路在Genistein增加三阴性乳腺癌化疗敏感性中的作用及机制研究

Triple negative breast cancers represent a significant treatment challenge as they have a relatively poor prognosis and have no effective targeted therapy. Conventional chemotherapy continues to be the mainstay for treatment of this disease. Additional drugs increasing the efficacy of chemotherapy have commanded a great deal of recent attention. Genistein, one of the major soy isoflavones in soy products, is a relative nontoxic natural agent. Our previous studies have revealed that Genistein sensitized MDA-MB-231 cells to chemotherapy and was synergistic with Paclitaxel and Adriamycin. However, the mechanisms of the synergistic effect remain unclear. Recently, the evidence of roles for miRNA in determining drug sensitivity/resistance has been emerging and accumulating evidence is revealing that miRNA expression profiling can be correlated with the development of anticancer drug resistance. Based on our previous findings, it is supposed that low level of miR-3178 may be involvement in drug resistance through modulation Notch-1. And Genistein may up-regulate miR-3178 expression. Thus, the hypothesis is that Genistein increases the sensitivity of triple negative breast cancer chemotherapy by regulating miR-3178 expression targeting Notch-1 signaling pathway. To verify the hypothesis, we will investigate the efficacy and mechanisms of adding Genistein to chemotherapy in vitro at the cellular level. And at the same time, we will establish the appropriate animal model to demonstrate the sensitizing effect of Genistein on triple negative breast cancer chemotherapy. Our study would provide a potential approach to improve the efficacy of chemotherapy for triple breast cancer patients.

三阴性乳腺癌预后差，化疗效果存在较大的个体差异，寻找新的化疗增敏剂以提高化疗疗效一直是研究热点。本课题组前期研究发现，三羟异黄酮（Genistein）可增加紫杉醇及阿霉素抑制MDA-MB-231细胞生长的作用，增加药物敏感性，但增敏机制不明确。miRNA是肿瘤耐药研究的热点，我们首次发现miR-3178低表达可能通过Notch-1通路参与三阴性乳腺癌化疗耐药的发生，而Genistein可增加细胞中miR-3178的表达。为此提出假说：Genistein通过影响miRNA-3178的表达，调节Notch-1通路的活性，从而提高三阴性乳腺癌对化疗药物的敏感性。本项目拟通过Genistein和化疗药体外、体内联合用药研究，运用多种分子细胞实验技术及人源性乳腺微环境小鼠模型平台，研究Genistein对三阴性乳腺癌化疗的增敏作用及机制，希冀在提高三阴性乳腺癌化疗疗效方面提供一种新的思路和有效方法。

三阴性乳腺癌（TNBC）乳腺癌中预后较差的一种类型。越来越多研究法发现microRNA（miRNA）的失调及其在肿瘤进展中的作用为阐明TNBC所涉及的机制提供了新的理论基础。在本研究中，我们发现miR-3178在TNBC中显着降低，而miR-3178低表达与TNBC中的总体存活率较差相关，而在非TNBC中则不然。miR-3178的过表达通过抑制上皮-间充质（EMT）转化来抑制TNBC细胞增殖，侵袭和迁移。通过双荧光素酶报告基因测定，Notch1被验证为miR-3178的直接靶基因。miR-3178可降低Notch1的表达，Notch1表达的挽救又抑制了miR-3178对TNBC细胞增殖，转移和EMT的抑制作用。我们认为，miR-3178通过靶向抑制Notch1从而减弱TNBC细胞增殖和转移，miR-3178的挽救可能是TNBC的潜在治疗策略。