整合素β1糖基化修饰通过ERK/MAPK信号通路调控胃癌细胞多药耐药的机制研究

Multi-drug resistance of cancer cells is one of the important causes of failed therapy and the death resulting therefrom by significantly decreasing the effectiveness of chemotherapy. Integrin β1 is mainly involved in the transduction of extracellular biological signals into cells, and is closely related to the proliferation, differentiation, invasion and migration processes of cancer cells. Integrin β1 has also been examined in relation to multi-drug resistance. The change of glycosylation could affect the conformation of integrin β1 significantly, and therefore change the affinity with the ligands. The resistance for chemotherapeutic drugs could be greatly reversed after blocking the glycosylation, indicating that glycosylation has played a very critical role in integrinβ1 mediated multi-drug resistance. However, previous studies have focused on the changes in the expression level of integrin β1 protein, and the effect of glycosylation on multi-drug resistance is less reported. Therefore, this project intends to start with the glycosylation of integrin β1, combined with mass spectrometry based proteomic technologies to study the effect of glycosylation on the conformation of integrin β1 and the drug resistance of gastric cancer cells, and then, to explore the regulatory mechanism of integrin β1 to mediate multi-drug resistance in gastric cancer cells by changing its glycosylation. This project is helpful for the selection of potential therapeutic target of multi-drug resistance and the development of new antineoplastic drugs.

肿瘤细胞产生多药耐药性严重削弱了化疗药物的有效性，是导致癌症患者化疗失败而最终死亡的主要原因。整合素β1主要参与将细胞外的生物信号传递至细胞内，在调节恶性肿瘤细胞增殖、分化、浸润和迁移等方面起着重要的作用，且被证实与肿瘤多药耐药密切相关。整合素β1糖基化修饰的改变可以显著影响整个分子的构象及对配体的亲和力。我们发现，阻断其糖基化修饰后可极大逆转胃癌细胞对化疗药物的耐受性，提示糖基化修饰在整合素介导的肿瘤细胞多药耐药过程中发挥着十分关键的作用。然而，既往的研究多关注于整合素β1蛋白质表达水平的改变，糖基化修饰的改变对肿瘤多药耐药性的影响报道较少。因此，本项目拟从整合素β1的糖基化修饰入手，结合基于质谱的蛋白质组学技术，研究糖基化修饰对整合素β1结构和胃癌细胞耐药性的影响，探讨整合素β1糖基化修饰对胃癌细胞多药耐药的调控机制，为逆转肿瘤多药耐药潜在治疗靶点的筛选和新型抗肿瘤药物的开发提供帮助。

本项目以胃癌细胞多药耐药为切入点，结合蛋白质组学分析技术与分子生物学分析技术，进一步阐明肿瘤细胞的多药耐药机制，最终目标是为临床治疗提供指导，提高患者的生活质量和生存时间。因此，本项目从胃癌细胞多药耐药的机制研究、化疗药物引起脏器损伤的保护和肿瘤细胞迁移和侵袭的抑制三个方面展开，取得了如下成果：1）胃癌细胞多药耐药的机制研究方面，糖基化差异分析发现整合素β1可以通过糖基化修饰调控ERK/MAPK信号通路激活CREB1促进细胞的凋亡抵抗从而介导肿瘤细胞耐药；系统分析耐药株在蛋白质表达水平、蛋白质糖基化修饰和蛋白质磷酸化修饰水平的差异，发现RNA剪接抑制是影响胃癌细胞耐药的主要机制之一。2）化疗药物引起脏器损伤的保护方面，发现中药西青果酚酸可以通过降低氧化应激、减轻炎症反应、抑制细胞凋亡等作用缓解化学性急性肝损伤；泽泻提取物可以通过激活法尼酯X受体逆转肝内胆汁淤积；大黄中的有效成分大黄素可以通过抑制中性粒细胞蛋白酶活性缓解急性胰腺炎及其引发的肺损伤。3）肿瘤细胞迁移和侵袭的抑制方面，定量蛋白质组学分析结果表明，SFN的迁移和侵袭抑制作用与肌动蛋白细胞骨架的调节高度相关；分子对接和Western Blot结果表明，SFN通过与RAF家族蛋白结合抑制RAF/MEK/ERK通路的激活从而抑制肿瘤细胞的迁移与侵袭。以上成果为癌症的化学干预和临床治疗提供了数据基础。目前项目已发表了SCI论文7篇，其中负责人作为通讯作者SCI论文1篇，第一作者SCI论文3篇，其他作者论文3篇，协助培养硕士研究生3名，基本完成了项目预定目标。