蛋白糖基化修饰在胃癌多药耐药中特征性改变及其作用机制研究

The resistance to chemotherapy following the surgery is the main cause of the treatment failure in gastric cancer. The dysfunction of key proteins is critical in the initiation of multidrug resistance (MDR). Meanwhile, it has been showed that glycosylation of proteins could affect drug resistance through modulating the function of proteins. Through membrane protein glycopromics and secretion proteomics, we found a set of N-linked glycoproteins whose increased expression levels promoted drug resistance, but the distinct alterations to composition and structures of the glycan and their up-streaming regulation remain unclear. Our further studies indicated that enzymes including MAN1C1, MGAT3 and FUT8 might be the key regulators in modulating the glycosylation of MDR-associated proteins. We aim to clarify the glycosylation regulation of above MDR-associated proteins by these enzymes and to establish the distinctive spectrogram of alterations to glycosylation status in chemo-resistant gastric cancer cells. We will also explore the mechanisms of the actions from these MDR-associated proteins and enzymes by cellular and molecular biological means and validate these data with clinical specimens. This project could offer the new target candiates for reversing MDR of gastric cancer specifically, but also it could help discover and identify the potential biomarkers for predicting and evaluating MDR in gastric cancer.

多药耐药是肿瘤化疗失败的主要原因，其产生与耐药相关蛋白的功能异常密切相关。研究表明糖基化修饰可通过调节耐药相关蛋白的功能影响肿瘤的多药耐药。项目组前期通过膜蛋白糖基化组学和分泌组学研究发现一组N聚糖蛋白在胃癌耐药细胞中显著升高并促进耐药，但其糖基化组成和结构所发生的特征性变化及上游调控机制尚不明确。进一步研究提示MAN1C1、MGAT3和FUT8等糖基化修饰酶的异常表达可能是胃癌耐药相关蛋白糖基化修饰异常的关键因素。因此，项目组拟通过创新性的糖蛋白质谱分析及数据解析技术明确以上糖基化修饰酶对耐药相关蛋白糖基组成和结构的调节作用，并在此基础上建立胃癌耐药相关糖基化的特征性变化谱图；通过细胞和分子生物学技术手段及临床标本验证，阐明以上关键节点分子及新发现的耐药相关糖蛋白在胃癌耐药中的分子作用机制。项目的完成将为特异性逆转胃癌耐药提供新的靶分子，并可发现监测胃癌耐药的候选分子标志物。

多药耐药是肿瘤化疗失败的主要原因，其产生与耐药相关蛋白的功能异常密切相关。研究表明糖基化修饰可通过调节耐药相关蛋白的功能影响肿瘤的多药耐药。项目组前期通过膜蛋白糖基化组学和分泌组学研究发现一组糖蛋白在胃癌耐药细胞中显著升高并促进耐药，但其糖基化组成和结构所发生的特征性变化及上游调控机制尚不明确。.项目执行期间建立了肿瘤糖基化分析方法，解析了N糖、O糖在胃癌耐药中的作用糖型和精细结构；明确了蛋白糖基化修饰在胃癌耐药中的关键作用；阐明了多个胃癌耐药相关蛋白CGA、ADAM22、HMGA/FOXL2等调控胃癌耐药的作用及机制，并阐明了消化道肿瘤非RAS突变依赖的西妥昔耐药表观遗传新机制；建立了胃肠道肿瘤耐药特征性生物样本库。本项目研究内容及进度基本按照研究计划执行，未做调整，并顺利完成计划任务。经费使用的各项支出基本按照预算执行。研究成果符合预期目标，为糖基化修饰在胃癌耐药中的作用提供了新的理论依据和实验基础，为胃癌耐药提供了新的候选分子标志物和候选靶分子。