RN181 在胃癌发生发展中作用及其分子机制研究

Gastric cancer represents one of the most common malignant deadly diseases. The majority of patients are usually diagnosed at an advanced stage. Unfortunately, no effective treatments are available yet for patients with advanced gastric cancer. The efficacy of classical cytotoxic drugs seemed to reach a plateau in the treatment of gastric cancer. Greater understanding of the molecular mechanism of carcinogenesis will be essential for development of rationally designed agents that target specific molecules or pathways in advanced gastric cancer. Recently, a phase III multicentre clinical trial (called ToGA, Trastuzumab for Gastric Cancer) demonstrated that trastuzumab, a recombinant humanized IgG1 monoclonal antibody against the HER2 receptor to impede heterodimerization to other EGF receptors, is able to substantially increase overall survival in patients with advanced gastric cancer. We are interested in RN181, a RING finger domain-containing protein that has the enzymatic activity of E3-ubiquitin protein ligase. As a part of our previous work, very recently we found that RN181 expression is significantly downregulated in gastric tumour tissues compared to adjacent non-tumour tissues and inversely associated with tumour differentiation, tumour size and clinical stage respectively, suggesting that RN181 may play an essential role in gastric cancer. However, the physiological substrates, biological functions in cancer biology and molecular mechanisms of RN181 on how to regulate tumourigenesis and tumour progression are unknown. In this project, we are going to explore its biological function and clinical significance in gastric cancer by investigating the molecular mechanism of RN181 in carcinogenesis and progression of gastric cancer by using modern molecular and cellular technologies (such as yeast two hybridization, gene arrays and proteomics), in vitro tissue culture and in vivo xenograft mouse models, as well as clinical patient samples and clinicopathological information. Our objectives are to understand the biological function of RN181 in gastric carcinogenesis and tumour progression and to identify novel interactive proteins including upstream E2s and downstream substrates as well as molecular pathways for development of therapeutic strategies against advanced gastric cancer.

对进展期胃癌目前尚无有效的治疗方法。大规模3期临床试验显示，曲妥珠单抗靶向治疗可显著延长患者生存时间，给胃癌患者带来新希望。RN181是一个含RING指结构域并具E3泛素-蛋白连接酶活性的RING型锌指蛋白，但其生理功能及作用蛋白,包括上游E2酶和下游底物蛋白,全然未知。我们最新研究发现，RN181低表达于胃癌组织而高表达于癌傍正常组织；其表达水平与胃癌分化、肿瘤大小和临床分期成负相关, 提示RN181与胃癌的发生发展密切相关。然而，RN181在胃癌发生发展中的生化基础及分子调控机制，仍不清楚。本项目在我们前期研究的基础上，拟采用多种分子和细胞生物学方法、基因组学和蛋白质组学技术、细胞培养和动物模型、结合临床癌标本和病理资料，对RN181在胃癌发生发展中的作用及其分子调控机制进行系统研究，旨在阐明RN181在胃癌中作用及其关键作用蛋白，为深入了解胃癌癌变机制、研发新的靶向治疗提供新思路。

大规模 3 期临床试验显示，曲妥珠单抗靶向治疗可显著延长患者生存时间， 给胃癌患者带来新希望。 我们最新研究发现， RN181 低表达于胃癌组织而高表达于癌傍正常组织；其表达水平与胃癌分化、肿瘤大小和临床分期成负相关, 提示 RN181 与胃癌的发生发展密切相关。然而，RN181 在胃癌发生发展中的生化基础及分子调控机制，仍不清楚。本项目在我们前期研究的基础上，拟采用多种分子和细胞生物学方法、基因组学和蛋白质组学技术、细胞培养和动物模型、结合临床癌标本和病理资料，对 RN181 在胃癌发生发展中的作用及其分子调控机制进行系统研究，旨在阐明 RN181 在胃癌中作用及其关键作用蛋白，为深入了解胃癌癌变机制、研发新的靶向治疗提供新思路。实验结果显示：.1、RN181在胃癌患者中表达下调，并影响患者生存.2、RN181抑制胃癌细胞体内外生长.3、RN181调控胃癌细胞生长周期G1/S期.4、重组CDK4可挽回RN181对胃癌细胞的抑制作用.5、RN181通过抑制胃癌细胞 ERK/MAPK通路来抑制肿瘤生长.6、RN181表达的变化调节MKN28和MKN45细胞的生长.7、RN181表达的变化影响AGS细胞的凋亡.8、RN181调节GC细胞周期.9、RN181敲除后促进cyclin D1和 CDK4在AGS细胞中向核转移.10、RN181在MKN28细胞中通过抑制ERK/MAPK通路来抑制肿瘤生长