Ca2+协同下CapG参与胃癌细胞迁移时伪足形成的机制研究

The prognosis of patients with gastric cancer is highly correlated with the invasion and metastasis. Therefore, it is of great importance to reveal the mechanism of metastasis which is still unclear. Pseudopod formation is one of the key event for invasion and migration of malignant cells. During our preliminary work, gastric cancer cells at the place of deep infiltration as well as micrometastatic lymphonode presented decressed adhesion.Furthermore, with proteiomic methods, we identified that the CapG protein differentially expressed in different stages of gastric cancer. CapG was then confirmed the relationship with invasion and metastasis of gastric cancer in cell and histological experiments. F-actin skeletion plays a major role in developing pseudopod and dynamic deform when pseudopods functionate. CapG with the assistance of calcium, could cap to dynamic F-actin barbed end to block extension, impacting the cell diformability.Therefore, we pespected that CapG coorperated with calcium particpate in pseudopod formation which mediate gastric cancer migration and invasion. Our research aims to further investigate the relationship between CapG expression and differetiation as well as TNM classification of gastric cancer. Furthermore, with methods of confocal laser scanning microscopy, live-cell imaging and Co-IP, we will study the impact of CapG expression on migration and invasion of gastric cancer cell, investigate the role of CapG in formation and function of lamellipodia and invadpodia and reveal the mechanism of that. It is our goal to explore the gastric cancer invasion and metastasis mechanism, to identify and provide scientific evidence CapG as the key protein of gastric cancer metastasis.

胃癌的浸润、转移与预后直接相关，但其机制不清。探讨胃癌的转移机制，对改善预后有重要意义。伪足形成是肿瘤细胞浸润和转移的重要条件。我们前期工作发现，早期胃癌浸润深部及微小淋巴转移灶中的癌细胞表现低粘附力。经蛋白组学研究发现，早期胃癌、进展期胃癌、正常组织中CapG蛋白显著表达差异，免疫组化发现浸润部胃癌组织中CapG表达强于浅表部，提示CapG上调可促进胃癌的浸润和转移。F-肌动蛋白参与伪足形成，其动态变化行使伪足功能，为此我们推测肌动蛋白加帽蛋白CapG在Ca2+协同下参与胃癌细胞浸润和转移时伪足的形成。本项目旨在证实CapG与胃癌分化、分期及预后的相关性；应用激光共聚焦显微镜、活细胞成像及免疫共沉淀等技术，明确CapG对胃癌细胞迁移、浸润的影响，研究其在胃癌细胞板状/侵袭性伪足形成和功能中的作用及分子机制。阐明胃癌浸润、转移机理, 为CapG作为预测胃癌转移的关键蛋白提供科学依据。

胃癌的浸润、转移与患者预后直接相关，为此探索胃癌转移机制，寻找阻断胃癌进展的分子靶点，改善预后具有重要意义。前期我们通过蛋白质组学对比早期、进展期胃癌及正常胃组织，发现CapG显著差异表达；本项目通过临床样本回顾性免疫组化结果证实CapG在胃癌组织和癌旁正常黏膜组织的表达存在显著的差异（P<0.0001），并发现CapG的表达和胃癌分期(P=0.005)及是否有淋巴结转移(P=0.00002)呈负相关，证实胃癌中CapG的作用是复杂的，在早期胃癌中发挥的作用重大。应用病毒转染、及尝试用免疫共沉淀等技术，寻找CapG蛋白对胃癌细胞迁移、浸润、增殖的影响及相关相互作用的分子机制。体外实验干扰CapG证实细胞中CapG对细胞迁移和侵袭有影响，但是对细胞增殖、细胞凋亡、细胞周期、平板克隆无影响；体内实验干扰CapG则证实CapG在体内抑制细胞增殖，可能促进体内癌细胞转移。表达谱芯片差异基因分析，进一步揭示了，CapG在胃癌中的复杂作用，提示CapG可以作为胃癌早期转移的诊断标志物和治疗靶点的潜在可能性，为揭示胃癌早期的转移提供了一种新的思路。