脂筏调控RANK/c-Met串话介导胃癌淋巴结转移的作用及机制研究

Lymphatic spread is the most common route of metastasis for gastric cancer. But, the actual mechanism remains unclear. Recent studies have shown that the receptor activator for nuclear factor κB ligand/receptor activator for nuclear factor κB (RANKL/RANK) pathway is critical for RANK-expressing breast cancer cells to home to bone and lung. However,there is no report about the role of RANKL/RANK pathway in lymph node metastasis of gastric cancer. Our original study demonstrated that: 1)RANK was expressed in human gastric cancer tissue, and was associated with lymph node metastasis.2)RANKL triggered RANK-expressing gastric cancer cells migration. Meanwhile, RANKL transactivated c-Met and lipid raft function-associated protein, Cav-1. RANKL-induced gastric cancer cells migration could be blocked by c-Met inhibitor or lipid raft inhibitor. 3) RANK combined with Cav-1 and c-Met. In the present study, we aimed to explore the role of RANKL/RANK pathway in lymph node metastasis of gastric cancer by pathological tissue samples analysis, and furthermore, to evaluate the role of Cav-1 in the cross-talk between the RANKL/RANK and c-Met pathway at the cellular level. The result of this study would be helpful in understanding the mechanism and exploring new treatment strategy for lymph node metastasis of gastric cancer.

淋巴结转移是胃癌最常见的转移途径。细胞核因子NF-kB受体活化因子配体（RANKL）具有趋化因子样作用，能诱导表达RANK的乳腺癌向骨及肺转移，但该通路是否与淋巴结转移有关尚无报告。我们的原创性研究首次证实：1）RANK表达于人胃癌组织，并与患者淋巴结转移相关；2）RANKL可诱导RANK阳性的胃癌细胞迁移，同时伴有c-Met及脂筏功能蛋白Cav-1的活化，抑制c-Met功能或脂筏形成均可抑制RANKL诱导的细胞迁移。3）RANK、c-Met与Cav-1共结合。但RANK与c-Met之间是否在脂筏中经Cav-1介导发生串话，共同激活下游信号尚不清楚。本项目旨在通过病理标本分析及细胞和分子实验，证实RANKL/RANK信号可调控胃癌淋巴结转移，RANKL/RANK在脂筏中通过与Cav-1结合，转活c-Met，共同促进淋巴结转移。其结果将为明确胃癌淋巴结转移的机制和寻找新型治疗靶点提供依据。

淋巴结转移是胃癌最常见的转移途径。细胞核因子NF-kB受体活化因子配体（RANKL）具有趋化因子样作用，能诱导表达RANK的乳腺癌向骨及肺转移，但该通路是否与淋巴结转移有关尚无报告。本实验以胃癌SGC7901、BGC823和MGC803细胞等为研究对象，在前期原创性研究基础上，进一步探讨RANKL诱导胃癌细胞迁移的机制，并深入研究脂筏在调控RANKL诱导胃癌细胞迁移的机制。并进行了一系列扩展研究。研究结果证实：1） RANKL经CAV-1活化ERK及PI3K/Akt，诱导胃癌细胞迁移。脂筏参与RANKL诱导胃癌细胞的迁移，CAV-1及RANK、c-Met共结合，RANK转活CAV-1及C-Met，并且受上游分子c-Src调控，共同参与RANKL诱导的胃癌细胞迁移。2）同时，我们的研究还证实Cav-1 介导RANK转活IGF-1R，RANK与IGF-1R 、CAV-1共结合，介导胃癌细胞的迁移。3）扩展研究显示，RANKL/RANK通路可介导胃癌及肠癌细胞对西妥西单抗的耐药。4）RANKL/RANK通路除了在胃癌转移中发挥重要的作用，我们还证实 RANKL/RANK /CAV-1介导多种恶性肿瘤细胞的迁移与转移，如肺癌、肾癌及乳腺癌，并且进一步证实在RANKL诱导的乳腺癌迁移及转移过程中，泛素连接酶Cbl-b起重要的负调控作用。5）临床数据分析结果证实: RANKL、RANK、CAV-1及C-Met表达均与胃癌患者较差的预后相关。验证了RANKL/RANK通路在胃癌的迁移、转移中发挥至关重要的作用。