CBX6靶向Slug抑制食管鳞癌转移的分子机制研究

Tumour metastasis is still the major cause for failure of treatment in patients with esophageal squamous cell carcinoma (ESCC), making it urgent to further elicit the molecular mechanisms of ESCC metastasis. Previously, we found that Chromobox family protein 6 (CBX6) repressed cell invasion in HKESC1 cells. In addition, CBX6 was significantly down-regulated in the ESCC primary tissues with lymph node metastasis (55%, 27/49) compared in those without lymph node metastasis (45%, 22/49), and Western blot analysis showed that the decrease of CBX6 protein was detected in six randomly selected lymph node metastatic tissues (75%, 6/8). Down-regulation of CBX6 markedly induced the expression of Slug, and promoted cell migration and invasion. Collectively, we assume that CBX6 inhibits cell migration and invasion of ESCC by targeting Slug. In this study, with a series of biological and immunological experiments in cell and animal models, we aim to determine the expression of CBX6 and Slug and the relevant clinical significance in ESCC, to unveil the mechanism of CBX6-mediated regulation of Slug expression, and to reveal the role of CBX6/Slug signaling in cell migration and invasion in ESCC. Our study may provide evidence and new therapeutic targets for the comprehensive treatment of ESCC.

肿瘤转移仍是食管鳞状细胞癌（简称食管鳞癌或ESCC）患者治疗失败的主要原因。前期初步研究我们发现CBX6可抑制HKESC1细胞的侵袭能力；此外，伴有淋巴结转移的ESCC患者CBX6表达下调，且CBX6在食管鳞癌淋巴转移灶表达降低；细胞实验结果表明沉默CBX6显著上调Slug表达，并促进食管鳞癌细胞迁移和侵袭。因此，我们提出CBX6靶向Slug，从而抑制食管鳞癌细胞转移的假说。本项目拟采用一系列分子细胞生物学和免疫学实验，利用多种细胞株和动物模型，在细胞功能及蛋白表达调控上，明确CBX6和Slug 在食管鳞癌中的表达及临床意义，揭示CBX6调控Slug的作用机制，阐述CBX6/Slug信号在食管鳞癌细胞转移中的作用及其分子机制，从而获得CBX6参与食管鳞癌转移调控的可靠证据。

M2型丙酮酸激酶（PKM2）在包括食管鳞状细胞癌（ESCC）在内的大多数肿瘤细胞中高度表达，且对肿瘤的生长和转移具有重要意义。然而，ESCC细胞中PKM2异常表达的分子机制仍不清楚。在本研究中，我们使用生物素-链霉亲和素磁珠下拉法将ETS变异体7（ETV7）鉴定为食管鳞癌细胞中一种新的PKM2启动子结合蛋白。双荧光素酶报告基因和染色质免疫沉淀分析证实ETV7与PKM2启动子结合。在蛋白水平上ETV7可上调食管鳞癌细胞中PKM2的表达。进一步的功能研究表明，敲低ETV7抑制了食管鳞癌细胞的增殖、迁移、肿瘤发生和转移。此外，与癌旁正常组织相比，ETV7在食管鳞癌组织中的表达显著上调，并且与PKM2的表达呈正相关。Kaplan-Meier分析表明，ETV7和PKM2的高表达与总体生存率低密切相关。综上所述，我们的数据表明，ETV7通过激活PKM2信号促进食管鳞癌的进展，且ETV7/PKM2信号通路可能成为食管鳞癌治疗的新靶点。; ;