RASSF8对WNT2-β-catenin信号通路的抑制在宫颈癌淋巴结转移中作用机制的研究

We recently observed that upregulation of WNT2 in patients with cervical carcinoma was closely related to lymph node metastasis and poor prognosis. RASSF8 gene and protein expression in tumor tissue, however, was significantly reduced and was positively correlated with the expression of ?-catenin inhibitor APC. We speculate that RASSF8 is likely to inhibit progression and metastasis of cervical cancer through the regulation of Wnt/ ?-catenin pathway. This project intends to firstly expand samples in paired tumor, adjacent tissues and lymph nodes, to explore correlation between RASSF8 and Wnt pathway molecules, and it's clinical significance. By establishing stable lower expression and overexpression RASSF8 cervical cancer / normal cervical epithelial cell line, the effects of RASSF8 on cell proliferation and metastasis and its correlation with the Wnt/ ?-catenin pathway, will be cleared in vitro cell experiments and animal models. Further study will clarify the functionality of RASSF8 in overexpressed Wnt2 cervical cancer cell lines, and the interaction mechanisms. Finally, based on above model, we'll explore the metastatic potential role of Wnt pathway inhibitors on cell proliferation and the influence of RASSF8 on Wnt inhibitors susceptibility. The achieved results are expected to provide a new direction for looking for new targets of cervical cancer and individualized intervention.

我们新近观察到在宫颈癌组织中WNT2的上调与患者的淋巴结转移和不良预后密切相关；而肿瘤组织中RASSF8基因和蛋白的表达则显著下调并与β-catenin抑制物APC的表达呈正相关。我们推测RASSF8很可能通过调控Wnt/β-catenin通路来抑制宫颈癌的进展和转移。本课题拟首先扩大样本在配对的肿瘤、癌旁和淋巴结组织中检测RASSF8与Wnt通路分子之间的相关性和临床意义；通过建立稳定降低和过表达RASSF8的宫颈癌/正常宫颈上皮细胞株，在体外实验和动物模型中明确RASSF8对细胞增殖和转移的影响，及其与Wnt/β-catenin通路的相关性；并在过表达WNT2细胞株中进一步明确RASSF8的功能以及它们之间相互作用与机制；最后，在上述模型中探讨Wnt通路抑制剂对细胞增殖转移潜能的作用以及RASSF8对该抑制剂药敏的影响。所得的结果可望为寻找宫颈癌治疗新靶点和个体化干预提供新的方向

复发和转移是宫颈癌治疗失败的主要原因，而经淋巴道淋巴结转移直接影响了宫颈癌患者治疗方式和远期生存，是造成宫颈癌患者预后不良的重要因素。本课题组首次报道Wnt2在有淋巴结转移的宫颈癌组织中的表达高于无淋巴结转移的宫颈癌组织（Cancer 2012）。而肿瘤组织中RASSF8基因和蛋白的表达则显著下调并与WNT通路中β-catenin抑制物APC的表达呈正相关。我们推测RASSF8很可能通过调控Wnt/β-catenin通路来抑制宫颈癌的进展和转移。本项目结合临床病理资料分析和基础医学实验阐明在宫颈癌中RASSF8是一个与预后密切相关的分子，发挥着重要的抑癌作用；RASSF8抑制宫颈癌细胞的迁移侵袭，并且很可能是通过WNT/β-catenin通路促进宫颈癌进展；RASSF8在早期宫颈癌（I/II期）中的丢失与DNA甲基化无明显相关性，具体机制尚待进一步查证；RASSF8的下调，促进淋巴管生成，导致淋巴结转移风险增加，其机制与RASSF8下调激活NF-κB通路从而调节VEGF-C表达水平有关；筛选WNT通路抑制剂后，我们发现RASSF8调节宫颈癌细胞对ICG-001的药物敏感性，ICG-001是一种其拮抗Wnt/β-catenin/TCF介导转录作用的抑制剂，RASSF8下调宫颈癌细胞对其的药物敏感性降低，癌细胞迁移侵袭能力增强。新近发现RASSF8可能通过FGF-1、NGFR、NANOG等干细胞相关蛋白，在干性维持和重塑过程中起着重要作用。本项目的成果有助于为寻找宫颈癌治疗新靶点和个体化干预提供新的方向。