SOX-8靶向上调GOLPH3表达促进舌鳞癌生长和转移的功能与机制研究

Patients with locoregionally advanced tongue squamous cancer had poor treatment outcomes because of high rate of distant metastasis. It is of importance to discover and identify novel targets related with metastasis. In the preliminary studies, we found that GOLPH3 was highly expressed in both tongue squamous cancer tissues and cells by protein arrays. We also found that knockdown of GOLPH3 could inhibit cell invasion, migration and proliferation in tongue squamous cancer cells. Moreover, we searched several binding sites of SOX-8 in the region of GOLPH3 promoter, and showed that SOX-8 knockdown significantly suppressed the protein expression of GOLPH3. Therefore, we speculated that GOLPH3 played an important role in the growth and metastasis of tongue squamous cancer, and was up-regulated by SOX-8. In this study, we will knockdown or overexpress SOX-8/ GOLPH3 in tongue cancer cell lines to study the effects of GOLPH3 on cell invasion, migration and proliferation. Also, we will study the role of SOX-8/GOLPH3 signaling pathway and their underlying mechanisms involved in tumor formation and metastasis in animal models. Furthermore, we will use tissue arrays and clinical data to analyze the association between SOX-8 and GOLPH3 expression, and to evaluate their relationship with tongue squamous cancer stage, metastasis, and survival, thereby identifying the clinical implications of the SOX-8/GOLPH3 signaling. This program will elucidate the molecular mechanisms of metastasis of tongue squamous cancer and provide experimental basis for the identification of the SOX-8/GOLPH3 signaling pathway as new therapeutic targets for tongue squamous cancer treatment.

转移是晚期舌鳞癌治疗失败的主要原因，发现转移相关新靶点并明确其调控机制非常重要。前期发现GOLPH3在舌鳞癌组织和细胞中高表达，且与舌癌预后不良密切相关。预实验我们敲低GOLPH3可抑制细胞侵袭、迁移和增殖；GOLPH3启动子区域存在多个SOX-8结合位点，敲低SOX-8明显下调GOLPH3表达。因此我们提出：GOLPH3高表达促进舌鳞癌生长和转移，且受SOX-8靶向调控。 本项目拟通过基因敲低或过表达在细胞水平证实SOX-8对GOLPH3的靶向调控及其对细胞侵袭、迁移及增殖的影响；建立动物模型，进一步验证SOX-8/GOLPH3信号通路在舌鳞癌生长和转移中的作用和机理；此外，利用组织芯片检测两者的表达，结合临床资料，评估其与舌癌分期、转移和生存等相关性，明确其临床意义。 本项目将揭示舌鳞癌进展的新机制，为确立SOX-8/GOLPH3信号通路作为治疗新靶点提供实验依据。

根据我们先前的研究，GOLPH3在舌鳞状细胞癌（TSCC）中明显上调，这也与生存不良有关。但是，关于GOLPH3的关键上游和下游机制仍不清楚。这项研究旨在阐明在分子水平上调节GOLPH3上调并促进TSCC发育的新机制。使用质谱和琼脂糖-链霉亲和素-生物素下拉分析，SOX8（SRY-Box 8）被鉴定为与TSCC细胞内GOLPH3启动子结合的新蛋白，该蛋白进一步被证实是GOLPH3上调的调节剂。敲低SOX8抑制了GOLPH3的启动子活性，同时在体内和体外均抑制了TSCC细胞的增殖。有趣的是，GOLPH3的过量表达挽救了SOX8敲低介导的TSCC增殖抑制作用。此外，在促进TSCC发育的同时，SOX8的外源性过表达也激活了启动子的活性以及GOLPH3的表达。此外，发现SOX8通过与TFAP2A相互作用来调节GOLPH3表达。此外，我们的结果表明，与癌旁正常对照相比，肿瘤组织内的SOX8水平升高，这与GOLPH3水平呈正相关。根据Kaplan-Meier分析，TSCC病例中SOX8和GOLPH3表达较高的预后较差。两者合计，这项研究表明SOX8通过GOLPH3的直接转录激活来增强TSCC细胞的生长，这也表明使用SOX8 / GOLPH3途径作为TSCC患者治疗靶点的潜力。