SHISA3基因启动子高甲基化在鼻咽癌转移中的作用及分子机制研究

Distant metastasis is the major treatment failure of nasopharyngeal carcinoma (NPC). TNM staging alone cannot accurately predict the distant metastasis-free survival rate. Recent studies have indicated that changes of DNA methylation may play important roles in nasopharyngeal carcinoma metastasis. Our previous study showed that: SHISA3 gene was hypermethylated in NPC by genome-wide methylation array and bisulfite pyrosequencing. Function experiment found overexpression SHISA3 inhibits NPC cell migration and invasion ability in vitro; Mass spectrometry and Co-IP showed that SHISA3 interacts with SGSM1, however, the molecular mechanism of SHISA3 on SGSM1 is unclear. Small clinical sample indicated SHISA3 hypermethylation is associated with poor prognosis of NPC patients. In this project, we would study the mechanism and effect of SHISA3/SGSM1 pathway in NPC metastasis by mass spectrometry, Co-IP and western blot; then we will further examine the SHISA3 promoter methylation status in 336 NPC patients with matched clinical data, and evaluated its prognostic value, which may help to provide potential new targets for individual therapy.

目前远处转移是制约鼻咽癌疗效提高的关键，单纯TNM分期不能准确预测预后。近年来发现基因的异常甲基化在肿瘤发生发展中起重要作用。我们前期结果显示：①SHISA3基因启动子区在鼻咽癌组织中存在高甲基化，过表达SHISA3可以抑制鼻咽癌细胞的迁移和侵袭；液相质谱和Co-IP实验发现SHISA3可与SGSM1蛋白结合，敲低SGSM1可逆转SHISA3对鼻咽癌细胞迁移和侵袭的抑制作用。②生存分析发现SHISA3高甲基化患者远处转移率较高。本项目拟在此基础上：①通过表达谱芯片筛选SHISA3的下游靶点及信号通路；体内外实验明确SHISA3通过SGSM1对下游靶点和信号通路的影响，阐明SHISA3基因在鼻咽癌转移中的功能及分子机制；②焦磷酸盐测序检测336例鼻咽癌组织中SHISA3甲基化水平，明确其在鼻咽癌患者转移及预后预测中的价值。拟通过本项目研究，为鼻咽癌治疗提供新靶点和实现个体化治疗奠定基础。

鼻咽癌具有高度侵袭性，远处转移是制约其疗效提高的关键，单纯TNM分期难以准确预测预后。在TNM分期基础上，鉴别鼻咽癌转移相关的分子指标，筛选出高转移风险的患者进行个体化治疗，是提高临床疗效的重要途径。DNA甲基化异常是肿瘤发生发展的重要机制，在鼻咽癌的远处转移中起重要作用。基于本项目支持，本研究取得以下进展：(1)明确SHISA3高甲基化导致其低表达可促进鼻咽癌转移，阐明SHIA3调控SGSM1进而抑制鼻咽癌转移的具体分子机制，为鼻咽癌个体化治疗提供了分子预后指标和治疗靶点；(2)将颈椎侵袭和腮腺侵袭纳入T4分期标准，提出鼻咽癌临床T分期新规范，为鼻咽癌综合治疗提供新依据。依托本项目，申请人以第一作者/共同第一作者发表SCI论文2篇，包括Cancer Res 2019、Clin Transl Med 2020。