TRPC6通道在胶质瘤放疗敏感性中的作用与机制研究

Radiotherapy is the most effective supportive treatment to glioma, the most common metastasis tumor in the brain. However, it still have shown poor recovery in a population of patients. As a member of the non-selective cation channel super family, TRPC6 expression was found to be highly upregulated in glioma tissue. We have shown shat knocking down TRPC6 led to cell cycle arrest in G2 phase. More interestingly, knocking-down TRPC6 significantly increased the sensitivity of glioma tissue to radiotherapy. In this study, we aims to evaluate the correlation between TRPC6 expression in glioma tissue and the effect of radiotherapy obtained through follow-up visit in an expanded sample pool, and then assess the potential value of TRPC6 as a target of sensitizing reagent for radiotherapy. Moreover, we want to study the underlying molecular mechanism of the increased sensitization to radiotherapy by knocking-down TRPC6. Specifically, we will overexpress TRPC6 in glia cell line or knocking-down TRPC6 in glioma tissue, as well as in animal level, to investigate the mechanism. Our project provides the analysis between radiotherapy effect and the expression level of a single gene, thus expanding our understanding to the molecular mechanism of radiotherapy sensitivity, which will facilitate the development of new sensitizer for radiotherapy, and the fomulation of personalized radiotherapy strategy or molecular-targeted radiotherapy.

胶质瘤是颅内最常见的恶性肿瘤，放疗是术后最重要的辅助治疗措施之一，但临床上胶质瘤对放射治疗的敏感性常存较大差异。TRPC6通道蛋白为非选择性阳离子通道的TRP蛋白超家族中一员，我们前期研究发现TRPC6在胶质瘤组织中高表达，阻断它能使细胞周期停滞在G2期。由于处于G2期的肿瘤细胞对放射治疗十分敏感，故阻断TRPC6可能显著增加肿瘤细胞对放疗的敏感性。本课题拟通过过表达或敲除TRPC6通道蛋白进一步验证胶质瘤细胞对放疗敏感性的改变，并分别在体外细胞系、原代肿瘤细胞和动物体内层次深入研究TRPC6通道蛋白在放疗敏感性中的作用，并对其可能的分子机理进行深入探讨，着重了解TRPC6与放疗相关基因的关系及其如何影响其变化；同时采用组织芯片等方法在大临床样本中验证，对TRPC6的表达与胶质瘤患者的疗效进行偶联分析，为评价跨膜通道蛋白TRPC6作为放疗增敏的潜在靶点的可能性提供理论依据

胶质瘤是颅内最常见的恶性肿瘤，放疗是术后最重要的辅助治疗措施之一，但临床上胶质瘤对放射治疗的敏感性常存较大差异。TRPC6通道蛋白为非选择性阳离子通道的TRP蛋白超家族中一员，我们前期研究发现TRPC6在胶质瘤组织中高表达，阻断它能使细胞周期停滞在G2期。由于处于G2期的肿瘤细胞对放射治疗十分敏感，故阻断TRPC6可能显著增加肿瘤细胞对放疗的敏感性。本课题通过过表达或敲除TRPC6通道蛋白进一步验证胶质瘤细胞对放疗敏感性的改变，并分别在体外细胞系、原代肿瘤细胞和动物体内层次深入研究TRPC6通道蛋白在放疗敏感性中的作用，并对其可能的分子机理进行深入探讨，着重了解TRPC6与放疗相关基因的关系及其如何影响其变化；同时采用组织芯片等方法在大临床样本中验证，对TRPC6的表达与胶质瘤患者的疗效进行偶联分析，为评价跨膜通道蛋白TRPC6作为放疗增敏的潜在靶点的可能性提供理论依据。得到研究结论：1. TRPC6在mRNA水平和蛋白水平表达的高低与胶质瘤的病理级别相关，级别越高TRPC6的表达越高；2. TRPC6的高表达与患者预后不良相关；3. TRPC3在mRNA水平和蛋白水平表达的高低与胶质瘤的病理级别无关；4. TRPC6在胶质瘤组织中的表达与Ki67增殖指数、P53突变和EGFR扩增呈正相关，提示TRPC6可能参与胶质瘤的增殖、凋亡和血管生成等病理机理；5. TRPC6可能是胶质瘤患者放疗敏感性的指征蛋白，可能通过调节胶质瘤细胞对放疗的敏感性而影响胶质瘤患者的生存期。这类离子通道有可能成为新的治疗胶质瘤的分子靶点；6. 胶质瘤中TRPC6可能通过对ATM- CHEK2-P53的调控来降低胶质瘤对放疗的敏感性。