Src/Stat3信号通路在肾细胞癌中的作用机制及其靶向治疗研究

Advanced renal-cell carcinoma (RCC) is considered a cancer with significant mortality and poor prognosis after tumor resection. Though antiangiogenesis targeting agents provide new options for therapy and have improved prognosis, around 20% patients are inherently resistant to these approaches and nearly all patients acquire resistance within 6～12 months. Evidence shows that dasatinib, an inhibitor of Src tyrosine kinase, strongly reduced viability of cultured kidney tumor cells, suggesting the potential role of Src in promoting tumor growth and metastasis. However, it’s far from clear about the mechanism of Src mediated tumor progression. Our preliminary experiments detected high protein levels of Src, Stat3, and the acetyltransferase CBP expressed in cancerous tissues of RCC patients. Moreover, Src is likely to dissociated from plasma cell membrane into cytoplasm and nucleus in CBP wide type other than knock out cells after EGF stimulation, indicating that CBP mediated acetylation may regulate Src intracellular distribution and the following Src/Stat3 pathway catalyzation. Therefore, this study aims to investigate the role of Src activation in RCC regulation. First, we plan to evaluate Src/Stat3 pathway activation, Stat3 related transcriptional factors expression and its tumorigenicity in RCC. Second, the relationship between Src acetylation and Src/Stat3 signal pathway activation will be studied. Third, the mechanism of Src intracellular distribution regulated by Src acetylation will also be explored. In addition, potential lysine sites with acetylation catalyzed by CBP will be tested and confirmed. In summary, this study will elucidate the role of acetylation of specific lysine sites in regulating Src intracellular distribution and Src/Stat3 pathway activation in RCC. It provides a novel rationale of targeting Src and its post-translational modification for the molecular biological therapy of kidney cancer.

晚期肾癌致死率高，单纯手术切除预后差，虽然抗血管生成类靶向药物对晚期肾癌患者有一定疗效，但部分患者对现有药物不敏感，且几乎全部治疗有效者在6～12月内发生疾病进展或复发。研究表明：Src蛋白激酶抑制剂dasatinib具有显著的抗肿瘤细胞生长效果，提示Src与肾癌发生发展的密切联系，但其具体作用机制尚未知晓。我们的初步研究发现：晚期肾癌组织中高表达Src 、Stat3及乙酰化酶CBP等；在CBP野生型细胞中，EGF刺激后的Src从细胞膜上掉离至细胞浆及细胞核，提示Src可能通过CBP介导的乙酰化修饰作用改变其细胞内定位，从而激活Src/Stat3信号通路，并最终促进肾癌的生成及进展。本项目中，我们将系统分析乙酰化修饰对Src细胞内分布、Src/Stat3信号通路激活以及对肾癌生物学行为的调控作用，并通过体内外实验确定Src乙酰化修饰的具体位点，从而为晚期肾癌的分子生物学治疗提供新靶点。