代谢重编程通过O-GlcNAc修饰调控转录因子Sp1/HSF1稳定性参与肝细胞癌发生发展的机制研究

Tumor metabolic reprogramming plays a central role in cancer molecular regulation through participating the complex signaling transduction network. As a result of metabolic reprogramming, the upregulation of the activity of hexosamine biosynthesis pathway provides sufficient substrate for protein O-GlcNAc modification. Increased level of O-GlcNAcylation is associated with tumor malignant behavior and worse prognosis, whereas its role in development and progression of hepatocellular carcinoma (HCC) remains elusive. Our study showed that inhibition of O-GlcNacylation in HCC cells promoted proteasomal degradation of transcription factor Sp1 and HSF1 and down-regulated Sp1/HSF1-related pro-oncogenic signaling, therefore inhibited survival and induced apoptosis of HCC cells. Based on these results, we aim to investigate the following questions on the level of molecules, cells, animals and clinical specimens: The association between O-GlcNAcylation and HCC prognosis; the effect of tumor metabolic environment related O-GlcNAcylation on Sp1/HSF1 stability and its role in HCC development and progression; the potential anti-HCC activity of O-GlcNAc inhibiting small molecular inhibitors. This project may shed light on the role and mechanism of O-GlcNAcylation in HCC development and progression, and may provide novel molecular target for the prediction of HCC prognosis and the development of novel interventions against HCC.

肿瘤代谢重编程参与了复杂的信号转导，成为肿瘤发生发展的中心性环节之一。己糖胺生物合成活性升高是代谢重编程的表现之一，为蛋白O-GlcNAc修饰提供底物。O-GlcNAc水平上调与肿瘤恶性行为和预后相关，但其在肝细胞癌(HCC)发生发展中的具体机制还未见报道。我们的研究发现干扰HCC的O-GlcNAc修饰促进肿瘤相关转录因子Sp1及HSF1通过蛋白酶体途径降解，下调促肿瘤信号转导，抑制HCC细胞生存，诱导凋亡。在此基础上，我们将在分子、细胞、动物及临床水平进一步明确：O-GlcNAc修饰及相关分子与HCC患者预后相关性；肿瘤代谢环境相关的O-GlcNAc修饰通过调控Sp1/HSF1稳定性在HCC发生发展中的作用和相关机制；小分子抑制剂是否可通过干扰O-GlcNAc修饰抑制HCC。本项目有望揭示O-GlcNAc修饰参与HCC发生发展的作用机制，为HCC预后判断、干预手段的开发提供新的靶点。

蛋白O-GlcNAc修饰水平上调是肿瘤代谢重编程的表现之一，可能参与恶性肿瘤的发生发展。本研究立足于肝细胞癌(HCC)中蛋白O-GlcNAc修饰途径，在分子、细胞、动物及临床样本多水平开展研究，探索O-GlcNAc修饰与HCC患者预后的相关性，探讨O-GlcNAc修饰通过蛋白酶体途径调控肿瘤相关转录因子Sp1/HSF1稳定性在HCC发生发展的作用及可能的机制，同时评价雷公藤甲素(TPL)等小分子抑制剂通过调控O-GlcNAc修饰产生的抗HCC活性。结果表明，HCC中O-GlcNAc修饰水平提高可能通过蛋白酶体调控转录因子Sp1/HSF1稳定性，调节下游促生存、抗凋亡信号转导，促进HCC的发生发展，并与HCC临床预后相关。TPL等小分子抑制剂可能通过抑制O-GlcNAc修饰活性发挥其抗HCC作用。同时项目通过筛选还拓展发现了Gossypol、FTY720等小分子的抗HCC活性及其不依赖O-GlcNAc调控的作用机制，并构建了脂质-磷酸钙纳米微粒及人工外泌体载体平台，有望改善上述小分子抑制剂缺乏肿瘤特异性和高毒性的问题并实现药物及治疗核酸的共投递。项目还通过蛋白组学、转录组学方法筛选发现，除O-GlcNAc修饰通路外，尿素循环及鞘氨醇代谢通路也可能是肝脏疾病的重要参与者；同时，筛选得到了DEPDC1B、IQGAP1和UBE2S等潜在肿瘤相关分子靶标，并初步探讨了它们介导肿瘤发生发展的作用机制。项目研究结果可能为解决HCC等疾病治疗效果不佳的现状提供初步的理论依据和潜在的分子靶点，评价得出的小分子化合物可能通过进一步研究开发成为抗HCC潜在药物候选体，探索得到的其他代谢通路和分子靶点可能有助于进一步揭示肝胆胰系统恶性肿瘤发生发展的分子机制。