AMPKα调控肿瘤代谢在结直肠癌发生发展中的作用与机制

Survival differs among patients with colorectal cancer (CRC) even for those with the same stage. The prognosis of CRC is still far from ideal in spite of curative treatment, the underlying mechanism of which remains unclear. We previously examined protein profile of 134 patients with middle stage colorectal cancer by reverse phase protein array, and correlated the protein expression with clinical characteristics as well as patients' outcomes. The most significant protein correlated with overall survival was AMPKα. Patients with high AMPKα expression had significantly poorer prognosis than those with low AMPKα. Based on the important role of AMPKα in cellular energy metabolism, we down-regulated AMPKα in colorectal cancer cell lines and found that glycolysis was significantly down-regulated, energy production decreased, apoptosis increased, colony formation and tumorigenicity decreased significantly. However, the mechanisms of how AMPKα regulates the development of colorectal cancer remains unknown. Therefore, the current project, by using CRC cell lines and animal models, is intended to explore the impact of AMPKα on the development of colorectal cancer; to clarify the regulating mechanism of AMPKα on energy metabolism in CRC cells; to uncover the role and regulating mechanism of energy metabolism in CRC. Completion of this study will not only reveal the mechanism of AMPKα in tumor promotion and clarify the role and mechanism of cellular energy metabolism in the development and tumorigenesis of CRC, but also provide new insights into the treatment and prevention for CRC.

同期结直肠患者生存差异显著，即使在根治性治疗后生存仍很不理想。所有基因型都必须通过蛋白质影响肿瘤表型，而结直肠癌蛋白表达情况及其与临床预后的关系未明。我们前期研究通过检测134例中期结直肠癌患者蛋白谱，发现肿瘤组织中AMPKα表达与总生存联系最显著，AMPKα高表达患者预后明显较差。基于AMPKα在细胞能量代谢中的重要作用，进一步研究发现下调AMPKα后，肿瘤细胞的糖酵解显著下调，能量产生明显下降，细胞凋亡增加、克隆形成及成瘤能力显著下降。然而，AMPKα调控结直肠癌发生发展的机制仍未明确。因此，本项目拟以结直肠癌细胞系及动物接种模型，探索AMPKα对结直肠癌发生发展的影响；AMPKα对结直肠癌细胞能量代谢的调控及其机制；肿瘤细胞能量代谢在结直肠癌发生发展中的作用及其机制。本研究的完成将揭示AMPKα的促瘤机制，阐明细胞能量代谢在肿瘤发生发展中的作用及机制，为结直肠癌防治提供新的理论依据。

临床分期对结直肠癌的预后影响巨大，其中I期的患者5年生存最佳（95%左右），而IV期患者5年生存最差（不到20%），而处于中间的II-III期，5年生存率的波动相对较大，从50%-90%不等。而造成同期结直肠癌患者的不同预后的机制目前还不清楚。.本项目利用蛋白质反向阵列技术检测了 134 对II-III期结直肠癌患者新鲜标本，并收集了患者的治疗和随访等临床资料，通过生物信息学分析发现了对患者预后影响最大的蛋白：磷酸化 AMPKα。接着我们在另一组患者中证实了AMPKα的表达与患者的预后呈负相关。在结直肠癌中主要表达的AMPKα亚型是AMPKα1，所以我们构建了敲降AMPKα1的结直肠癌细胞系。体内外实均表明AMPKα1能够促进结直肠癌细胞在无糖应激条件下存活和增殖。进一步地我们对机制进行了探索。我们的研究表明，AMPKα1能够磷酸化谷胱甘肽还原酶（GSR）的T507位点，增强GSR酶活性，进而增加细胞内的谷胱甘肽（GSH）含量，调节细胞内的氧化还原稳态，从而维持肿瘤细胞的存活和增殖，以及增强结直肠癌细胞对奥沙利铂的耐药。同时本项目还研发了新型纳米材料包裹的 AMPKα1 shRNA，利用其靶向结直肠癌细胞，并在细胞内和小鼠体内与奥沙利铂联用治疗结直肠癌获得了初步成效。.本项目的研究成果部分解释了II-III期结直肠癌患者的不同预后的机制，并发现新型纳米材料包裹的 AMPKα1 shRNA同奥沙利铂具有良好的联用效果。本项目的研究成果将对结直肠癌的靶向联合治疗具有重要的意义。.