降低eEF1A1调控肝癌细胞ISG化增强其化疗敏感性的机制研究

Primary hepatocellular carcinoma (PHC) seriously threatens to people health with low sensitivity to chemotherapy. To improve the chemosensitivity of PHC have become a hot problem. The studies found that ISGylation is closely related with the chemosensitivity of tumor cells. It confirmed that the upregulation of ISGylation can increase chemosensitivity of tumor cells. The level of ISGylation was regulated by E2 enzyme UBCH8. Reducing the expression of eukaryotic translation elongation factor 1A1 (eEF1A1) can increase the chemosensitivity of tumor. In our previous study, we found high expression level of eEF1A1 while the low level of ISGylation in PHC. In liver cancer cells, reducing eEF1A1 enhanced the level of ISGylation, and enhanced sensitivity of liver cancer cells to doxorubicin through inhibiting cell growth and promoting apoptosis. But the molecular mechanism of these remains unclear. Therefore, we speculate that eEF1A1 influence the chemosensitivity of liver cancer cells by regulating ISGylation through UBCH8. In this study: Firstly, it confirmed the relevance of eEF1A1 and ISGylation level in HCC. Then it confirmed that the eEF1A1 regulation of ISGylation through UBCH8 can influence the chemosensitivity of liver cancer cells. Finally, these were further confirmed in vivo. Elucidate the eEF1A1 regulation of liver cancer chemosensitivity path by affecting ISGylation through UBCH8, which provides the theoretical basis of regulating the chemosensitivity of PHC and the future generation of targeted anticancer agents.

原发性肝癌危害人类健康且化疗敏感性低，提高肝癌化疗敏感性已成为热点问题。研究发现提高肿瘤细胞ISG化水平可以增加其化疗敏感性，且ISG化水平受E2 酶UBCH8的调控。降低真核翻译延伸因子1A1 (eEF1A1)的表达可以增加肿瘤化疗敏感性。我们前期研究发现肝癌组织中eEF1A1水平呈高表达，ISG化水平则低表达；降低肝癌细胞eEF1A1表达引起ISG化水平的增加，并抑制细胞生长和促进细胞凋亡，提高肝癌细胞对阿霉素的敏感性，但具体机制仍不清楚。我们推测eEF1A1可通过UBCH8调控ISG化影响肝癌细胞化疗敏感性。本课题拟收集临床肝癌组织确认eEF1A1与ISG化水平的相关性，然后明确eEF1A1调控ISG化影响肝癌化疗敏感性的作用机制，并利用体内研究进一步证实。明确eEF1A1通过调控肝癌细胞ISG化影响其化疗敏感性的作用机制，为调节肝癌化疗敏感性提供新的理论基础和特异性药物治疗靶点。

真核翻译延伸因子1A1 (eEF1A1)和ISG化都能够调节肿瘤细胞化疗敏感性。在本研究中，我们分析了eEF1A1和ISG化在肝癌组织和肝癌细胞中的表达相关性，结果表明在肝癌组织中eEF1A1蛋白表达明显上调而ISG化水平则明显下调，肝癌细胞中eEF1A1表达与ISG化水平呈负相关。RNAi沉默eEF1A1的表达能够增加ISG化的水平，增加凋亡相关基因Bax的表达而降低Bcl-2的表达，并增加肝癌细胞对化疗药的敏感性。相反，过表达eEF1A1能够降低ISG化的水平，降低凋亡相关基因Bax的表达而增加Bcl-2的表达，同时降低肝癌细胞对化疗药的敏感性。进一步研究发现eEF1A1通过UBCH8调控ISG化影响肝癌细胞化疗敏感性。我们的结果揭示了一个新的肝癌化疗敏感性的调控通路机制，为调节肝癌化疗敏感性提供新的理论基础和特异性药物治疗靶点。