肝癌ARID2突变激活c-MET癌基因的分子机制研究

The ARID2 gene is frequently mutated in human hepatocellular carcinoma (HCC). These loss-of-function mutations are strongly associated with a poor prognosis in HCC patients. The potential mechanism underlying this problem remains unclear, and currently no specific treatment is available for ARID2 mutated HCC. Via a transcriptome sequencing analysis in human liver tissue samples and ARID2 mutant cell line, we found that c-Met is highly likely a downstream effector of ARID2 mutations. Elucidating the detailed mechanism underlying this ARID2-cMET signaling is critical to understand the carcinogenesis of the ARID2-driving HCC, and more importantly, has a potential to identify a precision treatment strategy for this HCC subtype. We aim in this study to verify the activation of c-Met by ARID2 mutations using the CRISPR/CAS9 technique. The clinical significance and correlation of ARID2 and c-Met expression will be analyzed by immunohistochemical staining. ChIP-seq and mechanistic experiments will be further performed to study transcriptional regulation of c-MET by ARID2. In addition, the inhibitory effect of c-Met inhibitor on ARID2-mutated HCC will be evaluated in vitro as well as in xenograft HCC tumor models. Our study will provide new insights into the ARID2-driving HCC, and will potentially identify novel biomarker and therapeutic targets for HCC. The finding will provide a new strategy for the treatment of ARID2-mutated liver and establish a precision therapy for HCC patients.

ARID2在肝癌中大量突变失活，且与肿瘤预后显著负相关，但作用机理不明。新近，我们通过人肝癌组织标本及ARID2突变细胞株转录组测序分析发现c-Met可能是ARID2突变的下游激活靶基因，但机制不清。本研究拟利用CRISPR/CAS9方法在肝癌细胞株引入ARID2热点突变后检测c-Met癌基因的转录与激活变化；以免疫组化方法在肝癌标本中分析ARID2与c-Met的表达相关性及临床意义，明确ARID2对c-Met的调控作用；利用ChIP-seq结合分子生物学技术研究ARID2对c-Met的直接调控机制，揭示ARID2突变激活c-Met癌基因在肝癌中的作用及机制，为寻找肝癌新的分子标志物及潜在治疗靶点提供新思路；在体外细胞株及裸鼠移植瘤模型中分别验证c-Met抑制剂对ARID2突变阳性肝癌的治疗效果，为携带ARID2突变的肝癌亚型患者提供新的治疗策略，实现ARID2突变阳性肝癌的个性化治疗。

ARID2在肝癌中存在高频率的缺失突变，且ARID2的缺失与肿瘤的发生发展密切相关。目前尚无针对ARID2突变阳性肿瘤的治疗策略，而抑癌基因的失活是肿瘤靶向药物开发和治疗的一大难点，了解抑癌基因的下游关键通路是找到针对这一类肿瘤的有效治疗方法的重要途径。但迄今为止，有关ARID2在肝癌中具体的作用及其机制尚待进一步阐明。本研究进一步证实了ARID2在肝癌中促进肿瘤侵袭转移的作用，同时对其作用机制进入了深入的探索，我们的研究结果提示ARID2与MDM2相互作用，抑制MDM2介导的 FOXO3A泛素化降解，进而抑制肝癌细胞的迁移侵袭能力。同时，ARID2直接调节了YAP下游靶基因的染色质可及性，影响了YAP下游靶基因如CYR61、CTGF等的表达进而发挥了抑癌作用，YAP的抑制剂显著减弱了ARID2缺失细胞的迁移侵袭能力，有望成为携带ARID2缺失突变患者的可选的有效治疗方法。综上所述，本项目对ARID2在肝癌中的作用及机制进行了探讨，我们的研究提供了ARID2参与肝癌发生发展的一种重要分子机制，同时也为携带该缺失突变基因的肝癌亚型的治疗带来的新的思路和新的治疗靶点。