CRTC2 Forms Co-condensates with YTHDF2 that Enhance Translational Efficiency of m6A-Modified mRNAs to Drive Hepatocarcinogenesis and Lenvatinib Resistance (RNA-seq). CRTC2 Forms Co-condensates with YTHDF2 that Enhance Translational Efficiency of m6A-Modified mRNAs to Drive Hepatocarcinogenesis and Lenvatinib Resistance (RNA-seq)

As the third most common cause of cancer-related mortality, hepatocellular carcinoma (HCC) is a global health concern. Despite its prevalence, treatment options are limited, underscoring the need to identify potential therapeutic targets and strategies. Here, we identified amplification of CRTC2, situated in the 1q21.3 region, due to copy number alterations in HCC. In a cohort of patients with HCC, CRTC2 protein levels were frequently elevated and correlated with poor prognosis. Genetic depletion of CRTC2 significantly impeded the onset and progression of HCC in mouse models. CRTC2 formed cytoplasmic condensates that recruited the m6A reader YTHDF2. Furthermore, CRTC2 promoted the translocation of m6A-modified mRNAs from decay sites to polyribosomes by interacting with PABP1. The activities of CRTC2 counteracted YTHDF2-mediated mRNA degradation to enhance the translational efficiency of specific mRNAs, including those encoding LRP5 and c-Jun. Targeting CRTC2 in hepatocytes using AAV8.sgCRTC2 elicited substantial therapeutic benefits in HCC mouse model and significantly enhanced the sensitivity to lenvatinib. Together, this research elucidates the pivotal role and underlying molecular mechanisms of CRTC2 in hepatocarcinogenesis and lenvatinib-resistance, highlighting its potential clinical and therapeutic applications. Overall design: To investigate the function of CRTC2 in HCC, we established stable HCCLM3 cell lines overexpressing CRTC2-WT or CRTC2-R>A. For RNA-seq, comparative gene expression profiling analysis of RNA-seq data for Control, CRTC2-WT and CRTC2-R>A in HCCLM3 cells.

肝细胞癌（hepatocellular carcinoma, HCC）是癌症相关死亡的第三大常见病因，属于全球性健康难题。尽管其发病率居高不下，现有治疗手段却十分有限，凸显了挖掘潜在治疗靶点与策略的迫切需求。
本研究通过分析肝细胞癌的拷贝数变异，鉴定出位于1q21.3区域的CRTC2基因扩增。在一组肝细胞癌患者队列中，CRTC2蛋白水平常呈异常升高状态，且与不良预后显著相关。在小鼠模型中，CRTC2的基因耗竭可显著阻碍肝细胞癌的发生与进展。CRTC2可形成细胞质凝聚体，招募m6A阅读蛋白（m6A reader）YTHDF2。此外，CRTC2通过与PABP1相互作用，促进m6A修饰的mRNA从降解位点向多聚核糖体转运。CRTC2的上述活性可拮抗YTHDF2介导的mRNA降解，增强包括LRP5与c-Jun编码基因在内的特定mRNA的翻译效率。利用AAV8.sgCRTC2靶向肝细胞中的CRTC2，可在肝细胞癌小鼠模型中产生显著的治疗获益，并显著提升肿瘤对仑伐替尼（lenvatinib）的敏感性。综上，本研究阐明了CRTC2在肝细胞癌变及仑伐替尼耐药中的关键作用与潜在分子机制，凸显了其临床治疗应用潜力。
实验整体设计：为探究CRTC2在肝细胞癌中的功能，我们构建了过表达CRTC2-WT或CRTC2-R>A的稳定HCCLM3细胞系。针对RNA测序实验，我们对HCCLM3细胞中对照组、CRTC2-WT组及CRTC2-R>A组的RNA-seq数据开展了比较基因表达谱分析。