LncRNA CTC-490G23.2及其m6A甲基化修饰在食管癌转移中的功能机制研究

90%的肿瘤死亡与肿瘤转移有关。长链非编码RNA(LncRNA)在生命活动中扮演重要角色，但在食管癌转移中的生物功能仍不明确，特别是其m6A甲基化修饰在肿瘤发生发展中的功能和机制研究甚少。本课题我们进行LncRNA-seq与MeRIP-seq关联分析，筛选发生m6A修饰且在食管癌转移中发挥重要作用的LncRNA，得到LncRNA CTC-490G23.2。预实验结果显示，LncRNA CTC-490G23.2在肿瘤转移中发挥重要作用，且在肿瘤尤其是转移灶组织中显著升高；和Fbxw7竞争性地与c-Myc蛋白结合减缓其泛素化降解，增强PTBP1的转录及PKM的选择性剪接生成PKM2，从而促进肿瘤细胞糖酵解和侵袭转移。我们拟从生物学功能、分子调控机制、潜在临床意义三个方面剖析LncRNA CTC-490G23在肿瘤转移中的重要角色。本项目可为肿瘤转移机制提供新方向，为临床诊疗提供新线索。

Esophageal cancer is the sixth most common cancer and the fourth most frequent cause of cancer death in China, with esophageal squamous cell carcinoma (ESCC) being the predominant histologic subtype. Tumor metastasis accounts for 90% of cancer death, and effective therapeutic strategies are largely lacking. . Non-coding RNAs (ncRNAs), including long non-coding RNAs (lncRNAs), have been implicated in many cellular processes. LncRNAs have emerged as key players in the development and progression of various diseases including cancer. N6-methyladenosine (m6A) is one of the most common and abundant types of post-transcriptional modification. However, up to now, there are few studies on the function of m6A methylation in the pathogenesis of diseases, especially in cancer progression.. In foundation studies, we established highly invasive and metastatic human ESCC sublines, which can be used to identify important regulators of cancer metastasis. The combination of LncRNA-seq and MeRIP-seq identified LncRNA CTC-490G23.2 as our research focus, which not only undergoes m6A methylation but also ranks top in the differentially expressed genes in highly metastatic ESCC cells. Our preliminary data showed that ectopic overexpression of LncRNA CTC-490G23.2 significantly enhanced invasion of ESCC cells. Further comparison and Ingenuity Pathyway Analysis (IPA) analysis of RNA-seq gene profiles of LncRNA CTC-490G23.2-overexpressing ESCC cells and control cells suggested the enrichment of glycolysis pathway. In addition, LncRNA CTC-490G23.2 was upregulated in tumor tissues and further increased in metastatic tissues, comparing with non-tumor tissues. . Mechanistically, our preliminary experiments showed that the stability of LncRNA CTC-490G23 was increased by m6A modification. LncRNA CTC-490G23.2 competes with Fbxw7 to bind with c-Myc protein to slow down c-Myc protein degradation, and then promotes PTBP1 transcription to enhance the selective splicing of PKM and PKM2 expression, therefore promoting the glycolysis process and cancer invasion and metastasis.To further validate this hypothesis, we will perform more experiments with the aims:.1. By using gain and loss-of-function studies, further investigate whether LncRNA CTC-490G23.2 promote invasion and metastasis of ESCC cells in vitro and in vivo..2. To study the downstream mechanism of LncRNA CTC-490G23.2 in cancer invasion and metastasis..3. To investigate the upstream regulatory mechanism of LncRNA CTC-490G23.2. .4. To evaluate the clinicopathological significance of LncRNA CTC-490G23.2 and its downstream effectors in esophageal cancer.. The long-term impact is to obtain a better understanding of the detailed molecular function of this oncogene in cancer. Deciphering the role and mechanism of LncRNA CTC-490G23.2 in promoting metastasis will also shed light on the treatment of esophageal cancer.