环状RNA hsa_circ_0000826靶向结合AUF1抑制结直肠癌增殖的机制研究

Colorectal cancer is one of the most common malignant tumors of the digestive system. Finding an effective therapeutic target is the key to improving patient survival. In recent years, research shows that circRNA plays an important regulatory role in tumorigenesis. Previously, we found that the expression of circ_0000826 was significantly reduced in colorectal cancer and correlated with the proliferation of colorectal cancer cells, but the specific mechanism is not clear. Through bioinformatics analysis found circ_0000826 and 3'-UTR of c-Myc mRNA have the common binding sites with AUF1. Meanwhile, circ_0000826 can regulate c-Myc protein expression. These results suggest that circ_0000826 might regulate tumor proliferation by competitively binding AUF1 and regulate c-Myc protein expression. This project intends to analyze the expression of circ_0000826 in colorectal cancer tissue and serum and the relationship between expression and prognosis; verify the proliferation role of circ_0000826 in vitro and in vivo; elucidate the mechanism that circ_0000826 inhibits the expression of c-Myc protein by binding to AUF1 to further regulate the proliferation of colorectal cancer. This project will provide a new potential target for the treatment of colorectal cancer.

结直肠癌是消化系统常见恶性肿瘤之一，寻找有效的治疗靶点是提高患者生存率的关键。近年来研究显示，环状RNA在肿瘤发生发展过程中有着重要的调控作用。我们前期研究发现环状RNA circ_0000826在结直肠癌组织中表达显著降低且与肿瘤增殖相关，但具体的机制不清楚。通过生物信息学等分析发现circ_0000826和c-Myc mRNA的3'-UTR与AUF1蛋白有共同结合位点，且circ_0000826可以调节c-Myc蛋白表达，提示circ_0000826可能通过竞争结合AUF1，抑制c-Myc蛋白表达，从而调控肿瘤增殖。本课题拟在前期工作基础上分析结直肠癌组织与血清中circ_0000826表达及预后之间的关系；体内外实验验证circ_0000826抑制增殖的作用；阐明circ_0000826通过结合AUF1抑制c-Myc蛋白表达，进而调控结肠癌增殖的作用机制，为结直肠癌治疗提供新的靶点。

结直肠癌是常见的恶性肿瘤之一，中国癌症最新统计数据显示结直肠癌发病率居第二位、死亡率排第五位。近年来研究发现环状RNA在肿瘤发生发展过程中有着重要的调控作用。前期通过高通量测序发现Circ_0000826在结直肠癌组织中低表达。通过荧光定量PCR及组织芯片原位杂交的方法验证了Circ_0000826在结直肠癌组织中显著低表达且与病人的不良预后相关。体外实验发现降低Circ_0000826的表达可以促进结直肠癌细胞的增殖，而Circ_0000826过表达则抑制了细胞增殖。裸鼠体内实验也证实过表达Circ_0000826可以抑制肿瘤增殖。通过RNA-pull-down、RIP、双荧光素酶报告基因实验明确了Circ_0000826与c-Myc mRNA的3'-UTR竞争性结合AUF1，抑制c-Myc蛋白表达，从而抑制了结直肠癌细胞的增殖。研究为结直肠癌诊断标志物筛查以及临床结直肠癌药物作用靶点的寻找提供了依据。