Abstract

Circular RNAs (circRNAs) are widely expressed in cancer tissues and participate in modulating the progression of malignant tumors, playing a pro- or anti-cancer role. This work is conducted to probe the precise role of circ_0000467 in colorectal cancer (CRC) and its regulatory mechanism. The differentially expressed circRNAs in CRC tissues and paracancerous tissues were screened by bioinformatics analysis. The expression levels of circ_0000467, miR-651-5p and DNA methyltransferases 3B (DNMT3B) mRNA in CRC tissues and cells were detected by qRT-PCR. circ_0000467 knockdown cell model was constructed to investigate the effects of circ_0000467 on CRC cell growth, migration and invasion by CCK-8 and Transwell experiments. Western blot was performed to examine DNMT3B protein expression in CRC cells. Dual-luciferase reporter gene experiment was executed to validate the targeting relationship between circ_0000467 and miR-651-5p, miR-651-5p and DNMT3B. Circ_0000467 expression and DNMT3B mRNA expression were increased and miR-651-5p expression was down-regulated in CRC tissues and cell lines. Knockdown of circ_0000467 repressed CRC cell growth, migration and invasion. Dual-luciferase reporter gene experiments validated that miR-651-5p was a direct target of circ_0000467 and miR-651-5p could specifically bind with DNMT3B 3’UTR. Functional compensation experiments showed that the regulatory effect of circ_0000467 on CRC cells’ behaviors could be partially counteracted by miR-651-5p. Circ_0000467 may enhance the growth and metastasis of CRC cells by targeting miR-651-5p and up-regulating DNMT3B expression. Circ_0000467 may be a potential diagnostic biomarker and therapeutic target for CRC.

摘要

环状RNAs（circRNAs）在癌组织中广泛表达，参与调节恶性肿瘤的进展，发挥促癌或抗癌作用。这项工作旨在探讨 circ_0000467 在结直肠癌 (CRC) 中的确切作用及其调控机制。通过生物信息学分析筛选CRC组织和癌旁组织中差异表达的circRNA。通过qRT-PCR检测CRC组织和细胞中circ_0000467、miR-651-5p和DNA甲基转移酶3B（DNMT3B）mRNA的表达水平。构建circ_0000467敲低细胞模型，通过CCK-8和Transwell实验研究circ_0000467对CRC细胞生长、迁移和侵袭的影响。进行蛋白质印迹以检查CRC细胞中的DNMT3B蛋白表达。双荧光素酶报告基因实验验证了circ_0000467与miR-651-5p、miR-651-5p与DNMT3B的靶向关系。在 CRC 组织和细胞系中，Circ_0000467 表达和 DNMT3B mRNA 表达增加，miR-651-5p 表达下调。circ_0000467 的敲低抑制了 CRC 细胞的生长、迁移和侵袭。双荧光素酶报告基因实验证实 miR-651-5p 是 circ_0000467 的直接靶标，并且 miR-651-5p 可以与 DNMT3B 3'UTR 特异性结合。功能补偿实验表明，miR-651-5p 可以部分抵消 circ_0000467 对 CRC 细胞行为的调节作用。Circ_0000467 可能通过靶向 miR-651-5p 和上调 DNMT3B 表达来增强 CRC 细胞的生长和转移。