Circular RNA RNF13 promotes proliferation of colorectal cancer cells by regulating miR-196b-5p expression / 肿瘤

ABSTRACT

Objective: To investigate the expression and clinical significance of circular RNA (circRNA) RNF13 (circRNF13) in colorectal carcinoma (CRC), and to explore the effect of circRNF13 on the proliferation of CRC cells by regulating the expression of microRNA (miRNA, miR)-196b-5p. Methods: The expression profiles of circRNAs in 6 pairs of CRC tissues and para-cancer tissues were analyzed by circRNA microarray. The expression levels of circRNF13 and miR- 196b-5p in 80 cases of human CRC and para-cancer tissues, human CRC cells and normal colorectal epithelial FHC cells were detected by real-time fluorescent quantitative PCR. The correlations of the expressions of circRNF13 and miR-196b-5p with the clinicopathological features of CRC patients were analyzed. The circRNF13 over-expression recombinant plasmid (circRNF13-OE) and the empty vector pcDNA3.1(+) as the negative control (NC) were designed and synthesised, and transfected into CRC HCT116 and HT29 cells, respectively. The proliferation capacity of HCT116 and HT29 cells transfected with circRNF13-OE and NC was detected by CCK-8 assay, and the expression level of miR-196b-5p was detected by real-time fluorescent quantitative PCR. Furthermore, HCT116 and HT29 cells were transfected with NC, circRNF13-OE, miR-196b-5p inhibitor or circRNF13-OE + miR-196b-5p mimic, then the proliferation capacity was detected by CCK-8 assay. Results: CircRNA microarray analysis showed that circRNF13 level in CRC tissues was significantly lower than that in para-cancer tissues. The result of real-time fluorescent quantitative PCR showed that the expression of circRNF13 in CRC tissues was significantly lower than that in para-cancer tissues (P < 0.001). The expression level of circRNF13 in HCT116, HT29, SW620 and SW480 cells was lower than that in FHC cells (all P < 0.001). Over-expression of circRNF13 inhibited the proliferation of HCT116 and HT29 cells (both P < 0.05). The expression of miR- 196b-5p in CRC tissues and HCT116, HT29, SW620 and SW480 cells was significantly higher than that in para-cancer tissues and FHC cells, respectively (all P < 0.001). The expression of circRNF13 was negatively correlated with the expression of miR-196b-5p in CRC tissues (P = 0.000 1, r = -0.484). The expression levels of circRNF13 and miR-196b-5p were associated with lymph node metastasis, differentiation and TNM stage of CRC (all P < 0.05). Compared with the circRNF13-OE group, the proliferation of HCT116 and HT29 cells in circRNF13-OE+miR- 196b-5p-mimics group was increased (both P < 0.05). Conclusion: The expression of circRNF13 in CRC tissues is down-regulated, and the overexpression of circRNF13 can inhibit the proliferation of CRC cells. CircRNF13 maybe promote the proliferation of CRC cells through down-regulating the expression of miR-196b-5p.