[Effects of silencing circRNA ABCB10 expression on biological properties of colorectal cancer cells].

To investigate the expression of circular ribonucleic acid ABCB10 (circABCB10) in colorectal cancer tissues and cells and its effects on cell biological behavior, radiosensitivity and growth of subcutaneous xenografts. The tumor tissue and adjacent tissue from colorectal cancer patients treated in Henan People's Hospital were collected from January 2018 to December 2018. Quantitative polymerase chain reaction (qPCR) was used to detect the expressions of circABCB10 and miR-217, cell viability was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT), cell apoptosis rate was detected by flow cytometry, cell migration and invasion were detected by Transwell method, cell radiosensitivity was detected by colony formation assay. The downstream miRNAs of circABCB10 were predicted by Circular RNA Interactome and verified by the dual luciferase reporter gene experiment. The effect of circABCB10 on the growth of transplanted tumor was examined in nude mice. The expression level of circABCB10 mRNA in colorectal cancer tissues was (3.97±2.12), higher than (1.13±0.64) in adjacent tissues (<0.05). The expression level of circABCB10 mRNA in FHC cells was (1.00±0.09), lower than that (4.53±0.44) in SW480, (3.12±0.32) in HCT116 and (3.51±0.36) in HT29 cells, respectively (all <0.05). The MTT results showed that the absorbance values of SW480 cells in si-circABCB10-1 group at 48 and 72 hours after transfection were (0.36±0.04) and (0.43±0.04), lower than (0.48±0.05) and (0.82±0.08) in circ-negative control (NC) group, respectively (all <0.05). The number of migrating cells and invasive cells in si-circABCB10-1 group were (45±8) and (34±7), lower than (106±21) and (84±15) in circ-NC group, respectively (all <0.01). The radiosensitization ratio was 1.632. The results of subcutaneous transplantation assay showed that the tumor volume and tumor weight of the si-circABCB10-1 group were significantly lower than circ-NC group after 8 days of inoculation ( all <0.05). MiR-217 is a target gene of circABCB10. Inhibition of miR-217 reversed the inhibitory effect of circABCB10 silencing on cell proliferation, migration, invasion and subcutaneous xenograft growth in nude mice and the radiosensitization activity. Silence of circABCB10 can up-regulate the expression of miR-217 to inhibit the proliferation, migration, invasion and growth of subcutaneous xenografts and increase the radiosensitivity of SW480 cells, which reveals the underlying molecular mechanism of colorectal cancer progression and provides a new sensitizing target for clinical radiotherapy of colorectal cancer.