To investigate the effects of microRNA-142-3p targeting follistatin-?like protein 1 on proliferation, apoptosis and radiosensitivity of colorectal cancer cells.

The normal human colon cell FHC and CRC cell lines SW480, DLD-1, HCT116 and Caco-2 were cultured, the level of miR-142-3P was detected by qRT-PCR, and the level of FSTL1 protein was detected by Western Blot. MiR-142-3p mimics (miR-142-3p group) , mimics negative control (miR-NC group) , si-RNA of FSTL1 (si-FSTL1 group) , si-RNA negative control (si-?con group) were transfected into CRC SW480 cells, respectively. MTT was used to detect cell proliferation, flow cytometry was used to detect cell apoptosis, Western Blot was used to detect the levels of proliferation and apoptosis-related proteins, and cloning formation assay was used to detect radiosensitivity. Luciferase and Western Blot were used to verify the relationship between microRNA-142-3p and FSTL1 and its role in colorectal cancer. Statistical analysis was performed using t test and analysis of variance.

The levels of miR-142-3p in colorectal cancer cells SW480, DLD-1, HCT116, and Caco-2 (0.86±0.09, 1.09±0.11, 0.76±0.08, 0.98±0.10) were lower than those of normal Colonic cells FHC (2.56±0.26, t?= 18.536, 15.621, 19.851, 17.016, P?< 0.01) , FSTL1 mRNA levels (2.26±0.23, 1.39±0.14 , 2.01±0.20, 1.98±0.19) were higher than FHC cell levels (0.79±0.08, t?= 18.110, 11.163, 16.991, 17.317, P?< 0.01) , and FSTL1 protein levels (1.16±0.12, 1.09±0.11, 0.96±0.09, 0.95±0.10) were higher than FHC cell levels (0.37±0.04, t?= 18.736, 18.454, 17.972, 16.155, P?< 0.01) ; the apoptosis rate of colorectal cancer cell SW480 in miR-142-3p group (30.23±3.10) and Bax level (1.02±0.11) were higher than that in miR-con group (8.96±0.89, t?= 19.785, P?< 0.01; 0.45±0.05, t?= 14.152, P?< 0.01) , and cell proliferation activity for 72?h (1.16±0.11) , the levels of CyclinD1 (0.35±0.05) and Bcl-2 (0.38±0.04) , and the cell survival rate after 8?Gy were lower than that of the miR-con group (1.60±0.16, t?= 6.798, P?< 0.01; 1.02±0.12, t?= 15.462, P?< 0.01; 0.98±0.10, t?= 16.713, P?< 0.01; 10.35±1.25, t?= 5.742, P?< 0.01) ; the cell proliferation activity (1.05±0.11) and the levels of CyclinD1 (0.40±0.05) and Bcl-2 (0.42±0.05) in si-FSTL1 group were lower than si-con group (1.60±0.16, t?= 8.498, P?< 0.01; 1.05±0.10, t?= 17.441, P?< 0.01; 1.00±0.12, t?= 13.385, P?< 0.01) , and Bax (1.00±0.11) was higher than si-con group (0.41±0.04, t?= 15.122, P?< 0.01) ; miR-142-3p negatively regulated the expression of FSTL1, and overexpression of FSTL1 reversed the effect of miR-142-3p overexpressing on the proliferation, apoptosis and radiosensitivity of SW480 cells.

Overexpression of miR-?142-3p may inhibit the proliferation of colorectal cancer cells, induce apoptosis and enhance the sensitivity of radiotherapy by down-regulating FSTL1 expression.