Abstract: Objective To investigate the effect of transforming growth factor β 1 (TGF-β1) on invasion, metastasis and expression of interleukin 22 (IL-22) protein of colorectal cancer cell line. Methods The colorectal cancer HCT116 cells were treated with different concentrations of TGF-β1 (0, 5, 10, 15, 20, 30, 50 μg/L) for 24 and 48 hours. The hyperplasia of HCT116 cells was detected by CCK-8 assay. The colorectal cancer HCT116 cells were divided into control group and TGF- β1 treated group. Transwell invasion and migration assay and Wound-healing assay were used to detect the effect of TGF-β 1 on the invasion and migration of HCT116 cells. RT-PCR was used to detect the effect of TGF-β1 on the expressions of TGF - β1 and IL-22 mRNA in HCT116 cells. Immunocytochemistry and Western blot assay were used to detect the expressions of TGF-β1, IL-22, STAT3 and E-cadherin protein in HCT116 cells. Results CCK-8 results show that there were no significant differences in the optical density (OD) values of HCT116 cells between different TGF-β1 concentration treatment groups (0, 5, 10, 15, 20, 30, 50 μg/L) after stimulation with TGF-β1 solution for 24 and 48 hours (P＞0.05). The invasive ability, migration ability and migration distance of cells were significantly increased after treatment with TGF- β1 (10 μg/L) for 48 hours (P＜0.01). The expression of TGF-β1 mRNA was significantly higher but the expression level of IL- 22 mRNA was significantly lower in TGF - β1 treated group than those in the control group (P＜0.01). The results of immunocytochemistry and Western blot assay showed that the expressions of TGF-β1 and STAT3 protein were significantly higher in TGF-β1 treated group than those in the control group, and the expressions of IL-22 and E-cadherin protein were significantly lower in TGF-β1 treated group than those in control group (P＜0.05). Conclusion TGF-β1 may promote the invasion and migration of HCT116 cells, but the effect on the proliferation of HCT116 cells is not obvious. TGF-β1 may inhibit the expression of IL-22 protein in HCT116 cells.

Key words: colorectal neoplasms, neoplasm invasiveness, neoplasm metastasis, transforming growth factor beta1, interleukin-22