Objective To investigate the effect and mechanism of decorin (DCN) on invasion of colorectal cancer cell line HCT116 in vitro.Methods Transwell assay was employed to detect the invasion of HCT116 cells;Real-time PCR was used to detect the expression of CD133 and TIMP-2 mRNA of HCT116 cells;Western blot method was used to detect the expression of HIF-1α, CD133 and TIMP-2 protein of HCT116 cells.Results 1) When the concentrations of DCN was 0, 1 and 3 mg/L, under the conditions of normal oxygen and hypoxia, the numbers of invasive cells were (241±46), (168±46), (51±17) fields in each well (P<0.01) and (207±61), (213±64), (156±54), (44±17) fields in each well (P<0.01).2) Under the normoxic conditions, the TIMP-2 mRNA and protein in HCT116 cells were increased by DCN (3 mg/L) (P<0.01), but that of CD133 were not affected.3) DCN (3 mg/L) significantly decreased the expression of HIF-1α/CD133/TIMP-2 protein in HCT116 cells under hypoxia (P<0.01), but had no significant effect on the expression of CD133 mRNA.ConclusionsUnder the conditions of hypoxia and normal oxygen, DCN may function through different mechanisms to inhibit the invasion of colorectal adenocarcinoma cell line HCT116 in vitro.