Abstract：Objective To investigate effects and mechanism of decorin(DCN) on the proliferation of T24 bladder adenocarcinoma ceIls in vitro.Methods Bladder cancer T24 cell line was used as the research object. MTT assay was used to detect the effect of different concentrations and time of DCN on the survival rate of T24 cells. Flow cytometry was used to analyze the effect of DCN on the cell cycle and apoptosis of T24 cells. ELISA and Western blot were used to detect the expression of transforming growth factor-β1 (TGF-β1) and P21 protein by DCN.Results Compared with other concentrations, after T24 cells were treated with DCN at 40 and 50 μg/mL for 72 h, the inhibitory effect of DCN on T24 cells reached its maximum level（P<0.05）, the G1 phase cells increased the peak and the S phase cells decreased the lowest （P<0.001）, and the G2 phase remained unchanged throughout the treatment. When T24 cells were treated with DCN of 5, 10, 20, 30, 40 and 50 μg/mL after 72 h, there were apoptosis effect, but reached the maximum at 40 μg/mL （P<0.001）, and compared with 0 μg/mL, the DCN at 5, 10, 20, 30, 40 and 50 μg/mL after 72 h was significantly inhibited expression of TGF-β1, but the most obvious inhibitory concentration was 40 μg/mL (P<0.001). After T24 cells were treated with DCN at 40 μg/mL for 72 h, Western blot with rabbit anti-P21 antibody showed that P21 protein was up-regulated compared with 0 μg/mL(P<0.001).Conclusions Decorin can inhibit adenocarcinoma cell proliferation and induce apoptosis of adenocarcinoma cells in vitro. The pro1iferation of T24 cell could be inhibited in vitro by decorin through the mechanism of decreasing TGF-β1，increasing P21 protein expression，inhibiting cell cycle and inducing cell apoptosis.
