Antiproliferative effect of rosiglitazone on autosomal dominant polycystic kidney disease cystic lining epithelial cells / 中华肾脏病杂志

ABSTRACT

Objective To investigate the antiproliferative effect of rosiglitazone, a thiazolidinedione (TZD) on autosomal dominant polycystic kidney disease (ADPKD) cystic lining epithelial cells and to explore the underlying molecular mechanism. Methods ADPKD cysticlining immortalized epithelial (WT9-12) cells were stimulated by rosiglitazone with different concentrations. After treatment, MTT method was performed to detect the level of proliferation; flow cytometry was used to determine the cell cycle distribution and the apoptosis rate. Western blotting was used to detect the protein expressions of mTOR, p70S6K, 4E-Bp1, PPARγ PPARγ siRNA was transfected into WT9-12 cells to knock down the expression of PPARγ Results Treatment of WT9-12 cells with rosiglitazone resulted in a dose-dependent and time-dependent strong inhibition of cell proliferation, an accumulation of cells in the G0/G1 phase (rosiglitazone 50 μmol/L 65.43%,rosiglitazone 100 μmol/L 64.02%, control 49.65% ) and 6% apoptosis at high concentration (rosiglitazone 200 μmol/L). Rosiglitazone reduced the phosphorylation of p70S6K in a dosedependent and time-dependent manner. The levels of phosphorylated mTOR and 4E-Bp1, the latter being a downstream substrate of mTOR related mRNA translation initiation, were not changed by rosiglitazone. Cells were pre-incubated with GW9662, a PPARγ antagonist, before the treatment with rosiglitazone, the inhibition of p70S6 kinase phosphorylation by rosiglitazone was partially prevented by GW9662 (P＜0.01). Then PPARγ siRNA was transfected into WT9-12 cells, in contrast to untransfected control or cells transfected with an irrelevant siRNA, rosiglitazone did not cause an obvious inhibition of p70S6 kinase phosphorylation in PPARγ knock-down.Conclusion Rosiglitazone inhibits the proliferation of ADPKD cystic lining epithelial cells, and down-regulates p70S6 kinase phosphorylation through mTOR-independent and PPARγ-dependent signal pathway.