罗格列酮对人多囊肾囊肿衬里上皮细胞增殖的抑制作用

目的 探讨过氧化物酶体增殖物激活受体γ（PPARγ）激动剂罗格列酮对常染色体显性遗传性多囊肾病（ADPKD）囊肿衬里上皮细胞增殖的抑制作用及其机制。 方法 MTT法检测罗格列酮对ADPKD囊肿衬里上皮细胞系（WT9-12）细胞增殖的作用；流式细胞术检测罗格列酮对WT9-12细胞周期及凋亡的影响；Western印迹法检测罗格列酮对哺乳类动物的雷帕霉素靶蛋白（mTOR）-p70核糖体S6激酶（p70S6K）信号通路的影响。给予PPARγ特异性抑制剂GW9662及PPARγ siRNA瞬时转染WT9-12细胞，检测罗格列酮对细胞增殖及对mTOR信号通路的作用是否为PPARγ依赖性的。 结果 罗格列酮抑制WT9-12细胞增殖，此作用在0~200 mol/L范围内呈剂量依赖性及时间依赖性，作用72 h的50%抑制率浓度为100 mol/L。细胞周期分析显示，罗格列酮（50、100 mol/L）作用后，G0/G1期细胞较对照组显著增多（65.43%、64.02%比49.65%，P ＜ 0.05）。50、100 mol/L罗格列酮对细胞凋亡影响不大，高浓度（200 mol/L）罗格列酮可使凋亡细胞达6%（正常对照组为4%）。罗格列酮可呈时间及剂量依赖性下调WT9-12细胞p70S6K磷酸化表达，而对mTOR及其另一个下游4E结合蛋白1（4E-BP1）磷酸化水平无明显影响。加入GW9662及转染PPARγ siRNA阻断PPARγ表达后，可部分阻断罗格列酮对p70S6K磷酸化的影响（P ＜ 0.01）。 结论 罗格列酮可抑制ADPKD囊肿衬里上皮细胞增殖和阻滞细胞周期，可不依赖于mTOR途径直接下调p70S6K磷酸化表达。罗格列酮对ADPKD囊肿衬里上皮细胞p70S6K磷酸化的影响是PPARγ依赖性的。

Antiproliferative effect of rosiglitazone on autosomal dominant polycystic kidney disease cystic lining epithelial cells

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.