中文摘要：

目的研究二甲双胍对前列腺癌Vcap细胞增殖、侵袭及上皮间质转化（EMT）的影响，初步探讨microRNA（miRNA）相关的作用机制。方法以PBS处理组作为对照，使用不同浓度二甲双胍（1～50mmol／L）处理前列腺癌Vcap细胞，MTS比色法检测细胞的增殖能力；流式细胞术分析二甲双胍对Vcap细胞周期分布的影响；划痕和侵袭小室实验分别检测5mm01／L二甲双胍和miR30a对细胞迁移和侵袭能力的作用；使用RT—PCR和Westernblotting测定5mmol／L二甲双胍对Vcap细胞上皮指标物（E—cadherin、B—catenin）和间质指标物（Vimentin、Snail）mRNA和蛋白表达水平的影响；使用RT—PCR检测miR30a、miRl43、miRl85、miRl96、miR205的表达水平变化。结果二甲双胍抑制前列腺癌Vcap细胞的增殖，且呈浓度和时间依赖性。5mmol／L二甲双胍明显影响Vcap细胞的周期分布并显著抑制Vcap细胞的迁移和侵袭能力。二甲双胍在mRNA和蛋白水平上，显著上调Vcap细胞中E—cadherin和[3-catenin的表达（P均〈0．05），下调Vimentin和N—cadherin的表达（P均〈0．05）。进一步的实验发现，二甲双胍显著上调milL30a的表达水平（P〈0．05），而后者可显著抑制Vcap细胞的增殖和EMT的发生。结论二甲双胍明显抑制前列腺癌Vcap细胞的增殖、侵袭能力和上皮间质转化的过程。该过程可能涉及二甲双胍对miR30a的表达的上调。

英文摘要：

Objective To investigate the effects of metformin on proliferation, invasion and epithelial-mesenchymal transition （EMT） of prostate cancer Vcap cells and the possible miRNA-based mechanisms. Methods Vcap cells that were treated with PBS were used as control group. MTS assay was used to determine cellular proliferation of Vcap cells treated by metformin with various concentrations （ 1-50 mmol/L）. Flow cytometric analysis was performed to detect cell cycle distributions. Wound healing assay and martrigel invasion assay were performed to evaluate invasive capacity of cancer cells treated by 5 mmol/L metformin and miR30a; RT-PCR and Western blotting were used to detect mRNA and protein expression levels of epithelium markers （ β-catenin, E-cadherin） as well as mesenchymal marker （ Vimentin, N-cadherin）. RT-PCR was used to detect the expression levels of miR30a, miR143, miR185, miR196b and miR205.Results Metformin significantly inhibited proliferation of Vcap cells in a dose- and time-dependent manner. 5 mmol/L metformin significantly influenced cell cycle distribution and inhibited invasiveness and motility capacity of Vcap cells. Mefformin upregulated expression of E-cadherin （ P 〈 0.05 ） and 13-catenin （ P 〈 0.05 ）, but downregulated Vimentin （ P 〈 0.05） and N-cadherin （ P 〈 0.05） expression at mRNA and protein levels in Vcap cells. Significant upregulation of miR30a expression levels by metformin was identified （ P 〈 0.05 ） and further experiments confirmed that miR30a significantly inhibited proliferation and EMT of Vcap cells. Conclusion Metformin significantly inhibits cell prolifera- tion, invasion and EMT in prostate cancer Vcap cells. This process may involve upregulation of miR30a by metformin.