Expression of epithelial-mesenchymal transition (EMT) markers has been detected clinically in benign prostatic hyperplasia (BPH) tissues. To understand the molecular basis, we investigated the role of stromal microenvironment in the progression of EMT in BPH cells. First, we used cell culture supernatant from normal prostate stromal WPMY-1 cells to provide supernatant-conditioned medium (WSCM) to culture the BPH-1 cell line. Then, the morphological changes and migratory capacity were detected in BPH-1 cells. The expression of EMT markers was examined in BPH-1 cells by Western blot and immunofluorescent analysis. Finally, to investigate the role of transforming growth factor beta 1 (TGF-β1) in this process, the WSCM-cultured cells were treated with monoclonal antibody against TGF-β1 to study its effect on EMT. We found that the morphology of BPH-1 cells changed to a spindle-like shape after cultured in WSCM, and the levels of E-cadherin and cytokeratin 5/8 (CK5/8) were significantly lower than the cells cultured in ordinary medium. These BPH-1 cells were also tested positive for mesenchymal markers vimentin and a-smooth muscle actin (SMA) as well as Snail. We also found WSCM can increase the migratory capacity of BPH-1 cells. In addition, when they were treated with anti-TGF-β1, upregulation of E-cadherin and CK5/8 levels was observed but no expression of vimentin, alpha-SMA or Snail was detected. Furthermore, phosphorylated-Smad3 expression in WSCM-cultured BPH-1 cells was also suppressed by anti-TGF-β1 treatment. Our results demonstrated that stromal cell supernatant was able to induce EMT in BPH-1 cells, possibly through secreting TGF-β1 to activate Smad signaling. Our results suggest novel molecular targets for clinical treatment of BPH by modification of stromal microenvironment through inhibiting TGF-β1/Smad expression.

临床上已在良性前列腺增生（BPH）组织中检测到上皮-间质转化（EMT）标记的表达。为了了解分子基础，我们研究了基质微环境在BPH细胞EMT进程中的作用。首先，我们使用来自正常前列腺基质WPMY-1细胞的细胞培养上清液提供上清液条件培养基（WSCM）来培养BPH-1细胞系。然后，检测BPH-1细胞的形态变化和迁移能力。通过蛋白质印迹和免疫荧光分析检查BPH-1细胞中EMT标记的表达。最后，为了研究转化生长因子β1（TGF-β1）在此过程中的作用，用抗TGF-β1的单克隆抗体处理WSCM培养的细胞，以研究其对EMT的作用。我们发现，在WSCM中培养后，BPH-1细胞的形态变为纺锤形，并且E-钙粘蛋白和细胞角蛋白5/8（CK5 / 8）的水平明显低于在普通培养基中培养的细胞。这些BPH-1细胞的间质标记波形蛋白和平滑肌肌动蛋白（SMA）以及Snail也呈阳性。我们还发现WSCM可以增加BPH-1细胞的迁移能力。另外，当它们用抗TGF-β1治疗时，观察到E-钙粘着蛋白和CK5 / 8水平的上调，但未检测到波形蛋白，α-SMA或Snail的表达。此外，通过抗TGF-β1处理，WSCM培养的BPH-1细胞中的磷酸化Smad3表达也被抑制。我们的结果表明，基质细胞上清液能够诱导BPH-1细胞中的EMT，可能是通过分泌TGF-β1来激活Smad信号传导。我们的研究结果表明通过抑制TGF-β1/ Smad表达修饰基质微环境，可以为BPH的临床治疗提供新的分子靶点。