Expression of the miR200 Family of microRNAs in Mesothelial Cells Suppresses the Dissemination of Ovarian Cancer Cells

The TGF beta-mediated alteration of the tumor microenvironment plays a crucial role in tumor progression. Mesothelial cells are the primary components of the tumor microenvironment for ovarian cancer cells; however, the exact role of TGF beta-stimulated mesothelial cells in ovarian cancer progression remains uncertain. In this report, we examined the effects of TGF beta-treated mesothelial cells on ovarian cancer progression. We show that TGF beta-stimulated human primary mesothelial cells (HPMC) are able to promote cancer cell attachment and proliferation and the activation of the promoter activities of MMP-2 and MMP-9, which are metalloproteinases necessary for tumor invasion. Expression of the miR200 family was downregulated in HPMCs by TGF beta stimulation, and restoration of the expression of miR200 family members in HPMCs suppressed cancer cell attachment and proliferation. Downregulation of the miR200 family by TGF beta induced fibronectin 1 production, which promoted cancer cell attachment to HPMCs. Finally, we demonstrated that the delivery of the miR200s to mesothelial cells in mice inhibited ovarian cancer cell implantation and dissemination. Our results suggest that alteration of the tumor microenvironment by the miR200 family could be a novel therapeutic strategy for ovarian cancer treatment. (C) 2014 AACR.