Expression of the miR200 family of microRNAs in mesothelial cells suppresses the dissemination of ovarian cancer cells.

The TGFβ-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 TGFβ-stimulated mesothelial cells in ovarian cancer progression remains uncertain. In this report, we examined the effects of TGFβ-treated mesothelial cells on ovarian cancer progression. We show that TGFβ-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 TGFβ stimulation, and restoration of the expression of miR200 family members in HPMCs suppressed cancer cell attachment and proliferation. Downregulation of the miR200 family by TGFβ 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.