Vitamin D inhibits mesothelial-mesenchymal transition in human peritoneal mesothelial cells

Primary human peritoneal mesothelial cells (MCs) isolated from tumor-free human omentum were used. Peritoneal MCs were cultured on collagen-coated plates in RPMI-1640 media supplemented with 10% FBS and penicillin/streptomycin until confluence and then exposed to TGF-beta1 (10 ng/ml) with vehicle (DMSO) or vitamin D (calcitriol, 10 micro M) in low-serum (1% FBS) for 72 hours. In peritoneal dissemination, mesothelial cells consist part of the cancer-associated fibroblasts. Although mesothelial cells play an inherently defensive role, TGF-beta1 secreted from cancer cells induces mesothelial-mesenchymal transition, indicating that they play a pro-cancer role. Vitamin D inhibits mesothelial-mesenchymal transition. This study was conducted with the aim of inhibiting peritoneal dissemination of ovarian cancer by vitamin D.