Hepatocyte growth factor secreted by ovarian cancer cells stimulates peritoneal implantation via the mesothelial-mesenchymal transition of the peritoneum.

A current working model for the metastatic process of ovarian carcinoma suggests that cancer cells are shed from the ovarian tumor into the peritoneal cavity and attach to the layer of mesothelial cells that line the inner surface of the peritoneum, and several studies suggest that hepatocyte growth factor (HGF) plays an important role in the dissemination of ovarian cancer. Our objectives were to evaluate the HGF expression of ovarian cancer using clinical data and assess the effect of HGF secreted from human ovarian cancer cells to human mesothelial cells. HGF expression was immunohistochemically evaluated in 165 epithelial ovarian cancer patients arranged as tissue microarrays. HGF expression in four ovarian cancer cell lines was evaluated by using semi-quantitative polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay. The effect of ovarian cancer cell derived HGF to the human mesothelial cells was assessed by using morphologic analysis, Western blotting and cell invasion assay. The effect of HGF on ovarian cancer metastasis was assessed by using in vivo experimental model. The clinical data showed a significantly high correlation between the HGF expression and the cancer stage. The in vivo and in vitro experimental models revealed that HGF secreted by ovarian cancer cells induces the mesothelial-to-mesenchymal transition and stimulates the invasion of mesothelial cells. Furthermore, manipulating the HGF activity affected the degree of dissemination and ascite formation. We demonstrated that HGF secreted by ovarian cancer cells plays an important role in cancer peritoneal implantation.