Methyl vanillate for inhibiting the proliferation, migration, and epithelial-mesenchymal transition of ovarian cancer cells via the ZEB2/Snail signaling pathway

BACKGROUND: Globally, ovarian cancer is the leading cause of female reproductive-related death, with a 5-year survival rate below 50%. Conventional therapies, such as cancer cell reduction and paclitaxel chemotherapy, have strong toxicity and are prone to drug resistance. Thus, the development of alternatives for the treatment of ovarian cancer is urgently needed. Methyl vanillate is a principal component of Hovenia dulcis Thunberg. It is known that several cancer cells are inhibited by methyl vanillate; however, whether methyl vanillate can inhibit the proliferation and migration of ovarian cancer cells still needs to be further studied. METHODS: In this study, cell counting kit 8 (CCK8) was used to examine the effects of methyl vanillic acid on the proliferation of SKOV3 cell lines and human ovarian surface epithelial cell (HOSEpiC) lines. Wound healing and transwell assays were used to determine the effect of methyl vanillate on cell migration. The expression of epithelial-mesenchymal transition (EMT) marker proteins (E-cadherin and vimentin), transcription factors (Snail and ZEB2), and skeletal proteins (F-actin) were evaluated with Western blotting. F-actin was detected by immunofluorescence assay. RESULTS: The proliferation and migration of SKOV3 cells were dose-dependently inhibited by methyl vanillate, but HOSEpiC cells were not inhibited by low concentrations of methyl vanillate. Western blotting analyses revealed a significant decrease in the expression of vimentin and a significant increase in the expression of E-cadherin in SKOV3 cells treated with methyl vanillate. This finding indicated that EMT inhibition was induced by the vanillate. Furthermore, methyl vanillate inhibited the expression of transcription factors (Snail and ZEB2) in SKOV3 cells as well as cytoskeletal F-actin assembly. CONCLUSIONS: Methyl vanillate plays an important role in inhibiting EMT and cell proliferation and the migration of ovarian cancer, likely via the inhibition of the ZEB2/Snail signaling pathway. Consequently, methyl vanillate may be a promising therapeutic drug for ovarian cancer.