Endothelin-1-induced epithelial to mesenchymal transition in human ovarian cancer cells via ROCK/SLUG pathway

Aim: To study the role of ROCK/SLUG signaling pathway in endothelin-1 (ET-1) induced epithelial to mesenchymal transition (EMT) in human ovarian cancer cells. Method: ET-1 was used to treat SK-OV-3 and CaOV3 cells, and the cells were transfected with constitutively active mutant of ROCK, or the cells were added with ROCK inhibitor (Y27632), or the cells were transfected with SLUG promoter-pGL3 construct and Renilla plasmid. At the end of experiment, Boyden Chamber invasion assay was used to detect the cells invasive capacity, and immunofluorescence stains were employed to observe the cells morphologic change, and reporter gene assay kit was adopted to detect SLUG promoter activity, and real time PCR and western blot were used to detect the expression of some genes related with EMT. Result: ET-1 induced morphologic and genetic changes were consistent with EMT in SK-OV-3 and CaOV3 cells, and increased the invasive capacity of the cells; ET-1 combined with its receptor endothelin A receptor (ET AR) increased the transcription of SLUG; ET-1 increased the expression of ROCK and fibronectin, and when the cells were con-transfected with constitutively active mutant of ROCK, the enhancement of fibronectin and the invasive capacity of cells were increased further. On the contrary, ROCK inhibitor Y27632 inhibited the increase of fibronectin and invasive capacity of the cells induced by ET-1 ; when the cells were transfected with constitutively active mutant of ROCK, the SLUG promoter activity was enhanced and then the transcription of SLUG was increased, the transcription of E-cadherin was reduced. On the contrary, ROCK inhibitor Y27632 inhibited SLUG promoter activity. Conclusion: ET-1 induces epithelial to mesenchymal transition in human ovarian cancer cells via ROCK/SLUG signaling pathway.