Autophagy inhibition promotes epithelial-mesenchymal transition through ROS/HO-1 pathway in ovarian cancer cells

Autophagy has been proved to be involved in metastasis of cancers. However, the detailed mechanisms are still unclear. In this work, we aim to provide the first study of the role that autophagy plays in migration and invasion in ovarian cancer cells. Transwell chamber was used to examine migration and invasion capacities. Western blotting and immunofluorescence were performed to investigate the expressions of mesenchymal markers (Vimentin, N-cadherin), epithelial marker (Keratin), transcript factor (Zeb1) and HO-1. Small interfering RNA (siRNA) was used to generate autophagy defect cells (A2780 Atg7 siRNA and Skov-3 Atg7 siRNA cells). Reactive oxygen species (ROS) were examined by flow cytometry. We found Skov-3 cells exhibited a fibroblastoid like phenotype and more invasive ability with lower level of autophagy than A2780. Transwell chamber showed that autophagy inhibition promoted migration and invasion capacities of autophagy defect cells. Western blotting showed that the expressions of mesenchymal markers and transcript factor were up-regulated, while, the expression of epithelial marker was down-regulated in autophagy defect cells. Conversely, autophagy induction could impair the migration and invasion through reversing epithelial-mesenchymal transition (EMT) in A2780 and Skov-3 cells. Besides, autophagy defect could increase the level of intracellular ROS and the expression of HO-1. NAC (ROS scavenging agent) could inhibit the migration and invasion through reversing EMT and decrease the expression of HO-1. What's more, Znpp (HO-1 inhibitor) impaired the migration and invasion through reversing EMT. In conclusion, our results suggest that autophagy inhibition may promote EMT through ROS/HO-1 pathway in ovarian cancer cells.