Knockdown of ARK5 expression suppresses invasion of ovarian cancer cells.

The aim of the current study was to investigate the effects and the molecular mechanisms of ARK5 in ovarian cancer cell invasion. The plasmid pGCsilencerU6/GFP/Neo-RNAi-ARK5 and the control vector with a scramble sequence were transfected into SKOV3 cells to establish ARK5-deficient SKOV3 cells (siARK5/SKOV3) and a control cell line (Scr/SKOV3), respectively. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis were used to determine the mRNA and protein expression levels of ARK5. Migration and invasion abilities of SKOV3 cells were determined in chemotaxis and invasion assays, respectively. The epidermal growth factor-1 (EGF-1)-induced expression of matrix metallopeptidase (MMP)-2 and MMP-9, epithelial-mesenchymal transition (EMT) and phosphorylation of mechanistic target of rapamycin kinase (mTOR) in siARK5/SKOV3 and Scr/SKOV3 cells were detected by western blot. RT-PCR and western blot analyses demonstrated that the expression of ARK5 was significantly downregulated in siARK5/SKOV3 cells at the mRNA and protein levels (P<0.01). The migration and invasion abilities of siARK5/SKOV3 cells were markedly decreased compared with Scr/SKOV3 cells (P<0.01). In addition, the results demonstrated that EGF-1-induced expression of MMP-2 and MMP-9, EMT and phosphorylation of mTOR were suppressed in siARK5/SKOV3 cells as compared with Scr/SKOV3 cells (P<0.01). The current study demonstrated that ARK5 is a critical factor involved in SKOV3 cell invasion and ARK5 increases invasive potential by promoting EMT and activating the Akt-mTOR-MMPs pathway.