The expression level of ATP6V0C mRNA and protein in high metastatic potential prostate cancercell lines (PC-3M-1E8 and PC-3M) was significantly higher than that in low metastatic potential prostate cancercell lines (PC-3M-2B4 and PC-3),the expression level in PC-3M-1E8 being the highest.Follow-up tests selected PC-3M-1E8 cells for gene silencing.The expression and secretion of MMP-2 and the expression of MMP-9 in ATP6V0C siRNA transfected PC-3M-1E8 cells displayed no obvious change,but the activity of secreted MMP-9 was abated noticeably compared with the controls (P < 0.05).Extracellular hydrogen ion concentration and V-ATPase activity in interference group were both reduced significantly compared with the controls (P < 0.05).The migration and invasion capacity of ATP6V0C siRNA interfered cellsin vitro were diminished significantly compared with the controls (P < 0.05).Furthermore,a dramatic reduction of LASS2/TMSG1 mRNA and protein level after transfection of siRNA in PC-3M-1 E8 cells was discovered (P < 0.05).Confocal immunofluorescence showed a vast co-localization of ATP6V0C protein and LASS2/TMSG1 protein in plasma and membrane.The co-localization signals of control group were much stronger than those of interference group.
Conclusion:
Specific siRNA silencing of ATP6V0C gene inhibits the invasion of humanprostate cancercellsin vitro by mechanism of inhibiting V-ATPase activity and then reducing the extracellular hydrogen ion concentration,inhibiting MMP-9 activation and affecting ECM degradation and reconstruction.Meanwhile,ATP6V0C and LASS2/TMSG1 have interaction and it is likely that ATP6V0C functions as a feedback regulator of LASS2/TMSG1.