ABSTRACT
@#[Abstract] Objective: To investigate the effects of silencing monocarboxylate transporter 4 (MCT4) on the proliferation, migration and invasion of prostate cancer PC3 cells and its possible molecular mechanism. Methods: RNA interference technology was used to transfect siRNA-MCT4 (si-MCT4) and negative control plasmid (si-NC) into PC3 cells, respectively. The content of lactic acid in the cell culture medium of transfected PC3 cells was detected by lactic acid assay after culturing for 96 h. The proliferation, migration and invasion ability of PC3 cells were detected by CCK-8 and Transwell assay, respectively. Western blotting was used to detect the silencing effect and the expressions of integrin β 4-FAK-SRC-MEK-ERK signaling pathway associated proteins (integrin β4, p-FAK, p-SRC, p-ERK1/2, p-MEK1/2) and EMT associated proteins (E-cadherin and N-cadherin). Results: PC3 cell line with silenced MCT4 was successfully constructed. Compared with the control group, the content of extracellular lactic acid in the PC3 cell culture medium of the si-MCT4 group was significantly decreased (P<0.01), and the proliferation, migration and invasion of cells were significantly decreased (P<0.05 or P<0.01). Compared with the control group, the protein expressions of integrin β4, p-FAK, p-SRC, p-MEK1/2, p-ERK1/2 and N-cadherin were significantly decreased (all P<0.01), while the protein expression of E-cadherin was significantly increased (P<0.01). Conclusion: Silencing MCT4 can significantly inhibit the proliferation, migration and invasion of PC3 cells, the mechanism of which may be related to the inhibition of lactic acid level in cell culture medium and suppression of integrin β4-FAK-SRC-MEKERK signaling pathway associated proteins as well as EMT associated proteins.