Down-regulation of PKM2 enhances anticancer efficiency of THP on bladder cancer.

Pyruvate kinase M2 (PKM2) regulates the final step of glycolysis levels that are correlated with the sensitivity of anticancer chemotherapeutic drugs. THP is one of the major drugs used in non-muscle-invasive bladder cancer instillation chemotherapy. However, low response ratio of THP (19.7%) treatment to human genitourinary tumours using collagen gel matrix has been observed. This study aims to investigate the effect of down-regulation of PKM2 on THP efficiency. Via inhibitor or siRNA, the effects of reduced PKM2 on the efficiency of THP were determined in 2 human and 1 murine bladder cancer cell lines, using MTT, cologenic and fluorescence approaches. Molecular mechanisms of PKM2 on THP sensitization were explored by probing p-AMPK and p-STAT3 levels via WB. Syngeneic orthotopic bladder tumour model was applied to evaluate this efficiency in vivo, analysed by Kaplan-Meier survival curves, body and bladder weights plus immunohistochemistric tumour biomarkers. PKM2 was overexpressed in bladder cancer cells and tissues, and down-regulation of PKM2 enhanced the sensitivity of THP in vitro. Activation of AMPK is essential for THP to exert anti-bladder cancer activities. On the other hand, down-regulating PKM2 activates AMPK and inhibits STAT3, correlated with THP sensitivity. Compared with THP alone (400 μmol L-1 , 50 μL), the combination with metformin (60 mmol L-1 , 50 μL) stopped growth of bladder cancer completely in vivo (combination group VS normal group P = .078). Down-regulating the expression of PKM2 enhances the anticancer efficiency of THP. This study provides a new insight for improving the chemotherapeutic effect of THP.