Mechanistic Study And Role Of Downregulating PKM2 On Inhibitory Efficiency Of THP To Bladder Cancer

Purpose: Pyruvate kinase M2(PKM2)rate-limiting enzyme in the glycolysis process.PKM2 levels were correlated with sensitivity of anticancer chemotherapeutic drugs including cisplatin and geftinib.THP,one of the most popularly chemotherapeutic drugs used to treatment of bladder cancer in clinic.Previous studies showed that low response ratio of THP(19.7%)treatment to human genito-urinary tumors using collagen gel matrix.However,the correlation between PKM2 levels and THP sensitivity has no studied,This study aims to investigate the effect of down-regulation of PKM2 on THP efficiency.Methods: Via inhibitor or siRNA,the effects of reduced PKM2 on the efficiency of THP were determined in bladder cancer cell lines,via MTT,cologenic,Scratch experiments and fluorescence approaches.Molecular mechanisms of PKM2 on THP sensitization were explored via probing Key proteins levels by WB and RT-PCR.Syngeneic orthotopic bladder tumor model was applied to evaluate this efficiency in vivo,analyzed by Kaplan-Meier survival curves,body and bladder weights plus immunohistochemistric tumor biomarkers.Results: PKM2 is overexpressed on bladder cancer cells and tissues,THP inhibited the growth of various bladder cancer cells in dose dependent fashion.And the ability to inhibit the clonal formation of bladder cancer cells was significantly increased in a dose-dependent manner.Importantly,Down-regulation of PKM2 enhanced the sensitivity of THP in vitro.In Mechanismly,activation of AMPK is essential for THP to exert anti-bladder cancer.In the other hands,down-regulating PKM2 activates AMPK and inhibits STAT3,correlated to THP sensitivity.Compared with THP alone(400?M,50?l,twice per week for two weeks intravesically),the combination with PKM2 inhibitor(metformin,60 mM,50?l,twice per week for two weeks intravesically)abolished growth of bladder cancer completely in vivo(combination group VS normal group P=0.078).Conclusions: Down-regulation of PKM2 activates AMPK and inhibits STAT3,thereby enhancing the anti-bladder effect of THP;knocking-down of PKM2 or STAT3 can significantly activate AMPK via siRNA in bladder cancer cells;activation of AMPK is a necessary condition for the anticancer efficiency of THP.This study may provide a new insight for improving the chemotherapeutic effect of THP...