The Role And Mechanism Of ME3 In Inhibition Of Mitophagy

Objective:The aim of this study was to investigate the role of malic enzyme(ME3)in the inhibition of mitophagy in glioblastoma multiforme(GBM)cells and to provide new ideas for the clinical treatment of gliomas.Methods:(1)Using bioinformatics analysis to analyze the expression of ME3 and its correlation with mitochondrial fission and fusion indicators,autophagy pathway-related indicators;(2)Using fluorescent probes to detect MMP(mitochondrial membrane potential)and ROS(Reactive oxygen species)production;(3)Using western blot to analyze the effects of ME3 on mitochondrial fusion and fission indicators,mitophagy pathways and AMPK-m TOR pathway indicators in glioma cells.Results:(1)Clinical data showed that ME3 was negatively correlated with mitochondrial fission indicator FIS1,positively correlated with mitochondrial fusion indicators OPA1 and MFN1;negatively correlated with PINK1 in mitophagy pathways;(2)The protein and m RNA expression levels of ME3 were relatively high in U87 MG and U251 MG cell lines,and relatively low in SW1783 and LN229 cell lines.Down-regulation of ME3 in U87 MG and U251 MG cells resulted in the decrease of mitochondrial membrane potential and the production of ROS.Over-expression of ME3 in SW1783 and LN229 cells,the results were reversed;(3)Down-regulation of ME3 in U87 MG and U251 MG cells resulted in the increase of protein expression levels of mitochondrial fission-related indicators(FIS1,DRP1,MFF),while mitochondrial fusion-related indicators(MFN1,MFN2,OPA1)were decreased.The protein expression levels of PINK1,PARK2,BNIP3,BNIP3 L,OPTN,p62,LC3 and p-ubiquitin were increased in mitophagy pathway.The protein expression level of p-AMPK was increased,and the expression level of p-m TOR was significantly decreased in the AMPK-m TOR protein pathway.Over-expression of ME3 in SW1783 and LN229,the results were reversed.Conclusions:(1)ME3 promotes mitochondrial fusion and inhibits mitochondrial fission;(2)ME3 inhibits mitophagy in glioma cells;(3)ME3 decreases the protein expression level of p-AMPK and increases the protein expression level of p-m TOR.It is suggested that ME3 might play critical roles in mitochondrial dynamics and energy balance to control the biological behavior of glioma cells,providing theoretical support and new ideas for clinical treatment.