Fig. 2: Increased VDAC2 in NSTCs couples PFKP on mitochondrion to prevent its cytoplasmic release and inhibits PFKP-mediated glycolysis.

a Western blot analyses of VDAC2 expression in GSCs relative to the matched NSTCs derived from human GBMs. COX IV is used as a mitochondrial marker for normalization. b qRT-PCR analysis of VDAC2 expression in GSCs and matched NSTCs (**p < 0.01). c Co-immunoprecipitation analysis showing the interactions between VDAC2 and PFKP. The anti-VDAC2 antibody (upper panel) and anti-PFKP antibody (lower panel) are used for immunoprecipitation, respectively. The input samples of NSTCs are used as positive controls. d Western blot analyses of VDAC2 and PFKP in mitochondrial and cytoplasmic fractions of NSTCs expressing shRNAs against VDAC2 (shVDAC2#1 and #2) or nontargeting shRNA (shNT). COX IV is used as a mitochondrial protein marker and β-tubulin is used as a cytoplasmic protein marker for normalization. Silencing VDAC2 expression reduces the level of PFKP anchored on mitochondrion, but increases PFKP expression in cytoplasm. e PFK enzyme activity in NSTCs expressing shVDAC2 or shNT (***p < 0.001). f Analysis of the relative lactate production in NSTCs expressing shVDAC2 compared to those expressing shNT (***p < 0.001). g Co-immunoprecipitation assay showing the interactions between VDAC2 and PFKP in GSCs expressing VDAC2. The anti-VDAC2 antibody (upper panel) and anti-PFKP antibody (lower panel) are used for immunoprecipitation, respectively. The input samples of GSCs expressing VDAC2 are used as positive controls. h Analysis of PFK enzyme activity in GSCs expressing VDAC2 or control vector (***p < 0.001). i Analysis of the relative lactate production in GSCs expressing VDAC2 or control vector (***p < 0.001)