Inhibition of glycolysis and SIRT1/GLUT1 signaling ameliorates the apoptotic effect of Leptosidin in prostate cancer cells

Since the silent information regulation 2 homolog-1 (sirtuin, SIRT1) and glucose transporter 1 (GLUT1) are known to modulate cancer cell metabolism and proliferation, the role of SIRT1/GLUT1 signaling was investigated in the apoptotic effect of Leptosidin from Coreopsis grandiflora in DU145 and PC3 human prostate cancer (PCa) cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell cycle analysis, Western blotting, cBioportal correlation analysis, and co-immunoprecipitation were used in this work. Leptosidin showed cytotoxicity, augmented sub-G1 population, and abrogated the expression of pro-poly (ADP-ribose) polymerase (pro-PARP) and pro-cysteine aspartyl-specific protease (pro-caspase3) in DU145 and PC3 cells. Also, Leptosidin inhibited the expression of SIRT1, GLUT1, pyruvate kinase isozymes M2 (PKM2), Hexokinase 2 (HK2), and lactate dehydrogenase A (LDHA) in DU145 and PC3 cells along with disrupted binding of SIRT1 and GLUT1. Consistently, Leptosidin curtailed lactate, glucose, and ATP in DU145 and PC3 cells. Furthermore, SIRT1 depletion enhanced the decrease of GLUT1, LDHA, and pro-Cas3 by Leptosidin in treated DU145 cells, while pyruvate suppressed the ability of Leptosidin in DU145 cells. These findings suggest that Leptosidin induces apoptosis via inhibition of glycolysis and SIRT1/GLUT1 signaling axis in PCa cells.