Novel Specific Pyruvate Kinase M2 Inhibitor, Compound 3h, Induces Apoptosis and Autophagy through Suppressing Akt/mTOR Signaling Pathway in LNCaP Cells

Abstract

Pyruvate kinase M2 (PKM2) is a key enzyme involved in the regulation of glycolysis. Although PKM2 is overexpressed in various tumor tissues, its functional role in cancer chemotherapy remains unexplored. In this study, we investigated the anticancer activity of a new PKM2 inhibitor, compound <b>3h</b>, through the cell metabolism and associated signaling pathways in prostate cancer cells. To evaluate the molecular basis of specific PKM2 inhibitors, the interactions of compounds <b>3h</b> and <b>3K</b> with the PKM2 protein were assessed via molecular docking. We found that, compared to compound <b>3K</b>, compound <b>3h</b> exhibited a higher binding affinity for PKM2. Moreover, compound <b>3h</b> significantly inhibited the pyruvate kinase activity and PKM2 expression. Cytotoxicity and colony formation assays revealed the potent anticancer activity of compound <b>3h</b> against LNCaP cells. Compound <b>3h</b> significantly increased the apoptotic and autophagic cell death in LNCaP cells. In addition, compound <b>3h</b> induced AMPK activation along with the inhibition of the mTOR/p70S6K pathway. Furthermore, compound <b>3h</b> significantly inhibited glycolysis and mitochondrial respiration, as determined by analyzing the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) production. Our results revealed that compound <b>3h</b> caused apoptotic and autophagic cell death in LNCaP cells by inhibiting cancer cell metabolism. Therefore, blocking glycolytic pathways using specific PKM2 inhibitors can target cancer cell metabolism in PKM2-overexpressed prostate cancer cells.