Abstract B143: PKM2 metabolic activator slows lung cancer xenograft growth.

Abstract Tumor cells primarily utilize aerobic glycolysis, rather than oxidative phosphorylation, to metabolize glucose (the Warburg effect). The M2 splice form of pyruvate kinase (PKM2), the enzyme catalyzing the rate-limiting final step of glycolysis, is highly upregulated in tumors. Unlike the M1 splice form (PKM1), a constitutively active tetramer found predominantly in non-cancerous tissues, PKM2 is an inactive dimer under normal physiological conditions. Tetramerization of PKM2 requires binding of the allosteric activator fructose-1,6-bisphosphate (FBP), an upstream glycolytic intermediate, resulting in a fully active enzyme. Inactivation of PKM2 by cancer cells may allow glycolytic intermediates to be diverted into other biosynthetic pathways necessary for biomass production. The finding that PKM2 rather than PKM1 expression enhances tumorigenicity suggests that activators of PKM2 may have anti-tumor properties. We have identified and developed a series of small molecule PKM2 activators that exhibit low nM activation activity in biochemical and cell-based assays that measure pyruvate and ATP production. The extent of activation of these compounds is equal to or greater than that of FBP in biochemical assays. In addition, preliminary studies show that PKM2 activators inhibit the growth of lung cancer cell lines in vitro. The current lead compound was tested in established subcutaneously implanted A549 lung adenocarcinoma xenografts, where we observed a statistically significant 54% decrease in tumor growth, with no observable toxicity. These data suggest that this class of PKM2 activators is effective as tumor cell metabolic regulators with anti-tumor activity for lung cancer and potentially other malignancies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B143.