Abstract 2825: Characterization of a novel small molecule antagonist of 6-phosphofructo-2-kinase that suppresses glucose metabolism and tumor growth

Abstract

Abstract Over-expression of HIF-1α, activation of Ras and loss of p53 tumor suppressor function are associated with the development of human cancers and each of these genetic alterations converge on glycolysis by activating the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB). The PFKFB enzymes interconvert fructose-6-phosphate (F6P) and fructose-2,6-bisphosphate (F2,6BP) and F2,6BP is an allosteric activator of 6-phosphofructo-1-kinase (PFK-1), a rate-limiting enzyme and control point in the glycolytic pathway. There are four PFKFB family members which are encoded by separate genes (PFKFB1-4) and characterized by distinct kinase:bisphosphatase ratios. The PFKFB3 family member is of particular interest since it has been found to be activated in human cancer cell lines and tumors, to be increased by hypoxic exposure via HIF-1α and by oncogenic Ras, and to be required for tumorigenic growth. We recently discovered a competitive antagonist of PFKFB3 (3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one [3PO]) that reduces the glucose uptake, F2,6BP, lactate secretion, steady-state concentration of ATP, and growth of multiple transformed cell lines. Using a rationale design based approach, we have synthesized derivatives of 3PO and identified a compound (PFK-015) that: (i) more potently inhibits recombinant PFKFB3 (IC50:110 nM); (ii) inhibits PFKFB3 activity in cancer cells (IC50: 20 nM); (iii) is not a Pgp substrate as determined by transport and cell permeability assays in Caco-2 and MDCK-MDR1 (Papp A-B / B-A results 1.8 / 4 and 5 / 5 10−6 cm/s); (iv) inhibits cancer cell proliferation in a panel of 17 cancer cell lines; and (v) suppresses glucose uptake in cancer cells. Rodent PK studies following IV dosing at 5 mg/kg resulted in a profile with a satisfactory half-life (5.1 hours), exposure (AUCinf 1804 ng.h/ml), tissue distribution (Vd 20.5 L/kg) and reasonable clearance (46.2 mL/min/kg). Also, pre-clinical efficacy studies of C57Bl/6 mice bearing Lewis Lung Carcinoma (LLC) xenografts demonstrated ∼80% tumor growth inhibition relative to vehicle control. Finally, micro-PET studies performed on mice bearing LLC tumors showed a significant inhibition of tumor 2-[18F]-fluoro-2-deoxy-glucose uptake. These studies demonstrate that PFK-015 is an effective inhibitor of PFKFB3, possesses compelling in vitro properties, has satisfactory PK properties in rodents, and suppresses tumor glucose metabolism and growth in an aggressive mouse model of non-small cell lung cancer. These results support further development of PFK-015 as a novel anti-cancer agent. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2825. doi:10.1158/1538-7445.AM2011-2825