Abstract 461: Targeting glucose metabolism in lung cancer

Abstract

Abstract Positron emission tomographic studies with 2-18F-fluoro-deoxy-glucose (FDG-PET) consistently demonstrate that non-small cell lung cancers (NSCLC) take up significantly more glucose than normal lung. NSCLCs preferentially utilize glucose to support their rapid growth- a phenotype driven by several oncogenic alterations among which mutations of the oncoprotein Ras are frequently observed. Oncogenic Ras is shown to activate downstream effectors (e.g. HIF-1α) that stimulate glycolysis - in part by activation of the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase family of enzymes (PFKFB1-4). The PFKFBs produce fructose-2,6-bisphosphate (F26BP) which activates a key rate-limiting glycolytic enzyme, 6-phosphofructo-1-kinase (PFK1). In preliminary studies, we found that the PFKFB4 family member was highly expressed relative to other PFKFB isoforms (by multiplex RT-PCR) in a series of patient-derived NSCLCs relative to paired normal lung tissue. We further explored PFKFB4 protein expression by immunohistochemistry in NSCLCs derived from a cohort of patients and found markedly elevated PFKFB4 in the majority of tumors relative to adjacent normal tissue. We then determined that silencing PFKFB4 markedly reduced F26BP, glycolysis and cell survival in NSCLC cell lines and inhibited xenograft lung tumor growth in vivo. In order to target PFKFB4, we conducted a virtual screen of compounds that fit into the active site of PFKFB4 and discovered a first-in-class small molecule selective PFKFB4 inhibitor, termed 5MPN, that selectively inhibits recombinant PFKFB4 activity and decreases F26BP, glycolysis and proliferation in multiple NSCLC cell lines, with significantly higher anti-proliferative effects in Ras-driven cell lines. 5MPN also caused marked suppression of growth in established NSCLC xenograft tumors, importantly without systemic toxicity. We have developed an inducible, pan-tissue homozygous floxed Pfkfb4 knockout mouse and crossed it with a Cre recombinase mouse driven by a tamoxifen-inducible β-actin promoter to produce Cre/Pfkfb4fl/fl mice. We crossed Cre/Pfkfb4fl/fl mice with a Ras-driven lung cancer model, induced Pfkfb4 deletion by tamoxifen administration and found significantly lower total lung tumor burden in these mice accompanied by decreased PFKFB4 expression in tumors and lung tissue. Taken together, these data provide strong rationale for the further evaluation of small molecule inhibitors of PFKFB4 as a potential therapeutic strategy against NSCLC. Citation Format: Sucheta Telang, Simone Chang, Nicole Sanders. Targeting glucose metabolism in lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 461.