Abstract B27: Kras alters expression of asparagine synthetase (Asns) in non-small cell lung cancer (NSCLC) and protects tumors during nutrient stress

Abstract

Abstract Kras is a small GTPase that functions in the transmission of extracellular mitogenic stimuli, and is one of the most frequently mutated genes in non-small cell lung cancer (NSCLC). Previously, Kras has been demonstrated to play a role in tumor metabolism in certain cell types and cancers, but this has yet to be analyzed in the context of NSCLC. We have analyzed how Kras changes metabolic gene expression by expressing a doxycycline-inducible hairpin against Kras in 4 NSCLC cell lines. One of the most regulated metabolism genes is asparagine synthetase (Asns), which transfers the γ-amino group of glutamine to aspartate, yielding glutamate and asparagine. We find elevated levels of Asns in Kras mutant tumors, and that expression of Asns correlates with poor patient outcome. Knockdown of Asns in the absence of exogenous asparagine in the media results in inhibition of cell growth and induction of apoptosis that is rescued by addition of asparagine. Additionally, under conditions of low glutamine levels, knockdown of Asns sensitizes cells to apoptosis, and overexpression of Asns is protective under these conditions. We also find a role for the glutaminase-activity of Asns in glutamine-mediated anapleurosis of the TCA cycle. These observations suggest Asns may be an interesting therapeutic target for NSCLC tumors with mutations in Kras. Citation Format: Dana M. Gwinn, Alejandro Sweet-Cordero. Kras alters expression of asparagine synthetase (Asns) in non-small cell lung cancer (NSCLC) and protects tumors during nutrient stress. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr B27.