p53 promotes cancer cell adaptation to glutamine deprivation by upregulating Slc7a3 to increase arginine uptake

Cancer cells heavily depend on the amino acid, glutamine, to meet the demands associated with growth and proliferation. Due to its rapid consumption, cancer cells frequently undergo glutamine starvation in vivo. We and others have shown that p53 is a critical regulator in metabolic stress resistance. To better understand the molecular mechanisms by which p53 activation promotes cancer cell adaptation to glutamine deprivation, we identified p53-dependent genes that are induced upon glutamine deprivation using RNA-seq analysis. We show that Slc7a3, an arginine transporter, is significantly induced by p53. We show the concomitant rise in intracellular arginine levels following glutamine deprivation is dependent on p53. The influx of arginine has minimal effect on known metabolic pathways upon glutamine deprivation. Instead, we found arginine serves as an effector for mTORC1 activation to promote in vitro and in vivo cell growth in response to glutamine starvation. Therefore, we identify a novel p53-inducible gene that contributes to the metabolic stress response. Overall design: mRNA profiles of p53-expressing and non-expressing MEF cell lines cultured in the presence or absence of glutamine