Abstract B39: Asparagine drives translational adaptation of cancer cells to glutamine deficit

Abstract Most proliferating cells consume exogenous glutamine to fuel biosynthesis and cell growth, which leads to its marked depletion from the microenvironment. Glutamine provides carbon and nitrogen for a wide array of biomolecules, among which are non-essential amino acids, glucosamine and nucleotides; in addition, carbon backbone of glutamine is used as a preferred anaplerotic input into the TCA cycle. However, as recent in vivo metabolomic studies indicate, a number of tumor types are capable of utilizing alternative anaplerotic routes and, in fact, synthesize glutamine de novo. In addition, select cancer cell lines are able to proliferate in the absence of exogenous glutamine in culture medium. However, the metabolic and regulatory underpinnings that enable the cellular adaptation to glutamine deficit and de novo glutamine production need further investigation. In this work, we identified the non-essential amino acid asparagine as essential for the survival and proliferation of cancer cells in the absence of exogenous glutamine supply. Our data indicate that asparagine, though structurally related to glutamine, is not catabolized in the same manner. Instead, asparagine acts by restoring protein translation, which becomes profoundly compromised in the absence of glutamine. This, in turn, enables the post-transcriptional adaptive upregulation of glutamine synthetase (GLUL), which is required for glutamine-independent growth. Taken together, these findings show that the cellular adaptation to glutamine-limiting conditions relies upon the availability of asparagine, which may represent an important therapeutic vulnerability. Citation Format: Natalya N. Pavlova, Ji Zhang, Craig B. Thompson. Asparagine drives translational adaptation of cancer cells to glutamine deficit. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B39.