Project Summary/Abstract Cancers display altered cellular metabolism compared to the normal tissues from which they arise. One promising therapeutic approach is to take advantage of these differences by designing interventions that target the metabolic requirements of cancer cells. We have observed that maintaining aspartate levels is critical for cancer cell proliferation by supporting the synthesis of the nucleotides and protein needed for proliferation. Our work in tumor models has also indicated that intracellular aspartate is an endogenous metabolic limitation of tumor growth. Aspartate is relatively impermeable to cells and must be synthesized from other metabolic precursors. Thus, inhibiting the mechanisms cancer cells use to maintain aspartate levels is a potential method of treating cancer. This proposal uses several approaches to target aspartate levels and determine the cancers in which aspartate is most limiting. Specifically, we will determine the conditions in which aspartate is an endogenous metabolic limitation for tumors (Aim 1), investigate if reductive glutamine metabolism supports aspartate production in hypoxic cells (Aim 2), and test if altering asparagine synthesis can affect aspartate levels and cancer cell proliferation (Aim 3). We will use cell culture to test the mechanistic elements of these hypotheses and use preclinical mouse models of cancer to determine their efficacy in vivo. Together, these studies will investigate new therapeutic methods to target the metabolism of cancer cells and to identify the situations in which they are best deployed. The long-term scientific goal of this project is therefore to improve cancer therapy by identifying new therapeutic targets and validating them in mouse models of cancer.