The metabolic phenotypes associated with cancer offer great promise for therapeutic intervention, as tumor cells are believed to display dramatically different metabolic programs than non9transformed cells. Years of work have led to the development of a model in which oncogenic signaling rewires metabolic pathways in order to meet the biosynthetic demands of cell replication. It is important to note, however, that proliferation rates vary widely in tumors, and cells in most tumors are proliferating far slower than cells growing in culture. Nevertheless, over 80% of tumors display the elevated glucose uptake that is characteristic of unique tumor metabolism. This suggests that there may be proliferation9dependent and proliferation9independent aspects of tumor metabolism that we do not fully understand. My work has begun to address this question by investigating how metabolism changes as normal epithelial cells transition between proliferative and quiescent cell states. I have then applied this knowledge to cancer by performing a comprehensive bioinformatic analysis of how proliferation contributes to metabolic gene expression patterns in human tumors. This work has demonstrated the importance of proliferation in determining the cancer metabolic phenotype, and has also suggested that oncogenic signaling can also impact metabolism independent of proliferation. The experiments described in this proposal will further investigate how pro9growth signaling and proliferation interact to regulate cellular metabolism in normal and cancer cells, and will identify metabolic vulnerabilities in non9proliferating tumor cells—an area of significant clinical need due to their resistance to many traditional therapies. Aim 1 will elucidate proliferation9dependent and signaling9dependent aspects of cellular metabolism and will explore the importance of biosynthetic demands as a driver of the cancer metabolic phenotype. Aim 2 will identify unique metabolic programs in non9proliferating tumor cells—such as therapy resistant cells and cancer stem cells—that can be targeted to simultaneously kill proliferating and non9proliferating cancer cells. And Aim 3 will explore glucose metabolism as a proliferation9independent aspect of tumor metabolism that forces metabolic adaptations in non9proliferating cancer cells, thereby creating unique metabolic vulnerabilities. Together, these studies will advance our understanding of how and why cancer cells are metabolically different from normal cells, and will hasten progress towards successfully targeting cancer metabolism in the clinic by identifying truly unique aspects of the metabolism of cancer cells.