TAMI-19. METABOLIC INTERACTIONS BETWEEN TUMOR CELLS AND THE IMMUNE SYSTEM IN GBM: A POTENTIAL ACHILLES HEEL OF GBM FOR NOVEL THERAPEUTICS

Abstract

Abstract INTRODUCTION Glioblastoma (GBM) contains cell populations with distinct metabolic requirements, with fast-cycling cells harnessing aerobic glycolysis, and treatment-resistant slow-cycling cells (SCCs) preferentially engaging lipid metabolism. How the different tumor cells interact with immune cells and how this metabolic heterogeneity shapes the immune landscape in GBM has yet to be understood. OBJECTIVES The objectives are to unravel the various molecular signals and metabolic link that underlie the interaction of SCCs with the GBM microenvironment, in particular with the suppressive immune compartment, and to effectively target these interactions for better therapeutics. METHODS Multiple murine glioma cell lines were used to establish metabolic heterogeneity and communications, while various genetic and pharmacological approaches were applied to assess the effect of disrupting the metabolic interplay between SCCs and the immune system. RESULTS We determined that SCCs exhibit distinct metabolic dependencies, involving preferential lipid metabolism supported by enhanced fatty acid uptake. We also found that tumor progression is regulated by the interaction of SCCs with the immune system and established that SCCs recruit immune suppressive M2-like macrophages to the tumor microenvironment, which in turn work against tumor immune rejection by inhibiting T cell anti-tumor activity. The immune microenvironment shaped by SCCs is marked by specific metabolic features enhancing lipid exchange capacities that are exploited by SCCs to support their survival and functions. Importantly, disrupting lipid metabolic exchange sensitized tumors to chemotherapy. CONCLUSION Our results reveal that metabolic interactions between SCCs and tumor-associated macrophages within the GBM microenvironment play a critical role in the development of drug and immune resistant tumors. This study delineates these metabolic communications and assesses the potential therapeutic effect of disrupting these interactions to treat GBM. The insights generated from this project uncover fundamental principles of the emerging connections between the tumor microenvironment, cell metabolism, anti-tumor immunity, and associated therapeutic vulnerabilities.