TBIO-01. SEX DIFFERENCES IN REDOX STATE UNDERLIE GLUTAMINE DEPENDENCY IN MALE GLIOBLASTOMA

Glioblastoma (GBM) is an aggressive brain tumor in children and adults. It occurs more commonly in males, but female patients survive significantly longer. Understanding the molecular mechanisms that underlie those sex differences could support novel treatment strategies. In this regard, we found that male and female GBM patient samples differ in their metabolite abundance and that males exhibit a significantly higher abundance of amino acid metabolites. We confirmed those findings in a murine model of GBM, which has previously yielded important insights into sexual dimorphism in GBM. Furthermore, we found that male GBM cell cultures are significantly more sensitive to amino acid deprivation, which was almost entirely driven by amino acids involved in the synthesis of the antioxidant glutathione. Glutaminase 1 (GLS1) mediates the conversion from glutamine to glutamate, a crucial component of glutathione. We found that male GBM cells exhibited higher levels of GLS1, suggesting they are more dependent on glutamate. Indeed, we found that male GBM cells are more sensitive to pharmacological GLS1 inhibition with the clinical inhibitor CB-839. This correlated with significantly increased reactive oxygen species (ROS) in males compared to females. We further confirmed sex differences in redox state through pharmacological depletion of glutathione that resulted in a significant increase in ROS and cell death in male GBM. Together, these data indicate that male GBM cells are more dependent on glutamine to regulate ROS levels. This reveals novel sex-specific metabolic targets for GBM and underlines the importance of considering sex in metabolic targeting approaches.