Reprogramming of metabolic pathways, a hallmark of human cancer, results from a process in which cancer cells become dependent on specific metabolic pathways such as glutamine catabolism or glutaminolysis for growth and survival. Previous studies have demonstrated that triplenegative breast cancers (TNBC) may use glutamine as an extracellular nutrient source to generate lipids, proteins, and nucleic acids. Glutamine catabolism in cancer cells also contributes to the production of the antioxidant, glutathione (GSH), which is critical for redox homeostasis and for protection of cells from oxidative stress elicited by reactive oxygen species (ROS). Considering TNBC cell lines are often dependent on glutamine for growth and survival, we sought to determine whether targeting glutaminolysis with a small molecule inhibitor, CB-839, in combination with platinum-based chemotherapy drug, would elicit significant anti-tumor activity.