Targeting Metabolic Reprogramming to Improve Breast Cancer Treatment: An In Vitro Evaluation of Selected Metabolic Inhibitors Using a Metabolomic Approach

Characteristic metabolic adaptations are recognized as a cancer hallmark. Breast cancer, like other cancer types, displays cellular respiratory switches—in particular, the Warburg effect—and important fluctuations in the glutamine and choline metabolisms. This cancer remains a world health issue mainly due to the side effects associated with chemotherapy, which force a reduction in the administered dose or even a complete discontinuation of the treatment. For example, Doxorubicin is efficient to treat breast cancer but unfortunately induces severe cardiotoxicity. In the present in vitro study, selected metabolic inhibitors were evaluated alone or in combination as potential treatments against breast cancer. In addition, the same inhibitors were used to possibly potentiate the effects of Doxorubicin. As a result, the combination of CB-839 (glutaminase inhibitor) and Oxamate (lactate dehydrogenase inhibitor) and the combination of CB-839/Oxamate/D609 (a phosphatidylcholine-specific phospholipase C inhibitor) caused significant cell mortality in both MDA-MB-231 and MCF-7, two breast cancer cell lines. Furthermore, all inhibitors were able to improve the efficacy of Doxorubicin on the same cell lines. Those findings are quite encouraging with respect to the clinical goal of reducing the exposure of patients to Doxorubicin and, subsequently, the severity of the associated cardiotoxicity, while keeping the same treatment efficacy.