The In Vitro Cytotoxic Effect of Elesclomol on Breast Adenocarcinoma Cells Is Enhanced by Concurrent Treatment with Glycolytic Inhibitors

<b>Background/Objectives:</b> Glycolysis and mitochondrial oxidative phosphorylation are the two major metabolic pathways for cellular ATP production. The metabolic plasticity displayed by cancer cells allows them to effectively shift between each of these pathways as a means of adapting to various growth conditions, thus ensuring their survival, proliferation and disease progression. Metabolic plasticity also provides cancer cells with the ability to circumvent many traditional monotherapies aimed at only one or the other of the major ATP-producing pathways. The purpose of this study was to determine the effectiveness of a dual treatment strategy aimed simultaneously at both pathways of ATP production in human breast cancer cells. It was hypothesized that concurrent exposure of these cells to the mitochondria-targeting chemotherapeutic agent, elesclomol, in combination with either of two glycolytic inhibitors, 2-deoxy-D-glucose or 3-bromopyruvate, would yield greater in vitro anticancer effects than those observed for any of the compounds used as a single agent. <b>Methods:</b> Cytotoxicity and clonogenic assays were employed to assess the survival and proliferation of MCF7 and MDA-MB-231 human breast adenocarcinoma cells exposed to the compounds alone and in combination. <b>Results:</b> The data obtained show that the cancer-cell-killing and antiproliferative effects of the dual treatment were significantly enhanced compared to those observed for any of the compounds alone. <b>Conclusions:</b> The results of this study are important in that they suggest the possibility of a novel and effective chemotherapeutic strategy for breast cancer cell killing.