Targeting Metabolic Remodeling in Triple Negative Breast Cancer in a Murine Model

Abstract

Background: Chemotherapy is the backbone of systemic treatment for triple negative breast cancer (TNBC), which is one of the most relevant breast cancers molecular types due to the ability of tumor cells to develop drug resistance, highlighting the urgent need to design newer and safer drug combinations for treatment. In this context, to overcome tumor cell drug resistance, we employed a novel combinatorial treatment including Doxorubicin, Metformin, and Sodium Oxamate (DoxMetOx). Such pharmacological combination targets indispensable hallmarks of cancer-related to aerobic glycolysis and DNA synthesis.Materials and Methods: Thirty-five female nude mice were transplanted subcutaneously with MDA-MB-231 triple negative human cancer cell line. Once tumors were visible, mice were treated with doxorubicin, metformin, oxamate or all possible pharmacologic combinations. Treatments were administered daily for 15 days and tumors were measured by calipers every day. MicroPET images were taken in three different occasions, basal state, in the middle of the treatment, and at the end of treatment. Western blot analyses, qRT-PCR, flow cytometry, and cytotoxicity assays were performed to elucidate the mechanism of cell death promoted by the drugs in vitro.Results: In this work we assessed the proof of concept of metabolic correction in solid tumors as an effective drug treatment; hence, mice bearing tumors treated with the DoxMetOx therapy showed a complete inhibition of the tumor mass growing in 15 days of treatment depicted by the micro PET images. In vitro studies displayed that the three drugs together act by inhibiting both, mTOR-phosphorylation and expression of LDH-A gene, promoting apoptosis via dependent on the caspase-3 pathway, accompanied by cleavage of PARP. Moreover, induction of autophagy process was observed by the accumulation of LC3-II, a primordial protein implicated in the conformation and elongation of the autophagolysosome.Conclusions: The lack of effective drugs to inhibit TNBC growth is the main cause of therapy failure and tumor relapse. We have showed that targeting crucial molecular pathways in cancer by the combination of Doxorubicin, Metformin, and Oxamate resulted as an efficient and rapid tumor growth inhibitor in a triple negative xenograft model. Our findings are promising for patients diagnosed with TNBC tumors, for which unfortunately there are no reliable drug therapies.

Stress-induced epinephrine enhances lactate dehydrogenase A and promotes breast cancer stem-like cells

“…The LDHA inhibitor sodium oxamate is known to be an effective anticancer agent in many types of cancer, including breast (53–56), non–small cell lung (57), and gastric cancer (58). However, the clinical application of sodium oxamate has been limited because of its high therapeutic doses and relatively low potency (59–61).…”

Metabolic Reprogramming in Breast Cancer and Its Therapeutic Implications

“…Other regimens include combinations of adriamycin-taxane-cyclophosphamide, and 5-fluorouracil-epirubicin-cyclophosphamide followed by taxanes [261]. Combining doxorubicin with metabolic inhibitors such as metformin and sodium oxamate maximized tumor growth inhibition as compared to any bi-drug combination [262]. The expression of transketolase (TKT), a metabolic enzyme involved in the non-oxidative branch of the PPP also linking it to glycolysis, was found to correlate with tumor size in a syngeneic TNBC murine model.…”

Online 1H‐MRS measurements of time‐varying lactate production in an animal model of glioma during administration of an anti‐tumoral drug

“…As a proof‐of‐concept of this approach, we investigated the impact of oxamate on the extracellular lactate concentration. As a result of its competitive inhibitory effect on lactate dehydrogenase A (LDH‐A), the enzyme converting pyruvate to lactate, oxamate is considered as a potential anti‐tumor molecule and has been investigated in vitro and in vivo in animal models of cancer . The impact of oxamate on cell viability was assessed in vitro and, depending on the tumor cell line, the 50% inhibitory concentration ranged between 20 and 58mM at 24 h .…”

“…As a result of its competitive inhibitory effect on lactate dehydrogenase A (LDH‐A), the enzyme converting pyruvate to lactate, oxamate is considered as a potential anti‐tumor molecule and has been investigated in vitro and in vivo in animal models of cancer . The impact of oxamate on cell viability was assessed in vitro and, depending on the tumor cell line, the 50% inhibitory concentration ranged between 20 and 58mM at 24 h . As a reminder, in our study, the oxamate concentration in the perfusate was equal to 5mM and the perfusion time was less than 1 h. Despite this short period and limited exposure to oxamate, a marked decrease in lactate concentration was observed shortly after the administration of oxamate, providing an objective measure of the immediate and potent inhibitory effect of this molecule on lactate production and excretion.…”