LDH and TGF-β pathway blockade prevents mammary tumor metastasis altogether in SD rats

The present study reports the combined inhibition of lactate dehydrogenase (LDHA) and transforming growth factor-β (TGF-β) with Sodium oxamate and A-8301 combination therapy. Previous studies have reported that hypoxia-induced lactic acidosis plays a pivotal role in acquiring the most aggressive metastatic behavior in solid benign tumors of the mammary gland. Furthermore, Lactic acidosis in the TME activates various cytokines like transforming growth factor-β (TGF-β), which enhances the gene expression of VEGF, MMP9 and vimentin, required for the metastatic progression of Breast Cancer. With this hypothesis in mind, sodium oxamate was selected as the inhibitor of LDHA (to prevent lactic acidosis), and A-8301 was selected as the inhibitor of the TGF-β1 receptor and explored against 7,12-dimethylbenzanthracene (DMBA) induced mammary gland carcinoma in female SD rats. To evaluate the effect of combination therapy, experimental animals were subjected to weight variation analysis, tumor size and tumor burden, effect on serum biochemicals such as SGOT, SGPT, creatinine and LDH, were studied. Microscopic techniques like carmine staining and histopathology were performed to evaluate the anti-angiogenic and protective role of therapy at the tissue level. Immunohistochemistry of breast tissue was performed to explore the effect at the molecular level. Results of weight variations and biochemical parameters evidenced that combination therapy worked well to prevent weight loss and to restore the biochemical parameters. Findings of the immunohistochemistry evidenced a significant decrease in the levels of HIF-1alpha, LDHA, TGF-beta, VEGF, MMP and vimentin in the treated groups compared to the toxic control, which further validated the efficacy of the combination therapy against metastatic transformation of mammary gland carcinoma. Conclusively, combination therapy of sodium oxamate with A-8301 has the potential to prevent the metastatic progression of breast cancer.