Does Valsartan Affect the Cytotoxicity of Doxorubicin When Used as a Cardioprotective Drug Against Doxorubicin-Induced Cardiotoxicity ?

Background: Doxorubicin is widely used as a chemotherapeutic drug. It has several serious side effects, including cardiotoxicity. Valsartan is an angiotensin II receptor blocker that plays a cardioprotective role against doxorubicin-induced cardiotoxicity. Aim: The aim of our study is to evaluate whether the combination of valsartan and doxorubicin affects the therapeutic efficacy of doxorubicin in treating cancer using an in vitro breast cancer cell line (MCF-7). Methods: Different concentrations of doxorubicin, valsartan, and their combination were tested to detect their cytotoxic effects on the cell line using MTT colorimetric assay method. Three duplicates of each concentration and control were made. Results: Valsartan had a mild cytotoxic effect only at higher concentrations, with an estimated IC50 value of 125.8 μg/ml, while doxorubicin, had more potent cytotoxicity, with an estimated IC50 value of 87.43 μg/ml. The IC50 of the doxorubicin-valsartan combination was lower than the IC50 of both drugs when used alone, with a DRI more than 1 (3.56) and an IAI less than 1 (0.94). Conclusions: There is synergism between doxorubicin and valsartan on MCF-7 breast cancer cells, suggesting a potential role for the combination in cancer treatment. The combination induces cytotoxicity in lower doses than when doxorubicin used alone.