Evaluation the Effect of Renin-Angiotensin System Antagonists on the Cytotoxicity of Doxorubicin against MDA-MB-231 and MCF-7 Cell Lines

Aim:: The renin-angiotensin system (RAS) is an endocrine system essential for regulating blood pressure and fluid balance. Components of this system are expressed not only in various body cells but also in breast cancer cells. Angiotensin-converting enzyme (ACE) inhibitors, which are widely used as antihypertensive agents, have been proposed to have an additional benefit in reducing the risk of certain cancers. Doxorubicin is a commonly used chemotherapy drug, also employed in the treatment of breast cancer. One of the side effects of doxorubicin is its toxicity to cardiac cells. This research aims to investigate the effect of cytotoxicity of four RAS antagonists (enalapril, captopril, valsartan, and losartan) in the presence and absence of doxorubicin against two breast cancer cell lines including MCF-7 and MDA-MB-231. The study’s objective is to determine whether these RAS inhibitors can modulate the cytotoxicity of doxorubicin and their potential impact on breast cancer cell survival.Material and methods: MTT is one of the colorimetric methods to investigate cell survival. This assay is based on the conversion of the MTT reagent to a formazan product by metabolically active cells, providing a quantitative measure of cell viability. The effect of RAS inhibitors in the presence and absence of doxorubicin on the survival of cancer cells was measured using the MTT test. Chemotherapy drugs, such as doxorubicin, typically reduce cell survival by inducing apoptosis. One of the markers of apoptosis induction in cells is the evaluation of caspase-3/7 activity. The induction of apoptosis in MDA-MB-231 cells treated with the RAS inhibitors was investigated using a caspase-3/7 activity assay kit, which quantifies the enzymatic activity in cell lysates. Results: Enalapril had no significant cytotoxic effect on breast cancer cells at concentrations up to 500 μg/mL. Captopril and losartan were toxic to breast cancer cells. Valsartan had no cytotoxic effect on breast cancer cells and increased cell proliferation over time. The cytotoxic effects of captopril and losartan on breast cancer cells may be attributed to their inhibitory effects on the RAS. The RAS plays a crucial role in regulating blood pressure and fluid balance, but it also has inhibitory effects on tumor growth and progression. By blocking the activity of the RAS with captopril and losartan, the cells may experience reduced proliferation and ultimately cytotoxicity. Enalapril, captopril, valsartan, and losartan protected breast cancer cells from doxorubicin cytotoxicity in a concentration- and time-dependent manner. Captopril and losartan treatment increased caspase-7/3 activity in MDA-MB-231 cells. The increase in caspase-7/3 activity in MDA-MB-231 cells suggests that captopril and losartan-induced cytotoxicity may be accompanied by apoptosis. Apoptosis is a desirable outcome in cancer treatment as it allows for the elimination of cancer cells while preserving normal tissue function.Conclusion: RAS inhibitors can interfere with the cytotoxic effects of doxorubicin on breast cancer cells, depending on the concentration and duration of exposure. Further research is required to understand the optimal use and dosage of RAS system inhibitors in this context to ensure a balance between protecting the heart from doxorubicin-induced cardiotoxicity and maintaining the efficacy of cancer treatment.