Enhanced therapeutic efficacy of doxorubicin/cyclophosphamide in combination with pitavastatin or simvastatin against breast cancer cells

Fighting breast tumors mandates finding different agents devoid of chemotherapy side effects. Repurposing existing drugs, such as statins, presents a promising avenue for the development of novel cancer therapeutics. Based on the different effects of statin members, this study aims to evaluate the effect of two of the most promising lipophilic statins, Simvastatin and Pitavastatin, and their combination with a conventional chemotherapeutic regimen of doxorubicin and cyclophosphamide on breast cancer cells. MDA-MB-231 and MCF7 cell lines were used to analyze the effects of Pitavastatin and simvastatin in combination with doxorubicin/cyclophosphamide. Cell viability and cell cycle were analyzed and certain apoptosis-related genes such as Bax, Bcl2, and caspase-3, besides cyclin D1 were analyzed using qPCR. The viability of breast cancer cells decreased significantly after treatment with a doxorubicin/cyclophosphamide combination in the presence of Pitavastatin or simvastatin compared with dual doxorubicin/cyclophosphamide with a higher effect in MDA-MB-231 cells than MCF7. In MDA-MB-231, The triple combination of Pitavastatin or simvastatin with doxorubicin/cyclophosphamide resulted in an increase in the expression levels of apoptotic markers than treatment with doxorubicin/cyclophosphamide combination (Bax (p-value = 0.09& 0.02, respectively), Bax/Bcl2 ratio (p-value = 0.0002& <0.0001, respectively)). However, the increase in caspase3 wasn't significant (p-value = 0.45& 0.09, respectively). Moreover, the expression of cyclin D1 decreased (p-value = 0.0002& <0.0001, respectively) and the cell cycle was arrested in the G1 phase. Combination of Pitavastatin or simvastatin with doxorubicin/ cyclophosphamide may induce apoptosis in breast cancer cells via upregulation of the Bax/Bcl2 pathway, potentially providing a promising new therapeutic strategy for breast cancer.