Exploring the repurposing potential of telmisartan drug in breast cancer: an in-silico and in-vitro approach

Anticancer drug resistance is one of the biggest hurdles in the treatment of breast cancer. Drug repurposing is a viable option fordeveloping novel medical treatment strategies since this method is more cost-efficient and rapid. Antihypertensive medicines have recently been found to have pharmacological features that could be used to treat cancer, making them effective candidates for therapeutic repurposing. The goal of our research is to find a potent antihypertensive drug that can be repurposed as adjuvant therapy for breast cancer. In this study, virtual screening was performed using a set of Food and Drug Administration (FDA)-approved antihypertensive drugs as ligands with selected receptor proteins (EGFR, KRAS, P53, AGTR1, AGTR2, and ACE) assuming these proteins are regarded to have a significant role in hypertension as well as breast cancer. Further, our in-silico results were further confirmed by an in-vitro experiment (cytotoxicity assay). All the compounds (enalapril, atenolol, acebutolol, propranolol, amlodipine, verapamil, doxazosin, prazosin, hydralazine, irbesartan, telmisartan, candesartan, and aliskiren) showed remarkable affinity towards the target receptor proteins. However, maximum affinity was displayed by telmisartan. Cell-based cytotoxicity study of telmisartan in MCF7 (breast cancer cell line) confirmed the anticancer effect of telmisartan. IC50 of the drug was calculated to be 7.75 µM and at this concentration, remarkable morphological alterations were observed in the MCF7 cells confirming its cytotoxicity in breast cancer cells. Based on both in-silico and in-vitro studies, we can conclude that telmisartan appears to be a promising drug repurposing candidate for the therapeutic treatment of breast cancer.