Unravelling the cardioprotective effects of calcitriol in Sunitinib-induced toxicity: A comprehensive in silico and in vitro study.

Sunitinib (SUN), a drug used to treat advanced renal cell carcinoma and other cancers, causes cardiotoxicity. This study aimed to identify a potential drug candidate to counteract SUN-induced cardiotoxicity. We analysed real-world data from adverse event report databases of existing clinically approved drugs to identify potential candidates. Through in silico analyses and in vitro experiments, the mechanisms of action were determined. The study identified calcitriol (CTL), an active form of vitamin D, as a promising candidate against SUN-induced cardiotoxicity. In H9c2 cells, SUN decreased cell viability significantly, whereas CTL mitigated this effect significantly. The SUN-treated group exhibited increased autophagy in H9c2 cells, which was reduced significantly in the CTL group. Bioinformatics analysis using Ingenuity Pathway Analysis revealed the mechanistic target of rapamycin (mTOR) as a common factor between autophagy and CTL. Notably, rapamycin, an mTOR inhibitor, nullified the effects of CTL on cell viability and autophagy. Furthermore, SUN treatment led to significant reductions in cardiomyocyte diameters and increases in their widths, changes that were inhibited by CTL. SUN also induced morphological changes in surviving H9c2 cells, causing them to adopt a rounded shape, whereas CTL improved their morphology to resemble the elongated shape of the control group. In conclusion, the findings of the present study suggest that CTL has the potential to prevent SUN-induced cardiomyocyte damage through autophagy, particularly via mTOR-mediated pathways. The findings indicate that CTL could serve as an effective prophylactic agent against SUN-induced cardiotoxicity, offering a promising avenue for further research and potential clinical applications.