In silico and in vitro evaluation of new sulfonamide derivatives as VEGFR-2 inhibitors for cancer therapy

Vascular endothelial growth factor receptor 2 (VEGFR-2) is a principal regulator of tumor progression and angiogenesis, which makes it an attractive target for developing and creating anticancer agents. A series of sulfonamide-derived compounds (K1-K5) were designed and evaluated for their ability to inhibit VEGFR-2 and for their cytotoxic activity against HCT-116 (colon), HepG-2 (liver), MCF-7 (breast) human cancer cells, and WI-38 (normal) fibroblasts. All of the compounds produced significant inhibition of VEGFR-2, with IC50values ranging from 0.0917 ± 0.028 µM (K5) to 1.2007 ± 0.013 µM (K1), relative to Sorafenib (IC50 = 0.0525 ± 0.017 µM). The most promising compound was K4, which produced potent inhibition of VEGFR-2 (IC50 = 0.1717 ± 0.027) and the highest selectivity index (SI) of all tested compounds: 25.6 (HCT-116), 14.8 (HepG-2), and 17.0 (MCF-7). In contrast to Sorafenib, whose Selectivity Index (SI) values range between 2.1 and 4.9, the SI values of both Vinblastine and Doxorubicin are less than 2.0 across these particular cell lines. This suggests that K4 has 12 times greater selectivity than Sorafenib and over 25 times greater selectivity than traditional chemotherapeutics. The increased selectivity of K4 can be attributed to the incorporation of a urea-linked sulfonamide moiety, which allows for the formation of hydrogen bonds and minimizes nonspecific hydrophobic interactions. Collectively, these data will demonstrate the importance of designing sulfonamide analogues with optimal structural characteristics to identify effective and specific VEGFR-2 inhibitors and that K4 represents a potentially important candidate for continued preclinical development.