Novel VEGFR2 inhibitors with thiazoloquinoxaline scaffold targeting hepatocellular carcinoma with lower cardiotoxic impact

Hepatocellular carcinoma (HCC) is a fatal tumor which is usually diagnosed at advanced stage. Molecular targeted drugs were used recently to treat HCC, however, due to serious side effects, mainly cardiotoxicity and emergence of resistance, there is demanding to explore new chemotherapeutics. 10 novel thiazoloquinoxaline derivatives coupled with different sulfonamide moieties 4(a-j) were designed and synthesized fulfilling pharmacophoric features of VEGFR-2 inhibition. Structures of all new compounds were verified via spectral and microanalytical data. After carrying in-vitro VEGFR-2 assay for compounds 4(a-j); sulfapyridine and sulfamethoxazole derivatives 4d and 4f showed potential inhibitory effect [61.04 and 83.35 nM], respectively, comparable to standard sorafenib [51.41 nM]. Both were then further evaluated for their cytocidal activity against HepG2 cell-line and against myocardium cells using H9C2 cell-line. As a result, only sulfapyridine derivative 4d exhibited a significant inhibition of HepG2 cells viability [IC₅₀ = 4.31 μM]. Furthermore, it showed relatively lower cytotoxic impact against normal H9C2 myocardium cells [IC₅₀, 33.47 μM] compared to that of sorafenib [IC₅₀, 98.07 μM]. In-vivo study was carried out to determine myocardium safety of compound 4d on irradiated mice (8 Gy). In-vivo results of sulfapyridine derivative 4d showed normal cardiac Enzyme function (CK) and serum catalase activity with significant reductions in LDH, cardiac TNF-α and caspase-9 levels, alongside with its efficacy in suppressing the expression of hepatic VEGF. In conclusion, sulfapyridine derivative 4d could be considered a promising candidate as VEGFR-2 inhibitor with less myocardium side effect.