New indolin-2-one and isoindoline-1,3-dione derivatives as potential anti-hepatocellular carcinoma agents targeting VEGFR-2: Synthesis, in vitro, in vivo, and in silico evaluation.

Vascular endothelial growth factor receptor-2 (VEGFR-2) is a pivotal therapeutic target in combatting tumor angiogenesis and hepatocellular carcinoma (HCC). In the current research, new indolin-2-one and isoindoline-1,3-dione derivatives were prepared as a part of lead optimization strategy, guided by the reported pharmacophoric features of type-II VEGFR-2 inhibitors. Biological evaluation over six human cancer cell lines identified compounds 5, 6a, 6b, 6e, and 6f as potent cytotoxic agents, exhibiting outstanding antiproliferative activity against HepG-2 liver cancer cells. Additionally, these most cytotoxic analogs showed low cytotoxicity against lung fibroblast (WI-38) and liver (L02) normal cells with excellent selectivity indices (SI) relative to HepG-2 cancer cells. In vivo anti-HCC assay for the most cytotoxic compound 6a demonstrated a reduction in liver weight comparable to sorafenib, and 6a-treated group presented lower serum level of AST and ALT compared to the untreated-HCC group. Histopathological examination demonstrated that 6a-treated group showed markedly high caspase-3 and low VEGF immunoreactivity. Cell cycle analysis indicated that compound 6a arrested HepG-2 cells at the G0/G1 phase, and induced cell death mainly through apoptosis that was verified by increased caspase-3 expression and elevated Bax/Bcl-2 ratio. VEGFR-2 inhibitory assay for the most active anticancer analogs revealed that 6f displayed promising inhibitory potency outperforming sorafenib, followed by compound 6a. Multikinase screening of the most potent VEGFR-2 inhibitors, compounds 6a and 6f, demonstrated appreciable inhibitory activity against the tested kinases, including EGFR, PDGFR-β and c-Met. Molecular docking studies confirmed that the engineered acylhydrazone scaffold of compounds 6a and 6f establishes essential hydrogen bonds with Glu885 and Asp1046 within the VEGFR-2 binding domain. Moreover, molecular dynamics simulations of compounds 6a and 6f reflected the typical binding mode of a well-optimized, high-affinity type II VEGFR-2 inhibitors. Compounds 6a and 6f may be considered as promising templates for subsequent optimization.