Design, synthesis of novel chromene-based scaffolds targeting hepatocellular carcinoma: Cell cycle arrest, cytotoxic effect against resistant cancer cells, apoptosis induction, and c-Src inhibition.

New chromene derivatives were synthesized based on 4-(3,4-dimethoxy)-4H-chromene scaffold. All target compounds exhibited cytotoxic activity against HepG2 cells (IC  = 2.40-141.22 μM). Chromens 5 and 9 showed superior cytotoxicity over staurosporine (IC  = 18.27 μM) and vinblastine (IC  = 5.20 μM). c-Src kinase inhibition assay of compounds 5 and 9 displayed the dominant c-Src inhibitory activity of 5 (IC  = 0.184 μM) over 9 (IC  = 0.288 μM). The safety of the most potent compound 5 against normal WI-38 cells was confirmed via its IC of 115.75 μM comparable with 5-FU (IC  = 16.28 μM). Moreover, the promising chromene 5 displayed potent cytotoxicity against resistant HepG2 cells with IC of 26.03 μM comparable with 5-FU (IC  = 42.68 μM). The most active chromene 5 arrested the HepG2 cell cycle at the S phase and induced a 29-fold increase in the total number of apoptotic cells indicating pre-G1 apoptosis. The ability of compound 5 to induce apoptosis was supported via elevation of caspase-3, caspase-7, caspase-9 and proapoptotic Bax protein levels in addition to downregulation of the antiapoptotic Bcl2 protein. Molecular docking studies of compound 5 showed good binding interaction pattern inside c-Src kinase enzyme active site.