A series of 3-benzylideneindolin-2-one compounds was designed and synthesized based on combretastatin A-4 and compound IC261, a dual casein kinase (CK1)/tubulin polymerization inhibitor, taking into consideration the pharmacophore required for EGFR-tyrosine kinase inhibition. The new molecular entities provoked significant growth inhibition against PC-3, MCF-7 and COLO-205 at a 10 μM dose. Compounds 6-chloro-3-(2,4,6-trimethoxybenzylidene) indolin-2-one, 4b, and 5-methoxy-3-(2,4,6-trimethoxybenzylidene)indolin-2-one, 4e, showed potent activity against the colon cancer COLO-205 cell line with an IC₅₀ value of 0.2 and 0.3 μM. A mechanistic study demonstrated 4b’s efficacy in inhibiting microtubule assembly (IC₅₀ = 1.66 ± 0.08 μM) with potential binding to the colchicine binding site (docking study). With an IC₅₀ of 1.92 ± 0.09 μg/mL, 4b inhibited CK1 almost as well as IC261. Additionally, 4b and 4e were effective inhibitors of EGFR-TK with IC₅₀s of 0.19 μg/mL and 0.40 μg/mL compared to Gifitinib (IC₅₀ = 0.05 μg/mL). Apoptosis was induced in COLO-205 cells treated with 4b, with apoptotic markers dysregulated. Caspase 3 levels were elevated to more than three-fold, while Cytochrome C levels were doubled. The cell cycle was arrested in the pre-G1 phase with extensive cellular accumulation in the pre-G1 phase, confirming apoptosis induction. Levels of cell cycle regulating proteins BAX and Bcl-2 were also defective. The binding interaction patterns of these compounds at the colchicine binding site of tubulin and the Gifitinib binding site of EGFR were verified by molecular docking, which adequately matched the reported experimental result. Hence, 4b and 4e are considered promising potent multitarget agents against colon cancer that require optimization.

Background: Sulfonamide acridine derivatives have garnered significant attention from medicinal chemists due to their diverse range of biological activities. Methods: In this study, eleven compounds were synthesized according to the literature, and their impact on cell growth inhibition, induction of apoptosis, and cell cycle distribution were assessed in three different cell lines. Their inhibitory effects on the topoisomerase (Topo) I and II were investigated in vitro. Molecular docking studies were conducted to predict the binding affinities of these compounds for crystallized downloaded topoisomerases. Results: The compounds were examined in vitro for their anticancer activity against human hepatic (HepG2) colon (HCT-8) and breast (MCF-7) carcinoma cell lines. Compound 8b was the most active against HepG2, HCT-116, and MCF-7 with IC₅₀ 14.51, 9.39, and 8.83 µM, respectively, compared to Doxorubicin as reference. In addition, it demonstrated the highest potency among the tested compounds against Topo-I, with an IC₅₀ value of 3.41 µg/mL compared to the control camptothecin (IC₅₀ of 1.46 μM). Compound 7c displayed a significant inhibitory effect on Topo-II, with an IC₅₀ of 7.33 μM, compared to an IC₅₀ value of 6.49 μM via Doxorubicin, the control. Compounds 7c and 8b were assessed against topoisomerases showing induction of apoptosis and a reduction in the S phase of the cell cycle. Molecular docking demonstrated interaction with the active site as with those exhibited by the co-crystallized ligands of the crystallized proteins in both topoisomerases. Conclusion: Compounds 7c and 8b hold promise as potential anticancer drugs due to their anti-proliferative and proapoptotic effects, which are mediated by their action on the topoisomerase enzyme, particularly Topo II.