Fragment merging design, synthesis, and biological evaluation of novel methyl Selanyl– And thiazolidinedione-based hybrids as potent anticancer inducing apoptosis and cell cycle arrest

AbstractA novel series of methyl selanyl– and 2,4-thiazolidinedione–based hybrids (HB68–HB167) was rationally designed using a fragment-merging strategy, in which key pharmacophoric elements were combined to generate structurally integrated hybrid molecules with enhanced anticancer potential. The synthesized compounds were evaluated for anticancer activity using the sulforhodamine B (SRB) assay against seven human cancer cell lines—A549, H460, HuH7, MCF7, HCT116, MG63, and PC3—alongside the non-malignant human skin fibroblast (HSF) cell line. Most compounds exhibited strong cytotoxicity toward cancer cells with limited toxicity to HSF (mean GI% = 43.48%). Notably, HB73, HB118, HB147, HB68, and HB128 achieved the highest mean GI% values (77.62, 76.58, 76.33, 70.90, and 70.70%, respectively), all surpassing doxorubicin (DOX) (68.07%). These findings indicate that high activity can be achieved with or without the 2,4-thiazolidinedione moiety and that phenyl acetamido and benzyl groups are privileged substituents. IC₅₀ assessment confirmed potent cytotoxicity: HB167 (PC3, 8.43 μM, where DOX, 8.41 μM), HB147 (MCF7, 8.64 μM < DOX, 10.74 μM; HCT116, 13.99 μM, where DOX, 10.46 μM). Protein expression analysis in HCT116 cells showed that HB68 and HB147 upregulated pro-apoptotic markers (BAX, Caspases-3, −7, −9; 1.17–1.61 fold) and suppressed anti-apoptotic/invasion proteins (BCL-2, MMP2, MMP9; 1.46–2.01 fold), confirming intrinsic apoptosis activation. Flow cytometry revealed that HB147 reduced the G0/G1 population (96.43 → 79.09%) and induced arrest at S (2.95 → 16.8%) and G₂/M (0.63 → 22.08%) phases. Besides, to further investigate the apoptotic potential of analogues HB68 and HB147, a molecular docking study was conducted against the BCL-2 target receptor. In summary, HB147 displayed potent cytotoxic, pro-apoptotic, and cell cycle–arresting activities, underscoring its potential as a promising anticancer lead candidate.