Design, Synthesis, and Biological Evaluation of New Nitrogen and Sulfur-Containing Heterocycles as Potent Anticancer Agents: Insights from Apoptosis, Molecular Docking, and MD Simulations

Breast carcinoma is a major cause of female mortality, often worsened by the side effects and resistance to conventional chemotherapy. This study presents a new series of 3-(3-chlorobenzoyl) acetonitrile derivatives 3–16, designed through molecular hybridization to enhance therapeutic potency while minimizing toxicity to healthy tissues. The structural integrities of the synthesized targets were confirmed via elemental analysis, ESI-MS, 1H and 13C NMR, and FT-IR. 5-Oxothiazolylidene propanenitrile 14 was identified as the lead candidate, showing a cytotoxicity of IC50 = 2.263 ± 0.09 μM against MCF-7 cells, which is 2.5 times more effective than the reference Doxorubicin. It also displayed a Selectivity Index of 12.86, suggesting a substantial safety margin. Mechanistic investigations revealed that compound 14 induces apoptosis, causes cell cycle arrest at G0/G1, and inhibits cancer cell migration. The computational docking studies against the EGFR protein (PDB ID: 1M17) established that the 2-(thiazol-2-ylidene) propanenitrile 13 demonstrated superior binding stability comparable to Doxorubicin. While 4-(p-nitrophenyl) azopyrazole 9c exhibited stability, 2-(benzothiazol-2-ylidene) propanenitrile 16 was found to be less stable under simulated conditions. Conversely, compound 6 exhibited diminished efficacy and selectivity, as a result of significant steric hindrance and an over-reliance on aromatic character without adequate hydrogen-bonding motifs. Thepyrazol-4-yl methanone12 demonstrated high activity and selectivity, indicating that the aminopyrazole core, with its inherent hydrogen-bonding capacity, acts as a positive factor in modulating selectivity toward the MCF-7 cell line. Molecular docking studies confirmed strong binding to the EGFR receptor and favorable drug-like properties based on ADME profiles. These findings position these novel 3-chlorobenzoyl acetonitrile hybrids as promising, highly selective leads for next-generation oncological therapy.