Anticancer Effect of Co(III) Complex of a Thiourea Derivative on Inhibiting Breast Cancer Cell Proliferation Using In Silico and In Vitro Evaluations

Breast cancer remains a leading cause of cancer‐related mortality worldwide, highlighting the need for novel therapeutic agents with improved selectivity and multifunctional activity. In this study, a novel cobalt(III) complex, Co(L2) ₃ [L2 = 2‐chloro‐N‐(2,2‐dimethyloxazolidine‐3‐carbonothioyl)benzamide], was synthesized and evaluated using integrated in vitro and in silico approaches. The ligand and complex were characterized by FT‐IR, UV–Vis, and ¹ H NMR spectroscopy. The antiproliferative activity was assessed in MCF‐7, MDA‐MB‐231, and HUVEC cells using the MTT assay. IC ₅₀ values were 176.95 ± 2.84 µg/mL for MCF‐7, 187.01 ± 0.47 µg/mL for MDA‐MB‐231, and 354.96 ± 1.14 µg/mL for HUVEC cells, corresponding to selectivity indices of 2.01 and 1.90, respectively. Co(L2) ₃ reduced colony formation and cell migration and increased glutathione reductase activity. Gene expression analysis showed upregulation of CASP3 and CASP9 and downregulation of BCL2, CDC25A, MMP2, and MMP9, indicating modulation of apoptosis‐, cell‐cycle‐, and metastasis‐related responses. Molecular docking predicted favorable interactions with CDC25A, MMP‐2, and MMP‐9. Collectively, these findings indicate that Co(L2) ₃ exhibits preferential in vitro anticancer activity against the tested breast cancer cell lines and warrant further investigation as a potential multifunctional anticancer agent.