Preclinical identification of an oxadiazole-pyrazole lead targeting prostate cancer through integrated mechanistic evaluation

Abstract

Prostate cancer remains a major cause of cancer-related mortality among men, while resistance to androgen deprivation therapy emphasizes the need for new therapeutic strategies. Molecular hybridization of pharmacologically relevant heterocycles offers a rational approach for developing novel anticancer agents. Twenty oxadiazole–pyrazole hybrids (VS-01–VS-20) were designed, synthesized, and evaluated using molecular docking against the androgen receptor (PDB ID: 1Z95), followed by in vitro antiproliferative assessment against androgen-dependent LNCaP and androgen-independent PC-3 prostate cancer cells. The lead compound was further investigated for its effects on androgen receptor expression, intracellular reactive oxygen species (ROS), cell-cycle progression, and apoptosis using flow cytometry and fluorescence microscopy. ADMET properties were additionally predicted computationally. VS-04 demonstrated a favorable interaction profile within the androgen receptor ligand-binding pocket and exhibited potent antiproliferative activity, with IC 50 values of 394.95 ± 3.03 nM against PC-3 and 464.85 ± 4.29 nM against LNCaP cells. Docking–activity correlation analysis revealed a moderate and significant association between docking affinity and PC-3 antiproliferative activity, whereas no significant correlation was observed for LNCaP cells. VS-04 treatment produced a concentration-dependent reduction in androgen receptor expression and increased intracellular ROS levels. Mechanistic studies further demonstrated pronounced S-phase accumulation and induction of apoptosis, with the total apoptotic population increasing from 7.45% in control cells to 47.83% following VS-04 treatment. The integrated computational and experimental evaluation identified VS-04 as a promising oxadiazole–pyrazole lead with potent antiproliferative activity against prostate cancer cells. Its activity was associated with AR modulation, oxidative stress, cell-cycle perturbation, and apoptotic cell death, supporting further structural optimization and preclinical investigation of this scaffold for prostate cancer therapy.