New indole-linked 1,2,4-triazole derivatives as dual FAK inhibitors and apoptosis inducers targeting survival and migration in triple-negative breast cancer in-vitro

Abstract Focal adhesion kinase (FAK) is overexpressed and hyperactivated in triple-negative breast cancer, driving tumor aggressiveness and cancer stem cell–mediated therapy resistance. Therefore, targeting FAK signalling represents a promising therapeutic strategy. In this study, a series of indole and bis-indole-1,2,4-triazoles were synthesized and evaluated as anti-TNBC agents targeting FAK. Compounds 3c , 4c , and 5c displayed potent cytotoxicity (IC₅₀ = 41–77 µg/mL) with minimal toxicity to normal cells, outperforming precursor compound 2 . Wound-healing assay revealed significant inhibition of cell migration, particularly by 4c . Cell cycle analysis revealed that 4c induced S-phase arrest in MCF-7 cells and G1-phase arrest in MDA-MB-231 cells, accompanied by significant apoptosis. In MDA-MB-231 cells, 4c triggered extensive total apoptosis (90.84%) with minimal necrosis. Gene expression studies demonstrated that 4c markedly downregulated PTK2 (FAK), CCL5 , and BCL2 , while upregulating CASP3 , highlighting its dual role as FAK inhibitor and apoptosis inducer. Importantly, 4c efficiently suppressed FAK protein expression (61.3%) in TNBC, compared to the FAK inhibitor GSK-2256098 (70.7%). In vivo toxicity assessment confirmed good tolerability in mice without profound hepatic or renal impairments, while docking and ADMET analyses confirmed strong FAK binding affinity, and favourable pharmacokinetics of 4c . Collectively, 4c emerges as a promising FAK-targeted candidate for TNBC therapy.