Strategic Engineering of Imidazopyridine-Benzoxazole Hybrids Targeting Microtubule Dynamics: Comprehensive Inhibition of the Metastatic Cascade

Abstract

A series of twenty novel imidazopyridine-benzoxazole hybrid (Imp1-20) derivatives was designed and synthesized, and their antiproliferative activities were evaluated against MDA-MB-231 breast and DLD-1 colorectal cancer cell lines. Among them, Imp-18 and Imp-20 emerged as the most potent candidates, with low micromolar to nanomolar IC50 values and significant reductions in cancer cell adhesion and colony formation. Flow cytometry analyses demonstrated that both compounds induced apoptosis and promoted cell-cycle arrest, reflected by Sub-G1 accumulation and perturbations in G1/G0 and G2/M phases. Immunofluorescence imaging of beta-tubulin confirmed that Imp-18 and Imp-20 compromise microtubule integrity, with Imp-18 displaying stronger tubulin-disrupting activity than nocodazole. The resulting microtubule destabilization was consistent with mitotic arrest and activation of apoptotic signaling pathways. Additionally, both compounds markedly inhibited cancer cell migration, indicating an ability to impair metastatic behavior. Overall, these findings identify Imp-18 and Imp-20 as promising microtubule-targeting agents with robust anticancer potential, providing a strong basis for further mechanistic studies and structural optimization within the framework of medicinal and bioorganic chemistry.