Bioactive fibrous microwell platforms induce m1 macrophage clusters that enhance anti-tumor activity and T cell polarization☆

Abstract

Engineering immune-regulatory microenvironments that direct macrophage function is central to advancing immunotherapies for solid tumors. Here, we present a bioactive fibrous microwell platform that integrates electrospun polycaprolactone/polyvinylpyrrolidone (PCL/PVP) nanofibers with photopatterned threedimensional confinement and sustained lipopolysaccharide (LPS) delivery, enabling the formation of stable M1-polarized macrophage clusters beyond conventional transient stimulation. The hybrid microenvironment guided macrophages into compact clusters while providing continuous pro-inflammatory cues. As a result, macrophages exhibited pronounced M1-like characteristics, including elevated inflammatory cytokine production, cytoskeletal and metabolic remodeling, and enhanced tumoricidal activity against breast and melanoma tumor models. Proteomic analyses revealed coordinated regulation of cytoskeletal, stress-response, metabolic, and translational pathways underlying this phenotype. Importantly, the macrophage-derived pro-inflammatory secretomes promoted cytokine-driven polarization of na & iuml;ve CD4+ and CD8+ T cells toward Th1-, Th17-, and effector-like phenotypes, forming a functional innate-adaptive immune cascade that contributed to robust tumor cell apoptosis. Together, these results establish the fibrous microwell platform as a versatile immunomodulatory system that couples macrophage programming with T cell polarization for enhanced anti-tumor immunity.