Spatiotemporal targeting of miR-125b-5p regulatory hub via dual-ligand nanocarriers to polarize tumor-associated macrophages towards tumoricidal phenotype in breast cancer microenvironment

초록

Reprogramming tumor-associated macrophages (TAMs) from an immunosuppressive M2 state toward a tumoricidal M1 phenotype is a promising strategy for cancer immunotherapy. Using multiMiR network analysis, miR-125b-5p is identified as a central regulatory hub controlling macrophage polarization. In vitro validation confirmed that miR-125b-5p inhibition induces M1 polarization, marked by upregulated CD86, pSTAT1, IRF1, COX-2, p65, iNOS, TNF alpha and IL-6 in M0 and M2 macrophages. Metabolic profiling revealed that miR-125b-5p inhibition in pre-primed activated M2 macrophages significantly suppressed basal respiration, driving robust repolarization. To address translational hurdles, cationic mesoporous silica nanoparticles (AMSN) functionalized with dialdehyde hyaluronic acid (dHA) and mannose (dHA-Mannose/AMSN) were engineered. A pH-labile calcium phosphate (CaP) gatekeeper was introduced to maximize miRNA retention in dHA-Mannose/AMSN and trigger release specifically within acidic endo-lysosomes. This dHA-Mannose/AMSN platform demonstrated superior internalization in M2 macrophages via dual targeting of CD44 and CD206, effectively differentiating TAMs from circulating monocytes. In orthotopic 4T1 breast tumor mice models, the system achieved significant intratumoral accumulation. Immunohistochemical staining (IHC) confirmed that miR-125b-5p mimic drastically increased immunosuppressive Arginase-1+ M2 populations, whereas miR-125b-5p inhibition increased tumoricidal iNOS+ M1 population and promoted tumor apoptosis. In addition, IHC also showed increased in dendritic markers MHC II and ITGAX. Collectively, this work establishes CaP-gated dHA-Mannose/ AMSNs as a precision nanocarrier for spatiotemporal immune rewiring and validates miR-125b-5p as a therapeutic regulator of TAM polarization.

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