Theranostic mesoporous platinum nanoplatform delivers halofuginone to remodel extracellular matrix of breast cancer without systematic toxicity

Abstract The enriched collagens in the extracellular matrix (ECM) of breast cancer substantially impede drug delivery. Halofuginone (HF), a potent antifibrotic agent, was effective to deplete the collagens and remodel the ECM by inhibiting the TGFβ pathway. However, the application of HF was hindered by its strong liver toxicity. Herein, mesoporous platinum (mPt) nanoparticles were constructed to load HF as theranostic nanoplatforms. mPt had a uniform spherical structure with a diameter of 79.83 ± 6.97 nm and an average pore diameter of 20 nm and exhibited good photothermal conversion efficiency of 62.4%. The obtained HF‐loaded nanoplatform (PEG@mPt‐HF) showed enhanced cytotoxicity through the combination of photothermal therapy and the anti‐TGFβ effect induced by HF. The animal imaging and histochemical assays confirmed the PEG@mPt‐HF could efficiently deliver HF to tumors (monitored by CT) and remodel the ECM by TGFβ pathway inhibition, which resulted in increased anti‐cancer efficacy. Importantly, the liver toxicity observed in HF‐treated mice was negligible in those treated by PEG@mPt‐HF. Overall, this study designed a theranostic nanoplatform to remodel the ECM with remarkably reduced systematic toxicity and enhance the therapeutic efficacy through combination treatment.