C–C Chemokine Ligand 2 (CCL2) Recruits Macrophage-Membrane-Camouflaged Hollow Bismuth Selenide Nanoparticles To Facilitate Photothermal Sensitivity and Inhibit Lung Metastasis of Breast Cancer

Poor tumor accumulation, rapid clearance from blood circulation, and high risk of invasive and metastasis are the major barriers that encumber the conventional nanodrug-based tumor therapy. In this work, macrophage membrane (M)-camouflaged quercetin (QE)-loaded hollow bismuth selenide nanoparticles (abbreviated as M@BS-QE NPs) are fabricated for combination therapy of breast cancer. The resulting M@BS-QE NPs are comprehensively characterized, possessing prolonged circulation life, as well as accelerated and enhanced tumoritropic accumulation, compared with those of bare BS NPs because of the immune evading capacity, C–C chemokine ligand 2 (CCL2)-mediated recruitment properties, and active targeting ability. The subsequent QE release under near-infrared (NIR) laser irradiation can selectively sensitize cancer cells to photothermal therapy (PTT) by depleting heat shock protein 70 (HSP70, one malignancy-specific-overexpressed thermoresistance-related chaperone) to realize such a cascaded synergistic effect. At the same time, M@BS-QE NPs down-regulated p-Akt and matrix metalloproteinase-9 (MMP-9, which degrades the extracellular matrix to promote invasion and metastasis of tumors) signal axis to suppress breast cancer lung metastasis. Thus, our results provide a biomimetic strategy, using the characteristics of breast cancer and biological properties of macrophages, that hold great promise to enhance the therapeutic efficacy and improve the accuracy of treatment with minimal side effects on both primary and lung metastasis of breast cancer.