A self-targeting MOFs nanoplatform for treating metastatic triple-negative breast cancer through tumor microenvironment remodeling and chemotherapy potentiation.

Triple-negative breast cancer (TNBC) is the most aggressive and fatal subtype of breast cancer with disappointing treatment and high mortality. Tumor microenvironment (TME) plays an important role in the invasion and metastasis of TNBC through multiple complex processes. Most anti-metastatic therapies only focus on cancer cells themselves or interfering with single factors of the metastasis process, which is often related to poor outcomes. Thus, effective TNBC treatment relies on regulating multiple key metastasis-related aspects of the TME. Herein, a self-targeting Metal-Organic Frameworks (MOFs) nanoplatform (named as MTX-PEG@TPL@ZIF-8) was designed to improve treatment of TNBC through tumor microenvironment remodeling and chemotherapy potentiation. The self-targeting MOF nanoplatform is consist of ZIF-8 nanoparticles loaded triptolide (TPL) and followed by the coating with methotrexate-polyethylene glycol conjugates (MTX-PEG). Due to MTX's affinity for the overexpressed folate receptor on tumor cell surfaces, MTX-PEG@TPL@ZIF-8 enables effective accumulation and deep penetration in the tumor area by an MTX-mediated self-targeting strategy. This MOF nanoplatform could promptly release the medication after penetrating the tumor cell, due to pH-triggered degradation. Its anti-metastasis mechanism is to inhibit tumor invasion and metastasis by down-regulating the expression of Vimentin, MMP-2 and MMP-9 and increasing the expression of E-cadherin, upregulation of cleaved caspase-3 and cleaved caspase-9 protein expression promote the apoptosis of tumor cells, thereby reducing their migration. It also downregulated the expression of VEGF and CD31 protein to inhibit the generation of neovascularization. Overall, these findings suggest the self-targeting MOF nanoplatform offers new insights into the treatment of metastatic TNBC by TME remodeling and potentiating chemotherapy.