Simultaneous Visualization and Depletion of Peroxynitrite by a Simple Aggregation-Induced Emission Nanoprobe for Preventing Breast Cancer Metastasis after Surgery

Inflammation has been confirmed to be closely related to the development of tumors, while peroxynitrite (ONOO^-) is one of the most powerful oxidative pro-inflammatory factors. Although ONOO^- can kill bacteria through oxidation, it will activate matrix metalloproteinases (MMPs), accelerate the degradation of the extracellular matrix (ECM), and subsequently lead to the activation and release of other tumor promotion factors existing in the ECM, promoting tumor metastasis and invasion. Herein, we report a simple aggregation-induced emission (AIE) nanoprobe (NP), TPE-4NMB, that can simultaneously visualize and deplete ONOO^-. The probe can light up the endogenous and exogenous ONOO^- in cells and selectively inhibit the proliferation and migration of 4T1 cells by inducing an intracellular redox homeostasis imbalance through ONOO^- depletion. After being modified with DSPE-PEG₂₀₀₀, the TPE-4NMB NPs can be used to image ONOO^- induced by various models in vivo; especially, it can monitor the dynamic changes of ONOO^- level in the residual tumor after surgery, which can provide evidence for clarifying the association between surgery, ONOO^-, and cancer metastasis. Excitingly, inhibited tumor volume growth and decreased counts of lung metastases were observed in the TPE-4NMB NPs group, which can be attributed to the downregulated expression of MMP-9 and transforming growth factor-β (TGF-β), increased cell apoptosis, and inhibited epithelial-mesenchymal transition (EMT) mediated by ONOO^-. The results will provide new evidence for clarifying the relationship between surgery, ONOO^-, and tumor metastasis and serve as a new intervention strategy for preventing tumor metastasis after tumor resection.