A Fluorescent Chemosensor for Long‐Term Tracking of Cancer Cell Metastasis and Invasion via Enzyme‐Activated Anchoring

Evidence shows that the enzyme human cytochrome P450 1A1 (CYP1A1) is associated with cancer; indeed, it is shown to play a key role in the occurrence of many cancers. Therefore, the molecular imaging of CYP1A1 in cells is of great significance for revealing the process of cancer development. Herein, a chemosensor, DCBEM, is reported that is able to selectively recognize CYP1A1 and achieve long‐term labeling of the enzyme through an enzymolysis cascade reaction. The design of DCBEM relies on the reaction between the highly electrophilic intermediate (quinone methide) and the enzyme, which forms a fluorescent label with CYP1A1 via covalent bonding. The chemosensor reveals excellent specificity toward CYP1A1 and achieves high‐resolution monitoring of cell migration with a strong retention capacity in vivo (up to 4 days). Further, using DCBEM, the pathways of invasion of colon cancer and breast cancer cells are successfully visualized in living mice. This method of labeling enzymes provides a simple and efficient way to render ordinary fluorescent chemosensors suitable for the long‐term tracking of cancer cells, for which such molecular tools are currently lacking. Combining fluorescence recognition with an enzyme labeling strategy through an enzymolysis cascade reaction, the chemosensor DCBEM forms a fluorescent label with CYP1A1 via covalent bonding, providing long‐term molecular imaging of CYP1A1 in cancer cells up to 4 days, based on which the migration pathways of CYP1A1‐related cancers are clearly revealed through fluorescence in vivo.