Unprecedented Sensitivity in a Probe for Monitoring Cathepsin B: Chemiluminescence Microscopy Cell‐Imaging of a Natively Expressed Enzyme

• Published in: Angewandte Chemie International Edition Vol. 56; no. 49; pp. 15633 - 15638
• Main Authors: Roth‐Konforti, Michal E., Bauer, Christoph R., Shabat, Doron
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 04.12.2017
• Edition: International ed. in English
• Subjects: 3T3 Cells; Animals; Cathepsin B - analysis; Cathepsin B - metabolism; cathepsin B; Cells, Cultured; Chemiluminescence; Colon; dioxetanes; Enzymes; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Fluorescent Dyes - metabolism; Fluorescent indicators; Humans; Imaging; Leukemia; live-cell imaging; Luciferases - metabolism; Luminescent Measurements; Mice; Microscopy; molecular probes; Molecular Structure; Optical Imaging; Probes; RAW 264.7 Cells; dioxetanes; molecular probes; chemiluminescence; cathepsin B; live-cell imaging
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201709347

Until recently, chemiluminescence cell images could only be obtained using luciferase‐activated probes. Moreover, chemiluminescence microscopy cell‐imaging has not been demonstrated for natively expressed enzymes like cathepsin B. Herein, we describe the design, synthesis, and evaluation of the first chemiluminescence probe for the detection and imaging of cathepsin B. The probe activation mechanism relies on the release of a dioxetane intermediate, which undergoes chemiexcitation to emit green light with high efficiency under physiological conditions. Using the probe, we obtained clear images of cancerous leukemia and colon cells. This is the first demonstration of chemiluminescence cell images obtained by a probe for a natively expressed endogenous enzyme. We anticipate that the concept presented in this study will be broadly used to develop analogous probes for other important proteases relevant to biomolecular processes. Chemiluminescence cell‐imaging: The first chemiluminescence probe for the detection of cathepsin B is described. The probe showed unprecedented sensitivity compared to that of a classic fluorescent probe for cathepsin B and provided the first chemiluminescence microscopy cell images of a natively expressed enzyme, thereby enabling differentiation between cancerous cells and normal tissue.