Selective detection of carboxylesterase 2 activity in cancer cells using an activity-based chemiluminescent probe.

Carboxylesterase 2 (CES2) has crucial roles in both xenobiotic metabolism and formation of pathogenic states including cancer. Thus, it is highly critical to monitor intracellular CES2 activity in living cancer cells. Here, we report a CES2 activatable phenoxy 1,2-dioxetane based chemiluminescent agent (CL-CES2). The probe exhibited a selective turn-on response in the presence of CES2 enzyme and enabled detection of CES2 activity in three different cancer cells that possess varying enzyme concentrations with high signal to noise ratios. In contrast no signal was obtained with CES1, an isoform of CES2 enzyme. CL-CES2 marks the first ever example of a CES2-responsive chemiluminescent luminophore and holds a great potential in further understanding the roles of CES2 activity in tumorogenesis.