An Activatable Nanoscintillator Probe for Detecting Telomerase Activity and Screening Inhibitors In Vivo

Telomerase represents an essential molecular machinery for tumor occurrence and progression and a potential therapeutic target for cancer treatment. Sensitive and reliable analysis of telomerase activity is of significant importance for the diagnosis and treatment of cancer. In this study, we developed a telomerase-activated nanoscintillator probe for deep-tissue and background-free imaging of telomerase activity and screening telomerase inhibitors in tumor-bearing living mice models. The probe was constructed by modifying lanthanide-doped nanoscintillators with aptamer-containing DNA anchor strands which hybridized with quencher labelled–oligonucleotide strands and telomerase primers. The X-ray-induced fluorescence of the probe was quenched originally but turned on upon telomerase-catalyzed extension of the primer. Benefiting from exceptional tissue penetrating properties and negligible autofluorescence of X-ray excitation, this probe enabled direct detection of telomerase activity in vivo via fluorescence imaging. Furthermore, with the direct, readable fluorescent signals, the probe enabled the screening of telomerase inhibitors in living cells and whole-animal models in the native states of telomerase. This strategy would inspire the development of low autofluorescence and deep tissue bioimaging probes for disease diagnosis and drug development in high-level living settings.