Direct Real-Time Monitoring of Prodrug Activation by Chemiluminescence.

The majority of theranostic prodrugs reported so far relay information through a fluorogenic response generated upon release of the active chemotherapeutic agent. A chemiluminescence detection mode offers significant advantages over fluorescence, mainly due to the superior signal-to-noise ratio of chemiluminescence. Here we report the design and synthesis of the first theranostic prodrug monitored by a chemiluminescence diagnostic mode. As a representative model, we prepared a prodrug from the chemotherapeutic monomethyl auristatin E, which was modified for activation by ß-galactosidase. The activation of the prodrug in the presence of ß-galactosidase is accompanied by emission of a green photon. Light emission intensities, which increase with increasing concentration of the prodrug, were linearly correlated with a decrease in the viability of a human cell line that stably expresses ß-galactosidase. We obtained sharp intravital chemiluminescent images of endogenous enzymatic activity in ß-galactosidase-overexpressing tumor-bearing mice. The exceptional sensitivity achieved with the chemiluminescence diagnostic mode should allow the exploitation of theranostic prodrugs for personalized cancer treatment.