A Nitroreductase-Activated Chemiluminescent Prodrug for Real-Time Monitoring of Camptothecin Release in Peritoneal Metastasis Theranostics

While most theranostic prodrugs utilize fluorescence for reporting, chemiluminescence offers superior signal-to-noise ratios. However, chemiluminescence-based prodrug systems remain relatively scarce. Herein, we report the development of CPT-NBz-CL, a novel hypoxia-responsive theranostic prodrug activated by nitroreductase (NTR) via a self-immolative linker mechanism. This activation concomitantly releases a potent chemotherapeutic camptothecin (CPT) and generates a robust chemiluminescence signal for reporting. Encapsulation of CPT-NBz-CL into nanoparticles (CPT-NBz-CL NPs) facilitated in vivo application. In vitro studies demonstrated hypoxia-selective cytotoxicity and chemiluminescence generation. In a murine 4T1-Luc1 peritoneal metastasis model, CPT-NBz-CL NPs delineated hypoxic tumor regions through in vivo chemiluminescence imaging, reflecting the endogenous NTR activity. Crucially, CPT-NBz-CL NPs showed antitumor efficacy comparable to free CPT while significantly mitigating the parent drug's systemic toxicity. This work validates an NTR-triggered, self-immolative chemiluminescence platform as a promising strategy for integrating high-sensitivity imaging with potent, targeted cancer therapy, offering an improved safety profile.