Hypoxia-Directed and Self-Immolative Theranostic Agent: Imaging and Treatment of Cancer and Bacterial Infections.

The impact of bacteria on cancer progression and treatment is becoming increasingly recognized. Cancer-associated bacteria are linked to metastases, reduced efficacy, and survival challenges. In this study, we present a sensitive hypoxia-activated prodrug, NR-NO 2 , which comprises an antibiotic combined with a chemotherapeutic. This prodrug demonstrates rapid and robust fluorescence enhancement and exhibits potent antibacterial activity against both Gram-positive and Gram-negative bacteria as well as tumor cells. Upon activation, NR-NO 2 produces a distinct "fluorescence-on" signal, enabling real-time drug release monitoring. By leveraging elevated nitroreductase in cancer cells, NR-NO 2 gives rise to heightened bacterial cytotoxicity while sparing normal cells. In A549 solid tumor-bearing mice, NR-NO 2 selectively accumulated at tumor sites, displaying fluorescence signals under hypoxia superior to those of a corresponding prodrug-like control. These findings highlight the potential of NR-NO 2 as a promising cancer therapy prodrug that benefits from targeted release, antibacterial impact, and imaging-based guidance.