A novel sono-activatable nanoreactor induces precision intratumoral juglone generation and caspase 3/GSDME-mediated pyroptosis for treatment of bladder cancer.

BACKGROUND

Juglone, a natural naphthoquinone compound, exhibits potent anticancer activity but faces clinical limitations due to poor solubility, low bioavailability, and systemic toxicity. While tumor microenvironment-responsive drug activation strategies offer a promising solution, achieving precise spatial control over the conversion of non-toxic precursors into cytotoxic agents remains a significant challenge.

METHODS

We developed DHN@Pt/PtMBCPsNSs, a platinum (Pt)-methylene blue (MB)- based nanoscale sonosensitizer, to enable ultrasound-triggered on-demand juglone synthesis within tumors. The system was evaluated in bladder cancer models including cell lines, patient-derived organoids (PDOs) and patient-derived tumor xenograft (PDX) models, assessing tumor uptake, intracellular distribution, hypoxia modulation ("H2O2-O2-¹O2" cascade), oxidative stress markers (SOD, GSH, MDA, GSSG), and cell death pathways (apoptosis/pyroptosis). Transcriptome sequencing was performed to elucidate molecular mechanisms.

RESULTS

DHN@Pt/PtMBCPsNSs were internalized by UMUC-3 and T24 cells and primarily accumulated within the mitochondrial compartments. The platinum-based components catalytically exhausted GSH via redox cycling. DHN@Pt/PtMBCPsNSs triggered the production of O2 and ¹O2 after local US irradiation, alleviating hypoxia and selectively converting dihydroxynaphthalene (DHN) to juglone in tumors, which reducing the systemic toxicity of juglone. The nanosystem further disrupted cellular redox balance by triggering depletion of antioxidant defenses (SOD and GSH) and reducing the ratio of GSH/GSSG. In vitro cell experiments and PDOs experiments demonstrated that DHN@Pt/PtMBCPsNSs combined with US irradiation can significantly inhibit bladder cancer cell proliferation, induce apoptosis, and regulate pyroptosis via the ROS-mediated caspase 3/GSDME signaling pathway. In the PDX model, DHN@Pt/PtMBCPsNSs accumulated at the tumor site and significantly inhibited tumor growth under US irradiation.

CONCLUSIONS

As a novel sonosensitizer and pyroptosis inducer, DHN@Pt/PtMBCPsNSs achieve a precise synergistic effect of chemotherapy and sonodynamic therapy within cells, while minimizing adverse effects on normal cells and overcoming the limitations associated with natural chemotherapeutic agents. This approach may advance clinical translation of natural anticancer agents.