Ultrasound-Activated Hydrogen-Bonded Organic Framework Synergistically Enhances Antitumor Immunity by Epigenetic Reprogramming and Pyroptosis Induction.

Pyroptosis, a pro-inflammatory form of cell death, elicits robust antitumor immune responses. However, pyroptosis-based cancer immunotherapy is hampered by the epigenetic silencing of gasdermin E (GSDME) through hypermethylation of the DFNA5 gene. To overcome this limitation, we engineered an innovative nanosystem by first synthesizing a reactive oxygen species (ROS)-responsive decitabine prodrug (DTO), which was subsequently encapsulated within hydrogen-bonded organic frameworks to form the HDTO nanoplatform. Upon ultrasound (US) activation, the HDTO nanoplatform exhibited potent ROS generation, enabling two complementary functions: (1) triggering decitabine release to demethylate DFNA5 and restore GSDME expression and (2) activating caspase-3, thereby initiating the caspase-3/GSDME-mediated pyroptotic pathway. This apoptosis-to-pyroptosis switching mechanism significantly enhanced immunogenic cell death and potentiated antitumor immunity. In vivo studies demonstrated that US-activated HDTO induced robust pyroptosis, remodeled the tumor microenvironment, and elicited superior antitumor immune responses, resulting in marked suppression of tumor growth and metastasis. Single-cell RNA sequencing analysis confirmed that HDTO + US-induced pyroptosis depleted nonimmune cells while expanding monocyte and neutrophil populations, demonstrating effective immunoreprogramming. This study establishes a novel therapeutic paradigm that synergistically integrates epigenetic modulation with pyroptosis induction to enhance the efficacy of cancer immunotherapy.