Synergistic Mn‐MOF Activation of Pistol Ribozymes for Cancer Immunotherapy

ABSTRACT Checkpoint blockade therapies targeting PD‐L1 have revolutionized cancer immunotherapy, yet their efficacy is constrained by systemic immune toxicity and inadequate immune infiltration in certain tumor types. Here, we introduce a synergistic gene‐silencing nanosystem based on a target‐selective Pistol ribozyme (PS473) encapsulated within a manganese‐based, pH‐responsive metal–organic framework (NKMOF‐101‐[Mn]). The engineered PS473 exhibited high cleavage efficiency toward GU‐rich PD‐L1 mRNA motifs and was further activated by Mn ^{2 +} cofactors. NKMOF‐101‐[Mn] not only protects the ribozyme from nuclease degradation but also enables localized Mn ^{2 +} release to increase catalytic activity and innate immune signaling under the acidic tumor microenvironment. In vitro, PS473@NKMOF‐101‐[Mn] markedly suppressed PD‐L1 expression and promoted macrophage activation. In the B16F10 melanoma model, this system achieved over 90% tumor inhibition, enhanced immune cell infiltration and activation, and exhibited minimal systemic toxicity. Transcriptomic profiling further revealed the upregulation of immune‐related pathways, supporting a synergistic mechanism of gene silencing and immune activation. Overall, this study established a ribozyme‐directed immunotherapeutic platform with strong potential for precision cancer therapy via checkpoint modulation and immune reprogramming.