Synergistic Mn-MOF Activation of Pistol Ribozymes for Cancer Immunotherapy

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 Mn2 + cofactors. NKMOF-101-[Mn] not only protects the ribozyme from nuclease degradation but also enables localized Mn2 + 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.