In situ enzymatic peptide-based nanomedicine with combined effects for enhanced tumor radio-immunotherapy

Despite the combination of radiotherapy and immunotherapy in clinical practice have shown promising synergistic anti-tumor effect, the immunosuppressive tumor microenvironment (TME) remains to be one of stumbling block impeding the therapeutic efficacy of radio-immunotherapy. In this study, in situ self-assembled peptidebased drug delivery systems with multiple effects were constructed for enhancing tumor radio-immunotherapy. The two peptide-drug conjugates could co-assembled into peptide-based nanomedicine on the cancer cell membrane under enzyme catalysis and continuously release small molecular active drugs in the cytoplasm, which combined action lead YAP phosphorylation and nuclear transfer failure. By simutaneously suppressing glycolysis and reactivating the dysfunctional Hippo pathway, the peptide-based nanomedicine also remitted the immunosuppressive TME by reducing lactate levels and the expression of immunosuppressive factors, respectively. As a result, the pro-tumorigenic M2 phenotype of tumor-associated macrophages (TAMs) was decreased and the anti-tumorigenic M1 phenotype of TAMs was increased. Such a dual intervention strategy from cellular metabolic level and gene transcription level not only inhibited tumor cell proliferation but also reversed the immunosuppressive TME, thereby augmenting the combined efficacy of radiotherapy and immune checkpoint blockade (ICB) therapy. The work is anticipated to contribute novel insights into anti-cancer drug targeted delivery and tumor multi-modal synergistic therapy.