Engineering a curcumol-loaded porphyrinic metal-organic framework for enhanced cancer photodynamic therapy

Photodynamic therapy (PDT), a non-invasive and safe treatment, is a clinical promising alternative strategy for certain cancers. Although PDT can trigger tumor specific immunity, the immunosuppressive tumor microenvironment severely limits the efficacy of photodynamic immunotherapy. Curcumol (CUR), extracted from essential oils of traditional Chinese medicine, has potential immune activation effect for cancer immunotherapy. Considering the fat solubility and volatility hinder the in vivo application of essential oils, a metal-organic framework system (Named as CuTPyP/F68) composed of porphyrin and Cu2+ was constructed for delivering CUR (Named as CUR@CuTPyP/F68). The in vitro assays proved that CUR@CuTPyP/F68 could directly kill tumor cells by the released CUR and singlet oxygen (1O2) generated under laser irradiation (marked as '+'). Moreover, CUR@CuTPyP/F68 had superior tumor targeting and retention capabilities, which effectively inhibited tumor growth in vivo with only a single dose. Finally, the mechanism of CUR-mediated enhanced PDT had been firstly proposed: (1) CUR@CuTPyP/F68(+)-treated group exhibited more CD4+ and CD8+ T cells infiltration in tumor tissue; (2) CUR@CuTPyP/F68(+)-treated group exhibited high level of IFN-γ, IL-12 and TNF-α in blood. Overall, we believe the PDT-immunotherapy strategy has great potential for the treatment of breast cancer, and this work will provide a reference for the clinical application of essential oils in cancer immunotherapy.