Metal coordination micelles for anti-cancer treatment by gene-editing and phototherapy

CRISPR-Cas9 is a central focus of the emerging field of gene editing and photodynamic therapy (PDT) is a clinical-stage ablation modality combining photosensitizers with light irradiation. But metal coordination bio-materials for the applications of both have rarely been investigated. Herein, Chlorin-e6 (Ce6) Manganese (Mn) coordination micelles loaded with Cas9, termed Ce6-Mn-Cas9, were developed for augmented combination anti-cancer treatment. Manganese played multiple roles to facilitate Cas9 and single guide RNA (sgRNA) ribonu-cleoprotein (RNP) delivery, Fenton-like effect, and enhanced endonuclease activity of RNP. Histidine (His) -tagged RNP could be coordinated to Ce6 encapsulated in Pluronic F127 (F127) micelles by simple admixture. Triggered by ATP and endolysosomal acidic pH, Ce6-Mn-Cas9 released Cas9 without altering protein structure or function. Dual guide RNAs were designed to target the antioxidant regulator MTH1 and the DNA repair protein APE1, resulting in increased oxygen and enhanced PDT effect. In a murine tumor model, Ce6-Mn-Cas9 inhibited tumor growth with the combination therapy of PDT and gene editing. Taken together, Ce6-Mn-Cas9 represents a new biomaterial with a high degree of versatility to enable photo-and gene-therapy approaches.

Automated summary

This study developed a new biomaterial called Ce6-Mn-Cas9, which loaded Cas9 onto chlorin-e6 (Ce6) manganese (Mn) coordination micelles for combined anti-cancer treatment. Manganese played multiple roles in facilitating delivery, Fenton-like effect, and enhancing endonuclease activity of Cas9. Ce6-Mn-Cas9 released Cas9 triggered by ATP and endolysosomal acidic pH without altering protein structure or function. In a murine tumor model, Ce6-Mn-Cas9 inhibited tumor growth with the combination therapy of photodynamic therapy and gene editing. Ce6-Mn-Cas9 represents a versatile biomaterial for photo and gene therapy approaches.