Synthetic zipper mediated pre-targeting system for near-infrared photoimmunotherapy

Abstract

Several strategies have gained attraction in cancer diagnosis and therapy, particularly to overcome the limitations associated with direct targeting approaches in radioimmunotherapy and photoimmunotherapy. Here, we have introduced a synthetic zipper-mediated pre-targeting system for near-infrared photoimmunotherapy (NIR-PIT) utilizing the IR700-conjugated Zip1-SNAP protein in combination with three scFv-ZIP2 fusion proteins targeting FOLR1, TROP2, and TF. In this two-step targeting approach, scFv-Zip2 proteins first bind to cancer-specific antigens, followed by hybridization with Zip1-SNAP-IR700 at cell surface via high-affinity zipper interaction. Upon NIR light irradiation, targeted cancer cells underwent selective phototoxicity in a concentration-dependent manner with IC50 range (∼104–1,179 nM). Notably, the treatment induced cell death in ∼86%–94% of cells and triggered ICD, as evidenced by increased (∼4– to 200-fold more) surface exposure of calreticulin, HSP70 and HSP90. These findings demonstrate that the synthetic zipper-mediated pre-targeting platform offers a promising and versatile strategy for enhancing the specificity and immunogenic potential of NIR-PIT in cancer therapy.