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

## TL;DR

A new pre-targeting system using a synthetic zipper improves cancer cell targeting and destruction in near-infrared photoimmunotherapy.

## Contribution

A synthetic zipper-mediated pre-targeting system is introduced for enhanced and specific near-infrared photoimmunotherapy.

## Key findings

- The system achieves selective phototoxicity with an IC50 range of ∼104–1,179 nM.
- The treatment induces cell death in ∼86%–94% of cells and triggers immunogenic cell death (ICD).
- ICD is evidenced by increased surface exposure of calreticulin, HSP70, and HSP90.

## 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.

•Synthetic zipper enables pre-targeting of NIR-PIT in cancer cells•ScFv-Zip2 fusion proteins target FOLR1, TROP2, and TF antigens•Synthetic zipper mediated NIR-PIT systems induces potent cancer cell death•Triggers immunogenic cell death via calreticulin and HSP exposure

Synthetic zipper enables pre-targeting of NIR-PIT in cancer cells

ScFv-Zip2 fusion proteins target FOLR1, TROP2, and TF antigens

Synthetic zipper mediated NIR-PIT systems induces potent cancer cell death

Triggers immunogenic cell death via calreticulin and HSP exposure

Drug delivery system; Conjugate; Biological sciences; Cell biology; Cancer