Bispecific DNA-Peptide Probes for Targeting Receptor Pairs on Live Cells.

Area of Science:

• Biochemistry
• Molecular Biology
• Nanotechnology

Background:

• Chemical modification and nucleic acid self-assembly enable specific arrangements of protein receptor ligands.
• While homomultivalent interactions are well-studied, heteromultivalent interactions remain less explored.
• Existing bispecific agents often have high molecular weights.

Purpose of the Study:

• To investigate DNA duplexes for programming bispecific targeting of specific cell types.
• To leverage peptide-based binders for cell surface protein targeting in diagnostics and therapeutics.
• To determine optimal spatial arrangements for selective cell recognition based on receptor combinations.

Main Methods:

• Utilized DNA duplexes to link peptide-based high-affinity binders.
• Performed systematic spatial screening to identify optimal distances between peptides.
• Tested bispecific binders on cell lines expressing specific receptor combinations (e.g., VGFR2/α_Vβ₃ on HUVECs, EGFR/MET on A549 cells).
• Loaded DNA with cytotoxic payloads (e.g., Auristatin) for targeted delivery.

Main Results:

• Identified optimal distances between cyclopeptides for selective recognition of specific cell types.
• Found that VGFR2/α_Vβ₃ recognition on HUVECs required distances exceeding 20 nucleotides.
• Observed a different distance-affinity landscape for EGFR/MET recognition on A549 cells.
• Demonstrated specific cell targeting, efficient internalization, and selective payload delivery.
• Developed bispecific DNA-peptide probes with significantly lower molecular weights than existing agents.

Conclusions:

• DNA-programmed bispecific binders offer a novel approach for targeted cell recognition and therapy.
• Optimizing the spatial arrangement of peptide binders is crucial for achieving high specificity.
• These DNA-peptide probes represent a promising, low-molecular-weight alternative for diagnostics and therapeutics.