Affibody-displaying bio-nanocapsules effective in EGFR, typical biomarker, expressed in various cancer cells

The expression of epidermal growth factor receptor (EGFR) across a wide range of tumor cells has attracted attention for use as a tumor marker in drug delivery systems. Therefore, binding molecules with the ability to target EGFR have been developed. Among them, we focused on affibodies that are binding proteins derived from staphylococcal protein A. By displaying affibody (Z_EGFR) binding to EGFR on the surface of a bio-nanocapsule (BNC) derived from a hepatitis B virus (HBV), we developed an altered BNC (Z_EGFR-BNC) with a high specificity to EGFR-expressing cells. We considered two different types of Z_EGFR (Z955 and Z1907), and found that the Z1907 dimer-displaying BNC ([Z1907]₂-BNC) could effectively bind to EGFR-expressing cells and deliver drugs to the cytosol. Since this study showed that [Z1907]₂-BNC could target EGFR-expressing cells, we would use this particle as a drug delivery carrier for various cancer cells expressing EGFR.