Glycosaminoglycan dependent cell‐penetrating peptide derived from human eosinophil cationic protein

Abstract

Alterations in Glycosaminoglycan (GAG) expression, especially HS, can be a contributing factor in the progression of growth, extracellular matrix ‐remodeling and migration. We have elucidated eosinophil cationic protein (ECP) binds Beas‐2B cell surface HS and enters the cells. Based on this study, a sequence, RWRCK, was identified as a core GAG‐binding motif; sequence analysis led to a novel cell‐penetrating peptide (CPPecp) derived from this GAG‐binding motif. FITC, eGFP and peptidomimetic drug have been delivered into cells by CPPecp. To clarify the roles of GAGs for CPPecp function, binding of CPPecp to GAG derivatives were evaluated by fluorophore‐assisted carbohydrate electrophoresis. Interestingly, although showing high affinity towards both HS and CS in cell‐free assays, binding and entry of CPPecp to Beas‐2B identified by enzyme‐linked immunosorbent assay, flow cytometry and confocal laser scanning microscopy revealed that CPPecp specifically anchored to cell surface HS prior to penetration into cells. In addition, binding and entry of CPPecp to wild‐type and GAG‐deficient mutant strains of Chinese hamster ovary cells supported that HS was specific target molecule for CPPecp recognition. Furthermore, lipid‐rafted endocytosis was the major route for CPPecp internalization. Taken together, CPPecp may be developed as extracellular HS‐targeted drug delivery purposes.