title: Folic acid-tethered Pep-1 peptide-conjugated liposomal nanocarrier for enhanced intracellular drug delivery to cancer cells: conformational characterization and in vitro cellular uptake evaluation.
abstract: BACKGROUND
  A novel dual ligand-modified liposome, folic acid-tethered Pep-1 peptide-conjugated liposomal nanocarrier (FP-Lipo), was designed to overcome the nonselectivity of conventional penetrating peptide-tagged nanoparticulates and to provide the advantage of selective targeting of the folic acid receptor, which is frequently overexpressed on epithelial cancer cells.
  
  
  METHODS
  FP-Lipo was prepared by a sequential process of formation of a maleimide-derivatized small unilamellar vesicle, postinsertion of distearoyl phosphatidyl ethanolamine-polyethylene glycol 2000-folate to the vesicle, and Pep-1 peptide conjugation via thiol-maleimide linkage. Conformational and physical characteristics of the FP-Lipo nanocarriers were investigated for the extent of Pep-1 peptide and folic acid on the surface, vesicle size, and zeta potential. In vitro cellular uptake behaviors of the novel carrier containing a fluorescein dextran isothiocyanate probe were examined by spectrophotometry or by confocal laser scanning microscopy.
  
  
  RESULTS
  A novel nanocarrier bearing approximately 750 folate ligands and 100 penetrating peptides per vesicle was successfully prepared. The physical properties were as follows: 140 nm in size; 5 mV in zeta potential; less than 0.3 in polydispersity index. An in vitro cellular uptake study revealed that the FP-Lipo nanocarrier system exhibited more than twofold enhanced translocation into the folic acid receptor-positive HeLa cells compared with the single Pep-1 peptide-modified liposome. Meanwhile, its cellular association and internalization into the folic acid receptor-negative normal HaCaT cells was comparable with that of Pep-1 peptide-modified liposome.
  
  
  CONCLUSIONS
  An advanced dual ligand-modified liposome is potentially useful for the treatment of folic acid receptor-positive tumors with high translocation capability of the penetrating peptide-modified liposome.
authors.affiliation: College of Pharmacy, Chung-Ang University, Seoul, Korea.
authors.forename: Myung Joo
authors.initials: MJ
authors.lastname: Kang
authors.forename: Sang Han
authors.initials: SH
authors.lastname: Park
authors.forename: Mean Hyung
authors.initials: MH
authors.lastname: Kang
authors.forename: Min Jung
authors.initials: MJ
authors.lastname: Park
authors.forename: Young Wook
authors.initials: YW
authors.lastname: Choi
mesh_terms: D000595:Amino Acid Sequence; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D003543:Cysteamine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D016503:Drug Delivery Systems / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate; D005492:Folic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D006367:HeLa Cells; D006801:Humans; D042541:Intracellular Space / Q000737:chemistry / Q000378:metabolism; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008081:Liposomes / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry*; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D011487:Protein Conformation
chemical_list: D008081:Liposomes; C503924:Pep-1 peptide; D010455:Peptides; D003543:Cysteamine; D005492:Folic Acid; D016650:Fluorescein-5-isothiocyanate
keywords: Pep-1 peptide; cell-penetrating peptide; folic acid; intracellular delivery; liposome; targeted delivery