title: Degradable polyethylenimine derivate coupled to a bifunctional peptide R13 as a new gene-delivery vector.
abstract: BACKGROUND
  To solve the efficiency versus cytotoxicity and tumor-targeting problems of polyethylenimine (PEI) used as a nonviral gene delivery vector, a degradable PEI derivate coupled to a bifunctional peptide R13 was developed.
  
  
  METHODS
  First, we synthesized a degradable PEI derivate by crosslinking low-molecular-weight PEI with pluronic P123, then used tumor-targeting peptide arginine-glycine-aspartate-cysteine (RGDC), in conjunction with the cell-penetrating peptide Tat (49-57), to yield a bifunctional peptide RGDC-Tat (49-57) named R13, which can improve cell selection and increase cellular uptake, and, lastly, adopted R13 to modify the PEI derivates so as to prepare a new polymeric gene vector (P123-PEI-R13). The new gene vector was characterized in terms of its chemical structure and biophysical parameters. We also investigated the specificity, cytotoxicity, and gene transfection efficiency of this vector in αvβ3-positive human cervical carcinoma Hela cells and murine melanoma B16 cells in vitro.
  
  
  RESULTS
  The vector showed controlled degradation, strong targeting specificity to αvβ3 receptor, and noncytotoxicity in Hela cells and B16 cells at higher doses, in contrast to PEI 25 KDa. The particle size of P123-PEI-R13/DNA complexes was around 100-250 nm, with proper zeta potential. The nanoparticles can protect plasmid DNA from being digested by DNase I at a concentration of 6 U DNase I/μg DNA. The nanoparticles were resistant to dissociation induced by 50% fetal bovine serum and 600 μg/mL sodium heparin. P123-PEI-R13 also revealed higher transfection efficiency in two cell lines as compared with PEI 25 KDa.
  
  
  CONCLUSIONS
  P123-PEI-R13 is a potential candidate as a safe and efficient gene-delivery carrier for gene therapy.
authors.affiliation: Department of Pharmaceutics, Shanghai Hospital, Second Military Medical University, Shanghai, People's Republic of China.
authors.forename: Kehai
authors.initials: K
authors.lastname: Liu
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhu
authors.forename: Jingya
authors.initials: J
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Gao
authors.forename: Shen
authors.initials: S
authors.lastname: Gao
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003432:Cross-Linking Reagents / Q000737:chemistry* / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D003850:Deoxyribonuclease I / Q000737:chemistry; D004355:Drug Stability; D016650:Fluorescein-5-isothiocyanate; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D051379:Mice; D053758:Nanoparticles; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology; D010316:Particle Size; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology; D010957:Plasmids / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry* / Q000494:pharmacology; D014162:Transfection / Q000379:methods*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000494:pharmacology
chemical_list: D003432:Cross-Linking Reagents; D039302:Integrin alphaVbeta3; D009842:Oligopeptides; D010446:Peptide Fragments; D010455:Peptides; C568214:arginyl-glycyl-aspartyl-cysteine; D054322:tat Gene Products, Human Immunodeficiency Virus; D049452:Green Fluorescent Proteins; D011094:Polyethyleneimine; D004247:DNA; D003850:Deoxyribonuclease I; D016650:Fluorescein-5-isothiocyanate