title: Enhanced gene transfection with addition of a cell-penetrating peptide in substrate-mediated gene delivery.
abstract: BACKGROUND
  To overcome extracellular barriers in gene therapy, controlled release technology has been adapted to protect DNA from degradation and maintain elevated DNA concentration. Although cell-penetrating peptides (CPPs) have been widely utilized to enhance the transfection efficiency of solution-based transfections, as far as we are aware, the effect of these peptides on substrate-mediated transfection has not yet been reported.
  
  
  METHODS
  In the present study, the effect of a CPP, KALA, on the substrate-mediated gene delivery was studied. A fast degrading cholic acid functionalized star poly((DL)-lactide) was used to fabricate Ca-P/DNA/KALA co-precipitates-deposited films and Ca-P/DNA/KALA co-precipitates-encapsulated films for mediating substrate-mediated transfection. The in vitro gene transfections in HEK293T and HepG2 cells mediated by the different films were investigated. The effect of KALA content on gene transfection was studied.
  
  
  RESULTS
  Gene expression of film-mediated transfections could be significantly enhanced by the addition of KALA at a quite low content with a DNA/KALA ratio of 10 : 1. As a result of the surface erosion mechanism of the functionalized star poly((DL)-lactide), our substrate-mediated transfection system could rapidly release Ca-P/DNA/KALA to mediate efficient gene expression. During the transfection, the degradation of the polymer films could be observed and the degradation did not show any unfavorable effects on gene expression.
  
  
  CONCLUSIONS
  The presence of a CPP could significantly enhance the gene expression of substrate-mediated transfections.
authors.affiliation: Key Laboratory of Biomedical Polymers of Ministry of Education, Department of Chemistry, Wuhan University, Wuhan, People's Republic of China.
authors.forename: Si
authors.initials: S
authors.lastname: Chen
authors.forename: Ren-Xi
authors.initials: RX
authors.lastname: Zhuo
authors.forename: Si-Xue
authors.initials: SX
authors.lastname: Cheng
mesh_terms: D002460:Cell Line; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D015316:Genetic Therapy; D056945:Hep G2 Cells; D006801:Humans; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity; D014162:Transfection / Q000379:methods*
chemical_list: D004268:DNA-Binding Proteins; C105114:KALA amphipathic peptide; D010455:Peptides; D011091:Polyesters; C033616:poly(lactide); D004247:DNA