title: PAMAM dendrimers as delivery agents for antisense oligonucleotides.
abstract: OBJECTIVE
  To investigate the potential use of PAMAM dendrimers for the delivery of antisense oligonucleotides into cells under conditions that mimic the in vivo environment.
  
  
  METHODS
  We used HeLa cells stably transfected with plasmid pLuc/705 which has a luciferase gene interrupted by a human beta-globin intron mutated at nucleotide 705, thus causing incorrect splicing. An antisense oligonucleotide overlapping the 705 splice site, when delivered effectively, corrects splicing and allows luciferase expression. The ability of dendrimers to deliver oligonucleotides to HeLa Luc/705 cells was evaluated in the absence or presence of serum.
  
  
  RESULTS
  PAMAM dendrimers formed stable complexes with oligonucleotides that had modest cytotoxicity and showed substantial delivery activity. The dose of the oligonucleotide, the charge ratio of oligonucleotide to dendrimer, and the size (generation) of the dendrimers were all critical variables for the antisense effect. The physical properties of dendrimer/oligonucleotide complexes were further investigated using sedimentation and gel electrophoresis methods. Effective oligonucleotide/generation 5 dendrimer complexes were macromolecular rather than particulate in nature, and were not sedimented at 100,000 RPM. Compared to other types of delivery agents, PAMAM dendrimers were more effective in delivering oligonucleotides into the nucleus of cells in the presence of serum proteins.
  
  
  CONCLUSIONS
  Our results suggest that PAMAM dendrimers form nonparticulate delivery complexes that function in the presence of serum proteins and thus may be suited for in vivo therapeutic applications.
authors.affiliation: Department of Pharmacology, University of North Carolina, Chapel Hill 27599, USA.
authors.forename: H
authors.initials: H
authors.lastname: Yoo
authors.forename: P
authors.initials: P
authors.lastname: Sazani
authors.forename: R L
authors.initials: RL
authors.lastname: Juliano
mesh_terms: D001798:Blood Proteins / Q000737:chemistry; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D050091:Dendrimers; D004337:Drug Carriers; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008970:Molecular Weight; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage* / Q000494:pharmacology; D011073:Polyamines; D014461:Ultracentrifugation
chemical_list: D001798:Blood Proteins; D050091:Dendrimers; D004337:Drug Carriers; D016376:Oligonucleotides, Antisense; C104700:PAMAM Starburst; D011073:Polyamines