title: Multiple triphenylphosphonium cations as a platform for the delivery of a pro-apoptotic peptide.
abstract: OBJECTIVE
  Triphenyl phosphonium cations (TPPs) are delocalized lipophilic cations that accumulate in the mitochondria of cells. We have explore the effect of increasing the number of TPPs on delivery of a cell-impermeable pro-apoptotic peptide to intact cells.
  
  
  METHODS
  The pro-apoptotic peptide D-(KLAKLAK)(2) (KLA) was extended with 0-3 L-Lysines modified at their ε-amine with TPP. Peptides were studied in HeLa cells to determine their cytotoxic activity and cellular uptake.
  
  
  RESULTS
  In HeLa cells, the increased cytotoxicity correlates with the number of TPPs; the peptide with 3 TPP molecules (3-KLA) exerts the highest cytotoxic activity. This FITC-labeled peptide is found to accumulate in intact HeLa cells, whereas peptides with 0-2 TPPs are not detected at the same peptide concentration. Mitochondria-dependent apoptosis of HeLa cells in the presence of 3-KLA was followed by propidium iodide, Annexin-V and DiOC fluorescence by FACS.
  
  
  CONCLUSIONS
  A facile synthetic methodology has been presented for the delivery of a biologically active peptide into mitochondria of intact cells by attaching multiple TPP moieties to the peptide. This approach was shown to dramatically increase biological activity of the peptide as a pro-apoptotic agent.
authors.affiliation: Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
authors.forename: Netanel
authors.initials: N
authors.lastname: Kolevzon
authors.forename: Uriel
authors.initials: U
authors.lastname: Kuflik
authors.forename: Miriam
authors.initials: M
authors.lastname: Shmuel
authors.forename: Sandrine
authors.initials: S
authors.lastname: Benhamron
authors.forename: Israel
authors.initials: I
authors.lastname: Ringel
authors.forename: Eylon
authors.initials: E
authors.lastname: Yavin
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D002412:Cations / Q000032:analysis / Q000138:chemical synthesis / Q000494:pharmacology / Q000633:toxicity; D018929:Cell Culture Techniques; D004339:Drug Compounding / Q000379:methods; D016503:Drug Delivery Systems; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000378:metabolism / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D008928:Mitochondria / Q000378:metabolism; D058990:Molecular Targeted Therapy; D009943:Organophosphorus Compounds / Q000032:analysis / Q000138:chemical synthesis* / Q000494:pharmacology / Q000633:toxicity; D010455:Peptides / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D011419:Propidium / Q000378:metabolism
chemical_list: D017304:Annexin A5; D051017:Apoptosis Regulatory Proteins; D002412:Cations; D005456:Fluorescent Dyes; D036341:Intercellular Signaling Peptides and Proteins; C535058:KLA peptide; D009943:Organophosphorus Compounds; D010455:Peptides; D011419:Propidium; D016650:Fluorescein-5-isothiocyanate