title: Cellular uptake, distribution and cytotoxicity of the hydrophobic cell penetrating peptide sequence PFVYLI linked to the proapoptotic domain peptide PAD.
abstract: The capacity of cell penetrating peptides (CPPs) to breach biological membranes offers hope for their utilisation as vectors for the delivery of small molecule drugs and macromolecular therapeutics. Using three different cell systems, including primary human cells, we have studied the uptake, subcellular localisation and effect on cell viability of the well characterised octaarginine and the more recently discovered hydrophobic PFVYLI peptide, either alone, or conjugated to the proapoptotic domain peptide PAD (klaklak)(2). Octaarginine and PFVYLI were efficiently endocytosed into cells at 37 degrees C but an ability to translocate directly across the plasma membrane at higher peptide concentrations or when uptake experiments were performed on ice was confined to the cationic variant. Octaarginine- and PFVYLI-PAD conjugates were cytotoxic, with KG1a leukaemia cells being more sensitive than HeLa cells and octaarginine-PAD being the most potent conjugate in both cell lines. The effects of the CPP-PAD conjugates on cell morphology and permeability was rapid suggesting that cytotoxicity is partially mediated at the plasma membrane rather than exclusively through induction of apoptosis at the mitochondria. Primary human leukaemia cells were more similar to KG1a cells than HeLa cells, suggesting the relative sensitivity of leukaemia cells to these peptides could be exploited in vivo.
authors.affiliation: Welsh School of Pharmacy, Cardiff University, Cardiff, CF10 3NB Wales, UK.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Watkins
authors.forename: Paul
authors.initials: P
authors.lastname: Brennan
authors.forename: Christopher
authors.initials: C
authors.lastname: Fegan
authors.forename: Kentaro
authors.initials: K
authors.lastname: Takayama
authors.forename: Ikuhiko
authors.initials: I
authors.lastname: Nakase
authors.forename: Shiroh
authors.initials: S
authors.lastname: Futaki
authors.forename: Arwyn T
authors.initials: AT
authors.lastname: Jones
mesh_terms: D051017:Apoptosis Regulatory Proteins / Q000737:chemistry*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000187:drug effects; D002470:Cell Survival; D003600:Cytosol / Q000378:metabolism; D005434:Flow Cytometry; D006367:HeLa Cells; D006801:Humans; D007202:Indicators and Reagents; D036341:Intercellular Signaling Peptides and Proteins; D007938:Leukemia / Q000378:metabolism; D009842:Oligopeptides / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D010455:Peptides / Q000737:chemistry*; D013696:Temperature
chemical_list: D051017:Apoptosis Regulatory Proteins; D007202:Indicators and Reagents; D036341:Intercellular Signaling Peptides and Proteins; C535058:KLA peptide; D009842:Oligopeptides; D010455:Peptides; C547519:prolyl-phenylalanyl-valyl-tyrosyl-leucyl-isoleucine