title: In vitro uptake and stability study of pVEC and its all-D analog.
abstract: A key step in the development of new hydrophilic pharmaceuticals is to get them through biological barriers. Cell-penetrating peptides, CPPs, have been shown previously to enter cells both in vitro and in vivo by a non-endocytotic mechanism and to be able to carry large cargo molecules with them. Recently, we showed that a small peptide, pVEC, from murine vascular endothelial cadherin, has the characteristics to be classified as a protein derived CPP. Here we have further investigated pVEC together with its all-D analog for cellular uptake, intra- and extracellular stability, and their enzymatic degradation. The two peptides, pVEC and all-D pVEC, translocate into aortic endothelial cells and murine fibroblasts by a non-endocytotic mechanism. In phosphate buffer, pVEC remains intact while the C-terminal lysine is quickly removed in human serum and serum-containing media. Both pVEC and pVEC without the C-terminal Lys were detected by mass spectrometry inside the two cell types tested. The pVEC half-life is 10.5 min in phosphate buffer containing 10 units of trypsin and 44.6 min in phosphate buffer containing 4.2 units of carboxypeptidase A and 18 units of carboxypeptidase B. In contrast topVEC, the all-D analog remains intact in serum and resists enzymatic degradation.
authors.affiliation: Department of Neurochemistry and Neurotoxicology, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Elmquist
authors.forename: Ulo
authors.initials: U
authors.lastname: Langel
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism; D002352:Carrier Proteins / Q000493:pharmacokinetics*; D002460:Cell Line; D002463:Cell Membrane Permeability; D004337:Drug Carriers / Q000737:chemistry / Q000493:pharmacokinetics; D004355:Drug Stability; D010450:Endopeptidases / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005456:Fluorescent Dyes; D006801:Humans; D051379:Mice; D010446:Peptide Fragments / Q000737:chemistry / Q000493:pharmacokinetics*; D010455:Peptides / Q000737:chemistry / Q000493:pharmacokinetics*; D013237:Stereoisomerism
chemical_list: D002352:Carrier Proteins; D004337:Drug Carriers; D005456:Fluorescent Dyes; D010446:Peptide Fragments; D010455:Peptides; C437783:pVEC peptide; D010450:Endopeptidases