title: Enhanced cellular uptake of short polyarginine peptides through fatty acylation and cyclization.
abstract: Many of the reported arginine-rich cell-penetrating peptides (CPPs) for the enhanced delivery of drugs are linear peptides composed of more than seven arginine residues to retain the cell penetration properties. Herein, we synthesized a class of nine polyarginine peptides containing 5 and 6 arginines, namely, R5 and R6. We further explored the effect of acylation with long chain fatty acids (i.e., octanoic acid, dodecanoic acid, and hexadecanoic acid) and cyclization on the cell penetrating properties of the peptides. The fluorescence-labeled acylated cyclic peptide dodecanoyl-[R5] and linear peptide dodecanoyl-(R5) showed approximately 13.7- and 10.2-fold higher cellular uptake than that of control 5,6-carboxyfluorescein, respectively. The mechanism of the peptide internalization into cells was found to be energy-dependent endocytosis. Dodecanoyl-[R5] and dodecanoyl-[R6] enhanced the intracellular uptake of a fluorescence-labeled cell-impermeable negatively charged phosphopeptide (F'-GpYEEI) in human ovarian cancer cells (SK-OV-3) by 3.4-fold and 5.5-fold, respectively, as shown by flow cytometry. The cellular uptake of F'-GpYEEI in the presence of hexadecanoyl-[R5] was 9.3- and 6.0-fold higher than that in the presence of octanoyl-[R5] and dodecanoyl-[R5], respectively. Dodecanoyl-[R5] enhanced the cellular uptake of the phosphopeptide by 1.4-2.5-fold higher than the corresponding linear peptide dodecanoyl-(R5) and those of representative CPPs, such as hepta-arginine (CR7) and TAT peptide. These results showed that a combination of acylation by long chain fatty acids and cyclization on short arginine-containing peptides can improve their cell-penetrating property, possibly through efficient interaction of rigid positively charged R and hydrophobic dodecanoyl moiety with the corresponding residues in the cell membrane phospholipids.
authors: Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States.
authors: Donghoon
authors: D
authors: Oh
authors: Amir
authors: A
authors: Nasrolahi Shirazi
authors: Kevin
authors: K
authors: Northup
authors: Brian
authors: B
authors: Sullivan
authors: Rakesh Kumar
authors: RK
authors: Tiwari
authors: Marco
authors: M
authors: Bisoffi
authors: Keykavous
authors: K
authors: Parang
mesh_terms: D000215:Acylation; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D049109:Cell Proliferation; D057846:Cell-Penetrating Peptides; D003500:Cyclization; D004337:Drug Carriers / Q000737:chemistry; D004705:Endocytosis; D005227:Fatty Acids / Q000737:chemistry*; D005260:Female; D005452:Fluoresceins / Q000737:chemistry; D057809:HEK293 Cells; D006801:Humans; D018613:Microscopy, Confocal; D010051:Ovarian Neoplasms / Q000188:drug therapy; D010455:Peptides / Q000737:chemistry / Q000493:pharmacokinetics*; D010456:Peptides, Cyclic / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D010748:Phosphopeptides / Q000737:chemistry; D014364:Tryptophan / Q000737:chemistry
chemical_list: D057846:Cell-Penetrating Peptides; D004337:Drug Carriers; D005227:Fatty Acids; D005452:Fluoresceins; D010455:Peptides; D010456:Peptides, Cyclic; D010743:Phospholipids; D010748:Phosphopeptides; C015462:polyarginine; C024098:6-carboxyfluorescein; D014364:Tryptophan