ABSTRACT
[reaction: see text] Nine fluorescently labeled structurally varied polyguanidino dendrimers based on diamino acid monomeric units were individually synthesized in an efficient, scalable sequence using a trifluoroacetamide protecting group-perguanidinylation strategy. While the dendrimers varied significantly in their ability to enter a human lymphocyte cell line, the best transporters out-performed an oligoarginine reference standard.
Subject(s)
Amino Acid Transport Systems/chemical synthesis , Dendrimers/chemical synthesis , Fluorescent Dyes/chemical synthesis , Guanidine/chemistry , Polymers/chemical synthesis , Amino Acid Transport Systems/chemistry , Amino Acid Transport Systems/pharmacokinetics , Cell Line , Dendrimers/chemistry , Dendrimers/pharmacokinetics , Fluorescent Dyes/chemistry , Fluorescent Dyes/pharmacokinetics , Humans , Lymphocytes/drug effects , Lymphocytes/metabolism , Molecular Structure , Polymers/chemistry , Polymers/pharmacokinetics , Protein Transport/drug effectsABSTRACT
Molecular transporters have the ability to deliver drugs and probe molecules into cells and tissues irrespective of their physical properties. We now report the design, synthesis, and biological evaluation of a new family of molecular transporters, guanidinylated oligocarbamates that enable exceptionally efficient uptake into cells and tissues. The synthesis features a solid-phase stepwise oligomerization to obtain the oligocarbamates and a single step perguanidinylation for the facile introduction of up to nine guanidinium groups. The oligocarbamate 9-mer is found to be among the most efficient transporters known, entering cells faster than even d-Arg9 and HIV-1 Tat49-57. Significantly, this new family of transporters also enables uptake into the formidable skin barrier of a probe molecule that by itself does not penetrate skin.
Subject(s)
Carbamates/chemical synthesis , Carbamates/pharmacokinetics , Drug Carriers/chemical synthesis , Drug Carriers/pharmacokinetics , Drug Delivery Systems/methods , Animals , Biotin/administration & dosage , Biotin/pharmacokinetics , Drug Design , Guanidine/chemistry , Humans , Jurkat Cells/metabolism , Mice , Skin/metabolismABSTRACT
Short oligomers of arginine, either alone or when conjugated to therapeutic agents or large biopolymers, have been shown to cross readily a variety of biological barriers (e.g., lipid bilayers and epithelial tissue). Molecular modeling suggests that only a subset of the side chain guanidinium groups of these transporters might be required for transport involving contact with a common surface such as a plasma membrane or cell surface receptor. To evaluate this hypothesis, a series of decamers were prepared that incorporated seven arginines and three nonarginine residues. Several of these mixed decamers were comparable to the all arginine decamer in their ability to enter cells. More significantly, these decamers containing seven arginines performed almost without exception better than heptaarginine itself, suggesting that spacing between residues is also important for transport. The influence of spacing was more fully evaluated with a library of oligomers incorporating seven arginines separated by one or more nonconsecutive, non-alpha-amino acids. This study led to the identification of a new series of highly efficient molecular transporters.
