Development of a cell penetrating peptide library

Tiffani N Anderson, Purdue University

Abstract

Cell permeability remains a major obstacle for the delivery of therapeutic agents into the cell. The development and use of cell penetrating peptides, rich in basic amino acids, have become an attractive option as molecular transporters. These types of peptides have been shown to be minimally toxic to a variety of different cell lines as well as the ability to deliver a wide selection of cargoes including nucleic acids, proteins, imaging agents and nanoparticles. Our group has developed a series of novel CPPs which adopt a rigid secondary structure referred to as cationic amphiphilic polyproline helices. These peptides have been designed to display both hydrophilic and hydrophobic moieties along a polyproline type II helix in an amphiphilic manner. The peptides have been synthesized to posses either hydrophilic/hydrophobic residues through O-alkylation of hydroxyproline. Previous work has shown that CAPHs displaying guanidinium groups have superior uptake to that containing amine groups. Additionally, it has been shown that an increase in the number of positive charges within the peptide also facilitate cellular internalization. Dramatic effects in cellular uptake have also been observed for CAPHs bearing different hydrophobic groups. To further explore the hydrophobic effects of CAPHs, a library composed of aliphatic and aromatic peptides were synthesized. The methodology for the synthesis of these peptides was based upon synthesis of an amine-protected hydroxyproline monomer that could be subjected to on-resin deprotection following peptide synthesis. In order to probe the effects that hydrocarbon chains play in cellular uptake, three, unique, aliphatic peptides were prepared ranging from 6-10 methylene units. Furthermore, to determine whether there is a correlation between LogP and cellular internalization, peptides were synthesized with functionalized aromatic moieties. The functional groups of choice were an electron-donating group, methoxy (OCH3), an electron-withdrawing group, nitro (NO2) and a neutral group (H). Cellular internalization was evaluated by flow cytometry and cellular viability was determined via MTT assays.

Degree

M.S.

Advisors

Chmielewski, Purdue University.

Subject Area

Biochemistry

COinS