A non-covalent peptide-based carrier for in vivo delivery of DNA mimics

Abstract

The dramatic acceleration in identification of new nucleic-acid-based therapeutic molecules has provided new perspectives in pharmaceutical research. However, their development is limited by their poor cellular uptake and inefficient trafficking. Here we describe a short amphipathic peptide, Pep-3, that combines a tryptophan/phenylalanine domain with a lysine/arginine-rich hydrophilic motif. Pep-3 forms stable nano-size complexes with peptide-nucleic acid analogues and promotes their efficient delivery into a wide variety of cell lines, including primary and suspension lines, without any associated cytotoxicity. We demonstrate that Pep-3-mediated delivery of antisense-cyclin B1-charged-PNA blocks tumour growth in vivo upon intratumoral and intravenous injection. Moreover, we show that PEGylation of Pep-3 significantly improves complex stability in vivo and consequently the efficiency of antisense cyclin B1 administered intravenously. Given the biological characteristics of these vectors, we believe that peptide-based delivery technologies hold a true promise for therapeutic applications of DNA mimics.

Peptides for nucleic acid delivery

“…However, a few interesting studies have been published along these lines. For example, Morris et al used the amphipathic Pep-3 peptide for vectorization of chemically modified charged PNA (HypNa-pPNA) [87]. Although the formed nanoparticles displayed high activity in cell culture, when administered IT to PC3 tumor xenograft mice, Pep-3/ HypNa-pPNA nanoparticles had limited activity following systemic delivery.…”

“…To overcome this, the authors sought to further introduce PEG-modification to Pep-3 peptide. These PEG-carrying formulations provided significantly enhanced accumulation in the tumor tissue upon systemic administration and induced substantial tumor growth inhibition [87].…”

Peptides for Specific Intracellular Delivery and Targeting of Nanoparticles: Implications for Developing nanoparticle-mediated Drug Delivery

“…The synthesized peptide is acetylated at its N-terminus and bears a cysteamide group at its C-terminus as both modifications have been shown to be important for peptide stability and efficient cellular uptake [104,105]. Iterative functional studies of the Pep-1 sequence have determined that all four of the cationic lysine residues within the hydrophilic domain are required for optimal membrane interaction and that the presence of the proline within the spacer domain is essential for maintaining the required flexibility between the hydrophobic and hydrophilic domains [106]. Lastly, the Pep-1 peptide adopts a helical structure and the presence of the tryptophan-phenylalanine tandem on one side of the helix is required for cell membrane interaction and membrane disorganization functions [107].…”

Self-assembled Structures from Amphiphilic Peptides

“…The latter is predominantly occupied by charged and polar amino acids; these are: arginine (R), [6,7] histidine (H), [7,8] lysine (K), [9][10][11][12][13][14][15] aspartic acid (D), [16,17] glutamic acid (E), [11,18] serine (S), threonine (T), asparagine (N), glutamine (Q), and cysteine (C). [13] The design of the hydrophobic part is based on amino acids with neutral and nonpolar side-chains such as glycine (G), [16] alanine (A), [15,19] valine (V), [17,20] leucine (L), [9,17] isoleucine (I), [21] methionine (M), phenylalanine (F), [22,23] tyrosine (Y), and tryptophan (W). [7,[10][11][12][13][14]23] Depending on the hydrophobic to hydrophilic ratio and the sequence, various self-assembled structures can be constructed -as indicated in the associated references for the above amino acids -although the hydrophobicity is moderated by the polar character of the peptide's backbone.…”

“…[13] The design of the hydrophobic part is based on amino acids with neutral and nonpolar side-chains such as glycine (G), [16] alanine (A), [15,19] valine (V), [17,20] leucine (L), [9,17] isoleucine (I), [21] methionine (M), phenylalanine (F), [22,23] tyrosine (Y), and tryptophan (W). [7,[10][11][12][13][14]23] Depending on the hydrophobic to hydrophilic ratio and the sequence, various self-assembled structures can be constructed -as indicated in the associated references for the above amino acids -although the hydrophobicity is moderated by the polar character of the peptide's backbone.…”