Synthesis and In Vitro Testing of New Potent Polyacridine−Melittin Gene Delivery Peptides

Abstract

The combination of a polyacridine peptide modified with a melittin fusogenic peptide results in a potent gene transfer agent. Polyacridine peptides of the general formula (Acr-X)n-Cys were prepared by solid phase peptide synthesis, where Acr is Lys modified on its ε-amine with acridine, X is Arg, Leu or Lys and n is 2, 3 or 4 repeats. The Cys residue was modified by either a maleimide-melittin or a thiolpyridine-Cys-melittin fusogenic peptide resulting in reducible or non-reducible polyacridine-melittin peptides. Hemolysis assays established that polyacridine-melittin peptides retained their membrane lytic potency relative to melittin at pH 7.4 and 5. When combined with plasmid DNA, the membrane lytic potency of polyacridine-melittin peptides was neutralized. Gene transfer experiments in multiple cell lines established polyacridine-melittin peptides mediate expression as efficiently as PEI. The expression was very dependent upon a disulfide bond linking polyacridine to melittin. The gene transfer was most efficient when X is Arg and n is 3 or 4 repeats. These studies establish polyacridine peptides as a novel DNA binding anchor peptide.

Dual secured nano-melittin for the safe and effective eradication of cancer cells

“…5), which is consistent with the observation of others. 15 SSNS at the concentration of 0.5 and 1.0 μM displayed considerably higher hemolytic activities in acidic pH than that in pH 7.4, suggesting the release of free melittin at low pH, which was consistent with our FRET observation in Fig. 3B.…”

PEG length and chemical linkage controls polyacridine peptide DNA polyplex pharmacokinetics, biodistribution, metabolic stability and in vivo gene expression

“…9-Phenoxyacridine and Fmoc-Lysine(Acridine)-OH were prepared as recently reported [24, 25]. The polyacridine peptides defined in Figure 1 and Table 1S were prepared by solid phase peptide synthesis on a 30 μmol scale using an APEX 396 synthesizer (Advanced ChemTech, Louisville, KY, USA) with standard Fmoc procedures.…”

“Evolving nanoparticle gene delivery vectors for the liver: What has been learned in 30 years”

“…To increase the affinity of short peptides for DNA, several groups have incorporated multiple intercalators into vectors to hydrophobically bind to DNA [97][98][99] The intercalator acridine, can be most easily added to the side chain of lysine, then installed into a peptide at any desired location during solid phase peptide synthesis [61,100]. Polyacridine peptides ( Fig.…”

“…When co-polymerized with a PEG-peptide and glycopeptide, the resulting PEGylated glycoprotein protected DNA in the circulation and produced measurable gene expression in the liver of mice upon hydrodynamic stimulation [60]. In addition, melittin was attached to a polyacridine peptide through either a reducible disulfide linkage or a non-reducible maleimide linkage [220]. Melittin bioconjugates were able to mediate potent in vitro transfect in vitro with potency equal to PEI.…”