title: Synthesis and preliminary evaluation of poly(amidoamine)-melittin conjugates as endosomolytic polymers and/or potential anticancer therapeutics.
abstract: The pH-responsive poly(amidoamine)s (PAAs) have been previously described. Whereas ISA23 enhances transfection in vitro and ISA1 promotes the cytosolic delivery of the non-permeant toxins this process shows poor efficiency. The aim of this study was to prepare and evaluate PAA conjugates containing the membrane disrupting peptide melittin (MLT). It was hypothesised that PAA conjugation would reduce the haemolytic activity of MLT at pH 7.4, however, upon delivery to tumours by the EPR effect, the polymer would uncoil in an acidic environment exposing MLT and allowing it to interact with membranes. PAA-MLT conjugates were prepared using MLT as a comonomer together with bis-acryloylpiperazine, 2-methylpiperazine and bis-hydroxyethylethylenediamine (ISA1-like), or bis-acrylamidoacetic acid and 2-methylpiperazine (ISA23-like). The melittin content of the conjugates was 6-19% (w/w). Although ISA1-MLT improved gelonin delivery compared to the parent polymer ISA1 (alpha 13-fold increase) and showed pH-dependent haemolytic activity at a polymer concentration of 0.05 mg/ml, this conjugate also displayed high haemolytic activity at pH 7.4.In contrast, ISA23-MLT like the parent compound ISA23 did not deliver gelonin. However, this conjugate could have potential as a novel polymeric anticancer conjugate due to its lack of haemolytic activity at pH 7.4 and retention of cytotoxicity.
authors: Centre for Polymer Therapeutics, Welsh, School of Pharmacy Redwood Building, Cardiff University, King Edward VII Avenue, Cardiff CF10 3XF, UK.
authors: Nathalie
authors: N
authors: Lavignac
authors: Michelle
authors: M
authors: Lazenby
authors: Jacopo
authors: J
authors: Franchini
authors: Paolo
authors: P
authors: Ferruti
authors: Ruth
authors: R
authors: Duncan
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage*; D016503:Drug Delivery Systems; D011992:Endosomes / Q000378:metabolism*; D006461:Hemolysis / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008555:Melitten / Q000008:administration & dosage* / Q000494:pharmacology; D010879:Piperazines / Q000008:administration & dosage* / Q000138:chemical synthesis; D011073:Polyamines / Q000008:administration & dosage* / Q000138:chemical synthesis; D011108:Polymers / Q000008:administration & dosage* / Q000138:chemical synthesis
chemical_list: D000970:Antineoplastic Agents; C496056:ISA23 polymer; D010879:Piperazines; D011073:Polyamines; D011108:Polymers; D008555:Melitten