title: Chloroquine and amphipathic peptide helices show synergistic transfection in vitro.
abstract: A pH-responsive peptide fragment modelled on the influenza virus haemagglutinin (INF7-SGSC) can promote the transfectional activity of poly(L)-lysine (pLL)/DNA complexes against 293 cells. Chloroquine also promotes transfection, but the combination of INF7-SGSC and chloroquine gives an increased, synergistic, transfectional activity. This was unexpected since the supposed modes of action of these two agents are expected to be incompatible. Microinjection of pLL/DNA complexes into the cytoplasm of Xenopus oocytes produced greater gene expression than microinjection of free DNA, possibly reflecting nuclear-homing or protection from degradation by cytoplasmic nucleases. However, pretreatment of complexes with INF7-SGSC (but not chloroquine) before cytoplasmic microinjection promoted gene expression still further. When pLL/DNA complexes were injected directly into the nucleus, INF7-SGSC again increased gene expression. The mechanism of post-endosomal action of INF7-SGSC is unknown, but could reflect its polyanionic nature, possibly enhancing intranuclear dissociation of the complexes. Whatever the mechanism, it appears that INF7-SGSC mediates two effects-one probably endosomal and the second post-endosomal, the latter showing a synergistic transfection interaction with chloroquine.
authors.affiliation: CRC Institute for Cancer Studies, University of Birmingham, School of Medicine, Edgbaston, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Wolfert
authors.forename: L W
authors.initials: LW
authors.lastname: Seymour
mesh_terms: D000818:Animals; D002738:Chloroquine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D015870:Gene Expression; D017930:Genes, Reporter; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008845:Microinjections; D010446:Peptide Fragments / Q000494:pharmacology*; D011107:Polylysine / Q000235:genetics; D014162:Transfection / Q000187:drug effects*; D014981:Xenopus
chemical_list: D010446:Peptide Fragments; D011107:Polylysine; D002738:Chloroquine