title: Interaction of cepharanthine with immobilized heat shock protein 90α (Hsp90α) and screening of Hsp90α inhibitors.
abstract: Heat shock protein 90α (Hsp90α) immobilized on aminopropyl silica gels was prepared via the N- or C-terminal, which was termed Hsp90α-NT or Hsp90α-CT, respectively. Binding interactions of biscoclaurine alkaloids (cepharanthine (CEP), berbamine (BBM), isotetrandrine (ITD), and cycleanine (CCN)) with Hsp90α were examined using the Hsp90α-NT or -CT columns by frontal and zonal chromatography studies. The dissociation constants of CEP, BBM, ITD, and CCN to Hsp90α-NT were estimated to be 5.3, 18.6, 46.3, and 159 μM, respectively, by frontal chromatography techniques. Similar results were obtained with the Hsp90α-CT column. These data suggest that these biscoclaurine alkaloids interact with the middle domain of Hsp90α. This was confirmed by demonstrating that CEP competed with endothelial nitric oxide synthase at the middle domain of Hsp90α, where it was shown to have a dissociation constant of 15 nM. Furthermore, the Hsp90α-NT column was applied for preliminary screening of natural Hsp90α inhibitors by zonal chromatography studies.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68, Nishinomiya 663-8179, Japan. haginaka@mukogawa-u.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Haginaka
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kitabatake
authors.forename: Iyo
authors.initials: I
authors.lastname: Hirose
authors.forename: Hisami
authors.initials: H
authors.lastname: Matsunaga
authors.forename: Ruin
authors.initials: R
authors.lastname: Moaddel
mesh_terms: D000470:Alkaloids / Q000032:analysis / Q000378:metabolism; D044182:Benzylisoquinolines / Q000032:analysis* / Q000378:metabolism; D002846:Chromatography, Affinity; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D055767:Immobilized Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D007546:Isoquinolines / Q000032:analysis / Q000378:metabolism; D007700:Kinetics; D011485:Protein Binding; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D052117:Benzodioxoles
chemical_list: D000470:Alkaloids; D044182:Benzylisoquinolines; D018841:HSP90 Heat-Shock Proteins; D055767:Immobilized Proteins; D007546:Isoquinolines; D011994:Recombinant Proteins; C533585:HSP90AA2P protein, human; C009438:tetrandrine; C037098:cycleanine; C006947:cepharanthine; D052117:Benzodioxoles; C027870:berbamine