title: Quinoline derivatives are therapeutic candidates for transmissible spongiform encephalopathies.
abstract: We previously reported that quinacrine inhibited the formation of an abnormal prion protein (PrPres), a key molecule in the pathogenesis of transmissible spongiform encephalopathy, or prion disease, in scrapie-infected neuroblastoma cells. To elucidate the structural aspects of its inhibiting action, various chemicals with a quinoline ring were screened in the present study. Assays of the scrapie-infected neuroblastoma cells revealed that chemicals with a side chain containing a quinuclidine ring at the 4 position of a quinoline ring (represented by quinine) inhibited the PrPres formation at a 50% inhibitory dose ranging from 10(-1) to 10(1) micro M. On the other hand, chemicals with a side chain at the 2 position of a quinoline ring (represented by 2,2'-biquinoline) more effectively inhibited the PrPres formation at a 50% inhibitory dose ranging from 10(-3) to 10(-1) micro M. A metabolic labeling study revealed that the action of quinine or biquinoline was not due to any alteration in the biosynthesis or turnover of normal prion protein, whereas surface plasmon resonance analysis showed a strong binding affinity of biquinoline with a recombinant prion protein. In vivo studies revealed that 4-week intraventricular infusion of quinine or biquinoline was effective in prolonging the incubation period in experimental mouse models of intracerebral infection. The findings suggest that quinoline derivatives with a nitrogen-containing side chain have the potential of both inhibiting PrPres formation in vitro and prolonging the incubation period of infected animals. These chemicals are new candidates for therapeutic drugs for use in the treatment of transmissible spongiform encephalopathies.
authors.affiliation: Department of Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Murakami-Kubo
authors.forename: Katsumi
authors.initials: K
authors.lastname: Doh-Ura
authors.forename: Kensuke
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawatake
authors.forename: Kensuke
authors.initials: K
authors.lastname: Sasaki
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Kira
authors.forename: Shigeru
authors.initials: S
authors.lastname: Ohta
authors.forename: Toru
authors.initials: T
authors.lastname: Iwaki
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007276:Injections, Intraventricular; D051379:Mice; D008822:Mice, Transgenic; D009447:Neuroblastoma; D018620:PrPSc Proteins / Q000187:drug effects* / Q000378:metabolism; D017096:Prion Diseases / Q000188:drug therapy*; D011796:Quinacrine / Q000494:pharmacology; D011803:Quinine / Q000031:analogs & derivatives / Q000494:pharmacology; D011804:Quinolines / Q000737:chemistry* / Q000494:pharmacology / Q000627:therapeutic use*; D013329:Structure-Activity Relationship; D020349:Surface Plasmon Resonance; D014407:Tumor Cells, Cultured
chemical_list: D018620:PrPSc Proteins; D011804:Quinolines; D011803:Quinine; D011796:Quinacrine