title: TLR4 and NLRP3 inflammasome activation in monocytes by N-propionyl cysteaminylphenol-maleimide-dextran (NPCMD).
abstract: BACKGROUND
  N-propionyl cysteaminylphenol-maleimide-dextran (NPCMD) is a toxic tyrosinase substrate developed to treat melanoma.
  
  
  OBJECTIVE
  We investigated the effect of NPCMD on innate immune responses in monocytes.
  
  
  METHODS
  CD14⁺ monocytes and a monocytic cell line, THP-1, were stimulated with NPCMD in vitro. Cytokines in the culture supernatants were determined by ELISA and flow cytometry.
  
  
  RESULTS
  NPCMD stimulated CD14⁺ monocytes and THP-1 cells to secrete TNFα, IL-6 and IL-8, but not IL-10 or IL-12. TNFα secretion from THP-1 cells stimulated with NPCMD was inhibited by addition of an anti-TLR4 mAb in culture. Moreover, NPCMD stimulated production of pro-IL-1β in CD14⁺ monocytes and monocytic cell line THP-1 cells and activated the NLRP3-inflammasome, resulting in production of mature IL-1β. Use of ASC and NLRP3-deficient THP-1 cell lines established involvement of the NLRP3 inflammasome in an IL-1β secretion in treatment with NPCMD. Inhibition of IL-1β secretion by an endocytosis inhibitor, cytochalasin B, and a lysosomal enzyme cathepsin B inhibitor, CA-074 Me, suggested the involvement of lysosomal rupture and leakage of cathepsin B into the cytosol in NLRP3 activation by NPCMD.
  
  
  CONCLUSIONS
  The immunopotentiating effect of NPCMD mediated by TLR4 and NLRP3 inflammasome activation could be useful for eliciting effective adaptive immune responses against melanoma and other tumors.
authors: Department of Immunology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan; Department of Respiratory Medicine, Kawasaki Medical School, Kurashiki, Japan.
authors: Yu
authors: Y
authors: Mizote
authors: Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors: Kazumasa
authors: K
authors: Wakamatsu
authors: Department of Chemistry, Fujita Health University School of Health Sciences, Toyoake, Japan.
authors: Shosuke
authors: S
authors: Ito
authors: Faculty of Health and Welfare, Kawasaki University of Medical Welfare, Kurashiki, Japan.
authors: Akiko
authors: A
authors: Uenaka
authors: Department of Respiratory Medicine, Kawasaki Medical School, Kurashiki, Japan.
authors: Yoshihiro
authors: Y
authors: Ohue
authors: Department of Respiratory Medicine, Kawasaki Medical School, Kurashiki, Japan.
authors: Koji
authors: K
authors: Kurose
authors: Department of Respiratory Medicine, Kawasaki Medical School, Kurashiki, Japan.
authors: Midori
authors: M
authors: Isobe
authors: Department of Chemical Engineering, Faculty of Engineering, Kyusyu University, Fukuoka, Japan.
authors: Akira
authors: A
authors: Ito
authors: Department of Pathology, Sapporo Medical Univeristy School of Medicine, Sapporo, Japan.
authors: Yasuaki
authors: Y
authors: Tamura
authors: Department of Biotechnology, School of Engineering, Nagoya University, Nagoya, Japan.
authors: Hiroyuki
authors: H
authors: Honda
authors: Department of Dermatology, Sapporo Medical Univeristy School of Medicine, Sapporo, Japan.
authors: Toshiharu
authors: T
authors: Yamashita
authors: Meito Sangyo Co., Nagoya, Japan.
authors: Satoshi
authors: S
authors: Nohara
authors: Department of Respiratory Medicine, Kawasaki Medical School, Kurashiki, Japan.
authors: Mikio
authors: M
authors: Oka
authors: Department of Dermatology, Sapporo Medical Univeristy School of Medicine, Sapporo, Japan.
authors: Kowichi
authors: K
authors: Jimbow
authors: Faculty of Health and Welfare, Kawasaki University of Medical Welfare, Kurashiki, Japan. Electronic address: nakayama@mw.kawasaki-m.ac.jp.
authors: Eiichi
authors: E
authors: Nakayama
mesh_terms: D002352:Carrier Proteins / Q000502:physiology*; D045744:Cell Line, Tumor; D003538:Cystamine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003911:Dextrans / Q000494:pharmacology*; D006801:Humans; D058847:Inflammasomes / Q000502:physiology*; D053583:Interleukin-1beta / Q000378:metabolism; D008301:Maleimides / Q000494:pharmacology*; D009000:Monocytes / Q000187:drug effects / Q000502:physiology*; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D010636:Phenols / Q000494:pharmacology*; D051197:Toll-Like Receptor 4 / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D003911:Dextrans; D058847:Inflammasomes; D053583:Interleukin-1beta; D008301:Maleimides; C114098:N-propionyl-4-S-cysteaminylphenol; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D010636:Phenols; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C043592:maleimide; D003538:Cystamine
keywords: Melanogenesis; Nod-like receptors (NLR); Toll-like receptors (TLR); Tyrosinase