TLR4 and NLRP3 inflammasome activation in monocytes by N-propionyl cysteaminylphenol-maleimide-dextran (NPCMD).
J Dermatol Sci 2013;
73:209-15. [PMID:
24315204 DOI:
10.1016/j.jdermsci.2013.11.006]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/07/2013] [Accepted: 11/07/2013] [Indexed: 10/26/2022]
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.
CONCLUSION
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.
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