title: Toll-like receptor 4 gene polymorphism influences dendritic cell in vitro function and clinical outcomes in vaccinated melanoma patients.
abstract: Toll-like receptor 4 (TLR4) is expressed on dendritic cells (DCs), sensing environmental danger molecules that induce their activation and maturation. Recently, we reported a method for the production of therapeutic DCs against melanoma, called tumor antigen-presenting cells (TAPCells), using a heat-shocked allogeneic melanoma cell lysate (TRIMEL) as an activation factor and antigen provider. Since TRIMEL contains endogenous TLR4 ligands, we evaluated the role of TLR4 in TAPCells differentiation by antibody neutralization and the association of a Tlr4 polymorphism (896A/G) (Asp299Gly), determined by PCR-RFLP, with the in vitro activation capacity and the clinical outcome of TAPCells-vaccinated patients. Antibody blocking of monocyte TLR4 inhibited surface expression, determined by flow cytometry, of the major histocompatibility complex class I, CCR7, CD80, CD83 and CD86 on TAPCells, reduced interleukin (IL)-6 and tumor necrosis factor -α gene expression evaluated by qRT-PCR, and also inhibited the TAPCells-mediated interferon-γ (IFN-γ) secretion of melanoma-specific CD8(+) T cells determined by ELISpot (p < 0.01). Moreover, CD8(+) T-cell activation capacity was significantly reduced in TAPCells bearing the TLR4 Asp299Gly receptor (p < 0.05). Finally, TAPCells-vaccinated stage-IV melanoma patients bearing the Tlr4 896G allele showed a shortened post-therapy median survival rate compared with those carrying the Tlr4 896A allele (p < 0.05; log-rank test). Our results indicate that TLR4 is a key receptor for the tumor lysate-mediated in vitro generation of clinically efficient antigen-presenting cells. Further analysis of patients included in different vaccine protocols is necessary for definitively establishing a role for TLR4 polymorphism in clinical responses.
authors.affiliation: Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, 8380453, Santiago Chile, Chile. tittarelli@gmail.com
authors.forename: Andrés
authors.initials: A
authors.lastname: Tittarelli
authors.forename: Fermín E
authors.initials: FE
authors.lastname: González
authors.forename: Cristián
authors.initials: C
authors.lastname: Pereda
authors.forename: Gabriela
authors.initials: G
authors.lastname: Mora
authors.forename: Leonel
authors.initials: L
authors.lastname: Muñoz
authors.forename: Carlos
authors.initials: C
authors.lastname: Saffie
authors.forename: Tamara
authors.initials: T
authors.lastname: García
authors.forename: David
authors.initials: D
authors.lastname: Díaz
authors.forename: Cristián
authors.initials: C
authors.lastname: Falcón
authors.forename: Marcela
authors.initials: M
authors.lastname: Hermoso
authors.forename: Mercedes N
authors.initials: MN
authors.lastname: López
authors.forename: Flavio
authors.initials: F
authors.lastname: Salazar-Onfray
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057134:Antibodies, Neutralizing / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000276:immunology / Q000627:therapeutic use*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008545:Melanoma / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology; D011110:Polymorphism, Genetic; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000276:immunology / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D051197:Toll-Like Receptor 4 / Q000235:genetics* / Q000276:immunology; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D057134:Antibodies, Neutralizing; D019496:Cancer Vaccines; D016207:Cytokines; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4