title: TLR activation of tumor-associated macrophages from ovarian cancer patients triggers cytolytic activity of NK cells.
abstract: We analyzed the functional outcome of the interaction between tumor-associated macrophages (TAMs) and natural killer (NK) cells. TAMs from ascites of ovarian cancer patients displayed an alternatively activated functional phenotype (M2) characterized by a remarkably high frequency and surface density of membrane-bound IL-18. Upon TLR engagement, TAMs acquired a classically activated functional phenotype (M1), released immunostimulatory cytokines (IL-12, soluble IL-18), and efficiently triggered the cytolytic activity of NK cells. TAMs also induced the release of IFN-γ from NK cells, which however was significantly lower compared with that induced by in vitro-polarized M2 cells. Most tumor-associated NK cells displayed a CD56(bright) , CD16(neg) or CD56(bright) , CD16(dim) phenotype, and very poor cytolytic activities, despite an increased expression of the activation marker CD69. They also showed downregulation of DNAM-1, 2B4, and NTB-A activating receptors, and an altered chemokine receptor repertoire. Importantly however, when appropriately stimulated, NK cells from the patients, including those cells isolated from ascites, efficiently killed autologous TAMs that expressed low, "nonprotective" levels of HLA class I molecules. Overall, our data show the existence of a complex tumor microenvironment in which poorly cytolytic/immature NK cells deal with immunosuppressive tumor-educated macrophages.
authors: Dipartimento di Medicina Sperimentale, Università degli Studi di Genova, Genova, Italy.
authors: Francesca
authors: F
authors: Bellora
authors: Roberta
authors: R
authors: Castriconi
authors: Alessandra
authors: A
authors: Dondero
authors: Anna
authors: A
authors: Pessino
authors: Alessio
authors: A
authors: Nencioni
authors: Giovanni
authors: G
authors: Liggieri
authors: Lorenzo
authors: L
authors: Moretta
authors: Alberto
authors: A
authors: Mantovani
authors: Alessandro
authors: A
authors: Moretta
authors: Cristina
authors: C
authors: Bottino
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D007111:Immunity, Cellular; D007694:Killer Cells, Natural / Q000276:immunology* / Q000473:pathology; D008264:Macrophages / Q000276:immunology* / Q000473:pathology; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000276:immunology*; D010051:Ovarian Neoplasms / Q000276:immunology* / Q000473:pathology; D051193:Toll-Like Receptors / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D016207:Cytokines; D009363:Neoplasm Proteins; D051193:Toll-Like Receptors
keywords: Human; Natural killer cells; Ovarian cancer; Tumor-associated macrophages