Natural Killer Cell-mediated Effects Research Articles

Increased donor inhibitory KIR are associated with reduced GVHD and improved survival following HLA-matched unrelated donor HCT in paediatric acute leukaemia.

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated effects after haematopoietic stem cell transplantation (HCT). Previous work has shown that accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity in the adult transplant setting. Paediatric acute leukaemia patients were retrospectively analysed, and KIR-KIRL combinations and maximal inhibitory KIR ligand (IM-KIR) scores were determined. Clinical outcomes were examined using a series of graphs depicting clinical events and endpoints. The graph methodology demonstrated that prognostic variables significant in the occurrence of specific clinical endpoints remained significant for relevant downstream events. KIR-KIRL combinations were significantly predictive for reduced grade 3-4 aGVHD likelihood, in patients transplanted with increased inhibitory KIR gene content and IM-KIR = 5 scores. Improvements were also observed in associated outcomes for both ALL and AML patients, including relapse-free survival, GRFS and overall survival. This study demonstrates that NK cell KIR HLA interactions may be relevant to the paediatric acute leukaemia transplant setting. Reduction in aGVHD suggests KIR effects may extend beyond NK cells. Moving forward clinical trials utilizing donors with a higher iKIR should be considered for URD HCT in paediatric recipients with acute leukaemia to optimize clinical outcomes.

Hepatitis D infection induces IFN-β-mediated NK cell activation and TRAIL-dependent cytotoxicity.

The co-infection of hepatitis B (HBV) patients with the hepatitis D virus (HDV) causes the most severe form of viral hepatitis and thus drastically worsens the course of the disease. Therapy options for HBV/HDV patients are still limited. Here, we investigated the potential of natural killer (NK) cells that are crucial drivers of the innate immune response against viruses to target HDV-infected hepatocytes. We established in vitro co-culture models using HDV-infected hepatoma cell lines and human peripheral blood NK cells. We determined NK cell activation by flow cytometry, transcriptome analysis, bead-based cytokine immunoassays, and NK cell-mediated effects on T cells by flow cytometry. We validated the mechanisms using CRISPR/Cas9-mediated gene deletions. Moreover, we assessed the frequencies and phenotype of NK cells in peripheral blood of HBV and HDV superinfected patients. Upon co-culture with HDV-infected hepatic cell lines, NK cells upregulated activation markers, interferon-stimulated genes (ISGs) including the death receptor ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), produced interferon (IFN)-γ and eliminated HDV-infected cells via the TRAIL-TRAIL-R2 axis. We identified IFN-β released by HDV-infected cells as an important enhancer of NK cell activity. In line with our in vitro data, we observed activation of peripheral blood NK cells from HBV/HDV co-infected, but not HBV mono-infected patients. Our data demonstrate NK cell activation in HDV infection and their potential to eliminate HDV-infected hepatoma cells via the TRAIL/TRAIL-R2 axis which implies a high relevance of NK cells for the design of novel anti-viral therapies.

Direct and natural killer cell-mediated antitumor effects of CB1 receptor antagonist rimonabant in human glioblastoma.

Event Abstract Back to Event Direct and natural killer cell-mediated antitumor effects of CB1 receptor antagonist rimonabant in human glioblastoma. Elena Ciaglia1, 2*, Simona Pisanti1, 2, Paola Picardi2, Chiara Laezza3, Giovanni Torelli4, Patrizia Gazzerro2 and Maurizio Bifulco1, 2 1 University of Salerno, Medicine and Surgery, Italy 2 University of Salerno, Pharmacy, Italy 3 IEOS CNR, Institute of Endocrinology and Experimental Oncology, Italy 4 "G.Rummo" Hospital, Neurosurgery, Italy The failure of conventional cancer therapy renders glioblastoma (GBM) an attractive target for novel combined chemoimmunotherapeutic strategies. In the last years the pharmacological tuning of (endo)cannabinoid system has constituted a promising tool for the management of GBM patients. In this study we investigated the therapeutic exploitation of CB1 inactivation with regard to direct and NK cell-mediated effects against GBM. We show for the first time that Rimonabant treatment inhibited growth and viability of a panel of human glioma cell lines in both monolayer culture and 3D Minitumour spheroid models by decreasing the expression levels of Bcl-2, Bcl-XL and Survivin anti-apoptotic factors and concomitantly by inducing tumor necrosis factor (TNF)-related apoptosis-inducing ligand death receptor 4 (DR4) and DR5. Interestingly Rimonabant lead also to functional expression of MHC class I-related chain A and B (MICA/B) on surface of malignant p53mut U251MG and T98G glioma cell lines but not on normal human astrocyte (NHA). This make GBM cells potent targets for natural killer (NK) cell mediated recognition through a NKG2D restricted mechanism, thus stimulating cytotoxicity and IFN-Ƴ production of cocultured NK cells. This last effect relies on the inhibition of STAT3 signaling, whose constitutive activity has been previously seen to promote escape to NKG2D-mediated immune-surveillance. Our study suggests that, in addition to the direct cytotoxic effect, Rimonabant also can make GBM immunovisible priming it for NK cell antitumor reactivity. Taking into account that the brain tumor microenvironment is more commonly associated to CD56-positive NK cells, GBM patients may benefit from Rimonabant treatment. Acknowledgements This study was supported by Associazione Italiana Ricerca sul Cancro (AIRC; Investigator Grant IG 13312 to M.B.) E.Ciaglia was supported by a fellowship from FIRC -Fondazione Italiana Ricerca sul Cancro. Keywords: CB1 receptor, NK cell, Glioblastoma, ULBP, STAT3 Transcription Factor Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Translational immunology and immune intervention Citation: Ciaglia E, Pisanti S, Picardi P, Laezza C, Torelli G, Gazzerro P and Bifulco M (2013). Direct and natural killer cell-mediated antitumor effects of CB1 receptor antagonist rimonabant in human glioblastoma.. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00048 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Elena Ciaglia, University of Salerno, Medicine and Surgery, Baronissi (Salerno), 84081, Italy, eciaglia@unisa.it Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Elena Ciaglia Simona Pisanti Paola Picardi Chiara Laezza Giovanni Torelli Patrizia Gazzerro Maurizio Bifulco Google Elena Ciaglia Simona Pisanti Paola Picardi Chiara Laezza Giovanni Torelli Patrizia Gazzerro Maurizio Bifulco Google Scholar Elena Ciaglia Simona Pisanti Paola Picardi Chiara Laezza Giovanni Torelli Patrizia Gazzerro Maurizio Bifulco PubMed Elena Ciaglia Simona Pisanti Paola Picardi Chiara Laezza Giovanni Torelli Patrizia Gazzerro Maurizio Bifulco Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

A Potent Thymic Function Is Associated with a Low Risk of Relapse In Leukemia Patients Treated with Haploidentical Stem Cell Transplantation

AbstractAbstract 1258Hematopoietic Stem Cell Transplantation (HSCT) is an effective treatment for many malignant and non malignant diseases in children. Since less than 30% of the patients have an HLA identical related donor, alternative donor/sources of Hematopoietic Stem Cells need to be considered, such as unrelated bone marrow (BM) and Cord Blood (CB) donors or HLA-haploidentical related donors. However, these types of HSCT are associated with a significant delay in immune reconstitution that favors both a high incidence of opportunistic infection and, in the absence of an alloreactive, natural killer cell-mediated effect, disease relapse. Indeed, T-cell depletion of the allograft in the haploidentical setting or T-cell naivety in CB, as well as HLA-disparity and use of serotherapy before HSCT, contribute to this impaired immune reconstitution. In view of the role played by the thymus in immune reconstitution post-allogeneic HSCT, it would be informative to compare thymic-dependent immune reconstitution after these types of HSCT.We have studied immune reconstitution and thymic function through signal joint (sj) and beta T cell Receptor Excision Circles (TREC) quantification in a group of 33 haplo-HSCT pediatric patients and in a group of 24 unrelated CB-HSCT. Patients were transplanted mainly for hematological malignancies (n=46, including 31 Acute Lymphocytic Leukemia and 9 Acute Myeloid Leukemia). All children received a myeloablative conditioning regimen, including the combination of total body irradiation and chemotherapy (n=33) or chemotherapy alone (n=24). In haplo-HSCT, no pharmacological immune-suppression was given after the allograft, while patients given CB-HSCT received cyclosporine-A and steroids as Graft vs. Host Disease (GvHD) prophylaxis. In haplo-HSCT patients the median number of CD34+ cells infused/kg was 20.7 × 106 (range 8.7–41), while in patients given CB-HSCT the median number of nucleated cells infused/kg was 7.1) × 107 (range 1.4–12.5). The only significant difference between the 2 groups was that haplo-HSCT patients were older (p=.0008) than CB-HSCT patients (median age being 7.7 and 3.4 yrs, range 3–17 and 0.75–16 yrs, respectively). Patients treated for an hematological malignancy had a significant lower pre-transplant TREC value (p = .0002 and .004 for sj and beta TREC respectively) than those affected by non-malignant diseases in both groups. Number of sj and betaTREC per 150 000 PBMC or absolute counts per μl of blood, showed a very similar thymic function in both groups despite the older age of haplo-HSCT patients. TREC levels were comparable to those found before transplantation starting from 6 months after HSCT. Cumulative incidence of acute or chronic GvHD was low in both groups, with no significant impact on thymic function.In haplo-HSCT, but not in CB transplantation, patients treated for hematological malignancies (n=27) who relapsed (n=8) had a significantly lower level of thymic function (sjTREC) than those who did not relapse (n=19), before (p=0.03), after 3 (p=0.014) and 6 months (p=0.015) from the allograft. In this group of patients, relapse was not associated with age, conditioning regimen or number of CD34+ cells infused. In conclusion, we demonstrate the crucial importance of thymic function in the Graft-vs. Leukemia effect in the haplo-HSCT setting. Monitoring thymic function could be of predictive value in these patients. Disclosures:No relevant conflicts of interest to declare.

Direct and Natural Killer Cell-Mediated Antitumor Effects of Low-Dose Bortezomib in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) displays particular resistance to conventional cytostatic agents. Alternative treatment strategies focus on novel substances exhibiting antineoplastic and/or immunomodulatory activity enhancing for example natural killer (NK) cell antitumor reactivity. However, tumor-associated ligands engaging activating NK cell receptors are largely unknown. Exceptions are NKG2D ligands (NKG2DL) of the MHC class I-related chain and UL16-binding protein families, which potently stimulate NK cell responses. We studied the consequences of proteasome inhibition with regard to direct and NK cell-mediated effects against HCC. Primary human hepatocytes (PHH) from different donors, hepatoma cell lines, and NK cells were exposed to Bortezomib. Growth and viability of the different cells, and immunomodulatory effects including alterations of NKG2DL expression on hepatoma cells, specific induction of NK cell cytotoxicity and IFN-gamma production were investigated. Bortezomib treatment inhibited hepatoma cell growth with IC(50) values between 2.4 and 7.7 nmol/L. These low doses increased MICA/B mRNA levels, resulting in an increase of total and cell surface protein expression in hepatoma cells, thus stimulating cytotoxicity and IFN-gamma production of cocultured NK cells. Importantly, although NK cell IFN-gamma production was concentration-dependently reduced, low-dose Bortezomib neither induced NKG2DL expression or cell death in PHH nor altered NK cell cytotoxicity. Low-dose Bortezomib mediates a specific dual antitumor effect in HCC by inhibiting tumor cell proliferation and priming hepatoma cells for NK cell antitumor reactivity. Our data suggest that patients with HCC may benefit from Bortezomib treatment combined with immunotherapeutic approaches such as adoptive NK cell transfer taking advantage of enhanced NKG2D-mediated antitumor immunity.

Direct and Natural Killer Cell-Mediated Anti-Tumor Effects of Low-Dose Bortezomib in Hepatocellular Carcinoma.

Background & Aims: Hepatocellular carcinoma (HCC) displays a particular resistance to conventional cytostatic agents. Therefore, alternative treatment strategies focus on novel substances exhibiting anti-neoplastic and/or immunomodulatory activity enhancing for example Natural Killer (NK) cell anti-tumor reactivity. However, the tumor-associated ligands engaging activating NK cell receptors are largely unknown. Exceptions are the NKG2D ligands (NKG2DL) of the MIC and ULBP protein families, which potently stimulate NK cell responses. We studied the consequences of proteasome inhibition with regard to direct and NK cell-mediated effects against HCC.Methods: Primary human hepatocytes (PHH) from different donors, hepatoma cell lines and NK cells were exposed to Bortezomib. Growth and viability of hepatoma cells and PHH as well as immunomodulatory effects including alterations of NKG2DL expression on hepatoma cells, specific induction of NK cell cytotoxicity and IFN-γ production were investigated.Results: Bortezomib treatment inhibited hepatoma cell growth with IC50 values between 2.4 and 7.7 nanomol/liter. These low doses increased MICA/B mRNA levels and total and cell surface protein expression in hepatoma cells, which stimulated cytotoxicity and IFN-γ production of cocultured NK cells. Importantly, while IFN-γ production of NK cells was concentration-dependently reduced, low-dose Bortezomib neither induced NKG2DL expression or cell death in PHH nor altered NK cell cytotoxicity.Conclusions: Low-dose Bortezomib mediates a specific dual anti-tumor effect in HCC by inhibiting tumor cell proliferation and by priming hepatoma cells for NK cell anti-tumor reactivity. Our data suggest the clinical evaluation of Bortezomib treatment in HCC, especially in combination with immunotherapeutic approaches like adoptive NK cell transfer.