Histone deacetylase inhibitors enhance expression of NKG2D ligands in Ewing sarcoma and sensitize for natural killer cell-mediated cytolysis

Berghuis Dagmar, Schilham, Vos, Santos, Kloess Stephan, Buddingh', Egeler, Hogendoorn, Lankester

Description

Ewing sarcoma patients have a poor prognosis despite multimodal therapy. Integration of combination immunotherapeutic strategies into first-/second-line regimens represents promising treatment options, particularly for patients with intrinsic or acquired resistance to conventional therapies. We evaluated the susceptibility of Ewing sarcoma to natural killer cell-based combination immunotherapy, by assessing the capacity of histone deacetylase inhibitors to improve immune recognition and sensitize for natural killer cell cytotoxicity. Methods Using flow cytometry, ELISA and immunohistochemistry, expression of natural killer cell receptor ligands was assessed in chemotherapy-sensitive/-resistant Ewing sarcoma cell lines, plasma and tumours. Natural killer cell cytotoxicity was evaluated in Chromium release assays. Using ATM/ATR inhibitor caffeine, the contribution of the DNA damage response pathway to histone deacetylase inhibitor-induced ligand expression was assessed. Results Despite comparable expression of natural killer cell receptor ligands, chemotherapy-resistant Ewing sarcoma exhibited reduced susceptibility to resting natural killer cells. Interleukin-15-activation of natural killer cells overcame this reduced sensitivity. Histone deacetylase inhibitor-pretreatment induced NKG2D-ligand expression in an ATM/ATR-dependent manner and sensitized for NKG2D-dependent cytotoxicity (2/4 cell lines). NKG2D-ligands were expressed in vivo , regardless of chemotherapy-response and disease stage. Soluble NKG2D-ligand plasma concentrations did not differ between patients and controls. Conclusion Our data provide a rationale for combination immunotherapy involving immune effector and target cell manipulation in first-/second-line treatment regimens for Ewing sarcoma.

Sujets

• Ewing's sarcoma
• Natural killer cell
• Histone deacetylase inhibitor

Informations

• Publié par: biomed
• Publié le: 01 janvier 2012
• Nombre de lectures: 7
• Langue: English

Extrait

Berghuiset al.Clinical Sarcoma Research2012,2:8 http://www.clinicalsarcomaresearch.com/content/2/1/8

R E S E A R C H

CLINICAL SARCOMA RESEARCH

Open Access

Histone deacetylase inhibitors enhance expression of NKG2D ligands in Ewing sarcoma and sensitize for natural killer cellmediated cytolysis 1,2 2 2 2 3 2 Dagmar Berghuis , Marco W Schilham , Hanneke I Vos , Susy J Santos , Stephan Kloess , Emilie P Buddingh’, 2 1 2* R Maarten Egeler , Pancras CW Hogendoorn and Arjan C Lankester

Abstract Background:Ewing sarcoma patients have a poor prognosis despite multimodal therapy. Integration of combination immunotherapeutic strategies into first/secondline regimens represents promising treatment options, particularly for patients with intrinsic or acquired resistance to conventional therapies. We evaluated the susceptibility of Ewing sarcoma to natural killer cellbased combination immunotherapy, by assessing the capacity of histone deacetylase inhibitors to improve immune recognition and sensitize for natural killer cell cytotoxicity. Methods:Using flow cytometry, ELISA and immunohistochemistry, expression of natural killer cell receptor ligands was assessed in chemotherapysensitive/resistant Ewing sarcoma cell lines, plasma and tumours. Natural killer cell cytotoxicity was evaluated in Chromium release assays. Using ATM/ATR inhibitor caffeine, the contribution of the DNA damage response pathway to histone deacetylase inhibitorinduced ligand expression was assessed. Results:Despite comparable expression of natural killer cell receptor ligands, chemotherapyresistant Ewing sarcoma exhibited reduced susceptibility to resting natural killer cells. Interleukin15activation of natural killer cells overcame this reduced sensitivity. Histone deacetylase inhibitorpretreatment induced NKG2Dligand expression in an ATM/ATRdependent manner and sensitized for NKG2Ddependent cytotoxicity (2/4 cell lines). NKG2Dligands were expressedin vivo, regardless of chemotherapyresponse and disease stage. Soluble NKG2Dligand plasma concentrations did not differ between patients and controls. Conclusion:Our data provide a rationale for combination immunotherapy involving immune effector and target cell manipulation in first/secondline treatment regimens for Ewing sarcoma. Keywords:Ewing sarcoma, natural killer cells, histone deacetylase inhibitor, combination immunotherapy, che motherapyresistance, tumour immunology

Introduction Ewing sarcoma is an aggressive round cell sarcoma characterized by specific gene fusions most commonly involvingTETgene family products, though rarely other activating transcription factors [13]. It usually affects bone or soft tissue in children and young adults. Despite multimodal therapy consisting of highdose

* Correspondence: [e-mail] 2 Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands Full list of author information is available at the end of the article

chemotherapy, surgery and radiotherapy, survival of patients with Ewing sarcoma has not improved signifi cantly during the past decade. Patients with therapy resistant or metastatic Ewing sarcoma have the most unfavorable prognosis, with a 5year overall survival of less than 30% [46], which has recently been demon strated to be independent of Ewing sarcomaETS fusion type [4,5]. Natural killer (NK) cells are the main cytotoxic effec tor cells of the innate immune system, contributing to host antimicrobial and antitumour immune responses.

© 2012 Berghuis et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.