title: A high-throughput RNAi screen for detection of immune-checkpoint molecules that mediate tumor resistance to cytotoxic T lymphocytes.
abstract: The success of T cell-based cancer immunotherapy is limited by tumor's resistance against killing by cytotoxic T lymphocytes (CTLs). Tumor-immune resistance is mediated by cell surface ligands that engage immune-inhibitory receptors on T cells. These ligands represent potent targets for therapeutic inhibition. So far, only few immune-suppressive ligands have been identified. We here describe a rapid high-throughput siRNA-based screening approach that allows a comprehensive identification of ligands on human cancer cells that inhibit CTL-mediated tumor cell killing. We exemplarily demonstrate that CCR9, which is expressed in many cancers, exerts strong immune-regulatory effects on T cell responses in multiple tumors. Unlike PDL1, which inhibits TCR signaling, CCR9 regulates STAT signaling in T cells, resulting in reduced T-helper-1 cytokine secretion and reduced cytotoxic capacity. Moreover, inhibition of CCR9 expression on tumor cells facilitated immunotherapy of human tumors by tumor-specific T cells in vivo. Taken together, this method allows a rapid and comprehensive determination of immune-modulatory genes in human tumors which, as an entity, represent the 'immune modulatome' of cancer.
authors.affiliation: Division of Translational Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany n.khandelwal@dkfz.de p.beckhove@dkfz.de.
authors.forename: Nisit
authors.initials: N
authors.lastname: Khandelwal
authors.affiliation: Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany Department of Cell and Molecular Biology, Faculty of Medicine Mannheim, Heidelberg University, Heidelberg, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Breinig
authors.affiliation: Division of Translational Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Speck
authors.affiliation: Division of Translational Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Tillmann
authors.initials: T
authors.lastname: Michels
authors.affiliation: Division of Immunogenetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Kreutzer
authors.affiliation: Division of Translational Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sorrentino
authors.affiliation: Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Ashwini Kumar
authors.initials: AK
authors.lastname: Sharma
authors.affiliation: Division of Translational Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Ludmila
authors.initials: L
authors.lastname: Umansky
authors.affiliation: Division of Immunogenetics, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Heinke
authors.initials: H
authors.lastname: Conrad
authors.affiliation: Department of Molecular Oncology of Gastrointestinal Tumors, German Cancer Research Center (DKFZ) and Division of Pancreas Carcinoma Research, Surgery Clinic of Heidelberg University, Heidelberg, Germany.
authors.forename: Isabel
authors.initials: I
authors.lastname: Poschke
authors.affiliation: Department of Molecular Oncology of Gastrointestinal Tumors, German Cancer Research Center (DKFZ) and Division of Pancreas Carcinoma Research, Surgery Clinic of Heidelberg University, Heidelberg, Germany.
authors.forename: Rienk
authors.initials: R
authors.lastname: Offringa
authors.affiliation: Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC) Jena University Hospital, Jena, Germany Leibniz Institute for Natural Products Research and Infection Biology, Hans-Knöll-Institute, Jena, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: König
authors.affiliation: Department of Hematology/Oncology, Klinikum Darmstadt GmbH, Darmstadt, Germany.
authors.forename: Helga
authors.initials: H
authors.lastname: Bernhard
authors.affiliation: Sharett Institute of Oncology, Hadassah-Hebrew University Hospital, Jerusalem, Israel.
authors.forename: Arthur
authors.initials: A
authors.lastname: Machlenkin
authors.affiliation: Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ), Heidelberg, Germany Department of Cell and Molecular Biology, Faculty of Medicine Mannheim, Heidelberg University, Heidelberg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Boutros
authors.affiliation: Division of Translational Immunology, German Cancer Research Center (DKFZ), Heidelberg, Germany n.khandelwal@dkfz.de p.beckhove@dkfz.de.
authors.forename: Philipp
authors.initials: P
authors.lastname: Beckhove
mesh_terms: D000818:Animals; D060890:B7-H1 Antigen / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D007167:Immunotherapy / Q000379:methods*; D061986:MCF-7 Cells; D051379:Mice; D009374:Neoplasms, Experimental / Q000276:immunology / Q000473:pathology / Q000628:therapy; D034622:RNA Interference; D054388:Receptors, CCR / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology / Q000473:pathology
chemical_list: D060890:B7-H1 Antigen; C119309:CC chemokine receptor 9; C423236:CD274 protein, human; D054388:Receptors, CCR
keywords: RNAi screen; cancer immunotherapy; immune suppression