title: Signalling thresholds and negative B-cell selection in acute lymphoblastic leukaemia.
abstract: B cells are selected for an intermediate level of B-cell antigen receptor (BCR) signalling strength: attenuation below minimum (for example, non-functional BCR) or hyperactivation above maximum (for example, self-reactive BCR) thresholds of signalling strength causes negative selection. In ∼25% of cases, acute lymphoblastic leukaemia (ALL) cells carry the oncogenic BCR-ABL1 tyrosine kinase (Philadelphia chromosome positive), which mimics constitutively active pre-BCR signalling. Current therapeutic approaches are largely focused on the development of more potent tyrosine kinase inhibitors to suppress oncogenic signalling below a minimum threshold for survival. We tested the hypothesis that targeted hyperactivation--above a maximum threshold--will engage a deletional checkpoint for removal of self-reactive B cells and selectively kill ALL cells. Here we find, by testing various components of proximal pre-BCR signalling in mouse BCR-ABL1 cells, that an incremental increase of Syk tyrosine kinase activity was required and sufficient to induce cell death. Hyperactive Syk was functionally equivalent to acute activation of a self-reactive BCR on ALL cells. Despite oncogenic transformation, this basic mechanism of negative selection was still functional in ALL cells. Unlike normal pre-B cells, patient-derived ALL cells express the inhibitory receptors PECAM1, CD300A and LAIR1 at high levels. Genetic studies revealed that Pecam1, Cd300a and Lair1 are critical to calibrate oncogenic signalling strength through recruitment of the inhibitory phosphatases Ptpn6 (ref. 7) and Inpp5d (ref. 8). Using a novel small-molecule inhibitor of INPP5D (also known as SHIP1), we demonstrated that pharmacological hyperactivation of SYK and engagement of negative B-cell selection represents a promising new strategy to overcome drug resistance in human ALL.
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Zhengshan
authors: Z
authors: Chen
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Seyedmehdi
authors: S
authors: Shojaee
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Maike
authors: M
authors: Buchner
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Huimin
authors: H
authors: Geng
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Jae Woong
authors: JW
authors: Lee
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Lars
authors: L
authors: Klemm
authors: Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095, USA.
authors: Björn
authors: B
authors: Titz
authors: Crump Institute for Molecular Imaging, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California 90095, USA.
authors: Thomas G
authors: TG
authors: Graeber
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Eugene
authors: E
authors: Park
authors: Rosalind Russell-Ephraim P. Engleman Medical Research Center for Arthritis, Division of Rheumatology, Department of Medicine, Howard Hughes Medical Institute, University of California, San Francisco, California 94143, USA.
authors: Ying Xim
authors: YX
authors: Tan
authors: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors: Anne
authors: A
authors: Satterthwaite
authors: Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10466, USA.
authors: Elisabeth
authors: E
authors: Paietta
authors: Division of Pediatric Oncology and Center for Childhood Cancer Research, Children's Hospital of Philadelphia, Philadelphia, Philadelphia 19104, USA.
authors: Stephen P
authors: SP
authors: Hunger
authors: University of New Mexico Cancer Center, Albuquerque, New Mexico 87102, USA.
authors: Cheryl L
authors: CL
authors: Willman
authors: Departments of Medicine and Pharmacology, Weill Cornell Medical College, New York, New York 10065, USA.
authors: Ari
authors: A
authors: Melnick
authors: Pediatric Hematology-Oncology, University of California, San Francisco, California 94143, USA.
authors: Mignon L
authors: ML
authors: Loh
authors: Department of Molecular Microbiology and Immunology, University of Southern California, Los Angeles, California 90033, USA.
authors: Jae U
authors: JU
authors: Jung
authors: Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA.
authors: John E
authors: JE
authors: Coligan
authors: Autoimmunity and Functional Genomics Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA.
authors: Silvia
authors: S
authors: Bolland
authors: The Campbell Family Institute for Breast Cancer Research, University Health Network, 620 University Avenue, Toronto, Ontario M5G 2M9, Canada.
authors: Tak W
authors: TW
authors: Mak
authors: Department of Anatomy, University of California, San Francisco, California 94143, USA.
authors: Andre
authors: A
authors: Limnander
authors: Institute of Immunology, University Clinics Ulm, 89081 Ulm, Germany.
authors: Hassan
authors: H
authors: Jumaa
authors: BIOSS Centre for Biological Signalling Studies and Faculty of Biology, Albert-Ludwigs-Universität Freiburg, and MPI of Immunbiologie and Epigenetics, 79104 Freiburg, Germany.
authors: Michael
authors: M
authors: Reth
authors: Rosalind Russell-Ephraim P. Engleman Medical Research Center for Arthritis, Division of Rheumatology, Department of Medicine, Howard Hughes Medical Institute, University of California, San Francisco, California 94143, USA.
authors: Arthur
authors: A
authors: Weiss
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Clifford A
authors: CA
authors: Lowell
authors: Department of Laboratory Medicine, University of California, San Francisco, California 94143, USA.
authors: Markus
authors: M
authors: Müschen
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D002471:Cell Transformation, Neoplastic; D004195:Disease Models, Animal; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D017353:Gene Deletion; D006801:Humans; D000072181:Inositol Polyphosphate 5-Phosphatases; D047908:Intracellular Signaling Peptides and Proteins / Q000819:agonists / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D054448:Precursor Cells, B-Lymphoid / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011947:Receptors, Antigen, B-Cell / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D000072377:Syk Kinase; D014443:Tyrosine / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D015703:Antigens, CD; C515070:CD300A protein, human; D047908:Intracellular Signaling Peptides and Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011947:Receptors, Antigen, B-Cell; D011971:Receptors, Immunologic; C108073:leukocyte-associated immunoglobulin-like receptor 1; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D010744:Phosphoric Monoester Hydrolases; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C509248:Ptpn6 protein, mouse; D000072181:Inositol Polyphosphate 5-Phosphatases; C000606430:INPP5D protein, human; C000606433:Inpp5d protein, mouse; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases