title: In vivo adhesion of malignant B cells to bone marrow microvasculature is regulated by α4β1 cytoplasmic-binding proteins.
abstract: Multiple myeloma (MM) and chronic lymphocytic leukemia (CLL) cells must attach to the bone marrow (BM) microvasculature before lodging in the BM microenvironment. Using intravital microscopy (IVM) of the BM calvariae we demonstrate that the α4β1 integrin is required for MM and CLL cell firm arrest onto the BM microvasculature, while endothelial P-selectin and E-selectin mediate cell rolling. Talin, kindlin-3 and ICAP-1 are β1-integrin-binding partners that regulate β1-mediated cell adhesion. We show that talin and kindlin-3 cooperatively stimulate high affinity and strength of α4β1-dependent MM and CLL cell attachment, whereas ICAP-1 negatively regulates this adhesion. A functional connection between talin/kindlin-3 and Rac1 was found to be required for MM cell attachment mediated by α4β1. Importantly, IVM analyses with talin- and kindlin-3-silenced MM cells indicate that these proteins are needed for cell arrest on the BM microvasculature. Instead, MM cell arrest is repressed by ICAP-1. Moreover, MM cells silenced for talin and kindlin-3, and cultured on α4β1 ligands showed higher susceptibility to bortezomib-mediated cell apoptosis. Our results highlight the requirement of α4β1 and selectins for the in vivo attachment of MM and CLL cells to the BM microvasculature, and indicate that talin, kindlin-3 and ICAP-1 differentially control physiological adhesion by regulating α4β1 activity.
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Martínez-Moreno
authors.affiliation: Area of Cell and Developmental Biology, Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Leiva
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Aguilera-Montilla
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Sevilla-Movilla
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Isern de Val
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Arellano-Sánchez
authors.affiliation: Department of Hematology, Hospital Universitario de Salamanca, Salamanca, Spain.
authors.forename: N C
authors.initials: NC
authors.lastname: Gutiérrez
authors.affiliation: Section of Hematology, Hospital Universitario 12 de Octubre, Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Maldonado
authors.affiliation: Section of Hematology, Hospital Universitario 12 de Octubre, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Martínez-López
authors.affiliation: Section of Hematology, Hospital General Universitario Gregorio Marañón, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Buño
authors.affiliation: Hematology Unit, Hospital Universitario Puerta de Hierro, Madrid, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: García-Marco
authors.affiliation: Section of Immuno-Oncology, Hospital General Universitario Gregorio Marañón, Complutense University School of Medicine, Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Sánchez-Mateos
authors.affiliation: Area of Cell and Developmental Biology, Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain.|Institute for Cardiovascular Prevention, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: A
authors.identifier: http://orcid.org/0000-0001-5513-555X
authors.initials: A
authors.lastname: Hidalgo
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: García-Pardo
authors.affiliation: Department of Cellular and Molecular Medicine, Centro de Investigaciones Biológicas (CSIC), Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Teixidó
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D001853:Bone Marrow / Q000378:metabolism / Q000473:pathology*; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D003593:Cytoplasm / Q000378:metabolism; D019040:E-Selectin / Q000235:genetics / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology*; D005434:Flow Cytometry; D006801:Humans; D039041:Integrin alpha4beta1 / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D000069416:Intravital Microscopy; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D055806:Microvessels; D009101:Multiple Myeloma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism; D019007:P-Selectin / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016608:Talin / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019040:E-Selectin; C477322:FERMT3 protein, human; C108257:ITGB1BP1 protein, human; D039041:Integrin alpha4beta1; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D019007:P-Selectin; D012333:RNA, Messenger; C546936:SELE protein, human; C546937:SELP protein, human; C518832:TLN1 protein, human; D016608:Talin