title: The WHIM-like CXCR4(S338X) somatic mutation activates AKT and ERK, and promotes resistance to ibrutinib and other agents used in the treatment of Waldenstrom's Macroglobulinemia.
abstract: CXCR4(WHIM) somatic mutations are common Waldenstrom's Macroglobulinemia (WM), and are associated with clinical resistance to ibrutinib. We engineered WM cells to express the most common WHIM (Warts, Hypogammaglobulinemia, Infections and Myelokathexis), CXCR(S338X) mutation in WM. Following SDF-1a stimulation, CXCR4(S338X) WM cells exhibited decreased receptor internalization, enhanced and sustained AKT kinase (AKT) and extracellular regulated kinase (ERK) signaling, decreased poly (ADP-ribose) polymerase and caspase 3 cleavage, and decreased Annexin V staining versus CXCR4 wild-type (WT) cells. CXCR4(S338X)-related signaling and survival effects were blocked by the CXCR4 inhibitor AMD3100. SDF-1a-treated CXCR4(S338X) WM cells showed sustained AKT and ERK activation and decreased apoptotic changes versus CXCR4(WT) cells following ibrutinib treatment, findings which were also reversed by AMD3100. AKT or ERK antagonists restored ibrutinib-triggered apoptotic changes in SDF-1a-treated CXCR4(S338X) WM cells demonstrating their role in SDF-1a-mediated ibrutinib resistance. Enhanced bone marrow pAKT staining was also evident in CXCR4(WHIM) versus CXCR4(WT) WM patients, and remained active despite ibrutinib therapy in CXCR4(WHIM) patients. Last, CXCR4(S338X) WM cells showed varying levels of resistance to other WM relevant therapeutics, including bendamustine, fludarabine, bortezomib and idelalisib in the presence of SDF-1a. These studies demonstrate a functional role for CXCR4(WHIM) mutations, and provide a framework for investigation of CXCR4 inhibitors in WM.
authors.affiliation: 1] Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Cao
authors.affiliation: 1] Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA [2] Department of Pathology, Boston University Medical School, Boston, MA, USA.
authors.forename: Z R
authors.initials: ZR
authors.lastname: Hunter
authors.affiliation: 1] Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Xu
authors.affiliation: 1] Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: G
authors.initials: G
authors.lastname: Yang
authors.affiliation: Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.affiliation: Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Patterson
authors.affiliation: Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA.
authors.forename: N
authors.initials: N
authors.lastname: Tsakmaklis
authors.affiliation: Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Kanan
authors.affiliation: 1] Department of Medicine, Harvard Medical School, Boston, MA, USA [2] Department of Pathology, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: S
authors.initials: S
authors.lastname: Rodig
authors.affiliation: 1] Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Castillo
authors.affiliation: 1] Bing Center for Waldenstrom's Macroglobulinemia, Dana Farber Cancer Institute, Boston, MA, USA [2] Department of Medicine, Harvard Medical School, Boston, MA, USA.
authors.forename: S P
authors.initials: SP
authors.lastname: Treon
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D010880:Piperidines; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011720:Pyrazoles / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D019718:Receptors, CXCR4 / Q000235:genetics*; D008258:Waldenstrom Macroglobulinemia / Q000188:drug therapy* / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; C527276:CXCR4 protein, human; D010880:Piperidines; D011720:Pyrazoles; D011743:Pyrimidines; D019718:Receptors, CXCR4; C551803:ibrutinib; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D000225:Adenine