1
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Discovery of a Benzimidazole-based Dual FLT3/TrKA Inhibitor Targeting Acute Myeloid Leukemia. Bioorg Med Chem 2021; 56:116596. [DOI: 10.1016/j.bmc.2021.116596] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/13/2021] [Accepted: 12/27/2021] [Indexed: 12/17/2022]
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2
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CBL mutations drive PI3K/AKT signaling via increased interaction with LYN and PIK3R1. Blood 2021; 137:2209-2220. [PMID: 33512474 DOI: 10.1182/blood.2020006528] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 12/14/2020] [Indexed: 12/13/2022] Open
Abstract
Casitas B-lineage lymphoma (CBL) encodes an E3 ubiquitin ligase and signaling adaptor that regulates receptor and nonreceptor tyrosine kinases. Recurrent CBL mutations occur in myeloid neoplasms, including 10% to 20% of chronic myelomonocytic leukemia (CMML) cases, and selectively disrupt the protein's E3 ubiquitin ligase activity. CBL mutations have been associated with poor prognosis, but the oncogenic mechanisms and therapeutic implications of CBL mutations remain incompletely understood. We combined functional assays and global mass spectrometry to define the phosphoproteome, CBL interactome, and mechanism of signaling activation in a panel of cell lines expressing an allelic series of CBL mutations. Our analyses revealed that increased LYN activation and interaction with mutant CBL are key drivers of enhanced CBL phosphorylation, phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) recruitment, and downstream phosphatidylinositol 3-kinase (PI3K)/AKT signaling in CBL-mutant cells. Signaling adaptor domains of CBL, including the tyrosine kinase-binding domain, proline-rich region, and C-terminal phosphotyrosine sites, were all required for the oncogenic function of CBL mutants. Genetic ablation or dasatinib-mediated inhibition of LYN reduced CBL phosphorylation, CBL-PIK3R1 interaction, and PI3K/AKT signaling. Furthermore, we demonstrated in vitro and in vivo antiproliferative efficacy of dasatinib in CBL-mutant cell lines and primary CMML. Overall, these mechanistic insights into the molecular function of CBL mutations provide rationale to explore the therapeutic potential of LYN inhibition in CBL-mutant myeloid malignancies.
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3
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Yu M, Fang ZX, Wang WW, Zhang Y, Bu ZL, Liu M, Xiao XH, Zhang ZL, Zhang XM, Cao Y, Wang YY, Lei H, Xu HZ, Wu YZ, Liu W, Wu YL. Wu-5, a novel USP10 inhibitor, enhances crenolanib-induced FLT3-ITD-positive AML cell death via inhibiting FLT3 and AMPK pathways. Acta Pharmacol Sin 2021; 42:604-612. [PMID: 32694757 DOI: 10.1038/s41401-020-0455-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 06/02/2020] [Indexed: 02/07/2023] Open
Abstract
The kinase FLT3 internal tandem duplication (FLT3-ITD) is related to poor clinical outcomes of acute myeloid leukemia (AML). FLT3 inhibitors have provided novel strategies for the treatment of FLT3-ITD-positive AML. But they are limited by rapid development of acquired resistance and refractory in monotherapy. Recent evidence shows that inducing the degradation of FLT3-mutated protein is an attractive strategy for the treatment of FLT3-ITD-positive AML, especially those with FLT3 inhibitor resistance. In this study we identified Wu-5 as a novel USP10 inhibitor inducing the degradation of FLT3-mutated protein. We showed that Wu-5 selectively inhibited the viability of FLT3 inhibitor-sensitive (MV4-11, Molm13) and -resistant (MV4-11R) FLT3-ITD-positive AML cells with IC50 of 3.794, 5.056, and 8.386 μM, respectively. Wu-5 (1-10 μM) dose-dependently induced apoptosis of MV4-11, Molm13, and MV4-11R cells through the proteasome-mediated degradation of FLT3-ITD. We further demonstrated that Wu-5 directly interacted with and inactivated USP10, the deubiquitinase for FLT3-ITD in vitro (IC50 value = 8.3 µM) and in FLT3-ITD-positive AML cells. Overexpression of USP10 abrogated Wu-5-induced FLT3-ITD degradation and cell death. Also, the combined treatment of Wu-5 and crenolanib produced synergistic cell death in FLT3-ITD-positive cells via the reduction of both FLT3 and AMPKα proteins. In support of this, AMPKα inhibitor compound C synergistically enhanced the anti-leukemia effect of crenolanib, while AMPKα activator metformin inhibited the anti-leukemia effect of crenolanib. In summary, we demonstrate that Wu-5, a novel USP10 inhibitor, can overcome FLT3 inhibitor resistance and synergistically enhance the anti-AML effect of crenolanib through targeting FLT3 and AMPKα pathway.
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4
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Abstract
In recent years CMML has received increased attention as the most commonly observed MDS/MPN overlap syndrome. Renewed interest has occurred in part due to widespread adoption of next-generation sequencing panels that help render the diagnosis in the absence of morphologic dysplasia. Although most CMML patients exhibit somatic mutations in epigenetic modifiers, spliceosome components, transcription factors and signal transduction genes, it is increasingly clear that a small subset harbors an inherited predisposition to CMML and other myeloid neoplasms. More intriguing is the fact that the mutational spectrum observed in CMML is found in other types of myeloid leukemias, begging the question of how similar genetic backgrounds can lead to such divergent clinical phenotypes. In this review we present a contemporary snapshot of the genetic complexity inherent to CMML, explore the relationship between genotype-phenotype and present a stepwise model of CMML pathogenesis and progression.
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Affiliation(s)
- Ami B Patel
- Division of Hematology and Hematologic Malignancies, University of Utah, Salt Lake City, UT, USA.,Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Michael W Deininger
- Division of Hematology and Hematologic Malignancies, University of Utah, Salt Lake City, UT, USA.,Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
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5
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Ali AM, Cooper J, Walker A, Jones D, Saad A. Adult-onset acute myeloid leukaemia in a patient with germline mutation of CBL. Br J Haematol 2020; 192:665-667. [PMID: 33216958 DOI: 10.1111/bjh.17234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/18/2020] [Accepted: 10/20/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Alaa M Ali
- Department of Internal Medicine, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - Julia Cooper
- Department of Internal Medicine, Division of Human Genetics, The Ohio State University, Columbus, OH, USA
| | - Alison Walker
- Department of Internal Medicine, Division of Hematology, The Ohio State University, Columbus, OH, USA
| | - Daniel Jones
- Department of Pathology, Division of Molecular Pathology, The Ohio State University, Columbus, OH, USA
| | - Ayman Saad
- Department of Internal Medicine, Division of Hematology, The Ohio State University, Columbus, OH, USA
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6
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Watanabe J, Sato K, Osawa Y, Horiuchi T, Kato S, Hikota-Saga R, Maekawa T, Yamamura T, Kobayashi A, Kobayashi S, Kimura F. CBL mutation and MEFV single-nucleotide variant are important genetic predictors of tumor reduction in glucocorticoid-treated patients with chronic myelomonocytic leukemia. Int J Hematol 2018; 108:47-57. [PMID: 29600428 DOI: 10.1007/s12185-018-2436-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 03/17/2018] [Accepted: 03/19/2018] [Indexed: 11/28/2022]
Abstract
Glucocorticoid (GC) therapy occasionally relieves tumor-related fever and promotes tumor reduction in patients with chronic myelomonocytic leukemia (CMML). A mutation analysis of 24 patients with CMML revealed the relationship of GC effectiveness, defined as a monocyte reduction of > 50% within 3 days of methylprednisolone administration, with the MEFV single-nucleotide variant (SNV) and CBL mutation. Lipopolysaccharide-stimulated monocytes harboring MEFV E148Q produced greater amounts of IL-1β and TNF-α than did wild-type monocytes; this was effectively suppressed by GC. Primary CMML cells harboring the MEFV SNV and CBL mutation, and the myelomonocytic leukemia cell line GDM-1, harboring the CBL mutation, were both more significantly suppressed than non-mutated cells following GC treatment in the presence of GM-CSF. A loss-of-function CBL mutation prolonged STAT5 phosphorylation after GM-CSF stimulation, which was rapidly terminated in both patient samples and GDM-1 cells. In conclusion, GC therapy effectively treats CMML cells harboring the MEFV SNV and CBL mutation by reducing inflammatory cytokine production and terminating prolonged STAT5 phosphorylation in the GM-CSF signaling pathway.
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Affiliation(s)
- Junichi Watanabe
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Ken Sato
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Yukiko Osawa
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Toshikatsu Horiuchi
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Shoichiro Kato
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Reina Hikota-Saga
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Takaaki Maekawa
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Takeshi Yamamura
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Ayako Kobayashi
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Shinichi Kobayashi
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan
| | - Fumihiko Kimura
- Division of Hematology, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama, 359-8513, Japan.
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7
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Da Silva L, Fonseca-Alves CE, Thompson JJ, Foster RA, Wood GA, Amorim RL, Coomber BL. Pilot assessment of vascular endothelial growth factor receptors and trafficking pathways in recurrent and metastatic canine subcutaneous mast cell tumours. Vet Med Sci 2017; 3:146-155. [PMID: 29067211 PMCID: PMC5645839 DOI: 10.1002/vms3.66] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Canine subcutaneous mast cell tumour (scMCT) shows less aggressive biological behaviour than cutaneous MCT. Vascular endothelial growth factor receptor 2 (VEGFR2) is expressed by neoplastic cells in canine scMCT, but the relevance of this signalling pathway for disease pathobiology is not clear. The objective of this study was to quantify VEGF‐A, VEGFR2, pVEGFR2, the VEGF co‐receptor Neuropilin 1 (NRP‐1) and the E3 ubiquitin protein ligase c‐Cbl in canine scMCT, and to evaluate their association with disease outcome. Immunohistochemical staining for biomarkers was quantified from 14 cases of canine scMCT using manual and computer‐assisted methods. Kaplan–Meier curves were generated for disease‐free survival (DFS) and compared using Mantel–Cox log‐rank analysis. Cases with high levels of neoplastic cell VEGFR2, pVEGFR2 or c‐CBL immunoreactivity had significantly reduced DFS. All cases displayed neoplastic cells positive for VEGF‐A, which was significantly associated with pVEGFR2 immunoreactivity. There were also significant positive correlations between VEGFR2 and pVEGFR2, and between c‐CBL and pVEGFR2 levels. This pilot study demonstrates the potential utility of these markers in a subset of scMCT in dogs.
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Affiliation(s)
- Lucas Da Silva
- Department of Biomedical SciencesUniversity of GuelphGuelphOntarioCanada
| | - Carlos E Fonseca-Alves
- Department of Veterinary ClinicUniversity of São Paulo State -UNESPBotucatuSão PauloBrazil
| | - Jennifer J Thompson
- Department of PathobiologyOntario Veterinary CollegeUniversity of GuelphGuelphOntarioCanada
| | - Robert A Foster
- Department of PathobiologyOntario Veterinary CollegeUniversity of GuelphGuelphOntarioCanada
| | - Geoffrey A Wood
- Department of PathobiologyOntario Veterinary CollegeUniversity of GuelphGuelphOntarioCanada
| | - Renee L Amorim
- Department of Veterinary ClinicUniversity of São Paulo State -UNESPBotucatuSão PauloBrazil
| | - Brenda L Coomber
- Department of Biomedical SciencesUniversity of GuelphGuelphOntarioCanada
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8
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Nadeau SA, An W, Mohapatra BC, Mushtaq I, Bielecki TA, Luan H, Zutshi N, Ahmad G, Storck MD, Sanada M, Ogawa S, Band V, Band H. Structural Determinants of the Gain-of-Function Phenotype of Human Leukemia-associated Mutant CBL Oncogene. J Biol Chem 2017; 292:3666-3682. [PMID: 28082680 DOI: 10.1074/jbc.m116.772723] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Indexed: 01/19/2023] Open
Abstract
Mutations of the tyrosine kinase-directed ubiquitin ligase CBL cause myeloid leukemias, but the molecular determinants of the dominant leukemogenic activity of mutant CBL oncogenes are unclear. Here, we first define a gain-of-function attribute of the most common leukemia-associated CBL mutant, Y371H, by demonstrating its ability to increase proliferation of hematopoietic stem/progenitor cells (HSPCs) derived from CBL-null and CBL/CBL-B-null mice. Next, we express second-site point/deletion mutants of CBL-Y371H in CBL/CBL-B-null HSPCs or the cytokine-dependent human leukemic cell line TF-1 to show that individual or combined Tyr → Phe mutations of established phosphotyrosine residues (Tyr-700, Tyr-731, and Tyr-774) had little impact on the activity of the CBL-Y371H mutant in HSPCs, and the triple Tyr → Phe mutant was only modestly impaired in TF-1 cells. In contrast, intact tyrosine kinase-binding (TKB) domain and proline-rich region (PRR) were critical in both cell models. PRR deletion reduced the stem cell factor (SCF)-induced hyper-phosphorylation of the CBL-Y371H mutant and the c-KIT receptor and eliminated the sustained p-ERK1/2 and p-AKT induction by SCF. GST fusion protein pulldowns followed by phospho-specific antibody array analysis identified distinct CBL TKB domains or PRR-binding proteins that are phosphorylated in CBL-Y371H-expressing TF-1 cells. Our results support a model of mutant CBL gain-of-function in which mutant CBL proteins effectively compete with the remaining wild type CBL-B and juxtapose TKB domain-associated PTKs with PRR-associated signaling proteins to hyper-activate signaling downstream of hematopoietic growth factor receptors. Elucidation of mutant CBL domains required for leukemogenesis should facilitate targeted therapy approaches for patients with mutant CBL-driven leukemias.
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Affiliation(s)
- Scott A Nadeau
- From the Eppley Institute for Research in Cancer and Allied Diseases.,the Departments of Genetics, Cell Biology and Anatomy
| | - Wei An
- From the Eppley Institute for Research in Cancer and Allied Diseases.,the Departments of Genetics, Cell Biology and Anatomy
| | - Bhopal C Mohapatra
- From the Eppley Institute for Research in Cancer and Allied Diseases.,Biochemistry and Molecular Biology
| | - Insha Mushtaq
- From the Eppley Institute for Research in Cancer and Allied Diseases.,Pathology and Microbiology, College of Medicine, and
| | | | - Haitao Luan
- From the Eppley Institute for Research in Cancer and Allied Diseases.,the Departments of Genetics, Cell Biology and Anatomy
| | - Neha Zutshi
- From the Eppley Institute for Research in Cancer and Allied Diseases.,Pathology and Microbiology, College of Medicine, and
| | - Gulzar Ahmad
- From the Eppley Institute for Research in Cancer and Allied Diseases
| | - Matthew D Storck
- From the Eppley Institute for Research in Cancer and Allied Diseases
| | - Masashi Sanada
- the Department of Pathology and Tumor Biology, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Seishi Ogawa
- the Department of Pathology and Tumor Biology, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Vimla Band
- From the Eppley Institute for Research in Cancer and Allied Diseases.,the Departments of Genetics, Cell Biology and Anatomy.,the Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
| | - Hamid Band
- From the Eppley Institute for Research in Cancer and Allied Diseases, .,the Departments of Genetics, Cell Biology and Anatomy.,Biochemistry and Molecular Biology.,Pathology and Microbiology, College of Medicine, and.,the Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and
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9
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Abstract
CNS germ cell tumors (GCT) are rare tumors that arise in midline brain regions (mostly pineal or suprasellar). They are of two types, germinoma and nongerminomatous GCT (NGGCT) which include teratoma, choriocarcinoma, yolk sac, embyronal carcinoma and mixed GCT. Tissue is needed for diagnosis unless serum or cerebrospinal fluid markers, b-HCG or AFP, are elevated. Germinomas can be cured with radiation therapy (RT) alone (whole ventricle fields, if localized), but chemotherapy may permit RT dose-reduction. Best outcomes for NGGCT are with RT and chemotherapy. Craniospinal RT is needed for all disseminated tumors and best survival for localized NGGCT has included craniospinal RT. Recent genetic findings in CNS GCT may lead to therapies targeting their oncogenic pathways.
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Affiliation(s)
- Patricia L Robertson
- Departments of Pediatrics & Neurology, University of Michigan Medical School, Pediatric Neuro-Oncology, 12-718 C.S. Mott Children’s Hospital, 1540 E. Hospital Dr., Ann Arbor, MI 48109, USA
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10
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Goyama S, Schibler J, Gasilina A, Shrestha M, Lin S, Link KA, Chen J, Whitman SP, Bloomfield CD, Nicolet D, Assi SA, Ptasinska A, Heidenreich O, Bonifer C, Kitamura T, Nassar NN, Mulloy JC. UBASH3B/Sts-1-CBL axis regulates myeloid proliferation in human preleukemia induced by AML1-ETO. Leukemia 2015; 30:728-39. [PMID: 26449661 DOI: 10.1038/leu.2015.275] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 09/22/2015] [Accepted: 09/30/2015] [Indexed: 12/24/2022]
Abstract
The t(8;21) rearrangement, which creates the AML1-ETO fusion protein, represents the most common chromosomal translocation in acute myeloid leukemia (AML). Clinical data suggest that CBL mutations are a frequent event in t(8;21) AML, but the role of CBL in AML1-ETO-induced leukemia has not been investigated. In this study, we demonstrate that CBL mutations collaborate with AML1-ETO to expand human CD34+ cells both in vitro and in a xenograft model. CBL depletion by shRNA also promotes the growth of AML1-ETO cells, demonstrating the inhibitory function of endogenous CBL in t(8;21) AML. Mechanistically, loss of CBL function confers hyper-responsiveness to thrombopoietin and enhances STAT5/AKT/ERK/Src signaling in AML1-ETO cells. Interestingly, we found the protein tyrosine phosphatase UBASH3B/Sts-1, which is known to inhibit CBL function, is upregulated by AML1-ETO through transcriptional and miR-9-mediated regulation. UBASH3B/Sts-1 depletion induces an aberrant pattern of CBL phosphorylation and impairs proliferation in AML1-ETO cells. The growth inhibition caused by UBASH3B/Sts-1 depletion can be rescued by ectopic expression of CBL mutants, suggesting that UBASH3B/Sts-1 supports the growth of AML1-ETO cells partly through modulation of CBL function. Our study reveals a role of CBL in restricting myeloid proliferation of human AML1-ETO-induced leukemia, and identifies UBASH3B/Sts-1 as a potential target for pharmaceutical intervention.
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Affiliation(s)
- S Goyama
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA.,Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - J Schibler
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - A Gasilina
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - M Shrestha
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - S Lin
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - K A Link
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - J Chen
- Section of Hematology/Oncology, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - S P Whitman
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - C D Bloomfield
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - D Nicolet
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA.,Alliance for Clinical Trials in Oncology Statistics and Data Center, Mayo Clinic, Rochester, MN, USA
| | - S A Assi
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - A Ptasinska
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - O Heidenreich
- Northern Institute for Cancer Research, Newcastle University, Newcastle upon Tyne, UK
| | - C Bonifer
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - T Kitamura
- Division of Cellular Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - N N Nassar
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - J C Mulloy
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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11
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Huang D, Nagata Y, Grossmann V, Radivoyevitch T, Okuno Y, Nagae G, Hosono N, Schnittger S, Sanada M, Przychodzen B, Kon A, Polprasert C, Shen W, Clemente MJ, Phillips JG, Alpermann T, Yoshida K, Nadarajah N, Sekeres MA, Oakley K, Nguyen N, Shiraishi Y, Shiozawa Y, Chiba K, Tanaka H, Koeffler HP, Klein HU, Dugas M, Aburatani H, Miyano S, Haferlach C, Kern W, Haferlach T, Du Y, Ogawa S, Makishima H. BRCC3 mutations in myeloid neoplasms. Haematologica 2015; 100:1051-7. [PMID: 26001790 DOI: 10.3324/haematol.2014.111989] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 05/12/2015] [Indexed: 01/10/2023] Open
Abstract
Next generation sequencing technologies have provided insights into the molecular heterogeneity of various myeloid neoplasms, revealing previously unknown somatic genetic events. In our cohort of 1444 cases analyzed by next generation sequencing, somatic mutations in the gene BRCA1-BRCA2-containing complex 3 (BRCC3) were identified in 28 cases (1.9%). BRCC3 is a member of the JAMM/MPN+ family of zinc metalloproteases capable of cleaving Lys-63 linked polyubiquitin chains, and is implicated in DNA repair. The mutations were located throughout its coding region. The average variant allelic frequency of BRCC3 mutations was 30.1%, and by a serial sample analysis at two different time points a BRCC3 mutation was already identified in the initial stage of a myelodysplastic syndrome. BRCC3 mutations commonly occurred in nonsense (n=12), frameshift (n=4), and splice site (n=5) configurations. Due to the marginal male dominance (odds ratio; 2.00, 0.84-4.73) of BRCC3 mutations, the majority of mutations (n=23; 82%) were hemizygous. Phenotypically, BRCC3 mutations were frequently observed in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms and associated with -Y abnormality (odds ratio; 3.70, 1.25-11.0). Clinically, BRCC3 mutations were also related to higher age (P=0.01), although prognosis was not affected. Knockdown of Brcc3 gene expression in murine bone marrow lineage negative, Sca1 positive, c-kit positive cells resulted in 2-fold more colony formation and modest differentiation defect. Thus, BRCC3 likely plays a role as tumor-associated gene in myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms.
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Affiliation(s)
- Dayong Huang
- Department of Hematology, Beijing Friendship Hospital, Capital Medical University, Beijing, China Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Yasunobu Nagata
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | | | - Tomas Radivoyevitch
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - Yusuke Okuno
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | - Genta Nagae
- Genome Science Division, Research Center for Advanced Science and Technology, The University of Tokyo, Japan
| | - Naoko Hosono
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Masashi Sanada
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | - Bartlomiej Przychodzen
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Ayana Kon
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | - Chantana Polprasert
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Wenyi Shen
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Michael J Clemente
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | - James G Phillips
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Kenichi Yoshida
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | | | - Mikkael A Sekeres
- Leukemia Program, Taussig Cancer Institute, Cleveland Clinic, OH, USA
| | - Kevin Oakley
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Nhu Nguyen
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Yuichi Shiraishi
- Laboratory of DNA Information Analysis, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan
| | - Yusuke Shiozawa
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | - Kenichi Chiba
- Laboratory of DNA Information Analysis, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan
| | - Hiroko Tanaka
- Laboratory of Sequence Analysis, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan
| | - H Phillip Koeffler
- Department of Hematology/Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA Cancer Science Institute of Singapore, National University of Singapore
| | | | - Martin Dugas
- Institute of Medical Informatics, University of Münster, Germany
| | - Hiroyuki Aburatani
- Genome Science Division, Research Center for Advanced Science and Technology, The University of Tokyo, Japan
| | - Satoru Miyano
- Laboratory of DNA Information Analysis, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan Laboratory of Sequence Analysis, Human Genome Center, Institute of Medical Science, The University of Tokyo, Japan
| | | | | | | | - Yang Du
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Seishi Ogawa
- Department of Pathology and Tumor Biology, Kyoto University, Japan
| | - Hideki Makishima
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA Department of Pathology and Tumor Biology, Kyoto University, Japan
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ENGIN HBILLUR, HOFREE MATAN, CARTER HANNAH. Identifying mutation specific cancer pathways using a structurally resolved protein interaction network. PACIFIC SYMPOSIUM ON BIOCOMPUTING. PACIFIC SYMPOSIUM ON BIOCOMPUTING 2015; 20:84-95. [PMID: 25592571 PMCID: PMC4299875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Here we present a method for extracting candidate cancer pathways from tumor 'omics data while explicitly accounting for diverse consequences of mutations for protein interactions. Disease-causing mutations are frequently observed at either core or interface residues mediating protein interactions. Mutations at core residues frequently destabilize protein structure while mutations at interface residues can specifically affect the binding energies of protein-protein interactions. As a result, mutations in a protein may result in distinct interaction profiles and thus have different phenotypic consequences. We describe a protein structure-guided pipeline for extracting interacting protein sets specific to a particular mutation. Of 59 cancer genes with 3D co-complexed structures in the Protein Data Bank, 43 showed evidence of mutations with different functional consequences. Literature survey reciprocated functional predictions specific to distinct mutations on APC, ATRX, BRCA1, CBL and HRAS. Our analysis suggests that accounting for mutation-specific perturbations to cancer pathways will be essential for personalized cancer therapy.
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Affiliation(s)
- H. BILLUR ENGIN
- School of Medicine, University of California San Diego, 9500 Gilman Dr. San Diego, CA 92093, USA
| | - MATAN HOFREE
- Department of Computer Science and Engineering, University of California San Diego, 9500 Gilman Dr. San Diego, CA 92093, USA
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Wang L, Yamaguchi S, Burstein MD, Terashima K, Chang K, Ng HK, Nakamura H, He Z, Doddapaneni H, Lewis L, Wang M, Suzuki T, Nishikawa R, Natsume A, Terasaka S, Dauser R, Whitehead W, Adekunle A, Sun J, Qiao Y, Marth G, Muzny DM, Gibbs RA, Leal SM, Wheeler DA, Lau CC. Novel somatic and germline mutations in intracranial germ cell tumours. Nature 2014; 511:241-5. [PMID: 24896186 DOI: 10.1038/nature13296] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 03/28/2014] [Indexed: 12/12/2022]
Abstract
Intracranial germ cell tumours (IGCTs) are a group of rare heterogeneous brain tumours that are clinically and histologically similar to the more common gonadal GCTs. IGCTs show great variation in their geographical and gender distribution, histological composition and treatment outcomes. The incidence of IGCTs is historically five- to eightfold greater in Japan and other East Asian countries than in Western countries, with peak incidence near the time of puberty. About half of the tumours are located in the pineal region. The male-to-female incidence ratio is approximately 3-4:1 overall, but is even higher for tumours located in the pineal region. Owing to the scarcity of tumour specimens available for research, little is currently known about this rare disease. Here we report the analysis of 62 cases by next-generation sequencing, single nucleotide polymorphism array and expression array. We find the KIT/RAS signalling pathway frequently mutated in more than 50% of IGCTs, including novel recurrent somatic mutations in KIT, its downstream mediators KRAS and NRAS, and its negative regulator CBL. Novel somatic alterations in the AKT/mTOR pathway included copy number gains of the AKT1 locus at 14q32.33 in 19% of patients, with corresponding upregulation of AKT1 expression. We identified loss-of-function mutations in BCORL1, a transcriptional co-repressor and tumour suppressor. We report significant enrichment of novel and rare germline variants in JMJD1C, which codes for a histone demethylase and is a coactivator of the androgen receptor, among Japanese IGCT patients. This study establishes a molecular foundation for understanding the biology of IGCTs and suggests potentially promising therapeutic strategies focusing on the inhibition of KIT/RAS activation and the AKT1/mTOR pathway.
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Affiliation(s)
- Linghua Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shigeru Yamaguchi
- Texas Children's Cancer and Hematology Centers, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Matthew D Burstein
- 1] Structural and Computational Biology and Molecular Biophysics Program, Baylor College of Medicine, Houston, Texas 77030, USA [2] Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Keita Terashima
- 1] Texas Children's Cancer and Hematology Centers, Baylor College of Medicine, Houston, Texas 77030, USA [2] National Center for Child Health and Development, Tokyo, 157-8535, Japan
| | - Kyle Chang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Ho-Keung Ng
- Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Hideo Nakamura
- Department of Neurosurgery, Kumamoto University, Kumamoto, 860-0862, Japan
| | - Zongxiao He
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | - Lora Lewis
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Mark Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Tomonari Suzuki
- Department of Neurosurgery, Saitama Medical University, Saitama, 350-0495, Japan
| | - Ryo Nishikawa
- Department of Neurosurgery, Saitama Medical University, Saitama, 350-0495, Japan
| | - Atsushi Natsume
- Department of Neurosurgery, Nagoya University, Nagoya, 466-8550, Japan
| | - Shunsuke Terasaka
- Department of Neurosurgery, Hokkaido University, Hokkaido Prefecture, 060-0808, Japan
| | - Robert Dauser
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA
| | - William Whitehead
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Adesina Adekunle
- Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Jiayi Sun
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Yi Qiao
- Department of Biology, Boston College, Chestnut Hill, Maryland 02467, USA
| | - Gábor Marth
- Department of Biology, Boston College, Chestnut Hill, Maryland 02467, USA
| | - Donna M Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - David A Wheeler
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Ching C Lau
- 1] Texas Children's Cancer and Hematology Centers, Baylor College of Medicine, Houston, Texas 77030, USA [2] Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas 77030, USA [3] Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA
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Dasatinib targets B-lineage cells but does not provide an effective therapy for myeloproliferative disease in c-Cbl RING finger mutant mice. PLoS One 2014; 9:e94717. [PMID: 24718698 PMCID: PMC3981816 DOI: 10.1371/journal.pone.0094717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/18/2014] [Indexed: 11/30/2022] Open
Abstract
This study aimed to determine whether the multi-kinase inhibitor dasatinib would provide an effective therapy for myeloproliferative diseases (MPDs) involving c-Cbl mutations. These mutations, which occur in the RING finger and linker domains, abolish the ability of c-Cbl to function as an E3 ubiquitin ligase and downregulate activated protein tyrosine kinases. Here we analyzed the effects of dasatinib in a c-Cbl RING finger mutant mouse that develops an MPD with a phenotype similar to the human MPDs. The mice are characterized by enhanced tyrosine kinase signaling resulting in an expansion of hematopoietic stem cells, multipotent progenitors and cells within the myeloid lineage. Since c-Cbl is a negative regulator of c-Kit and Src signaling we reasoned that dasatinib, which targets these kinases, would be an effective therapy. Furthermore, two recent studies showed dasatinib to be effective in inhibiting the in vitro growth of cells from leukemia patients with c-Cbl RING finger and linker domain mutations. Surprisingly we found that dasatinib did not provide an effective therapy for c-Cbl RING finger mutant mice since it did not suppress any of the hematopoietic lineages that promote MPD development. Thus we conclude that dasatinib may not be an appropriate therapy for leukemia patients with c-Cbl mutations. We did however find that dasatinib caused a marked reduction of pre-B cells and immature B cells which correlated with a loss of Src activity. This study is therefore the first to provide a detailed characterization of in vivo effects of dasatinib in a hematopoietic disorder that is driven by protein tyrosine kinases other than BCR-ABL.
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Somatic SETBP1 mutations in myeloid malignancies. Nat Genet 2013; 45:942-6. [PMID: 23832012 PMCID: PMC3729750 DOI: 10.1038/ng.2696] [Citation(s) in RCA: 196] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 06/13/2013] [Indexed: 12/14/2022]
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Williams CB, Kambhampati S, Fiskus W, Wick J, Dutreix C, Ganguly S, Aljitawi O, Reyes R, Fleming A, Abhyankar S, Bhalla KN, McGuirk JP. Preclinical and phase I results of decitabine in combination with midostaurin (PKC412) for newly diagnosed elderly or relapsed/refractory adult patients with acute myeloid leukemia. Pharmacotherapy 2013; 33:1341-52. [PMID: 23798029 DOI: 10.1002/phar.1316] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE To determine the preclinical activity, clinical maximum tolerated dose (MTD), and recommended phase II dose of midostaurin (MS) combined either sequentially or concurrently with intravenous decitabine (DAC) in newly diagnosed patients 60 years or older or relapsed/refractory adult patients (18 years or older) with acute myeloid leukemia (AML). PATIENTS AND METHODS Cultured and primary AML cells were treated with DAC and/or MS and analyzed by flow cytometry and immunoblot analyses. In the phase I study, 16 patients were enrolled; 8 were newly diagnosed patients 60 years or older and 8 were 18 years or older with relapsed AML. Only 2 of 16 patients (13%) had FLT3-internal tandem duplication (ITD) mutations, and no patient had KIT mutations. RESULTS Compared with treatment with either agent alone, sequential treatment with DAC and MS exerted superior anti-AML activity in cultured and primary FLT3-ITD-expressing AML cells. In the subsequent phase I study, the MTD and schedule of administration of the combination was identified as DAC followed by MS. Three patients developed dose-limiting toxicities: two patients developed pulmonary edema requiring mechanical ventilation and one patient developed a prolonged QTc greater than 500 msec. Based on an intent-to-treat analysis, 57% of the patients achieved stable disease or better while enrolled in the trial; 25% had a complete hematologic response. Pharmacokinetic analysis revealed results similar to those previously reported for MS. CONCLUSION The in vitro combination of DAC and MS is synergistically active against FLT3-ITD mutations expressing AML cells. In a clinical setting, the combination of sequentially administered DAC followed by MS is possible without significant unexpected toxicity, but the concurrent administration of DAC and MS led to pulmonary toxicity after only a few doses. On the basis of these results, additional studies exploring the sequential combination of untreated AML in elderly patients are warranted to further evaluate this combination at the MTD.
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Mohapatra B, Ahmad G, Nadeau S, Zutshi N, An W, Scheffe S, Dong L, Feng D, Goetz B, Arya P, Bailey TA, Palermo N, Borgstahl GEO, Natarajan A, Raja SM, Naramura M, Band V, Band H. Protein tyrosine kinase regulation by ubiquitination: critical roles of Cbl-family ubiquitin ligases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:122-39. [PMID: 23085373 DOI: 10.1016/j.bbamcr.2012.10.010] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/05/2012] [Accepted: 10/08/2012] [Indexed: 12/20/2022]
Abstract
Protein tyrosine kinases (PTKs) coordinate a broad spectrum of cellular responses to extracellular stimuli and cell-cell interactions during development, tissue homeostasis, and responses to environmental challenges. Thus, an understanding of the regulatory mechanisms that ensure physiological PTK function and potential aberrations of these regulatory processes during diseases such as cancer are of broad interest in biology and medicine. Aside from the expected role of phospho-tyrosine phosphatases, recent studies have revealed a critical role of covalent modification of activated PTKs with ubiquitin as a critical mechanism of their negative regulation. Members of the Cbl protein family (Cbl, Cbl-b and Cbl-c in mammals) have emerged as dominant "activated PTK-selective" ubiquitin ligases. Structural, biochemical and cell biological studies have established that Cbl protein-dependent ubiquitination targets activated PTKs for degradation either by facilitating their endocytic sorting into lysosomes or by promoting their proteasomal degradation. This mechanism also targets PTK signaling intermediates that become associated with Cbl proteins in a PTK activation-dependent manner. Cellular and animal studies have established that the relatively broadly expressed mammalian Cbl family members Cbl and Cbl-b play key physiological roles, including their critical functions to prevent the transition of normal immune responses into autoimmune disease and as tumor suppressors; the latter function has received validation from human studies linking mutations in Cbl to human leukemia. These newer insights together with embryonic lethality seen in mice with a combined deletion of Cbl and Cbl-b genes suggest an unappreciated role of the Cbl family proteins, and by implication the ubiquitin-dependent control of activated PTKs, in stem/progenitor cell maintenance. Future studies of existing and emerging animal models and their various cell lineages should help test the broader implications of the evolutionarily-conserved Cbl family protein-mediated, ubiquitin-dependent, negative regulation of activated PTKs in physiology and disease.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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Mohapatra B, Ahmad G, Nadeau S, Zutshi N, An W, Scheffe S, Dong L, Feng D, Goetz B, Arya P, Bailey TA, Palermo N, Borgstahl GEO, Natarajan A, Raja SM, Naramura M, Band V, Band H. Protein tyrosine kinase regulation by ubiquitination: critical roles of Cbl-family ubiquitin ligases. BIOCHIMICA ET BIOPHYSICA ACTA 2012. [PMID: 23085373 DOI: 10.1016/j.bbamcr] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Protein tyrosine kinases (PTKs) coordinate a broad spectrum of cellular responses to extracellular stimuli and cell-cell interactions during development, tissue homeostasis, and responses to environmental challenges. Thus, an understanding of the regulatory mechanisms that ensure physiological PTK function and potential aberrations of these regulatory processes during diseases such as cancer are of broad interest in biology and medicine. Aside from the expected role of phospho-tyrosine phosphatases, recent studies have revealed a critical role of covalent modification of activated PTKs with ubiquitin as a critical mechanism of their negative regulation. Members of the Cbl protein family (Cbl, Cbl-b and Cbl-c in mammals) have emerged as dominant "activated PTK-selective" ubiquitin ligases. Structural, biochemical and cell biological studies have established that Cbl protein-dependent ubiquitination targets activated PTKs for degradation either by facilitating their endocytic sorting into lysosomes or by promoting their proteasomal degradation. This mechanism also targets PTK signaling intermediates that become associated with Cbl proteins in a PTK activation-dependent manner. Cellular and animal studies have established that the relatively broadly expressed mammalian Cbl family members Cbl and Cbl-b play key physiological roles, including their critical functions to prevent the transition of normal immune responses into autoimmune disease and as tumor suppressors; the latter function has received validation from human studies linking mutations in Cbl to human leukemia. These newer insights together with embryonic lethality seen in mice with a combined deletion of Cbl and Cbl-b genes suggest an unappreciated role of the Cbl family proteins, and by implication the ubiquitin-dependent control of activated PTKs, in stem/progenitor cell maintenance. Future studies of existing and emerging animal models and their various cell lineages should help test the broader implications of the evolutionarily-conserved Cbl family protein-mediated, ubiquitin-dependent, negative regulation of activated PTKs in physiology and disease.
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Affiliation(s)
- Bhopal Mohapatra
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
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