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Tvorogov D, Thompson-Peach CAL, Foßelteder J, Dottore M, Stomski F, Onnesha SA, Lim K, Moretti PAB, Pitson SM, Ross DM, Reinisch A, Thomas D, Lopez AF. Targeting human CALR-mutated MPN progenitors with a neoepitope-directed monoclonal antibody. EMBO Rep 2022; 23:e52904. [PMID: 35156745 PMCID: PMC8982588 DOI: 10.15252/embr.202152904] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 01/23/2022] [Accepted: 01/26/2022] [Indexed: 01/02/2023] Open
Abstract
Calreticulin (CALR) is recurrently mutated in myelofibrosis via a frameshift that removes an endoplasmic reticulum retention signal, creating a neoepitope potentially targetable by immunotherapeutic approaches. We developed a specific rat monoclonal IgG2α antibody, 4D7, directed against the common sequence encoded by both insertion and deletion mutations. 4D7 selectively bound to cells co‐expressing mutant CALR and thrombopoietin receptor (TpoR) and blocked JAK‐STAT signalling, TPO‐independent proliferation and megakaryocyte differentiation of mutant CALR myelofibrosis progenitors by disrupting the binding of CALR dimers to TpoR. Importantly, 4D7 inhibited proliferation of patient samples with both insertion and deletion CALR mutations but not JAK2 V617F and prolonged survival in xenografted bone marrow models of mutant CALR‐dependent myeloproliferation. Together, our data demonstrate a novel therapeutic approach to target a problematic disease driven by a recurrent somatic mutation that would normally be considered undruggable.
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Affiliation(s)
- Denis Tvorogov
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Chloe A L Thompson-Peach
- Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide, Adelaide, SA, Australia.,Discipline of Medicine, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Johannes Foßelteder
- Department of Internal Medicine, Division of Haematology, Medical University of Graz, Graz, Austria
| | - Mara Dottore
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Frank Stomski
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Suraiya A Onnesha
- Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide, Adelaide, SA, Australia.,Discipline of Medicine, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Kelly Lim
- Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide, Adelaide, SA, Australia.,Discipline of Medicine, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Paul A B Moretti
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia
| | - Stuart M Pitson
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia.,Discipline of Medicine, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - David M Ross
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide, Adelaide, SA, Australia.,Department of Haematology, Flinders University and Medical Centre, Adelaide, SA, Australia
| | - Andreas Reinisch
- Department of Internal Medicine, Division of Haematology, Medical University of Graz, Graz, Austria.,Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | - Daniel Thomas
- Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute (SAHMRI), University of Adelaide, Adelaide, SA, Australia.,Discipline of Medicine, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Angel F Lopez
- Centre for Cancer Biology, SA Pathology and University of South Australia, Adelaide, SA, Australia.,Discipline of Medicine, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
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Roy A, Shrivastva S, Naseer S. In and out: Traffic and dynamics of thrombopoietin receptor. J Cell Mol Med 2021; 25:9073-9083. [PMID: 34448528 PMCID: PMC8500957 DOI: 10.1111/jcmm.16878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/27/2021] [Accepted: 08/04/2021] [Indexed: 12/17/2022] Open
Abstract
Thrombopoiesis had long been a challenging area of study due to the rarity of megakaryocyte precursors in the bone marrow and the incomplete understanding of its regulatory cytokines. A breakthrough was achieved in the early 1990s with the discovery of the thrombopoietin receptor (TpoR) and its ligand thrombopoietin (TPO). This accelerated research in thrombopoiesis, including the uncovering of the molecular basis of myeloproliferative neoplasms (MPN) and the advent of drugs to treat thrombocytopenic purpura. TpoR mutations affecting its membrane dynamics or transport were increasingly associated with pathologies such as MPN and thrombocytosis. It also became apparent that TpoR affected hematopoietic stem cell (HSC) quiescence while priming hematopoietic stem cells (HSCs) towards the megakaryocyte lineage. Thorough knowledge of TpoR surface localization, dimerization, dynamics and stability is therefore crucial to understanding thrombopoiesis and related pathologies. In this review, we will discuss the mechanisms of TpoR traffic. We will focus on the recent progress in TpoR membrane dynamics and highlight the areas that remain unexplored.
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Affiliation(s)
- Anita Roy
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
| | - Saurabh Shrivastva
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
| | - Saadia Naseer
- Kusuma School of Biological Sciences, Indian Institute of Technology, New Delhi, India
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