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Cozma D, Yu D, Hodawadekar S, Azvolinsky A, Grande S, Tobias JW, Metzgar MH, Paterson J, Erikson J, Marafioti T, Monroe JG, Atchison ML, Thomas-Tikhonenko A. B cell activator PAX5 promotes lymphomagenesis through stimulation of B cell receptor signaling. J Clin Invest 2007; 117:2602-10. [PMID: 17717600 PMCID: PMC1950455 DOI: 10.1172/jci30842] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Accepted: 05/29/2007] [Indexed: 01/16/2023] Open
Abstract
The presumed involvement of paired box gene 5 (PAX5) in B-lymphomagenesis is based largely on the discovery of Pax5-specific translocations and somatic hypermutations in non-Hodgkin lymphomas. Yet mechanistically, the contribution of Pax5 to neoplastic growth remains undeciphered. Here we used 2 Myc-induced mouse B lymphoma cell lines, Myc5-M5 and Myc5-M12, which spontaneously silence Pax5. Reconstitution of these cells with Pax5-tamoxifen receptor fusion protein (Pax5ER(TAM)) increased neoplastic growth in a hormone-dependent manner. Conversely, expression of dominant-negative Pax5 in murine lymphomas and Pax5 knockdown in human lymphomas negatively affected cell expansion. Expression profiling revealed that Pax5 was required to maintain mRNA levels of several crucial components of B cell receptor (BCR) signaling, including CD79a, a protein with the immunoreceptor tyrosine-based activation motif (ITAM). In contrast, expression of 2 known ITAM antagonists, CD22 and PIR-B, was suppressed. The key role of BCR/ITAM signaling in Pax5-dependent lymphomagenesis was corroborated in Syk, an ITAM-associated tyrosine kinase. Moreover, we observed consistent expression of phosphorylated BLNK, an activated BCR adaptor protein, in human B cell lymphomas. Thus, stimulation of neoplastic growth by Pax5 occurs through BCR and is sensitive to genetic and pharmacological inhibitors of this pathway.
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Affiliation(s)
- Diana Cozma
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Duonan Yu
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Suchita Hodawadekar
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Anna Azvolinsky
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Shannon Grande
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - John W. Tobias
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Michele H. Metzgar
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Jennifer Paterson
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Jan Erikson
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Teresa Marafioti
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - John G. Monroe
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Michael L. Atchison
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
| | - Andrei Thomas-Tikhonenko
- Department of Pathobiology and
Department of Animal Biology, School of Veterinary Medicine,
Department of Pathology and Laboratory Medicine, School of Medicine, and
Biomedical Informatics Core, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
The Wistar Institute, Philadelphia, Pennsylvania, USA.
Leukaemia Research Fund Immunodiagnostics Unit, Nuffield Department of Clinical Laboratory Sciences, John Radcliffe Hospital, Oxford, United Kingdom
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