Sprouty 2: a novel attenuator of B-cell receptor and MAPK-Erk signaling in CLL.
Blood
; 127(19): 2310-21, 2016 05 12.
Article
em En
| MEDLINE
| ID: mdl-26809508
ABSTRACT
Clinical heterogeneity is a major barrier to effective treatment of chronic lymphocytic leukemia (CLL). Emerging evidence suggests that constitutive activation of various signaling pathways like mitogen-activated protein kinase-extracellular signal-regulated kinase (MAPK-Erk) signaling plays a role in the heterogeneous clinical outcome of CLL patients. In this study, we have investigated the role of Sprouty (SPRY)2 as a negative regulator of receptor and nonreceptor tyrosine kinase signaling in the pathogenesis of CLL. We show that SPRY2 expression is significantly decreased in CLL cells, particularly from poor-prognosis patients compared with those from good-prognosis patients. Overexpression of SPRY2 in CLL cells from poor-prognosis patients increased their apoptosis. Conversely, downregulation of SPRY2 in CLL cells from good-prognosis patients resulted in increased proliferation. Furthermore, CLL cells with low SPRY2 expression grew more rapidly in a xenograft model of CLL. Strikingly, B-cell-specific transgenic overexpression of spry2 in mice led to a decrease in the frequency of B1 cells, the precursors of CLL cells in rodents. Mechanistically, we show that SPRY2 attenuates the B-cell receptor (BCR) and MAPK-Erk signaling by binding to and antagonizing the activities of RAF1, BRAF, and spleen tyrosine kinase (SYK) in normal B cells and CLL cells. We also show that SPRY2 is targeted by microRNA-21, which in turn leads to increased activity of Syk and Erk in CLL cells. Taken together, these results establish SPRY2 as a critical negative regulator of BCR-mediated MAPK-Erk signaling in CLL, thereby providing one of the molecular mechanisms to explain the clinical heterogeneity of CLL.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
6_ODS3_enfermedades_notrasmisibles
Base de dados:
MEDLINE
Assunto principal:
Linfócitos B
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Receptores de Antígenos de Linfócitos B
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Leucemia Linfocítica Crônica de Células B
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Regulação Leucêmica da Expressão Gênica
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Sistema de Sinalização das MAP Quinases
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Peptídeos e Proteínas de Sinalização Intracelular
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Proliferação de Células
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Proteínas de Membrana
Limite:
Animals
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Female
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Humans
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Male
Idioma:
En
Revista:
Blood
Ano de publicação:
2016
Tipo de documento:
Article