Activation of RHOA-VAV1 signaling in angioimmunoblastic T-cell lymphoma.
Leukemia
; 32(3): 694-702, 2018 03.
Article
en En
| MEDLINE
| ID: mdl-28832024
ABSTRACT
Somatic G17V RHOA mutations were found in 50-70% of angioimmunoblastic T-cell lymphoma (AITL). The mutant RHOA lacks GTP binding capacity, suggesting defects in the classical RHOA signaling. Here, we discovered the novel function of the G17V RHOA VAV1 was identified as a G17V RHOA-specific binding partner via high-throughput screening. We found that binding of G17V RHOA to VAV1 augmented its adaptor function through phosphorylation of 174Tyr, resulting in acceleration of T-cell receptor (TCR) signaling. Enrichment of cytokine and chemokine-related pathways was also evident by the expression of G17V RHOA. We further identified VAV1 mutations and a new translocation, VAV1-STAP2, in seven of the 85 RHOA mutation-negative samples (8.2%), whereas none of the 41 RHOA mutation-positive samples exhibited VAV1 mutations. Augmentation of 174Tyr phosphorylation was also demonstrated in VAV1-STAP2. Dasatinib, a multikinase inhibitor, efficiently blocked the accelerated VAV1 phosphorylation and the associating TCR signaling by both G17V RHOA and VAV1-STAP2 expression. Phospho-VAV1 staining was demonstrated in the clinical specimens harboring G17V RHOA and VAV1 mutations at a higher frequency than those without. Our findings indicate that the G17V RHOA-VAV1 axis may provide a new therapeutic target in AITL.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Transducción de Señal
/
Linfoma de Células T
/
Proteína de Unión al GTP rhoA
/
Proteínas Proto-Oncogénicas c-vav
/
Linfadenopatía Inmunoblástica
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Leukemia
Asunto de la revista:
HEMATOLOGIA
/
NEOPLASIAS
Año:
2018
Tipo del documento:
Article
País de afiliación:
Japón