Activation of RHOA-VAV1 signaling in angioimmunoblastic T-cell lymphoma.
Leukemia
; 32(3): 694-702, 2018 03.
Article
de 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.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Transduction du signal
/
Lymphome T
/
Protéine G RhoA
/
Protéines proto-oncogènes c-vav
/
Lymphadénopathie angio-immunoblastique
Type d'étude:
Prognostic_studies
Limites:
Humans
Langue:
En
Journal:
Leukemia
Sujet du journal:
HEMATOLOGIA
/
NEOPLASIAS
Année:
2018
Type de document:
Article
Pays d'affiliation:
Japon