Inhibition of Lck enhances glucocorticoid sensitivity and apoptosis in lymphoid cell lines and in chronic lymphocytic leukemia.
Cell Death Differ
; 17(9): 1381-91, 2010 Sep.
Article
em En
| MEDLINE
| ID: mdl-20300113
ABSTRACT
Glucocorticoids are used as part of front-line therapy to treat lymphoid malignancy because of their remarkable ability to induce apoptosis. Yet, in T cells, glucocorticoid-induced apoptosis is readily inhibited by lymphocyte activation and signaling. We have previously shown that the Src family kinase, Lck (lymphocyte cell-specific tyrosine kinase), which is predominantly expressed in T cells, interacts with IP3 receptors to facilitate calcium signaling. Here, we discovered that dexamethasone downregulates Lck, which, in turn, suppresses lymphocyte activation by inhibiting pro-survival calcium oscillations. Moreover, stable expression of shRNAs that selectively targeted Lck or treatment with the Src inhibitor dasatinib (BMS-354825) enhanced apoptosis induction by dexamethasone. To investigate the effect of Lck inhibition in a primary leukemia model, we employed chronic lymphocytic leukemia (CLL) cells that aberrantly expressed Lck and were relatively insensitive to dexamethasone. Lck expression was correlated with resistance to dexamethasone in CLL cells, and its inhibition by dasatinib or other inhibitors markedly enhanced glucocorticoid sensitivity. Collectively, these data indicate that Lck protects cells from glucocorticoid-induced apoptosis and its inhibition enhances sensitivity to dexamethasone. Small-molecule inhibitors of Lck, such as dasatinib, may function to reverse glucocorticoid resistance in some lymphoid malignancies.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Linfócitos
/
Leucemia Linfocítica Crônica de Células B
/
Apoptose
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Resistencia a Medicamentos Antineoplásicos
/
Proteína Tirosina Quinase p56(lck) Linfócito-Específica
/
Glucocorticoides
Tipo de estudo:
Diagnostic_studies
Idioma:
En
Revista:
Cell Death Differ
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Estados Unidos