Hsp90-inhibitor geldanamycin abrogates G2 arrest in p53-negative leukemia cell lines through the depletion of Chk1.
Oncogene
; 27(22): 3091-101, 2008 May 15.
Article
em En
| MEDLINE
| ID: mdl-18071310
ABSTRACT
Checkpoint protein Chk1 has been identified as an Hsp90 client. Treatment with 100 nM geldanamycin (GM) for 24 h markedly reduced the Chk1 amount in Jurkat and ML-1 leukemia cell lines. Because Chk1 plays a central role in G2 checkpoint, we added GM to G2-arrested Jurkat and HL-60 cells pretreated with 50 nM doxorubicin for 24 h. GM slowly released both cell lines from doxorubicin-induced G2 arrest into G1 phase. GM also abrogated ICRF-193-induced decatenation G2 checkpoint in Jurkat and HL-60 cells. Western blot analysis showed that addition of GM attenuates doxorubicin- and ICRF-193-induced Chk1 phosphorylation at Ser345. GM, however, failed to abrogate G2 arrest in p53-positive ML-1 cells maybe due to the p21 induction. GM released HeLa cells from doxorubicin-induced G2 arrest but trapped them at M phase. Flow cytometric analysis showed that addition of GM converted doxorubicin-induced necrosis into apoptosis in Jurkat cells. Colony assay indicated that although GM has a weak cytotoxic effect as a single agent, it dramatically intensifies the cytotoxicity of doxorubicin and ICRF-193 in Jurkat and HL-60 cells. These results suggest that abrogation of G2 checkpoint by GM may play a central role in sensitizing p53-negative tumor cells to DNA-damaging and decatenation-inhibiting agents.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas Quinases
/
Leucemia
/
Benzoquinonas
/
Fase G2
/
Lactamas Macrocíclicas
/
Proliferação de Células
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article