Acquired resistance to 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin) in glioblastoma cells.
Cancer Res
; 69(5): 1966-75, 2009 Mar 01.
Article
in En
| MEDLINE
| ID: mdl-19244114
ABSTRACT
Heat shock protein 90 (HSP90) inhibitors, such as 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin), which is currently in phase II/phase III clinical trials, are promising new anticancer agents. Here, we explored acquired resistance to HSP90 inhibitors in glioblastoma (GB), a primary brain tumor with poor prognosis. GB cells were exposed continuously to increased 17-AAG concentrations. Four 17-AAG-resistant GB cell lines were generated. High-resistance levels with resistance indices (RI = resistant line IC(50)/parental line IC(50)) of 20 to 137 were obtained rapidly (2-8 weeks). After cessation of 17-AAG exposure, RI decreased and then stabilized. Cross-resistance was found with other ansamycin benzoquinones but not with the structurally unrelated HSP90 inhibitors, radicicol, the purine BIIB021, and the resorcinylic pyrazole/isoxazole amide compounds VER-49009, VER-50589, and NVP-AUY922. An inverse correlation between NAD(P)H/quinone oxidoreductase 1 (NQO1) expression/activity and 17-AAG IC(50) was observed in the resistant lines. The NQO1 inhibitor ES936 abrogated the differential effects of 17-AAG sensitivity between the parental and resistant lines. NQO1 mRNA levels and NQO1 DNA polymorphism analysis indicated different underlying mechanisms reduced expression and selection of the inactive NQO1*2 polymorphism. Decreased NQO1 expression was also observed in a melanoma line with acquired resistance to 17-AAG. No resistance was generated with VER-50589 and NVP-AUY922. In conclusion, low NQO1 activity is a likely mechanism of acquired resistance to 17-AAG in GB, melanoma, and, possibly, other tumor types. Such resistance can be overcome with novel HSP90 inhibitors.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Benzoquinones
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Glioblastoma
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HSP90 Heat-Shock Proteins
/
Lactams, Macrocyclic
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Antineoplastic Agents
Limits:
Animals
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Female
/
Humans
Language:
En
Journal:
Cancer Res
Year:
2009
Document type:
Article
Affiliation country:
United kingdom