Targeting RNA-Polymerase I in Both Chemosensitive and Chemoresistant Populations in Epithelial Ovarian Cancer.
Clin Cancer Res
; 23(21): 6529-6540, 2017 Nov 01.
Article
em En
| MEDLINE
| ID: mdl-28778862
ABSTRACT
Purpose:
A hallmark of neoplasia is increased ribosome biogenesis, and targeting this process with RNA polymerase I (Pol I) inhibitors has shown some efficacy. We examined the contribution and potential targeting of ribosomal machinery in chemotherapy-resistant and -sensitive models of ovarian cancer.ExperimentalDesign:
Pol I machinery expression was examined, and subsequently targeted with the Pol I inhibitor CX-5461, in ovarian cancer cell lines, an immortalized surface epithelial line, and patient-derived xenograft (PDX) models with and without chemotherapy. Effects on viability, Pol I occupancy of rDNA, ribosomal content, and chemosensitivity were examined.Results:
In PDX models, ribosomal machinery components were increased in chemotherapy-treated tumors compared with controls. Thirteen cell lines were sensitive to CX-5461, with IC50s 25 nmol/L-2 µmol/L. Interestingly, two chemoresistant lines were 10.5- and 5.5-fold more sensitive than parental lines. CX-5461 induced DNA damage checkpoint activation and G2-M arrest with increased γH2AX staining. Chemoresistant cells had 2- to 4-fold increased rDNA Pol I occupancy and increased rRNA synthesis, despite having slower proliferation rates, whereas ribosome abundance and translational efficiency were not impaired. In five PDX models treated with CX-5461, one showed a complete response, one a 55% reduction in tumor volume, and one maintained stable disease for 45 days.Conclusions:
Pol I inhibition with CX-5461 shows high activity in ovarian cancer cell lines and PDX models, with an enhanced effect on chemoresistant cells. Effects occur independent of proliferation rates or dormancy. This represents a novel therapeutic approach that may have preferential activity in chemoresistant populations. Clin Cancer Res; 23(21); 6529-40. ©2017 AACR.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Ovarianas
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Neoplasias Epiteliais e Glandulares
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Resistencia a Medicamentos Antineoplásicos
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Proliferação de Células
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Benzotiazóis
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Naftiridinas
Limite:
Animals
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Female
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Humans
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article