Inhibition of the ATR kinase enhances 5-FU sensitivity independently of nonhomologous end-joining and homologous recombination repair pathways.
J Biol Chem
; 295(37): 12946-12961, 2020 09 11.
Article
em En
| MEDLINE
| ID: mdl-32675286
ABSTRACT
The anticancer agent 5-fluorouracil (5-FU) is cytotoxic and often used to treat various cancers. 5-FU is thought to inhibit the enzyme thymidylate synthase, which plays a role in nucleotide synthesis and has been found to induce single- and double-strand DNA breaks. ATR Ser/Thr kinase (ATR) is a principal kinase in the DNA damage response and is activated in response to UV- and chemotherapeutic drug-induced DNA replication stress, but its role in cellular responses to 5-FU is unclear. In this study, we examined the effect of ATR inhibition on 5-FU sensitivity of mammalian cells. Using immunoblotting, we found that 5-FU treatment dose-dependently induced the phosphorylation of ATR at the autophosphorylation site Thr-1989 and thereby activated its kinase. Administration of 5-FU with a specific ATR inhibitor remarkably decreased cell survival, compared with 5-FU treatment combined with other major DNA repair kinase inhibitors. Of note, the ATR inhibition enhanced induction of DNA double-strand breaks and apoptosis in 5-FU-treated cells. Using gene expression analysis, we found that 5-FU induced the activation of the intra-S cell-cycle checkpoint. Cells lacking BRCA2 were sensitive to 5-FU in the presence of ATR inhibitor. Moreover, ATR inhibition enhanced the efficacy of the 5-FU treatment, independently of the nonhomologous end-joining and homologous recombination repair pathways. These findings suggest that ATR could be a potential therapeutic target in 5-FU-based chemotherapy.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Resistencia a Medicamentos Antineoplásicos
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Inibidores de Proteínas Quinases
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Reparo do DNA por Junção de Extremidades
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Reparo de DNA por Recombinação
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Proteínas Mutadas de Ataxia Telangiectasia
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Fluoruracila
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Proteínas de Neoplasias
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Neoplasias
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Japão