GSK-3ß controls autophagy by modulating LKB1-AMPK pathway in prostate cancer cells.
Prostate
; 76(2): 172-83, 2016 Feb.
Article
em En
| MEDLINE
| ID: mdl-26440826
ABSTRACT
BACKGROUND:
Glycogen synthase kinase 3ß (GSK3B, GSK-3ß) is a multi-functional protein kinase involved in various cellular processes and its activity elevates after serum deprivation. We have shown that inhibition of GSK-3ß activity triggered a profound autophagic response and subsequent necrotic cell death after serum deprivation in prostate cancer cells. In this study, we dissected the mechanisms involved in GSK-3ß inhibition-triggered autophagy.METHODS:
Prostate cancer PC-3 and DU145 cells were used in the study. Multiple GSK-3ß specific inhibitors were used including small chemicals TDZD8, Tideglusib, TWS119, and peptide L803-mts. Western blot assay coupled with phospho-specific antibodies were used in detecting signal pathway activation. ATP levels were assessed with ATPLite kit and HPLC methods. Autophagy response was determined by evaluating Microtubule-associated proteins 1A/1B light chain 3B (LC3B) processing and p62 protein stability in Western blot assays. Immunofluorescent microscopy was used to detect LKB1 translocation.RESULTS:
Inhibition of GSK-3ß activity resulted in a significant decline of cellular ATP production, leading to a significant increase of AMP/ATP ratio, a strong trigger of AMP-activated protein kinase (AMPK) activation in prostate cancer PC-3 cells. In parallel with increased LC-3B biosynthesis and p62 protein reduction, the classical sign of autophagy induction, AMPK was activated after inhibition of GSK-3ß activity. Further analysis revealed that Liver kinase B1 (LKB1) but not Calcium/calmodulin-dependent protein kinase kinase ß (CaMKKß) is involved in AMPK activation and autophagy induction triggered by GSK-3ß inhibition. Meanwhile, GSK-3ß inhibition promoted LKB1 translocation from nuclear to cytoplasmic compartment and enhanced LKB1 interaction with its regulatory partners Mouse protein-25 (MO25) and STE20-related adaptor (STRAD).CONCLUSIONS:
In conclusion, our data suggest that GSK-3ß plays an important role in controlling autophagy induction by modulating the activation of LKB1-AMPK pathway after serum deprivation.Palavras-chave
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Próstata
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Autofagia
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Transdução de Sinais
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Proteínas Serina-Treonina Quinases
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Quinase 3 da Glicogênio Sintase
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Proteínas Quinases Ativadas por AMP
Limite:
Animals
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Humans
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Male
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article