Tumor Necrosis Factor Receptor-Associated Factor 6 Promotes Hepatocarcinogenesis by Interacting With Histone Deacetylase 3 to Enhance c-Myc Gene Expression and Protein Stability.
Hepatology
; 71(1): 148-163, 2020 01.
Article
em En
| MEDLINE
| ID: mdl-31155734
ABSTRACT
The oncogene c-Myc is aberrantly expressed and plays a key role in malignant transformation and progression of hepatocellular carcinoma (HCC). Here, we report that c-Myc is significantly up-regulated by tumor necrosis factor receptor-associated factor 6 (TRAF6), an E3 ubiquitin ligase, in hepatocarcinogenesis. High TRAF6 expression in clinical HCC samples correlates with poor prognosis, and the loss of one copy of the Traf6 gene in Traf6+/- mice significantly impairs liver tumorigenesis. Mechanistically, TRAF6 first interacts with and ubiquitinates histone deacetylase 3 (HDAC3) with K63-linked ubiquitin chains, which leads to the dissociation of HDAC3 from the c-Myc promoter and subsequent acetylation of histone H3 at K9, thereby epigenetically enhancing the mRNA expression of c-Myc. Second, the K63-linked ubiquitination of HDAC3 impairs the HDAC3 interaction with c-Myc and promotes c-Myc protein acetylation, which thereby enhances c-Myc protein stability by inhibiting carboxyl terminus of heat shock cognate 70-kDa-interacting protein-mediated c-Myc ubiquitination and degradation. Importantly, TRAF6/HDAC3/c-Myc signaling is also primed in hepatitis B virus-transgenic mice, unveiling a critical role for a mechanism in inflammation-cancer transition. In clinical specimens, TRAF6 positively correlates with c-Myc at both the mRNA and protein levels, and high TRAF6 and c-Myc expression is associated with an unfavorable prognosis, suggesting that TRAF6 collaborates with c-Myc to promote human hepatocarcinogenesis. Consistently, curbing c-Myc expression by inhibition of TRAF6 activity with a TRAF6 inhibitor peptide or the silencing of c-Myc by small interfering RNA significantly suppressed tumor growth in mice. Conclusion:
These findings demonstrate the oncogenic potential of TRAF6 during hepatocarcinogenesis by modulating TRAF6/HDAC3/c-Myc signaling, with potential implications for HCC therapy.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Genes myc
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Carcinoma Hepatocelular
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Fator 6 Associado a Receptor de TNF
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Carcinogênese
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Histona Desacetilases
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Neoplasias Hepáticas
Tipo de estudo:
Prognostic_studies
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Risk_factors_studies
Limite:
Animals
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Humans
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Male
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article