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1.
Hepatology ; 75(4): 847-865, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34626132

RESUMO

BACKGROUND AND AIMS: The mechanism underlying HCC metastasis remains unclear, many oncogenes are known to regulate this process. However, the role of alternative splicing (AS) in pro-metastatic HCC is poorly understood. APPROACH AND RESULTS: By performing RNA sequencing on nine pairs of primary HCC tissues with extrahepatic metastasis (EHMH) and nine pairs of metastasis-free HCC (MFH) tissues, we depicted the AS landscape in HCC and found a higher frequency of AS events in EHMH compared with MFH. Moreover, 28 differentially expressed splicing regulators were identified in EHMH compared with MFH. Among these, DEAD-box RNA helicase 17 (DDX17) was significantly up-regulated in EHMH and was strongly associated with patient outcome. Functional studies indicated that DDX17 knockout inhibited the degradation of the extracellular matrix, and diminished the invasive ability of HCC cells. A significant reduction in lung metastasis induced by DDX17 deficiency was also demonstrated in a diethylnitrosamine-induced DDX17HKO mouse model. Mechanistically, high DDX17 induced intron 3 retention of PXN-AS1 and produced a transcript (termed PXN-AS1-IR3). The transcript PXN-AS1-IR3 acted as an important promoter of HCC metastasis by inducing MYC transcription activation via recruiting the complex of testis expressed 10 and p300 to the MYC enhancer region, which led to transcriptional activation of several metastasis-associated downstream genes. Finally, the PXN-AS1-IR3 level was significantly higher in serum and HCC tissues with extrahepatic metastasis. CONCLUSIONS: DDX17 and PXN-AS1-IR3 act as important metastatic promoters by modulating MYC signaling, suggesting that DDX17 and PXN-AS1-IR3 may be potential prognostic markers for metastatic HCC.


Assuntos
Carcinoma Hepatocelular , RNA Helicases DEAD-box , Neoplasias Hepáticas , MicroRNAs , RNA Longo não Codificante , Processamento Alternativo , Animais , Carcinogênese/genética , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , RNA Helicases DEAD-box/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/patologia , Masculino , Camundongos , MicroRNAs/genética , Metástase Neoplásica , Oncogenes , Isoformas de Proteínas/genética , Proteínas Proto-Oncogênicas c-myc/genética , RNA Longo não Codificante/genética , Transdução de Sinais
2.
Clin Sci (Lond) ; 135(12): 1505-1522, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34128977

RESUMO

Chronic hepatitis B virus (HBV) infection is a significant public health burden worldwide. HBV covalently closed circular DNA (cccDNA) organized as a minichromosome in nucleus is responsible for viral persistence and is the key obstacle for a cure of chronic hepatitis B (CHB). Recent studies suggest cccDNA transcription is epigenetically regulated by histone modifications, especially histone acetylation and methylation. In the present study, we identified transcriptionally active histone succinylation (H3K122succ) as a new histone modification on cccDNA minichromosome by using cccDNA ChIP-Seq approach. Silent mating type information regulation 2 homolog 7 (SIRT7), as an NAD+-dependent histone desuccinylase, could bind to cccDNA through interaction with HBV core protein where it catalyzed histone 3 lysine 122 (H3K122) desuccinylation. Moreover, SIRT7 acts cooperatively with histone methyltransferase, suppressor of variegation 3-9 homolog 1 (SUV39H1) and SET domain containing 2 (SETD2) to induce silencing of HBV transcription through modulation of chromatin structure. Our data improved the understanding of histone modifications of the cccDNA minichromosome, thus transcriptional silencing of cccDNA may represent a novel antiviral strategy for the prevention or treatment of HBV infection.


Assuntos
Catálise , DNA Circular/metabolismo , Histona Metiltransferases/genética , Histonas/metabolismo , Sirtuínas/metabolismo , DNA Viral/genética , Hepatite B/prevenção & controle , Hepatite B/terapia , Hepatite B/virologia , Vírus da Hepatite B/patogenicidade , Hepatite B Crônica/tratamento farmacológico , Hepatite B Crônica/prevenção & controle , Humanos , Sirtuínas/genética , Transcrição Gênica/genética , Replicação Viral/genética
3.
Front Microbiol ; 12: 795388, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35140694

RESUMO

Hepatitis B virus (HBV) infection remains a major health problem worldwide. Sufficient maintenance of the HBV covalently closed circular DNA (cccDNA), which serves as a template for HBV transcription, is responsible for the failure of antiviral therapies. While accumulating evidence suggests that cccDNA transcription is regulated by epigenetic machinery, particularly the acetylation and methylation of cccDNA-bound histone 3 (H3) and histone 4 (H4), the potential contributions of histone succinylation and related host factors remain obscured. Here, by screening a series of succinyltransferases and desuccinylases, we identified KAT2A as an important host factor of HBV transcription and replication. By using HBV-infected cells and mouse models with HBV infection, KAT2A was found to affect the transcriptional activity of cccDNA but did not affect cccDNA production. Mechanism studies showed that KAT2A is mainly located in the nucleus and could bind to cccDNA through interaction with HBV core protein (HBc). Moreover, we confirmed histone H3K79 succinylation (H3K79succ) as a histone modification on cccDNA minichromosome by using the cccDNA ChIP-Seq approach. Importantly, KAT2A silencing specifically reduced the level of cccDNA-bound succinylated H3K79. In conclusion, KAT2A promotes HBV transcription and replication through epigenetic machinery, and our findings may provide new insight into the treatment of HBV infection.

4.
J Hepatol ; 74(3): 522-534, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32987030

RESUMO

BACKGROUND & AIMS: Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx. METHODS: We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model. RESULTS: Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells. CONCLUSIONS: Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability. LAY SUMMARY: Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.


Assuntos
Antivirais/administração & dosagem , DNA Circular/metabolismo , Dicumarol/administração & dosagem , Vírus da Hepatite B/metabolismo , Hepatite B Crônica/tratamento farmacológico , Hepatite B Crônica/metabolismo , NAD(P)H Desidrogenase (Quinona)/antagonistas & inibidores , NAD(P)H Desidrogenase (Quinona)/metabolismo , Proteólise/efeitos dos fármacos , Transativadores/metabolismo , Transcrição Gênica/efeitos dos fármacos , Proteínas Virais Reguladoras e Acessórias/metabolismo , Animais , DNA Circular/isolamento & purificação , Modelos Animais de Doenças , Células Hep G2 , Vírus da Hepatite B/efeitos dos fármacos , Hepatite B Crônica/virologia , Hepatócitos/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , NAD(P)H Desidrogenase (Quinona)/genética , Transfecção , Resultado do Tratamento , Replicação Viral/efeitos dos fármacos , Replicação Viral/genética
5.
Cancer Lett ; 481: 1-14, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32268166

RESUMO

UBE2L3 is a ubiquitin-conjugating protein belonging to the E2 family that consists of 153 amino acid residues. In this study, we found that UBE2L3 was generally upregulated in clinical HCC samples compared to non-tumour samples and that there was a strong association between high UBE2L3 expression and tumour size, clinical grade and prognosis in HCC patients. UBE2L3 depletion inhibited the proliferation and induced the apoptosis of HCC cells. At the molecular level, we observed that UBE2L3 depletion enhanced the protein stability of GSK3ß, thus promoting the expression and activation of GSK3ß. Subsequently, activated GSK3ß phosphorylated p65 and promoted its nuclear translocation to increase the expression of target genes, including PUMA, Bax, Bim, Bad, and Bid. In vivo, knockout of UBE2L3 in HCC cells inhibited tumour growth in orthotopic liver injection nude mouse models. Moreover, inhibition of p65 or GSK3ß significantly restored the effects induced by UBE2L3 knockout in HCC. Together, this study reveals the stimulatory effect of UBE2L3 on HCC cell proliferation, suggesting that UBE2L3 may be an important pro-tumorigenic factor in liver carcinogenesis and a potential therapeutic target of HCC.


Assuntos
Apoptose/genética , Carcinoma Hepatocelular/genética , Glicogênio Sintase Quinase 3 beta/genética , Neoplasias Hepáticas/genética , Transdução de Sinais/genética , Fator de Transcrição RelA/genética , Enzimas de Conjugação de Ubiquitina/genética , Animais , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células/genética , Humanos , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Fosforilação/genética , Regulação para Cima/genética
6.
Cell Commun Signal ; 17(1): 168, 2019 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-31842909

RESUMO

BACKGROUND: Our previous study has demonstrated that NAD(P)H: quinone oxidoreductase 1 (NQO1) is significantly upregulated in human liver cancer where it potentiates the apoptosis evasion of liver cancer cell. However, the underlying mechanisms of the oncogenic function of NQO1 in HCC have not been fully elucidated. METHODS: Expression of NQO1, SIRT6, AKT and X-linked inhibitor of apoptosis protein (XIAP) protein were measured by western blotting and immunohistochemistry. Additionally, the interaction between NQO1 and potential proteins were determined by immunoprecipitation assays. Furthermore, the effect of NQO1 and SIRT6 on tumor growth was determined in cell model and orthotopic tumor implantation model. RESULTS: We found that NQO1 overexpression in HCC enhanced SIRT6 protein stability via inhibiting ubiquitin-mediated 26S proteasome degradation. High level of SIRT6 reduced acetylation of AKT which resulted in increased phosphorylation and activity of AKT. Activated AKT subsequently phosphorylated anti-apoptotic protein XIAP at Ser87 which determined its protein stability. Reintroduction of SIRT6 or AKT efficiently rescued NQO1 knock-out-mediated inhibition of growth and induction of apoptosis. In orthotopic mouse model, NQO1 knock-out inhibited tumor growth and induced apoptosis while this effect was effectively rescued by SIRT6 overexpression or MG132 treatment partially. CONCLUSIONS: Collectively, these results reveal an oncogenic function of NQO1 in sustaining HCC cell proliferation through SIRT6/AKT/XIAP signaling pathway.


Assuntos
Apoptose , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , NAD(P)H Desidrogenase (Quinona)/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Sirtuínas/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células , Humanos , Neoplasias Hepáticas/patologia , NAD(P)H Desidrogenase (Quinona)/deficiência , Fosforilação , Estabilidade Proteica , Transdução de Sinais , Regulação para Cima
7.
EBioMedicine ; 49: 232-246, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31680002

RESUMO

BACKGROUND: Hepatitis B surface antigen (HBsAg) is one of the important clinical indexes for hepatitis B virus (HBV) infection diagnosis and sustained seroconversion of HBsAg is an indicator for functional cure. However, the level of HBsAg could not be reduced by interferons and nucleoside analogs effectively. Therefore, identification of a new drug targeting HBsAg is urgently needed. METHODS: In this study, 6-AN was screened out from 1500 compounds due to its low cytotoxicity and high antiviral activity. The effect of 6-AN on HBV was examined in HepAD38, HepG2-NTCP and PHHs cells. In addition, the antivirus effect of 6-AN was also identified in mouse model. FINDINGS: 6-AN treatment resulted in a significant decrease of HBsAg and other viral markers both in vitro and in vivo. Furthermore, we found that 6-AN inhibited the activities of HBV SpI, SpII and core promoter by decreasing transcription factor PPARα, subsequently reduced HBV RNAs transcription and HBsAg production. INTERPRETATION: We have identified a novel small molecule to inhibit HBV core DNA, HBV RNAs, HBsAg production, as well as cccDNA to a minor degree both in vitro and in vivo. This study may shed light on the development of a novel class of anti-HBV agent.


Assuntos
6-Aminonicotinamida/farmacologia , Antígenos de Superfície da Hepatite B/metabolismo , Vírus da Hepatite B/fisiologia , Replicação Viral/efeitos dos fármacos , 6-Aminonicotinamida/química , Animais , Biomarcadores/sangue , Modelos Animais de Doenças , Células Hep G2 , Vírus da Hepatite B/efeitos dos fármacos , Vírus da Hepatite B/genética , Humanos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Modelos Biológicos , Regiões Promotoras Genéticas/genética , Transcrição Gênica/efeitos dos fármacos , Viremia/sangue
8.
Cancer Lett ; 451: 156-167, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30867140

RESUMO

NAD(P)H: quinone oxidoreductase 1 (NQO1) is an antioxidant enzyme which is associated with poor prognosis in human breast, colon, lung and liver cancers. However, the molecular mechanisms underlying the pro-tumorigenic function of NQO1 remains unclear. This study investigated the function of NQO1 in the context of hepatocellular carcinoma (HCC) development. We found that NQO1 was frequently up-regulated in human liver cancer, and its high expression level was correlated with the tumor stage and low survival rate of HCC patients. Loss-of-function of NQO1 inhibited growth in HCC cells with increased apoptosis in vitro, and suppressed orthotopic tumorigenicity in vivo. Mechanistically, high level of NQO1 in HCC cells enhanced protein stability of X-linked inhibitor of apoptosis protein (XIAP) by increasing its phosphorylation at Ser 87. Reintroduction of wile type XIAP and the phospho-mimic mutants XIAPS87D significantly reversed NQO1 knock-down/out induced growth inhibition and apoptosis. In mouse model with orthotopically implanted hepatocarcinoma, NQO1 suppression and NQO1 inhibitor suppressed tumor growth and induced apoptosis. NQO1 plays an important role in sustaining HCC cell proliferation and may thus act as a potential therapeutic target in HCC treatment.


Assuntos
Apoptose , Carcinoma Hepatocelular/enzimologia , Neoplasias Hepáticas/enzimologia , NAD(P)H Desidrogenase (Quinona)/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo , Animais , Carcinoma Hepatocelular/patologia , Linhagem Celular Transformada , Humanos , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , NAD(P)H Desidrogenase (Quinona)/genética , Fosforilação
9.
Cancer Lett ; 452: 90-102, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-30914208

RESUMO

Invasion and metastasis are the predominant causes of lethal outcomes in patients with hepatocellular carcinoma (HCC). However, the molecular mechanism underlying the invasive or metastatic process are still insufficiently understood. Here, we first integrated several public databases and identified a novel protein kinase, PDZ-binding kinase (PBK) that was frequently upregulated and correlated with poor prognosis in patients with HCC. Gain- or loss-of-function analysis revealed that PBK promoted migration and invasion of HCC cells both in vitro and in vivo. Mechanistically, PBK enhanced uPAR expression by activating its promoter activity. Chromatin immunoprecipitation (ChIP) assay showed that ETV4 directly bound to the core region of uPAR promoter while PBK could enhance the binding of ETV4 to uPAR promoter. In orthotopic mouse model, PBK knockdown markedly inhibited the lung metastasis of HCC cells, while this effect was significantly restored by uPAR overexpression. Finally, there was a positive correlation between PBK and uPAR, ETV4 and uPAR in HCC clinical samples. Collectively, these findings revealed that PBK acted as a crucial kinase by promoting invasion and migration via the ETV4-uPAR signaling pathway, and it therefore could be a promising diagnostic biomarker and therapeutic target for HCC metastasis.


Assuntos
Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Lectinas de Ligação a Manose/genética , Glicoproteínas de Membrana/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-ets/genética , Receptores de Superfície Celular/genética , Animais , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Feminino , Células Hep G2 , Humanos , Fígado/citologia , Fígado/patologia , Neoplasias Hepáticas/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Quinases de Proteína Quinase Ativadas por Mitógeno/biossíntese , Invasividade Neoplásica/genética , Metástase Neoplásica/genética , Prognóstico , Interferência de RNA , RNA Interferente Pequeno/genética , Transdução de Sinais/genética
10.
Hepatology ; 69(5): 1885-1902, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30614547

RESUMO

Hepatitis B virus (HBV) infection is a common infectious disease, in which nuclear covalently closed circular DNA (cccDNA) plays a key role in viral persistence, viral reactivation after treatment withdrawal, and drug resistance. A recent genome-wide association study has identified that the ubiquitin conjugating enzyme E2 L3 (UBE2L3) gene is associated with increased susceptibility to chronic HBV (CHB) infection in adults. However, the association between UBE2L3 and children with CHB and the underlying mechanism remain unclear. In this study, we performed two-stage case-control studies including adults and independent children in the Chinese Han population. The rs59391722 allele in the promoter of the UBE2L3 gene was significantly associated with HBV infection in both adults and children, and it increased the promoter activity of UBE2L3. Serum UBE2L3 protein levels were positively correlated with HBV viral load and hepatitis B e antigen (HBeAg) levels in children with CHB. In an HBV infection cell model, UBE2L3 knockdown significantly reduced total HBV RNAs, 3.5-kb RNA, as well as cccDNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and human primary hepatocytes. A mechanistic study found that UBE2L3 maintained cccDNA stability by inducing proteasome-dependent degradation of apolipoprotein B mRNA editing enzyme catalytic subunit 3A, which is responsible for the degradation of HBV cccDNA. Moreover, interferon-α (IFN-α) treatment markedly decreased UBE2L3 expression, while UBE2L3 silencing reinforced the antiviral activity of IFN-α on HBV RNAs, cccDNA, and DNA. rs59391722 in UBE2L3 was correlated with HBV DNA suppression and HBeAg loss in response to IFN-α treatment of children with CHB. Conclusion: These findings highlight a host gene, UBE2L3, contributing to the susceptibility to persistent HBV infection; UBE2L3 may be involved in IFN-mediated viral suppression and serve as a potential target in the prevention and treatment of HBV infection.


Assuntos
Citidina Desaminase/metabolismo , Hepatite B Crônica/genética , Enzimas de Conjugação de Ubiquitina/genética , Desaminases APOBEC , Adulto , Estudos de Casos e Controles , Criança , Pré-Escolar , DNA Circular , Predisposição Genética para Doença , Células Hep G2 , Hepatite B Crônica/tratamento farmacológico , Humanos , Lactente , Interferon-alfa/uso terapêutico , Polimorfismo de Nucleotídeo Único , Enzimas de Conjugação de Ubiquitina/metabolismo , Replicação Viral
11.
Hepatology ; 68(4): 1260-1276, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29624717

RESUMO

Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA), which serves as a template for HBV RNA transcription, is responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified silent mating type information regulation 2 homolog 3 (SIRT3) as a host factor restricting HBV transcription and replication by screening seven members of the sirtuin family, which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5-kb RNA, as well as replicative intermediate DNA in HBV-infected HepG2-Na+ /taurocholate cotransporting polypeptide cells and primary human hepatocytes. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. A mechanistic study found that nuclear SIRT3 was recruited to the HBV cccDNA, where it deacetylated histone 3 lysine 9. Importantly, occupancy of SIRT3 on cccDNA could increase the recruitment of histone methyltransferase suppressor of variegation 3-9 homolog 1 to cccDNA and decrease recruitment of SET domain containing 1A, leading to a marked increase of trimethyl-histone H3 (Lys9) and a decrease of trimethyl-histone H3 (Lys4) on cccDNA. Moreover, SIRT3-mediated HBV cccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor Yin Yang 1 to cccDNA. Finally, hepatitis B viral X protein could relieve SIRT3-mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. CONCLUSION: SIRT3 is a host factor epigenetically restricting HBV cccDNA transcription by acting cooperatively with histone methyltransferase; these data provide a rationale for the use of SIRT3 activators in the prevention or treatment of HBV infection. (Hepatology 2018).


Assuntos
DNA Viral/genética , Epigênese Genética/genética , Hepatite B/genética , Domínios PR-SET/genética , Sirtuína 3/genética , Replicação Viral/genética , DNA Complementar/genética , Hepatite B/fisiopatologia , Vírus da Hepatite B/genética , Histona Metiltransferases/metabolismo , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sensibilidade e Especificidade
12.
Biochem Biophys Res Commun ; 485(4): 713-719, 2017 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-28238784

RESUMO

SIRT6 is a class III histone deacetylase that has been implicated in HCC development. We previously reported that SIRT6 potentiated apoptosis evasion in hepatocellular carcinoma by inhibiting both Bax expression and mitochondrial translocalization. However, the mechanism underlying SIRT6-mediated inhibition of Bax mitochondrial localization remains elusive. In this study, we found that although SIRT6 had no effect on the expression level of Ku70, SIRT6 could interact with Ku70 and deacetylate it. The increased acetylation of Ku70 in SIRT6-depleted cells disrupt its interaction with Bax, which finally resulted in Bax mitochondrial translocalization. Furthermore, lysine K542 on Ku70 was the target for deacetylation by SIRT6. Ku70K542Q mutation abolished suppression of association between Ku70 and Bax and caused redistribution of Bax to the cytosol in SIRT6-depleted cells. Finally, Ku70K542Q mutation could reversed the inhibition of growth and apoptosis promotion mediated by SIRT6 silencing. Together, our findings revealed SIRT6 could block the mitochondrial translocation of Bax and decrease the apoptotic ratio of HCC cells by deacetylation of Ku70. SIRT6 may serve as a promising target for developing targeted therapies for HCC in the future.


Assuntos
Apoptose , Autoantígeno Ku/metabolismo , Sirtuínas/metabolismo , Proteína X Associada a bcl-2/metabolismo , Acetilação , Western Blotting , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Expressão Gênica , Humanos , Autoantígeno Ku/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Lisina/genética , Lisina/metabolismo , Microscopia de Fluorescência , Mitocôndrias/metabolismo , Mutação , Ligação Proteica , Transporte Proteico/genética , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sirtuínas/genética , Proteína X Associada a bcl-2/genética
13.
Oncotarget ; 7(31): 50117-50130, 2016 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-27367026

RESUMO

SIRT3, a class III histone deacetylase, has been implicated in various cancers as a novel therapeutic target. In hepatocellular carcinoma (HCC), we previously reported that SIRT3 induced cell apoptosis by regulating GSK-3ß/Bax signaling pathway. Downregulation of SIRT3 in HCC cells facilitates tumor cell survival. In this study, we found that chemotherapeutic agents (doxorubicin, cisplatin and epirubicin) and sorafenib treatment downregulated SIRT3 mRNA and protein levels in three HCC cell lines. MTS assay found that SIRT3 overexpression sensitized liver cancer cells to chemotherapeutic agents and sorafenib in SMMC-7721, Huh-7 and PLC/PRF/5 cell lines. Moreover, SIRT3 overexpression promoted chemotherapeutic agents-induced or sorafenib-induced apoptosis as evidenced by flow cytometry, enhanced PARP cleavage and enhanced Caspase-9 cleavage in three HCC cells. In contrast, SIRT3 silencing increased drug resistance of HCC cells to chemotherapeutic agents. Mechanistic study found that SIRT3 downregulated the mRNA and protein levels of glutathione S-transferase pi 1 (GSTP1), which is a member of phase II detoxification enzymes families involved in metabolizing for chemotherapeutic agents. Moreover, SIRT3 decreased the amount of GSTP1 that was associated with JNK, which finally contributed the activation of JNK activity and activation of downstream target c-Jun and Bim. Importantly, GSTP1 overexpression or JNK inhibitor abolished SIRT3-induced apoptosis in HCC cells exposed to chemotherapeutic agents. Finally, there was a negative correlation between SIRT3 expression and GSTP1 expression in human HCC tissues. Together, our findings revealed SIRT3 could enhance the drug sensitivity of HCC cells to an array of chemotherapeutic agents. SIRT3 may serve as a potential target for improving the chemosensitivity of HCC patients.


Assuntos
Carcinoma Hepatocelular/metabolismo , Glutationa S-Transferase pi/metabolismo , Neoplasias Hepáticas/metabolismo , MAP Quinase Quinase 4/metabolismo , Sirtuína 3/metabolismo , Antineoplásicos/farmacologia , Apoptose , Carcinoma Hepatocelular/tratamento farmacológico , Linhagem Celular Tumoral , Separação Celular , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Glutationa , Quinase 3 da Glicogênio Sintase/metabolismo , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Compostos de Fenilureia/farmacologia , RNA Mensageiro/metabolismo , Transdução de Sinais , Sorafenibe
14.
PLoS One ; 11(3): e0150961, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26950437

RESUMO

BACKGROUND/AIM: The hepatitis B virus (HBV) infection is accompanied by the induction of oxidative stress, especially mediated by HBV X protein (HBx). Oxidative stress has been implicated in a series of pathological states, such as DNA damage, cell survival and apoptosis. However, the host factor by which cells protect themselves under this oxidative stress is poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we first confirmed that HBV infection significantly induced oxidative stress. Moreover, viral protein HBx plays a major role in the oxidative stress induced by HBV. Importantly, we found that mitochondrial protein SIRT3 overexpression could decrease reactive oxygen species (ROS) induced by HBx while SIRT3 knockdown increased HBx-induced ROS. Importantly, SIRT3 overexpression abolished oxidative damage of HBx-expressing cells as evidenced by γH2AX and AP sites measurements. In contrast, SIRT3 knockdown promoted HBx-induced oxidative damage. In addition, we also observed that oxidant H2O2 markedly promoted HBV replication while the antioxidant N-acetyl-L-cysteine (NAC) inhibited HBV replication. Significantly, SIRT3 overexpression inhibited HBV replication by reducing cellular ROS level. CONCLUSIONS/SIGNIFICANCE: Collectively, these data suggest HBx expression induces oxidative stress, which promotes cellular oxidative damage and viral replication during HBV pathogenesis. Mitochondrial protein SIRT3 protected HBx expressing-cells from oxidative damage and inhibited HBV replication possibly by decreased cellular ROS level. These studies shed new light on the physiological significance of SIRT3 on HBx-induced oxidative stress, which can contribute to the liver pathogenesis.


Assuntos
Estresse Oxidativo , Sirtuína 3/metabolismo , Transativadores/genética , Linhagem Celular , Expressão Gênica , Vírus da Hepatite B/metabolismo , Vírus da Hepatite B/fisiologia , Humanos , Fígado/citologia , Fígado/metabolismo , Fígado/virologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas Virais Reguladoras e Acessórias , Replicação Viral
15.
Arch Virol ; 161(3): 621-30, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26660162

RESUMO

We previously reported that SIRT1, an NAD(+)-dependent deacetylase belonging to the class III histone deacetylases, enhances hepatitis virus B (HBV) replication by targeting the transcription factor AP-1. However, the potential antiviral effects of nicotinamide, a SIRT1 inhibitor, have not yet been explored. In this study, we show that nicotinamide exhibits potent anti-HBV activity with little cytotoxicity. Nicotinamide suppressed both HBV DNA replicative intermediates and 3.5-kb mRNA expression. Moreover, nicotinamide treatment also suppressed core protein expression and the secretion of the hepatitis B surface antigen (HBsAg) and the hepatitis B e antigen (HBeAg) in HBV-expressing cell models. Importantly, nicotinamide treatment suppressed serum HBV DNA, HBsAg and HBeAg levels and liver HBV DNA in HBV-transgenic mice. Furthermore, using a dual-luciferase reporter assay, it was found that nicotinamide exhibited a marked inhibitory effect on the HBV core, SpI, SpII and X promoters, accompanied by decreased expression of the transcription factors AP-1, C/EBPα and PPARα. Therefore, nicotinamide suppresses HBV replication in vitro and in vivo by diminishing HBV promoter activity. This study highlights the potential application of nicotinamide in HBV therapy.


Assuntos
Antivirais/administração & dosagem , Antivirais/farmacologia , Vírus da Hepatite B/efeitos dos fármacos , Niacinamida/administração & dosagem , Niacinamida/farmacologia , Sirtuína 1/antagonistas & inibidores , Replicação Viral/efeitos dos fármacos , Animais , Antivirais/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Vírus da Hepatite B/fisiologia , Hepatócitos/efeitos dos fármacos , Hepatócitos/virologia , Humanos , Camundongos Transgênicos , Niacinamida/toxicidade
16.
J Gastrointest Cancer ; 41(4): 243-7, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20431961

RESUMO

BACKGROUND: To investigate the early diagnosis and outcomes of surgical treatment of primary duodenal adenocarcinoma (PDAC) for curative purpose. METHOD: Thirty-two PDAC patients treated surgically between February 1990 and September 2006 were analyzed retrospectively. RESULTS: All 32 patients underwent laparotomy including 18 (56.3%) pancreaticoduodenectomy (PD), six (18.7%) segmental resection (SR), and eight bypass procedures. And R0 resections were obtained in 22 patients; the other ten procedures were palliative. The total 1-, 3-, and 5-year survival rates in this study were 78.1% (25/32), 43.8% (14/32), and 18.8% (6/32), respectively; moreover, the 1-, 3-, and 5-year survival rates in patients with R0 resection were 100.0% (20/20), 70.0% (14/20), and 30.0% (6/20), which were significantly higher than those (41.7% = /12, 0%, and 0%) in patients with palliative operation (P < 0.05), respectively. Furthermore, the 5-year survival rate was 27.8% (5/18) in pancreaticoduodenectomy patients and 16.7% (1/6) in segmental resection patients, and there was no significant difference between the above two procedures (P > 0.05). CONCLUSION: PD is suggested for tumor located at the first and second portion of the duodenum, and SR may be appropriate for the selected patients especially for tumors of the distal duodenum.


Assuntos
Adenocarcinoma/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório , Neoplasias Duodenais/cirurgia , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Adulto , Idoso , Procedimentos Cirúrgicos do Sistema Digestório/métodos , Neoplasias Duodenais/mortalidade , Neoplasias Duodenais/patologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , Resultado do Tratamento
17.
World J Gastroenterol ; 16(12): 1527-32, 2010 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-20333796

RESUMO

AIM: To evaluate the clinical presentation, treatment and survival of patients with primary malignant tumor of small bowel (PMTSB). METHODS: Clinicopathologic data about 141 surgically treated PMTSB patients (91 males and 50 females) at the median age of 53.5 years (range 23-79 years) were retrospectively analyzed. RESULTS: The most common initial clinical features of the patients were intermittent abdominal discomfort or vague abdominal pain (67.4%), abdominal mass (31.2%), bowel obstruction (24.1%), hemotochezia (21.3%), jaundice (16.3%), fever (14.2%), coexistence of bowel perforation and peritonitis (5.7%), coexistence of gastrointestinal bleeding and shock (5.0%), and intraabdominal bleeding (1.4%). Ileum was the most common site of tumor (44.7%), followed by jejunum (30.5%) and duodenum (24.8%). PMTSB had a nonspecific clinical presentation. Segmental bowel resection (n = 81) was the most common surgical procedure, followed by right hemi-colectomy (n = 15), pancreaticoduodenectomy (n = 10), and others (n = 19). Twenty-seven adenocarcinoma patients and 13 malignant lymphoma patients received adjuvant chemotherapy with 5-fluorouracil and cyclophosphamide, adriamycin, vincristine and prednisone, respectively. Information about 120 patients was obtained during the follow-up. The median survival time of PMTSB patients was 20.3 mo. The 1-, 3- and 5-year survival rate was 75.0% (90/120), 40.0% (48/120) and 20.8% (25/120), respectively. Adenocarcinoma was found in 73.7% (42/57), 21.1% (12/57) and 15.8% (9/57) of the patients, respectively. Gastrointestinal stromal tumor was observed in 80.0% (20/25), 72.0% (18/25) and 36.0% (9/25) of the patients, respectively. Carcinoid was detected in 100.0% (15/15), 80.0% (12/15) and 46.7% (7/15) of the patients, respectively. Malignant lymphoma was demonstrated in 69.2% (9/13), 30.8% (4/13) and 0% (0/13) of the patients, respectively. CONCLUSION: En bloc resection is the principal therapy for most PMTSB and chemotherapy is the important treatment modality for malignant lymphoma and other malignant tumors of small bowel which cannot be radically removed.


Assuntos
Adenocarcinoma/cirurgia , Tumor Carcinoide/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório , Tumores do Estroma Gastrointestinal/cirurgia , Neoplasias Intestinais/cirurgia , Intestino Delgado/cirurgia , Linfoma/cirurgia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/mortalidade , Adenocarcinoma/secundário , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Tumor Carcinoide/tratamento farmacológico , Tumor Carcinoide/mortalidade , Tumor Carcinoide/secundário , Quimioterapia Adjuvante , Feminino , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Tumores do Estroma Gastrointestinal/mortalidade , Tumores do Estroma Gastrointestinal/secundário , Humanos , Neoplasias Intestinais/tratamento farmacológico , Neoplasias Intestinais/mortalidade , Neoplasias Intestinais/patologia , Intestino Delgado/patologia , Estimativa de Kaplan-Meier , Linfoma/tratamento farmacológico , Linfoma/mortalidade , Linfoma/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Medição de Risco , Fatores de Tempo , Resultado do Tratamento , Adulto Jovem
18.
J Gastrointest Cancer ; 40(1-2): 33-7, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19513860

RESUMO

BACKGROUND: The purpose of this study was to investigate the early diagnosis and outcomes of surgical treatment of primary duodenal adenocarcinoma (PDAC) for curative purpose. METHOD: Thirty-two PDAC patients treated surgically between February 1990 and September 2006 were analyzed retrospectively. RESULTS: All 32 patients underwent laparotomy, including 18 patients (56.3%) pancreaticoduodenectomy (PD), six patients (18.7%) segmental resection (SR), and eight patients bypass procedures. R0 resections were obtained in 22 patients; the other 10 procedures were palliative. The total 1-, 3-, and 5-year survival rates in this study were 86.2% (25/29), 48.3% (14/29), and 20.7% (6/29), respectively, moreover, the 1-, 3-, and 5-year survival rates in patients with R0 resection were 100.0% (19/19), 73.7% (14/19), and 31.6%(6/19), which were significantly higher than those (50.0% = 5/10, 0%, and 0%) in patients with palliative operation (P > 0.05), respectively. Furthermore, the 5-year survival rate was 27.8% (5/18) in pancreaticoduodenectomy patients and 16.7% (1/6) in segmental resection patients, and there was no significant difference between the above two procedures (P > 0.05). CONCLUSION: PD is suggested for tumor located at the first and second portion of the duodenum, and SR may be appropriate for the selected patients, especially for tumors of the distal duodenum.


Assuntos
Adenocarcinoma/mortalidade , Adenocarcinoma/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório/métodos , Neoplasias Duodenais/mortalidade , Neoplasias Duodenais/cirurgia , Adenocarcinoma/patologia , Adulto , Idoso , Neoplasias Duodenais/patologia , Feminino , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , Resultado do Tratamento
19.
Asian J Surg ; 32(1): 1-6, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19321395

RESUMO

Liver malignancy is known to be associated with hepatolithiasis. The present report summarises the results and our experience for management of 23 patients with intrahepatic hepatolithiasis associated cholangiocarcinoma (IHHCC). The correct diagnosis rates of US (ultrasonography), CT (computed tomography), and MRCP (magnetic resonance cholangiopancreatography) were 82.6% (19/23), 95.7% (22/23), and 91.7% (11/12), respectively. Carbohydrate antigen 19-9 (CA 19-9) was helpful in the diagnosis of IHHCC. All 23 patients with IHHCC underwent laparotomy. The surgical procedure consisted hepatectomy with a bile duct exploration in 16 patients (69.6%), a hepatectomy and drainage procedure such as sphincteroplasty and choledo-jejunostomy in three patients (13.0%), a bile duct exploration with biopsy in two patients (8.7%), and simple laparotomy and biopsy in two patients (8.7%). All the IHHCC patients who underwent a palliative procedure or laparotomy died within 1 year, and the overall cumulative survival rates at 1, 3, and 5 years were 43.8% (10/23), 13.0% (3/23), and 4.3% (1/23), respectively, and those patients who underwent curative resection were 88.9% (8/9), 33.3% (3/9), and 11.1% (1/9), respectively, which significantly longer than those (20.0%, 2/10; 0.0%, 0/10; and 0.0%, 0/10) patients who underwent palliative resection, respectively (p < 0.05). A suspicion of malignancy is necessary when managing patients with long-term hepatolithiasis. Hepatic resection with postoperative treatment is the treatment of choice for cholangiocarcinoma when it is resectable.


Assuntos
Neoplasias dos Ductos Biliares/diagnóstico , Neoplasias dos Ductos Biliares/cirurgia , Ductos Biliares Intra-Hepáticos , Colangiocarcinoma/diagnóstico , Colangiocarcinoma/cirurgia , Litíase/patologia , Adulto , Idoso , Neoplasias dos Ductos Biliares/etiologia , China , Colangiocarcinoma/etiologia , Estudos de Coortes , Feminino , Hepatectomia , Humanos , Litíase/cirurgia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
20.
Hepatobiliary Pancreat Dis Int ; 7(6): 638-42, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19073411

RESUMO

BACKGROUND: Some patients with chronic pancreatitis (CP) may require surgery mainly because of intractable pain, suspicion of malignancy, or complications related to CP. This study aimed to analyze the efficacy of surgical treatment for patients with CP in terms of pain relief, control of local complications, and pancreatic endocrine/exocrine function. METHODS: Twenty-six patients with CP were treated surgically at our hospital from June 1985 to November 2005. The clinical data of these patients were analyzed retrospectively. RESULTS: The follow-up time ranged from 8 to 130 months with a median of 60.6 months. No patients were lost to follow-up. All patients had improvement of clinical symptoms such as abdominal pain, steatorrhea and weight loss, to some degree, especially pain relief in patients with good dilation and high pressure of the main pancreatic duct. The endocrine and exocrine functions were not alleviated in all patients, otherwise the impaired glucose tolerance was improved in 8 (30.8%), 15 (57.7%) maintained the same body weight, one (3.8%) had an acute attack of CP, and 2 (7.7%) developed pancreatic carcinoma in the 16th and 28th month postoperatively and died within 3 years after operation for CP. The 1-, 3-, 5-year pain-free rates of CP patients were 96.2% (25/26), 88.5% (23/26) and 84.6% (22/26), respectively. CONCLUSIONS: In selected patients with CP, surgical treatment is a safe procedure and can effectively relieve pain and control local complications; also, it is helpful to improve the quality of life for patients with pancreatitis, and to control the development of this disease.


Assuntos
Pancreaticoduodenectomia/mortalidade , Pancreaticojejunostomia/mortalidade , Pancreatite Crônica/mortalidade , Pancreatite Crônica/cirurgia , Complicações Pós-Operatórias/mortalidade , Adulto , Idoso , Feminino , Seguimentos , Humanos , Ilhotas Pancreáticas/fisiologia , Masculino , Pessoa de Meia-Idade , Morbidade , Dor/mortalidade , Dor/cirurgia , Pâncreas Exócrino/fisiologia , Neoplasias Pancreáticas/mortalidade , Estudos Retrospectivos
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