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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2003-8-19
pubmed:abstractText
Treatment of hepatocellular carcinoma (HCC) cells with butyrate can induce apoptosis irrespective of hepatitis B virus integration. No information is available, however, regarding the effect of butyrate on HCC in the presence of hepatitis C virus (HCV) because some HCV proteins can regulate cell survival. By gene transfer, we found that HCV core enhances but HCV NS5A antagonizes sodium phenylbutyrate (NaPB)-induced apoptosis in HCC cells, which is independent of p53. We then chose the p53-negative Hep3B HCC cell to investigate the mechanism of anti-apoptosis mediated by NS5A. In the NaPB-treated Hep3B cells without NS5A expression, induction of apoptosis was associated with Bax redistribution from the cytosol to the nucleus interior and subsequently, to a nuclear membrane-bound form. In the NS5A expressing Hep3B cells, NaPB treatment also triggered relocalization of both Bax and NS5A from the cytosol to the nucleus interior but Bax retained inside the nucleus and did not finally move to the nuclear membrane. Using double immunofluorescence and coimmunoprecipitation, we demonstrated that NS5A co-localizes and interacts with Bax in the nucleus. The HCV NS5A protein was further found to contain Bcl-2 homology domains (BH3, BH1 and BH2). Additional studies using deleted NS5A constructs were carried out to determine whether the BH2 domain or nuclear localization signal (NLS) in NS5A is required for interaction with Bax in the nucleus or inhibition of apoptosis. NS5A with deletion of both BH2 domain and NLS localized in the cytoplasm, dissociated with Bax, and lost anti-apoptosis activity during NaPB treatment. In contrast, NS5A with intact BH domains except NLS still bound directly to Bax in the perinuclear region or the nucleus, but showed less association with Bax in the nucleus and lower effect in apoptosis inhibition than full-length NS5A. These results suggest that HCV NS5A as a Bcl-2 homologue interacts with Bax to protect p53-negative HCC cells from NaPB-induced apoptosis.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/BAX protein, human, http://linkedlifedata.com/resource/pubmed/chemical/DNA, Viral, http://linkedlifedata.com/resource/pubmed/chemical/NS-5 protein, hepatitis C virus, http://linkedlifedata.com/resource/pubmed/chemical/Nuclear Localization Signals, http://linkedlifedata.com/resource/pubmed/chemical/Phenylbutyrates, http://linkedlifedata.com/resource/pubmed/chemical/Proto-Oncogene Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Proto-Oncogene Proteins c-bcl-2, http://linkedlifedata.com/resource/pubmed/chemical/RNA Replicase, http://linkedlifedata.com/resource/pubmed/chemical/Tumor Suppressor Protein p53, http://linkedlifedata.com/resource/pubmed/chemical/Viral Nonstructural Proteins, http://linkedlifedata.com/resource/pubmed/chemical/bcl-2-Associated X Protein
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0020-7136
pubmed:author
pubmed:copyrightInfo
Copyright 2003 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:day
20
pubmed:volume
107
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
65-73
pubmed:dateRevised
2007-7-24
pubmed:meshHeading
pubmed-meshheading:12925958-Apoptosis, pubmed-meshheading:12925958-Blotting, Western, pubmed-meshheading:12925958-Carcinoma, Hepatocellular, pubmed-meshheading:12925958-Cell Nucleus, pubmed-meshheading:12925958-DNA, Viral, pubmed-meshheading:12925958-Fluorescent Antibody Technique, pubmed-meshheading:12925958-Hepatitis C, pubmed-meshheading:12925958-Humans, pubmed-meshheading:12925958-Immunoenzyme Techniques, pubmed-meshheading:12925958-Liver Neoplasms, pubmed-meshheading:12925958-Nuclear Localization Signals, pubmed-meshheading:12925958-Phenylbutyrates, pubmed-meshheading:12925958-Precipitin Tests, pubmed-meshheading:12925958-Proto-Oncogene Proteins, pubmed-meshheading:12925958-Proto-Oncogene Proteins c-bcl-2, pubmed-meshheading:12925958-RNA Replicase, pubmed-meshheading:12925958-Transfection, pubmed-meshheading:12925958-Tumor Cells, Cultured, pubmed-meshheading:12925958-Tumor Suppressor Protein p53, pubmed-meshheading:12925958-Up-Regulation, pubmed-meshheading:12925958-Viral Nonstructural Proteins, pubmed-meshheading:12925958-bcl-2-Associated X Protein
pubmed:year
2003
pubmed:articleTitle
Hepatitis C virus NS5A as a potential viral Bcl-2 homologue interacts with Bax and inhibits apoptosis in hepatocellular carcinoma.
pubmed:affiliation
Department of Radiation Oncology, Koo Foundation Sun Yat-Sen Cancer Center, Taipei, Taiwan, Republic of China. ylchung@mail.kfcc.org.tw
pubmed:publicationType
Journal Article