Hepatitis B virus X protein induces apoptosis and cell cycle deregulation throug

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Hepatology Research (OnlineEarly Articles).

doi:10.1111/j.1872-034X.2007.00213.x

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Abstract

Original Article

Hepatitis B virus X protein induces apoptosis and cell cycle deregulation

through interfering with DNA repair and checkpoint responses

Hong-Ying Chen,1Departments of 1Gastroenterology and Nan-Hong

Tang,22Hepatobiliary Surgery, Union Hospital, Fuzhou, China Na

Lin,1Departments of 1Gastroenterology and Zhi-Xin Chen1Departments of

1Gastroenterology and and Xiao-Zhong Wang1Departments of 1Gastroenterology

and Dr Xiao-Zhong Wang, Department of Gastroenterology, Union Hospital of

Fujian Medical University, Fuzhou, China. Email: drwangxz@...

Departments of 1Gastroenterology and 2Hepatobiliary Surgery, Union Hospital,

Fuzhou, China

Dr Xiao-Zhong Wang, Department of Gastroenterology, Union Hospital of Fujian

Medical University, Fuzhou, China. Email: drwangxz@...

Abstract

Aim: To investigate the effects of hepatitis B virus X (HBx) gene on

apoptosis and cell cycle in hepatocyte line HL-7702 and to discuss the

possible mechanisms in the pathway.

Methods: The recombinant plasmid pcDNA3-X and vector pcDNA3 were transfected

into HL-7702 cells and selected by G418 to construct two new cell lines,

which were named HL-7702-HBx and HL-7702-con, respectively. Reverse

transcription polymerase chain reaction (RT–PCR) and western blot analysis

were used to confirm that HBx gene was expressed steadily in the HL-7702-HBx

cells. Then apoptosis and cell cycle of the two cells were detected by DNA

ladder, flow cytometric analysis, and electronic microscope observation.

Apoptosis and cell cycle gene expressions in the two cells were subsequently

evaluated by using gene arrays. Some of results were further confirmed by

real-time PCR and western blot analysis.

Results: RT–PCR and the western blot analysis showed that HL-7702-HBx

expressed the HBx gene steadily. Comparedwith the HL-7702-con cells, there

was increased apoptosis and accumulation of the S phase in the HL-7702-HBx

cells. The gene array analysis indicated that some DNA repair genes (XRCC1,

DDB1, etc.) and DNA damage checkpoint-related genes (Cdc47, RAD17, etc.)

played roles in the HBx-mediated imbalance of apoptosis and cell cycle. Both

cDNA array analysis and real-time RT–PCR showed that mRNA of XRCC1, Cdc47

and RAD17 were upregulated by HBx. Unexpectedly, the western blot analysis

revealed that HBx inhibited their protein expression.

Conclusion: The expression of HBx in HL-7702 cells promoted apoptosis and

accumulation of the S phase through the inhibition of DNA repair and

checkpoints via post-transcriptional mechanisms.

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1872-034X.2007.00213.x

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[Guest guest]

Hepatology Research (OnlineEarly Articles).

doi:10.1111/j.1872-034X.2007.00213.x

Prev Article Next Article

Abstract

Original Article

Hepatitis B virus X protein induces apoptosis and cell cycle deregulation

through interfering with DNA repair and checkpoint responses

Hong-Ying Chen,1Departments of 1Gastroenterology and Nan-Hong

Tang,22Hepatobiliary Surgery, Union Hospital, Fuzhou, China Na

Lin,1Departments of 1Gastroenterology and Zhi-Xin Chen1Departments of

1Gastroenterology and and Xiao-Zhong Wang1Departments of 1Gastroenterology

and Dr Xiao-Zhong Wang, Department of Gastroenterology, Union Hospital of

Fujian Medical University, Fuzhou, China. Email: drwangxz@...

Departments of 1Gastroenterology and 2Hepatobiliary Surgery, Union Hospital,

Fuzhou, China

Dr Xiao-Zhong Wang, Department of Gastroenterology, Union Hospital of Fujian

Medical University, Fuzhou, China. Email: drwangxz@...

Abstract

Aim: To investigate the effects of hepatitis B virus X (HBx) gene on

apoptosis and cell cycle in hepatocyte line HL-7702 and to discuss the

possible mechanisms in the pathway.

Methods: The recombinant plasmid pcDNA3-X and vector pcDNA3 were transfected

into HL-7702 cells and selected by G418 to construct two new cell lines,

which were named HL-7702-HBx and HL-7702-con, respectively. Reverse

transcription polymerase chain reaction (RT–PCR) and western blot analysis

were used to confirm that HBx gene was expressed steadily in the HL-7702-HBx

cells. Then apoptosis and cell cycle of the two cells were detected by DNA

ladder, flow cytometric analysis, and electronic microscope observation.

Apoptosis and cell cycle gene expressions in the two cells were subsequently

evaluated by using gene arrays. Some of results were further confirmed by

real-time PCR and western blot analysis.

Results: RT–PCR and the western blot analysis showed that HL-7702-HBx

expressed the HBx gene steadily. Comparedwith the HL-7702-con cells, there

was increased apoptosis and accumulation of the S phase in the HL-7702-HBx

cells. The gene array analysis indicated that some DNA repair genes (XRCC1,

DDB1, etc.) and DNA damage checkpoint-related genes (Cdc47, RAD17, etc.)

played roles in the HBx-mediated imbalance of apoptosis and cell cycle. Both

cDNA array analysis and real-time RT–PCR showed that mRNA of XRCC1, Cdc47

and RAD17 were upregulated by HBx. Unexpectedly, the western blot analysis

revealed that HBx inhibited their protein expression.

Conclusion: The expression of HBx in HL-7702 cells promoted apoptosis and

accumulation of the S phase through the inhibition of DNA repair and

checkpoints via post-transcriptional mechanisms.

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1872-034X.2007.00213.x

_________________________________________________________________

Puzzles, trivia teasers, word scrambles and more. Play for your chance to

win! http://club.live.com/home.aspx?icid=CLUB_hotmailtextlink