Hepatitis B viral X protein alters the biological features and expressions of DNA repair enzymes in LO2 cells.
OBJECTIVE
This study aimed at examining the effects of hepatitis B viral X protein (HBx) on the biological features and the expression of DNA repair enzymes in non-tumour human hepatic LO2 cells in vitro.


METHODS
The HBx gene was transfected into LO2 cells to establish stably HBx-expressing LO2/HBx cells. The morphological features, cell growth, cell cycle, apoptosis and colony formation of LO2/HBx cells, vector-transfected LO2/pcDNA3.1 cells and unmanipulated LO2 cells were studied. The expressions of DNA repair enzymes and DNA oxidative stress-related 8-hydroxydeoxyguanosine (8-OHdG) were determined by a real-time quantitative polymerase chain reaction assay and high-performance liquid chromatography coupled with electrochemical detection respectively.


RESULTS
In comparison with controls, significant morphological changes, faster growth, higher frequency of cells at the S phase, but lower at G0/G1 and M/G2 phases, a lower frequency of natural cell apoptosis and a higher percentage of colony formation were observed in the LO2/HBx cells. Furthermore, significantly higher levels of intracellular 8-OHdG and lower levels of human DNA glycosylase alpha (hMYHalpha) mRNA transcripts, but no significant change in human 8-oxoguanine DNA glycosylase 1 (hOGG1), were detected in the LO2/HBx cells.


CONCLUSIONS
Our data indicated that HBx promoted growth and malignant transformation of non-tumour hepatic LO2 cells in vitro, which was associated with the downregulation of hMYHalpha expression and accumulation of mutagenic DNA adduct 8-OHdG.
Cheng
Bin
B
Department of Gastroenterology and Hepatology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. b.cheng@tjh.tjmu.edu.cn
Zheng
Yaochu
Y
Guo
Xiaorong
X
Wang
Ying
Y
Liu
Chunyan
C
D000080242:8-Hydroxy-2'-Deoxyguanosine; D017209:Apoptosis / Q000235:genetics; D002453:Cell Cycle / Q000235:genetics; D002460:Cell Line; D002470:Cell Survival / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D003114:Colony-Forming Units Assay; D045647:DNA Glycosylases / Q000235:genetics* / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D015536:Down-Regulation; D005562:Formazans; D006509:Hepatitis B; D006515:Hepatitis B virus / Q000235:genetics; D022781:Hepatocytes / Q000201:enzymology*; D006801:Humans; D018384:Oxidative Stress / Q000235:genetics; D013778:Tetrazolium Salts; D015534:Trans-Activators / Q000502:physiology*; D054334:Viral Regulatory and Accessory Proteins
D005562:Formazans; D013778:Tetrazolium Salts; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; C079782:MTT formazan; D000080242:8-Hydroxy-2'-Deoxyguanosine; D045647:DNA Glycosylases; D003849:Deoxyguanosine