[Hepatitis B virus and deletion of its COOH-terminal forty amino acids: proliferative impact on hepatoma cell line SMMC-7721].
OBJECTIVE
To explore the biological impact of 40 amino acid deletion at the C-terminal of hepatitis B virus X on the proliferation of hepatoma cells.


METHODS
Cells of SMMC-7721 hepatoma cell line were transfected with HBx and its derivative HBx3'-40, harboring the 40 amino acid deletion at the distal C-terminal region. Cell growth curve, colony formation in soft agar plate and tumorigenesis assay in nude mice were used to observe the alterations induced by the transfection of HBx and HBx3'-40. The expression level of PCNA in tumor cells was also investigated.


RESULTS
The growth rates of the cells transfected with HBx and HBx3'-40 were markedly increased as compared with that of the control group. The colony formation rates were enhanced in the cells transfected with HBx(48.7 +/- 8.1) and HBx3'-40 (82.8+/-6.0), comparing with the control (26.9 +/- 3.5) %. In the tumorigenic assay, the size and weight of tumors were significantly increased in the cells transfected with HBx (0.412 +/- 0.212, 0.395 +/- 0.159) % and HBx3'-40 (1.476 +/- 0.232, 0.987 +/- 0.279) %, as compared with the control group (0.051 +/- 0.024, 0.033 +/-0.004) %. The expression level of PCNA in tumors was increased in both HBx (59.00 +/- 2.58) % and HBx3'-40 (69.25 +/- 3.77) % transfected cells, comparing with the control (37.67 +/- 2.52) %. Overall, the cells transfected with HBx3'-40 demonstrated the highest proliferative capacity.


CONCLUSIONS
The deletion of 40 amino acids in the C-terminal of HBx is correlated with an enhanced proliferation of hepatoma cells and may play an important role in the malignant transformation of the liver.
Lin
Jing
J
Hepatitis B virus X and deletion of its COOH-terminal forty amino acids: proliferative impact on hepatoma cell line SMMC-7721.
Zhu
Ming-hua
MH
Qu
Jian-hui
JH
Ni
Can-rong
CR
Li
Fang-mei
FM
D000595:Amino Acid Sequence; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006515:Hepatitis B virus / Q000235:genetics; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics*; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins
D018809:Proliferating Cell Nuclear Antigen; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein