A mutant of hepatitis B virus X protein (HBx Delta 127) enhances hepatoma cell migration via osteopontin involving 5-lipoxygenase.
OBJECTIVE
To explore a novel function of a mutant of the hepatitis B virus X protein (HBx Delta 127) in the promotion of hepatoma cell migration.


METHODS
The effect of HBx Delta 127 and wild type HBx on the migration ability of hepatoblastoma HepG2 cells were examined using wound healing assays in stable transfection systems. The full-length osteopontin(OPN) promoter sequence was cloned into the pGL3-Basic plasmid. The promoter activities of OPN in stably HBx Delta 127-transfected hepatoblastoma HepG2 (HepG2-X Delta 127) and hepatocellular carcinoma H7402 (H7402-X Delta 127) cells were determined using luciferase reporter gene assays. The mRNA expression levels of OPN were detected by RT-PCR. And the effect of MK886, a specific inhibitor of 5-lipoxygenase (5-LOX), on OPN promoter activity and mRNA expression in HepG2-X Delta 127 and H7402-X Delta 127 cells were examined using luciferase reporter gene assays and RT-PCR, respectively. Finally, the migration ability of HepG2-X Delta 127 was observed after treatment with siRNA targeting OPN mRNA and HBx mRNA using wound healing assays.


RESULTS
HepG2-X Delta 127 cells exhibited a greater capacity for wound repair compared to HepG2-X cells. The promoter activity and mRNA expression levels of OPN were also increased in HepG2-X Delta 127 and H7402-X Delta 127 cells. Moreover, MK886 abolished the HBx Delta 127-mediated upregulation of OPN. Wound healing assays demonstrated that the migration ability of HepG2-X Delta 127 cells can be suppressed by treatment with siRNA targeting OPN mRNA and siRNA targeting HBx mRNA.


CONCLUSIONS
HBx Delta 127 strongly promotes hepatoma cell migration via activation of OPN involving 5-LOX.
Zhang
Xuan
X
Department of Cancer Research, Key Laboratory of Molecular Microbiology and Technology of Ministry of Education, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
Ye
Li-hong
LH
Zhang
Xiao-dong
XD
D001094:Arachidonate 5-Lipoxygenase / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D045744:Cell Line, Tumor; D002465:Cell Movement; D056945:Hep G2 Cells; D006515:Hepatitis B virus / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009154:Mutation; D053495:Osteopontin / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation; D054334:Viral Regulatory and Accessory Proteins
D012333:RNA, Messenger; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D053495:Osteopontin; D001094:Arachidonate 5-Lipoxygenase