The effect of hepatitis B virus X gene expression on response to growth inhibition by transforming growth factor-beta 1.
Hepatitis B virus X protein (HBx protein), which seems to be involved in hepatocarcinogenesis, was studied for its effect on cell growth regulation. We examined the response to growth inhibition of transforming growth factor beta 1 (TGF-beta 1) in HBx gene-introduced cells. HBx gene in pRc/CMV was transfected to mink lung epithelial cells (Mv1Lu cells) and a stable transformant was obtained. The inhibition rates of [3H] thymidine incorporation by addition of TGF-beta 1 (0.08 ng/ml) to parent cells and pRc/CMV-transfected cells were 34% and 26%, respectively. However, the inhibition rates in the HBx gene-transfected cells were 3-8%. The amount of TGF-beta type II receptor on the surface of HBx gene-transfected cells was about half of that on the parent or pRc/CMV-transfected cells. Our results indicated that expression of HBx gene reduces the response to growth inhibition by TGF-beta 1.
Oshikawa
O
O
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Tamura
S
S
Kawata
S
S
Ito
N
N
Tsushima
H
H
Kiso
S
S
Matsuda
Y
Y
Yamada
A
A
Tamai
S
S
Matsuzawa
Y
Y
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D015967:Gene Expression Regulation, Viral; D006131:Growth Inhibitors / Q000494:pharmacology; D006509:Hepatitis B / Q000235:genetics*; D008907:Mink; D012333:RNA, Messenger / Q000235:genetics; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D054334:Viral Regulatory and Accessory Proteins
D006131:Growth Inhibitors; D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein