Hepatocyte growth factor-induced proliferation of hepatic stem-like cells depends on activation of NF-kappaB.
OBJECTIVE
Hepatocyte growth factor (HGF) regulates proliferation of hepatic stem cells. Transcription factor nuclear factor kappa B (NF-kappaB) has been demonstrated as a key mediator for cell growth regulation. We investigated the role of NF-kappaB in HGF-mediated cellular proliferation responses in a rat liver-derived hepatic stem-like cell line WB-F344.


METHODS
Cell proliferation was determined by incorporation of [3H]thymidine. Phosphorylation of ERK1/2, p38 MAPK, Akt and IkappaBalpha by HGF stimulation was detected by Western blotting. NF-kappaB activation was determined by electrophoretic mobility shift assay and NF-kappaB-mediated SEAP reporter assay. NF-kappaB activation was inhibited by treatment with an IkappaBalpha dominant-negative vector or inhibitor BAY-11-7082.


RESULTS
We found that stimulation of WB-F344 cells with HGF promoted cell proliferation and effectively protected WB-F344 cells from apoptosis induced by TNF-alpha. We also observed activation of ERK1/2, p38 MAPK, Akt and NF-kappaB signaling pathways by HGF in WB-F344 cells. HGF-induced cell proliferation was partly blocked by pre-treatment of the cells with inhibitors against MEK1 or p38 MAPK, and completely blocked using an inhibitor for NF-kappaB activity. Furthermore, it was demonstrated that IkappaB mutant that suppressed NF-kappaB activity completely blocked HGF-induced cell proliferation.


CONCLUSIONS
NF-kappaB activity is required for HGF-induced proliferation in hepatic stem-like cell line WB-F344, and this activity requires ERK1/2 and p38 MAPK pathways.
Yao
Peng
P
Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, China.
Zhan
Yiqun
Y
Xu
Wangxiang
W
Li
Changyan
C
Yue
Peibin
P
Xu
Chengwang
C
Hu
Darong
D
Qu
Cheng-Kui
CK
Qu
Chengkui
C
Yang
Xiaoming
X
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D017228:Hepatocyte Growth Factor / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D022781:Hepatocytes / Q000166:cytology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D013234:Stem Cells / Q000166:cytology*; D014158:Transcription, Genetic / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases
D016328:NF-kappa B; D011518:Proto-Oncogene Proteins; D017228:Hepatocyte Growth Factor; D004247:DNA; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases