Carbenoxolone inhibits DNA synthesis and collagen gene expression in rat hepatic stellate cells in culture.
OBJECTIVE
This study using primary-cultured rat hepatic stellate cells (HSCs) was aimed to reveal the effect of carbenoxolone and the other gap-junction blockers on the proliferation and activation of HSCs.


METHODS
HSC morphology was microscopically evaluated. DNA synthesis was determined by [3H]thymidine incorporation. Expression of HSC activation markers and cell cycle-related proteins was evaluated by Western blot. Collagen alpha1(I) mRNA expression was evaluated by quantitative reverse transcription polymerase chain reaction.


RESULTS
Carbenoxolone triggered the morphological change of activated HSCs without inducing apoptosis. Culture-induced DNA synthesis was suppressed to 22.6 and 8.51%, respectively, by 40 and 80 microM carbenoxolone. The other gap-junction blockers failed to affect the morphology and the DNA synthesis of activated HSCs. Carbenoxolone decreased the expression of cyclins D1/2 and cyclin-dependent kinases 4/6. Platelet-derived growth factor (PDGF)-BB-elicited DNA synthesis was reduced to 45.6 and 3.27%, respectively, by 40 and 80 microM carbenoxolone. Phosphorylation of c-Raf, MEK and mitogen-activated protein kinase, but not PDGF receptor beta, under PDGF-BB stimulation was attenuated by carbenoxolone. Collagen alpha1(I) mRNA expression was significantly reduced. In addition, carbenoxolone suppressed the activation process of quiescent HSCs.


CONCLUSIONS
Carbenoxolone reduced the DNA synthesis and the expression of collagen alpha1(I) mRNA in activated HSCs independently of its pharmacological action as gap-junction blocker.
Department of Gastroenterological Surgery, Graduate School of Medicine, Kyoto University, 54-Kawaracho, Shogoin, Sakyoku, Kyoto 606-8507, Japan.
Naoki
N
Uyama
Yasuyuki
Y
Shimahara
Hiroaki
H
Okuyama
Norifumi
N
Kawada
Shoko
S
Kamo
Kazuo
K
Ikeda
Yoshio
Y
Yamaoka
D000818:Animals; D000077214:Becaplermin; D015415:Biomarkers / Q000032:analysis; D002229:Carbenoxolone / Q000494:pharmacology*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics*; D017630:Connexins / Q000494:pharmacology; D004247:DNA / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D015870:Gene Expression / Q000187:drug effects*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D009829:Oleic Acids / Q000494:pharmacology; D009842:Oligopeptides; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects
D015415:Biomarkers; D018797:Cell Cycle Proteins; D017630:Connexins; D009829:Oleic Acids; D009842:Oligopeptides; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; C455880:gap 27 peptide; D000077214:Becaplermin; C029407:oleylamide; D003094:Collagen; D004247:DNA; D002229:Carbenoxolone