Activation of canonical Wnt signaling pathway promotes proliferation and self-renewal of rat hepatic oval cell line WB-F344 in vitro.
OBJECTIVE
To investigate the effect of activation of canonical Wnt signaling pathway on the proliferation and differentiation of hepatic oval cells in vitro.


METHODS
WB-F344 cells were treated with recombinant Wnt3a (20, 40, 80, 160, 200 ng/mL) in serum-free medium for 24 h. Cell proliferation was measured by Brdu incorporation analysis; untreated WB-F344 cells were taken as controls. After treatment with Wnt3a (160 ng/mL) for 24 h, subcellular localization and protein expression of beta-catenin in WB-F344 cells treated and untreated with Wnt3a were examined by immunofluorescence staining and Western blot analysis. CyclinD1 mRNA expression was determined by semi-quantitative reverse-transcript polymerase chain reaction (RT-PCR). The mRNA levels of some phenotypic markers (AFP, CK-19, ALB) and two hepatic nuclear factors (HNF-4, HNF-6) were measured by RT-PCR. Expressions of CK-19 and AFP protein were detected by Western blot analysis.


RESULTS
Wnt3a promoted proliferation of WB-F344 cells. Stimulation of WB-F344 cells with recombinant Wnt3a resulted in accumulation of the transcriptional activator beta-catenin, together with its translocation into the nuclei, and up-regulated typical Wnt target gene CyclinD1. After 3 d of Wnt3a treatment in the absence of serum, WB-F344 cells retained their bipotential to express several specific phenotypic markers of hepatocytes and cholangiocytes, such as AFP and CK-19, following activation of the canonical Wnt signaling pathway.


CONCLUSIONS
The canonical Wnt signaling pathway promotes proliferation and self-renewal of rat hepatic oval cells.
Zhang
Ying
Y
Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China.
Li
Xin-Min
XM
Zhang
Fu-Kui
FK
Wang
Bao-En
BE
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D019938:Cyclin D1 / Q000378:metabolism; D066298:In Vitro Techniques; D008099:Liver / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*; D051153:Wnt Proteins / Q000494:pharmacology / Q000502:physiology*; D060508:Wnt3 Protein; D051176:beta Catenin / Q000378:metabolism
D051153:Wnt Proteins; D060508:Wnt3 Protein; D051176:beta Catenin; D019938:Cyclin D1