AIM： To investigate in vitro effects and mechanisms of silibinin on hepatocellular carcinoma （HCC） cell growth, METHODS： Human HCC cell lines were treated with different doses of silibinin. The effects of silibini...AIM： To investigate in vitro effects and mechanisms of silibinin on hepatocellular carcinoma （HCC） cell growth, METHODS： Human HCC cell lines were treated with different doses of silibinin. The effects of silibinin on HCC cell growth and proliferation, apoptosis, cell cycle progression, histone acetylation, and other related signal transductions were systematically examined. RESULTS： We demonstrated that silibinin significantly reduced the growth of HUH7, HepG2, Hep3B, and PLC/PRF/5 human hepatoma cells. Silibinin-reduced HuH7 cell growth was associated with significantly up- regulated p21/CDK4 and p27/CDK4 complexes, down- regulated Rb-phosphorylation and E2F1/DP1 complex. Silibinin promoted apoptosis of HuH7 cells that was associated with down-regulated survivin and upregulated activated caspase-3 and -9. Silibinin＇s antiangiogenic effects were indicated by down-regulated metalloproteinase-2 （MMP2） and CD34. We found that silibinin-reduced growth of HuH7 cells was associated with increased activity of phosphatase and tensin homolog deleted on chromosome ten （PTEN） and decreased p-Akt production, indicating the role of PTEN/ PI3K/Akt pathway in silibinin-mediated anti-HCC effects. We also demonstrated that silibinin increased acetylation of histone H3 and H4 （AC-H3 and AC-H4）, indicating a possible role of altered histone acetylation in silibininreduced HCC cell proliferation. CONCLUSION： Our results defined silibinin＇s in vitro anti-HCC effects and possible mechanisms, and provided a rationale to further test silibinin for HCC chemoprevention.展开更多
The mitogen activated protein kinases-extracellular signal regulated kinases （MAPK-ERK） pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 ce...The mitogen activated protein kinases-extracellular signal regulated kinases （MAPK-ERK） pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell line Conl with an HCV replicon, we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-a signalling. Epithelial growth factor （EGF） was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Conl cells. It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site. Consistently, a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfeetion assays. Thus, the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication. In addition, cyclin-dependent kinases （CDKs） downstream of ERK may also be involved in the modulation of HCV replication since roscovitine, an inhibitor of CDKs had a similar effect to that of U0126. Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels. Further, the replication of HCV replicon in Conl cells was inhibited by IFN-~z. The inhibitory effect of IFN-CZ could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs. It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.展开更多
基金Supported by UCI institutional research grants from GI Division Chao Family Comprehensive Cancer Center(K.-Q.H.)
文摘AIM： To investigate in vitro effects and mechanisms of silibinin on hepatocellular carcinoma （HCC） cell growth, METHODS： Human HCC cell lines were treated with different doses of silibinin. The effects of silibinin on HCC cell growth and proliferation, apoptosis, cell cycle progression, histone acetylation, and other related signal transductions were systematically examined. RESULTS： We demonstrated that silibinin significantly reduced the growth of HUH7, HepG2, Hep3B, and PLC/PRF/5 human hepatoma cells. Silibinin-reduced HuH7 cell growth was associated with significantly up- regulated p21/CDK4 and p27/CDK4 complexes, down- regulated Rb-phosphorylation and E2F1/DP1 complex. Silibinin promoted apoptosis of HuH7 cells that was associated with down-regulated survivin and upregulated activated caspase-3 and -9. Silibinin＇s antiangiogenic effects were indicated by down-regulated metalloproteinase-2 （MMP2） and CD34. We found that silibinin-reduced growth of HuH7 cells was associated with increased activity of phosphatase and tensin homolog deleted on chromosome ten （PTEN） and decreased p-Akt production, indicating the role of PTEN/ PI3K/Akt pathway in silibinin-mediated anti-HCC effects. We also demonstrated that silibinin increased acetylation of histone H3 and H4 （AC-H3 and AC-H4）, indicating a possible role of altered histone acetylation in silibininreduced HCC cell proliferation. CONCLUSION： Our results defined silibinin＇s in vitro anti-HCC effects and possible mechanisms, and provided a rationale to further test silibinin for HCC chemoprevention.
基金supported by a joint grant of Chinese Academy of Science and Deutsche Akademische Austausch Dienstthe National Basic Research Priorities Program ofChina(2009CB522501,2005CB522901,2007CB512901)
文摘The mitogen activated protein kinases-extracellular signal regulated kinases （MAPK-ERK） pathway is involved in regulation of multiple cellular processes including the cell cycle. In the present study using a Huh7 cell line Conl with an HCV replicon, we have shown that the MAPK-ERK pathway plays a significant role in the modulation of HCV replication and protein expression and might influence IFN-a signalling. Epithelial growth factor （EGF） was able to stimulate ERK activation and decreased HCV RNA load while a MAPK-ERK pathway inhibitor U0126 led to an elevated HCV RNA load and higher NS5A protein amounts in Conl cells. It could be further demonstrated that the inhibition of the MAPK-ERK pathway facilitated the translation directed by the HCV internal ribosome entry site. Consistently, a U0126 treatment enhanced activity of the HCV reporter replicon in transient transfeetion assays. Thus, the MAPK-ERK pathway plays an important role in the regulation of HCV gene expression and replication. In addition, cyclin-dependent kinases （CDKs） downstream of ERK may also be involved in the modulation of HCV replication since roscovitine, an inhibitor of CDKs had a similar effect to that of U0126. Modulation of the cell cycle progression by cell cycle inhibitor or RNAi resulted consistently in changes of HCV RNA levels. Further, the replication of HCV replicon in Conl cells was inhibited by IFN-~z. The inhibitory effect of IFN-CZ could be partly reversed by pre-incubation of Con-1 cells with inhibitors of the MAPK-ERK pathway and CDKs. It could be shown that the MAPK-ERK inhibitors are able to partially modulate the expression of interferon-stimulated genes.
