AIM:To investigate the mechanism by which galangin,a polyphenolic compound derived from medicinal herbs,induces apoptosis of hepatocellular carcinoma(HCC) cells.METHODS:The 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyl-t...AIM:To investigate the mechanism by which galangin,a polyphenolic compound derived from medicinal herbs,induces apoptosis of hepatocellular carcinoma(HCC) cells.METHODS:The 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability.Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy.Protein expressions were detected by Western blotting.To confirm the apoptotic pathway mediated by galangin,cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression.RESULTS:Galangin(46.25-370.0 μmol/L) exerted an anti-proliferative effect,induced apoptosis,and decreased mitochondrial membrane potential in a dose and time-dependent manner.Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria,which released apoptosis-inducing factor and cytochrome c into the cytosol.Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis,while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis.CONCLUSION:Our data suggests that galangin mediates apoptosis through a mitochondrial pathway,and may be a potential chemotherapeutic drug for the treatment of HCC.展开更多
BACKGROUND:12-lipoxygenase(12-LOX) has been reported to be an important gene in cancer cell proliferation and survival,and tumor metastasis.However,its role in hepatocellular carcinoma(HCC) cells remains unknown.METHO...BACKGROUND:12-lipoxygenase(12-LOX) has been reported to be an important gene in cancer cell proliferation and survival,and tumor metastasis.However,its role in hepatocellular carcinoma(HCC) cells remains unknown.METHODS:Expression of 12-LOX was assessed in a diethylnitrosamine-induced rat HCC model,and in SMMC-7721,HepG2 and L-02 cells using immunohistochemical staining and reverse transcriptase-polymerase chain reaction(RT-PCR).GST-π and Ki-67 were determined in vivo by immunohistochemical staining.Apoptosis was evaluated by TUNEL assay.Cell viability and apoptosis were determined by MTT assay and flow cytometry,respectively.Apoptosis-related proteins in SMMC-7721 and HepG2 cells were detected by Western blotting.RESULTS:Immunohistochemical staining and RT-PCR showed that 12-LOX was over-expressed in rat HCC and two HCC cell lines,while the expression was inhibited by baicalein,a specific inhibitor of 12-LOX.Baicalein inhibited cell proliferation and induced apoptosis in rat HCC and both cell lines in a dose-and time-dependent manner.Our in vivo study demonstrated that baicalein also reduced neoplastic nodules.Mechanistically,baicalein reduced Bcl-2 protein expression coupled with a slight increase of the expression of Bax and activation of caspase-3.Furthermore,baicalein inhibited the activation of ERK-1/2(phosphorylated).Interestingly,the effects of baicalein were reversed by 12(S)-HETE,a metabolite of 12-LOX.CONCLUSIONS:Inhibition of 12-LOX leads to reduced numbers of HCC cells,partially caused by increased apoptosis.12-LOX may be a potential molecular target for HCC prevention and treatment.展开更多
基金Supported by The administration of traditional Chinese medicine of Guangdong province,China,No.1050047
文摘AIM:To investigate the mechanism by which galangin,a polyphenolic compound derived from medicinal herbs,induces apoptosis of hepatocellular carcinoma(HCC) cells.METHODS:The 3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay was used to measure cell viability.Apoptosis was evaluated by in situ uptake of propidium iodide and Hoechst 33258 and was then detected by fluorescence microscopy.Protein expressions were detected by Western blotting.To confirm the apoptotic pathway mediated by galangin,cells were transfected by bcl-2 gene to overexpress Bcl-2 or siRNA to down-regulate Bcl-2 expression.RESULTS:Galangin(46.25-370.0 μmol/L) exerted an anti-proliferative effect,induced apoptosis,and decreased mitochondrial membrane potential in a dose and time-dependent manner.Treatment with galangin induced apoptosis by translocating the pro-apoptotic protein Bax to the mitochondria,which released apoptosis-inducing factor and cytochrome c into the cytosol.Overexpression of Bcl-2 attenuated galangin-induced HepG2 cell apoptosis,while decreasing Bcl-2 expression enhanced galangin-induced cell apoptosis.CONCLUSION:Our data suggests that galangin mediates apoptosis through a mitochondrial pathway,and may be a potential chemotherapeutic drug for the treatment of HCC.
基金supported by grants from the National Natural Science Foundation of China(81000998)the Natural Science Foundation of Hubei Province,China(2007ABA248)the Foundation of the Ministry of Education of China for New Teachers(20090141120003)
文摘BACKGROUND:12-lipoxygenase(12-LOX) has been reported to be an important gene in cancer cell proliferation and survival,and tumor metastasis.However,its role in hepatocellular carcinoma(HCC) cells remains unknown.METHODS:Expression of 12-LOX was assessed in a diethylnitrosamine-induced rat HCC model,and in SMMC-7721,HepG2 and L-02 cells using immunohistochemical staining and reverse transcriptase-polymerase chain reaction(RT-PCR).GST-π and Ki-67 were determined in vivo by immunohistochemical staining.Apoptosis was evaluated by TUNEL assay.Cell viability and apoptosis were determined by MTT assay and flow cytometry,respectively.Apoptosis-related proteins in SMMC-7721 and HepG2 cells were detected by Western blotting.RESULTS:Immunohistochemical staining and RT-PCR showed that 12-LOX was over-expressed in rat HCC and two HCC cell lines,while the expression was inhibited by baicalein,a specific inhibitor of 12-LOX.Baicalein inhibited cell proliferation and induced apoptosis in rat HCC and both cell lines in a dose-and time-dependent manner.Our in vivo study demonstrated that baicalein also reduced neoplastic nodules.Mechanistically,baicalein reduced Bcl-2 protein expression coupled with a slight increase of the expression of Bax and activation of caspase-3.Furthermore,baicalein inhibited the activation of ERK-1/2(phosphorylated).Interestingly,the effects of baicalein were reversed by 12(S)-HETE,a metabolite of 12-LOX.CONCLUSIONS:Inhibition of 12-LOX leads to reduced numbers of HCC cells,partially caused by increased apoptosis.12-LOX may be a potential molecular target for HCC prevention and treatment.
