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
Objective:To evaluate the 15-lipoxygenase inhibitory activity of the methanol leaf extracts of Commelina benghalensis,Tradescantia fluminensis(T.fluminensis)and Tradescantia zebrina.Method:The inhibitory activity was ...Objective:To evaluate the 15-lipoxygenase inhibitory activity of the methanol leaf extracts of Commelina benghalensis,Tradescantia fluminensis(T.fluminensis)and Tradescantia zebrina.Method:The inhibitory activity was evaluated using a spectrophotometric assay by observing the increase in absorbance at 234 nm due to the formation of the product 13-hydroperoxyoctadecadienoic acid.The extracts were also tested for the presence of terpenoids,saponins,tannins,flavonoids,steroids,phenolic compounds,alkaloids and cardiac glycosides.Results:All the extracts inhibited the action of 15-lipoxygenase at a concentration of 0.2μg/mL.T.fluminensis and Tradescantia zebrina exhibited higher than 50%inhibition with T.fluminensis at 87.2%.T.fluminensis was partitioned with ethyl acetate and hexane and their IC_(50)values were determined at 8.72μg/mL and 98.04μg/mL,respectively.Conclusions:T.fluminensis is a potentially good source of 15-lipoxygenase inhibitors.展开更多
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.
基金Supported by the University of the Philippines Diliman through the Natural Sciences Research Institute(Grant No.CHE-09-2-02)
文摘Objective:To evaluate the 15-lipoxygenase inhibitory activity of the methanol leaf extracts of Commelina benghalensis,Tradescantia fluminensis(T.fluminensis)and Tradescantia zebrina.Method:The inhibitory activity was evaluated using a spectrophotometric assay by observing the increase in absorbance at 234 nm due to the formation of the product 13-hydroperoxyoctadecadienoic acid.The extracts were also tested for the presence of terpenoids,saponins,tannins,flavonoids,steroids,phenolic compounds,alkaloids and cardiac glycosides.Results:All the extracts inhibited the action of 15-lipoxygenase at a concentration of 0.2μg/mL.T.fluminensis and Tradescantia zebrina exhibited higher than 50%inhibition with T.fluminensis at 87.2%.T.fluminensis was partitioned with ethyl acetate and hexane and their IC_(50)values were determined at 8.72μg/mL and 98.04μg/mL,respectively.Conclusions:T.fluminensis is a potentially good source of 15-lipoxygenase inhibitors.
