AIM:To investigate the apoptotic activities of casticin in hepatocellular carcinoma(HCC) cells and its molecular mechanisms.METHODS:PLC/PRF/5 and Hep G2 cell lines were cultured in vitro and the inhibitory effect of c...AIM:To investigate the apoptotic activities of casticin in hepatocellular carcinoma(HCC) cells and its molecular mechanisms.METHODS:PLC/PRF/5 and Hep G2 cell lines were cultured in vitro and the inhibitory effect of casticin on the growth of cells was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolim bromide(MTT) assay.The apoptotic cell death was examined using the cell apoptosis enzyme linked immunosorbent assay(ELISA) detection kit,flow cytometry(FCM) after propidium iodide(PI) staining and DNA agarose gel electrophoresis.The caspase activities were measured using ELISA.Reactive oxygen species(ROS) production was evaluated by FCM after dichlorodihydrofluorescein diacetate(DCFH-DA) probe labeling.Intracellular glutathione(GSH) content was measured using a glutathione assay kit.The expression of death receptor(DR)4 and DR5 proteins was analyzed by Western blotting and FCM.RESULTS:Casticin significantly inhibited the growth of human HCC(PLC/PRF/5 and Hep G2) cells in a dosedependent manner(P < 0.05).Casticin increased the percentage of the sub-G1 population in HCC cells in a concentration-dependent manner.The potency of casticin to PLC/PRF/5 cells was higher than that of 5-flurouracil(26.8% ± 4.8% vs 17.4% ± 5.1%) at 10 μmol/L for 24 h.Casticin increased the levels of Histone/DNA fragmentation and the levels of active caspase-3,-8 and-9 in a concentration-dependent manner(P < 0.05).Treatment with 30 μmol/L casticin for 24 h resulted in the formation of a DNA ladder.Casticin reduced the GSH content(P < 0.05),but did not affect the level of intracellular ROS in PLC/PRF/5 and Hep G2 cells.The thiol antioxidants,acetylcysteine(NAC) and GSH restored GSH content and attenuated casticin-induced apoptosis.In contrast,the nonthiol antioxidants,butylated hydroxyanisole and mannitol failed to do so.In the HCC cells treated with casticin for 24 h,DR5 protein level was increased.The expression of DR5 protein induced by casticin was inhibited by NAC.Pretreatment with DR5/Fc chimera protein,a blocking antibody,effectively attenuated the induction of apoptosis by casticin.CONCLUSION:Casticin-induced apoptosis of HCC cells is involved in GSH depletion and DR5 upregulation.展开更多
AIM： To investigate the effect of detachment of esophageal cancer cells from extracellular matrix on the localization of death receptor 5 （DR5） and apoptosis. METHODS： Anchorage-dependent EC9706 cells of esophagea...AIM： To investigate the effect of detachment of esophageal cancer cells from extracellular matrix on the localization of death receptor 5 （DR5） and apoptosis. METHODS： Anchorage-dependent EC9706 cells of esophageal squamous cell carcinoma were pretreated or not treated with brefeldin A. Detached cells were harvested by ethylenediaminetetraacetic acid digestion. Expression and localization of DR5 in these cells were determined by immunocytochemical and immunofluorescence assays, as well as flow cytometry analysis. Apoptosis of EC9706 cells was detected by flow cytometry after stained with fluorescein isothiocyanate-labeled annexin V/propidium iodide. Activation of caspase 8 was detected by Western blot analysis. RESULTS： Immunocytochemical assay indicated that DR5 was predominantly perinuclear in adherent cells but was mainly localized in cell membrane in detached cells. In addition, immunofluorescence assay also confirmed the above-mentioned results, and further demonstrated that DR5 was present in the form of coarse granules in detached cells, but in the form of fine granules in adherent cells. Cytometry analysis revealed higher levels of DR5 expression on the surfaces of brefeldin-A-untreated cells than on the surfaces of brefeldin-A-treated cells, but brefeldin A treatment did not affect the total DR5 expression levels. Moreover, nocodazole did not influence the extracelluar DR5 expression levels in EC9706 cells. Apoptosis assay revealed that detached cells were more sensitive to DR5 antibody-induced apoptosis than adherent ceils. Western blotting showed that caspase 8 was activated in temporarily detached cells 4 h earlier than in adherent cells. CONCLUSION： Progress from adhesion to detachment of EC9706 cells causes DR5 relocalization, and promotes cytoplasmic translocation of DR5 to cell surfaces via a Golgi-dependent pathway. Moreover, it might also result in DR5 aggregation to render apoptosis of detached cells.展开更多
Polygonum cuspidatum is used as a traditional medicinal herb for the therapy of various diseases including several types of cancers. In the present study, we focused on addressing the anti-cancer activity and molecula...Polygonum cuspidatum is used as a traditional medicinal herb for the therapy of various diseases including several types of cancers. In the present study, we focused on addressing the anti-cancer activity and molecular mechanism of methanol extract of Polygonum cuspidatum (MEPC) in HSC-2 human oral cancer cells. The effect of MEPC on oral cancer cells was estimated by 3-(4,5-dimethylthiazol-20yl)-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium (MTS) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining and Western blot analysis. MEPC inhibited the cell viability and induced apoptosis through the induction of death receptor (DR) 5. MEPC also increased the expression of C/EBP homologous protein/growth arrest and the DNA damage-inducible gene 153 (CHOP), a transcription factor induced by ER stress. Thus, we concluded that the induction of CHOP leading to DR5 up-regulation is required for the anti-cancer activity of MEPC in HSC-2 cells and MEPC may be a promising drug candidate for oral cancer.展开更多
Tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） is a promising anti-cancer agent. Epigallocatechin-3-gallate （EGCG） is a polyphenolic constituent of green tea. In this study, inhibitory effect of c...Tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） is a promising anti-cancer agent. Epigallocatechin-3-gallate （EGCG） is a polyphenolic constituent of green tea. In this study, inhibitory effect of combined use of EGCG and TRAIL on human melanoma A375 cells was examined and the possible mechanism investigated. The cells were divided into 4 groups： control group, EGCG group （EGCG： 10, 20 μg/mL）, TRAIL group （TRAIL： 25 ng/mL） and EGCG＋TRAIL group （combined group）. The growth inhibition was measured in the A375 cells treated with different concentrations of TRAIL （（25, 50, 75, 100, 125, 150 ng/mL） by MTT assay. The apoptosis was assessed by flow cytometry. The expressions of DR4 and DR5 were detected by flow cytometry and western blotting. The activities of caspase-8 and caspase-3 were determined by colorimetric assay. The results showed that TRAIL could dose-dependently inhibit the growth of A375 cells and the IC50 of TRAIL was 150 ng/mL. The apoptosis rate was 11.8% in the TRAIL group, 5%–7% in the EGCG group and 48.9%–59.1% in the combined group. Significant difference was found in the apoptosis rate between the combined group and the EGCG or TRAIL group （P〈0.05 for each）. The expression of DR4 instead of DR5 was significantly increased in the EGCG group. The activity of caspase-3 rather than caspase-8 was substantially enhanced in the EGCG group. These results suggest that EGCG is useful for the TRAIL-based treatment for melanoma.展开更多
基金Supported by The Scientifi c Research Project of Hunan Provincial Administration Bureau of Traditional Chinese Medicine,No. 2010081Scientific Research Project of Hunan Provincial Health Department,No. B2010-030Major Projects of Scien-tific Research of Hunan Provincial Department of Education,No. 09A054
文摘AIM:To investigate the apoptotic activities of casticin in hepatocellular carcinoma(HCC) cells and its molecular mechanisms.METHODS:PLC/PRF/5 and Hep G2 cell lines were cultured in vitro and the inhibitory effect of casticin on the growth of cells was detected by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolim bromide(MTT) assay.The apoptotic cell death was examined using the cell apoptosis enzyme linked immunosorbent assay(ELISA) detection kit,flow cytometry(FCM) after propidium iodide(PI) staining and DNA agarose gel electrophoresis.The caspase activities were measured using ELISA.Reactive oxygen species(ROS) production was evaluated by FCM after dichlorodihydrofluorescein diacetate(DCFH-DA) probe labeling.Intracellular glutathione(GSH) content was measured using a glutathione assay kit.The expression of death receptor(DR)4 and DR5 proteins was analyzed by Western blotting and FCM.RESULTS:Casticin significantly inhibited the growth of human HCC(PLC/PRF/5 and Hep G2) cells in a dosedependent manner(P < 0.05).Casticin increased the percentage of the sub-G1 population in HCC cells in a concentration-dependent manner.The potency of casticin to PLC/PRF/5 cells was higher than that of 5-flurouracil(26.8% ± 4.8% vs 17.4% ± 5.1%) at 10 μmol/L for 24 h.Casticin increased the levels of Histone/DNA fragmentation and the levels of active caspase-3,-8 and-9 in a concentration-dependent manner(P < 0.05).Treatment with 30 μmol/L casticin for 24 h resulted in the formation of a DNA ladder.Casticin reduced the GSH content(P < 0.05),but did not affect the level of intracellular ROS in PLC/PRF/5 and Hep G2 cells.The thiol antioxidants,acetylcysteine(NAC) and GSH restored GSH content and attenuated casticin-induced apoptosis.In contrast,the nonthiol antioxidants,butylated hydroxyanisole and mannitol failed to do so.In the HCC cells treated with casticin for 24 h,DR5 protein level was increased.The expression of DR5 protein induced by casticin was inhibited by NAC.Pretreatment with DR5/Fc chimera protein,a blocking antibody,effectively attenuated the induction of apoptosis by casticin.CONCLUSION:Casticin-induced apoptosis of HCC cells is involved in GSH depletion and DR5 upregulation.
基金Supported by National Natural Science Foundation of China,No. 30571697Outstanding Individual Innovation Foundation of Henan Province,China,No.074200510014
文摘AIM： To investigate the effect of detachment of esophageal cancer cells from extracellular matrix on the localization of death receptor 5 （DR5） and apoptosis. METHODS： Anchorage-dependent EC9706 cells of esophageal squamous cell carcinoma were pretreated or not treated with brefeldin A. Detached cells were harvested by ethylenediaminetetraacetic acid digestion. Expression and localization of DR5 in these cells were determined by immunocytochemical and immunofluorescence assays, as well as flow cytometry analysis. Apoptosis of EC9706 cells was detected by flow cytometry after stained with fluorescein isothiocyanate-labeled annexin V/propidium iodide. Activation of caspase 8 was detected by Western blot analysis. RESULTS： Immunocytochemical assay indicated that DR5 was predominantly perinuclear in adherent cells but was mainly localized in cell membrane in detached cells. In addition, immunofluorescence assay also confirmed the above-mentioned results, and further demonstrated that DR5 was present in the form of coarse granules in detached cells, but in the form of fine granules in adherent cells. Cytometry analysis revealed higher levels of DR5 expression on the surfaces of brefeldin-A-untreated cells than on the surfaces of brefeldin-A-treated cells, but brefeldin A treatment did not affect the total DR5 expression levels. Moreover, nocodazole did not influence the extracelluar DR5 expression levels in EC9706 cells. Apoptosis assay revealed that detached cells were more sensitive to DR5 antibody-induced apoptosis than adherent ceils. Western blotting showed that caspase 8 was activated in temporarily detached cells 4 h earlier than in adherent cells. CONCLUSION： Progress from adhesion to detachment of EC9706 cells causes DR5 relocalization, and promotes cytoplasmic translocation of DR5 to cell surfaces via a Golgi-dependent pathway. Moreover, it might also result in DR5 aggregation to render apoptosis of detached cells.
文摘Polygonum cuspidatum is used as a traditional medicinal herb for the therapy of various diseases including several types of cancers. In the present study, we focused on addressing the anti-cancer activity and molecular mechanism of methanol extract of Polygonum cuspidatum (MEPC) in HSC-2 human oral cancer cells. The effect of MEPC on oral cancer cells was estimated by 3-(4,5-dimethylthiazol-20yl)-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium (MTS) assay, 4’-6-diamidino-2-phenylindole (DAPI) staining and Western blot analysis. MEPC inhibited the cell viability and induced apoptosis through the induction of death receptor (DR) 5. MEPC also increased the expression of C/EBP homologous protein/growth arrest and the DNA damage-inducible gene 153 (CHOP), a transcription factor induced by ER stress. Thus, we concluded that the induction of CHOP leading to DR5 up-regulation is required for the anti-cancer activity of MEPC in HSC-2 cells and MEPC may be a promising drug candidate for oral cancer.
文摘Tumor necrosis factor-related apoptosis-inducing ligand （TRAIL） is a promising anti-cancer agent. Epigallocatechin-3-gallate （EGCG） is a polyphenolic constituent of green tea. In this study, inhibitory effect of combined use of EGCG and TRAIL on human melanoma A375 cells was examined and the possible mechanism investigated. The cells were divided into 4 groups： control group, EGCG group （EGCG： 10, 20 μg/mL）, TRAIL group （TRAIL： 25 ng/mL） and EGCG＋TRAIL group （combined group）. The growth inhibition was measured in the A375 cells treated with different concentrations of TRAIL （（25, 50, 75, 100, 125, 150 ng/mL） by MTT assay. The apoptosis was assessed by flow cytometry. The expressions of DR4 and DR5 were detected by flow cytometry and western blotting. The activities of caspase-8 and caspase-3 were determined by colorimetric assay. The results showed that TRAIL could dose-dependently inhibit the growth of A375 cells and the IC50 of TRAIL was 150 ng/mL. The apoptosis rate was 11.8% in the TRAIL group, 5%–7% in the EGCG group and 48.9%–59.1% in the combined group. Significant difference was found in the apoptosis rate between the combined group and the EGCG or TRAIL group （P〈0.05 for each）. The expression of DR4 instead of DR5 was significantly increased in the EGCG group. The activity of caspase-3 rather than caspase-8 was substantially enhanced in the EGCG group. These results suggest that EGCG is useful for the TRAIL-based treatment for melanoma.
