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AIM: To investigate the inhibitory effects of endoplasmic reticulum stress(ERS) and TRAIL on hepatic stellate cells in vitro and how their interaction affect the apoptosis of hepatic stellate cells. METHODS: Take thapsigargin (TG) as the endoplasmic reticulum stress-inducing agents, ursodeoxycholic acid (UDCA) for the endoplasmic reticulum stress inhibitors, SP600125 as a c-Jun N-terminal kinase(JNK) inhibitor, HSC-T6 cells were divided into normal control group, DMSO group, TRAIL group, TG group, UDCA group, siCHOP group and SP600125 group. The apoptosis rate of HSC-T6 cell was detected by flow cytometry. Small interference RNA was applied to silence C/EBP homologous protein(CHOP) gene. The protein expression levels of Caspase-8 were detected by immunohistochemistry method. The ERS marker protein CHOP and TRAIL receptor DR5 expression levels were determined by RT-PCR and Western blot. RESULTS:TG (1 μmol/L, 2 μmol/L, 4 μmol/L, 8 μmol/L, 16 μmol/L) increased cell apoptosis rate of HSC-T6. RT-PCR and Western blot showed that the endoplasmic reticulum stress protein marker CHOP could induce the upregulation of TRAIL receptor DR5 and Caspase-8. Moreover, siCHOP and the JNK inhibitor SP600125 could reduce the expression of DR5 and Caspase-8 in HSC cells. CONCLUSION: These results indicated that CHOP and JNK may be a potential factor regulating DR5 expression, and play an important role in the process of apoptosis of hepatic stellate cells.
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AIM:To investigate the effects of evodiamine on the growth and apoptosis of human hepatocellular carcinoma Huh7 cells,and to illustrate the molecular mechanism that evodiamine enhances antitumor activity of tumors nec -rosis factor-related apoptosis-inducing ligand(TRAIL)in Huh7 cells.METHODS: The cell viability was measured by MTT assay.The cell cycle distribution was analyzed by flow cytometry.The apoptosis rate was determined by TUNEL stai-ning.The protein levels of cell cycle-and apoptosis-related proteins were detected by Western blot analysis.RESULTS:Treatment of Huh7 cells with evodiamine reduced the cell viability(P<0.05).Evodiamine induced cell cycle arrest in G2/M phase by upregulation of p27,cyclin B1, cell division cycle protein 2(Cdc2)and p-Cdc2.Evodiamine triggered apoptosis accompanied by cleavage of caspase-3 and poly(ADP-ribose)polymerase(PARP).Combination of evodiamine with TRAIL significantly reduced the cell viability and increased cleavage of caspase -3 and PARP as compared with the use of each agent alone.Moreover,evodiamine increased the expression of death receptor 5(DR5)in the Huh7 cells.CON-CLUSION:Evodiamine inhibits the cell growth by reducing the cell viability and inducing cell cycle arrest.Evodiamine also triggers cell apoptosis and enhances the sensitivity of Huh 7 cells to TRAIL by upregulating the expression of DR5.
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AIM:To investigate the synergistic effect of imperatorin on enhancing the anti -tumor effect of TNF-related apoptosis-inducing ligand(TRAIL)on breast cancer and the mechanisms.METHODS:T-47D and MCF-7 breast cancer cells were divided into control group ,imperatorin group,TRAIL group,imperatorin+TRAIL group and imperatorin+TRAIL+death receptor 5(DR5)siRNA group.The viability of T-47D and MCF-7 cells was measured by MTT assay. The apoptosis and mitochondrial membrane potential in T-47D cells were analyzed by flow cytometry.Western blot and flow cytometry analysis were performed to evaluate the expression of DR 5 on T-47D cell surface and the activation of caspase-8 and caspase-3.RESULTS:Imperatorin significantly enhanced the inhibition of cell viability induced by TRAIL of T -47D and MCF-7 cells,and significantly increased the apoptosis of T-47D cells induced by TRAIL.Imperatorin treatment ob-viously induced upregulation of DR5 expression and production of reactive oxygen species in the T-47D cells.In addition,imperatorin enhanced the TRAIL-induced damage of mitochondrial membrane potential and activation of caspase -8 and caspase-3.CONCLUSION:Imperatorin enhances the anti-tumor effect of TRAIL on breast cancer via upregulating the ex-pression of DR5.
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Objective To explore the effect of chloroquine on death receptor 5 (DR5) expression of hepatocellular carcinoma Huh7 cells and cell proliferation and apoptosis induced by tumor necrosis factor related apoptosis-inducing ligand (TRAIL).Methods Huh7 cells were divided into four groups:the control group (1∶1 000 dimethyl sulfoxide),TRAIL group (50 μg/L),chloroquine group (10 μmol/L) and TRAIL +chloroquine group (TRAIL 50 μg/L + chloroquine 10 μmol/L).Thiazolyl blue tetrazolium bromide (MTT) assay was used to determine the proliferation activity of cells,immunofluorescence was used to detect the expression of DR5,4',6-diamidino-2-phenylindole (DAPI) staining was used to observe cell apoptosis and Western blot was used to detect the expression of cleaved poly ADP-ribose polymerase (PARP).Results TRAIL treatment could decrease Huh7 cells proliferation activity;when compared with the cell viability in the control group,the cell proliferation inhibition rate of chloroquine group,TRAIL group and TRAIL+ chloroquine group was (89±8) ％,(53±10) ％ and (27±7) ％,respectively;compared with TRAIL group alone,cell proliferation activity was decreased in TRAIL+ chloroquine group (t =3.922,P =0.017).The expression of DR5 was upregulated in chloroquine group,and the cell apoptosis signaling was activated in TRAIL + chloroquine group.The cell apoptosis rate of TRAIL group and TRAIL + chloroquine group was (10.0±2.3) ％ and (20.4±4.0) ％,respectively,and there was a statistical difference (t =3.894,P =0.018).Conclusion Chloroquine can enhance the cell chemosensitivity to TRAIL treatment by upregulating the expression of DR5 in Huh7 cells.
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OBJECTIVE TNF- related apoptosis- inducing ligand(TRAIL)is a promising cancer therapeutic agent due to its minimal toxicity to normal tissues and remarkable apoptotic activity in tumors. However, most breast cancer cells are resistant to TRAIL- induced apoptosis. Our objectives are to investigate the underlying molecular mechanisms and to develop strategies to overcome such resistance. METHODS To identify modulators of TRAIL-induced apoptosis, we carried out a genome wide siRNA screen. To validate the screening result, we either silenced or overexpressed the identified genes in various breast cancer cells and changes in growth and TRAIL-induced cell apoptosis were determined in vitro and in an orthotopic xenograft mouse model. Finally, we investigated whether small molecules targeting the identified genes improve the effectiveness of TRAIL-therapy. RESULTS We unexpectedly identified androgen receptor (AR) to be responsible for TRAIL resistance. While AR is classically viewed as the key factor in prostate cancer progression, we found that AR expression levels were markedly elevated in human invasive breast cancer specimens including triple- negative breast cancers (TNBC) that are highly aggressive with poor prognosis. Importantly, breast cancer cell lines express different levels of AR that correlated with their TRAIL resistance. AR overexpression in MDA- MB- 231 and MDA- MB- 436 cells suppressed the TRAIL sensitivity whereas knockdown of AR rendered MCF-7 and MDA-MB-453 cells sensitive to TRAIL-induced apoptosis. AR overexpression also induced TRAIL resistance in breast tumors in vivo. Further, we observed an upregulation of the TRAIL receptor, death receptor 5 (DR5) in breast cancer cells, following the removal or inhibition of AR by its antagonists Casodex and MDV3100. Treatment with AR antagonists also enhanced TRAIL- induced breast cancer cell apoptosis. CONCLUSION AR signaling suppresses TRAIL-induced breast cancer cell apoptosis, in part, by suppressing DR5 expression, and a combination of AR antagonists together with TRAIL may be a novel and effective therapy for TNBC.
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BACKGROUND AND OBJECTIVES: Chronic impairment of beta-adrenergic receptor signaling increases cardiac apoptosis, hypertrophy and fibrosis. The aim of this study was to investigate whether isoproterenol (ISO), an agonist of the adrenergic receptor, can enhance tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human embryonic kidney (HEK) 293 cells. MATERIALS AND METHODS: HEK 293 cells were treated with ISO and/or TRAIL for 24 hours. Cell viability was evaluated by microscopy and an established viability assay, and apoptotic cell death was analyzed by staining with fluorescein isothiocynate-annexin-V/propidium iodide (PI) and caspase activation. To confirm the mechanism of cell death induced by co-treatment with ISO and TRAIL, expression of TRAIL receptor 2 (death receptor 5, DR5) was evaluated by immunoblotting. RESULTS: Although ISO or TRAIL treatment decreased HEK 293 cell viability by 13% and 17%, respectively, co-treatment with ISO and TRAIL resulted in a markedly higher death rate of 35% after 24 hours. Increases were evident in early apoptotic cells (i.e., annexin-V positive/PI negative; 19.4%), late apoptotic cells (i.e., annexin-V positive/PI positive; 6.3%) and dead cells (i.e., annexin-V negative/PI positive; 1.1%) when cells were co-treated with ISO and TRAIL, compared to cells treated with either ISO or TRAIL. In addition, marked increases of cleaved cas-3, cleaved poly (adenosine diphosphate-ribose) polymerase and DR5 were observed in HEK 293 cells co-treated with ISO and TRAIL. CONCLUSION: Treatments combining ISO with TRAIL may be responsible for death of HEK 293 cells through DR5 up-regulation. Activation of adrenergic receptors is responsible for the synergistic cell death observed with TRAIL.
Subject(s)
Humans , Apoptosis , Cell Death , Cell Survival , Fibrosis , Fluorescein , HEK293 Cells , Hypertrophy , Immunoblotting , Isoproterenol , Kidney , Microscopy , Mortality , Necrosis , Receptors, Adrenergic , Receptors, TNF-Related Apoptosis-Inducing Ligand , TNF-Related Apoptosis-Inducing Ligand , Up-RegulationABSTRACT
Objective: To observe the apoptosis-inducing effect of recombinant mutant human tumor necrosis factor-related apoptosis-inducing ligand (rmhTRAIL): on human lung cancer cell line A549 and to identify the different protein expression profiles related to apoptosis. Methods: After the A549 cells were treated with rmhTRAIL, the proliferation viability was assessed by MTT assay, and the cell cycle and apoptosis were analyzed by flow cytometry. Then the liquid chromatograph-tandem mass spectrometer (LC-MS/MS): was used to detect the different expression profiles related to apoptosis. Finally, real-time fluorescence quantitative PCR (RFQ-PCR): and Western blotting were performed to identify the expression levels of apoptosis-related genes. Results: After A549 cells were treated with different concentrations of rmhTRAIL for 24 h, the inhibitory rates of proliferation were significantly increased in a concentration-dependent manner (all P < 0.05). The half maximal inhibitory concentration was (9.5±3.9): ×105 ng/mL. The early apoptosis rate was significantly increased after 5×105 ng/mL rmhTRAIL treatment for 24 h (P < 0.01). However, rmhTRAIL had no effect on cell cycle. After treatment with rmhTRAIL, the expressions of tumor necrosis factor receptor superfamily (TNFRSF): members 1 OB and 1 OD were down-regulated by 21.3% and 31.8%, respectively; and the expression of cellular FLICE-inhibitory protein (c-FLIP): was up-regulated by 2.867 times. Both RFQ-PCR and Western blotting analysis indicated that the expression of death receptor 5 (DR5), one of TNFRSF members, was down-regulated in both mRNA and protein levels (both P < 0.05). Relatively, the expression of c-FLIP was up-regulated in both mRNA and protein levels (both P < 0.05). Conclusion: rmhTRAIL can induce apoptosis of human lung cancer A549 cells, and this mechanism is associated with the down-regulation of DR5 expression and up-regulation of c-FLIP expression.
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Objective To deterine the expression of TNF-related apoptosis inducing ligand (TRAIL) and its receptor DR5 in murine myocardium with acute viral myocarditis(VM).Methods We builted the model of VM.Eight mice of the VM group and the normal control group were sacrificed on the 7th,10th,14th,21st,28th day after inoculation CVB3 virus.The myocardial histopathological scores were counted.The terminal reansferase-mediated dUPT-biotin nick end-labeling (TUNEL) assays was used to quantified apoptosis rate.The expression of TRAIL and DR5 protein and mRNA were determined by the method of immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR).Results The expression of TRAIL and DR5 protein and mRNA were found in myocardium of both the normal control group and the VM group.The expression of TRAIL protein of the VM group(14th) were significantly higher than which in the normal group at the same time and the VM group(7th)(F=9.17,P<0.01).The DR5 protein of the VM group(10th,14th,21st)were significantly higher than which in the normal group at the same time and the VM group(7th)(F=13.32,P<0.01).The expression of TRAIL and DR5 protein were positive correlated with the myocardial histopathological scores and the apoptosis rate.The expression of TRAIL mRNA of the VM group(10th) were significantly higher than which in the normal group at the same time and the VM group(7th)(F=10.86,P<0.01).The DR5 mRNA of the VM group(10th,14th)were significantly higher than which in the normal group at the same time and the VM group(7th)(F=22.75,P<0.01).Conclusion High characteristic expressions of protein/mRNA TRAIL and DR5 were observed in the myocardium of mice with VM.The level was positive correlationed with the account of pathology and the rate of apoptosis.The apoptosis induced by TRAIL and DR5 may participate in the pathophysiological processes of VM.
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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.
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Objective To explore the effect of TNF related apoptosis inducing ligand (TRAIL) in apoptosis induced by LPS. Methods After LPS injected mice blocking TRAIL with soluble death receptor 5 (sDRS), detecting ALT, AST and LDH of mice serum at different times, apoptotic effects of LPS to mice hepatocyte were detected by HE and flow eytometry (FCM) with Annexin V-FITC/PI staining. The expres-sion of DR5 in mice hepatocyte was assayed with immunohistochemistry and FCM. Results Apoptotic effect was promoted by up-regulated DR5 expression on hepatocyte. Blocking TRAIL with sDR5 markedly amelio-rated the hepatocyte damage and reduced apoptosis. Conclusion These results establish a critical role for TRAIL in apoptosis during disease process of LPS.
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Objective: To construct the expressing vector of the extracellular domain of death receptor 5 (DR5), express it E.coli, identify the purified DR5 protein, and study its biological activity. Methods: The extracellular domain of DR5(eDR5) was assembled by overlapping PCR. The expression vector pET-22b(+)/ DR5 was constructed and transformed into E.coli BL21(DE3). The expression of eDR5 protein was induced by IPTG and purified by Ni 2+ -affinity chromatographic column. The purity and specificities were detected by SDS-PAGE and ELISA, respectively. The blocking effects of purified eDR5 on FMU1.5-induced apoptosis of U343, U373 cells were observed. Results: The extracellular domain of DR5 was obtained by overlapping PCR. The eDR5 protein was expressed in both supernatants and inclusion bodies with a yield more than 30% of total bacterial proteins. The purity of eDR5 was more than 95% and the yield reached 9 mg/ml. The result of ELISA showed the purified protein was eDR5. Purified eDR5 partially blocked the apoptosis of U343 cells induced by FMU1.5 and TRAIL. Conclusion: The successful construction, expression, and purification of the extracellular domain of DR5 protein lays a foundation for further study of DR5 function.
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Objective:To observe anti-DR5 monoclonal antibody on apoptosis and CDC effect in EC109 cells.Methods:The anti-DR5 monoclonal antibody was prepared by hybridoma technique.Tumoricidal effects and complement-dependent cytotoxicity of the McAb to EC109 cells was screened by MTT assay.The apoptosis of EC109 cells was detected by flow cytometry with annexin Ⅴ-FITC/PI staining.Morphological change of EC109 was observed by microphotograph.Results:An anti-DR5 monoclonal antibody was obtained.It induced apoptosis of EC109 dose dependently.The cytotoxic action was notably enhanced by addition of complement.The cells growth inhibition ratios reached 83.04%.The apoptotic body and cathepsis were seen in microphotograph.Conclusion:The anti-DR5 monoclonal antibody could induce EC109 cells apoptosis and cause the complement dependent cytotoxic (CDC) effects powerfully.
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Objective:To study the role of DR5 in TRAIL apoptotic signal transduction. Methods:BALB/C mice were immunized with recombinant DR5 that contains the full-length extracellular domain of the human DR5. Anti-DR5 mAb was generated by hybridoma. The level of DR5 expression on Jurkat cell line was examined by flow cytometry. The rates of TRAIL-induced apoptosis and anti-DR5 mAb blocking on Jurkat cells were tested by flow cytometry with TRAIL apoptosis kit.Results:The percentage of DR5 expression on Jurkat cells was 94 83%. TRAIL and anti-TRAIL mAb could kill Jurkat cells on dose-dependent, and the killing rate was 90% in the concentration of 50～100 ng/ml. The killing role of TRAIL could be blocked on Jurkat cells pretreated with anti-DR5 mAb. The average percentage of blocking was 90 49%.Conclusion:DR5 plays a very key role in TRAIL induced apoptosis in Jurkat cells.