Effect of DR4 Demethylation to the Proliferation and Apoptosis of Myeloid Leukemia K562 Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of tumor necrosis factor death receptor (DR) 4 demethylation to the proliferation and apoptosis of myeloid leukemia K562 cells.@*METHODS@#The logarithmic phase of K562 cells were treated by desitabine (DCA) at 0, 0.8, 1.6 and 3.2 μmol/L, and the cells were divided into control group, DCA low dose group, DCA medium dose group and DCA high dose group respectively. The cells in control group were treated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) 0.5 μg/ml for 24 h, and the cells were divided into TRAIL group. The cells in DCA high dose group were treated by TRAIL 0.5 μg/ml for 24 h, and were divided into DCA high dose + TRAIL group. Methylation-specific polymerase chain reaction (MS-PCR) was used to measure the methylation status of the DR4 gene promoter in the control group and DCA low, medium and high dose groups. Real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) and Western blot were used to determine the relative expression of DR4 mRNA and protein in the control group and DCA low, medium and high dose groups. Dime- thylthiazole (MTT) method was used to determine the inhibition rate of cell proliferation of the cells in control group, DCA high dose group, TRAIL group, DCA high dose + TRAIL group. Flow cytometry was used to determine the apoptotic rate of the cells in control group, DCA high dose group, TRAIL group, DCA high dose + TRAIL group.@*RESULTS@#The cells in the control group were methylation-positive, the brightness of the methylation bands of the cells in the DCA low, medium, and high dose groups was gradually decreased to disappear, and the DCA high dose group showed negative for methylation. The relative expression of DR4 mRNA and protein in the control group, DCA low, medium and high dose groups was increased sequentially (r=0.624, 0.704). The inhibition rate of cell proliferation of the cells in the control group, DCA high dose group, TRAIL group, DCA high dose + TRAIL group was increased sequentially (r=0.653, 0.754, 0.709, 0.725) at 24, 48 and 72 h.@*CONCLUSION@#DCA can reverse the methylation level of DR4 gene promoter in ML K562 cells and up-regulate the expression of DR4, which may enhance the proliferation inhibition and apoptosis promotion effects of TRAIL on K562 cells.

Influence of LBP alone or Combined with TRAIL on Apoptosis of MLL Rearranged Leukemic Cells / 中国实验血液学杂志

OBJECTIVE@#To investigate the effect of lycium barbarum polysaccharide (LBP) alone or combined with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the apoptosis of leukemia cell lines with MLL gene-rearrangement, and to explore the cell apoptotic pathway after the combined action.@*METHODS@#MLL-ALL cell line KOCL44 and KOCL45 were selected as the research object, then the control and experimental groups were set up. The cell survival rate was measured by the trypan blue dye exclusion method, the cell early apoptosis and expression of death receptors on the cell surface were detected by flow cytometry with Annexin-V/PI double staining. The protein level of caspase-8, BID, caspase-3, caspase-9, BAD, BCL-2, as well as mitochondrial and cytosol Cyto-C were detected by Western blot.@*RESULTS@#LBF combined with TRAIL inhibited the growth of KOCL44 and KOCL-45 cells and showed the synergistic effect, the results of flow cytometry with Amnexiu V/PI double staining were consistent with above-mentioned results. After treatment of KOCL44 and KOCL45 cells with LBF plus TRAIL, the significant expression of DR4 on cell surface was not found, while the expression of DR4 receptor was enhanced significantly, the pro-apoptotic proteins including caspase-8, BID, caspase-3, caspase-9 and BAD were activated significantly and BCL-2 was suppressed significantly with time-dependent manner. The expression of mitochondria cyto-C in KOCL44 and KOCL45 decreased along with prolonging of treatment time (r=-0.95, r=-0.866), while the expression of cytosol cyto-C in KOCL44 and KOCL45 increased along with prolonging of treatment time (r=0.883, r=0.903).@*CONCLUSION@#The combination of LBP and TRAIL significantly increases the apoptosis of KOCL44 and KOCL45, and the LBP and TRAIL can up-regulate the expression of TRAIL death receptor-DR5 on the cell surface, activate the pathway of caspase and mito-chrondia mitachondria, thus enhance the sensitivity of KOCL44 and KOCL45 to TRAIL induced apoptosis through both mitochondrial and apoptotic pathway.

Ursodeoxycholic Acid Induces Death Receptor-mediated Apoptosis in Prostate Cancer Cells

BACKGROUND: Bile acids have anti-cancer properties in a certain types of cancers. We determined anticancer activity and its underlying molecular mechanism of ursodeoxycholic acid (UDCA) in human DU145 prostate cancer cells. METHODS: Cell viability was measured with an MTT assay. UDCA-induced apoptosis was determined with flow cytometric analysis. The expression levels of apoptosis-related signaling proteins were examined with Western blotting. RESULTS: UDCA treatment significantly inhibited cell growth of DU145 in a dose-dependent manner. It induced cellular shrinkage and cytoplasmic blebs and accumulated the cells with sub-G1 DNA contents. Moreover, UDCA activated caspase 8, suggesting that UDCA-induced apoptosis is associated with extrinsic pathway. Consistent to this finding, UDCA increased the expressions of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor, death receptor 4 (DR4) and death receptor 5 (DR5), and TRAIL augmented the UDCA-induced cell death in DU145 cells. In addition, UDCA also increased the expressions of Bax and cytochrome c and decreased the expression of Bcl-xL in DU145 cells. This finding suggests that UDCA-induced apoptosis may be involved in intrinsic pathway. CONCLUSIONS: UDCA induces apoptosis via extrinsic pathway as well as intrinsic pathway in DU145 prostate cancer cells. UDCA may be a promising anti-cancer agent against prostate cancer.

Isoproterenol Enhances Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand-Induced Apoptosis in Human Embryonic Kidney Cells through Death Receptor 5 up-Regulation

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.

Associations of Crohn's disease with DR4 and DR5 gene polymorphisms / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To assess the associations of death receptor DR4 and DR5 gene polymorphisms with Crohn's disease (CD).</p><p><b>METHODS</b>A total of 295 CD patients and 490 healthy controls were recruited. Three single nucleotide polymorphisms (SNPs) of the DR4 (rs13278062, rs20575) and DR5 (rs1047266) genes were determined with a SNaPshot method. Unconditional logistic regression analysis was carried out for determining the allelic and genotypic differences of the three SNPs between CD patients and the controls, as well as the influence of the DR4 and DR5 gene polymorphisms on the clinical features of CD patients. Linkage disequilibrium and haplotype analysis were calculated by haplotype 4.2 and R language software. A gene-gene interaction model was established to analyze whether the three SNPs can exert a synergistic effect on the susceptibility to CD.</p><p><b>RESULTS</b>The mutant allele (T) and genotype (GT+TT) of DR4 (rs13278062) were increased among CD patients compared to the controls (37.12% vs. 32.04%, P = 0.040, 95%CI: 1.010-1.550; 62.71% vs. 54.90%, P = 0.032, 95%CI: 1.028-1.855, respectively). However, the allelic and genotypic frequencies of DR4 (rs20575) and DR5 (rs1047266) did not differ between the two groups (all P > 0.05). Based on the Montreal Classification Standards, the CD patients were stratified by locations and behaviors of the disease. After multiple comparison correction (P < 0.0125), compared to ileocolonic CD patients respectively, the mutant allele (T) and genotype (GT+TT) of the rs13278062 polymorphism were significantly increased in colonic CD patients (41.04% vs. 25.64%, P = 0.002, 95%CI: 0.315-0.778; 66.04% vs. 41.03%, P = 0.001, 95%CI: 0.196-0.655, respectively) and terminal ileum CD patients (41.44% vs. 25.64%, P = 0.002, 95%CI: 0.311-0.762; 74.77% vs. 41.03%, P < 0.001, 95%CI: 0.126-0.437, respectively). In comparison to penetrating CD patients, the mutant allele (T) and genotype (GT+TT) of DR4 (rs13278062) were significantly decreased in stricturing CD patients (32.29% vs. 48.91%, P = 0.007, 95%CI: 0.300-0.828; 57.29% vs. 86.96%, P = 0.001, 95%CI: 0.078-0.520, respectively). A similar conclusion was drawn for the mutant genotype (GT+TT) of DR4 (rs13278062) in non-stricturing, non-penetrating CD patients (58.82% vs. 86.96%, P = 0.001, 95%CI: 0.086-0.536). Haplotype analysis indicated that the CT haplotype formed by rs20575 and rs13278062 was increased in CD patients compared to the controls (37.1% vs. 31.8%, P = 0.029, OR=1.279, 95%CI: 1.022-1.600). The outcome of a gene-gene interaction model indicated that the mutant genotype (GT+TT) of DR4 (rs13278062) and mutant genotype (CT+TT) of DR5 (rs1047266) may play a negatively synergistic role in CD patients (B = - 0.483, OR = 0.617, P = 0.030).</p><p><b>CONCLUSION</b>The rs13278062 polymorphism of the DR4 gene not only can confer an increased risk for CD, but may also influence the location of the lesions and the disease behaviors. The CT haplotype formed by rs20575 and rs13278062 may be an independent risk factor for CD. Furthermore, the mutant genotype (GT+TT) of DR4 (rs13278062) and mutant genotype (CT+TT) of DR5 (rs1047266) may exert a negative synergistic effect on CD.</p>

Detection of anticancer and apoptotic effect of the produced IgYs against the three extracellular domain of human DR5 protein

TNF alpha cytokine family in the body plays divers' roles in the cellular events such as cell proliferation, differentiation, necrosis, septic shock and apoptosis. In response to TNF therapy, several cell signaling pathways activated in cells which in different manners can lead to apoptosis or necrosis. However induction of apoptosis is depended on one of its important members, TRAIL and its receptors that will be followed by apoptosis activity. Tumor necrosis factor-related apoptosis-inducing ligand [TRAIL] and especially the DR5, is generating considerable interests as a possible anticancer therapeutic agent because of its selective activation in apoptosis of this receptor as a superior affinity to ligands. The study was performed in invitro assay and the anticancer effects of the produced antibodies were assumed by MTT and flowcytometric methods. In the first step for immunization of the hens, three selective small peptides from extracellular domain of DR5 which were chemically synthesized, injected to hens and after the proper immunization of them, IgYs were extracted from the egg yolk. After assumption of specificity of the purified IgYs against the whole DR5 protein, they were performed in MTT assay and flowcytometric colorimeter. After confirmation of synthesized peptides they were injected to hens with Fround`s complete adjuvant. With completing the immunization procedure the specificity of purified IgYs were confirmed by ELISA. The antibodies were significantly killed the MCF7 breast cancer cells, but had divers affect [proliferative] on normal hepatocyte cells. Additionally, significantly they induced apoptosis on the cancerous cells in contrast to control cells. The results clearly demonstrated that the produced IgYs with reduced cost and time managing could remarkably use as an effective anticancer drug

Role of TRAIL in the treatment of prostate cancer: An update / 中华男科学杂志

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF super family found in recent years, which widely exists in the body tissues and participates in the immune regulation, immune stability, and immune surveillance of the human body. The TRAIL receptor is expressed in the surface of a variety of cells. Recent studies show that TRAIL induces the apoptosis of tumor cells and has no significant toxic effect on normal cells. Its anti-tumor activity and safety have been widely recognized. The development of prostate cancer is regulated by the mechanisms of cell apoptosis. TRAIL can induce the apoptosis of prostate cancer cells, and therefore has a great application value in the treatment of prostate cancer.

Molecular mechanism of cisplatin to enhance the ability of TRAIL in reversing multidrug resistance in gastric cancer cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To study the molecular mechanism of cisplatin to enhance the ability of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in reversing multidrug resistance in vincristine-resistant human gastric cancer SGC7901/VCR cells.</p><p><b>METHODS</b>MTT assay was used to measure the 50% inhibiting concentration (IC₅₀) and cell survival in SGC7901 and SGC7901/VCR cells after different treatments. SGC7901/VCR cells were treated with different concentrations of DDP, different concentrations of TRAIL alone or in combination, and then the mRNA and protein levels of several genes were determined by RT-PCR, RT-qPCR and Western-blot analysis. After targeted silencing with specific siRNA and transfection of recombinant plasmid c-myc into the SGC7901/VCR cells, the mRNA and protein levels of DR4, DR5 and c-myc were determined by RT-PCR and Western-blot analysis.</p><p><b>RESULTS</b>After combined treatment with TRAIL and DDP of the SGC7901/VCR cells, the IC₅₀ of VCR, DDP, ADM, and 5-Fu treatment was significantly decreased compared with the control group or TRAIL-treated group (P < 0.05). After treatment with 0, 10, 50 ng/ml TRAIL in combination with 0.4 µg/ml DDP, the SGC7901/VCR cells showed significantly higher activation of caspase 3, down-regulation of DNA-PKcs/Akt/GSK-3β signaling pathway, and higher inhibition of MDR1(P-gp) and MRP1 than those treated with TRAIL alone (P < 0.01 for all). The mRNA and protein levels of DR4, DR5, c-myc were significantly decreased after silencing c-myc with specific siRNA in the SGC7901/VCR cells (P < 0.01 for all), and were significantly increased after transfection of recombinant plasmid c-myc into the SGC7901/VCR cells (P < 0.01 foe all). After the treatment with 10 ng/ml TRAIL, 0.25 µg/ml DDP + 10 ng/ml TRAIL and 0.5 µg/ml DDP + 10 ng/ml TRAIL, the relative expression level of c-myc protein in the SGC7901/VCR cells was 0.314 ± 0.012, 0.735 ± 0.026, and 0.876 ± 0.028, respectively, and the relative expression of cytochrome C was 0.339 ± 0.036, 0.593 ± 0.020 and 0.735 ± 0.031, respectively, and the relative expression levels of DR4, DR5, active-caspase 3 and active-caspase 9 in the SGC7901/VCR cells were also increased along with increasing DDP concentrations.</p><p><b>CONCLUSIONS</b>The activation of DNA-PKcs/Akt/GSK-3β signaling pathway and high expression of MDR1 and MRP1 play an important role in the multi-drug resistance properties of SGC7901/VCR cells. After combining with TRAIL, DDP can enhance the expression of DR4 and DR5 through up-regulating c-myc and enhancing the activation of caspase 3 and caspase 9 by facilitating mitochondrial release of cytochrome C. It may be an important molecular mechanism of DDP-induced sensitization of TRAIL to reverse the multidrug resistancein SGC7901/VCR cells.</p>

The synergism and mechanism of action of rClone30-hDR5 in combination with TRAIL on HCC / 药学学报

To investigate the cell-killing effect and its possible mechanism of rClone30-hDR5 in combination with TRAIL on human hepatic carcinoma (HCC) cell line, first of all, recombinant plasmid pee12.4-hDR5 was introduced into HepG2 cells by liposome transfection. After five rounds of screening by flow cytometry, HepG2 cells expressing high levels of DR5 on cell surface were isolated. The cytotoxicity of TRAIL to selected cells was higher than that of TRAIL to HepG2 cells by MTT method (P < 0.01). The result suggested that the cloned hDR5 gene had biological activity. MTT assay showed that, rClone30- hDR5 in combination with TRAIL more efficiently inhibited the tumor growth of HepG2 cells compared to rClone30-hDR5 or TRAIL in vitro. The results of Annexin V-FITC/PI staining and Quantitative Real-time PCR indicated that rClone30-hDR5 in combination with TRAIL significantly increased the mRNA levels of caspase 3 and caspase 8, and induced the apoptosis of tumor cells. HepG2 cells were infected with rClone30-hDR5 or rClone30 at MOI of 1. The expression of hDR5 on tumor surface increased significantly by rClone30-hDR5 compared to that by rClone30, which contributed to the sensitivity to TRAIL. In conclusion, rClone30-hDR5 in combination with TRAIL has potential application value in cancer treatment.

Induction of apoptosis by a hexane extract of aged black garlic in the human leukemic U937 cells

BACKGROUND/OBJECTIVES: In this study, the apoptogenic activity and mechanisms of cell death induced by hexane extract of aged black garlic (HEABG) were investigated in human leukemic U937 cells. MATERIALS/METHODS: Cytotoxicity was evaluated by MTT (3-(4, 5-dimethyl-thiazol-2-yl)-2, 5-diphenyl tetrazoliumbromide) assay. Apoptosis was detected using 4,6-diamidino-2-phenyllindile (DAPI) staining, agarose gel electrophoresis and flow cytometry. The protein levels were determined by Western blot analysis. Caspase activity was measured using a colorimetric assay. RESULTS: Exposure to HEABG was found to result in a concentration- and time-dependent growth inhibition by induction of apoptosis, which was associated with an up-regulation of death receptor 4 and Fas legend, and an increase in the ratio of Bax/Bcl-2 protein expression. Apoptosis-inducing concentrations of HEABG induced the activation of caspase-9, an initiator caspase of the mitochodrial mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly(ADP-ribose)-polymerase. HEABG also induced apoptosis via a death receptor mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid, and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. However, pre-treatment of U937 cells with the caspase-3 inhibitor, z-DEVD-fmk, significantly blocked the HEABG-induced apoptosis of these cells, and increased the survival rate of HEABG-treated cells, confirming that HEABG-induced apoptosis is mediated through activation of caspase cascade. CONCLUSIONS: Based on the overall results, we suggest that HEABG reduces leukemic cell growth by inducing caspase-dependent apoptosis through both intrinsic and extrinsic pathways, implying its potential therapeutic value in the treatment of leukemia.

Enhanced sensitivity of leukemia cell line KG-1a to activated immune cell-mediated cytolysis after treated with resveratrol / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the enhanced sensitivity of leukemia cell line KG-1a to activated immune cell-mediated cytolysis after treated with resveratrol.</p><p><b>METHODS</b>The value of 50% inhibition concentration (IC₅₀) for KG-1a by resveratrol was analyzed using trypan blue staining. Peripheral blood mononuclear cells were separated, and then activated by interleukin (IL)-2 and IL-15. The sensitivity of KG-1a treated with and without resveratrol to activated immune cell-mediated cytolysis was assayed by lactate dehydrogenase (LDH) -releasing assay. The expression of tumor necrosis factor related apoptosis inducing ligand (TRAIL) on the surface of activated immune cells and its receptors (DR4/5 and DcR1/2) on the surface of KG-1a were detected by flow cytometry.</p><p><b>RESULTS</b>Resveratrol could inhibit the proliferation of KG-1a and IC50 at 24 h was 25 mmol/L. At a ratio of 10:1 or 20:1 between effect and target, the cytolytic rates of treated KG-1a by activated immune cells were (55.80 ± 10.88)% and (72.31 ± 13.06)%, significantly higher than (24.96 ± 9.25)% and (37.93 ± 5.21)% of untreated KG-1a (P<0.05). The expression of DR5 on the surface of KG-1a treated with resveratrol was (9.05 ± 3.57)%, significantly higher than (3.11 ± 0.54)% of untreated KG-1a (P<0.05). Conversely, the expression of DcR1 on the surface of treated KG-1a was (13.23 ± 3.56)%, lower than (53.75 ± 10.51)% of KG-1a (P<0.05). When TRAIL pathway on the surface of activated immune cells was blocked, the cytolytic rates of treated KG-1a were (35.97 ± 6.36)% and (49.80 ± 10.68)%, significantly lower than (52.92 ± 6.98)% and (70.73 ± 9.79)% of untreated KG-1a (P<0.05) at the same ratio of effector and target.</p><p><b>CONCLUSION</b>Resveratrol could enhance cytolytic sensitivity of KG-1a by activated immune cells through TRAIL pathway.</p>

Hypobaric hypoxia increases the expression of death receptor 5 and inhibits that of FLICE-like inhibitory protein in the rat testis / 中华男科学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of hypobaric hypoxia on the expressions of death receptor 5 (DR5) and cellular FLICE-like inhibitory protein (c-FLIP) and the distribution of c-FLIP in the rat testis.</p><p><b>METHODS</b>Forty adult male SD rats were randomly divided into four groups of equal number: normoxia control, 3 d hypoxia, 15 d hypoxia and 30 d hypoxia. The control rats were raised at 300 m above the sea level, while the latter three groups of rats in a hypobaric chamber at a simulated altitude of 4000 m for 5, 15 and 30 days, respectively. Then the expressions of DR5 and c-FLIP were detected by immunoblotting and the distribution of c-FLIP in the testis observed by immunofluorescence.</p><p><b>RESULTS</b>The expressions of DR5 were 2.04 +/- 0.11, 1.97 +/- 0.12 and 2.34 +/- 0.11 in the 3 d, 15 d and 30 d hypoxia groups, respectively, significantly higher than 1.78 +/- 0.09 in the normoxia group (P < 0.05). The expressions of c-FLIP were 0.87 +/- 0.03 and 0.74 +/- 0.07 in the 15 d and 30 d hypoxia groups, respectively, significantly lower than 1.03 +/- 0.02 in the normoxia group (P < 0.05).</p><p><b>CONCLUSION</b>Simulated hypobaric hypoxia at 4000 m above the sea level increased the expression of DR5 and inhibited that of c-FLIP in the rat testis.</p>

Casticin induces caspase-mediated apoptosis via activation of mitochondrial pathway and upregulation of DR5 in human lung cancer cells

OBJECTIVE@#To assess if casticin induces caspase-mediated apoptosis via activation of mitochondrial pathway and upregulation of DR5 in human lung cancer cells.@*METHODS@#Human non-small-cell lung carcinoma cell lines H460, A549 and H157 were cultured in vitro. The cytotoxic activities were determined using MTT assay. The apoptotic cells death was examined by flow cytometry using PI staining and DNA agarose gel electrophoresis. The activities of caspase-3, -8 and -9 were measured via ELISA. Cellular fractionation was determined by flow cytometry to assess release of cytochrome c and the mitochondrial transmembrane potential. Bcl-2/Bcl-XL/XIAP/Bid/DR5 and DR4 proteins were analyzed using western blot.@*RESULTS@#The concentrations required for a 50% decrease in cell growth (IC(50)) ranged from 1.8 to 3.2 μM. Casticin induced rapid apoptosis and triggered a series of effects associated with apoptosis by way of mitochondrial pathway, including the depolarization of the mitochondrial membrane, release of cytochrome c from mitochondria, activation of procaspase-9 and -3, and increase of DNA fragments. Moreover, the pan caspase inhibitor zVAD-FMK and the caspase-3 inhibitor zDEVD-FMK suppressed casticin-induced apoptosis. In addition, casticin induced XIAP and Bcl-XL down-regulation, Bax upregulation and Bid clearage. In H157 cell line, casticin increased expression of DR5 at protein levels but not affect the expression of DR4. The pretreatment with DR5/Fc chimera protein effectively attenuated casticin-induced apoptosis in H157 cells. No correlation was found between cell sensitivity to casticin and that to p53 status, suggesting that casticin induce a p53-independent apoptosis.@*CONCLUSIONS@#Our results demonstrate that casticin induces caspase-mediated apoptosis via activation of mitochondrial pathway and upregulation of DR5 in human lung cancer cells.

Effect of doxorubicin on TRAIL resistance and TRAIL receptor expression in lymphoma cell line SNK-6 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of doxorubicin on TRAIL resistance and TRAIL receptor expression in lymphoma cell line SNK-6 cells.</p><p><b>METHODS</b>SNK-6 cells treated with doxorubicin at different concentrations alone or in combination with tumor necrosis factor related apoptosis inducing ligand (TRAIL). Cell proliferation was evaluated by MTT assay. Apoptosis and the expression of TRAIL receptors were determined by flow cytometry.</p><p><b>RESULTS</b>MTT assay showed that treatment with 100 and 1000 ng/ml doxorubicin for 24 h, the survival rates of SNK-6 cells were (80.9 ± 7.2)% and (53.7 ± 2.8)%, significantly higher than that by treatment combined with 500 ng/ml TRAIL (64.9 ± 1.1)% and (34.0 ± 3.9)%, respectively (P < 0.05). Flow cytometry showed that after treatment with 100 and 1000 ng/ml doxorubicin for 48 h, the survival rates of SNK-6 cells were (69.9 ± 6.1)% and (31.1 ± 1.9)%, while treated in combination with 500 ng/ml TRAIL, the cell survival rates were (37.5 ± 6.4)% and (15.0 ± 1.8)%, respectively. The early apoptosis rate was (14.8 ± 0.6)% and (30.8 ± 1.5)%, significantly lower than that [(28.7 ± 0.6)% and (46.6 ± 2.8)%] after treatment in combination with TRAIL (P < 0.05). The expressions of TRAIL receptors and decoy receptors were increased when SNK-6 cells were treated with 100 ng/ml doxorubicin for 24 hours.</p><p><b>CONCLUSIONS</b>Doxorubicin can overcome to a certain extent the TRAIL resistance of SNK-6 cells and induce upregulation of TRAIL death receptors and decoy receptors on the surface of SNK-6 cells. However, a higher dose is needed.</p>

Detection of the expression of NK ligands in acute leukemia cell lines by real-time PCR / 中华血液学杂志

<p><b>OBJECTIVE</b>To detect the expression profile of NK ligands in acute leukemia cell lines and investigate the differential expression pattern between acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML).</p><p><b>METHODS</b>Using quantitative real-time PCR, 23 NK ligands (MICA, MICB, ULBP-1, ULBP-2, ULBP-3, ULBP-4, HLA-E, HLA-G, CD48, NBTA, HLA-F, LLT-1, PVR, Nectin2, CD72, CD80, ICAM-1, LFA-3, CRACC, Fas, DR4, DR5, TNFR1) were detected in 6 acute leukemia cell lines, including 3 ALL cell lines (CEM, Jurkat T, Reh) and 3 AML cell lines (HL-60, KG-1a, NB4), respectively. Independent-samples t test analysis was performed to determine statistical significance.</p><p><b>RESULTS</b>Using β-actin as reference gene, the relative expression results showed that the expression of 4 NK ligands between ALL and AML is significantly different. Specifically, the level of ULBP-2 is higher in ALL (CEM: 1, Jurkat T: 0.617, Reh: 0.246) than that in AML (HL-60: 0.000, KG-1a: 0.003, NB4: 0.000)(P = 0.047). However, the expressions of CD48, PVR(PVR-1, PVR-2) and DR4 is higher in AML (HL-60: 13.987, 4.403, 10.334, 8.711; KG-1a: 5.387, 2.900, 7.315, 4.512; NB4: 7.763, 3.248, 7.049, 6.127) than that in ALL (CEM: 1, 1, 1, 1; Jurkat T: 2.035, 1.553, 3.888, 0.449; Reh: 1.559, 0.000, 0.000, 1.304) (P = 0.044, 0.014, 0.014, 0.011). And there're no significant differences between the rest 19 NK ligands.</p><p><b>CONCLUSIONS</b>ULBP-2, CD48, PVR and DR4 might play an important role in the distinct mechanisms in leukemogenesis between ALL and AML and could be potential targets for diagnosis and treatment.</p>

Glycosylation inhibitor 2-deoxy-D-glucose sensitizes oral cancer cells to TRAIL-induced apoptosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of 2-deoxy-D-glucose (2-DG) in enhancing the sensitivity of oral cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis.</p><p><b>METHODS</b>The oral cancer cell line KB was incubated in the presence of different concentrations (0, 0.625, 1.25, 2.5, 5, and 10 mmol/L) of 2-DG with or without TRAIL (200 ng/ml). The cell viability was measured using MTT assay and cell apoptosis was detected using flow cytometry with propidium iodide (PI) staining. KB cells treated with 5 mmol/L 2-DG with or without TRAIL for 0, 6, 16, or 24 h were examined with Western blotting for protein expressions of death receptor 5 (DR5) and caspase-3.</p><p><b>RESULTS</b>Treatment of the cells with 5 mmol/L 2-DG for 24, 48 and 72 h resulted in a cell viability of 25.25%, 69.06%, and 59.19%, respectively. Combined treatment with 5 mmol/L 2-DG with TRAIL for 24 significantly enhanced the cell apoptotic rate (72.5%) as compared to the rate induced by TRAIL alone (45.3%) and by 2-DG (15.9%) alone. 2-DG treatment markedly up-regulated DR5 and caspase-3 expression and enhanced the inhibitory effect of TRAIL on cell colony formation.</p><p><b>CONCLUSION</b>2-DG sensitizes oral cancer cells to TRAIL- induced apoptosis by up-regulating DR5 and caspase-3 expressions.</p>

The Synergistic Apoptotic Interaction of Indole-3-Carbinol and Genistein with TRAIL on Endometrial Cancer Cells

Induction of apoptosis in target cells is a key mechanism by which chemotherapy promotes cell killing. The purpose of this study was to determine whether Indole-3-Carbinol (I3C) and Genistein in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induce apoptosis in endometrial cancer cell (Ishikawa) and to assess apoptotic mechanism. The MTT assay and flow cytometry were performed to determine cell viability and cell cycle. The induction of apoptosis was measured by caspase-3 activity test, DNA fragmentation assay, annexin V binding assay and western blot analysis. There was no effect in cell growth inhibition and cell cycle progression alone or in two-combination. However, the treatment of I3C and Genistein followed by TRAIL showed significant cell death and marked increase in sub-G1 arrest. Three-combination treatment revealed elevated expression of DR4, DR5 and cleaved forms of caspase-3, caspase-8, PARP. The Flip was found down regulated. Moreover, increase in caspase-3 activity and DNA fragmentation indicated the induction of apoptosis. The results indicate that I3C and Genistein with TRAIL synergistically induced apoptosis via death receptor dependent pathway. Our findings might provide a new insight into the development of novel combination therapies against endometrial cancer.

Down-Regulation of Survivin by Nemadipine-A Sensitizes Cancer Cells to TRAIL-Induced Apoptosis

The tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the tumor necrosis factor family of cytokines. TRAIL selectively induces apoptotic cell death in various tumors and cancer cells, but it has little or no toxicity in normal cells. Agonism of TRAIL receptors has been considered to be a valuable cancer-therapeutic strategy. However, more than 85% of primary tumors are resistant to TRAIL, emphasizing the importance of investigating how to overcome TRAIL resistance. In this report, we have found that nemadipine-A, a cell-permeable L-type calcium channel inhibitor, sensitizes TRAIL-resistant cancer cells to this ligand. Combination treatments using TRAIL with nemadipine-A synergistically induced both the caspase cascade and apoptotic cell death, which were blocked by a pan caspase inhibitor (zVAD) but not by autophagy or a necrosis inhibitor. We further found that nemadipine-A, either alone or in combination with TRAIL, notably reduced the expression of survivin, an inhibitor of the apoptosis protein (IAP) family of proteins. Depletion of survivin by small RNA interference (siRNA) resulted in increased cell death and caspase activation by TRAIL treatment. These results suggest that nemadipine-A potentiates TRAIL-induced apoptosis by down-regulation of survivin expression in TRAIL resistant cells. Thus, combination of TRAIL with nemadipine-A may serve a new therapeutic scheme for the treatment of TRAIL resistant cancer cells, suggesting that a detailed study of this combination would be useful.

Synergistic interactions of TRAIL and paclitaxel on the nasopharyngeal carcinoma cell lines in vitro / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To investigate the synergistic cytotoxicity of TRAIL and paclitaxel on nasopharyngeal cell lines CNE-1 and CNE-2.@*METHOD@#CCK-8 assays the growth inhibition rate of CNE-1 and CNE-2 which was treated with TRAIL or paclitaxel or combination of both. Flow cytometry tests the apoptosis rate of CNE-1 and CNE-2 which was treated with TRAIL or paclitaxel or combination of each other.@*RESULT@#In certain range of time and concentration,TRAIL and paclitaxel inhibited the growth of the cell lines of CNE-1 and CNE-2 in a time-dose dependent manner (P < 0.05). The rate of growth inhibition and apoptosis in TRAIL and paclitaxel combinative group was more significant than that in the TRAIL and paclitaxel singular group (P < 0.05).@*CONCLUSION@#TRAIL and paclitaxel had a synergistic killing effect on NPC cell lines and showed better affection than singular group, which provides a novel and prospective strategy for NPC chemotherapy.

Induction of apoptosis in human Hep3B hepatoma cells by norcantharidin through a p53 independent pathway via TRAIL/DR5 signal transduction / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the inhibitory activities of norcantharidin (NCTD), a demethylated analogue of cantharidin, on Hep3B cells (a human hepatoma cell line) with deficiency of p53.</p><p><b>METHODS</b>The survival rate of the Hep3B cells after treating with NCTD was measured by MTT assay. Cell cycle of treated cells was analyzed by flow cytometry, and DNA fragmentation was observed by electrophoresis. The influence of inhibitors for various caspases and anti-death receptors antibodies on the NCTD-induced apoptosis in the cells was determined.</p><p><b>RESULTS</b>NCTD treatment resulted in growth inhibition of Hep3B cells in a dose- and time-dependent manner. Cell cycle analysis of the cells after treatment with NCTD for 48 h shows that NCTD induced G(2)M phase arrest occurs at low concentration ([Symbol: see text] 25 μmol/L) but G(0)G(1) phase arrest at high concentration (50 μmol/L). The addition of both caspase-3 and caspase-10 inhibitors completely inhibited DNA fragmentation. Addition of anti-TRAIL/DR5 antibody significantly inhibited DNA fragmentation.</p><p><b>CONCLUSION</b>NCTD may inhibit the proliferation of Hep3B cells by arresting cell cycle at G(2)M or G(0)G(1) phase, and induce cells apoptosis via TRAIL/DR5 signal transduction through activation of caspase-3 and caspase-10 by a p53-independent pathway.</p>