IFNγ联合TRAIL诱导神经母细胞瘤细胞凋亡的研究

目的探讨IENγ（γ干扰素）对TRAIL（肿瘤坏死因子相关凋亡诱导配体）诱导神经母细胞瘤细胞株SMS-KCNR（KCNR）细胞凋亡的影响及其发生机制。方法应用RT-PCR方法检测IFNγ作用前后KCNR细胞Caspase8的表达；应用四甲基偶氮唑蓝（MTT）比色法及流式细胞仪（FCM）检测IFNγ、TRAIL、IFNγ＋TRAIL及IFNγ＋Caspase8抑制剂（zIETD-FMK）＋TRAIL对KCNR细胞生长及凋亡的影响；应用比色法测定Caspase8相对活性。结果KCNR细胞不表达Caspase8，IFNγ作用48h后的KCNR细胞Caspase8表达明显增加；KCNR细胞对TRAIL不敏感，IFNγ诱导表达Caspase8的KCNR细胞对TRAIL敏感；IFNγ＋TRAIL组Caspase8相对活性明显高于TRAIL组及抑制剂组；zIETD-FMK能阻断Caspase8的活化而抑制TRAIL对KCNR细胞的诱导凋亡作用。结论IFNγ通过诱导Caspase8表达而逆转KCNR细胞对TRAIL诱导凋亡的耐受。     

MYCN基因表达抑制促TRAIL诱导神经母细胞瘤细胞凋亡的研究

目的神经母细胞瘤(NB)为小儿常见恶性肿瘤。MYCN基因高扩增NB细胞对TRAIL诱导凋亡多有抵抗。我们以MYCN基因高扩增NB细胞株为研究对象,抑制其MYCN基因的表达,探讨其对TRAIL诱导凋亡有无增强作用。方法构建MYCN siRNA,转染NB细胞株SK-N-BE(2),抑制MYCN基因表达后,Western-blot法检测SK-N-BE(2)细胞Bcl-2、Bcl-xL、Bid、DR4、DR5表达的变化,ELISA法检测细胞凋亡。结果转染MYCN siRNA的SK-N-BE(2)细胞中MY-CN基因表达显著降低(P<0.05)。MYCN基因表达抑制后,SK-N-BE(2)细胞DR5、Bid表达增高(P<0.05),Bcl-2、Bcl-xL表达降低(P<0.05),DR4表达无变化(P>0.05),TRAIL诱导细胞凋亡显著增强(P<0.05)。结论 MYCN基因表达抑制后,可调控Bcl家族中相关蛋白、DR5的表达,促进TRAIL诱导NB细胞凋亡。     

Caspase-8在TRAIL诱导神经母细胞瘤细胞凋亡中的作用

目的：应用干扰素(IFNγ)诱导神经母细胞瘤（neuroblastoma, NB）细胞caspase 8的表达并观察其是否可以恢复NB细胞对肿瘤坏死因子相关凋亡诱导配体（TRAIL）的敏感性。方法：应用RT PCR方法检测IFNγ作用前后NB细胞caspase-8 mRNA的表达;应用Alamar Blue法及流式细胞术检测IFNγ、TRAIL、IFNγ+TRAIL、IFNγ+caspase-8抑制剂zIETD-FMK+TRAIL对NB细胞生长及凋亡的影响;应用比色法测定NB细胞caspase-8相对活性。结果：对TRAIL敏感的CHP212细胞表达caspase-8,且经IFNγ处理后caspase-8 表达水平逐步增加;对TRAIL不敏感的SY5Y细胞不表达caspase-8,IFNγ作用后其caspase-8 mRNA表达明显增加。IFNγ与TRAIL联用对SY5Y细胞有明显诱导凋亡作用。CHP212细胞caspase-8相对活性随TRAIL作用时间的延长逐步升高;IFNγ与TRAIL联合作用的SY5Y细胞caspase-8相对活性明显高于未加药物处理的对照组、IFNγ组、TRAIL组及抑制剂组。结论：表达caspase-8的NB细胞对TRAIL的诱导凋亡作用敏感,TRAIL诱导NB细胞凋亡过程中伴随caspase-8活性的增加。［中国当代儿科杂志,2010,12(11)：902-907］     

5-氮杂胞苷增强阿霉素对神经母细胞瘤细胞的抗瘤活性

目的：许多神经母细胞瘤细胞系及肿瘤组织标本中caspase-8表达缺失, caspase-8基因沉寂的主要原因是其启动子区域高度甲基化。该文探讨去甲基化药物5-氮杂胞苷对caspase-8表达及对化疗药阿霉素抗人神经母细胞瘤细胞作用的影响及其影响机制。方法：应用RT-PCR方法检测5-氮杂胞苷作用前后SH-SY5Y细胞中caspase-8 mRNＡ水平变化。MTT分析研究5-氮杂胞苷与化疗药阿霉素联合应用前后人神经母细胞瘤细胞SH-SY5Y的存活率,以及加入caspase-8活性抑制剂后存活率的变化。结果：RT-PCR方法发现SH-SY5Y细胞株不表达caspase-8 mRNA, 5-氮杂胞苷作用3 d后可检测到 caspase-8 mRNA表达,5 d后表达较第3天增加; 5-氮杂胞苷与不同浓度阿霉素(0.05, 0.1, 0.25, 0.5 μg/mL)联合应用后SH-SY5Y细胞存活率为(77.61±7.30)%,（57.35±6.64）%,（46.25±4.46）%,（35.59±5.12）%,同一浓度单独应用阿霉素组细胞存活率为（94.89±4.15）%,（80.60±8.50）%,（64.48±4.92）%,（52.32±6.71）%,5-氮杂胞苷与阿霉素联用组细胞存活率明显低于单用阿霉素组,差异均有显著性。Caspase-8抑制剂组与同一浓度的5-氮杂胞苷+阿霉素组比较,细胞存活率明显增加,依次为（92.95±3.48）%,（78.39±4.28）%,（62.31±6.50）%,（49.92±5.77）%,差异均有显著性。结论：阿霉素对神经母细胞瘤细胞SH-SY5Y具有增殖抑制作用,5-氮杂胞苷可以增强阿霉素的抗瘤活性。其发生机制可能是通过上调caspase-8 mRNA的表达而实现的。［中国当代儿科杂志,2007,9（6）：577-579］     

皮肤血管瘤患儿肿瘤坏死因子相关凋亡诱导配体及死亡受体的表达与细胞凋亡的关系

目的探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)及其死亡受体4、5(DR4、DR5)在小儿皮肤血管瘤各阶段的表达及其与细胞凋亡的关系。方法采用免疫组织化学法检测增生期、消退期血管瘤和正常皮肤组织中TRAIL和DR4、DR5蛋白的表达,并采用末端脱氧核苷酸转移酶介导的末端标记技术(TUNEL法)检测各组织细胞凋亡情况。结果TRAIL、DR4、DR5蛋白的阳性表达率及细胞凋亡指数(AI)在血管瘤消退期明显高于血管瘤增生期和正常皮肤组织(P<0.05)。结论血管瘤的各个阶段均存在细胞凋亡现象,在由增生期转变为消退期的过程中出现细胞凋亡的上调,TRAIL及DR4、DR5参与细胞凋亡的调节,其与血管瘤的自行消退过程有关。     

三氧化二砷对人神经母细胞瘤细胞凋亡作用的影响

目的：三氧化二砷(As2O3 )通过诱导细胞凋亡和诱导细胞分化效应治疗急性早幼粒细胞白血病(APL)患者已取得很好疗效。与APL细胞相似,神经母细胞瘤(NB)细胞也是分化成熟受阻,该文对As2O3 在体外对人神经母细胞瘤细胞凋亡作用的影响及可能的机制进行探讨。方法：比色法观察As2O3 对神经母细胞瘤SK N SH细胞增殖的影响;Giemsa染色观察细胞形态学改变;Annexinⅴ/PI双染色流式细胞术检测细胞凋亡;免疫细胞化学染色方法检测bcl 2蛋白表达变化。结果：As2O3 明显抑制SK N SH细胞增殖,抑制作用呈剂量时间依赖效应,并出现细胞凋亡的形态学改变;流式细胞仪检测4. 0μmol/LAs2O3 作用SK N SH细胞72h后,早期凋亡细胞比例( 9. 9±0. 8 )%,与对照组( 3. 7±0. 2 )%相比明显增多,差异有显著性(P< 0. 05 );分别以1. 0, 2. 0,4. 0μmol/L的As2O3 处理SK N SH细胞72h后,bcl 2表达随As2O3 浓度增加呈降低趋势,bcl 2表达阳性率分别为(26. 3±8. 0)%, (15. 0±4. 5)%和(4. 8±3. 2)%,与对照组(73. 6±6. 1)%相比,差异有显著性(P<0. 01)。结论：As2O3 可在体外抑制神经母细胞瘤细胞增殖,诱导凋亡,bcl 2参与了其调节作用。     

TRAIL蛋白联合顺铂抑制裸鼠横纹肌肉瘤生长的实验研究

目的 探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)蛋白及联合顺铂对RD人横纹肌肉瘤裸鼠移植瘤生长的影响及其可能的作用机制.方法 将RD人横纹肌肉瘤细胞制成细胞悬液后接种于裸鼠皮下,成瘤后将裸鼠随机分4组:生理盐水组、TRAIL组、顺铂组及两药联合组.检测裸鼠的重量和体积;测定裸鼠肝功能、尿素氮及肌酐;另取肝肾组织进行切片,HE染色观察;用FCM方法检测肿瘤组织Fas表达;用RT-PCR检测DR4和DR5mRNA的表达.结果 各组裸鼠实验前后的体重变化无明显差异;DDP组和TRAIL+DDP组裸鼠的血清丙氨酸转氨酶高于生理盐水组,DDP组与TRAIL+DDP组裸鼠尿素氮和肌酐值比较,无明显差异;TRAIL组、DDP组和TRAIL+DDP组移植瘤的重量均明显降低;各组肝肾组织切片观察未见明显改变;TRAIL+DDP组Fas表达水平高于DDP组和TRAIL组;DDP组和TRAIL+DDP组裸鼠移植瘤细胞的DR5mRNA、DR4mRNA表达水平明显升高,而TRAIL组没有明显改变.结论 TRAIL和顺铂对裸鼠移植瘤的生长有抑制作用,联用有协同作用.     

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目的探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)对人神经母细胞瘤的作用及干扰素-γ(IFN-γ)对新型凋亡分子TRAIL抗瘤活性的影响,并探讨其影响机制。方法应用MTT分析和流式细胞仪研究TRAIL对人神经母细胞瘤细胞的抑制作用及IFN-γ对TRAIL抗瘤活性的影响。用RT-PCR方法检测IFN-γ作用48h后,Caspase-8-mRNA的表达。结果TRAIL(10,50,100μg/L)单独作用、IFN-γ(1000U/mL)单独作用后,对SY5Y细胞的增殖抑制率分别为(4·38±0·89)%、(3·54±1·66)%、(5·03±1·26)%、(5·33±2·06)%;凋亡率分別为(5·18±3·33)%、(5·26±3·64)%、(5·00±2·88)%、(8·14±7·35)%。IFN-γ(1000U/mL)与TRAIL(100μg/L)联合作用后,对SY5Y细胞的增殖抑制率为(41·22±7·09)%;凋亡率为(21·29±6·20)%。RT-PCR方法发现IFN-γ作用48h后Caspase-8-mRNA的表达明显上调。结论神经母细胞瘤细胞SH-SY5Y对TRAIL不敏感,IFN-γ可以明显提高TRAIL对神经母细胞瘤细胞的敏感性,其发生机制可能是通过IFN-γ上调Caspase-8-mRNA的表达而实现的。     

死亡受体4和5在颅咽管瘤中的表达

目的研究肿瘤坏死因子相关凋亡诱导配体(TRAIL)的死亡受体(DR)4和DR5在颅咽管瘤细胞中的表达,探讨其临床意义。方法联合采用免疫组织化学和原位杂交方法检测颅咽管瘤28例和正常脑组织25例中DR表达。观察原位杂交前后颅咽管瘤和正常脑组织中DR表达差异性。结果免疫组织化学染色显示,颅咽管瘤28例均大量表达DR4和DR5,而正常脑组织25例中表达DR4 10例(40.0%),表达DR5 8例(32.0%)。颅咽管瘤组织DR蛋白高表达不同于正常脑组织DR蛋白低表达,两者差异有显著性(P<0.01)。原位杂交显示,DR在28例颅咽管瘤组织和大部分正常脑组织中均呈强阳性表达,两者差异无显著性(P>0.05)。结论颅咽管瘤细胞中普遍存在DR高表达,这可能为颅咽管瘤的凋亡诱导治疗提供新靶点。DR蛋白在正常脑组织和颅咽管瘤中的表达差异可能是TRAIL选择性诱导凋亡的机制之一。     

γ干扰素与阿霉素联用对成神经细胞瘤细胞生长及凋亡的影响

目的探讨γ干扰素(IFN-γ)对阿霉素抗人成神经细胞瘤细胞作用的影响,并探讨其影响机制。方法应用四甲基偶氮唑蓝(MTT)分析和流式细胞仪,研究IFN-γ与化疗药阿霉素联合应用前后人成神经细胞瘤细胞SH-SY5Y的存活率及凋亡率;免疫组化方法检测IFN-γ作用前后半胱氨酸蛋白酶-8(caspase-8)蛋白的表达。结果阿霉素(0.03,0.10,0.30μg/ml)单独作用24h后,SY5Y细胞的存活率分别为(95.62±13.03)%,(82.62±7.94)%和(64.84±9.19)%,各组间差异显著。IFN-γ(10,100,1000U/ml)单独作用48h后,SY5Y细胞的存活率分别为(98.37±11.25)%,(97.15±5.36)%和(98.84±7.41)%,各组间差异无显著性。IFN-γ(1000U/ml)与不同浓度的阿霉素(0.03,0.10,0.30μg/ml)联合作用后,SY5Y细胞的存活率同单独应用阿霉素组比较明显下降,差异有显著性;阿霉素(0.30μg/ml)单独作用24h,SH-SY5Y的凋亡率为(22.00±6.55)%,IFN-γ(1000U/ml)单独作用48h,凋亡率为(8.22.±4.00)%。二者联合作用后,凋亡率较单用阿霉素组比较明显升高,差异有显著性;免疫组化方法发现SH-SY5Y细胞株不表达caspase-8,IFN-γ作用48h后caspase-8表达阳性。结论阿霉素对成神经细胞瘤细胞SH-SY5Y具有抑制增殖和诱导凋亡的作用,IFN-γ可以使其作用明显增强。其发生机制可能是通过IFN-γ上调caspase-8蛋白的表达而实现的。     

Resistance to TRAIL-induced apoptosis in neuroblastoma cells correlates with a loss of caspase-8 expression

BACKGROUND: Disruption of apoptotic pathways may be involved in tumor formation, regression, and treatment resistance of neuroblastoma (NB). TNF-related apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in cancer cell lines. PROCEDURE: In this study we analyzed the expression and function of TRAIL, its agonistic and antagonistic receptors, and important intracellular signaling elements in 18 NB cell lines. RESULTS: Semiquantitative RT-PCR revealed that TRAIL-R2 and TRAIL-R3 are the main TRAIL-receptors used by NB cells. Sensitivity to TRAIL-induced apoptosis did not correlate with mRNA expression of TRAIL receptors or cFLIP. Surprisingly, caspase-8 and caspase-10 mRNA was detected in only 5 of 18 NB cell lines. Interestingly, only these five NB cell lines were susceptible to TRAIL-induced apoptosis in a time- and dose-dependent manner. CONCLUSIONS: Treatment with 5-aza-2'-deoxycytidine restored mRNA expression of caspase-8 and -10 and TRAIL sensitivity of resistant cell lines, suggesting that gene methylation is involved in caspase inactivation. Since many cytotoxic drugs induce caspase-dependent apoptosis, failure to express caspase-8 and/or caspase-10 might be an important mechanism of resistance to chemotherapy in NB.     

ROLE OF CASPASE 8 AS A DETERMINANT IN TRAIL SENSITIVITY OF NEUROBLASTOMA CELL LINES

Objective: Resistance of neuroblastoma (NB) cells to tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis is thought to be caused by loss of caspase 8 expression. The aim of this study is to investigate if induction of caspase 8 by γ-interferon (IFNγ) renders NB cells sensitive to TRAIL. Methods: Caspase 8 expression was monitored by RT-PCR and Western blot analysis. The effects of IFNγ, TRAIL, IFNγ + TRAIL, and caspase 8 inhibitor + TRAIL on the growth and apoptosis of NB cells were detected with the methods of reduction rate of Alamar blue assay and flow cytometry. The relative caspase 8 activity was measured with colorimetric assay. Results: An increased expression of caspase 8 mRNA and protein was found after treatment with IFNγ. IFNγ in combination with TRAIL decreased proliferation of NB cell line SH-SY5Y cells. The killing effect of TRAIL on NB cells expressing caspase 8 was depressed by caspase 8 inhibitor. The relative caspase 8 activity of NB cells expressing caspase 8 increased with the prolongation of TRAIL action time. Conclusions: TRAIL induced apoptosis in NB cells expressing caspase 8.     

Loss of caspase-8 expression in neuroblastoma is related to malignancy and resistance to TRAIL-induced apoptosis

Background and Procedures NB-derived cell lines were tested for their sensitivity to apoptosis induced by the tumor-selective apoptotic ligand TRAIL. Noninvasive S-type cell lines are highly sensitive to TRAIL, whereas invasive N-type cell lines are resistant. RESULTS: Although both S- and N-type cell lines express TRAIL-R2, FADD, and caspases-3 and -10, only S-type cells express caspase-8. Reduced levels of caspase-8 protein were also observed in a stage IV NB tumor when compared to a ganglioneuroma. The caspase-8 gene is not deleted in either N-type NB cell lines or high-stage tumors, and expression can be induced by demethylation. CONCLUSIONS: Therefore, caspase-8 expression is silenced in malignant NB, which correlates to tumor severity and resistance to TRAIL-induced apoptosis.     

Enhanced effect of IFNgamma on the induced apoptosis of neuroblastoma cells by cytotoxic drugs

The objective of this study was to explore the antitumor effects of cytotoxic drugs combined with IFNgamma on neuroblastoma cell line SH-SY5Y cells. The expression of caspase 8 mRNA and protein was detected with RT-PCR and Western blot analysis. The effects of cytotoxic drugs and IFNgamma combined with cytotoxic drugs on the growth and apoptosis of SH-SY5Y cells were detected with the methods of MTT and flow cytometry. Caspase 8 activity was measured by colorimetric assay. Caspase 8 was undetectable in SH-SY5Y cells with an increased expression of caspase 8 after the treatment of IFNgamma. SH-SY5Y cells were sensitive to Adriamycin relatively but resistant to TNFalpha and TRAIL, while IFNgamma-pretreated SH-SY5Y cells were more sensitive to the cytotoxic drugs with an increase of caspase 8 activity. The authors conclude that IFNgamma can sensitize SH-SY5Y cells to Adriamycin-, TNFalpha-, and TRAIL-induced apoptosis and this may be realized by the upregulation of caspase 8.     

TRAIL/Apo2L ligands induce apoptosis in malignant rhabdoid tumor cell lines

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a potent inducer of apoptosis in various cancer cells, whereas normal cells are not sensitive to TRAIL-mediated apoptosis. Four TRAIL/Apo2L receptors (DR4, DR5, DcR1, and DcR2) have been identified. DR4 and DR5 have a death domain, whereas DcR1 and DcR2 are called decoy receptors because of their incomplete or lack of a death domain. Malignant rhabdoid tumor (MRT) is an aggressive neoplasm showing a poor prognosis because of its resistance to chemotherapeutic agents. In this study, we examined whether TRAIL could induce apoptotic cell death in MRT cell lines. We found that although half of the MRT cell lines examined were sensitive to TRAIL/Apo2L, Western blot analysis revealed that the expression of DcR2 was low in TRAIL-sensitive MRT cells. We examined the effect of doxorubicin on the expression levels of TRAIL receptors and its enhancement on the susceptibility of MRT cell lines to TRAIL. Western blot and flow cytometric analyses revealed that doxorubicin significantly increased the expression of DR5, and somewhat up-regulated the expression of DR4 and DcR2. Moreover, doxorubicin, NF-kappaB inhibitor (SN50), and PI3-kinase/Akt inhibitor (wortmannin, LY294002) enhanced the susceptibility of MRT cell lines to TRAIL/Apo2L-induced apoptosis. These results suggest that TRAIL/Apo2L may provide the basis for clinical trials of TRAIL-based treatment to improve the outcome of MRT patients.     

TRAIL及其受体DR5在病毒性心肌炎小鼠心肌组织中的表达和意义

目的 研究肿瘤坏死因子相关的凋亡诱导配体(TRAIL)及其死亡受体5(DR5)在病毒性心肌炎小鼠心肌组织中病变不同时期的表达及与细胞凋亡的关系.方法 建立病毒性心肌炎小鼠模型,于注射病毒后第7、10、14、21、28天取心肌组织,HE染色做心肌病理积分,TUNEL法检测凋亡细胞百分率,免疫组织化学法和逆转录-聚合酶链反应(RT-PCR)检测心肌组织中TRAIL和DR5蛋白及mRNA的表达.结果 病毒感染组小鼠和正常对照组小鼠心肌组织中均存在TRAIL和DR5蛋白和mRNA的表达.病毒感染后第14天,病毒感染组小鼠心肌组织中TRAIL蛋白表达高于同期正常对照组(P<0.05)和第7天病毒感染组(P<0.05),组间比较差异有统计学意义(F=9.17,P<0.01).病毒感染后第10、14、21天,病毒感染组小鼠DR5蛋白表达高于同期正常对照组(P<0.01)和第7天病毒感染组(P<0.01),组间比较差异有统计学意义(F=13.32,P<0.01).且TRAIL和DR5蛋白的表达与心肌病理积分、心肌细胞凋亡率密切相关(P<0.05).病毒感染组第10天TRAIL mRNA表达高于同期正常对照组(P<0.01)和第7天病毒感染组(P<0.01),组间比较差异有统计学意义(F=10.86,P<0.01).病毒感染组第10、14天DR5 mRNA表达高于同期正常对照组(P<0.01)和第7天病毒感染组(P<0.01),组间比较差异有统计学意义(F=22.75,P<0.01).结论 病毒性心肌炎小鼠发病中期,TRAIL及其受体DR5在心肌组织中出现高表达,且与病理积分、心肌细胞凋亡率成正相关,TRAIL及其受体DR5可能通过调控心肌细胞凋亡参与病毒性心肌炎的病理过程.