绒毛中TRAIL及其受体的表达与不明原因反复自然流产的相关性的探讨

目的探讨肿瘤坏死因子相关凋亡诱导配体TRAIL及其受体在不明原因早期反复自然流产患者(URSA)绒毛中的表达及二者的相关性。方法选择实验组妊娠45～60 d的URSA患者15例,对照组健康人工流产15例。两组分别取绒毛组织采用免疫组化法检测TRAIL及其受体的表达,进行方差分析和t检验比较两组绒毛组织中TRAIL及其受体蛋白表达水平的差异。结果实验组绒毛组织中TRAIL及其受体DR4、DR5蛋白表达较强,而诱骗受体DcR1及DcR2蛋白与正常对照相比表达较少,P值均小于0.05。结论TRAIL及其受体可能是造成自然流产的机制之一。     

慢性乙肝患者外周血单个核细胞TRAIL受体表达及其临床意义

目的探索慢性乙肝患者外周血单个核细胞(PBMC)肿瘤细胞坏死因子相关的凋亡诱导配体(TRAIL)受体在PBMC凋亡中的作用,及其与机体肝脏损伤的相关性。方法用RT-PCR和流式细胞术检测55例慢性乙肝患者(包括轻度、中度、重度)外周血单个核细胞TRAIL各受体(DR4、DR5、DcR1和DcR2)表达水平,同时检测肝功能相关指标,并进行相关性分析。以30例正常人作为对照。结果诱骗受体DcR1在慢性乙肝患者中的表达显著低于对照组(P<0.05)。DcR1的表达随慢性乙肝病情的加重而逐渐降低。慢性乙肝患者的DcR1表达与转氨酶(ALT)呈显著负相关,与血清白蛋白成显著正相关。结论慢性乙肝患者外周血单个核细胞DcR1表达下调可能是其细胞凋亡增加的机制之一,且DcR1表达情况可从一定程度上反映肝脏的损伤程度。     

重组人可溶性TRAIL分子诱导白血病细胞株凋亡的研究

比较重组人可溶性TRAIL(rhsTRAIL)诱导Jurkat细胞株、K562细胞株以及HL-60细胞株凋亡之间的差异,探讨这些差异与细胞表面TRAIL受体(DR4、DR5、DcR1和DcR2)表达量的关系。不同浓度的rhsTRAIL分别处理Jurkat细胞、K562细胞和HL-60细胞12 h、24 h和48 h后,用流式细胞仪检测经碘化丙啶(PI)染色后的细胞凋亡情况;用RT-PCR方法检测细胞表面受体DR4、DR5、DcR1、DcR2的表达。培养12 h、24 h、48 h后,不同浓度rhsTRAIL诱导Jurkat细胞株的凋亡率均明显高于对照组,且具有剂量依赖性和时间依赖性;但K562细胞株和HL-60细胞株未见明显的凋亡发生。RT-PCR结果显示,培养12 h、24 h、48 h后,Jurkat细胞株表面DR4的表达随时间的延长和rhsTRAIL浓度的升高而升高,而DR5、DcR1和DcR2的表达未检出;K562和HL-60细胞株表面DR4的表达没有明显变化,而且DR5、DcR1和DcR2的表达也未检出。rhsTRAIL诱导Jurkat细胞株的凋亡具有剂量依赖性和时间依赖性,且与其细胞表面DR4的表达呈正相关;在一定的浓度条件下,rhsTRAIL未能诱导K 562和HL-60细胞株发生明显凋亡,且其细胞表面DR4的表达也未见明显变化。这些结果提示,应用TRAIL治疗不同种类白血病时,应注意它的使用剂量和适应范围。     

TRAIL及其受体的研究进展

TNF相关的凋亡诱导配体(TNF-related apoptosis inducing ligand，TRAIL)是最近发现的TNF家族的新成员，与Apo-1L(FasL)有较高的同源性。TRAIL有两类受体，一类是死亡受体，诱导肿瘤细胞或转化细胞凋亡；另一类是“诱骗”受体，保护正常细胞免遭TRAIL的诱导凋亡作用。TRA几及其受体的发现为肿瘤的治疗提供了一个新的方向。     

杭白菊增强TRAIL基因诱导大肠癌细胞凋亡及机制的实验研究

目的：探讨杭白菊提取液对肿瘤坏死因子相关凋亡诱导配体基因（TRAIL）抑制人大肠癌细胞株DLD-1作用的影响及其可能机制。 方法： 杭白菊提取液联合重组腺病毒载体（Ad）介导的TRAIL基因作用于人大肠癌细胞株DLD-1，通过倒置显微镜、MTT比色法和流式细胞仪，研究分析其对DLD-1细胞抑制作用的效果。采用逆转录聚合酶链反应（RT-PCR）和流式细胞术检测杭白菊提取液作用前后DLD-1细胞TRAIL、TRAIL受体（TRAIL-Rs）mRNA以及细胞表面TRAIL蛋白表达的变化。 结果： Ad/hTERT-gTRAIL对DLD-1细胞的生长抑制率和凋亡率分别为31.4%和13.5%；联合杭白菊提取液后，生长抑制率和凋亡率均显著提高，达93.1%和45.4%（P<0.05）。杭白菊提取液作用后DLD-1细胞TRAIL mRNA的表达量从作用前的0.46上调至1.01, 细胞表面TRAIL蛋白表达的百分率从作用前的2.2%升高到5.0%（P<0.05）。TRAIL死亡受体（DR4、DR5）mRNA的表达量分别从0.70和0.22上调至1.10和0.83（P<0.05），而TRAIL诱骗受体（DcR1、DcR2）mRNA的表达量从0.60和1.15下调至0.19和0.78（P<0.05）。 结论： 杭白菊提取液联合重组腺病毒载体（Ad）介导的TRAIL基因(Ad/hTERT-gTRAIL)能有效诱导DLD-1细胞的凋亡。杭白菊提取液上调TRAIL死亡受体表达以及下调TRAIL诱骗受体的表达可能在增强TRAIL诱导的凋亡作用中起着重要作用。     

TRAIL及其受体的研究进展

TNF相关的凋亡诱导配体 (TNF relatedapoptosisinducingligand ,TRAIL)是最近发现的TNF家族的新成员 ,与Apo 1L(FasL)有较高的同源性。TRAIL有两类受体 ,一类是死亡受体 ,诱导肿瘤细胞或转化细胞凋亡 ;另一类是“诱骗”受体 ,保护正常细胞免遭TRAIL的诱导凋亡作用。TRAIL及其受体的发现为肿瘤的治疗提供了一个新的方向。     

077 TRAIL及其受体的研究进展

TNF相关的凋亡诱导配体(TNF-related apoptosis inducing ligand,TRAIL))是最近发现的TNF家族的新成员,与Apo-1 L(FasL)有较高的同源性.TRAIL有两类受体,一类是死亡受体,诱导肿瘤细胞或转化细胞凋亡;另一类是"诱骗"受体,保护正常细胞免遭TRAIL的诱导凋亡作用.TRAIL及其受体的发现为肿瘤的治疗提供了一个新的方向.     

白藜芦醇增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用

目的:观察白藜芦醇作用前后TRAIL对人髓系白血病KG-1a细胞的细胞毒作用的变化。方法:流式细胞仪检测KG-1a细胞表面CD34和CD38的表达,二甲氧唑黄(XTT)细胞增殖及细胞毒性检测试剂盒检测白藜芦醇作用前后TRAIL对KG-1a细胞增殖的影响,AnnexinV-FITC/PI染色流式细胞仪检测细胞凋亡变化。流式细胞仪检测白藜芦醇作用前后KG-1a细胞表面TRAIL死亡受体表达变化。结果:人髓系白血病KG-1a细胞CD34+CD38-占(58.67±2.87)%,10~1 000 ng/ml的TRAIL对KG-1a细胞增殖无明显影响,但对白藜芦醇作用后的KG-1a细胞的增殖有明显抑制作用,白藜芦醇能促进TRAIL诱导KG-1a细胞凋亡,并能上调KG-1a细胞表面TRAIL死亡受体DR5的表达。结论:白藜芦醇能增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用,其机制可能与白藜芦醇上调KG-1a细胞表面TRAIL死亡受体DR5的表达有关。     

肿瘤坏死因子相关凋亡诱导配体在多种疾病中的生物学作用

肿瘤坏死因子相关凋亡诱导配体（Apo2L/TRAIL）是肿瘤坏死因子家族的一员,可以诱导表达特异性死亡受体TRAIL-R1 （DR4）或TRAIL-R2 （DR5）的细胞凋亡.TRAIL可诱导多种肿瘤细胞凋亡,对正常细胞无杀伤性,因此将其作为抗肿瘤靶向治疗候选药物之一,备受关注.近期研究发现,TRAIL既通过其受体介导细胞凋亡信号通路,又可传导非凋亡的信号通路,在自身免疫病和感染性疾病中发挥重要生物学作用.因而简单阐明TRAIL在人类多种疾病中生物学作用的研究进展,对今后TRAIL研究方向和治疗策略的选择具有指导意义.     

细胞对TRAIL诱导凋亡敏感性的调控机制

TRAIL作为一种新发现的细胞凋亡诱导分子,可诱导多种肿瘤细胞发生凋亡,而对正常细胞无明显毒性作用。TRAIL还可与化、放疗协同作用,逆转肿瘤细胞对药物、放射线的耐受性,使其凋亡率明显增加,因而TRAIL在难治性肿瘤的治疗中具有良好的应用前景。然而,并非所有肿瘤细胞都对TRAIL敏感。细胞对TRAIL诱导凋亡的敏感性,是多种内源性因素共同作用的结果,本文从诱骗受体、NF—κB、c—FLIP、IAPs与Smac／DIABLO、bcl-2蛋白家族等几个方面综述了国内外近年来对TRAIL敏感性影响因素的研究进展。     

Progression in melanoma is associated with decreased expression of death receptors for tumor necrosis factor-related apoptosis-inducing ligand

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in melanoma by interaction with death receptors TRAIL-R1 (DR4) or TRAIL-R2 (DR5) on melanoma cells or resists apoptosis by interaction with decoy receptors TRAIL-R3 (DcR1) or TRAIL-R4 (DcR2). Studies on cell lines suggest that there is a wide variation in TRAIL death receptor expression; however, their expression on excised human melanoma is not well documented. In view of this, we studied death receptor expression on melanomas using monoclonal antibodies specific for these receptors. Immunohistochemical staining for DR4, DR5, and DcR1/DcR2 was performed on formalin-fixed paraffin-embedded sections of 100 cases of primary melanoma, metastatic melanoma, and benign nevi. Percentage expressions of DR4 versus DR5 in benign nevi, primary melanoma, and melanoma metastases were 40% versus 90%, 69% versus 98%, and 55% versus 66%, respectively. There were significant differences in the mean percentage of DR5-positive cells between different groups of melanocytic lesions. Percent expression was higher in thin (< or =1.0 mm) compared with thick primary melanoma (88.9% versus 66.9%), and expression was less in subcutaneous metastases (49%) and lymph node metastases (30.6%) (P < .005). Expression was also higher in compound nevi (57%) than dysplastic nevi (49%). DcR1/DcR2 was found in 75% of benign nevi, 62% of primary melanomas, and 74% melanoma metastases. The results showed a wide variation in the expression of death receptors for TRAIL between and within primary and metastatic melanoma and a decreased expression on the thick primary melanoma and metastatic melanoma. This suggests that melanoma may not respond to treatment with TRAIL unless given with agents that increase the expression of TRAIL death receptors.     

Expression of TRAIL (TNF-related apoptosis-inducing ligand) and its receptors in normal colonic mucosa,adenomas, and carcinomas

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in tumour cell lines. Four membrane-bound receptors for TRAIL have been identified, two apoptosis-mediating receptors, DR4 and DR5, and two apoptosis-inhibiting receptors, DcR1 and DcR2. The aim of this study was to examine the role of TRAIL and its receptors in colorectal cancer development. The immunohistochemical expression and localization of TRAIL and its receptors were investigated in normal mucosa (n=10), adenomas (n=19), and carcinomas (n=21). Correlations between the expression of TRAIL and its receptors and the degree of apoptosis (assessed by M30 expression) and histopathological characteristics were explored. TRAIL and its receptors were expressed in normal mucosal epithelium. Expression of the receptors was seen in adenomas and carcinomas. TRAIL expression was lost in a subset of colorectal tumours, more frequently in carcinomas than in adenomas (p<0.05). DR4 and DR5 staining was stronger in neoplastic cells than in normal cells and was accompanied by a higher degree of apoptosis. No differences were found between tumour and normal cells regarding DcR1 and DcR2 expression. No correlations were found between TRAIL or TRAIL receptor expression and histopathological characteristics. In conclusion, marked changes were seen in the course of the adenoma-carcinoma sequence with respect to the expression of TRAIL and TRAIL receptors DR4 and DR5. The stronger expression of DR4 and DR5 in neoplastic cells than in normal cells, together with a higher degree of apoptosis, suggests a possible functional role for these receptors in apoptosis induction in neoplastic colorectal cells.     

Application of flow cytometry to molecular medicine: detection of tumor necrosis factor-related apoptosis-inducing ligand receptors in acute myeloid leukaemia blasts

TRAIL (tumor necrosis factor-related apoptosis-inducing ligand), a cytokine belonging to the TNF (tumor necrosis factor) family, is currently regarded as a potential anti-cancer agent. Nevertheless, several types of cancer cells display a low sensitivity to TRAIL or are completely resistant to this pro-apoptotic cytokine. TRAIL signalling is dependent on four receptors. Two of them, death receptors 4 and 5 (DR4 and DR5), induce apoptosis, whereas decoy receptors 1 and 2 (DcR1 and DcR2) are unable to evoke cell death upon TRAIL binding. TRAIL resistance may be related to the expression of TRAIL decoy receptors. TRAIL has been proposed as a novel therapeutic agent for the treatment of haematological disorders, including acute myeloid leukaemia (AML). Surprisingly, however, very limited information is available concerning the expression of TRAIL receptors in AML blasts. Here, we have evaluated, using flow cytometry, TRAIL receptor surface expression and sensitivity to TRAIL-dependent apoptosis of AML blasts from 30 patients. We observed frequent expression of TRAIL DcR1 and DcR2, while expression of DR4 and DR5 was less frequent. Nevertheless, the expression of DR4 or DR5 in leukaemic cells was always matched by a similar expression of one of the decoy receptors. Leukaemic blasts were invariably resistant, even to a high concentration (1000 ng/ml) of TRAIL. We suggest that AML blasts are resistant to TRAIL apoptosis in vitro. Therefore, it is unlikely that TRAIL alone might be used in the future as an innovative pharmacological agent for the treatment of AML.     

Characterization of tumour necrosis factor-alpha-related apoptosis-inducing ligand and its receptors in the adult human testis

Tumour necrosis factor-alpha-related apoptosis-inducing ligand (TRAIL) is a member of the tumour necrosis factor-alpha (TNF-alpha) family of cytokines which is known to induce apoptosis upon binding to its death domain-containing receptors, DR4/TRAIL-R1 and DR5/TRAIL-R2. Two additional TRAIL receptors, DcR1/TRAIL-R3 and DcR2/TRAIL-R4, lack functional death domains and act as decoy receptors for TRAIL. In this study, the presence of TRAIL and its receptors was investigated by immunohistochemistry in adult human testes. In addition, TRAIL and its receptors were studied in terms of protein and mRNA using western blot analysis and RT-PCR respectively. TRAIL and its receptors were immunodetected according to the different testicular cell types: TRAIL, DR5/TRAIL-R2 and DcR2/TRAIL-R4 were localized in Leydig cells, DR4/TRAIL-R1 was seen in peritubular and Sertoli cells whereas ligand and all receptors were detected in germ cells. Proteins and mRNA corresponding to TRAIL and its receptors were also identified in adult human testes. In conclusion, TRAIL and its receptors DR4/TRAIL-R1, DR5/TRAIL-R2, DcR1/TRAIL-R3 and DcR2/TRAIL-R4 are expressed in the human testis, and are predominantly localized in different germ cell types.     

Additive effect of TRAIL and p53 gene transfer on apoptosis of human lung cancer cell lines

TRAIL is a cytokine that can induce tumor-specific apoptosis through its specific death receptors (DR4 and DR5) and p53 has been proven to increase the expression of death receptors. To examine their interaction in tumor suppression, p53 and TRAIL genes were inserted in recombinant adenovirus vectors and transferred simultaneously into non-small cell lung cancer cell lines (NCI-H157, NCI-H358, NCI-H460 and A549). Western blot assay demonstrated production of TRAIL protein in NCI-H157 and A549 cell lines. Increased expressions of DR4 and DR5 of NCI-H157 and DR4 of A549 after p53 overexpression were confirmed by flow cytometry. p53 or TRAIL gene transfer increased sub-G1 fraction in cell cycle analysis and inhibited the tumor growth dose-dependently and the degree was potentiated by co-transfer. But isobologram analysis indicated an additive effect. Together, these data indicate that p53 and TRAIL interact additively on tumor apoptosis despite theoretical synergism.     

Osteoprotegerin (OPG) acts as an endogenous decoy receptor in tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis of fibroblast-like synovial cells

We examined the role of osteoprotegerin (OPG) on tumour necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in rheumatoid fibroblast-like synovial cells (FLS). OPG protein concentrations in synovial fluid from patients with rheumatoid arthritis (RA) correlated with those of interleukin (IL)-1beta or IL-6. A similar correlation was present between IL-1beta and IL-6 concentrations. Rheumatoid FLS in vitro expressed both death domain-containing receptors [death receptor 4 (DR4) and DR5] and decoy receptors [decoy receptor 1 (DcR1) and DcR2]. DR4 expression on FLS was weak compared with the expression of DR5, DcR1 and DcR2. Recombinant TRAIL (rTRAIL) rapidly induced apoptosis of FLS. DR5 as well as DR4 were functional with regard to TRAIL-mediated apoptosis induction in FLS; however, DR5 appeared be more efficient than DR4. In addition to soluble DR5 (sDR5) and sDR4, OPG administration significantly inhibited TRAIL-induced apoptogenic activity. OPG was identified in the culture supernatants of FLS, and its concentration increased significantly by the addition of IL-1beta in a time-dependent manner. Neither IL-6 nor tumour necrosis factor (TNF)-alpha increased the production of OPG from FLS. TRAIL-induced apoptogenic activity towards FLS was reduced when rTRAIL was added without exchanging the culture media, and this was particularly noticeable in the IL-1beta-stimulated FLS culture; however, the sensitivity of FLS to TRAIL-induced apoptosis itself was not changed by IL-1beta. Interestingly, neutralization of endogenous OPG by adding anti-OPG monoclonal antibody (MoAb) to FLS culture restored TRAIL-mediated apoptosis. Our data demonstrate that OPG is an endogenous decoy receptor for TRAIL-induced apoptosis of FLS. In addition, IL-1beta seems to promote the growth of rheumatoid synovial tissues through stimulation of OPG production, which interferes with TRAIL death signals in a competitive manner.