阿霉素联合TRAIL对人肝癌细胞增殖与TRAIL受体表达的影响

目的 探讨阿霉素联合肿瘤坏死因子相关凋亡诱导配体（TRAIL）对肝癌细胞HepG2和SMMC-7721增殖及TRAIL受体表达的影响。方法 采用MTT法分别检测阿霉素、TRAIL及低浓度阿霉素联合TRAIL处理HepG2和SMMC-7721细胞的生长抑制率;RT-PCR和Western blotting分别检测阿霉素作用前后HepG2和SMMC-7721细胞TRAIL受体DR4、DR5的mRNA和蛋白表达水平。结果 3种浓度阿霉素（0.86、8.6、86μmol／L）作用24h后,对HepG2和SMMC-7721细胞的生长抑制率分别为（8.84±0.44）％和（8.67±1.22）％、（24.12±1.11）％和（25.39±2.26）％、（64.55±4.05）％和（66.2±3.74）％,呈浓度依赖性,不同浓度组之间差异均有统计学意义（P＜0.05）。4种浓度TRAIL（10、100、500、1000ng／ml）作用24h后,对HepG2和SMMC 7721细胞的生长抑制率分别为（5.83±0.25）％和（5.66±0.56）％、（9.60±1.38）％和（8.96±1.13）％、（11.87±1.43）％和（12.11±1.84）％、（15.12±3.84）％和（16.16±1.41）％,其他3种浓度分别与10ng／ml TRAIL比较,差异均有统计学意义（P＜0.01）。低浓度阿霉素联合TRAIL作用于HepG2和SMMC-7721细胞,低浓度阿霉素能够增加HepG2和SMMC-7721细胞对TRAIL治疗的敏感性,并且随着时间的延长和TRAIL浓度的增加,细胞抑制率逐渐增加,呈时间 效应和剂量 效应关系;无论在mRNA还是蛋白水平,阿霉素处理后HepG2细胞死亡受体DR4、DR5的表达水平较未处理组显著增加;在SMMC-7721细胞,阿霉素处理后,DR5的表达水平显著增加,而DR4的表达水平与阿霉素未处理组相似。结论 低浓度阿霉素能够增加肝癌细胞对TRAIL治疗的敏感性,其机制可能是阿霉素增加死亡受体特别是DR5的表达水平,从而诱导细胞凋亡增加,TRAIL在肝癌治疗方面存在潜在的临床应用价值。     

肿瘤坏死因子相关凋亡诱导配体对白血病NB4和K562细胞的作用及与其受体表达的关系

 【摘要】　目的　探讨肿瘤坏死因子相关凋亡诱导配体 （TRAIL）对白血病NB4和K562细胞的作用及与其受体表达的关系。方法　以Jurkat细胞株为阳性对照,采用不同浓度的TRAIL分别作用于NB4和K562细胞,观察细胞形态;采用四甲基偶氮唑蓝（MTT）比色法检测细胞生长情况;用流式细胞术检测细胞表面TRAIL受体的表达情况。结果　TRAIL作用导致NB4细胞株生存率显著下降,但弱于Jurkat细胞株,其变化具有TRAIL作用时间和浓度依赖性;对K562细胞株生存率的影响不明显。NB4细胞表面死亡受体4（DR4）和DR5表达水平较高,同时诱骗受体1（DcR1）表达较高;K562细胞DR5表达水平较高,而DR4及DcR1微量表达;Jurkat细胞表面仅DR5低水平表达;DcR2在三株细胞表面均无表达。结论　NB4细胞对TRAIL中度敏感,K562细胞对TRAIL耐受;NB4细胞敏感性较低可能与DcR1表达有关,K562细胞耐受性与其表面TRAIL受体表达无关。     

可溶性肿瘤坏死因子相关凋亡诱导配体诱导肝癌细胞凋亡的研究

方法 采用原位杂交方法检测肝癌组织、肝癌细胞株以及正常肝组织中TRAILR的表达。采用不同浓度TRAIL蛋白处理肝癌细胞株Hep2和SMMC7721,应用流式细胞仪和原位末端标记,观察经药物处理前后该细胞株的凋亡发生率。结果 60例肝癌组织及20例正常肝组织均表达死亡受体DR5和DR4,但肝癌组织DR表达量显著强于正常肝组织。54例(90．0％)肝癌组织不表达诱捕受体DcR1,25例(41．7％)肝癌组织不表达DcR2,而20例正常肝组织均表达DcR。肝癌组织中DR的高表达及DcR的低表达,不同于正常肝组织中DR的低表达及DcR的高表达,两者间差异有显著性。两种肝癌细胞株中均可检测到DR5、DR4、DcR2的表达,但DcR1表达缺失。肝癌组织中DR的表达与肿瘤的分化、肿瘤分期有关,低分化的肿瘤DR表达减少(P＜0．01),Ⅲ、Ⅳ期肿瘤DR表达显著低于I、Ⅱ期(P＜0．05)。DR表达与患者的性别、年龄、HBsAg阳性与否、AFP水平、肿瘤大小以及是否转移无关。经TRAIL(100ng/ml)处理24h,肝癌细胞凋亡发生率约10％,而Jurkat细胞凋亡率达70％以上,胆管癌细胞QBC939凋亡发生率约50％。结论 肝细胞肝癌普遍存在TRAILR的表达,并存在受体类型的表达差异。但单一的TRAIL治疗只能有限的诱导肝癌细胞HepG2、SMMC7721发生凋亡,HCC对TRAIL诱导的凋亡存在耐药现象。     

NS-398联合表阿霉素对肝癌HepG2细胞增殖及survivin表达的影响

[目的]探讨表阿霉素联合COX-2抑制剂NS-398对HepG2细胞增殖及survivin表达的影响.[方法]不同浓度表阿霉素单药或联合不同浓度NS-398分别作用于肝癌HepG2细胞株,MTT法测定表阿霉素联合NS-398对细胞生长的抑制率,RT-PCR和免疫荧光法分别检测HepG2细胞中survivin mRNA与survivin蛋白表达量的变化.[结果]单药表阿霉素对HepG2细胞有显著的抑制作用,且与NS-398联合应用后抑制作用更明显.正常无药对照组HepG2细胞中survivin蛋白和mRNA均呈强表达,表达水平分别为68.970±1.156和0.919±0.021;且在胞浆中survivin蛋白表达强于胞核.表阿霉素组HepG2细胞中survivin蛋白(47.630±0.863)和mRNA (0.749±0.014)水平均明显降低,联合组survivin蛋白(27.544±0.748)和mRNA(0.481±0.012)水平降低更显著(F=1065.233,P＜0.05;F=304.553,P＜0.05).[结论]NS-398联合表阿霉素可明显抑制HepG2细胞生长,NS-398可显著增强表阿霉素的抗癌作用;两者联合可明显下调HepG2细胞株中survivin蛋白和mRNA的表达.     

TRAIL与卡铂联合诱导卵巢癌细胞凋亡的研究

目的探讨肿瘤坏死因子相关凋亡诱导配体（TRAIL）与卡铂（CBP）联合应用对体外培养的卵巢A2780细胞的生物学效应及其作用机制。方法采用MTT法、流式细胞术，检测体外培养的A2780细胞在卡铂和TRAIL共同作用下的细胞增殖抑制效应以及细胞凋亡程度，应用半定量逆转录多聚酶链反应（RT-PCR）法检测TRAIL受体的mRNA表达水平。结果A2780细胞对TRAIL敏感，TRAIL与卡铂联合用药对细胞的增殖抑制呈现高效协同作用，与单独用药组比较有显著性差异（P〈0．05）；流式细胞术分析协同性杀伤作用主要由于TRAIL和CBP联合诱导细胞凋亡引起；RT—PCR法检测结果显示A2780细胞在TRAIL与卡铂联合用药后均表现死亡受体DR4、DR5表达水平上调和诱骗受体DcR1、DcR2表达水平下调。结论在体外TRAIL与化疗药物联用能明显抑制肿瘤细胞增殖，诱导肿瘤细胞凋亡，卡铂能明显增强TRAIL对肿瘤细胞的敏感性，其诱导机制可能与死亡受体DR4、DR5表达水平上调和诱骗受体DcR1、DcR2表达水平下调相关。     

TRAIL与阿霉素联用协同杀伤人结肠癌细胞SW480

背景与目的:肿瘤坏死因子相关凋亡诱导配体(tumornecrosisfactor-relatedapoptosisinducingligand,TRAIL)可选择性杀伤肿瘤细胞,而不影响正常细胞生长。当一部分肿瘤细胞对TRAIL不敏感时,特定的其它药物可增强其杀伤作用。本文旨在探讨结肠癌细胞SW480对TRAIL的敏感性,以及TRAIL与阿霉素联用对细胞的杀伤作用及可能作用机制。方法:常规培养结肠癌细胞SW480。利用MTT法检测细胞毒性作用,流式细胞术定量分析凋亡细胞比例,透射电镜在亚细胞结构形态上证实凋亡细胞,Westernblot分析p53及bcl-2蛋白表达变化。结果:(1)SW480细胞对TRAIL不敏感,100ng/mlTRAIL只能杀伤7.8%的细胞,IC50>1000ng/ml,且不存在浓度依赖性。(2)SW480细胞对阿霉素敏感,存在浓度依赖性作用,IC50=65μmol/L,0.86μmol/L的阿霉素对细胞不表现杀伤作用。(3)TRAIL与阿霉素合用表现出协同作用,亚毒性浓度TRAIL(100ng/ml)与亚毒性浓度阿霉素(0.86μmol/L)联用可杀伤80%SW480细胞。流式细胞学证实这种杀伤作用主要通过诱导细胞凋亡实现,透射电镜亦观察到大量凋亡细胞存在。药物作用前后,p53及bcl-2蛋白表达水平无明显改变。结论:结肠癌细胞株SW480对TRAIL不敏感,但TRAIL与亚毒性浓度阿霉素联用对癌细胞有协同杀伤作用,这种细胞毒性作用主要表现     

热疗联合阿霉素和TRAIL对肝癌HepG2细胞凋亡的影响

目的:观察热疗（hyperthermia,HT）联合亚浓度阿霉素(adriamycin,ADM)和肿瘤坏死因子相关凋亡诱导配体（tumor necrosis factor related apoptosis inducing ligand,TRAIL）对肝癌HepG2细胞凋亡的影响,以确定联合方案是否具有协同作用。方法:采用CCK8法检测细胞的活性;Hoechst 33258染色实验检测细胞的形态变化;流式细胞仪检测细胞的凋亡;Western blot实验检测细胞内蛋白的表达水平。结果:HT联合ADM和TRAIL可明显抑制肝癌HepG2细胞的活性（P＜0.05）,促进细胞染色质浓缩、核碎裂。流式细胞检测结果表明,HT联合ADM和TRAIL可促进细胞的早期凋亡（P＜0.001）和晚期凋亡（P＜0.01）。Western blot实验进一步证明,HT联合ADM和TRAIL通过上调DR4、DR5、caspase-3和caspase-8蛋白的表达来促进细胞的凋亡（P＜0.05）。结论:HT联合ADM和TRAIL具有协同作用,可明显增加细胞凋亡的敏感性,促进肝癌细胞的凋亡。     

死亡受体5与肝癌细胞凋亡的相关性

目的探讨人死亡受体5(DR5)及其配体(TRAIL)和竞争性单克隆抗体(DR5mAb)对肝癌细胞凋亡的影响。方法采用半定量RT-PCR及Western blot法检测肝癌细胞株HepG2、SMMC7721和正常人肝细胞株LO2的DR5在mRNA和蛋白水平的表达含量。应用四甲基偶氮唑盐法测试细胞的生长曲线,以观察TRAIL和DR5mAb对肝癌细胞生长的抑制作用,并用流式细胞仪测定细胞的凋亡率。结果肝癌细胞株HepG2、SMMC7721的DR5高表达,正常人肝细胞株LO2的DR5低表达,差异有统计学意义(P<0.05)。肝癌细胞的增殖率随着TRAIL浓度的增加而逐渐降低,但当TRAIL超过1000ng/ml时,肝癌细胞株的增殖率就不再下降;而肝癌细胞的增殖率随着DR5mAb浓度的增加而逐渐降低,呈现明显的剂量依赖关系。1000ng/ml TRAIL处理24h时,HepG2的凋亡率在14.74%±0.48%,继续增加TRAIL浓度,其凋亡率无显著改变;而同样剂量的DR5mAb处理24h时,HepG2的凋亡率高达52.45%±0.57%,明显高于前者(P<0.05)。同时发现,正常人肝细胞株LO2的增殖率随着TRAIL浓度的增加呈下降趋势,与PBS阴性对照组差异有统计学意义(P<0.05);而DR5mAb的浓度变化对人正常肝细胞株LO2无明显影响。结论死亡受体DR5在诱导肝癌细胞凋亡中起重要的作用;DR5mAb选择性地诱导肝癌细胞凋亡,对人正常肝细胞无诱导凋亡作用。     

TRAIL受体在人肝细胞癌中的表达及TRAIL诱导的肝癌细胞凋亡

目的 研究了RAIL受体在肝癌组织及肝癌细胞中的表达,探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)及其受体在肝癌细胞凋亡诱导中的作用。 方法 应用RT-PCR法和免疫组化方法检测肝癌组织及细胞系SK-Hepl中TRAIL受体的表达,并以TRAIL蛋白和γ-干扰素作用于SK-Hepl细胞,观察其对细胞的凋亡诱导作用。 结果 在肝癌组织及肝癌SK-Hepl细胞系中均可检测到TRAIL受体,其中,死亡受体DR4、DR5在肝癌、癌旁组织以及SK-Hepl肝癌细胞系中均呈高表达,而诱骗受体DcR1及DcR2呈低表达,明显低于正常组织。TRAIL对肝癌细胞有凋亡诱导作用,与干扰素的协同时,其作用明显增强。 结论 肝癌组织中存在着TRAIL受体的表达,TRAIL可诱导肝癌SK-Hepl细胞系凋亡,其作用与DR4、DR5的高表达有关。     

卡铂联合TRAIL对肺癌A549细胞增殖和凋亡的影响

目的:观察卡铂联合TNF相关凋亡诱导配体(TRAIL)对人肺腺癌细胞A549增殖和凋亡的影响。方法:经20、40、80 μg/mL卡铂和100 ng/μL TRAIL单用或联用处理后,用MTS法检测A549细胞的增殖能力,在光镜下观察细胞形态学变化;并采用流式细胞术检测细胞凋亡情况;RT-PCR和Western blot法检测死亡受体4(DR4)、死亡受体5(DR5)、Survivin和X连锁凋亡抑制蛋白基因(XIAP)mRNA与蛋白表达的变化。结果:卡铂和TRAIL单用或联用均可浓度依赖性抑制A549细胞的增殖,诱导其凋亡,两药联用比单用卡铂时抑制率和凋亡率更高(P<0.05)。单用卡铂或TRAIL可使A549细胞数减少,漂浮细胞增多,出现明显的凋亡形态变化,且明显降低Survivin和XIAP的mRNA和蛋白表达水平(P均<0.05);但对A549细胞DR4和DR5 mRNA表达均无明显影响,而单用卡铂或TRAIL却能升高A549细胞DR5蛋白的表达(P<0.05)。与单用组相比,TRAIL与卡铂联用A549细胞凋亡形态变化更明显,可明显降低A549细胞Survivin和XIAP mRNA和蛋白的表达水平及升高DR5蛋白表达水平(P<0.05)。结论:卡铂与TRAIL联用可协同抑制肺癌细胞A549细胞增殖,促进其凋亡,且与卡铂能够增加A549细胞DR5蛋白的表达和降低Survivin及XIAP的表达相关。     

TRAIL及其受体在乳腺癌组织中的表达及意义

目的探讨肿瘤坏死因子相关凋亡诱导配体（TRAIL）及其受体（DR4、DR5、DcR1、DcR2）在乳腺癌组织的表达及意义。方法用反转录聚合酶链反应（RT-PCR）法检测60例乳腺癌及对应的正常乳腺组织中TRAIL及其受体的表达。结果乳腺癌组织中TRAIL、DcR1、DcR2表达均低于正常乳腺组织(P＜0.05),且TRAIL及其受体的表达与乳腺癌的分期、分级等无关(P＞0.05)。结论TRAIL及其受体在乳腺癌凋亡过程中起着重要的作用,TRAIL及其诱骗受体低表达同乳腺癌的发生关系密切。     

Ewing's sarcoma family tumors are sensitive to tumor necrosis factor-related apoptosis-inducing ligand and express death receptor 4 and death receptor 5

In this study, we investigated the sensitivity of Ewing's sarcoma family tumors (ESFTs) of children and adolescents to the tumor necrosis factor-related apoptosis-inducing Ligand (TRAIL). TRAIL binds to death receptors (DRs) DR4, DR5, DcR1, and DcR2. Either DR4 or DR5 can induce apoptosis, whereas DcR1 and DcR2 are considered inhibitory receptors. Nine of 10 ESFT cell lines, including several that were Fas resistant, underwent apoptosis with TRAIL through activation of caspase-10, capase-8 (FLICE), caspase-3, and caspase-9. In contrast to the Fas signaling pathway, caspase-10, but not caspase-8 or the Fas-associated death domain-containing molecule, was recruited to the TRAIL receptor-associated signaling complex. We found that 9 of 10 ESFT cell lines expressed both DR4 and DR5 by Western blotting, whereas the TRAIL-resistant line expressed only DR4. However, DR4 was absent from the cell surface in the resistant and two additional lines (three of five tested lines), suggesting that it may have been nonfunctional. On the contrary, DR5 was located on the cell surface in all four sensitive lines tested, being absent only from the cell surface of the resistant line that was also DR5-negative by Western blotting. In agreement with these findings, the resistance of the line was overcome by restoration of DR5 levels by transfection. Levels of DcR1 and DcR2 or levels of the FLICE-inhibitory protein (FLIP) did not correlate with TRAIL resistance, and protein synthesis inhibition did not sensitize the TRAIL-resistant line to TRAIL. Because these data suggested that sensitivity of ESFTs to TRAIL was mainly based on the presence of DR4/DR5, we investigated the presence of these receptors in 32 ESFT tissue sections by immunohistochemistry. We found that 23 of 32 tumor tissues (72%) expressed both receptors, 8 of 32 (25%) expressed one receptor only, and 1 was negative for both. Our finding of wide expression of DR4/DR5 in ESFT in vivo, in combination with their high sensitivity to TRAIL in vitro and the reported lack of toxicity of TRAIL in mice and monkeys, suggests that TRAIL may be a novel effective agent in the treatment of ESFTs.     

Preparation and characterization of a set of monoclonal antibodies to TRAIL and TRAIL receptors DR4, DR5, DcR1, and DcR2

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo 2L) is a novel cytotoxic ligand belonging to TNF superfamily. Among TRAIL receptors, death receptor 4 (DR4) and DR5 containing death domain (DD) in their cytoplasmic region mediate apoptosis-signaling upon TRAIL binding, while decoy receptor 1 (DcR1) and DcR2 with a truncated or non-functional DD play "decoy" role. The interaction of TRAIL and TRAIL receptors plays important roles both in immunoregulation and immune pathogenesis of some diseases. In this study, we raised hybridomas secreting monoclonal antibodies against TRAIL (FMU1.1, 1.2, 1.3), DR4 (FMU1.4), DR5 (FMU1.5, 1.6), DcR1 (FMU1.7) and DcR2 (FMU1.8, 1.9). These MAbs could be used for fluorescent staining and flow cytometry (FCM) analysis as well as immunohistochemistry (IHC). Moreover, FMU1.1, 1.3, 1.4 and 1.5 could be used as coating antibodies paring corresponding polyclonal antibodies to develop sandwich ELISAs to quantitate the soluble TRAIL (sTRAIL), sDR4 or sDR5 in serum samples respectively. In addition, cross-linking of DR4/DR5 by FMU1.4 or FMU1.5 MAbs could induce apoptosis of some DR4/DR5-expressing tumor cells. Thus, this set of monoclonal antibodies against TRAIL or TRAIL receptors may be useful in expression phenotypic and functional study of TRAIL and TRAIL receptors.     

TRAIL与顺铂联合应用对喉鳞癌细胞Hep-2的体外作用

目的：探讨肿瘤坏死因子相关诱导凋亡配体（tumor necrosis factor-related apoptosis-inducing ligand，TRAIL）与顺铂联合应用对喉鳞癌细胞Hep-2的抑制作用。方法：CCK-8测定TRAIL和顺铂对Hep-2细胞生长的抑制率；流式细胞术检测细胞表面TRAIL受体的表达及细胞凋亡。结果：Hep-2细胞对TRAIL诱导的凋亡不敏感，顺铂通过上调细胞表面死亡受体的表达而增强Hep-2细胞对TRAIL的敏感性。结论：顺铂可使Hep-2细胞克服对TRAIL的耐受性，两者具有协同作用，有望应用于喉癌的临床治疗。     

TRAIL及其受体DR4、DcR1在大肠癌及癌旁组织中的表达

 目的研究人肿瘤坏死因子相关凋亡诱导配体(TNF-related apoptosis inducing ligand,TRAIL)及其受体DR4、DcR1在大肠癌和癌旁组织中的表达及意义。方法采用免疫组化SP法检测42例大肠癌及其癌旁5cm组织、25例正常大肠粘膜组织中TRAIL及其受体DR4、DcR1表达水平。结果TRAIL及DR4在大肠癌、癌旁组织及正常大肠粘膜组织中的表达呈递增趋势,而DcR1的表达则与之相反(P<0.05);TRAIL和DR4在中、低分化癌中的表达明显低于高分化癌中的表达,而DcR1的表达则与之相反(P<0.01);TRAIL、DR4、DcR1的表达与肿瘤的病理类型、Duke′s分期及淋巴结转移与否等因素无关(P>0.05)。结论TRAIL、DR4、DcR1可能与大肠癌的发生、发展密切相关;DR4可能在TRAIL诱导的凋亡通路中发挥一定作用,而DcR1的表达与否一定程度上决定了TRAIL能否发挥其生物效应。     

Tumor-specific down-regulation of the tumor necrosis factor-related apoptosis-inducing ligand decoy receptors DcR1 and DcR2 is associated with dense promoter hypermethylation

TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) induces apoptosis in a large variety of cancer cells but not in most normal human cells. This feature makes TRAIL, a potential antitumor agent. TRAIL can bind to four different receptors, two pro-apoptotic death receptors (DRs), DR4 and DR5, and two antiapoptotic decoy receptors (DcRs), DcR1 and DcR2. Normal cells express all four of the receptors. The increased TRAIL sensitivity of tumor cells has been postulated to result from the lack of DcR expression. We studied the tumor-specific down-regulation of the TRAIL receptors DcR1 and DcR2, as well as DR4 and DR5, in a group of pediatric tumor cell lines [nine neuroblastoma and three peripheral primitive neuro-ectodermal tumors (PNETs)] and three cell lines from adult tumors. Lack of expression of DcR1 and DcR2 was widespread (13 of the 15 cell lines and 10 of 15, respectively), both in the adult tumor cell lines and in the pediatric tumor lines. DR4 and DR5 were expressed in 8 of 15 and 12 of 15 cell lines, respectively. To understand the tumor-specific down-regulation of the TRAIL receptors, the promoter regions were studied for possible methylation changes of their CpG islands. All normal tissues were completely unmethylated, whereas in the tumor cell lines, we found frequent hypermethylation of the promoter. For DcR1 and DcR2, we found dense hypermethylation in 9 (69%) of 13 and 9 (90%) of 10 of nonexpressing cell lines, respectively. DR4 and DR5 were methylated in 5 (71%) of 7 and 2 (67%) of 3 nonexpressing cell lines, respectively. Treatment with the demethylating agent 5-aza-2'deoxycytidine resulted in partial demethylation and restored mRNA expression. In addition, we performed mutation analysis of the death domains of DR4 and DR5 by sequencing exon 9. Mutations were not present in any of the neuroblastoma or PNET cell lines. A panel of 28 fresh neuroblastoma tumor samples also lacked expression of DcR1 and DcR2 in 85 and 74% of cases, respectively. Hypermethylation was observed in 6 (21%) of 28 for DcR1 and 7 (25%) of 28 for DcR2. DR4 and DR5 were both expressed in 22 of 28 tumors, and no promoter methylation was observed. These data suggest that hypermethylation of the promoters of DcR1 and DcR2 is important in the down-regulation of expression in neuroblastoma and other tumor types.     

TRAIL death receptor-4 expression positively correlates with the tumor grade in breast cancer patients with invasive ductal carcinoma

PURPOSE: Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) selectively induces apoptosis in cancer cells but not in normal cells, and a number of clinical trials have recently been initiated to test the safety and antitumoral potential of TRAIL in cancer patients. Four different receptors have been identified to interact with TRAIL: two are death-inducing receptors (TRAIL-R1 [DR4] and TRAIL-R2 [DR5]), whereas the other two (TRAIL-R3 [DcR1] and TRAIL-R4 [DcR2]) do not induce death upon ligation and are believed to counteract TRAIL-induced cytotoxicity. Because high levels of DcR2 expression have recently been correlated with carcinogenesis in the prostate and lung, this study investigated the importance of TRAIL and TRAIL receptor expression in breast cancer patients with invasive ductal carcinoma, taking various prognostic markers into consideration. METHODS AND MATERIALS: Immunohistochemical analyses were performed on 90 breast cancer patients with invasive ductal carcinoma using TRAIL and TRAIL receptor-specific antibodies. Age, menopausal status, tumor size, lymph node status, tumor grade, lymphovascular invasion, perineural invasion, extracapsular tumor extension, presence of an extensive intraductal component, multicentricity, estrogen and progesterone receptor status, and CerbB2 expression levels were analyzed with respect to TRAIL/TRAIL receptor expression patterns. RESULTS: The highest TRAIL receptor expressed in patients with invasive ductal carcinoma was DR4. Although progesterone receptor-positive patients exhibited lower DR5 expression, CerbB2-positive tissues displayed higher levels of both DR5 and TRAIL expressions. CONCLUSIONS: DR4 expression positively correlates with the tumor grade in breast cancer patients with invasive ductal carcinoma.     

Polymorphisms in TRAIL receptor genes and risk of breast cancer in Spanish women

TRAIL is a potent inducer of apoptosis in malignant but not in normal cells. TRAIL binds to the proapoptotic death receptor DR4 and DR5 as well as to the decoy receptors DcR1 and DcR2. To evaluate the involvement of TRAIL receptor genes in breast cancer, we carried out a case-control study of eight selected polymorphisms in a large sample of Spanish women. Three of the eight selected SNPs (626G/C and 1322G/A in DR4 and 2699A/G in DcR2) showed some evidence of different genotype distributions in a random selection of 535 cases and 480 controls and were therefore studied in our entire sample (1008 cases and 768 controls). For the two DR4 polymorphisms, no differences in genotype or haplotype distribution were found between cases and controls. Interestingly, allele 2699G in the decoy receptor DcR2 appears associated with reduced breast cancer risk (P=0.05). Given that it is located in the 3' UTR, its effect might be related to DcR2 mRNA instability, or linkage disequilibrium with a functional variant residing in either DcR2 or neighbouring genes. A decreased efficiency of DcR2 to work as decoy receptor for TRAIL, would facilitate the apoptotic pathway in cells at risk.     

Synergistic antitumor activity of TRAIL combined with chemotherapeutic agents in A549 cell lines in vitro and in vivo

Purpose To investigate the synergistic cytotoxicity of TRAIL in combination with chemotherapeutic agents in A549 cell lines, we systematically evaluated the cytotoxicity of TRAIL alone and TRAIL in combination with cisplatin, paclitaxel (Taxol) or actinomycin D in A549 cell lines in vitro and in vivo, and whether the sensitivity was correlated with the expression level of TRAIL receptors.Methods We investigated the cytotoxicity of TRAIL alone and the synergistic antitumor effects of TRAIL in combination with chemotherapeutic agents in A549 cells by crystal violet staining and FACS in vitro. The expression levels of DR4, DR5, DcR1 and DcR2 were measured in TRAIL-treated and chemotherapeutic agent-treated A549 cells by Western blotting. The growth inhibition of tumors was evaluated in terms of incidence, volume and weight in a A549-implanted nude mice model.Results Chemotherapeutic agents cisplatin (5.56 g/ml), Taxol (10 and 30 g/ml) or actinomycin D (9.26, 83.3 and 750 ng/ml) augmented the cytotoxicity of TRAIL in A549 cell lines within a range of concentrations of TRAIL (1.98–160 ng/ml) in vitro. The expression levels of DR4 and DR5 were not significantly different and the expression of DcR2 was slightly downregulated, but the expression of DcR1 was not detected in non-treated, TRAIL-treated and chemotherapeutic agent-treated A549 cells. The rates of tumor inhibition following treatment with TRAIL alone (15 mg/kg per day, daily for 10 days) and TRAIL/cisplatin (15 mg/kg per day TRAIL, daily for 10 days; 1.5 mg/kg per day cisplatin, daily for 10 days with 7-day intervals) were 28.3% and 76.8% by tumor weight (P<0.05 for TRAIL alone versus control, P<0.05 for TRAIL/cisplatin versus cisplatin alone and TRAIL alone) on day 65 in vivo.Conclusion TRAIL in combination with chemotherapeutic agents cisplatin, Taxol or actinomycin D exerted synergistic antitumor effects in A549 cell lines in vitro and TRAIL/cisplatin demonstrated synergistic antitumor effects in vivo. The expression levels of TRAIL receptors suggested that the synergistic effects of TRAIL in combination with chemotherapeutic agents are not at the receptor level in A549 cell lines.Abbreviations TNF Tumor necrosis factor - TRAIL TNF-related apoptosis-inducing ligand - NSCLC Non-small cell lung cancer - DR Death receptor - DcR Decoy receptor - IB Inclusion body - FACS Fluorescence activated cell sorter - PI Propidium iodide - IR Rate of inhibition - PMSF Phenyl methyl sulfonyl fluoride