TRAIL联合环氧合酶抑制剂体外诱导肝癌细胞凋亡的实验研究

目的 探讨塞莱昔布增加TRAIL诱导肝癌细胞HepG2、Hep3B凋亡的分子机制.方法 应用流式细胞仪分析塞莱昔布联合应用TRAIL对肝癌细胞HepG2和Hep3B细胞周期的影响;Western blot检测HepG2和Hep3B细胞在塞莱昔布作用前后凋亡信号传导蛋白caspase-8,caspase-3,caspase-9,DR4,DR5,DcR1,c-FLIP,RIP,Cytc,Smac和Bid的表达变化.结果 联合用药组中HepG2及Hep3B细胞生存率分别为29.37%±2.68%和22.75%±2.77%,显著低于塞莱昔布单独用药组的73.04%±4.03%和66.90%±3.47%(t=9.975,P＜0.01).塞莱昔布预先处理能够下调c-FLIP及RIP的表达及增加Cytc、Smac、Bid的表达,但对DR4、DR5、DcR1的表达无明显影响.结论 TRAIL联合塞莱昔布通过下调c-FLIP及RIP的表达,活化死亡受体通路及上调Bid的表达,激活线粒体通路诱导肝癌细胞凋亡.     

TRAIL联合顺铂诱导肝癌细胞HepG2凋亡的研究

目的 探讨顺铂增加TRAIL诱导肝癌细胞HepG2凋亡的分子机制，提供TRAIL应用肝癌临床治疗的一种新的用药模式。方法 以肝癌细胞HepG2为研究对象，应用流式细胞仪分析顺铂联合应用TRAIL对细胞周期的影响，Western blot检测顺铂作用前后HepG2细胞在TRAIL诱导凋亡过程中Caspase-8、Caspase-3、DR4、DR、DcR，c—FLIP及RIP的表达变化。结果 顺铂能够增强TRAIL诱导HepG2细胞凋亡的能力，两者联合应用具有明显的协同作用，顺铂预先处理能够下调c-FLIP及RIP的表达及增加DR的表达。结论 TRAIL联合顺铂可以诱导肝癌细胞HepG2凋亡，其机制是通过下调c-FLIP及RIP的表达，解除Caspase-8受抑，恢复凋亡信号的传导来实现的。死亡受体D＆的表达上调也可能参与了这一变化过程。     

受体作用蛋白在肝癌细胞对肿瘤坏死因子相关凋亡诱导配体诱导凋亡耐受中的作用

目的 观察受体作用蛋白(RIP)基因的表达变化在肝癌细胞对肿瘤坏死因子相关凋亡诱导配体(TRAIL)诱导凋亡耐受中的作用.方法 以肝癌细胞HepG2、Hep3B为研究对象,制备RIP siRNA的细胞模型,应用流式细胞仪分析两种细胞模型对TRAIL作用后细胞周期的变化,Western blot检测其在RIP基因沉默前后凋亡信号传导蛋白Caspase-8、Caspase-3、DFF-45的表达变化.结果 转染RIP siRNA后,细胞恢复了对TRAIL诱导凋亡的敏感性,当TRAIL浓度为100 μg/L时,HepG2及Hep3B转染组的细胞生存率为(60.02±5.23)％和(50.78±3.76)％,显著低于对照组的(96.44±5.43)％和(101.85±6.41)％(P＜0.01);细胞生存周期SubG1期为(76.89±6.68)％和(72.45±7.31)％,显著高于对照组的(0.78±0.07)％和(3.62±0.38)％(P＜0.01).转染组TRAIL单独作用,可以引起HepG2 siRNA及Hep3B siRNA凋亡传导通路上传导蛋白Caspase-8、Caspase-3的裂解.结论 肝癌细胞对TRAI诱导凋亡的耐受可能与其传导通路上RIP蛋白的表达相关,抑制其表达可以导致凋亡传导蛋白Caspase-8、Caspase-3的裂解,促使凋亡的发生,恢复肝癌细胞对TRAIL诱导凋亡的敏感性.     

TRAIL联合HSP90抑制剂17-AAG诱导肝癌细胞凋亡的研究

目的 探讨17-AAG增加TRAIL诱导肝癌细胞HepG2凋亡的分子机制.方法 应用流式细胞仪分析17-AAG联用TRAIL对肝癌细胞HepG2细胞周期的影响;Western blot检测HepG2细胞在17-AAG作用前后凋亡信号传导蛋白Caspase-8、caspa8e-3、c-FLIP、RIP及NF-KB上游调节激酶Akt、IKb-α蛋白的表达变化.结果 联合用药组的细胞生存率为(17.25±2.34)%,显著低于17-AAG单独用药组的[(93.14±5.25)%,P<0.01];17-AAG预处理,随其浓度和时间的增加能明显下调RIP的表达,进而影响Akt的磷酸化,但对c-FLIP的表达无明显影响.结论 TRAIL联合17-AAG可以诱导肝癌细胞凋亡,其机制是通过下调RIP的表达,活化凋亡发生的死亡受体通路及阻断NF-κB通路来实现的.     

二甲双胍增强膀胱癌5637细胞对TRAIL的敏感性及其机制研究

目的探讨二甲双胍能否增强膀胱癌5637细胞对肿瘤坏死因子相关凋亡诱导配体(TRAIL)诱导细胞凋亡的敏感性及其机制。方法 MTT法检测不同浓度TRAIL(0、10、20、40、60、100 ng/mL)和二甲双胍(10 mM)联合用药对膀胱癌5637细胞的增殖抑制作用。Annexin V-FITC/PI双染检测二甲双胍对TRAIL诱导5637细胞凋亡的影响。Western blot检测二甲双胍和/或TRAIL干预5637细胞24小时后对caspase-8、caspase-3、PARP、DR4、DR5和c-FLIPL表达的影响。结果二甲双胍可增强TRAIL对膀胱癌5637细胞的增殖抑制作用和凋亡诱导作用,二甲双胍单独用药并未上调DR4和DR5表达,但显著下调c-FLIPL表达。结论二甲双胍显著增强膀胱癌5637细胞对TRAIL的敏感性,其机制可能与二甲双胍下调c-FLIPL表达有关。     

白细胞介素12通过抑制survivin表达加强肿瘤坏死因子相关凋亡诱导配体诱导的肝癌细胞凋亡

目的 探讨肿瘤坏死因子相关凋亡诱导配体(TRAIL)对肝细胞癌(HCC)的治疗作用,以及TRAIL耐药的可能机制和逆转耐药方案。方法 采用原位杂交方法观察HCC与正常肝组织中TRAIL的表达差异。采用不同浓度的sTRAIL(可溶性)处理HCC细胞株及真核表达质粒pIRES-EGFP-sTRAIL转染HCC细胞株,观察sTRAIL的抑癌疗效。建立裸鼠肝癌模型,观察sTRAIL的体内抑癌作用。进一步,检测HCC中survivin的表达并采用反义寡核苷酸封闭治疗。最后,观测sTRAIL和IL-12联合抗癌效果。结果 肝癌组织DR表达量显著强于正常肝组织DR表达量。60例肝癌组织中54例不表达诱捕受体DcRl,25例不表达DcR2,而20例正常肝组织均表达DcR。两种．HCC细胞株中DcR1表达缺失。经sTRAIL(100ng/ml)处理24h,HCC细胞凋亡发生率约10％,而Jurkat细胞凋亡率达70％以上。体外pIRES-EGFP-sTRAIL转染对肝癌细胞杀伤作用不敏感。体内直接瘤体注射pIRES-EGFP-sTRAIL可对裸鼠肝癌无明显抑制作用。HCC高表达survivin,反义寡核苷酸封闭可部分逆转TRAIL耐药。IL-12使survivin表达明显下调,显著加强TRAIL对HCC细胞的杀伤作用。结论 HCC对TRAIL诱导的凋亡有耐药现象。survivin参与HCC对TRAIL的耐药机制,反义寡核苷酸封闭可部分逆转TRAIL耐药。IL-12可通过抑制siurvivin表达增强TRAIL对HCC杀癌作用。联合基因治疗(如TRAIL和IL-12基因)可能成为一种有前途HCC治疗方案。     

TRAIL的抗肝细胞癌作用研究

目的 探讨TRAIL对HCC的治疗作用。方法 用不同浓度TRAIL处理肝癌细胞株HepG2、SMMC7721，观察经药物处理前后肿瘤细胞的凋亡发生率。采用分子克隆技术构建了真核表达质粒pIRES-EGFP-TRAIL，转染肝癌细胞株HepG2、SMMC7721细胞，观察其疗效。体内实验建立裸鼠肝癌模型，观察TRAn。的抑癌作用。结果TRAR，(100ng／m1)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％。真核表达质粒TRAIL体外转染肝癌细胞后对肝癌细胞的生长无显著性的抑制作用。体内直接瘤体注射pIRES-EGFP-TRAIL可有效的导入TRAIL基因并获得高表达，但对裸鼠肝癌无明显抑制作用。结论 肝细胞癌对TRAIL诱导的凋亡有耐药现象，提示HCC中存在抑制TRAIL诱导凋亡的因素，单一的TRAIL疗HCC疗效有限。     

TRAIL信号通路在胃癌的研究现状

目的介绍肿瘤坏死因子相关凋亡诱导配体（TRAIL）及其受体在胃癌的研究现状。方法检索PUB-MEDLINE和中国期刊全文数据库（CJFD），综述国内、外近年关于TRAII．及其受体在胃癌的相关研究文献。结果TRAIL在胃癌组织表达水平报道情况差异较大，但其与胃癌的分化程度和浸润、转移情况密切相关。其受体DR4及DR5在胃癌组织均表达阳性，而DcR1及DcR2在胃癌组织亦有表达阳性的报道。caspase-3、caspase-8和survivin对胃癌TRAIL信号通路有重要调节作用。5-氮2，-杂脱氧胞苷、阿霉素、5-氟尿嘧啶、α-生育酚及X射线照射可协同增强TRAIL对胃癌细胞的凋亡诱导作用。结论胃癌可能适合TRAIL靶向治疗，但其作用机理较为复杂并受到多因素影响。尚有如何有效增强和调控TRAIL凋亡诱导作用及TRAIL有何潜在毒性等诸多问题亟待研究。     

肿瘤相关凋亡诱导配体、Survivin、Caspase-3和NF-κB在大肠癌中的表达

肿瘤相关凋亡诱导配体（TRAIL）与FasL有较高的同源性，其选择性地诱导肿瘤细胞发生凋亡，从而使正常细胞逃逸其杀伤作用。有研究结果表明，许多肿瘤对TRAIL并不敏感．Sunivin、NF-κB和Caspase．3是TRAIL诱导细胞凋亡通路中三个关键性的影响因子。我们通过其在大肠癌中的表达的研究以期阐明TRAIL的效能与Survivin、Caspase．3和NF-κB表达的关系。     

大肠癌中肿瘤坏死因子相关凋亡诱导配体及其影响因子表达的研究

肿瘤坏死因子相关凋亡诱导配体（TRAIL）具有选择性诱导肿瘤细胞发生凋亡的作用。但随着研究深入，人们发现许多肿瘤对TRAIL并不敏感。我们通过研究TRAIL诱导细胞凋亡通路中3个关键性影响因子Survivin、NF-κB和Caspase-3在大肠癌中的表达来探寻提高TRAIL对肿瘤细胞敏感性的可能途径。     

Thapsigargin potentiates TRAIL-induced apoptosis in giant cell tumor of bone

TNF-related apoptosis-inducing ligand (TRAIL) is capable of causing apoptosis in tumor cells but not in normal cells; however, it has been shown that certain types of tumor cells are resistant to TRAIL-induced apoptosis. In this study, we examined the potentiation of TRAIL-induced apoptosis in the stromal-like tumor cells of giant cell tumor of bone (GCT). We show that both mRNA and protein of TRAIL receptors—death receptors (DR4, DR5) and decoy receptors (DcR1, DcR2) are present in GCT stromal tumor cells. However, the expression profiles in all GCT clones tested do not readily correlate with their differential sensitivity to TRAIL. To this end, we selected thapsigargin (TG), an agent known to cause perturbations in intracellular Ca²⁺ homeostasis to enhance the apoptotic action of TRAIL. When added alone, neither TRAIL nor TG induces a therapeutically important magnitude of cell death in GCT tumor cells. Interdependently, scheduled treatment of the cultures with TG followed by subsequent addition of TRAIL resulted in a significant synergistic apoptotic activity, while in contrast, no obvious augmentation was seen when TRAIL was added before TG. This effect was in accord with our observation that TG predominantly up-regulated both mRNA and protein expression of DR5, as well as DR4 mRNA while down-regulating DcR1 protein in GCT stromal-like tumor cells. Taken together, our findings suggest that TG is able to sensitize tumor cells of GCT to TRAIL-induced cell death, perhaps in part through up-regulating the death receptor DR5 and down-regulating the decoy receptor DcR1. These findings provide an additional insight into the design of new treatment modalities for patients suffering from GCT.     

Sensitivity of prostate cells to TRAIL-induced apoptosis increases with tumor progression: DR5 and caspase 8 are key players

BACKGROUND: As advanced prostate cancers are resistant to currently available chemotherapies, we evaluated the cytotoxic effect of TNF-related apoptosis-inducing ligand (TRAIL) and characterized the involvement of its five receptors DR4, DR5, DcR1, DcR2, and osteoprotegerin (OPG) and of the death-inducing signaling complex (DISC)-forming proteins caspase 8 and c-FLIP in prostate cell lines. METHODS: We used six prostate cell lines, each corresponding to a particular stage in prostate tumorigenesis, and analyzed TRAIL sensitivity in relation to TRAIL receptors' expression. RESULTS: TRAIL sensitivity was correlated with tumor progression and DR5 expression levels and apoptosis was exclusively mediated by DR5. DcR2 was significantly more abundant in tumor cells than in non-neoplastic ones and may contribute to partial resistance to TRAIL in some prostate tumor cells. Conversely, non-tumoral cells secreted high levels of OPG, which can protect them from apoptosis. Finally, caspase 8 expression levels were as DR5 directly correlated to TRAIL sensitivity in prostate tumor cells. CONCLUSION: TRAIL-induced apoptosis is closely related to the balanced expression of its different receptors in prostate cancer cells and their modulation could be of potential clinical value for advanced tumor treatment.     

Regulation of the resistance to TRAIL-induced apoptosis as a new strategy for pancreatic cancer

BACKGROUND: Tumor necrosis factor-related, apoptosis-inducing ligand (TRAIL) is a potent inducer of apoptosis in a wide variety of tumor cells, but it does not cause toxicity in the majority of normal cells. Therefore, TRAIL could become a suitable agent for anticancer therapies. However, a number of tumor cell lines are known to be resistant to TRAIL-induced apoptosis. The purpose of this study was to determine the mechanisms of resistance to TRAIL in pancreatic cancer cells. METHODS: In human pancreatic cancer cell lines, the sensitivity to TRAIL-induced apoptosis was tested. The expression of TRAIL receptors (DR4, DR5, DcR1, and DcR2) and the expression of death signal-transducing proteins were investigated. In the TRAIL-resistant pancreatic cancer cells, effects of cycloheximide, a protein synthesis inhibitor, on death signal-transducing proteins were tested. Finally, the effects of the combined treatment with cycloheximide and TRAIL on the induction of apoptosis and on the expression of death signal-transducing proteins were examined. RESULTS: Pancreatic cancer cells responded to TRAIL in a different way. Resistant cell lines, AsPC-1, Suit-2, and CFPAC-1, expressed higher levels of FLIP-S protein, one of the splice variants of FLIP. Cycloheximide reduced the expression of FLIP in the resistant cells. Combined treatment with cycloheximide and TRAIL induced cleaved forms of caspases and simultaneously restored the sensitivity to TRAIL-induced apoptosis in the resistant cells. CONCLUSIONS: Pancreatic cancer cells are resistant to TRAIL-induced apoptosis via strong expression of the anti-apoptotic protein FLIP-S. Suppression of FLIP-S by cycloheximide restored sensitivity to TRAIL-induced apoptosis in resistant cancer cells. These findings may provide useful information for the development of TRAIL-based therapeutic strategies aimed at restoring the functionality of apoptotic pathways in pancreatic cancer cells.     

Sensitization of human renal cell carcinoma cell lines to TRAIL-induced apoptosis by anthracyclines

BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a new member of the tumor necrosis factor family. The present study investigated whether anthracyclines enhance TRAIL-induced apoptosis and cytotoxicity in renal cell carcinoma (RCC) cells. METHODS: Cytotoxicity was measured using the microtiter assay. Apoptosis was monitored using DNA ladder analysis. Caspase activity was determined using a quantitative colorimetric assay. RESULTS: Treatment of ACHN and Caki-1 human RCC lines with TRAIL, in combination with subtoxic concentrations of epirubicin (EPI) or pirarubicin (THP), enhanced induction of apoptosis and cytotoxicity. Sequential treatment with EPI followed by TRAIL induced significantly more cytotoxicity than the inverse treatment. The combined cytotoxicity of TRAIL and EPI was significantly inhibited by the TRAIL-neutralizing fusion protein DR5:Fc, although EPI did not affect the mRNA expression of DR4, DR5, DcR1 or DcR2. The combination treatment with TRAIL and EPI activated caspase-6 and -3, which were downstream molecules of the death receptor. Furthermore, the combined cytotoxicity of TRAIL and EPI was almost completely inhibited by Z-VAD-FMK, and partly inhibited by Ac-DMQD-CHO. CONCLUSION: These findings indicate that anthracyclines sensitize RCC cells to TRAIL-induced apoptosis and cytotoxicity through activation of caspases, suggesting that TRAIL, in combination with anthracyclines, has a therapeutic potential in the treatment of RCC.     

肿瘤坏死因子相关诱导凋亡配体受体mRNA在肝癌中的表达及其意义

目的 探讨肿瘤坏死因子相关诱导凋亡配体的4种受体DR4、DR5、DcR1、DcR2在肝细胞癌肝组织中的表达状况。方法 应用半定量逆转录-聚合酶链反应（RT-PCR）方法检测40例人肝细胞癌组织、相应癌旁肝组织、23例正常人肝组织中DR4、DR5、DcR1、DcR2的mRNA表达率及表达水平。结果 （1）40例肝癌组织、癌旁组织、23例正常肝组织DR4、DR5的mRNA的表达水平差异无统计学意义（P〉0．05）；（2）40例癌旁组织、23例正常肝组织DcR1、DcR2表达水平明显高于40例肝癌组织（P〈0．05）；（3）DR4和DR5mRNA在肝细胞癌组织中表达水平与患者的年龄，肿瘤大小，有无包膜，分级程度，AFP水平，HBsAg，有无肝硬化有关系。结论 肝癌组织中存在TRAIL受体的表达，与其在正常肝组织中的表达差异有统计学意义（P〈0．05）；DR4、DR5表达水平与肝癌的病理状况有关系。     

Effects of sequential treatments with chemotherapeutic drugs followed by TRAIL on prostate cancer in vitro and in vivo

BACKGROUND: Tumor necrosis factor related apoptosis-inducing ligand/Apo2 ligand (TRAIL/Apo-2L) is a novel anticancer agent, capable of inducing apoptosis preferentially in tumor and transformed cells. TRAIL-R1/death receptor (DR)4 and TRAIL-R2/DR5 are members of the tumor necrosis factor (TNF) receptor family, and can be activated by the TRAIL. We examined the clinical potential of chemotherapeutic drugs and TRAIL for the treatment of prostate cancer. METHODS: Prostate and bladder cancer cells were exposed to chemotherapeutic drugs (paclitaxel, vincristine, vinblastine, etoposide, doxorubicin, and camptothecin) and TRAIL. Cell viability was measured by sodium 3'[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) assay; expressions of death receptors and Bcl-2 family members were measured by Western blotting, ELISA and ribonuclease protection assay. PC-3 tumor cells xenografted athymic nude mice were exposed to chemotherapeutic drugs and TRAIL, either alone or in combination, to measure tumor growth and survival of mice. Apoptosis was measured by annexin V-FITC/propidium iodide staining, and terminal deoxynucleotidyltransferase-mediated nick end labeling assay. Caspase-3 activity was measured by the Western blotting and immunohistochemistry. RESULTS: TRAIL induced apoptosis with varying sensitivity. Chemotherapeutic drugs (paclitaxel, vincristine, vinblastine, etoposide, doxorubicin, and camptothecin) significantly augmented TRAIL-induced apoptosis in cancer cells through up-regulation of DR4, DR5, Bax, and Bak, and induction of caspase activation. Mitochondrial pathway enhanced the synergistic interactions between drugs and TRAIL. The sequential treatment of mice with chemotherapeutic drugs followed by TRAIL induced caspase-3 activity, and apoptosis, inhibited angiogenesis, completely eradicated the established tumors, and enhanced survival of mice. CONCLUSIONS: Chemotherapeutic drugs can be used to enhance the therapeutic potential of TRAIL in prostate cancer.