Smac合成肽靶向下调凋亡抑制蛋白XIAP提高胰腺癌细胞化疗敏感性

目的:探讨包含目的蛋白功能结构域的Smac合成肽能否增强胰腺癌细胞的化疗药物敏感性及其作用机制.方法:化学合成SmacN7细胞可穿透融合多肽,共沉淀实验观察SmacN7细胞穿透肽与胰腺癌Panc-1细胞内的XIAP的相互作用,应用流式细胞术检测SmacN7细胞穿透肽与顺铂、5-FU联用对Panc-1细胞凋亡的影响,MTT法检测SmacN7细胞穿透肽应用前后Panc-1细胞的化疗药物敏感性.结果:SmacN7融合多肽能与内源性XIAP结合,明显下调Panc-1细胞XIAP表达水平,显著增强顺铂或5-FU诱导的Panc-1细胞凋亡,使其对顺铂、5-FU的药物半数抑制浓度(IC50)分别降低1.98倍、2.62倍.结论:应用包含目的蛋白功能结构域的Smac合成肽能靶向下调胰腺癌Panc-1细胞XIAP表达,显著提高其化疗敏感性,为胰腺癌的生物治疗协同化疗提供了新思路.     

吲哚美辛诱导食管癌EC109细胞凋亡的Smac依赖性机制

目的:研究Smac表达下调对吲哚美辛诱导的食管癌EC109细胞凋亡的影响,并探索其内在分子机制。方法:使用Smac-siRNA脂质体法转染食管癌EC109细胞,将细胞分为空白对照组, siRNA-control阴性对照组和siRNA-Smac组。使用不同浓度的吲哚美辛处理各组细胞,MTT检测细胞活力变化,流式细胞术检测其对细胞凋亡的影响,Western blot法检测Caspase-9、3以及XIAP、survivin表达情况。结果:采用不同浓度吲哚美辛处理后,细胞活力明显受到抑制;Smac siRNA可明显降低Smac在RNA水平和蛋白水平的表达;吲哚美辛可引起各组凋亡率明显增加,单纯导入siRNA-Smac片段并不能引起细胞凋亡变化,siRNA-Smac联合药物能明显降低EC109细胞凋亡率（P＜0.05）。在蛋白水平,siRNA-Smac组的survivin表达无明显变化,XIAP表达明显增强;Caspase-9及Caspase-3的活性片段明显表达减弱（P＜0.05）。结论:NSAIDs药物吲哚美辛可诱导食管癌EC109细胞凋亡,这种作用一定程度上依赖于Smac的正常表达;Smac表达降低后其对XIAP的抑制减弱,Caspase-9和Caspase-3的活化受到抑制,而survivin在其中并不起决定性作用。     

凋亡抑制蛋白XIAP和促凋亡因子Smac在胰腺癌化疗抵抗中的调控作用

Objective： To investigate the relation of X-linked inhibitor of apoptosis （XIAP） and second mitochondria-derived activator of caspase （Smac） signaling pathway to chemoresistance in human pancreatic cancer Panc-1 and BXPC-3 cells. Methods： Apoptosis and the changes of XIAP expression in permeabilized cells induced by cisplatin and 5-fluorouracil （FU） were measured by flow cytometry. The cytosolic expression of XIAP, Smac and caspase-3 was detected by Western blot. A recombinant plasmid vector pEGFP-N1/Smac was constructed and transfected into of Pancol cells. The effect of cytosolic overexpression of Smac on apoptosis of Panc-1 cells was evaluated by flow cytometry. Results： Panc-1 was more resistant to cisplatin or 5-FU induced apoptosis than BXPC-3. Western blot revealed that chemoresistant Panc-1 highly expressed XIAP, and increased cytosolic expression of Smac might be responsible for the marked down-regulation of XIAP in chemo-sensitive BXPC-3 cells after exposure to cisplatin or 5-FU. Furthermore, cytosolic overexpression of Smac could significantly down-regulate the levels of XIAP and promote the activity of caspase-3, as well as sensitize Panc-1 cells to anticancer drug-induced apoptosis. Conclusion： Anticancer drug-induced apoptosis requires mitochondrial release of Smac and downregulation of XIAP, which may be an important determinant of chemo-sensitivity in pancreatic cancer cells. Up-regulation of cytosolic expression of Smac may act as an effective modifying signal to overcome apoptosis resistance to chemotherapy in pancreatic cancer cells.     

小檗碱诱导耐药急性淋巴细胞白血病细胞株EU-4凋亡及其机制

目的 探讨小檗碱对耐药急性淋巴细胞白血病细胞株EU-4的凋亡诱导作用及其机制.方法 0、10、1 00 μmol／L小檗碱作用EU-4细胞72 h,采用流式细胞术检测细胞凋亡,免疫印迹法检测Caspase-3、PARP及X连锁凋亡抑制蛋白（XIAP）的蛋白表达,比色法检测Caspase-3的活性变化,基因沉默技术观察降低XIAP表达对于细胞凋亡的影响.结果 0、10、100μmol／L小檗碱作用EU-4细胞72 h后凋亡率分别为（9.08±1.20）％、（22.36±2.16）％、（59.81±4.17）％,呈剂量-效应关系.凋亡过程中Caspase-3的活性增强,分别为1.70±0.25、1.92±0.10、2.89±0.25.小檗碱抑制EU-4细胞XIAP的表达（P＜0.05）,并呈剂量和时间依赖关系.单纯下调XIAP蛋白的表达引起细胞凋亡,对照siRNA转染组和XIAP siRNA转染组细胞凋亡率分别为（9.23±1.66）％和（22.15±0.63）％.结论 小檗碱可以诱导急性淋巴细胞白血病EU-4细胞凋亡,XIAP下调引起的Caspase-3的激活参与了EU-4细胞的凋亡.     

凋亡抑制蛋白XIAP基因对A549细胞凋亡和化疗敏感性的影响

背景与目的X连锁凋亡抑制蛋白(X-linked inhibitor of apoptosis protein,XIAP)是新发现的一个IAP家族中的主要成员,是IAP家族中最强的凋亡抑制因子,它可直接抑制caspases并可多途径调节细胞凋亡。XIAP基因在大多数的肿瘤细胞株中过表达,其表达与肿瘤的进展、复发、预后以及肿瘤化疗的耐药密切相关。研究通过RNAi方法下调非小细胞肺癌(NSCLC)细胞NIC-A549的XIAP基因表达后,研究XIAP siRNA特异序列在NSCLC细胞凋亡和化疗敏感性方面的作用。方法应用半定量RT-PCR法检测A549细胞中XIAP mRNA基因的表达,设计并构建XIAP干扰性小RNA(small interfering RNA,siRNA)序列的表达载体,转染siRNA载体至A549中。荧光纤维镜确定转染效率,MTT法测定细胞增殖率及化疗药物对细胞杀伤率,流式细胞仪测定细胞凋亡率。结果酶切和DNA测序证实XIAP siRNA构建成功。荧光纤维镜显示阳性转染组及阴性转染组的细胞转染效率无差异。半定量RT-PCR法示阳性转染组较阴性转染组、未转染组细胞XIAP mRNA表达明显降低;与对照组相比,顺铂对阳性转染组XIAP mRNA表达的抑制作用明显增强、阳性转染组细胞增殖在24h、48h、72h、96h明显受抑制;细胞杀伤率、凋亡率明显增加。结论XIAP基因在NSCLC中表达增高,可抑制NSCLC细胞凋亡,导致NSCLC化疗耐药。XIAP siRNA序列可特异性地抑制NSCLC细胞增长,下调XIAP基因的表达,促进细胞凋亡,增加NSCLC化疗敏感性。XIAP siRNA序列有可能成为NSCLC治疗的靶标。     

XIAP siRNA对TRAIL诱导结肠癌细胞SW620凋亡能力的影响

 目的
研究XIAP siRNA对肿瘤坏死因子相关的凋亡诱导配体(Tumor Necrosis Factor-related Apoptosis-Inducing Ligand,TRAIL)诱导结
肠癌细胞SW620凋亡的影响。方法SW620细胞分为转染XIAP siRNA组、空转染对照组或者siRNA阴性对照组,然后给予TRAIL处理。XIAP
表达水平的变化、细胞增殖抑制、Caspase-3活性分别由Western blot、MTT法和Caspase-3荧光测定来检测。切割PARP的表达水平由
Western blot来测定。结果XIAP siRNA转染以后显著下调XIAP蛋白表达水平。和空转染对照组、siRNA阴性对照组相比,XIAP siRNA
显著增强10、100、1 000 ng/ml等浓度的TRAIL作用以后SW620细胞的增殖抑制、Caspase-3活性和激活PARP。结论 XIAP siRNA能显
著增强TRAIL诱导结肠癌细胞SW620的凋亡。     

Smac基因过表达对胃癌细胞株 MKN-45 化疗敏感性的影响

背景与目的:细胞凋亡异常是肿瘤细胞产生耐药性的关键因素之一. Smac(second mitochondria-derived activator of caspases,Smac或称 DIABLO)是新近发现的一种凋亡调节基因,在介导化疗药物诱导肿瘤细胞凋亡中起重要作用.本研究旨在观察 Smac基因过表达对胃癌细胞株化疗敏感性的影响.方法:采用脂质体 GeneSHUTTLE-40介导的方法,将 Smac基因转入胃癌细胞 MKN-45, RT-PCR和 Western blot法检测癌细胞中 Smac的表达;选用顺铂 (1、 5、 10 μ g/ml)、丝裂霉素 (0.1、 1、 10 μ g/ml)和姜黄素 (10、 20、 40 μ mol/L)分别处理转染前后的胃癌细胞,四甲基偶氮唑蓝( MTT)比色法检测细胞增殖活性,倒置显微镜下观察细胞形态变化并摄影, Annexin V-FITC和碘化丙啶双染色,流式细胞仪检测细胞凋亡.结果:同未转染对照组比较,转染外源性 Smac基因后 MKN-45细胞 Smac mRNA和蛋白表达水平显著增高( P< 0.01);各浓度顺铂、丝裂霉素和姜黄素处理 24 h后,细胞生长抑制率分别 增加 10.10%～ 23.80%( P< 0.01)、 10.01%～ 15.86%( P< 0.01)、 11.28%～ 22.12%( P< 0.01),细胞明显变圆、折光增强、漂浮细胞增多,细胞凋亡率分别增加 6.7%～ 20.2%( P< 0.01)、 5.4%～ 13.2%( P< 0.01)、 10.6%～ 20.1%( P< 0.01).结论:转染外源性 Smac基因并使其在胃癌细胞中过表达,能提高 MKN-45对化疗药物的敏感性.     

siRNA介导的STAT3基因沉默对宫颈癌HeLa细胞凋亡和化疗敏感性的影响

目的:应用siRNA介导的STAT3基因沉默,研究其对HeLa细胞凋亡和化疗敏感性的影响.方法:体外合成靶向STAT3的siRNA-1和siRNA-2,并用脂质体转染HeLa细胞,RT-PCR检测干扰STAT3 mR-NA敲减的效率,蛋白质印迹法检测敲减后STAT3蛋白的表达;通过记录生长曲线观察干扰后细胞的增殖情况.用AnnexinV/PI双染,结合流式细胞仪检测细胞早期凋亡率.MTT法检测肿瘤细胞对几种化疗药物的敏感性.结果:siRNA使STAT3表达下调,mRNA水平抑制率为74.8%和60.4%;蛋白表达水平抑制达68.0%和59.0%.干扰后HeLa细胞增殖缓慢,早期凋亡率明显增加.对顺铂、长春瑞滨和吉西他滨有增敏作用.结论:siRNA介导的STAT3沉默可以抑制宫颈癌HeLa细胞的增殖,诱导凋亡,增加对化疗药物的敏感性,可望成为一种新的治疗策略.     

白血病K562细胞XIAP表达RNAi下调对凋亡及化疗敏感性影响的研究

目的:通过RNAi下调K562细胞X染色体连锁的凋亡抑制蛋白(XIAP)的表达,观察XIAP下调后细胞凋亡及对化疗药物敏感性的变化情况。方法:K562细胞分为3组,实验组和阴性对照组分别用XIAP siRNA及阴性对照siR-NA转染,空白对照组不做任何转染处理。用实时荧光定量PCR和蛋白质印迹法检测转染后各组细胞XIAP mRNA及蛋白的表达,CCK-8法检测各组细胞对阿糖胞苷和依托泊苷敏感性的变化,流式细胞仪和Hochest染色法检测各组细胞加入不同化疗药物后细胞的凋亡情况。结果:转染后48h,实验组XIAP mRNA及蛋白表达量较阴性对照组分别下降约70.0%和60.0%,P<0.05;实验组细胞对依托泊苷和阿糖胞苷的敏感性分别提高2.77和2.28倍,P<0.05;转染siR-NA 48h后,实验组与阴性对照组、空白对照组间凋亡率差异无统计学意义,P>0.05;转染siRNA 6h后加入依托泊苷孵育48h,实验组凋亡率(41.3±1.6)%较阴性对照组(34.3±1.9)%和空白对照组(30.6±1.7)%明显增加;加入阿糖胞苷孵育48h,实验组凋亡率(47.4±1.1)%较阴性对照组(37.0±1.8)%和空白对照组(35.5±1.7)%明显增加,P<0.05。结论:XIAP siRNA能特异性下调K562细胞的XIAP mRNA和蛋白质水平的表达,提高K562细胞对依托泊苷和阿糖胞苷的敏感性,同时伴化疗药物诱导的细胞凋亡增强。     

蛋白激酶B抑制线粒体Smac释放与卵巢癌顺铂耐药的关系

目的 探讨蛋白激酶B(Akt)和线粒体促凋亡蛋白(Smac)在顺铂诱导的卵巢癌细胞凋亡中的关系及Akt在卵巢癌顺铂耐药中的分子机制.方法 应用Western blot检测顺铂作用前后卵巢癌顺铂敏感细胞OV2008、A2780s和顺铂耐药细胞C13*、A2780cp中Smac含量.将Smac siRNA和Smac N7多肽分别导人0V2008和C13*细胞中,应用流式细胞仪测定细胞的凋亡率,观察稳定转染Akt2的A2780s(A2780s-AAkt2)细胞和转染Akt1/2siRNA的C13*细胞对顺铂耐药性的改变.结果顺铂能导致OV2008、A2780s细胞线粒体释放Smac,并引起细胞凋亡(P＜0.05);但在C13*和A2780cp细胞中无此反应(P＞0.05).转染Smac siRNA后的0V2008细胞,其Smac表达降低,对顺铂的耐药性增加;转染Smac N7多肽能增加C13*细胞对顺铂的敏感性;Akt2过度表达可抑制A2780s细胞Smac释放,并对顺铂产生了耐药性;应用Akt1/2 siRNA后可下调C13*细胞中Akt1/2的表达,使C13*细胞对顺铂的敏感性增加.结论 顺铂对卵巢癌细胞的杀伤在一定程度上是通过线粒体释放Smac所致;Akt抑制了线粒体Smac释放与卵巢癌化疗耐药部分相关.     

TFPI-2基因对Panc-1细胞凋亡的影响

[目的]研究TFPI-2基因对胰腺癌细胞系Panc-1细胞增殖及凋亡的影响。[方法]测定Panc-1-TFPI-2、Panc-1-V和Panc-1-P三组细胞的生长曲线．DNA片段化实验检测细胞凋亡，并用流式细胞仪分析三组细胞的细胞增殖、细胞周期情况。[结果]Panc-1-TFPI-2细胞同Panc-1-V和Panc-1-P细胞相比，细胞生长缓慢，细胞生长受到抑制，被阻滞于G0～G1期；DNA片段化实验显示Panc-1-TFPI-2细胞呈现凋亡细胞特有的“梯状”条带．而Panc-1-V和Panc-1-P细胞无明显“梯状”条带：流式细胞仪分析显示早期Panc-1-TFPI-2细胞凋亡率（6．93％± 0．53％）较Panc-1-V（3．01％± 0．39％）和Panc-1-P细胞凋亡率（3．52％±0．41％）增加，有显著性差异（P〈0．05）。[结论]TFPI-2能够抑制胰腺癌细胞生长、诱导胰腺癌细胞凋亡．可能具有抑制肿瘤细胞增殖的作用。     

Mechanisms of TRAIL and gemcitabine induction of pancreatic cancer cell apoptosis

The aim of this study was to investigate induction of apoptosis by the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and gemcitabine in the pancreatic cancer cell line SW1990. The sensitivity of SW1990 cells to TRAIL and/or gemcitabine-induced apoptosis and the rate of apoptosis were assessed by MTT assay and flow cytometry, respectively. We used Hoechst 33342 staining to observe apoptotic morphology and expression levels of proteins were analyzed by Western blottin. Growth inhibition and apoptosis rates on treatment with the combination of TRAIL and gemcitabine were significantly higher than with each drug alone (p<0.05). Pancreatic cancer cells exhibited a typical apoptosis morphology after treatment with TRAIL or gemcitabine. The levels of cellular apoptosis-associated proteins such as Smac/DIABLO, Cyto C, and the activated fragment of caspase-3 (P17) increased, but the expression of XIAP was significantly decreased after 24 h (p<0.05). SW1990 cells responded to TRAIL and/or gemcitabine-induction of apoptosis in a time and concentration-dependent manner. The mechanism of the apoptosis-sensitization effect appeared associated with significant up-regulation of Smac/DIABLO and cytochrome C, down-regulation of XIAP, and activation of caspase-3.     

Overexpression of neuropilin-1 promotes constitutive MAPK signalling and chemoresistance in pancreatic cancer cells

Neuropilin-1 (NRP-1) is a novel co-receptor for vascular endothelial growth factor (VEGF). Neuropilin-1 is expressed in pancreatic cancer, but not in nonmalignant pancreatic tissue. We hypothesised that NRP-1 expression by pancreatic cancer cells contributes to the malignant phenotype. To determine the role of NRP-1 in pancreatic cancer, NRP-1 was stably transfected into the human pancreatic cancer cell line FG. Signal transduction was assessed by Western blot analysis. Susceptibility to anoikis (detachment induced apoptosis) was evaluated by colony formation after growth in suspension. Chemosensitivity to gemcitabine or 5-fluorouracil (5-FU) was assessed by MTT assay in pancreatic cancer cells following NRP-1 overexpression or siRNA-induced downregulation of NRP-1. Differential expression of apoptosis-related genes was determined by gene array and further evaluated by Western blot analysis. Neuropilin-1 overexpression increased constitutive mitogen activated protein kinase (MAPK) signalling, possibly via an autocrine loop. Neuropilin-1 overexpression in FG cells enhanced anoikis resistance and increased survival of cells by > 30% after exposure to clinically relevant levels of gemcitabine and 5-FU. In contrast, downregulation of NRP-1 expression in Panc-1 cells markedly increased chemosensitivity, inducing > 50% more cell death at clinically relevant concentrations of gemcitabine. Neuropilin-1 overexpression also increased expression of the antiapoptotic regulator, MCL-1. Neuropilin-1 overexpression in pancreatic cancer cell lines is associated with (a) increased constitutive MAPK signalling, (b) inhibition of anoikis, and (c) chemoresistance. Targeting NRP-1 in pancreatic cancer cells may downregulate survival signalling pathways and increase sensitivity to chemotherapy.     

Disturbed balance of expression between XIAP and Smac/DIABLO during tumour progression in renal cell carcinomas

Dysregulation of apoptosis plays an important role in tumour progression and resistance to chemotherapy. The X-linked inhibitor of apoptosis (XIAP) is considered to be the most potent caspase inhibitor of all known inhibitor of apoptosis-family members. Only recently, an antagonist of XIAP has been identified, termed Smac/DIABLO. To explore the relevance of antiapoptotic XIAP and proapoptotic Smac/DIABLO for tumour progression in renal cell carcinomas (RCCs), we analysed XIAP and Smac/DIABLO mRNA and protein expression in the primary tumour tissue from 66 RCCs of all major histological types by quantitative real-time PCR, Western blot and ELISA. X-linked inhibitor of apoptosis and Smac/DIABLO mRNA expression was found in all RCCs. Importantly, the relative XIAP mRNA expression levels significantly increased from early (pT1) to advanced (pT3) tumour stages (P=0.0002) and also with tumour dedifferentiation (P=0.04). Western blot analysis confirmed the tumour stage-dependent increase of XIAP expression on the protein level. In contrast, mRNA and protein expression levels of Smac/DIABLO did not significantly change between early and advanced tumour stages or between low and high tumour grades. Consequently, the mRNA expression ratio between antiapoptotic XIAP and proapoptotic Smac/DIABLO markedly increased during progression from early (pT1) to advanced (pT3) tumour stages. Moreover, RCCs confined within the organ capsule (pT1 and pT2) exhibited a significantly lower XIAP to Smac/DIABLO expression ratio when compared with RCCs infiltrating beyond the kidney (pT3; P=0.01). Thus, our investigation demonstrates that the delicate balance between XIAP and Smac/DIABLO expression is gradually disturbed during progression of RCCs, resulting in a relative increase of antiapoptotic XIAP over proapoptotic Smac/DIABLO, thereby probably contributing to the marked apoptosis resistance of RCC.     

Coexistence of high levels of apoptotic signaling and inhibitor of apoptosis proteins in human tumor cells: implication for cancer specific therapy

It is well known that dysfunction of the apoptotic pathway confers apoptosis resistance and results in a low sensitivity of human cancer cells to therapeutic agents. A novel strategy to overcome the resistance is to target the apoptotic pathway directly. To identify molecular targets in the apoptotic pathway that are differentially regulated in cancer and normal cells, we have examined the levels of apoptotic effectors and inhibitors in human tumor and normal cell lines as well as in cancer and normal tissues. These include three pancreatic cancer lines (BXPC-3, MIA PaCa-2, and Panc-1), four breast cancer cell lines (MDA-MB-231, MDA-MB-435, MDA-MB-361, and MCF-7), and colon carcinoma line (SW620). Additionally, breast carcinoma tissue specimens were examined. Compared with normal human fibroblast and mammary epithelial cell lines, we detected high basal levels of caspase-3 and caspase-8 activities and active caspase-3 fragments in the tumor cell lines and cancer tissues in the absence of apoptotic stimuli. Furthermore, the tumor cells expressed high levels of survivin and XIAP, two members of the inhibitor of apoptosis (IAP) protein family. When the activity of these IAPs was blocked by expression of dominant-negative mutant survivin (survivinT34A) and XIAP-associated factor 1, respectively, apoptosis was induced in tumor but not normal cell lines. Moreover, down-regulation of both survivin and XIAP significantly enhanced tumor-cell apoptosis as compared with inhibition of either survivin or XIAP alone. These results suggest that up-regulated IAP expression counteracts the high basal caspase-3 activity observed in these tumor cells and that apoptosis in tumor cells but not normal cells can be induced by blocking IAP activity. Therefore, IAPs are important molecular targets for the development of cancer-specific therapeutic approaches.     

DNMT3a通过STAT3及RAD51影响胰腺癌细胞对奥沙利铂敏感性的研究

目的:检测DNMT3a在胰腺癌细胞中的表达及对奥沙利铂（oxaliplatin，OXA）敏感性的影响，探讨DNMT3a对胰腺癌细胞奥沙利铂敏感性影响的机制。方法:MTT法检测奥沙利铂对人胰腺癌Panc-1细胞的增殖影响，及下调DNMT3a对Panc-1细胞奥沙利铂敏感性的影响。Western blot检测siDNMT3a对DNMT3a蛋白表达的影响，检测奥沙利铂及下调DNMT3a对γ-H2AX、RAD51、p-STAT3和STAT3蛋白表达的影响。流式细胞仪检测奥沙利铂及联合下调DNMT3a对Panc-1细胞凋亡的影响。结果:奥沙利铂能够以浓度依赖方式抑制胰腺癌Panc-1细胞的增殖。奥沙利铂能够引起DNA损伤、γ-H2AX上调及RAD51增高，同时引起STAT3通路的一过性活化。下调DNMT3a表达能够明显增加Panc-1细胞对奥沙利铂的敏感性，抑制STAT3一过性活化，并抑制RAD51表达，促进DNA损伤，进而增加奥沙利铂诱导Panc-1细胞的凋亡。结论:下调DNMT3a表达能够通过抑制STAT3活化及增加DNA损伤增加胰腺癌细胞对奥沙利铂的敏感性，DNMT3a有望成为胰腺癌新的治疗靶点。     

肿瘤坏死因子相关的凋亡诱导配体对胰腺癌细胞抗肿瘤作用的研究

Objective To investigate the antitumor effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)gene transfection mediated by adenovirus into human pancreatic carcinoma cell line Panc-1, and the mechanisms involved in this effect. Methods TRAIL gene was transfected into pancreatic cancer cell line Panc-1 by an adenovirus vector (Ad-TRAIL).Level of TRAIL mRNA expression was determined using RT-PCR, and TRAIL protein synthesis was evaluated with Western blot. Cell-growth activities were determined by MTT assay. The bystander effect was observed by co-culturing the Panc-1cells with the transfected TRAIL gene at different ratios. Apoptosis in pancreatic cancer cells was detected by flow cytometry.Procaspase-8 and procaspase-3 were determined by Western blot. Results The stable overexpression of TRAIL was detected in Panc-1 cells transfected by Ad-TRAIL. Ad-TRAIL significantly inhibited of cell viability of Panc-1 cells. Furthermore,co-culture of cancer cells transfected with TRAIL with that nontransfected resulted in the cell death of both cells by bystander effect. Moreover, the percentage of apoptotic cells was significantly higher in the Ad-TRAIL-treatment group compared to the control groups (P ＜ 0.01). And there was a diminished amount of procaspase-8 and procaspase-3 after infection with Ad-TRAIL. Conclusion The overexpression of TRAIL gene in Panc-1 cells by Ad-TRAIL exerts its antitumor effects, and themechanisms involved in this effect may be proapoptosis and bystander effect.