胃癌细胞多药耐药相关基因的表达与其侵袭转移能力的相关性研究

目的探讨胃癌细胞株BGC-823、SGC-7901的多药耐药相关基因的表达与其侵袭转移能力的关系。方法采用实时荧光定量PCR技术检测胃癌细胞株BGC-823、SGC-7901的多药耐药相关基因(包括ABCB1、MMP2、CDH1、CD44)的mRNA表达水平。采用细胞划痕实验、Transwell迁徙实验评价两株胃癌细胞的侵袭转移能力,进而探讨胃癌细胞多药耐药相关基因的表达与侵袭转移能力的关系。结果荧光定量PCR实验发现胃癌细胞株BGC-823的ABCB1、CDH1、CD44基因表达较SGC-7901高,而MMP2基因的表达在SGC-7901中较高。细胞划痕实验及Transwell迁徙实验显示胃癌细胞株BGC-823的迁徙能力比SGC-7901强。结论胃癌细胞的多药耐药与侵袭转移有一定的关系,CD44的高表达在胃癌细胞的侵袭转移中可能起主要作用。     

大蒜素对人胃癌细胞SGC-7901及BGC-823 G2/M期的阻滞调节机制

目的:研究大蒜素对人胃癌细胞SGC-7901及BGC-823G2/M期阻滞作用及其调节机制.方法:应用MTT法测定大蒜素对人胃癌细胞株SGC-7901和BGC-823细胞增殖抑制率及72h的IC50.通过流式细胞仪检测IC50浓度的大蒜素对SGC-7901和BGC-823细胞周期的影响.应用免疫组化染色检测大蒜素作用前后SGC-7901和BGC-823细胞CDC2和CyclinB蛋白表达.结果:不同浓度的大蒜素可以抑制人胃癌细胞株SGC-7901和BGC-823的增殖,且随着大蒜素浓度的增大,抑制率逐渐增高.大蒜素抑制SGC-7901细胞增殖50%的药物浓度(IC50):72h为23mg/L;大蒜素抑制BGC-823细胞增殖50%的药物浓度(IC50):72h为35mg/L.大蒜素作用于两种细胞,其细胞周期均发生了明显的变化,主要表现为G0/G1期细胞减少,G2/M期细胞增多(SGC-7901细胞24,48hvs对照:26.47±2.54%,28.88±2.75%vs24.30±2.74%,P<0.01;BGC-823细胞24,48hvs对照:22.78±1.45%,24.87±1.61%vs20.32±1.34%,P<0.01),S期细胞无明显变化.未经大蒜素处理的两种细胞,CDC2和CyclinB蛋白表达均为阳性,大蒜素处理后,CDC2和CyclinB蛋白表达下降.SGC-7901细胞经23mg/L大蒜素处理后,CDC2蛋白相对阳性表达率为87.2%;CyclinB蛋白相对阳性表达率为59.3%.BGC-823细胞CDC2蛋白在35mg/L大蒜素作用后,相对阳性表达率为84.4%;CyclinB蛋白相对阳性表达率为62.8%,与对照组相比均有显著性差异(P<0.01).结论:大蒜素使人胃癌细胞株SGC-7901和BGC-823停滞于G2/M期,其机制是通过CDC2和CyclinB蛋白表达下降实现的.     

PTEN基因表达与胃癌细胞侵袭力的相关性研究

目的探讨PTEN基因mRNA表达与胃癌细胞体外侵袭力的关系。方法采用Boyden小室法测定四种胃癌细胞(SGC-7901、BGC-823、M GC-803、HGC-27)的体外侵袭力、运动力,RT-PCR法检测四种胃癌细胞的PTEN基因mRNA表达水平。结果胃癌细胞体外侵袭力为HGC-27(48±2)、M GC-803(28±2)、BGC-823(30±3)、SGC-7901(13±2);PTEN基因mRNA表达水平为SGC-7901(0.336±0.079)、BGC-823(0.232±0.063)、M GC-803(0.228±0.056)、HGC-27(0.113±0.047);两两比较,P<0.01,>0.05,<0.05。相关分析显示,胃癌细胞体外侵袭力随PTEN基因mRNA表达增高而降低,PTEN基因mRNA表达及胃癌细胞体外侵袭力与细胞分化程度相关。结论PTEN基因参与胃癌的发展过程,并与胃癌的部分生物学行为有关,PTEN基因mRNA表达水平对评价胃癌细胞体外运动侵袭力具有重要价值。     

稳定表达绿色荧光蛋白基因胃癌细胞株的构建

目的建立稳定表达绿色荧光蛋白（GFP）的胃癌细胞株。方法将携带GFPcDNA的质粒载体转染至胃癌细胞株SGC-7901内，经过C-418筛选和克隆化培养，用荧光显微镜检测癌细胞荧光表达情况。结果转染GF-PcDNA的胃癌细胞用G418筛选及克隆化培养后，再经150d（50代）培养，96％高表达GFP。将SGC-7901-GFP细胞株接种于裸鼠皮下，成瘤良好。结论成功建立了稳定表达GFP的胃癌细胞株SCC-7901-GFP。     

靶向抑制胃癌细胞中TROP2基因的表达对胃癌细胞增殖及凋亡的影响研究

目的探讨RNA干扰肿瘤相关钙信号传导因子2(TROP2)基因的表达对胃癌细胞增殖及凋亡的影响及机制。方法以人胃黏膜正常细胞GES-1作为对照,RT-PCR检测人胃癌SGC-7901、MNK-28、BGC-823细胞中TROP2 mRNA表达;TROP2 siRNA、Control siRNA转染SGC-7901细胞,不作任何处理的细胞作为空白对照组,48 h后Western blotting检测TROP2、Ki67、Cleaved caspase3、β-catenin、Cyclin D1蛋白表达;CCK8实验和流式细胞仪分别检测细胞的增殖及凋亡情况。结果 TROP2 mRNA在人胃癌SGC-7901、MNK-28、BGC-823细胞表达均显著高于GES-1细胞(P0.01),TROP2基因在SGC-7901细胞中的表达最高,选择作为后续的研究对象;转染TROP2 siRNA后TROP2蛋白表达显著降低(P0.01);与对照组及Control-siRNA组比较,TROP2-siRNA组细胞存活率及Ki67、β-catenin、Cyclin D1蛋白表达显著降低,细胞凋亡率及Cleaved caspase3蛋白表达显著升高(P0.01)。结论RNA干扰抑制TROP2基因的表达可降低胃癌细胞的增殖及诱导细胞凋亡,其机制是下调Wnt/β-catenin信号通路。     

双膦酸盐类药物对胃癌细胞生长增殖的作用机制

目的检测双膦酸盐类药物唑来膦酸对胃癌细胞生长增殖的研究机制。方法培养人胃癌细胞株MKN-28、SGC-7901和BGC-823,将细胞分为对照组和药物处理组,MTT法检测10、20、40、80μmol/L唑来膦酸对细胞株的影响。人胃癌细胞株加入10~80μmol/L的唑来膦酸,对照组不加药物,孵育1、3、6、12、24 h后计算不同浓度和时间对细胞的影响;人胃癌细胞株SGC-7901加入40μmol/L的唑来膦酸培养24 h后,用流式细胞仪检测细胞凋亡情况,Western印迹检测半胱氨酸蛋白酶(Caspase)-3、Caspase-9、Bcl-2蛋白的表达。结果 10、20、40、80μmol/L的唑来膦酸作用于胃癌细胞株(BGC-823、SGC-7901、MKN-28),唑来膦酸的半抑制浓度(IC50)为40μmol/L,用10~80μmol/L的唑来膦酸作用于BGC-823、SGC-7901、MKN-28胃癌细胞株1、3、6、12、24 h后,可见唑来膦酸抑制人胃癌细胞的生长且有时间和浓度的依赖性,唑来膦酸对胃癌正常黏膜细胞GES-1无抑制作用;人胃癌细胞SGC-7901经40μmol/L的唑来膦酸作用24 h后,流式细胞仪检测发现唑来膦酸处理组细胞凋亡情况显著高于对照组;经40μmol/L唑来膦酸作用后的人胃癌细胞中Caspase-3、Caspase-9蛋白表达量明显升高,而Bcl-2蛋白表达量与对照组相比明显减少。结论唑来膦酸能抑制胃癌细胞的生长且有时间和剂量依赖性,唑来膦酸可以促进细胞凋亡。     

胃癌细胞对细小病毒H-1敏感性差异的实验研究

目的 探讨不同胃癌细胞株对细小病毒细胞毒作用的敏感性差异及可能的机制。方法共选用HGC27(未分化)、BGC823(未分化)、MKN45(低分化)、AGS(低分化)、SGC7901(中分化)和MKN28(高分化)等6株不同分化状态的胃癌细胞株，用流式细胞仪分析其各自的细胞周期，H-1病毒感染后采用MTT方法检测不同胃癌细胞株对其细胞毒作用的敏感性差异，用RT-PCR来检测H-1病毒中的非结构蛋白基因(NS-1)在6株不同胃癌细胞中的表达。结果 HGC27、BGC823、MKN45、AGS、SGC7901和MKN28等不同分化状态细胞株中，S期细胞的比率分别为24．72％，30．15％，27．10％，29．03％，31．82％和33．73％。其中HGC27细胞对H-1病毒的细胞毒作用敏感；SGC7901细胞其次；MKN45、AGS细胞对H-1病毒的细胞毒作用中等敏感；MKN28细胞对H-1病毒的细胞毒作用不敏感；而BGC823则对H-1病毒的细胞毒作用抵抗。病毒NS-1的mRNA在HGC27、BGC823、MKN45和SGC7901等细胞中的表达水平较高，而在AGS和MKN28中的表达水平却较低。结论 H-1病毒的细胞毒作用在不同的胃癌细胞株中的差异显著。总体上，与高分化细胞株MKN28细胞相比，分化差的细胞对细小病毒H-1的细胞毒作用敏感性增加。其机制至少部分与分化差细胞中病毒NS-1蛋白的产生和积聚能力增高相关。未分化的BGC823细胞对H-1病毒的细胞毒作用抵抗，进一步证实并非所有的肿瘤细胞都对细小病毒的溶胞性作用敏感。     

抑癌基因PTEN与胃癌细胞分化及侵袭力的机制研究

采用Boyden小室法测定三种不同分化胃癌细胞(SGC-7901、BGC-823、MGC-803、HGC-27)的体外侵袭力、运动力,RT-PCR检测胃癌细胞的PTEN mRNA表达水平,Western blot法检测胃癌细胞FAK、P-FAK蛋白表达水平.发现随着细胞分化程度的升高,PTEN mRNA表达明显增多,P-FAK蛋白表达明显减少,细胞侵袭力和运动力亦明显减弱(P＜0.01或P＜0.05),FAK蛋白表达无明显变化.认为PTEN mRNA、P-FAK蛋白表达水平在评价胃癌细胞体外运动侵袭力方面具有重要价值;PTEN基因可能通过FAK蛋白途径影响胃癌的侵袭转移.     

β-arrestin1在胃癌细胞BGC-823中的生物学功能

目的 探讨β-arrestin1对胃癌细胞BGC-823增殖、迁移、侵袭及凋亡能力的影响.方法 用实时定量PCR技术及Western印迹法检测人胃黏膜上皮细胞GES和人胃癌细胞株BGC-823、MKN-28、SGC-7901中β-arrestin1的表达水平.应用RNA干扰技术构建稳定干扰β-arrestin1和阴性对照组(pU6空载体)的BGC-823细胞株.进一步应用细胞计数法、划痕实验、Transwell小室实验及流式细胞术分析干扰β-arrestin1和阴性对照组的BGC-823细胞株的增殖、迁移、侵袭能力及凋亡水平的变化.统计学处理采用t检验.结果 β-arrestin1在GES表达量为0.001±0.001,MKN-28表达量为0.002±0.000,SGC-7901表达量为0.003±0.002,BGC-823中表达量为0.005±0.000.干扰β-arrestin1和阴性对照的BGC-823细胞增殖抑制率分别为-30.2％和100.0％.迁移能力受到抑制,穿过基质膜细胞数分别为126.25±3.24和213.50±6.27(t=0.000,P＜0.01),凋亡率为(41.350±1.053)％和(11.497±0.589)％(t=0.015,P＜0.05).结论 β-arrestin1在胃癌细胞中高水平表达,并且随着胃癌细胞恶性度增高而表达量增加,在BGC-823细胞中干扰β-arrestin1后能抑制细胞的生长、迁移、侵袭,并提高凋亡水平.     

缺氧诱导胃癌细胞SGC-7901中三叶因子3与血管内皮生长因子相互关系研究

目的 探讨在缺氧条件下胃癌细胞SGC-7901中三叶因子3(TFF3)与血管内皮生长因子(VEGF)及缺氧诱导因子(HIF-1α)的相互关系,了解TFF3在胃癌发生发展过程中的作用机制.方法 使用氯化钴( CoCl2)构建胃癌细胞株SGC-7901的缺氧模型.运用携带靶向干扰人类TFF3的pU6 siTFF3和pU6-mock分别转染胃癌细胞株SGC-7901.以嘌呤霉素为筛选药物,建立稳定特异性抑制TFF3的胃癌细胞株.在缺氧环境和常氧环境下培养胃癌细胞株SGC-7901和靶向干扰TFF3后的胃癌细胞株SGC-7901,运用定量PCR、ELISA和Western印迹分析等方法分别测定其TFF3、HIF-1α和VEGF的蛋白和mRNA表达情况.运用免疫荧光法观察在缺氧环境和常氧环境下胃癌细胞株SGC-7901中TFF3、HIF-1α的分布及表达量.结果 CoCl2缺氧处理能诱导胃癌细胞株SGC-7901中H1F-1α、TFF3和VEGF mRNA表达量上升(分别为33.4±1 8、14.8±1.1和15.1±1.2).稳定干扰TFF3的SGC-7901细胞在缺氧诱导下能下调VEGF和HIF-1蛋白的表达.结论 TFF3介导调节了缺氧条件下VEGF和HIF-1的表达,TFF3有可能是潜在的抗血管生成胃癌治疗靶点.     

Effect of NF-κB, survivin, Bcl-2 and Caspase3 on apoptosis of gastric cancer cells induced by tumor necrosis factor related apoptosis inducing ligand

AIM: To study the effect of NF-κB, survivin, Bd-2 and Caspase3 on tumor necrosis factors related apoptosis inducing ligand (TRAIL) induced apoptosis of gastric cancer cells. METHODS: Gastric cancer cells of SGC-7901, MKN28, MKN45 and AGS lines were cultured in PRMI-1640 medium and the apoptosis rates of the cells of 4 lines were observed after treatment of tumor necrosis factors related apoptosis indudng ligand (TRAIL) with a flow cytometer. The expression of NF-κB, survivin, Bcl-2 and Caspase3 in gastric cancer cells of 4 lines was analyzed with Western blot. RESULTS: After the gastric cancer cells were exposed to TRAIL 300 ng/ml for 24 hours, the apoptosis rate was 36.05%, 20.27%, 16.50% and 11.80% in MKN28, MKN45,AGS and SC-C-7901cells respectively. Western blot revealed that the expressions of NF-EB and survivin were lower in MKN28 cells than in MKN45, AGS and SGC-7901 cells. In contrast, the expression of Caspase3 was higher in MKN28 cells than in MKN45, AGS and SGC-7901 cells. CONCLUSION: There is a selectivity of TRAIL potency to induce apoptosis in gastric cancer cells of different cell lines.The anticancer potency of TRAIL is associated with the decreased expression of NF-κB and survivin and increased expression of Caspase3 of gastric cancer cells.     

Effect of NF-κB, survivin, Bcl-2 and Caspase3 on apoptosis of gastric cancer cells induced by tumor necrosis factor related apoptosis inducing ligand

AIM: To study the effect of NF-κB, survivin, Bcl-2 and Caspase3 on tumor necrosis factors related apoptosis inducing ligand (TRAIL) induced apoptosis of gastric cancer cells.METHODS: Gastric cancer cells of SGC-7901, MKN28,MKN45 and AGS lines were cultured in PRMI-1640 medium and the apoptosis rates of the cells of 4 lines were observed after treatment of tumor necrosis factors related apoptosis inducing ligand (TRAIL) with a flow cytometer. The expression of NF-κB, survivin, Bcl-2 and Caspase3 in gastric cancer cells of 4 lines was analyzed with Western blot.RESULTS: After the gastric cancer cells were exposed to TRAIL 300 ng/ml for 24 hours, the apoptosis rate was 36.05%, 20.27%, 16.50% and 11.80% in MKN28, MKN45,AGS and SGC-7901cells respectively. Western blot revealed that the expressions of NF-κB and survivin were lower in MKN28 cells than in MKN45, AGS and SGC-7901 cells. In contrast, the expression of Caspase3 was higher in MKN28 cells than in MKN45, AGS and SGC-7901 cells.CONCLUSION: There is a selectivity of TRAIL potency to induce apoptosis in gastric cancer cells of different cell lines.The anticancer potency of TRAIL is associated with the decreased expression of NF-κB and survivin and increased expression of Caspase3 of gastric cancer cells.     

HCTB006联合5-FU对胃癌细胞系MKN28、7901的作用及其机制

目的:探讨肿瘤坏死因子相关诱导配体受体(DR5)的单克隆抗体HCTB006联合5-FU对人胃癌细胞系7901、MKN28的作用以及机制.方法:用ATPlite法检测HBCT006单药组、5-FU单药组及两药物合用对胃癌细胞存活率的影响,研究两者之间的关系;采用流式细胞技术检测胃癌细胞系7901以及MKN28表面DR5的表达水平;Westernblot检测上述3组用药后胃癌细胞内XIAP,caspase3的变化.结果:胃癌细胞系7901、MKN28对HCTB006不敏感;5-FU对二者的增殖抑制作用具有时间以及浓度依赖效应;联合用药组具有很好的协同抑制胃癌细胞系增殖的效果,且具有浓度依赖效应,与给药次序无关.流式细胞技术检测胃癌细胞系7901,MKN28表面死亡受体DR5的表达依次为:93.8%以及87.7%.免疫迹印结果表明,联合用药组可以引发胃癌细胞内凋亡抑制蛋白XIAP的降解,激活最终凋亡执行蛋白caspase3,引起细胞死亡.结论:HTB006与5-FU联合应用具有协同杀伤胃癌细胞的作用.胃癌细胞7901、MKN28对于HCTB006的敏感程度与细胞表面DR5的表达量不相关;联合用药作用机制可能与细胞内抑制凋亡蛋白XIAP降解有关.     

Investigation of the sensitivities of distinct gastric cancer cells to parvovirus H‐1 induced cytotoxicity

OBJECTIVE: To investigate the sensitivities of distinct gastric cancer cells to parvovirus H‐1 induced cytotoxicity and the possible mechanism(s). METHODS: There were six distinct differentiated gastric cancer cell lines: HGC27 (undifferentiated), BGC823 (undifferentiated), MKN45 (poorly differentiated), AGS (poorly differentiated), SGC7901 (moderately differentiated) and MKN28 (well differentiated). The cell cycle distributions were measured by flow cytometry and the differential sensitivities of the six distinct gastric cancer cells after H‐1 virus infection were detected by MTT assay. RT‐PCR was used to detect viral NS1 gene expression in all six gastric cancer cell lines. RESULTS: The S phase ratios of HGC27, BGC823, MKN45, AGS, SGC7901 and MKN28 were 24.72%, 30.15%, 27.10%, 29.03%, 31.82% and 33.73%, respectively. HGC27 cells were sensitive to H‐1 virus induced cytotoxicity, followed by SGC7901 cells. MKN45 and AGS cells were moderately sensitive and MKN28 cells were insensitive. However, BGC823 cells were resistant to H‐1 virus induced cytotoxicity. The expressions of viral NS1 were higher in HGC27, BGC823, MKN45 and SGC7901 cells, and lower in AGS and MKN28 cells. CONCLUSIONS: The sensitivities of the distinct gastric cancer cells to H‐1 virus induced cytotoxicity were markedly different. In general, the poorly differentiated cells showed an enhanced sensitivity to H‐1 virus attack compared with well‐differentiated ones. The enhanced sensitivity of poorly versus well‐differentiated gastric cancer cells to H‐1 virus is related in part to the enhanced capacity of the former for NS1 protein production and accumulation. The undifferentiated BGC823 cells were resistant to H‐1 virus triggered cytotoxicity. It may further verify that not all tumor cells are sensitive to H‐1 virus lytic effects.     

正常上皮细胞特异性基因甲基化在胃癌发病机制中的研究

目的探讨正常上皮细胞特异性-1基因（NES1）在胃正常卜皮细胞和胃癌细胞株中的表达及其受甲基化调控的影响。方法分别培养胃癌细胞株MKN-28（高分化）、SGC-7901（中分化）、AGS（中分化）、MKN-45（低分化）、HGC-27（未分化）和原代正常胃上皮细胞。提取细胞RNA，荧光定量PCR检测NES1在各细胞株中的表达。以不同浓度的DNA甲基化酶抑制剂5＇-杂氮-2＇-脱氧胞嘧啶（5-azadC）处理胃癌细胞株，荧光定量PCR检测处理后NES1 mRNA表达。同时提取细胞基因组DNA，甲基化修饰后甲基特异性PCR（MSP）分析其CpG岛甲基化状态。结果NES1 mRNA在肿瘤细胞株中的表达较胃正常上皮细胞明显降低。甲基化检测显示，NES1在胃癌细胞株中均存在不同程度的外显子3CpG岛甲基化。NES1表达降低的胃癌细胞株经5-aza-dC去甲基化药物处理后NES1表达均有所上调。结论NES1在一些胃癌细胞株中的低表达与该基因外显子3CpG岛甲基化有关。5-aza-dC可使NESI表达降低的胃癌细胞株重新表达NES1 mRNA，再次证明了NES1基因在胃癌细胞株中的低表达与甲基化有关。NES1基因外显子3甲基化可能是胃癌细胞中NES1表达缺失的分子机制。     

Gastric cancer cell lines induced by trichostatin A

AIM： To explore the effect of trichostatin A （TSA） on apoptosis and acetylated histone H3 levels in gastric cancer cell lines BGC-823 and SGC-7901. METHODS： The effect of TSA on growth inhibition and apoptosis was examined by MTT, fluorescence microscopy and PI single-labeled flow cytometry. The acetylated histone H3 level was detected by Western blot. RESULTS： TSA induced apoptosis in gastric cancer cell lines BGC-823 and SGC-7901 was in a dose and time-dependent manner. Apoptotic cells varied significantly between TSA treated groups （37.5 ng/mL 72 h for BGC-823 cell line and 75 ng/mL 72 h for SGC-7901 cell line） and control group （0.85 ± 0.14 vs 1.14 ± 0.07, P = 0.02; 0.94 ± 0.07 vs 1.15 ± 0.06, P = 0.02）. Morphologic changes of apoptosis, including nuclear chromatin condensation and fluorescence strength, were observed under fluorescence microscopy. TSA treatment in BGC-823 and SGC-7901 cell lines obviously induced cell apoptosis, which was demonstrated by the increased percentage of sub-G1 phase cells, the reduction of Gl-phase cells and the increase of apoptosis rates in flow cytometric analysis. The result of Western blot showed that the expression of acetylated histone H3 increased in BGC-823 and SGC-7901 TSA treatment groups as compared with the control group.CONCLUSION： TSA can induce cell apoptosis in BGC-823 and SGC-7901 cell lines. The expression of acetylated histone H3 might be correlated with apoptosis.     

Interaction between cyclooxygenase-2,Snail,and E-cadherin in gastric cancer cells

AIM:To investigate the mechanisms of how cyclooxygenase-2(COX-2)regulates E-cadherin in gastric cancer cells.METHODS:COX-2 expression in human gastric cancer cell lines SGC-7901,BGC-823,MGC-803 and AGS were measured at the mRNA and protein level.COX-2 rich cell line SGC-7901 was chosen for subsequent experiments.siRNA mediated gene knockdown was used to investigate the impact of COX-2 on nuclear factor-κB (NF-κB),Snail,and E-cadherin in gastric cancer cells.Gene expression was determined by Western blot and real-time polymerase chain reaction.To analyze whether NF-κB inhibition could interrupt the modulatory effect of COX-2 or prostaglandin E2(PGE2)on E-cadherin,gastric cancer cells were treated with celecoxib or PGE2,in the presence of NF-κB specific siRNA.RESULTS:Highest expression level of COX-2 was found in SGC-7901 cells,both at mRNA and protein levels.siRNA mediated down-regulation of COX-2 led to a reduced expression of NF-κB and Snail,but an increased expression of E-cadherin in SGC-7901 cells.siRNA mediated down-regulation of NF-κB also led to a reduced expression of E-cadherin and Snail in SGC-7901 cells.However,COX-2 expression did not alter after cells were treated with NF-κB specific siRNA in SGC-7901 cells.Treatment of SGC-7901 cells with celecoxib led to a reduced expression of Snail but an increased expression of E-cadherin.In contrast,treatment of SGC-7901 cells with PGE2 led to an increased Snail and a decreased E-cadherin.However,siRNAmediated knockdown of NF-κB partially abolished the effect of celecoxib and PGE2 on the regulation of E-cadherin and Snail in SGC-7901 cells.CONCLUSION:COX-2 likely functions upstream of NF-κB and regulates the expression of E-cadherin via NF-κB/Snail signaling pathway in gastric cancer cells.