小干扰RNA沉默bcl-2基因抑制胃癌细胞生长的研究

目的利用RNA干扰技术,研究靶向bcl-2的小干扰RNA(siRNA)在体内外对胃癌细胞生长的影响,探讨其对胃癌治疗的可行性。方法化学合成bcl-2基因的siRNA,脂质体法将bcl-2 siRNA转染胃癌SGC 7901细胞,采用实时定量PCR和Western印迹观察bcl-2 siRNA转染前后胃癌细胞bcl-2基因的表达变化,四甲基偶氮唑盐(MTT)实验、流式细胞检测技术和端粒重复序列扩增法(TRAP)分别检测胃癌细胞增殖、凋亡和端粒酶活性变化。并将转染bcl-2 siRNA的胃癌SGC 7901细胞接种于裸鼠皮下,观察其在裸鼠体内成瘤及生长情况。结果数据经方差分析,bcl-2 siRNA转染胃癌SGC 7901细胞后,明显抑制bcl-2基因表达,并与其浓度和作用时间相关,以100 nmol/L bcl-2 siRNA对bcl-2基因表达抑制效果最佳。以该浓度的bcl-2 siRNA转染胃癌SGC 7901细胞后,bcl-2 mRNA和蛋白表达抑制分别为79．9%和85．3%；经bcl-2 siRNA作用的SGC 7901细胞生长明显缓于对照组(P＜0．05),细胞凋亡率高于对照组(P＜0．05),端粒酶活性明显低于对照组(P＜0．05)。转染100 nmol/L bcl-2 siRNA的胃癌SGC 7901细胞接种裸鼠皮下后,肿瘤出现时间晚,体积小．生长受到明显抑制(P＜0．05)。结论靶向bcl-2的siRNA可明显下调靶基因bcl-2的表达,在体内外抑制胃癌SGC 7901细胞的生长,为探索胃癌基因治疗提供新的策略。     

fas基因与bcl-2反义RNA转导胃癌耐药细胞的药敏上调效应

目的比较fas基因和bcl-2基因在胃癌耐药细胞与非耐药细胞表达的差异,将fas基因和bcl-2反义核酸导入胃癌耐药细胞,并分析转导前后的细胞在mRNA与蛋白的表达水平,研究转导株与非转导株对化疗药物敏感性的区别.方法采用分子克隆技术将fas 基因和反义bcl-2片段分别插入真核表达载体pBK-CMV和pDOR-SV40的多克隆克隆位点之间,以脂质体介导法将两个重组表达载体分别转染受体细胞SGC7901/ VCR,G418筛选克隆细胞,Northern blot, Western blot检测耐药细胞与非耐药细胞以及转导细胞中fas基因和bcl-2基因mRNA及其蛋白的表达,MTT法药敏实验检测转导细胞与非转导细胞对VCR、顺铂、5-FU 的敏感性.结果真核表达载体pBK-fas cDNA和pDOR-bcl-2 cDNA转导胃癌耐药细胞后,分别从2×105细胞中筛选出大约80和120个抗性克隆,转导率各为0.4‰和0.6‰,随机各挑选2个克隆继续筛选与扩增培养,均获得了稳定的抗性细胞,我们将此命名为SGC7901 fas/ VCR cell和SGC7901 anti bcl-2/ VCR cell. 杂交结果表明,胃癌耐药细胞SGC7901/ VCR与非耐药细胞相比,bcl-2基因的表达明显较高,而fas基因表达极其微弱. 转导株SGC7901 fas/ VCR cell的fas mRNA及其蛋白水平的表达显著高于非转导株,SGC7901 anti bcl-2/ VCR cell中bcl-2蛋白的表达明显低于非转导株. 2株转导细胞对VCR、顺铂、5-FU的敏感性明显高于非转导株.结论胃癌耐药细胞与非耐药细胞相比,bcl-2基因处于高表达状态,而fas基因处于极其低弱的表达状态. 通过脂质体介导的基因转染,有效地阻断了bcl-2蛋白在SGC7901 anti bcl-2/ VCR cell的表达,明显增强了fas mRNA及其蛋白在SGC7901 fas/ VCR cell的表达. bcl-2反义核酸和fas基因转导胃癌耐药细胞后,对化疗药物的敏感性明显增加.     

羟基喜树碱诱导胃癌细胞凋亡的作用机制初步研究

目的：研究羟基喜树碱（HCPT）诱导胃癌细胞的凋亡作用及对凋亡相关基因p53,c-myc,bcl-2,bcl-xl和bcl-xs表达的影响,探讨其诱导胃癌细胞凋亡的作用机制。方法：应用TUNEL染色、流式仪、免疫组化和RT－PCR技术等研究HCPT对胃细胞SGC－7901和MKN－45的诱导凋亡作用和对凋亡相关有达的影响。结果：HCPT作用于细胞后,可看到较为典型的细胞凋亡的形态学变化;细胞核固缩,染色质凝集,呈新月型紧核膜周边,核碎裂,染色质片段化,凋亡小体形成等。流式细胞仪DNA直方图上出现典型的亚二倍体的“凋亡峰”。流式细胞仪计数显示,10μg/ml的HCPT诱导胃癌细胞SGC－7901和MKN－45的凋亡率为21．88％和12．34％。TUNEL染色法显示,细胞凋亡指数在1．865－9．54％之间。免疫组化和RT－PCR结果显示：HCPT能够明显下调SGC－7901细胞的P53和bcl-2基因的蛋白和mRNA表达,对SGC－7901细胞的c-myc,bcl-xl和bcl-xs基因的蛋白表达无影响。HCPT作用后MKN－45细胞的p53蛋白和mRNA的表达增加,对MKN－45细胞的bcl-2,c-myc,bcl-xl和bcl-xs基因的表达无影响。结论：HCPT能够诱导胃癌细胞凋亡,可能是通过调控胃癌细胞的P53和bcl-2的表达而诱导胃癌细胞凋亡。     

p15INK4B和p21WAF1基因联合转染对人食管鳞癌细胞系EC109的协同抑制作用

目的:探讨p15INK4B和p21WAF1基因联合转染对人食管鳞癌细胞系EC109细胞增殖和凋亡的影响.方法:脂质体介导PcDNA3.1(+)-p15和pcDNA3.1(+)-p21转染EC109细胞,稳定筛选后用RT-PCR检测转染细胞p15与p21基因mRNA表达,Western blot检测转染细胞P15和P21蛋白的表达.用MTT法和透射电镜检测p15和p21基因分别及联合转染对EC109细胞增殖与凋亡的影响,流式细胞仪检测EC109细胞周期分布与凋亡率.结果:p15和p21转染组EC109细胞生长速度低于空载体组与未转染组,联合转染组与二者单独转染组相比.亦明显抑制EC109细胞体外生长速度.p15和p21转染组EC109细胞发生G1/S阻滞,G1期细胞比例显著高于空载体组和未转染组,S期则显著降低(G1期:60.52%±3.75%,63.12%±2.89% vs 42.17%±5.30%.41.38%±6.54%;S期:22.67%±1.25%,17.96%±2.03% vs 30.96%±3.33%,36.05%±1.78%,均P<0.01),并出现凋亡峰,透射电镜亦发现p15和p21转染组发生细胞凋亡,联合转染组发生更为明显的G1/S阻滞,G1期比例显著升高、S期比例明显降低(G1期:72.83%±2.31% vs60.52%±3.75%,63.12%±2.89%:S期:13.59%±2.59% vs 22.67%±1.25%,17.96%±2.03%.均P<0.05),凋亡率明显升高(21.21%±1.78%vs 4.32±1.74%,10.83%±2.40%,均P<0.01).结论:p15和p21基因联合转染在体外可以进一步增强对人食管鳞癌EC109细胞的抑制与诱导凋亡作用.     

p21WAF1基因对人食管鳞癌细胞增殖的抑制作用

目的:探讨p21WAF1( p21)基因转染对食管鳞癌细胞系EC109细胞增殖的影响.方法:根据转染质粒的不同和是否进行质粒转染分为3组.p21转染组:用脂质体Lipofectamine2000介导将pCDNA3.1(+)- p21质粒转染入EC109细胞; 空载体转染组:同样方法将pCDNA3.1(+)-neo质粒转染入EC109细胞; 未转染组:未转染的EC109细胞.应用RTPCR、Western blot分别检测p21基因mRNA、P21蛋白变化; 流式细胞仪分析细胞周期变化,应用MTT、流式细胞仪和透射电镜检测转染外源p21基因对EC109细胞增殖和凋亡的影响.结果:p21转染细胞中p21 mRNA和P21蛋白高表达; p21转染组EC109细胞生长速度低于空载体组和未转染组; 流式细胞仪观察到P21蛋白高表达使EC109细胞发生G1/S阻滞,G1期细胞比例显著高于空载体组和未转染组(63.120%±2.893% vs 41.380%±6.536%,42.173%±5.301%,均P<0.01),S期比例显著低于空载体组和未转染组(18.923%±3.084%vs 22.573%±5.463%,26.867%±2.922%,均P<0.01),并出现亚G1峰(凋亡峰).透射电镜亦发现p21转染组发生细胞凋亡.结论:p21基因转染可以抑制人食管鳞癌细胞系EC109细胞增殖并能诱导其发生细胞凋亡.     

莱菔硫烷诱导人胃癌SGC7901细胞凋亡的机制

目的研究莱菔硫烷(sulforaphane,SFN)在体外诱导人胃癌SGC7901细胞的凋亡作用,并探讨其作用机制。方法体外培养人胃癌SGC7901细胞,MTT比色法观察SFN对其增殖的影响。流式细胞术检测早期凋亡率、线粒体跨膜电位;免疫细胞化学法检测细胞Bax、Bcl-2、Bcl-X/L及Fas蛋白的表达;RT-PCR检测细胞Survivin基因mRNA表达。结果 SFN对SGC7901细胞的增殖具有明显抑制作用,SFN浓度在6.25～50μmmol/L之间时诱导SGC7901细胞凋亡的作用呈剂量依赖性(P0.01)。经SFN作用的SGC7901细胞线粒体跨膜电位降低,Bax及Fas蛋白表达水平上调,Bcl-X/L及Bcl-2/Bax表达水平降低;Survivin基因的mRNA表达降低(P0.01)。结论SFN可能通过下调Bcl-2/Bax及抑制Bcl-X/L蛋白的表达,活化Bax蛋白,诱导SGC7901进入内源性途径凋亡,外源性途径也可能起一定作用。SFN对SGC7901细胞的诱导凋亡作用还可能与抑制Survivin基因表达有关。     

Fas基因修饰胃癌耐药细胞的表达

目的将 Fas 基因导入胃癌耐药细胞,建立 Fas 基因表达耐药株,并比较转导前后 mRNA 与蛋白的表达水平。方法:采用分子克隆技术将 Fas 基因插入真核表达载体 pBK-CMV 的多克隆克隆位点之间,以脂质体介导法将重组表达载体转染受体细胞 SGC7901/VCR,G418筛选克隆细胞,Southern blot、Northern blot、Weston blot 检测Fas 基因和 Bcl-2基因的表达。结果:成功地构建了真核表达载体 pBK-Fas cDNA;转导细胞后,从2×10~5细胞中筛选出大约120个抗性克隆,转导率大于0.5‰,随机挑选2个克隆继续筛选与扩增培养,获得了1株稳定的抗生细胞,从而建立了 Fas 基因表达耐药株,我们命名为 SGC7901/VCR Fas cells;杂交结果表明,转导株与非转导株均有Fas cDNA 的表达,但转导株 Fas mRNA 及其蛋白水平的表达则显著高于非转导株。结论:在胃癌耐药细胞中 Fas基因处于低表达状态;通过脂质体介导的基因转染,Fas 基因可成功地导入胃癌耐药细胞,并能有效地增强 FasmRNA 及其蛋白的表达,为诱导细胞凋亡逆转胃癌耐药细胞的研究奠定了重要基础。     

HOXD10基因转染对人胃癌耐药SGC7901/VCR细胞增殖、凋亡及侵袭能力的影响

目的研究HOXD10基因转染人胃癌耐药细胞系SGC7901/VCR后表达情况及对细胞增殖、凋亡、侵袭能力的影响。方法将HOXD10基因表达质粒(pc DNA3.1-EGFP-HOXD10)转染至SGC7901/VCR中,利用Real-time PCR和Western blotting检测HOXD10基因转染后表达效果;MTT方法、平板单克隆实验、流式细胞术、Transwell方法分别检测HOXD10基因转染对细胞增殖、单克隆形成、细胞周期、凋亡、侵袭能力的影响;并用Western blotting检测HOXD10基因转染对肿瘤侵袭性相关因子MMP-2蛋白表达的影响。结果 HOXD10基因转染至人胃癌SGC7901/VCR细胞后其基因和蛋白表达水平均显著上升(P0.05),能够抑制SGC7901/VCR细胞增殖、单克隆形成、细胞周期,并提高顺铂作用下细胞凋亡率(P0.05),同时显著抑制细胞侵袭能力和MMP-2蛋白的表达(P0.05)。结论 HOXD10基因转染人胃癌耐药细胞系SGC7901/VCR后能够高表达,进而抑制细胞增殖、单克隆形成、细胞周期和侵袭能力并提高顺铂下细胞凋亡率,而其抑制细胞侵袭能力可能与MMP-2表达减少有关。     

p15INK4B基因转染联合亚砷酸对人食管鳞癌的协同抑制作用

目的探讨p15^INK4B（p15）基因转染与亚砷酸（As2O3）联合应用对人食管鳞癌细胞系EC109细胞增殖和凋亡的影响。方法脂质体介导将pcDNA3．1（＋）-p15转染EC109细胞，稳定筛选后加入2μmol／LAs2O3。PCR检测外源p15基因cDNA，Western印迹法检测转染细胞P15蛋白的表达。用MTT、集落形成实验和透射电镜检测p15基因转染联合As2O3对EC109细胞增殖和凋亡的影响，流式细胞仪检测EC109细胞周期分布和凋亡率。结果与二者单独应用相比，联合应用可明显抑制EC109细胞体外生长速度，集落形成率明显降低（P〈0．01），联合作用3d后发生更为明显的G1／S阻滞，G1期比例显著升高（P〈0．05），S期比例明显降低（P〈0．05），凋亡率明显升高（P〈0．01）。透射电镜发现二者联合应用诱导EC109发生更明显的细胞凋亡。结论p15基因转染与As2O3联合应用可以进一步增强对人食管鳞癌EC109细胞的抑制作用和诱导凋亡作用。     

转染Zbtb7a基因对人胃癌SGC7901细胞增殖、凋亡的影响及其机制

目的 观察转染Zbtb7a基因对人胃癌细胞系SGC7901增殖及凋亡的影响,并探讨其机制.方法 将pcDNA3.1-Zbtb7a和pSilencer 3.1-H1-mk用Lipofectamine2000转染SGC7901细胞,采用RT-PCR和Western Blot法检测MK mRNA及蛋白表达,CCK-8试剂盒和平板克隆法检测细胞增殖,流式细胞仪Annexin V-PI染色检测细胞凋亡.结果 转染Zbtb7a后,SGC7901细胞中MK表达水平明显升高,细胞增殖能力明显增强（P＜0.05）,并且0.5ng/mL TRAIL诱导的细胞凋亡受到抑制（P＜0.05）.Zbtb7a高表达后干扰MK的表达,细胞增殖及克隆能力则明显降低（P＜0.05）,TRAIL诱导的细胞凋亡数也明显增加（P＜0.05）.结论 Zbtb7a可以通过上调MK的表达,促进SGC-7901细胞增殖以及抑制TRAI诱导的细胞凋亡.     

Molecular therapy with recombinant antisense c-myc adenovirus for human gastric carcinoma cells in vitro and in vivo

BACKGROUND AND AIMS: This study used a recombinant antisense c-myc adenovirus (Ad-ASc-myc) to evaluate how alterations of c-myc expression in the SGC7901 human gastric carcinoma cells could influence the proliferation, apoptosis and the growth of human gastric tumors in nude mice. METHODS: The human gastric carcinoma cell line, SGC7901, treated with Ad-ASc-myc or adenovirus recombinants carrying LacZ gene (Ad-LacZ) were analyzed by using X-gal stain, MTT, DNA ladder, TUNEL assay, flow cytometric analysis, polymerase chain reaction and western blot in vitro. The tumorigenicity and experimental therapy in nude mice models were assessed in vivo. RESULTS: The Ad-ASc-myc could strongly inhibit cell growth and induce apoptosis in SGC7901 cells. The proliferation of the Ad-ASc-myc-infected SGC7901 cells was reduced by 44.1%. The mechanism of killing gastric carcinoma cells by Ad-ASc-myc was found to be apoptosis, which was detected by the use of a DNA ladder, TUNEL and flow cytometric analysis. Infection of Ad-ASc-myc in nude mice showed that all three mice failed to form tumors from the 7 to 30 day period, compared with injection of Ad-LacZ and parent SGC7901 cells. Experimental therapy on the nude mice bearing subcutaneous tumors of SGC7901 cells showed that intratumor instillation of Ad-ASc-myc inhibited the growth of the tumors. Recombinant antisense c-myc adenovirus-treated tumors were inhibited by 68.9%, compared with tumors injected with Ad-LacZ and control (LacZ and phosphate-buffered saline). CONCLUSION: The expression of Ad-ASc-myc can inhibit growth and induce apoptosis of gastric cancer cells in vitro and in vivo and thus is a potential clinical utility in gene therapy for the treatment of gastric carcinoma.     

The therapeutic effects of recombinant adenovirus RA538 on human gastric carcinoma cells in vitro and in vivo

AIM:To evaluate the potential of RA-538 gene therapy for gastric carcinoma.METHODS:Human gastric carcinoma cell line SGC7901 treated with Ad-RA538 or Ad-LacZ were analysed by X-gal stain, MTT, DNA ladder, Tunel, flow cytometric analysis, PCR, and Western Blot in vitro. The tumorigenicity and experimental therapy in nude mice model were assessed in vivo.RESULTS:Ad-LacZ could efficiently transfer the LacZ gene into SGC7901 cells. X-gal-positive cells at MOI 25, 50, 100, and 200 were 90%, 100%, 100%, and 100% respectively. Ad-RA538 could strongly inhibit cell growth and induced apoptosis in SGC7901 cells.The proliferation of the Ad-RA538-infected SGC7901 cells was reduced by 76.3%.The mechanism of killing of gastric carcinoma cells by Ad-RA538 was found to be apoptosis by DNA ladder,Tunel and flow cytometric analysis.The tumorigenicity in nude mice using Ad-RA538 showed that all three mice failed to form tumor from 7 to 30 days compared with Ad-LacZ and parent SGC7901 cells. Experimental therapy on the nude mice model bearing subcutaneous tumor of SGC7901 cells showed that intratumor instillation of Ad-RA538 inhibited the growth of the tumors. Ad-RA538-treated tumors were inhibited by 60.66%, compared with that of the tumor injected with Ad-LacZ and mock.CONCLUSION: The expression of Ad RA538 can inhibit growth and induce apoptosis of gastric cancer cell in vitro and in vivo. Ad RA538 can be used potentially in gene therapy for gastric carcinoma.     

重组反义c-myc 腺病毒对人胃癌细胞的体内及体外分子治疗

目的研究重组反义ｃｍｙｃ腺病毒对胃癌细胞的体内外生物学作用．方法采用ＬａｃＺ基因Ｘｇａｌ染色、ＭＴＴ,ＤＮＡ梯度降解试验、原位末端标记、流式细胞仪、ＰＣＲ分析、裸鼠致瘤性、裸鼠皮下移植瘤模型实验等方法,对反义ｃｍｙｃ重组腺病毒在人胃癌ＳＧＣ７９０１细胞系中的作用进行体内外研究．结果ＡｄＡＳｃｍｙｃ对ＳＧＣ７９０１细胞能产生明显的生长抑制作用,ＭＴＴ显示生长抑制率为４４１％．ＤＮＡ梯度降解试验、原位末端标记、流式细胞仪显示ＡｄＡＳｃｍｙｃ诱导了ＳＧＣ７９０１细胞凋亡．经ＡｄＡＳｃｍｙｃ处理的ＳＧＣ７９０１细胞裸鼠致瘤性消失．ＡｄＡＳｃｍｙｃ对裸鼠皮下移植瘤模型瘤内注射能有效降低肿瘤的生长速度,生长抑制率为６８９％．结论ＡｄＡＳｃｍｙｃ对胃癌细胞具有显著的体内外生长抑制及凋亡诱导作用     

抗Fas单克隆抗体诱导人胃癌细胞系SGC-7901细胞

目的探讨抗Ｆａｓ单克隆抗体诱导胃癌细胞凋亡的规律及在胃癌治疗中的意义．方法应用细胞形态观察、琼脂糖凝胶电泳、流式细胞光度术检测抗Ｆａｓ单克隆抗体对胃癌细胞ＳＧＣ７９０１增殖周期的影响以及对细胞杀伤作用的方式,并检测了ＳＧＣ７９０１细胞表面Ｂｃｌ２的表达情况．．结果抗Ｆａｓ单克隆抗体有阻滞细胞周期、通过诱发凋亡而抑制肿瘤细胞生长的作用．经抗Ｆａｓ单克隆抗体处理后,ＳＧＣ７９０１细胞表面Ｂｃｌ２蛋白表达无明显变化．．结论抗Ｆａｓ单克隆抗体可以诱导胃癌细胞系ＳＧＣ７９０１细胞凋亡．抗Ｆａｓ单克隆抗体诱导胃癌细胞凋亡与Ｂｃｌ２表达无关     

Suppression of P-gp induced multiple drug resistance in a drug resistant gastric cancer cell line by overexpression of Fas

AIM:To observe the drug sensitizing effect and related mechanisms of fas gene transduction on human drug-resistant gastric cancer cell SGC7901/VCR (resistant to Vincristine).METHODS:The cell cycle alteration was observed by FACS. The sensitivity of gastric cancer cells to apoptosis was determined by in vitro apoptosis assay. The drug sensitization of cells to several anti-tumor drugs was observed by MTT assay. Immunochemical method was used to show expression of P-gp and Topo II in gastric cancer cells.RESULTS:Comparing to SGC7901 and pBK-SGC7901/VCR, fas-SGC7901/VCR showed decreasing G2 cells and increasing S cells, the G2 phase fraction of pBK-SGC7901/VCR was about 3.0 times that of fas -SGC7901/VCR but S phase fraction of fas -SGC7901/VCR was about 1.9 times that of pBK-SGC7901/VCR, indicating S phase arrest of fas-SGC7901/VCR. FACS also suggested apoptosis of fas-SGC7901/VCR.fas-SGC7901/VCR was more sensitive to apoptosis inducing agent VM-26 than pBK-SGC7901/VCR. MTT assay showed increased sensitization of fas-SGC7901/VCR to DDP, MMC and 5-FU, but same sensitization to VCR according to pBK-SGC7901/VCR. SGC7901, PBK-SGC7901/VCR and fas -SGC7901/VCR had positively stained Topo II equally. P-gp staining in pBK-SGC7901/VCR was stronger than in SGC7901, but there was little staining of P-gp in fas-SGC7901/VCR.CONCLUSION:fas gene transduction could reverse the MDR of human drug-resistant gastric cancer cell SGC7901/VCR to a degree, possibly because of higher sensitization to apoptosis and decreased expression of P-gp.     

Therapeutic mechanism of ginkgo biloba exocarp polysaccharides on gastric cancer

AIM: To study the therapeutic mechanism of Ginkgo biloba exocarp polysaccharides (GBEP) on gastric cancer. METHODS: Thirty patients with gastric cancer were treated with oral GBEP capsules. The area of tumors was measured by electron gastroscope before and after treatment, then the inhibitory and effective rates were calculated. The ultrastructures of tumor cells were examined by transmissional electron microscope. Cell culture, MTT, flow cytometry were performed to observe proliferation, apoptosis and changes of relevant gene expression of human gastric cancer SGC-7901 cells. RESULTS: Compared with the statement before treatment, GBEP capsules could reduce the area of tumors, and the effective rate was 73.4%. Ultrastructural changes of the cells indicated that GBEP could induce apoptosis and differentiation in tumor cells of patients with gastric cancer. GBEP could inhibit the growth of human gastric cancer SGC-7901 cells following 24-72 h treatment in vitro at 10-320 mg/L, which was dose- and time-dependent. GBEP was able to elevate the apoptosis rate and expression of c-fos gene, but reduce the expression of c-myc and bcl-2 genes also in a dose-dependent manner. CONCLUSION: The therapeutic mechanism of GBEP on human gastric cancer may relate to its effects on the expression of c-myc, bcl-2 and c-fos genes, which can inhibit proliferation and induce apoptosis and differentiation of tumor cells.     

RNAi‐mediated silencing of ezrin gene reverses malignant behavior of human gastric cancer cell line SGC‐7901

OBJECTIVE: To investigate the effects of ezrin targeting gene of RNA interference (RNAi) on human gastric cancer cell line SGC‐7901 in vitro. METHODS: The highly metastatic human gastric cancer cell line SGC‐7901 transfected with a small interfering (siRNA) lentivirus vector was selected for this research study. Expressions of ezrin mRNA and ezrin protein in the SGC‐7901 cells were detected using RT‐PCR and Western blot. Cell apoptosis was observed using flow cytometry. Transwell invasion and the cell adhesion test were used to verify the effect of RNAi on ezrin expression in the human gastric cancer cell line SGC‐7901 in vitro. RESULTS: Ezrin gene targeting via a RNAi‐mediated lentivirus vector had obvious inhibitory effects on ezrin expression in the human gastric cancer cell line SGC‐7901. The results of the RT‐PCR show the obvious inhibition of ezrin mRNA expression in Eai and Ebi groups (0.22 ± 0.01 vs 0.95 ± 0.04, P < 0.05; 0.31 ± 0.01 vs. 0.95 ± 0.04, P < 0.05). Western blot analysis revealed a 72.35 ± 3.74% reduction of the ezrin protein level after interference with the ezrin targeting gene. Moreover, the inhibition of ezrin expression clearly inhibited SGC‐7901 cell migration and invasion, and improved cell adhesion as well as increased sensitivity to camptothecin‐induced apoptosis. CONCLUSION: Ezrin gene targeting by RNAi can inhibit the metastatic growth and migration of SGC‐7901 human gastric cancer cells.     

小干扰RNA抑制胃癌细胞环氧合酶-2的表达

目的 观察瞬时转染环氧合酶-2特异性小干扰RNA(COX-2 siRNA)对胃癌细胞增殖与凋亡的影响,探讨COX-2在胃癌发生中的作用和RNA干扰方法 对肿瘤的治疗作用.方法 以胃癌细胞系SGC7901为研究对象,瞬时转染COX-2 siRNA,转染后72 h用RT-PCR方法 分别检测COX-2siRNA组、无意义siRNA组及空白对照组的COX-2 mRNA表达;免疫组化法与Western blot检测3组细胞的COX-2蛋白质的表达;流式细胞仪检测3组的细胞周期和凋亡情况.转染后1周内每天同一时间用噻唑蓝比色分析法(MTr)检测3组癌细胞的活力并计算癌细胞的相对生存率.结果 COX-2siRNA对胃癌细胞中COX-2 mRNA及蛋白表达均有明显抑制作用,胃癌细胞增殖受到抑制,凋亡增加,但细胞周期分布无明显变化.结论 在胃癌细胞中,COX-2表达的抑制可降低胃癌细胞的增殖速度,促进肿瘤细胞凋亡,COX-2在胃癌的发生中可能具有重要作用.     

Effects of small interfering RNA inhibit Class Ⅰ phosphoinositide 3-kinase on human gastric cancer cells

AIM:To investigate the effects of small interfering RNA(siRNA)-mediated inhibition of Class Ⅰ phosphoinositide 3-kinase(Class Ⅰ PI3K) signal transduction on the proliferation,apoptosis,and autophagy of gastric cancer SGC7901 and MGC803 cells.METHODS:We constructed the recombinant replication adenovirus PI3K(I)-RNA interference(RNAi)-green fluorescent protein(GFP) and control adenovirus NCRNAi-GFP,and infected it into human gastric cancer cells.MTT assay was used to determine the growth rate of the gastric cancer cells.Activation of autophagy was monitored with monodansylcadaverine(MDC) staining after adenovirus PI3K(I)-RNAi-GFP and control adenovirus NC-RNAi-GFP treatment.Immunofluorescence staining was used to detect the expression of microtubule-associated protein 1 light chain 3(LC3).Mitochondrial membrane potential was measured using the fluorescent probe JC-1.The expression of autophagy was monitored with MDC,LC3 staining,and transmission electron microscopy.Western blotting was used to detect p53,Beclin-1,Bcl-2,and LC3 protein expression in the culture supernatant.RESULTS:The viability of gastric cancer cells was inhibited after siRNA targeting to the Class Ⅰ PI3K blocked Class Ⅰ PI3K signal pathway.MTT assays revealed that,after SGC7901 cancer cells were treated with adenovirus PI3K(I)-RNAi-GFP,the rate of inhibition reached 27.48% ± 2.71% at 24 h,41.92% ± 2.02% at 48 h,and 50.85% ± 0.91% at 72 h.After MGC803 cancer cells were treated with adenovirus PI3K(I)-RNAiGFP,the rate of inhibition reached 24.39% ± 0.93% at 24 h,47.00% ± 0.87% at 48 h,and 70.30% ± 0.86% at 72 h(P < 0.05 compared to control group).It was determined that when 50 MOI,the transfection efficiency was 95% ± 2.4%.Adenovirus PI3K(I)RNAi-GFP(50 MOI) induced mitochondrial dysfunction and activated cell apoptosis in SGC7901 cells,and the results described here prove that RNAi of Class Ⅰ PI3K induced apoptosis in SGC7901 cells.The results showed that adenovirus PI3K(I)-RNAi-GFP transfection induced punctate distribution of     

Transduction of Fas gene or Bcl-2 antisense RNA sensitizes cultured drug resistant gastric cancer cells to chemotherapeutic drugs

ＩＮＴＲＯＤＵＣＴＩＯＮＣｈｅｍｏｔｈｅｒａｐｙｉｓｏｎｅｏｆｔｈｅｍａｊｏｒｍｅｔｈｏｄｓｉｎｔｕｍｏｒｔｒｅａｔｍｅｎｔ,ｂｕｔｉｔｏｆｔｅｎｄｏｅｓｎｏｔｗｏｒｋｄｕｅｔｏｍｕｌｔｉｄｒｕｇｒｅｓｉｓｔａｎｃｅ（ＭＤＲ）．Ｒｅｃｅｎｔｓｔｕｄｉ...