胃癌细胞MKN28(p53-/-)对NSAIDs诱导凋亡敏感性的研究

目的1.明确非甾体消炎药(NSAIDs)能否诱导p53基因突变的胃癌细胞MKN28凋亡.2.明确NSAIDs对MKN28细胞凋亡相关基因bcl-2、bax表达的调控.方法1.通过MTT比色法检测NSAIDs对细胞生长活力的影响.2.应用丫啶橙染色、Annexin-Ⅴ/PI双染色、共聚焦显微镜、流式细胞术检测细胞凋亡.3.应用RT-PCR(逆转录-聚合酶链反应)方法检测bcl-2、bax基因水平的改变.结果1.NSAIDs药物吲哚美辛(Indo)和阿斯匹林(Asp)对胃癌细胞株MKN28均有生长抑制作用,且呈时间/浓度依赖性增强.2.在Indo 800μmol/L、Asp8 mmol/L作用48～96 h后,MKN28细胞凋亡数量稍有增多,但不具有统计学意义.3.随着药物作用时间的延长,MKN28细胞的bcl-2基因mRNA表达逐渐减弱,bax基因表达逐渐增强.结论1.NSAIDs可抑制MKN28胃癌细胞株增殖.2.NSAIDs不能诱导p53基因突变的MKN28胃癌细胞株发生显著的凋亡,提示p53基因突变可能阻断了NSAIDs诱导的细胞凋亡.3.NSAIDs可使MKN28细胞凋亡相关基因bcl-2和bax的水平呈现促进凋亡倾向的改变.     

Bax-Bcl-2异源二聚体与胃癌细胞凋亡的关系

目的：明确Bax-Bcl-2异源二聚体与NSAIDs诱导胃癌细胞凋亡的关系。方法：以NSAIDs诱导胃癌细胞凋亡,并通过丫啶橙(AO)染色、共聚焦显微镜、流式细胞术、TUNEL法加以证实。应用Western blot方法检测Bax、Bcl-2蛋白的表达,应用免疫沉淀-蛋白印迹法检测Bax-Bcl-2异源二聚体水平的改变。结果：NSAIDs药物吲哚美辛(indomethacin,indo)800 mmol/L和阿司匹林(aspirin,Asp)8 mmol/L作用24 h后,AGS细胞发生显著的凋亡(Indo 800 mmol/L作用24 h凋亡率(9．34±1．99)%,48 h(38．97±3．36)%,Asp 8 mmol/L 48 h凋亡率(17．60±3．30)%。随着药物作用时间的延长,Bax-Bcl-2异源二聚体水平逐渐增高,在6～48 h内均呈现增强趋势,Bax蛋白表达的增强在6～24 h最为明显,Bcl-2蛋白未检测到。结论：NSAIDs可诱导胃癌细胞AGS凋亡；Bax-Bcl-2异源二聚体可能具有促进细胞凋亡的作用,也可能是NSAIDs调控肿瘤细胞凋亡的一个重要作用点。     

土槿乙酸诱导人胃癌AGS细胞凋亡机制的研究

目的:研究土槿乙酸诱导人胃癌AGS细胞凋亡的作用机制.方法:采用Hoechst33342/PI核荧光双染色法, DNA片段化分析技术检测细胞凋亡的变化;FCM分析细胞周期的变化; Western 印迹法和RT-PCR法检测与细胞凋亡和细胞周期相关的蛋白及mRNA的表达.结果:土槿乙酸明显诱导人胃癌AGS细胞的凋亡,细胞周期被阻滞在G2/M期;10 μmol/L土槿乙酸作用AGS细胞12 h后p53表达增加,在36 h时达到峰值,24 h后可见p21WAF1/CIP1表达明显增加.土槿乙酸作用于AGS细胞后,增加了Fas/APO-1蛋白表达和促凋亡蛋白Bax mRNA的表达,降低了抑凋亡蛋白Bcl-2 mRNA表达,提高了caspase-3活性. 结论:土槿乙酸可通过p53激活Bcl-2介导的线粒体途径和Fas/APO-1介导的死亡受体途径诱导人胃癌AGS细胞凋亡.     

三氧化二砷诱导胃癌细胞凋亡及对相关基因表达的影响

目的 研究三氧化二砷（As2O3)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 癌凋亡的作用机制。方法 研究As2O3对胃癌细胞SGC－07901和MKN－45的诱导凋亡作用和对凋亡相关基因表达的影响。结果 As2O3作用于细胞可见典型的细胞凋亡。出现典型的亚二倍体“凋亡峰”。10μmol／LAs2O3的诱导胃癌细胞SGC－7901和MKN－45的凋亡率为13．8％和22．5％。细胞凋亡指数在1．42％－9．5％之间。As2O3作用后能明显下调SGC－7901细胞的bcl-2蛋白和mRNA的表达;对SGC－7901细胞的p53、c-myc、bcl-xl和bcl-xs蛋白的表达无影响。As2O3能促进MKN－45细胞的p53蛋白和mRNA的表达,对MKN－45细胞的bcl-2、c-myc、bcl-xl和bcl-xs基因表达无影响。结论 As2O3可通过不同途径诱导胃癌细胞凋亡,通过下调SGC－7901细胞的bcl-2的蛋白表达诱导其凋亡,通过上调p53表达诱导胃癌MKN－45细胞凋亡。     

Ad-PTEN体外对SGC-7901胃癌细胞生长的抑制作用

目的：探讨腺病毒介导的PTEN基因表达体外对SGC-7901胃癌细胞生长抑制作用及其分子机制。方法：将携有PTEN基因的复制缺陷型腺病毒载体（Ad-PTEN）感染SGC-7901胃癌细胞,用RT-PCR法检测Ad-PTEN在细胞中的表达,光学显微镜及荧光显微镜下观察Ad-PTEN感染细胞前后形态的变化,MTT法检测Ad-PTEN对SGC-7901胃癌细胞生长的抑制作用,用流式细胞术（FCM）检测SGC-7901胃癌细胞凋亡率。RT-PCR分析Bax、Bcl-2、p53、Survivin细胞凋亡相关基因的表达。结果：Ad-PTEN基因组感染SGC-7901胃癌细胞后,RT-PCR结果显示PTEN目的基因能在SGC-7901胃癌细胞中转录,其表达可明显抑制该胃癌细胞的生长,并诱导细胞凋亡。其凋亡机制可能与Bax/Bcl-2比值、p53基因表达上调、Survivin下调有关。结论：重组腺病毒Ad-PTEN具有抑制SGC-7901胃癌细胞生长和诱导细胞凋亡的作用。     

Ad-PTEN体外对SGC-7901胃癌细胞生长的抑制作用

目的:探讨腺病毒介导的PTEN基因表达体外对SGC-7901胃癌细胞生长抑制作用及其分子机制。方法:将携有PTEN基因的复制缺陷型腺病毒载体(Ad-PTEN)感染SGC-7901胃癌细胞,用RT-PCR法检测Ad-PTEN在细胞中的表达,光学显微镜及荧光显微镜下观察Ad-PTEN感染细胞前后形态的变化,MTT法检测Ad-PTEN对SGC-7901胃癌细胞生长的抑制作用,用流式细胞术(FCM)检测SGC-7901胃癌细胞凋亡率。RT-PCR分析Bax、Bcl-2、p53、Survivin细胞凋亡相关基因的表达。结果:Ad-PTEN基因组感染SGC-7901胃癌细胞后,RT-PCR结果显示PTEN目的基因能在SGC-7901胃癌细胞中转录,其表达可明显抑制该胃癌细胞的生长,并诱导细胞凋亡。其凋亡机制可能与Bax/Bcl-2比值、p53基因表达上调、Survivin下调有关。结论:重组腺病毒Ad-PTEN具有抑制SGC-7901胃癌细胞生长和诱导细胞凋亡的作用。     

纤维粘连蛋白与整合素结合调控肿瘤细胞的凋亡

目的：探讨细胞表面整合素受体蛋白与纤维粘连蛋白的结合在肿瘤细胞逃避凋亡中的作用及其信号传导途径。方法：用免疫荧光法检测人鳞状上皮细胞癌HSC-3细胞中整合素受体蛋白亚单位的表达；建立细胞悬浮分离培养导致凋亡的模型；利用封闭抗体法检测不同整合素受体蛋白亚单位在此凋亡过程中的作用；Western blot检测：P53及Bcl-2／Bax在凋亡过程中表达蛋白的变化。结果：整合素受体蛋白av在正常上皮细胞中表达少或无，但在HSC-3细胞中表达较强。av封闭抗体可明显提高HSC-3细胞凋亡程度。在纤维粘连蛋白作用的HSC一3细胞中，p53蛋白表达受抑制，凋亡调节蛋白Bcl-2表达上升，Bax表达下降，Bcl-2／Bax比率上升，细胞凋亡率降低。结论：HSC-3细胞表面整合素受体蛋白av通过与纤维粘连蛋白结合，抑制了P53蛋白的表达，提高了细胞凋亡调节蛋白Bcl-2／Bax的比率，这是HSC-3细胞避免凋亡的重要原因之一。     

大黄素对人胃癌细胞MKN45增殖抑制作用及其分子机制的探讨

目的:研究大黄素(Emodin)对人胃癌细胞MKN45的作用及探讨其诱导MKN45凋亡的分子机制。方法:用MTT法观察大黄素对MKN45的生长抑制作用;荧光染色法及流式细胞仪分析诱导凋亡作用;蛋白质印迹法检测p53和p21蛋白水平的变化;细胞免疫化学法检测Fas的表达。结果:与对照组相比,大黄素能明显抑制MKN45细胞的生长且呈浓度、时间依赖性,其IC50(48h)为(47.5±0.3)μmol/L;大黄素处理胃癌细胞后,吖啶橙(AO)染色观察示,细胞核内可见浓染致密的颗粒荧光、新月型改变、核固缩或片段化及凋亡小体的形成。流式细胞仪分析显示,大黄素能浓度依赖性诱导MKN45细胞凋亡和G2/M期阻滞。蛋白质印迹法检测显示,随着药物浓度的不断增加,p53和p21WAF1蛋白水平表现出明显增强的趋势;细胞免疫化学方法显示,大黄素处理后的细胞Fas/APO-1表达较对照组明显增多。结论:大黄素对人胃癌细胞MKN45有明显的生长抑制作用,且该作用与p53依赖性诱导凋亡以及Fas表达水平的上调有关。     

腺病毒介导p21WAF1/CIP1基因转移及诱导胃癌细胞凋亡

目的：探讨p21^WAF1/CIP1基因（p21基因）过表达对人胃癌细胞恶性表型和细胞凋亡的影响，进一步了解p21基因对肿瘤细胞的治疗作用。方法：通过腺病毒介导外源性p21基因转移到有p53基因突变的人胃癌细胞系SGC－7901，对p21基因的表达、细胞生长的抑制与投机和对肿瘤模型的治疗效果进行分析。结果：外源性p21基因在靶细胞高水平表达显著抑制了胃癌细胞的生长和集落形成，流式细胞仪检测显示G1期阻滞并发生了凋亡。瘤内注射Ad-p21对裸鼠体内移植瘤有一定抑瘤作用。结论；p21基因可能参与肿瘤细胞凋亡的诱导，使p21基因在肿瘤的基因治疗，特别是在与其他凋亡诱导因子联合作用的方案中有更好的应用前景。     

新型硫色满酮衍生物抑制胃癌细胞生长与诱导胃癌细胞凋亡机制研究

摘 要：［目的］ 研究(顺)-3(氯代亚甲基)-5,7-二氯-硫色满-4-酮［(Z)-3( chloromethyl- ene)-5,7(dichloro)- thiochroman-4- ketone,CMDCT］对体外低、中、高分化的人胃癌细胞株生长抑制作用与诱导胃癌细胞凋亡机制研究。［方法］ MTT法测试CMDCT对3种胃癌细胞株的生长抑制;以中分化胃癌细胞(SGC-7901)为例,流式细胞术(FCM)和缺口末端核苷酸标记法(TUNEL)检测胃癌SGC-7901细胞的凋亡;ELISA法测定胃癌SGC-7901细胞内被激活的人半胱氨酸蛋白酶3(Caspase-3)的量;PCR检测Bcl-2、Bax、p53、Caspase-3基因表达;Western blot检测胃癌SGC-7901细胞中Bcl-2、Bax、p53、Caspase-3蛋白表达情况。［结果］CMDCT对3种胃癌细胞的生长具有显著抑制作用,随CMDCT浓度升高细胞生长的抑制率越高,当药物浓度为40μmol/L时,抑制率在(66．53%±2．47%)～(76．12%±1．35%)之间,和同浓度顺铂（DDP）组相比有较大差异;TUNEL检测胃癌SGC-7901细胞的凋亡指数：对照组为1．61%±0．23%;低浓度组为12．55%±1．44%;高浓度组61.15%±1．77%,加药组细胞凋亡指数明显高于对照组;流式细胞术结果显示,对照组凋亡率为4．78%±0．41%;加药组加入浓度10μmol/L、20μmol/L、40μmol/L 药物后,凋亡率分别为(9．42%±1．27%),(21.07%±1．35%),(55．8%±10．03%),明显高于对照组细胞凋亡率;PCR和Western blot检测,与对照组对比,加药组的Bax、p53和Caspase-3基因和蛋白表达量均增高,均具有上调作用,Bcl-2基因和蛋白表达降低,呈下调趋势。 ［结论］ CMDCT对体外人低、中、高分化的3种胃癌细胞株均具有生长抑制作用,且可以诱导细胞凋亡,通过使具有促凋亡作用的p53、Bax、Caspase-3高表达,及抗细胞凋亡作用的Bcl-2的低表达,有效地诱导了胃癌SGC-7901细胞凋亡。     

Non-steroidal anti-inflammatory drugs induce apoptosis in gastric cancer cells through up-regulation of bax and bak

Aspirin- and non-steroidal anti-inflammatory drug (NSAID)-induced apoptosis is one of the important mechanisms for their anti-tumour effect in gastric cancer. We aimed at determining the role of bcl-2 family proteins and caspases in the apoptotic process. Gastric cancer cell lines AGS (wild-type p53) and MKN-28 (mutant p53) were used. Cell proliferation was measured by MTT assay. Apoptosis was determined by acridine orange staining. Protein expressions were determined by western blotting. Aspirin and indomethacin inhibited cell proliferation and induced apoptosis in both cells. AGS cells were more sensitive compared with MKN-28 cells. The pro-apoptotic proteins bax and bak were overexpressed after treatment, while the protein level of bcl-2 remained unchanged. Apoptosis was accompanied by an increase in caspase-3 activity and cleavage of caspase-3 and poly(ADP-ribose) polymerase. Inhibition of caspase-3 rescued aspirin-induced apoptosis. Our results suggest that one of the major pathways which mediates the anti-tumour response of aspirin and indomethacin in gastric cancer cells is through up-regulation of bax and bak and activation of caspase-3. Bax and bak are important in the chemoprevention of gastric cancer.     

Inhibition of proteasome function induced apoptosis in gastric cancer

The ubiquitin-proteasome pathway plays a critical role in the degradation of cellular proteins and cell cycle control. Dysregulating the degradation of such proteins should have profound effects on tumor growth and causes cells to undergo apoptosis. The aims of this study are to evaluate the ubiquitin-proteasome pathway in gastric cancer and the potential role of pharmacological inhibition of proteasome on induction of apoptosis in gastric cancer cells. Gastric cancer cell lines AGS (p53 wild-type) and MKN-28 (p53 mutant) were treated with proteasome inhibitor MG132. The results showed that MG132 inhibited cell proliferation in AGS and MKN-28 cells in a time- and dose-dependent manner. The inhibition of cell proliferation was caused by apoptosis which was also time- and dose-dependent. AGS cells were more responsive to MG132 than MKN-28 cells. Induction of apoptosis was preceded by the activation of caspase-3, as measured by a colorimetric caspase-3 cellular activity and Western blotting of the cleavage of caspase-3 and its substrate PARP. Activation of caspase-7 was also exhibited. In addition, z-VAD-fmk, a broad spectrum caspase inhibitor, reversed apoptosis induced by MG132 in AGS and MKN28 cells. Although z-DEVD-fmk, a specific caspase-3 inhibitor, suppressed MG132-induced apoptosis in MKN28 cells, it only partially rescued the apoptotic effect in AGS cells. Caspase-3 activation was the result of release of cytochrome c from mitochondria into the cytosol, as a consequence of upregulation of bax. There were overexpressions of all the proteasome-related proteins p53, p21(waf1) and p27(kip1) at 4 hr after proteasome inhibition which was identified by the accumulation of ubiquitin-tagged proteins. This was accompanied by accumulation of cells at G(1) phase. Our present study suggests that inhibition of proteasome function in gastric cancer cells induces apoptosis and proteasomal inhibitors have potential use as novel anticancer drugs in gastric cancer.     

Arsenic trioxide induces apoptosis in human gastric cancer cells through up-regulation of p53 and activation of caspase-3

Arsenic trioxide (As(2)O(3)) can induce clinical remission in patients suffering from acute promyelocytic leukemia, through induction of apoptosis and activation of caspases. We investigated the potential use of As(2)O(3) in human gastric cancer and its possible mechanisms. Human gastric cancer cell lines AGS and MKN-28 were treated with various concentrations (0.1 to 100 microM) of As(2)O(3) for 24 to 72 hr. Apoptosis was determined by acridine orange staining, flow cytometry and DNA fragmentation. Protein levels of p53, p21(waf1/cip1), c-myc, bcl-2 and bax were detected by Western blotting. Effects of As(2)O(3) on caspase-3 protease activity, its protein concentration and cleavage of poly(ADP)-ribose polymerase (PARP) were also studied. As(2)O(3) inhibited cell growth and induced apoptosis in both cell lines, though AGS cells were more sensitive. As(2)O(3) induced apoptosis in AGS cells in a concentration- and time-dependent manner. Treatment resulted in a marked increase in p53 protein levels as early as 4 hr. Co-incubation with p53 anti-sense oligo-nucleotide suppressed As(2)O(3)-induced intracellular p53 over-expression and apoptosis. As(2)O(3) increased the activity of caspase-3, with appearance of its 17 kDa peptide fragment, and cleavage of PARP, with appearance of the 85 kDa cleavage product, both in parallel with the induction of apoptosis. Both the tripeptide caspase inhibitor zVAD-fmk and the specific caspase-3 inhibitor DEVD-fmk partially suppressed As(2)O(3)-induced caspase-3 activation and apoptosis. As(2)O(3) inhibits cell growth and induces apoptosis in gastric cancer cells, involving p53 over-expression and activation of caspase-3. The potential use of this compound in the treatment of gastric cancer is worth further investigation.     

Apoptosis induced by 5-fluorouracil, cisplatin and paclitaxel are associated with p53 gene status in gastric cancer cell lines

In a recent study, we evaluated the efficacy and toxicity of 5-fluorouracil (5-FU), cisplatin (CDDP), and 5-FU plus CDDP (FP treatment) in gastric cancer cell lines and examined the relationship between the response to FP treatment and apoptosis. Our study indicated that there may be prognostic value in measuring p53 prior to FP treatment, and that cancers with wild-type p53 may be better candidates for FP treatment than those with mutant-type p53 in gastric cancer patients. In the present study, because cells with mutant-type p53 are suggested to be less responsive to FP chemotherapy treatment, we examined the relationship between the response to paclitaxel and apoptosis in MKN45 and MKN28 human gastric cancer cell lines by flow cytometry. In both MKN45 and MKN28 cells, paclitaxel arrested cells in the G2/M phases of the cell cycle after 24 h. Additionally, in both MKN45 and MKN28 cells, paclitaxel produced a significant rise in the number of subG1-phase cells after 72 h by the flow cytometry histogram. From these results, our previous study suggests that cells with mutant-type p53 may be less responsive to FP treatment and the present study indicates that another anti-cancer drug like paclitaxel, which might be mediated by a p53-independent pathway, should be selected. These insights may provide a new strategy for gastric cancer chemotherapy, especially second-line chemotherapy or adjuvant chemotherapy.     

12-Lipoxygenase inhibition induced apoptosis in human gastric cancer cells

Arachidonic acid release from membrane phospholipids is essential for tumour cell proliferation. Lipoxygenases constitute a pathway for arachidonate metabolism. The present study investigated the expression of 12-lipoxygenase and its effect on cell proliferation as well as survival in two human gastric cancer cell lines (AGS and MKN-28). RT-PCR and western blots, respectively, showed 12-LOX mRNA and protein expression in both AGS and MKN-28 cell lines. Treatment with a 12-LOX inhibitor, baicalein, significantly inhibited cancer cell proliferation, but a metabolite of 12-LOX activity, 12 hydroxyeicosatetraenoic acid (12-HETE) reversed baicalein-induced growth inhibition. Furthermore, the blockade of the 12-LOX pathway through a 12-LOX inhibitor and antisense induced apoptosis of gastric cancer cell lines. The biochemical characteristics of apoptosis were p53-independent combined with a decrease in bcl-2 expression. Caspase-7 was proteolytically activated and responsible for the apoptosis execution.     

红毛五加多糖对胃癌细胞的诱导凋亡作用

目的：研究红毛五加多糖对胃癌的诱导凋亡作用及其作用机制。方法：采用流式细胞术检测凋亡细胞百分比及基因和细胞因子蛋白含量。结果：该多糖使癌基因bcl-2蛋白表达降低,而使抑癌基因p53、bax、Fas、Fas-L及细胞因子TGFβ1蛋白表达增高。结论：该多糖通过降低原癌基因蛋白表达,增高抑癌基因和细胞因子蛋白表达,从而诱导胃癌细胞SGC-7901凋亡。     

Susceptibility for NSAIDs-induced apoptosis correlates to p53 gene status in gastric cancer cells

The anti-tumor effect of non-steroidal anti-inflammatory drugs (NSAIDs) remains unclear. Here, we found that the susceptibility for NSAIDs-induced apoptosis might correlate with the status of the p53 gene in gastric cancer cells. Apoptosis in gastric cancer cells expressing wild-type p53 is induced through up-regulation of bax and down-regulation of bcl-2 and that regulation of the bax-bcl-2 heterodimer may be a major target of NSAIDs. As to gastric cancer cells expressing mutant-type p53, other key factors may exist in the NSAIDs' growth inhibition action.     

Activation and the interaction of proapoptotic genes in modulating sensitivity to anticancer drugs in gastric cancer cells.

Taxotere (Docetaxel) is a novel microtubulin inhibitor which is currently in phase II/III clinical trial. We found that the sensitivity to taxotere was correlated with apoptotic cell death determined by the internucleosomal DNA ladders in gastric cancer cell lines. The treatment of taxotere activated proapoptotic genes such as bcl-Xs and bax genes. The relationship between the mRNA induction of bcl-Xs and bax genes and the internucleosomal DNA ladders by taxotere was significant, respectively (p<0.05). The introduction of bcl-Xs gene into MKN45 gastric cancer cells increased the sensitivity to VP-16 and taxotere 2-3-fold in the IC50 values, whereas the introduction of bax gene increased the sensitivity to CDDP, VP-16 and taxotere 2-5-fold in the IC50 values, as compared to that of the Neo-transfected MKN45 cells. The mRNA overexpression of bax gene was found in the bcl-Xs-transfected cells. Likewise, the mRNA overexpression of bcl-Xs gene was also found in the bax-transfected cells. These results indicate that the activation of bcl-2 family genes such as bcl-Xs and bax plays a crucial role in modulating apoptotic cell death in the sensitivity to anticancer drugs, and suggest that these proapoptotic genes might interact in the up-regulation for activating downstream signals leading to apoptosis in gastric cancer cells.     

全反式维甲酸对食管癌细胞系EC109作用的研究

目的 探讨不同浓度全反式维甲酸(ATRA)对食管癌细胞系EC109的生长抑制作用及其机理.方法 不同浓度ATRA作用于细胞EC109,采用MTT法检测细胞生长;通过流式细胞仪检测和DNA梯状电泳证实凋亡存在;用RT-PCR方法检测凋亡诱导过程中p53、bcl-2和bax基因表达变化.结果 ATRA呈剂量及时间依赖性抑制细胞生长;琼脂糖电泳呈现凋亡DNA梯状条带;流式细胞仪分析存在明显的凋亡峰;ATRA处理组bax和p53基因表达上调,但bcl-2基因表达下调.结论 ATRA具有抑制食管癌细胞株EC109生长作用,其机理可能是诱导细胞凋亡,其分子机制可能与bcl-2/bax和p53的表达相关.     

bcl-2硫代反义寡核苷酸提高胃癌细胞凋亡的敏感性

OBJECTIVE: To study the effect of bcl-2 anti-sense oligonucleotide on the sensitivity of gastric cancer cells to Fas-mediated apoptosis. METHODS: Gastric cancer cell line MKN45 was transfected with bcl-2 anti-sense oligonucleotide, and expression of bcl-2 was examined by Western blotting. Agonistic Fas antibody was used to induce apoptosis detected by TUNEL staining and flow cytometry. RESULTS: Bcl-2 expression in MKN45 cells transfected with bcl-2 anti-sense oligonucleotide was markedly inhibited. When cultured with antibody apoptosis index of the anti-sense oligonucleotide-treated MKN45 cells was 55.6% +/- 4.7% (n = 5), which was significantly higher than that of the control (8.4% +/- 2.1%, n = 5). CONCLUSION: Expression of bcl-2 in gastric cancer cells may antagonize Fas-mediated apoptosis.