Paclitaxel induces apoptosis in human gastric carcinoma cells

AIM: To investigate the apoptosis in gastric cancer cells induced by paclitaxel, and the relation between this apoptosis and expression of Bcl-2 and Bax. METHODS: In in vitro experiments, MTT assay was used to determine the cell growth inhibitory rate. Transmission electron microscope and TUNEL staining method were used to quantitatively and qualitively detect the apoptosis status of gastric cancer cell line SGC-7901 before and after the paclitaxel treatment. Immunohistochemical staining was used to detect the expression of apoptosis-regulated gene Bcl-2 and Bax. RESULTS: Paclitaxel inhibited the growth of gastric cancer cell line SGC-7901 in a dose-and time-dependent manner. Paclitaxel induced SGC-7901 cells to undergo apoptosis with typically apoptotic characteristics, including morphological changes of chromatin condensation, chromatin crescent formation, nucleus fragmentation and apoptotic body formation. Paclitaxel could reduce the expression of apoptosis-regulated gene Bcl-2, and improve the expression of apoptosis-regulated gene Bax. CONCLUSION: Paclitaxel is able to induce the apoptosis in gastric cancer. This apoptosis may be mediated by down-expression of apoptosis-regulated gene Bcl-2 and up-expression of apoptosis-regulated gene Bax.     

Induction of apoptosis of human gastric carcinoma SGC-7901 cell line by 5, 7-dihydroxy-8-nitrochrysin in vitro

AIM： To investigate the effect of 5, 7-dihydroxy-8- nitrochrysin （NOChR） on apoptosis of human gastric carcinoma SGC-7901 cell line.
METHODS： SGC-7901 cells were cultured in vitro and the inhibitory effect of NOChR on proliferation of SGC-7901 cells was measured by using an Ml-r assay. NOChR-induced apoptosis rate of SGC-7901 cells was detected using flow cytometry （FCM） with PI staining. DNA ladder bands were observed by DNA agarose gel electrophoresis. The influence of NOChR on the proxisome proliferator-activated receptor-γ （PPARγ）, Bcl-2 and Bax protein expression of SGC-7901 cells was analyzed by Western blot.
RESULTS： MIF assay showed that NOChR markedly inhibited proliferation of SGC-7901 cells in a dose- dependent manner, and when ICso was 4.14 μmol/L, the potency of NOChR was 10 times than that of lead compound, chrysin （ChR, IC50 was 40.56 μmol/L）, and was similar to 5-fluorouracil （5-FU, IC50 was 4.51 μmol/L）. FCM with propidium iodide （PI） staining demonstrated that the apoptosis rates of SGC-7901 cells treated with 1.25, 5.00 and 20.00 μmol/L NOChR for 48 h were 9.8% 4- 0.2%, 36.8% 4- 1.9% and 45.5% 4- 3.5%, respectively, and were significantly higher when treated with 5.00 and 20.00 μmol/L NOChR than that with 20.00 μmol/L ChR （12.9% 4- 1.5%）. DNA agarose gel electrophoresis showed that treatment of SGC-7901 cells with 20.00 μmol/L NOChR for 48 h resulted in typical DNA ladder bands of DNA of SGC-7901 cells, which could be eliminated by treating with 10.00 μmol/L GW9662, a blocker of PPARy. Western blot analysis revealed that after 24 h of treatment with 20.00 μmol/L NOChR, PPARgamma and Bax protein expression of SGC-7901 cells increased but Bcl-2 expression decreased; however, pre-incubation with 10.00 μmol/L GW9662 could efficiently antagonize and weaken the regulatory effect of 20.00 μmol/L NOChR on Bax and Bcl-2 protein expression of SGC-7901 cells.
CONCLUSION： NOChR induces apoptosis of SGO7901 cell lines by activating PPARy and decreasing ra     

Tributyrin inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM: To evaluate the effects of tributyrin, a pro-drug of natural butyrate and a neutral short-chain fatty acid triglyceride, on the growth inhibition of human gastric cancer SGC-7901 cell. METHODS: Human gastric cancer SGC-7901 cells were exposed to tributyrin at 0.5, 1, 2, 5, 10 and 50 mmol/L(-1) for 24-72 h. MTT assay was applied to detect the cell proliferation. [(3)H]-TdR uptake was measured to determine DNA synthesis. Apoptotic morphology was observed by electron microscopy and Hoechst-33258 staining. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect tributyrin-triggered apoptosis. The expressions of PARP, Bcl-2 and Bax were examined by Western blot assay. RESULTS: Tributyrin could initiate growth inhibition of SGC-7901 cell in a dose- and time-dependent manner. [(3)H]-TdR uptake by SGC-7901 cells was reduced to 33.6 % after 48 h treatment with 2 mmol/L(-1) tributyrin, compared with the control (P<0.05). Apoptotic morphology was detected by TUNEL assay. Flow cytometry revealed that tributyrin could induce apoptosis of SGC-7901 cells in dose-dependent manner. After 48 hours incubation with tributyrin at 2 mmol/L(-1), the level of Bcl-2 protein was lowered, and the level of Bax protein was increased in SGC-7901, accompanied by PARP cleavage. CONCLUSION: Tributyrin could inhibit the growth of gastric cancer cells effectively in vitro by inhibiting DNA synthesis and inducing apoptosis, which was associated with the down-regulated Bcl-2 expression and the up-regulated Bax expression. Therefore, tributyrin might be a promising chemopreventive and chemotherapeutic agent against human gastric carcinogenesis.     

Tributyrin inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM: To evaluate the effects of tributyrin, a pro-drug of natural butyrate and a neutral short-chain fatty acid triglyceride, on the growth inhibition of human gastric cancer SGC-7901 cell.METHODS: Human gastric cancer SGC-7901 cells were 24-72 h. MTT assay was applied to detect the cell proliferation.[3H]-TdR uptake was measured to determine DNA synthesis.Apoptotic morphology was observed by electron microscopy and Hoechst-33258 staining. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect tributyrin-triggered apoptosis. The expressions of PARP, Bcl-2 and Bax were examined by Western blot assay.RESULTS: Tributyrin could initiate growth inhibition of SGC7901 cell in a dose- and time-dependent manner. [3H]-TdR uptake by SGC-7901 cells was reduced to 33.6% after 48 h control (P＜0.05). Apoptotic morphology was detected by TUNEL assay. Flow cytometry revealed that tributyrin could induce apoptosis of SGC-7901 cells in dose-dependent manner. After 48 hours incubation with tributyrin at 2 mmol.L-1, the level of Bcl-2 protein was lowered, and the level of Bax protein was increased in SGC-7901, accompanied by PARP cleavage.CONCLUSION: Tributyrin could inhibit the growth of gastric cancer cells effectively in vitro by inhibiting DNA synthesis and inducing apoptosis, which was associated with the downregulated Bcl-2 expression and the up-regulated Bax expression. Therefore, tributyrin might be a promising chemopreventive and chemotherapeutic agent against human gastric carcinogenesis.     

2-(3羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖对人胃癌细胞系(SGC-7901)的诱导凋亡作用

目的 观察2-（3-羧基-1-丙酰氨基）-2-脱氧-D-葡萄糖（COADG）体外诱导人胃癌细胞SGC-7901凋亡的作用,探讨其可能的作用机理。方法 采用MTT法,筛选药物作用最佳浓度。用流式细胞仪、琼脂糖凝胶电泳分析诱导凋亡前后的细胞DNA含量,用透射电镜观察凋亡细胞的超微结构。结果 2-（3-羧基-1-丙酰氨基）-2-脱氧-D-葡萄糖能明显抑制胃癌细胞的增长,MTT法显示抑制程度具有时间和剂量效应关系,组间比较表达差异有显著性;流式细胞仪分析可见亚二倍体（Sub—G1）凋亡峰;电镜观察到凋亡小体。结论 2-（3-羧基-1-丙酰氨基）-2-脱氧-D-葡萄糖有诱导人胃癌细胞（SGC-7901）凋亡的作用。     

Effects of allicin on both telomerase activity and apoptosis in gastric cancer SGC-7901 cells

AIM: To investigate bhe effects of allicin on both telomerase activity and apoptosis in gastric cancer SGC-7901 cells.METHODS: The gastric cancer SGC-7901 adenocarcinoma cells were treated with allicin and the cell cycle, inhibitory rate, apoptosis, telomerase activity and morphoiogic changes were studied by MTT assay, flow cytometry (FCM), TRAP-PCR-ELISA assay, light microscope, electron microscope respectively. Results were compared with that of AZT (3′-Azido-3′deoxythymidine).RESULTS: SGC-7901 cells were suppressed after exposure to allicin of 0.016 mg/ml, 0.05 mg/ml, and 0.1 mg/ml for 48 h. Compared with the control, the difference was significant (P&lt;0.05). Allicin could induce apoptosis of the cells in a dose-dependent and non-linear manner and increase bhe propo~on of cells in the G2/M phase. Compared with the control, the difference was significant in terms of the percentage of cells in the G2/M phase (P&lt;0.05). Allicin could inhibit telomerase activity in a time-dependent and dose-dependent pattern. After exposure to allicin at 0.016mg/ml for 24 hours, SGC-790t cells showed typical morphologic change.CONCLUSION: Allicin can inhibit telomerase activity and induce apoptosis of gastric cancer SGC-7901 cells. Allicin may be more effective than AZT.     

β-榄香烯对胃癌及胃癌耐药细胞杀伤作用的实验研究

目的 研究β-榄香烯联合或不联合化学治疗药物5-氟尿嘧啶(5-FU)对人胃癌细胞株SGC-7901和相应耐药细胞株SGC-7901/5-FU的杀伤作用及机制.方法 用不同剂量β-榄香烯(20、40或80μg/ml)联合或不联合5-FU (100 μg/ml)作用于SGC-7901和SGC-7901/5-FU细胞,采用四甲基偶氮唑盐实验、透射电镜观察、流式细胞仪和DNA原位末端标记(TUNEL)法检测药物对细胞的杀伤作用及其诱导细胞凋亡的情况.通过建立SGC-7901和SGC-7901/5-FU细胞裸鼠移植瘤模型观察β-榄香烯对这两种细胞的体内杀伤作用.结果 β-榄香烯在体内、外均具有抑制SCA3-7901和SGC-7901/5-FU细胞生长的作用(P值均<0.05),一定剂量范围内具量效关系(P=0.02).透射电镜、流式细胞仪和TUNEL实验均显示β-榄香烯抑制两种胃癌细胞生长的作用与其诱导细胞凋亡有关.结论 β-榄香烯在体内外对SGC-7901和SGC-7901/5-FU细胞均具杀伤作用,该作用可能与其诱导细胞凋亡有关.     

Akt和核因子κB信号通路在胃癌细胞化学治疗耐药中的作用

目的 探讨Akt、核因子(NF)-κB信号通路在胃癌细胞化学治疗耐药中的作用,以及Akt、NF-κB信号通路的相互作用关系.方法 采用化学治疗药物阿霉素、足叶乙甙及两药联合应用Akt抑制剂(Wortmannin)或NF-κB抑制剂(MG-132)分别作用于胃癌细胞(SGC-7901).用四甲基偶氮唑盐比色法(MTT法)检测SGC-7901细胞增长率;TUNEL法和膜联蛋白V/碘化丙啶(PI)双标法检测肿瘤细胞凋亡;免疫细胞化学法检测NF-κB/P65蛋白表达;电泳迁移率实验(EMSA)法检测NF-κB-DNA结合活性的变化;Western印迹法检测磷酸化Akt或磷酸化NF-κB抑制因子(IκB)α蛋白的表达.结果 ①阿霉素和足叶乙甙均能明显抑制SGC-7901细胞的生长,并呈时间、剂量依赖性;分别联合应用Wortmannin或MG-132后能进一步抑制其生长.②化学治疗药物剂量依赖性地诱导SGC-7901细胞凋亡和NF-κB或Akt活化,联合应用MG-132或Wortmannin均能增强化学治疗药物的诱导凋亡作用和抑制NF-κB或Akt活化作用.③Wortmannin可明显抑制NF-κB的活化,而MG-132对Akt的活化无明显影响.结论 化学治疗药物诱导SGC-7901细胞凋亡的同时诱导Akt、NF-κB活化,抑制Akt、NF-κB的活化可增加化学治疗药物的疗效.     

阿司匹林对胃癌细胞株7901增殖和凋亡的影响

目的 体外观察阿司匹林（ASA）对胃癌细胞株SGC-7901细胞平殖的影响,并探讨其可能的作用机制。方法 采用噻唑蓝（MTT）法、流式细胞仪（FCM）、电镜和^3h-TdR核素标记等技术,研究ASA和SGC-7901细胞增殖的抑制和可能的机制。结果 MTT显示体外ASA对SGC-7901有细胞毒作用,与浓度和作用时间有相关性,^3H-TdR实验表明,ASA对细胞DNA合成有抑制制作。FCM显示,DNA直方图上出现典型的亚二倍体“凋亡峰”,凋亡率在7.8%-34.4%。使S期、G2/M期细胞比例升高,G1期比例下降,呈一定剂量效应关系。电镜下见典型的细胞凋亡形态学特征：细胞核染色质致密浓缩,凋亡小体形成等。结论 体外ASA对SGC-7901细胞增殖有抑制作用,可能与诱导细胞凋亡和阻止细胞周期的进展有关。     

2-(3羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖对人胃癌细胞系(SGC-7901)的诱导凋亡作用

目的 观察2-(3-羧基-t-丙酰氨基)-2-脱氧-D-葡萄糖(COADG)体外诱导人胃癌细胞(SGC-7901)凋亡的作用，探讨其可能作用机理。方法 采用MTT法，筛选药物作用最佳浓度。用流式细胞仪、琼脂糖凝胶电泳分析诱导凋亡前后的细胞DNA含量分析诱导凋亡前后的细胞DNA含量，透射电镜观察凋亡细胞的超微结构。结果 2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖能明显抑制胃癌细胞的增长，MTT法显示抑制程度具有时间和剂量效应关系，统计组问比较差异有显著性；流式细胞仪分析可见亚二倍体(Sub-G1)凋亡峰；电镜观察到凋亡小体。结论 2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖有诱导人胃癌细胞(SGC-7901)凋亡的作用。     

Synergistic effect of oxymatrine and angiogenesis inhibitor NM-3 on modulating apoptosis in human gastric cancer cells

AIM: To investigate the synergistic effect of oxymatrine(OM) and angiogenesis inhibitor NM-3 on modulatingapoptosis in human gastric cancer cell lines SGC-7901,MKN-45, MKN-74. METHODS: Human gastric cancer lines SGC-7901,MKN-45, MKN-74 were treated with OM in the absenceand presence of NM-3. The inhibitory rates weredetected by MTT assay. Synergistic effect of OM andNM-3 on the growth of survivin, bcl-2, bax and p53 inSGC-7901 cells were examined by semiquantitative RT-PCR and Western blotting, and their growth inhibitoryeffects were also observed on SGC-7901 tumor xenograftin nude mice.RESULTS: OM combined with NM-3 exhibited asynergistic inhibitory effect on the growth of SGC-7901,MKN-45 and MKN-74 cells in a time-dependent manner.Twenty-four hours after treatment with OM, NM-3 aloneand their combination, mRNA expression of survivin andbcl-2 in SGC-7901 cells decreased, p53 mRNA expressionincreased. OM (4 g/L) combined with NM-3 significantlyincreased the expression of p53 mRNA and decreasedthe expression of survivin and bcl-2 compared witheither agent alone (193% ± 34% vs 129% ± 12%;44% ± 18% vs 92% ± 18%; 36 ± 17% vs 93% ± 23%,P < 0.05). Western blotting showed that the synergisticeffect of OM and NM-3 on protein translation of survivin,bcl-2 and p 53 was in accordance with their mRNAs.Furthermore, OM/NM-3 combination obviously exhibitedantitumor growth effect in xenografted human gastriccancer cells SGC-7901 compared with either agent alone.CONCLUSION: OM combined with NM-3 has synergisticinhibitory effects on human gastric cancer cells in vitro and can suppress the growth of xenografted human gastric cancer cells SGC-7901 in vivo.     

厄洛替尼联合放疗对MKN45细胞株的影响

目的:观察厄洛替尼联合放疗对人胃癌MKN45细胞周期和凋亡的影响,了解厄洛替尼对放疗增敏的作用机制.方法:通过MTT法和集落形成实验,检测厄洛替尼和放射线对MKN45细胞的生长抑制作用,计算出半数抑制浓度(50%inhibitory concentration,IC50)和放射生物学参数平均致死剂量(mean lethal dose,D0)、准阈剂量(quasi-threshold,Dq)值,得出放射增敏比;流式细胞仪检测MKN45细胞经厄洛替尼及联合放射线处理后细胞的凋亡率及周期分布情况;Westernblot法检测厄洛替尼及联合放射线对MKN45细胞的Bax与Bcl-2蛋白表达的影响.结果:厄洛替尼及放射线均能抑制MKN45细胞的生长,随用药浓度或剂量的增高,抑制作用增强(P<0.01).厄洛替尼与放射线联合对MKN45细胞的抑制作用大于单药和单纯照射(P<0.01);两者联合使S期细胞比率明显降低,放射敏感的G2/M期和G0/G1期细胞比率明显增加(71.87±0.77vs60.72±0.26,P<0.01),细胞凋亡率增加;厄洛替尼联合放射线作用于细胞后,Bcl-2蛋白表达明显减少,Bax蛋白表达则明显增加.结论:厄洛替尼通过增加G2/M和G0/G1期细胞比率,降低Bcl-2、升高Bax蛋白表达,从而降低Bcl-2/Bax比率,增加细胞凋亡,以此提高MKN45细胞的放射敏感性.     

强力霉素对胃癌细胞SGC-7901基质金属蛋白酶-2和基质金属蛋白酶组织抑制因子-2表达的影响

背景：强力霉素对结肠癌细胞的分化和抑制作用已有报道，但其对胃癌细胞的作用尚未见报道。目的：观察强力霉素对人胃癌细胞SGC-7901的生长抑制作用及其对基质金属蛋白酶（MMP）-2和基质金属蛋白酶组织抑制因子（TIMP）-2表达的影响，探索胃癌治疗的新方法。方法：采用不同浓度的强力霉素作用于胃癌细胞SGC-7901，以噻唑蓝（MIT）法测定其细胞毒作用；逆转录聚合酶链反应（RT—PCR）法半定量测定MMP．2和TIMP-2mRNA的表达；免疫组化法观察MMP-2蛋白的表达。结果：强力霉素可抑制胃癌细胞SGC-7901的生长，具有浓度和时间依赖性（P〈0．01）。强力霉素可下调MMP-2mRNA和MMP-2蛋白的表达，上调TIMP-2mRNA的表达，具有浓度依赖性（P〈0．05）。结论：强力霉素能抑制胃癌细胞SGC-7901的生长，其作用机制可能与下调MMP-2表达、上调TIMP-2表达有关。     

Alisol B acetate induces apoptosis of SGC7901 cells via mitochondrial and phosphatidylinositol 3-kinases/Akt signaling pathways

AIM： To examine the effect of alisol B acetate on the growth of human gastric cancer cell line SGC7901 and its possible mechanism of action.
METHODS： The cytotoxic effect of alisol B acetate on SGC7901 cells was measured by 3-（4,5-dimethylthiazol- 2-yl）-2,5-diphenyltetrazolium bromide （MI-I-） assay. Phase-contrast and electron microscopy were used to observe the morphological changes. Cell cycle and mitochondrial transmembrane potential （A~Pm） were determined by flow cytometry. Western blotting was used to detect the expression of apoptosis-regulated gene Bcl-2, Bax, Apaf-1, caspase-3, caspase-9, Akt, P-Akt and phosphatidylinositol 3-kinases （PI3K）.
RESULTS： Alisol B acetate inhibited the proliferation of SGC7901 cell line in a time- and dose-dependent manner. PI staining showed that alisol B acetate can change the cell cycle distribution of SGC7901, increase the proportion of cells in G0-G1 phase and decrease the proportion of S phase cells and G2-M phase cells. Alisol B acetate at a concentration of 30 pmol/L induced apoptosis after 24, 48 and 72 h incubation, with occurrence rates of apoptotic cells of 4.36%, 14.42% and 21.16%, respectively. Phase-contrast and electron microscopy revealed that the nuclear fragmentation and chromosomal condensed, cells shrank and attachment loss appeared in the SGC7901 treated with alisol B acetate. Apoptosis of SGC7901 cells was associated with cell cycle arrest, caspase-3 and caspase-9 activation, loss of mitochondrial membrane potential and up-regulation of the ratio of Bax/Bcl-2 and inhibition of the PI3K/Akt.
CONCLUSION： Alisol B acetate exhibits an antiproliferative effect in SGC7901 cells by inducing apoptosis. Apoptosis of SGC7901 cells involves mitochondria-caspase and PI3K/Akt dependent pathways.     

RRR-α-tocopheryl succinate inhibits human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesis arrest

AIM: To investigate the effects of growth inhibition ofhuman gastric cancer SGC-7901 cell with RRR-α-tocopherylsuccinate (VES), a derivative of natural Vitamin E, viainducing apoptosis and DNA synthesis arrest.METHODS: Human gastric cancer SGC-7901 cells wereregularly incubated in the presence of VES at 5, 10 and20mg@ L 1(VES was dissolved in absolute ethanol anddiluted in RPMI 1640 complete condition mediacorrespondingly to a final concentration of VES and 1mL@L-1 ethanol), succinic acid and ethanol equivalents asvehicle (VEH) control andcondition media only asuntreated (UT) control. Trypan blue dye exclusionanalysis and MTT assay were applied to detect the cellproliferation. 37kBq of tritiated thymidine was added tocells and [3H] TdR uptake was measured to observe DNAsynthesis. Apoptotic morphology was observed byelectron microscopy and DAPI staining. Flow cytometryand terminal deoxynucleotidyl transferase-mediated dUTPnick end labeling (TUNEL) assay were performed to detectVES-triggered apoptosis.RESULTS: VES inhibited SGC-7901 cell growth in a dose-dependent manner. The growth curve showed suppressionby 24.7%, 49.2% and 68.7% following 24h of VEStreatment at 5, 10 and 20 mg@L 1, respectively, similar tothe findings from MTT assay. DNA synthesis wasevidently reduced by 35%, 45% and 98% after 24h VEStreatment at 20 mg@ L-1 and 48h at 10 and 20 mg@ L 1,respectively. VES induced SGC-7901 cells to undergoapoptosis with typically apoptotic characteristics,including morphological changes of chromatincondensation, chromatin crescent formation/margination,nucleus fragmentation and apoptotic body formation,typical apoptotic sub-G1 peak by flow cytometry andincrease of apoptotic cells by TUNEL assay in which 90%of cells underwent apoptosis after 48h of VES treatment at20 mcg@L-1.CONCLUSION: VES can inhibit human gastric cancer SGC-7901 cell growth by inducing apoptosis and DNA synthesisarrest. Inhibition of SGC-7901 cell growth by VES is dose-and time-dependent. Therefore VES can function as apotent chemotherapeutic agent against human gastriccarcinogenesis.     

Inhibitory effects of apigenin on the growth of gastric carcinoma SGC-7901 cells

AIM: To explore the growth inhibition and apoptosis-inducing effect of apigenin on human gastric carcinoma SGC-7901 cells. METHODS: The effects of apigenin on the growth, clone formation and proliferation of human gastric carcinoma SGC-7901 cells were observed by MTT, clone-forming assay, and morphological observation. Fluorescent staining and flow cytometry analysis were used to detect apoptosis of cells. RESULTS: Apigenin obviously inhibited the growth, clone formation and proliferation of SGC-7901 cells in a dosedependent manner. Inhibition of growth was observed on d 1 at the concentration of 80 μmol/L, while after 4 d, the inhibition rate (IR) was 90%. The growth IRs at the concentration of 20, 40, and 80 μmol/L were 38%, 71%, and 99% respectively on the 7~(th) d. After the cells were treated with apigenin for 48 h, the number of clone-forming in control, 20, 40, and 80 μmol/L groups was 217±16.9, 170±11.1 (P<0.05), 98±11.1(P<0.05), and 25±3.5 (P<0.05) respectively. Typical morphological changes of apoptosis was found by fluorescent staining. The cell nuclei had lost its smooth boundaries, chromatin was condensed, and cell nuclei were broken. Flow cytometry detected typical apoptosis peak. After the cells were treated with apigenin for 48 h, the apoptosis rates were 5.76%, 19.17%, and 29.30% respectively in 20, 40, and 80 μmol/L groups. CONCLUSION: Apigenin shows obvious inhibition on the growth and clone formation of SGC-7901 cells by inducing apoptosis.     

Apoptosis of human gastric cancer SGC-7901 cells induced by mitomycin combined with sulindac

AIM: To investigate the effects of mitomycin (MMC) combined with sulindac on cell viability, apoptotic induction and expression of apoptosis-related gene Bcl-2 and cyclooxygenase-2 (COX-2) in gastric cancer SGC-7901 cells. METHODS: Human gastric cancer SGC-7901 cells were divided into three treatment groups,namely sulindac treatment group, MMC treatment group and combined sulindac with MMC treatment group. After being treated with drugs, cell viability was examined by MTT assay. Flow cytometry was used to evaluate the cell cycle distribution and apoptotic rates. Morphology of the cells was observed under light microscope and interactive laser microscope. Expression of COX-2 and Bcl-2 was determined by immunocytochemical method. RESULTS: After exposure for 12 h to three kinds of drugs, gastric cancer SGC-7901 cells presented some morphological features of apoptosis, including cell shrinkage, nuclear condensation, DNA fragmentation and formation of apoptotic bodies. Growth inhibition was more obvious in combined sulindac with MMC treatment group and sulindac treatment group than in MMC treatment group. The apoptotic rates in co-treated cells and MMC-treated cells 24 h after treatment were 12.0% and 7.2%, respectively. After exposure for 24 h to MMC, the expression of COX-2 and Bcl-2 protein was up-regulated, COX-2 levels were down-regulated but Bcl-2 gene expression was not changed significantly in combined treatment group. CONCLUSION: MMC-induced apoptosis is reduced by up-regulating the expression of COX-2 and Bcl-2 genes. MMC combined with sulindac can suppress the growth of gastric cancer cells through induction of apoptosis mediated by down-regulation of apoptosis-related Bcl-2 and COX-2 gene.     

Cortactin expression confers a more malignant phenotype to gastric cancer SGC-7901 cells

AIM:To study the effects of cortactin on the tumor biology of SGC-7901 cells and identify the mechanism involved in the process.METHODS:Cell lines in which cortactin was stably overexpressed or knocked down as well as the respective control cell lines were established by standard molecular methods.The effects of cortactin on the proliferation,migration and invasion capacity of SGC-7901cells were assessed by the MTT assay,colony formation,flow cytometry,transwell migration and matrigel invasion.Nude mouse models were also used to assess the role of cortactin in the growth and metastasis of SGC-7901 cells in vivo.Western blotting analysis was performed to detect the expression of epidermal growth factor receptor(EGFR)and downstream molecules.RESULTS:Cell lines in which cortactin was stably overexpressed or knocked down as well as control cell lines were successfully established and designated as LV5-cortactin-SGC,LV5-SGC,LV3-shRNA-SGC and LV3-SGC.Cortactin overexpression promoted SGC-7901 cell migration(340.7±12.6 vs 229.1±23.2,P<0.01)and invasion(71.6±5.2 vs 48.4±3.6,P<0.01).Cortactin downregulation impaired SGC-7901 cell migration(136.2±19.8 vs 225±17)and invasion(29.2±5.2vs 49.6±3.8,P<0.01).The results from the MTT and colony formation assays results indicated increased LV5-cortactin-SGC cell proliferation and decreased LV3-shRNA-SGC cell proliferation compared to the control cells.Flow cytometry analysis demonstrated that cortactin overexpression promoted the proliferation index of SGC-7901 cells,and the results were reversed when cortactin was downregulated.Mouse tumor models confirmed that cortactin expression increased SGC-7901cell proliferation and metastasis in vivo.Western blotting analysis revealed that cortactin elevated EGFR expression and activated the downstream molecules.CONCLUSION:Cortactin expression promoted the migration,invasion and proliferation of SGC-7901 cells both in vivo and in vitro.The EGFR signaling pathway is mechanistically involved.