Effect of cis—9,trans—11—conjugated linoleic acid on cell cycle of gastric adenocarcinoma cell line（SGC—7901）

AIM: To determine the effect of cis -9, trans -11-conjugated linoleic acid (c9, t11-CLA) on the cell cycle of gastric cancer cells (SGC-7901) and its possible mechanism in inhibition cancer growth. METHODS: Using cell culture and immunocytochemical techniques, we examined the cell growth, DNA synthesis, expression of PCNA, cyclin A, B(1), D(1), p16(ink4a) and p21(cip/waf1) of SGC-7901 cells which were treated with various c9, t11-CLA concentrations (25, 50, 100 and 200 micromol.L(-1))of c 9, t 11-CLA for 24 and 48h, with a negative control (0.1% ethane). RESULTS: The cell growth and DNA synthesis of SGC-7901 cells were inhibited by c9, t11-CLA.SGC-7901 cells. Eight day after treatment with various concentrations of c9, t11-CLA mentioned above, the inhibition rates were 5.92%, 20.15%, 75.61% and 82.44%, respectively and inhibitory effect of c9, t11-CLA on DNA synthesis (except for 25 micromol.L, 24h) showed significantly less (3)H-TdR incorporation than that in the negative controls (P<0.05 and P<0.01). Immunocytochemical staining demonstrated that SGC-7901 cells preincubated in media supplemented with different c9, t11-CLA concentrations at various times significantly decreased the expressions of PCNA (the expression rates were 7.2-3.0%, 24h and 9.1-0.9% at 48h, respectively), Cyclin A (11.0-2.3%, 24h and 8.5-0.5%,48h), B(1) (4.8-1.8% at 24h and 5.5-0.6% at 48h)and D(1) (3.6-1.4% at 24h and 3.7%-0 at 48h) as compared with those in the negative controls(the expressions of PCNA, Cyclin A, B(1) and D(1) were 6.5% at 24h and 9.0% at 48h, 4.2% at 24h and 5.1% at 48h, 9.5% at 24h and 6.0% at 48h,respectively)(P<0.01), whereas the expressions of P16(ink4a) and P21(cip/waf1), cyclin-dependent kinases inhibitors(CDKI), were increased. CONCLUSION: The cell growth and proliferation of SGC-7901 cell is inhibited by c9, t11-CLA via blocking the cell cycle, with reduced expressions of cyclin A,B(1) and D(1) and enhanced expressions of CDKI(P16(ink4a) and p21(cip/waf1)).     

Blocking effects of genistein on cell proliferation and possible mechanism in human gastric carcinoma

AIM: To study the blocking effects of genistein on cell proliferation cycle in human gastric carcinoma cells (SGC-7901) and the possible mechanism. METHODS: MTT assay was applied in the detection of the inhibitory effects of genistein on cell proliferation. Flow cytometry was used to analyze the cell cycle distribution. Immunocytochemical technique and Western blotting were performed to detect the protein expression of cyclin D_1, cyclin B_1 and p21~(waf1/cip1). RESULTS: Genistein significantly inhibited the growth and proliferation of human gastric carcinoma cells (SGC-7901). Seven days after treatment with different concentrations of genistein (2.5, 5.0, 10.0, 20.0 μg/mL), the growth inhibitory rates were 11.2%, 28.8%, 55.3%, 84.7% respectively and cell cycles were arrested at the G(2)/ M phase. Genistein decreased cyclin D_1 protein expression and enhanced cyclin B_1 and p21~(waf1/cip1) protein expression in a concentration-dependent manner. CONCLUSION: The growth and proliferation of SGC-7901 cells can be inhibited by genistein via blocking the cell cycle, with reduced expression of cyclin D_1 and enhanced expression of cyclin B_1 and p21~(waf1/cip1) protein in the concentration range of 0-20 μg/mL.     

Nimesulide inhibits proliferation via induction of apoptosis and cell cycle arrest in human gastric adenocarcinoma cell line

AIM: To evaluate the potential role of Nimesulide, a selective COX-2 inhibitor, in proliferation and apoptosis of gastric adenocarcinoma cells SGC7901. METHODS: Cell counts and MTT assay were used to quantify the influence of Nimesulide in the proliferation of SGC7901 cells. Transmission electron microscopy and flow cytometry were used to observe the induction of Nimesulide the apoptosis of SGC7901 cells and influence in the distribution of cell cycle. The expression of P27(kip1) protein was observed by immunocytochemical staining. RESULTS: SGC-7901 Cells treated with Nimesulide at various concentrations exhibited a profound dose- and time-dependent reduction in the proliferation rate over the 72 h test period. The highest survival rate of the cells was 78.7 %, but the lowest being 22.7 %. Nimesulide induced apoptosis of the cells in a dose-dependent and non-linear manner and increased the proportion of cells in the G(0)/G(1) phase and decreased the proportion in the S and G(2)/M phase of the cell cycle. Meanwhile, Nimesulide could up-regulate the expression of P27(kip1) protein. CONCLUSION: The induction of apoptosis and cell cycle arrest are both anti-proliferative responses that likely contribute to the antineoplastic action of nimesulide on SGC-7901 cells. The up-regulation of P27(kip1) gene may contribute to the accumulation of these cells in the G(0)/G(1) phase following treatment with Nimesulide. Selective COX-2 inhibitor may be a new channel of the chemoprevention and chemotherapy for gastric carcinoma.     

曲古菌素A对人胃癌细胞增殖和细胞周期的作用

目的 观察曲古菌素A(TSA)对人胃癌细胞株SGC-7901细胞增殖及细胞周期的影响,探讨其可能的机制.方法 TSA干预人胃癌SGC-7901细胞24 h后.采用四甲基偶氮唑盐法检测其对细胞增殖的影响,流式细胞技术检测细胞周期,实时PCR检测细胞周期素D1和p21 mRNA的表达情况.结果 经TSA干预24 h后,人胃癌SGC-7901细胞增殖受抑制,TSA 0.1、0.5和2.0μmol/L组抑制率分别为3.52%±6.11%、13.29%±4.13%和14.24%±2.80%;同时TSA 0.5μmol/L组(71.26%±0.51%)和TSA 2.0μmol/L组(71.03%±0.12%)的G0/Gl期细胞比例明显高于对照组(51.12%±1.17%);TSA 0.5μmol/L组(13.55%±0.44%)和TSA 2.0 μmol/L组(10.63%±0.63%)的S期细胞比例明显低于对照组(34.60%±0.60%).出现G0/G1细胞周期阻滞.TSA干预后细胞周期相关基因细胞周期素D1 mRNA表达下调和p21 mRNA表达上调.结论 TSA通过调控细胞周期相关基因细胞周期素D1和p21的表达,抑制人胃癌SGC-7901细胞的增殖,引起G0/G1期细胞周期阻滞,最终影响肿瘤细胞的生长.     

Heat shock protein 70 antisense oligonucleotide inhibits cell growth and induces apoptosis in human gastric cancer cell line SGC-7901

AIM: Heat shock protein (HSP)70 is over-expressed in human gastric cancer and plays an important role in the progression of this cancer. We investigated the effects of antisense HSP70 oligomer on human gastric cancer cell line SGC-7901, and its potential role in gene therapy for this cancer. METHODS: Human gastric cancer cell line SGC-7901 was treated in vitro with various concentrations of antisense HSP70 oligonucleotides at different intervals. Growth inhibition was determined as percentage by trypan blue dye exclusion test. Extracted DNA was electrophoresed on agarose gel, and distribution of cell cycle and kinetics of apoptosis induction were analyzed by propidium iodide DNA incorporation using flow cytometry, which was also used to detect the effects of antisense oligomer pretreatment on the subsequent apoptosis induced by heat shock in SGC-7901 cells. Proteins were extracted for simultaneous measurement of HSP70 expression level by SDS-PAGE Western blotting. RESULTS: The number of viable cells decreased in a dose-and time-dependent manner, and ladder-like patterns of DNA fragments were observed in SGC-7901 cells treated with antisense HSP70 oligomers at a concentration of 10μmol/L for 48 h or 8μmol/L for 72 h, which were consistent with inter-nucleosomal DNA fragmentation. Flow cytometric analysis showed a dose- and time-dependent increase in apoptotic rate by HSP70 antisense oligomers. This response was accompanied with a decrease in the percentage of cells in the G_1 and S phases of the cell cycle, suggesting inhibition of cell proliferation. In addition, flow cytometry also showed that pretreatment of SGC-7901 cells with HSP70 antisense oligomers enhanced the subsequent apoptosis induced by heat shock treatment. Western blotting demonstrated that HSP70 antisense oligomers inhibited HSP70 expression, which preceded apoptosis, and HSP70 was undetectable at the concentration of 10 μmol/L for 48 h or 8 μmol/L for 72 h. CONCLUSION: Antisense HSP70 oligomers can abrogate HSP70 expression in SGC-7901 cells, which may in turn induce apoptosis and inhibit cell proliferation, conversely suggesting that HSP70 is required for the proliferation and survival of human gastric cancer cells under normal conditions.     

木黄酮对人胃癌细胞SGC-7901作用的研究

目的探讨木黄酮对体外培养的人胃癌细胞SGC-7901生长的抑制和诱导细胞凋亡的作用。方法用MTT法检测药物效应，透射电镜及流式细胞仪观察木黄酮处理SGC-7901细胞后细胞周期和细胞凋亡。细胞免疫化学观察木黄酮处理SGC-7901细胞后，SGC-7901细胞PCNA，FAS，C-mvc的变化。结果①MTT法证实木黄酮对SGC-7901细胞生长有抑制作用，并呈剂量-效应关系。②流式细胞仪分析木黄酮处理SGC-7901细胞后细胞滞留于G2／M期，并可见凋亡峰。③透射电镜可见SGC-7901细胞出现典型的细胞凋亡及坏死形态学改变。④木黄酮下调PCNA及C—myc表达，上调FAS表达。结论木黄酮对人胃癌细胞SGC-7901有抑制作用，其抑制作用可能通过下调C-mvc基因表达，上调Fas蛋白表达，下调PCNA表达，从而多途径诱导胃癌细胞凋亡和坏死、阻抑细胞周期进程，抑制SGC-7901细胞增殖。     

回转器模拟失重对静脉内皮细胞形态、增殖和周期的影响

目的:探讨回转器模拟失重对人脐静脉内皮细胞(HUVECs)形态、增殖和周期的影响。方法: 以HUVECs为研究对象,采用回转器模拟失重,在倒置显微镜下观察模拟失重后细胞形态的变化,用细胞计数法测定细胞的增殖情况,用流式细胞仪(FCM)测定细胞周期。结果: 模拟失重后,HUVECs多呈圆形,可见细胞重叠或聚集生长。回转器模拟失重后12 h、24 h和36 h,细胞周期明显阻滞在G0+G1期（P<0.05）,而细胞计数则无明显改变。结论: 模拟失重可使HUVECs的形态发生一定改变,使HUVECs的细胞周期阻滞。     

丙戊酸钠对肝癌SMMC-7721细胞增殖和细胞周期的影响及机制

目的:探讨丙戊酸钠(VPA)对人肝癌SMMC-7721细胞增殖、细胞周期及对p21WAF1/CIP1mRNA表达的影响.方法:实验分为空白对照组、PBS组、VPA0.2mmol/L组、VPA1.0mmol/L组和VPA5.0mmol/L组.不同浓度VPA干预人肝癌SMMC-7721细胞24h、48h和72h,采用MTT法检测细胞存活率,流式细胞仪检测细胞周期;干预72h后,用Real-timePCR法检测VPA干预72h后p21WAF1/CIP1mRNA的表达情况.结果:与空白对照组及PBS组比较,不同浓度的VPA作用24h,48h及72h时组肝癌SMMC-7721细胞增殖均出现了不同程度抑制(请将具体数据列出来P<0.05),随着VPA药物浓度升高,细胞增殖抑制作用逐渐增强,随作用时间延长,抑制程度逐渐增强(P<0.05).随药物浓度升高,G1期细胞比例逐渐增多,S期细胞比例逐渐减少,细胞发生G0/G1期阻滞.VPA干预肝癌SMMC-7721细胞72h后,VPA组p21WAF/CIP1mRNA表达较空白对照组及PBS组表达明显升高(请将具体数据列出来P<0.01).结论:VPA可抑制人肝癌SMMC-7721细胞的增殖,且呈时间及剂量依赖性,并诱导出现G0/G1细胞周期阻滞,同时上调p21WAF1/CIP1mRNA的表达.     

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.