奥曲肽抑制人胃癌细胞生长的研究

目的：研究生长抑素类似物奥曲肽(OCT)对胃癌SGC7901细胞的抑制作用及其作用机制。方法：不同浓度的OCT作用于体外培养的人胃癌SGC；7901细胞，应用MTT法分析细胞生长抑制作用；流式细胞仪测定细胞周期分布和凋亡率；光镜观察细胞形态等。结果：OCT在0．005μg／mL～20．0μg／mL浓度范围内呈剂量依赖方式抑制胃癌SGC7901细胞的生长增生，OCT(0.25μg／mL～5．0μg／mL)作用48h后，光镜可见SGC7901细胞呈典型的凋亡形态学改变；流式细胞仪检测出现凋亡峰。其测得的细胞凋亡率以及图像分析系统计算的细胞凋亡率与对照组相比均有显著性差异(P＜0．05)。结论：OCT对人胃癌细胞增生具有抑制作用，其机制与诱导肿瘤细胞的凋亡有关。     

奥曲肽对人胃癌细胞株SGC-7901生长的影响

奥曲肽是一种生长抑素的八肽类似物.近年发现,奥曲肽对多种胃肠道肿瘤有抑制作用 [1～ 3]. 为了进一步了解奥曲肽对胃癌细胞生长的影响,探讨其治疗胃癌的可能性,我们选用人中分化胃癌细胞株 SGC-7901,采用噻唑氮蓝(MTT)比色分析法,研究 6种浓度的 17肽促胃液素(G-17) 及奥曲肽对 SGC-7901细胞生长的影响及其作用机制,以期为临床应用提供依据. 1 材料和方法 1.1 主要试剂 G-17和 MTT(四甲基偶氮唑蓝 )均购自 Sigma公司,奥曲肽由瑞士 Sandoz药厂惠赠.RPMI-1640购自 Gibco公司,人胃癌细胞株 SGC-7901由第三军医大学附属西南医院消化内科实验室提供.DMSO为上海硫酸厂产品,胰蛋白酶(trypsin) 购自华美公司,胎牛血清购自华西生物制品厂.     

奥曲肽对人胃癌细胞SGC7901生长及凋亡作用的研究

[目的]研究生长抑素类似物奥曲肽(octreotide,OCT)对胃癌SGC7901细胞生长及凋亡的调控作用及其作用机制.[方法]用OCT作用于体外培养的人胃癌SGC7901细胞,应用MTT比色法分析细胞生长抑制作用,流式细胞仪测定细胞周期分布和凋亡率,光镜观察细胞形态等.[结果]OCT在(0.005～20.0)μg/ml浓度范围内呈剂量依赖方式抑制胃癌SGC7901细胞的生长增殖,OCT(O.25～5.0)μg/ml作用48h后,光镜可见SGC7901细胞呈典型的凋亡形态学改变;流式细胞仪检测出现凋亡峰,其测得的细胞凋亡率以及图像分析系统计算的细胞凋亡率与对照组相比均有显著性差异(P＜0.05).[结论]OCT对人胃癌细胞增殖具有抑制作用,其机制与诱导肿瘤细胞的凋亡有关.     

奥曲肽对人胃癌BGC-823细胞增殖和凋亡影响的研究

目的:研究生长抑素类似物奥曲肽(octreotide,OCT)对胃癌BGC-823细胞增殖、凋亡、细胞周期的影响及其可能的作用机制.方法:不同浓度的OCT作用于体外培养的人胃癌BGC-823细胞,以5-FU作为阳性对照,应用MTT法分析细胞增殖的抑制作用,流式细胞仪测定细胞周期分布和凋亡率,AO-EB染色观察细胞形态变化.结果:OCT对BGC-823细胞的生长、增殖产生抑制作用,该抑制作用具有量效、时效关系和饱和性;OCT作用后细胞呈典型的凋亡形态学改变,流式细胞仪检测的细胞凋亡率和AO-EB染色测得细胞凋亡率与对照组相比较差异有显著性(P<0.05);BGC-823细胞经OCT作用后,G1期细胞数明显增加,S细胞数明显减少,细胞被阻滞于G1/S 期.结论:10-5-10-3g/L 浓度的OCT能够抑制胃癌BGC-823细胞增殖,机制可能与其诱导肿瘤细胞的凋亡和出现G1/S期阻滞有关.     

奥曲肽抑制人肝癌细胞生长机制的探讨

生长抑素对肿瘤细胞的抑制作用受到人们越来越多的观注。奥曲肽 (Ｏｃｔｒｅｏｔｉｄｅ ,ＳＭＳ 2 0 1 995 )是体外合成的一种生长抑素 8肽。同天然的生长抑素 14肽相比 ,Ｏｃｔｒｅｏｔｉｄｅ具有作用更强、血浆半衰期长、作用时间更持久、使用方便等优点。近来的研究显示 ,Ｏｃｔｒｅｏｔｉｄｅ能抑制原发性肝癌的生长 ,且效果良好[1] ,但作用机理尚未明了[2 ] 。为此 ,我们观察在体外Ｏｃｔｒｅｏｔｉｄｅ能否诱导人肝癌细胞凋亡 ,从诱导肿瘤细胞凋亡的角度探讨其抑癌机理。一、材料与方法1 主要试剂与药物 :ＤＭＥＭ培养液 (美国Ｇｉｂ…     

奥曲肽诱导乳腺肿瘤细胞凋亡的实验研究

目的初步阐明奥曲肽（Ｏｃｔｒｅｏｔｉｄｅ，ＳＭＳ２０１，９９５，商品名：善得定）与乳腺肿瘤细胞凋亡的关系。方法取手术切除的１６例女性乳腺癌标本，制备肿瘤单细胞悬液，加入善得定（０．１μｇ／ｍｌ）和三苯氧胺（１μｇ／ｍｌ），用ＤＮＡ断端标记法（ＴＤＴ法）分析药物及ＥＲ、ＰＲ对乳腺肿瘤细胞凋亡的影响。结果加入善得定４小时后凋亡率为１０．６±６．９％，１８小时为１４．３±８．８％，ＥＲ（＋）ＰＲ（＋）组４小时善得定凋亡率为１４．３±５．７％，１８小时为２０．２±７．１％，加用三苯氧胺后１８小时组凋亡率为２６．３±８．９％，而ＥＲ（－）ＰＲ（－）组４小时善得定组凋亡率为４．４±３．０％，１８小时为６．５±４．０％，加用三苯氧胺后１８小时组凋亡率为８．８±４．１％，与ＥＲ（＋）ＰＲ（＋）组相比有明显差异（Ｐ＜０．０５）。结论善得定可诱导乳腺肿瘤细胞凋亡，且短时间内即可达到一定的凋亡率，善得定对ＥＲ（＋）ＰＲ（＋）的乳腺肿瘤细胞较敏感，而对ＥＲ（－）ＰＲ（－）组则基本无影响，善得定加用三苯氧胺的治疗有望成为乳腺癌患者术后一个新的辅助生物治疗手段     

奥曲肽对人胃癌BGC-823细胞增殖和凋亡影响的研究

目的：研究生长抑素类似物奥曲肽（octreotide,OCT）对胃癌BGC-823细胞增殖、凋亡、细胞周期的影响及其可能的作用机制。方法：不同浓度的OCT作用于体外培养的人胃癌BGC-823细胞,以5～FU作为阳性对照,应用M1Tr法分析细胞增殖的抑制作用,流式细胞仪测定细胞周期分布和凋亡率,AO—EB染色观察细胞形态变化。结果：OCT对BGC-823细胞的生长、增殖产生抑制作用,该抑制作用具有量效、时效关系和饱和性;OCT作用后细胞呈典型的凋亡形态学改变,流式细胞仪检测的细胞凋亡率和AO—EB染色测得细胞凋亡率与对照组相比较差异有显著性（P〈0．05）;BGC-823细胞经OCT作用后,G1期细胞数明显增加,S细胞数明显减少,细胞被阻滞于G1／S期。结论：10^-5-10^-3g/L浓度的OCT能够抑制胃癌BGC-823细胞增殖,机制可能与其诱导肿瘤细胞的凋亡和出现G1／S期阻滞有关。     

NS-398联合奥曲肽对人结肠癌细胞生长影响的研究

目的：探讨联合应用选择性环氧合酶-2（cyclooxyenase-2,COX-2）抑制剂NS-398与奥曲肽对人结肠癌细胞增殖和凋亡的影响。方法：体外培养人结肠腺癌Lovo细胞,分别用NS-398（100μmol／L）和奥曲肽（1μmol／L）单独及联合处理24、48和72h后,采用MTT法检测细胞的增殖,透射电镜观察细胞凋亡形态学变化,流式细胞仪检测细胞凋亡率和细胞周期改变,RT-PCR检测COX-2基因的表达。结果：NS-398和奥曲肽对Lovo肿瘤细胞的生长具有明显的抑制作用（P〈0．05）,且存在时间依赖性,联合应用组抑制效应明显高于单一用药组（P〈0．05）。透射电镜观察可见典型的细胞凋亡形态改变。NS-398联合奥曲肽诱导Lovo细胞的凋亡率明显高于单一用药组和对照组。细胞周期分析表明,与对照组比较,各处理组S期细胞比例降低,G0/G1期细胞比例增高（P〈0．05）。各处理组均使Lovo细胞COX-2基因mRNA表达下调（P〈0．05）。结论：NS-398联合奥曲肽可协同抑制人结肠腺癌Lovo细胞增殖并诱导其凋亡,其机制可能与细胞周期阻滞和下调COX-2基因表达有关。     

外源性FHIT基因对奥曲肽诱导胃癌细胞MGC-803凋亡的影响

目的:探讨外源性脆性组氨酸三联体(fragile histidine triad, FHIT)基因对奥曲肽(octreotide)诱导胃癌细胞凋亡的影响,并探讨其作用机制.方法:采用脂质体法将带有FHIT基因的表达载体pRcCMV-FHIT和空载体pRcCMV分别转入FHIT表达缺失的人类胃癌细胞系MGC-803中.Western 印迹法检测转染细胞中FHIT蛋白的表达.使用不同浓度的奥曲肽(10~(-10)、10~(-9)、10~(-8) 、10~(-7)和10~(-6)mol/L)分别处理各组细胞24、48 和72 h, MTT法检测分析细胞增殖情况,FCM法检测细胞凋亡. Western印迹法检测奥曲肽作用细胞前后,细胞中bcl-2和bax的表达.结果:转染FHIT基因后,胃癌细胞系MGC-803中检测到FHIT蛋白的表达.奥曲肽(10~(-8) mol/L)处理细胞48 h后,转染FHIT基因组细胞的凋亡率为(26.777±1.702)%,与转染空载体组的(13.800±0.511)%和空白细胞组的(12.634±0.479)%相比,凋亡率明显增高(F=245.789,P<0.05,).转染FHIT基因组细胞经奥曲肽处理后bcl-2蛋白表达量减少,bax蛋白表达量增加.结论:外源性FHIT基因表达与奥曲肽可协同促进胃癌细胞MGC-803凋亡,其机制可能与bcl-2家族中的凋亡相关蛋白改变有关.     

P53基因,奥曲肽与大肠肿瘤细胞凋亡的关系

Ｐ５３基因、奥曲肽与大肠肿瘤细胞凋亡的关系郑民华王灏郁宝铭张浩波李宏为林言箴关键词奥曲肽５－氟尿嘧啶大肠肿瘤细胞凋亡作者单位：上海第二医科大学附属瑞金医院外科（上海２０００２５）大肠癌为我国常见的恶性肿瘤，辅助性化疗在其治疗中占有很重要的地位。目前普...     

Direct effects of octreotide, galanin and serotonin on human colon cancer cells

The effects of mono, duple and triple treatment with octreotide, galanin and serotonin on a human colon cancer cell line (SW 620) were investigated. The cancer cells were exposed to a dose corresponding to 20 microg/kg body weight/day, and to 50 and 25% of this dose (0.2, 0.1 and 0.05 microg/ml). The cells were observed at the intervals: 3, 6, 12, 24 and 48 h. MTT-assay was used to determine numbers of viable cells. Proliferation and apoptosis were detected by immunocytochemistry using the avidin-biotin complex (ABC) method. The antibodies used were anti-Ki-67, anti-poly (ADP-ribose) polymerase 'PARP' and anti-Bcl-x. Proliferative and apoptotic indices were determined by computerized image analysis. Almost all the mono and duple treatments of the bioactive substances succeeded in reducing the numbers of viable cells. With triple treatment, however, this decrease was greater and was evident at all observation times. The effect on proliferation varied between none, and an enhancing or inhibiting action, depending on the dose, combination and observation time. The effect on apoptosis of mono or duple exposure to the bioactive gut substances varies, depending on the concentration, combination and observation time. Triple combination at the effective dose increased the apoptotic index, with the two markers used, and appeared after 6 h, extending up to 48 h. The reduction in the number of viable cancer cells was greater and occurred earlier than the increase in apoptosis and was observed whether the bioactive substances were used alone or in combinations and at different concentrations. It is therefore conceivable that some other mechanism(s) than apoptosis is involved which inhibits cancer cell respiration. It is possible that some of the dramatic in vivo changes seen earlier, following triple treatment with octreotide, galanin and serotonin, may have been direct effects of these substances on cancer cells.     

Astragalus saponins induce growth inhibition and apoptosis in human colon cancer cells and tumor xenograft

Astragalus memebranaceus is used as immunomodulating agent in treating immunodeficiency diseases and to alleviate the adverse effects of chemotherapeutic drugs. In recent years, it has been proposed that Astragalus may possess anti-tumorigenic potential in certain cancer cell types. In this study, the anti-carcinogenic effects of Astragalus saponin extract were investigated in HT-29 human colon cancer cells and tumor xenograft. Our findings have shown that Astragalus saponins (AST) inhibit cell proliferation through accumulation in S phase and G2/M arrest, with concomitant suppression of p21 expression and inhibition of cyclin-dependent kinase activity. Besides, AST promotes apoptosis in HT-29 cells through caspase 3 activation and poly(ADP-ribose) polymerase cleavage, which is indicated by DNA fragmentation and nuclear chromatin condensation. Nevertheless, we also demonstrate the anti-tumorigenic effects of AST in vivo, of which the reduction of tumor volume as well as pro-apoptotic and anti-proliferative effects in HT-29 nude mice xenograft are comparable with that produced by the conventional chemotherapeutic drug 5-fluorouracil (5-FU). In addition, the side effects (body weight drop and mortality) associated with the drug combo 5-FU and oxaliplatin are not induced by AST. These results indicate that AST could be an effective chemotherapeutic agent in colon cancer treatment, which might also be used as an adjuvant in combination with other orthodox chemotherapeutic drugs to reduce the side effects of the latter compounds.     

Cisplatin-induced apoptosis involves membrane fluidification via inhibition of NHE1 in human colon cancer cells

We have previously shown that cisplatin triggers an early acid sphingomyelinase (aSMase)-dependent ceramide generation concomitantly with an increase in membrane fluidity and induces apoptosis in HT29 cells. The present study further explores the role and origin of membrane fluidification in cisplatin-induced apoptosis. The rapid increase in membrane fluidity following cisplatin treatment was inhibited by membrane-stabilizing agents such as cholesterol or monosialoganglioside-1. In HT29 cells, these compounds prevented the early aggregation of Fas death receptor and of membrane lipid rafts on cell surface and significantly inhibited cisplatin-induced apoptosis without altering drug intracellular uptake or cisplatin DNA adducts formation. Early after cisplatin treatment, Na+/H+ membrane exchanger-1 (NHE1) was inhibited leading to intracellular acidification, aSMase was activated, and ceramide was detected at the cell membrane. Treatment of HT29 cells with Staphylococcus aureus sphingomyelinase increased membrane fluidity. Moreover, pretreatment with cariporide, a specific inhibitor of NHE1, inhibited cisplatin-induced intracellular acidification, aSMase activation, ceramide membrane generation, membrane fluidification, and apoptosis. Finally, NHE1-expressing PS120 cells were more sensitive to cisplatin than NHE1-deficient PS120 cells. Altogether, these findings suggest that the apoptotic pathway triggered by cisplatin involves a very early NHE1-dependent intracellular acidification leading to aSMase activation and increase in membrane fluidity. These events are independent of cisplatin-induced DNA adducts formation. The membrane exchanger NHE1 may be another potential target of cisplatin, increasing cell sensitivity to this compound.     

Bcl-XL siRNA抑制人结肠癌细胞生长的研究

目的:探讨应用siRNA技术下调Bcl-XL对人结肠癌细胞生长的抑制作用。方法:采用人结肠癌细胞株DLD1, 利用人工合成的Bcl-XL靶向小分子干扰RNA(siRNA)转染DLD1细胞,通过Western blot法检测转染细胞Bcl-XL蛋白的表达,流式细胞仪检测处理后细胞的凋亡情况,锥虫蓝染色法计数存活细胞。结果:与空白组和对照组相比,转染Bcl-XL siR- NA组的Bcl-XL蛋白表达显著性下降,凋亡细胞的数量显著增加(P<0．05),细胞存活率显著降低(P<0．05)。结论:Bcl-XL siRNA能显著降低人结肠癌细胞的Bcl-XL蛋白表达,有效抑制细胞的生长,为结肠癌的治疗提供了一种新的治疗策略。     

Activation of the PPAR pathway induces apoptosis and COX-2 inhibition in HT-29 human colon cancer cells

The gamma isoform of the peroxisome proliferator-activated receptor (PPARgamma) is a nuclear receptor that regulates adipocyte differentiation. Recently it has been shown to be expressed in human colonic mucosa and cancer, but its role in colon carcinogenesis and progression is still unclear. We demonstrate that activation of PPARgamma by ciglitazone (cig), a selective PPARgamma ligand, induces HT-29 human colon cancer cells to undergo apoptosis. Treatment with cig also down-regulates expression of cyclooxygenase-2 (COX-2) protein. Simultaneous exposure of cells to cig and 9-cis-retinoic acid (9-cis-RA), a ligand for retinoid X receptor, results in an increased apoptotic effect and increased inhibition of COX-2 expression, compared with cells treated with either cig or 9-cis-RA alone. As COX-2 is overexpressed in human colon cancer and has been implicated in augmenting invasiveness and tumorigenecity, the ability of PPARgamma activation to decrease COX-2 expression and induce apoptosis suggests that the PPARgamma pathway may be considered as a therapeutic target for colon cancer.     

冬凌草甲素诱导结肠癌细胞凋亡的机制研究

目的:观察冬凌草甲素(oridonin)对人结肠癌细胞HCT-116和HT-29的凋亡抑制作用,同时探讨其诱导结肠癌细胞凋亡作用的机制.方法:应用Cell-counting kit-8检测冬凌草甲素对HCT-116和HT-29细胞的生长抑制作用及对细胞活力的影响;采用烟酸己可碱(hoechst)33342和碘化丙啶(propidium lodine,PI)荧光染色法,观察冬凌草甲素诱导结肠癌HCT-116和HT-29细胞凋亡的形态学变化;采用总NO检测试剂盒与活性氧(reactive oxygen species,ROS)检测试剂盒检测冬凌草甲素处理HCT-116和HT-29细胞时,细胞内NO与ROS水平的变化;同时应用ROS阻断剂N-乙酰基半胱氨酸(N-acetyl-cysteine,NAC)预处理HCT-116、HT-29细胞后再加入冬凌草甲素,观察细胞凋亡情况.结果:冬凌草甲素可明显抑制HCT-116和HT-29细胞的增殖、降低细胞活力;Hoechst 33342和PI双荧光染色发现冬凌草甲素可诱导HCT-116和HT-29细胞的凋亡.虽然冬凌草甲素不能改变HCT-116、HT-29细胞内的NO水平,但是可提高HCT-11和HT-29细胞内ROS水平;ROS阻断剂NAC可阻断冬凌草甲素诱导HCT-116和HT-29细胞凋亡. 结论:冬凌草甲素通过提高ROS水平诱导HCT-116和HT-29细胞的凋亡.     

Securin depletion sensitizes human colon cancer cells to fisetin-induced apoptosis

Securin is highly-expressed in various tumors including those of the colon. In this study, the role of securin in the anticancer effects of fisetin on human colon cancer cells was investigated. Fisetin-induced apoptosis in HCT116 cells as indicated by TUNEL assay, Annexin V-FITC/PI double staining, Ser15-phosphorylation of p53, and cleavages of procaspase-3 and PARP. These effects were enhanced in HCT116 securin-null cells or in wild-type cells in which securin was knockdown by siRNA, but attenuated when wild-type or non-degradable securin was reconstituted. Moreover, fisetin did not induce apoptosis in HCT116 p53-null and HT-29 p53-mutant cells. Knockdown of securin in HCT116 p53-null cells potentiated fisetin-induced cytotoxicity by induction of apoptosis. Our results provide the first evidence to support that securin depletion sensitizes human colon cancer cells to fisetin-induced apoptosis.