胃癌Runx3基因的甲基化

目的:探讨Runx3基因甲基化与胃癌的关系方法:采用MSP法检测38例配对胃癌组织、癌旁正常组织和转移淋巴结中Runx3基因甲基化的情况.结果:73.7%的胃癌组织中存在Runx3基因异常甲基化,而相应的癌旁正常组织和转移淋巴结中该基因的甲基化率分别为21.1%和65.8%.癌组织和转移淋巴结中Runx3基因甲基化的发生率显著高于癌旁正常组织(P<0.05).胃癌组织中,该基因甲基化与肿瘤大小显著相关(P =0.021),但与肿瘤大体类型、分化程度、浸润深度及生长方式等临床病理特征无关.结论:Runx3基因异常甲基化是胃癌发生、发展过程中的频繁事件,通过检测胃黏膜组织及淋巴结中该基因的甲基化情况,可能会对胃癌的早期诊断及判断淋巴结的微转移提供一定的参考价值.     

维生素C诱导人胃癌细胞株MKN45凋亡的实验研究

目的 探讨维生素C对胃癌细胞株MKN45增殖、凋亡的影响及其相关机制。方法在体外培养的胃癌细胞株MKN45中加入不同浓度（0．05、0．1、0．5、1mg／m1）的维生素C,通过MTT比色法检测维生素C对细胞生长活力的影响;应用荧光显微镜、流式细胞术、DNALadder分析法检测细胞凋亡情况;应用分光光度法检测Caspase-3活性;应用化学显色法测定维生素C作用MKN4524h后细胞内超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量。结果维生素C对胃癌细胞株MKN45有显著的生长抑制作用;与对照组比较,1mg／ml维生素C处理后,细胞凋亡率升高（P〈0．01）,并呈现凋亡的形态学改变,DNALadder分析呈典型“梯状”条带;Caspase-3活性升高（P〈0．05）。与对照组相比,维生素c处理组细胞内的SOD活性下降,MDA含量增加（P〈0．05）。结论1mg／ml浓度的维生素c作用24h后,可诱导胃癌细胞MKN45凋亡,其机制可能是通过提高Caspase-3的活性以及通过自身自氧化的氧化应激效应而诱导肿瘤细胞凋亡。     

Heart involvement in lamin A/C related diseases

The LMNA gene encodes lamins A and C, components of the nuclear envelope. Its mutations cause a wide range of diseases named laminopathies involving either specific tissues in isolated fashion (cardiac and skeletal muscles, peripheral nerve, adipose tissue) or several tissues in a generalized way (premature ageing syndromes and related disorders). The striated muscle laminopathies include a variety of well clinically characterized disorders where cardiac muscle involvement represents the common feature that coexists with or without skeletal muscle disease. The cardiac disease of LMNA mutated patients is classically defined by conduction system and rhythm disturbances occurring early in the course of the disease, followed by dilated cardiomyopathy and heart failure. These features are life threatening and often responsible of cardiac sudden death. When associated, the skeletal muscle involvement is characterized by muscle weakness and wasting of variable topography with or without early joint contractures and spinal rigidity. Specific management of the cardiac disease to includes antiarrhythmic drugs, cardiac devices such as implantable cardioverter for primary and secondary prevention of sudden death, and heart transplantation at the end stage of heart failure. A large number of LMNA mutations leading to striated muscle laminopathies have been reported without so far any clear and definite phenotype/genotype relation. Finally, among the diverse hypotheses for pathomechanisms of LMNA mutations, the structural hypothesis suggesting a defective role of lamins A/C in maintaining the structural integrity of the nuclear envelope in striated muscles under constant mechanical stress is highly attractive to link the LMNA mutations and the cardiac disease.     

Steroid hormone receptors in three human gastric cancer cell lines

Steroid hormone receptors in three human gastric adenocarcinoma cell lines and their transplanted tumors (except nontumorigenic KATO-III) in nude mice were determined by dextran-coated charcoal assay. Progesterone receptors (PgR) were found in all cell lines, transplanted NUGC-3, and AZ 521 tumors. Estrogen receptors (ER) were found in KATO-III cells, transplanted NUGC-3, and AZ 521 tumors, whereas glucocorticoid receptors (GR) were found only in NUGC-3 tumor and no androgen receptor was found in any cell lines or transplanted tumors. Since NUGC-3 cells had ER, PgR, and GR, it was used for the study of the effects of steroid hormones on growth. The results showed the cell cycle phase distributions and growth rate of transplanted tumors were similar in hormone-treated and nontreated groups. The persistent expression of PgR in gastric cancer cell lines and tumors, and the slight increase of tumor volumes in the progesterone-treated group suggests that progesterone and its receptors may be important in the pathogenesis of gastric cancer, but their biological function remains to be elucidated.This study was supported by a grant from National Science Council of the Republic of China (NSC 81-0412-B075-48).     

胰腺癌细胞株原钙黏附蛋白8基因的甲基化状态

目的 分析原钙黏附蛋白8(protocadherin 8,PCDH8)基因在胰腺癌细胞株的甲基化状态.方法 抽提6株胰腺癌细胞株PANC1、ASPC1、BxPC3、CFPAC、PaTu8988、SW1990和2例正常胰腺组织的总RNA,以甲基化特异性PCR(MSP)法检测PCDH8甲基化情况.应用DNA甲基化转移酶(DNMT)抑制剂5-氮杂2'-脱氧胞苷(5-Aza-dC)处理6株胰腺癌细胞株,采用实时定量PCR法检测处理前后细胞的PCDH8 mRNA表达.结果 2例正常胰腺组织PCDH8基因未发生甲基化,PANC1、BxPC3、CFPAC胰腺癌细胞株PCDH8基因部分甲基化,而PaTu8988、ASPC1、SW1990细胞完全甲基化.PCDH8mRNA在PANC1、SW1990、PaTu8988胰腺癌细胞株中有表达,表达的相对值(RQ)分别为1.576±0.648、0.013±0.008、0.002±0.001;BxPC3、CFPAC、ASPC1细胞株无PCDH8 mRNA表达.5-Aza-dC处理后,胰腺癌细胞株PANC1、ASPC1、BxPC3、CFPAC、PaTu8988、SW1990均有PCDH8 mRNA表达,表达量较处理前明显升高,相对表达量分别为7.463±2.628、10.696±1.539、7.852±2.762、421.815±1.493、118.595±4.089、6.690±1.884.结论 PCDH8基因启动子高甲基化是导致该基因在胰腺癌细胞株表达下降的主要原因之一.     

温热体外对人胃癌细胞株生物学行为的影响

目的:探讨温热对人胃癌细胞株增殖、生存以及黏附、侵袭能力的影响．方法:对人胃癌细胞株(AGS,MKN45, SGC7901,NCI-N87,SNU-1和SNU-16)行43℃ 2h的温热处理,以37℃常温培养为对照．处理后用MTT法绘制生长曲线并比较增殖抑制情况;光镜下动态观察细胞生长情况和形态学变化;Hoechst33342/PI荧光染色观察细胞核染色等形态学变化:透射电镜(transmission electron microscopy,TEM)观察细胞超微结构和死亡的具体形式;流式细胞术(flow cytometry,FCM)定量分析细胞的凋亡和坏死比例;黏附和侵袭试验观察胃癌细胞的黏附和侵袭能力．结果:MTT提示,温热对SNU-1有显著的增殖抑制作用(P<0．01),对SNU-16则无显著影响(P>0．05),对4株贴壁细胞则表现为暂时性的增殖抑制(d1-d2,P<0．05);光镜观察发现温热处理后SNU-1细胞出现死亡,而其他细胞无;荧光染色和透射电镜未发现AGS在温热处理后24h有显著的形态学改变,而SNU-1则出现凋亡和坏死;FCM提示温热处理不增加 AGS的自然死亡率(t=0．45,P=0．678 8),但能诱导SNU-1发生凋亡和坏死,增加细胞死亡率(9．7％±1．1％vs 20．1％±2．5％,t=6．54, P=0．002 8);黏附试验表明温热能不同程度降低4株贴壁细胞的黏附能力[AGS(t=4．86, P=0．008 3),MKN45(t=4．50,P=0．0108), SGC7901(t=6．83,P=0．002 4),N87(t=4．16, P=0．014 1)1;侵袭试验表明温热能不同程度降低6株细胞的侵袭能力[AGS(t=2．94, P=0．042 5),MKN45(t=3．60,P=0．022 7), SGC7901(t=4．70,P=0．0093),N87(t=12．41, P=0．0002),SNU-1(t=3．63,P=0．022 2), SNU-16(t=4．13,P:0．0145)]．结论:大多数的胃癌细胞株表现对短时间温热的耐受,除了暂时性的增殖抑制作用外,温热并无细胞杀伤作用,SNU-1是一个例外,温热能导致SNU-1细胞的凋亡和坏死;同时,温热处理能降低细胞的黏附和侵袭能力．     

肝癌细胞中OY-TES-1基因启动子的甲基化状态

目的:研究肝癌细胞株OY-TES-1启动子的甲基化状态及甲基转移酶抑制剂对其启动子甲基化的影响.方法:运用生物信息学在线软件预测OY-TES-1启动子区域及转录因子结合位点;应用亚硫酸氢盐测序法(bisulfite-sequencing PCR,BSP)分析目的基因CpG位点的甲基化状态;用甲基转移酶抑制剂5-Aza-...     

人巨噬细胞金属弹性蛋白酶在胃癌细胞株及胃癌组织中的表达及意义

目的测定人巨噬细胞金属弹性蛋白酶（HME）在胃癌细胞及胃癌组织中的表达,评价其在胃癌进展中的作用.方法2003年4月至8月胃肠外科和肿瘤外科胃癌住院手术病人共58例,所有病人均取肿瘤组织、癌旁组织、远处正常组织标本,采用R-PCR、实时荧光定量PCR测定胃癌细胞株（MGC-803、SGC-7901、AGS）及胃癌组织中HME mRNA水平,采用Western印迹和免疫组化法测定HME蛋白水平.结果3株胃癌细胞株中均有HME mRNA和蛋白表达;胃癌组织中的HMEmRNA和蛋白表达高于远处正常组织,差异有统计学意义（P＜0.05）;而胃癌组织与癌旁组织中的HME mRNA和蛋白表达差异无统计学意义（P＞0.05）.结论胃癌患者中HME mRNA和蛋白呈一定比例的阳性表达,胃癌组织中最高,其次为癌旁组织和远处正常组织,说明HME是一项有潜在价值的肿瘤相关标志物.     

PEBP1基因对胃癌细胞生物学特性影响的体外实验研究

目的探讨PEBP1基因对于胃癌细胞增殖状态、细胞周期、凋亡状态等生物学特性及成瘤、浸润转移能力等恶性表型的影响。方法将PEBP1基因插入载体pcDNA3.1构建PC-PEBP1真核表达载体。脂质体转染胃癌细胞系MKN45建立稳定转染细胞系(MKN-PEBP1),而后使用生长曲线法、平板克隆形成实验法、流式细胞仪、细胞迁徙实验法等分析稳定表达株相关生物学特性变化。同时设立pcDNA3.1空载体转染组(MKN-PC)和空白MKN45细胞组(MKN45)为对照。结果与MKN-PC组和MKN45组相比,转染MKN-PEBP1载体的稳定表达细胞株生长显著减慢,MKN-PC组和MKN45组之间无显著差异,平板克隆形成实验结果显示,MKN-PEBP1转染组平均克隆形成率显著低于MKN-PC组和MKN45组(P<0.05),细胞周期检测显示MKN-PEBP1组处于G0/G1期的细胞比例显著高于未处理的MKN45组细胞和MKN-PC组细胞(P<0.05),而处于G2-M期的细胞比例显著均低于其他两组(P<0.05),其他各期细胞比例均无显著差异。流式细胞仪法检测细胞凋亡结果显示各组细胞的凋亡比例均为2.0%左右,统计学检验无显...     

叶酸对胃癌细胞凋亡的影响

目的胃癌的发生与发展中有细胞凋亡的变化,叶酸抗肿瘤的机理涉及到维持ＤＮＡ甲基化水平等,其与凋亡的关系尚未明了。方法以高低两种浓度的叶酸干预培养的人胃癌ＭＫＮ－４５和ＭＫＮ－２８细胞系７２小时后,以原位ＤＮＡ断端切口标记法和ＤＮＡ琼脂糖凝胶电泳检测凋亡形态学改变和ＤＮＡ断裂情况。结果未加干预者两种细胞系的凋亡指数均低于５％,不同分化细胞系间比较差异无显著性;低浓度叶酸可诱导ＭＫＮ－４５细胞凋亡,而高浓度者使ＭＫＮ－２８细胞凋亡率增加。结论胃癌细胞自然凋亡率较低。叶酸干预可影响凋亡的发生。     

Methylation of Herpesvirus saimiri DNA in lymphoid tumor cell lines

Several continuous lymphoid cell lines have been established from tumors induced by Herpesvirus saimiri. At least a portion of the viral DNA in the marmoset lymphoid cell line 1670, which does not produce detectable virus, is present as covalently closed circular episomal DNA. The use of restriction endonuclease digestion, transfer to nitrocellulose filters, and hybridization of the virus-specific DNA has produced strong evidence that viral DNA sequences present in total 1670 cell DNA and in isolated episomes are extensively methylated. The restriction endonuclease Hpa II has the same recognition sequence as Msp I but, unlike Msp I, fails to cleave when the C of the C-G dinucleotide is methylated. Viral DNA sequences of 1670 cells are refractory to cleavage by Hpa II but not Msp I; greater than 80% of the Hpa II cleavage sites appear to be methylated. Similarly, viral DNA sequences of 1670 cells are refractory to cleavage by Sma I (C-C-C-G-G-G) and Sac II (C-C-G-C-G-G) but not Sac I, Pvu II, or Pst I, which lack the dinucleotide C-G in their recognition sequences. Methylation of mammalian DNA has been previously found exclusively at C residues in the dinucleotide C-G. H. saimiri DNA sequences of another nonproducer cell line, 70N2, also appeared to be extensively methylated, but analysis of total cell DNA extracted from three virus-producing lymphoid lines revealed no evidence of methylation of viral DNA sequences. It remains to be seen if methylation of viral DNA plays a role in the lack of complete expression of H. saimiri genome information in nonproducing lymphoid cell lines.     

PUMA基因在胃癌组织及细胞中的表达

目的:研究p53正向细胞凋亡调控因子(PUMA)基因的四种剪接体(PUMA-α,-β,-γ及-δ)在胃癌组织及细胞中的表达特点.方法:应用生物信息学分析PUMA基因四种剪接体的结构特点;同时利用半定量逆转录聚合酶链反应(RT-PCR)检测胃癌组织、癌旁组织及不同胃癌细胞系BGC-823和SGC-7901细胞中四种剪接体的mRNA表达水平.结果:PUMA-α和-β在癌旁组织中表达阳性,但在癌组织中表达难以检测,差异显著(t=9.492,15.875,均P<0.05);PUMA-γ和-δ在癌旁及癌组织中均可见表达,且在癌旁组织中的表达量显著高于癌组织(t=4.823,4.056,P<0.05).PUMA-α,-γ及-δ在胃癌不同分化程度的细胞系BGC-823(低分化)及SGC-7901(中分化)中均有表达,但两细胞系间无统计学差异.而PUMA-β在BGC-823中的表达明显高于SGC-7901细胞(t=8.710,P<0.05).结论:PUMA四种剪接体在胃癌组织中的表达下调,与癌的发生呈负相关;PUMA-β的表达还可能与细胞的分化程度有关.     

MUC2基因甲基化在胰腺癌细胞株、胰腺癌患者外周血中的检测及意义

目的 检测MUC2基因在胰腺癌细胞株、胰腺癌患者外周血中的甲基化情况,探讨MUC2基因甲基化对胰腺癌早期诊断的价值.方法 收集长海医院消化内科实验室保存的人胰腺癌细胞系SW1990、ASPC、PANC1、BxPC3、PaTu8988、CFPAC1及40例胰腺癌、15例慢性胰腺炎患者和25例正常对照者外周血标本,应用甲基化敏感性限制性内切酶(methylation-sensitive restriction endonuelease,MS-RE)为基础的PCR法检测MUC2基因甲基化.结果 人胰腺癌细胞系PANC1、BxPC3、PaTu8988未发生MUC2基因甲基化;ASPC、CFPAC1、SW1990胰腺癌细胞系发生MUC2基因甲基化.外周血标本中,40例胰腺癌标本甲基化率为40.0%(16例),15例慢性胰腺炎无甲基化,25例正常对照甲基化率4.0%(1例).胰腺癌与慢性胰腺炎、正常对照之间的甲基化率有显著差异(P＜0.01).外周血标本MUC2基因启动子CpG岛甲基化检测诊断胰腺癌的敏感性为40%、特异性为97.5%、诊断准确性68.8%、阳性预测值94.1%、阴性预测值61.9%.结论 用甲基化限制性酶切PCR法对外周血进行MUC2基因启动子区高甲基化检测可望成为新的胰腺癌诊断的重要实验室辅助手段.     

氧化砷诱导胃癌细胞凋亡的实验研究

目的 研究三氧二化砷（氧化砷）对胃癌细胞的诱导凋亡作用。方法 应用ＴＵＮＥＬ染色、流式细胞仪技术研究氧化砷对胃癌细胞ＭＫＮ－４５、ＭＫＮ－２８的诱导凋亡作用。结果 氧化砷作用于不同分化程度的胃癌细胞后,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,呈新月型紧贴于核膜周边,核碎裂,染色质片断化,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”。ＴＵＮＥＬ染色法     

罗格列酮对人胃癌细胞系迁移侵袭的抑制及其机制

目的:探讨罗格列酮对人胃癌SGC7901、SGC7901/VCR细胞侵袭转移能力及LIMK1基因蛋白表达的影响.方法:罗格列酮(40 mg/L)作用SGC7901和SGC7901/VCR细胞24 h后,采用划痕实验和Transwell实验分别观察罗格列酮对细胞的迁移和侵袭能力.RT-PCR检测LIMKl mRNA和co...