Ndrg2基因表达对胃癌细胞增殖调控及其机理的研究

为研究Ndrg2基因在人类肿瘤发生发展中的作用,以不表达Ndrg2基因的胃癌细胞系HGC-27和表达Ndrg2基因的胃癌细胞系SGC-7901作为对比材料,以Ndrg2基因转染HGC-27胃癌细胞系,以及用Ndrg2的反义寡核苷酸封闭SGC-7901胃癌细胞系中Ndrg2基因的表达.发现Ndrg2可以抑制HGC-27胃癌细胞的软琼脂集落形成,有一定诱导细胞凋亡的作用,对细胞周期蛋白E的表达有明显下调作用.当封闭了SGC-7901胃癌细胞中Ndrg2基因表达的软琼脂集落形成受到抑制,流式细胞仪检测发现此时的SGC-7901细胞周期被阻滞在G1期,细胞周期蛋白D1和E表达下调.Ndrg2基因对两种肿瘤细胞中的细胞外信号调节激酶(ERK)和P38的表达也有不同的影响.     

肺癌中Hsa-miR-98靶基因生物信息学分析

[目的]分析肺鳞癌中Hsa-miR-98的靶基因及参与的生物学过程和信号通路。[方法]分析TCGA中收录的肺鳞癌患者的Hsa-miR-98及生存数据,通过4个靶基因数据库和表达数据分析Hsa-miR-98靶基因,利用Bi NGO富集分析靶基因功能,通过DAVID数据库富集分析靶基因信号通路。[结果]高表达Hsa-miR-98延长肺鳞癌患者总生存率和无复发生存率。综合4个数据库分析结果,得到Hsa-miR-98的113个靶基因,其中82个在肺鳞癌患者癌与癌旁差异表达。GO分析表明4个基因参与细胞胶原的组成,59个基因参与细胞的生命活动,KEGG通路富集到7条通路,包括肿瘤发生发展、阿米巴运动、胞外基质的形成等。[结论]82个Hsa-miR-98靶基因通过7条信号通路,影响细胞生命活动,进而调控肿瘤发生发展,使高表达Hsa-miR-98患者生存期延长。     

HMGB1在胃癌组织及细胞系中表达的研究

目的:近年来的研究表明,高迁移率族蛋白(1HMGB1)在肿瘤的发生及恶性演变过程中发挥重要作用,本研究旨在探讨HMGB1在胃癌组织、正常组织、胃癌细胞系SGC-7901、BGC-823、HGC-27、AGS及正常胃黏膜细胞系GES中表达情况。方法:免疫组织化学法检测HMGB1在32例可手术切除的胃癌患者组织标本(包括癌组织和正常组织)的表达情况;RT-PCR及Westren Blot检测HMGB1在胃癌细胞系SGC-7901、BGC-823、HGC-27、AGS及正常胃粘膜细胞系GES的m RNA及蛋白质表达。结果:胃癌组织HMGB1免疫组织化学染色评分高于正常组织(P0.05);RT-PCR结果显示SGC-7901、BGC-823、HGC-27、AGS、GES细胞系HMGB1 m RNA表达丰度均较高;Westren Blot检测发现胃癌细胞系SGC-7901、BGC-823、HGC-27中HMGB1蛋白水平显著高于胃癌细胞系AGS及正常胃粘膜细胞系GES。结论:HMGB1在胃癌组织及正常组织中的表达具有显著性差异。胃癌细胞系SGC-7901、BGC-823、HGC-27相对于其它胃细胞系存在HMGB1高表达,适合后续基因敲除分析工作。     

RNA干扰抑制Snail表达对于胃癌细胞上皮间充质转化以及体外侵袭的影响

目的用RNA干扰(RNAinterference,RNAi)技术抑制转录因子Snail表达,观察其对人胃腺癌SGC-7901细胞上皮-间充质转化表型和体外侵袭能力的影响。方法构建能表达针对Snail的小干扰RNA(Small interferingRNA,si RNA)的RNA干扰载体(Snail si RNAvector)和表达不针对任何已知mRNA的si RNA的阴性对照RNA干扰载体(control si RNAvector),分别转染SGC-7901细胞,筛选得到Snail表达受抑制的SGC-7901-siSnail细胞和Snail表达未受影响的SGC-7901-siControl细胞。分别采用RT-PCR和Western blot技术检测非转染组、SGC-7901-siSnail、SGC-7901-siControl三组细胞Snail、α-平滑肌肌动蛋白(α-SMA)和E-cadherin表达,用Boyden chamber模型检测细胞侵袭能力。结果 SGC-7901-siSnail组与SGC-7901-nontransfection组相比,Snail和α-SMA表达显著减弱(P0.01),E-cadherin表达显著增强(P0.01),Boyden chamber穿膜细胞数显著减少(P0.01);SGC-7901-siControl组中Snail、α-SMA、E-cadherin表达、Boyden chamber穿膜细胞数分别和SGC-7901-nontransfection组比较无显著差异(P0.05)。结论通过RNA干扰阻滞Snail表达能有效地抑制SGC-7901细胞上皮-间充质转化及体外侵袭能力。Snail可能在胃腺癌上皮-间充质转化及侵袭过程中扮演重要角色,抑制Snail表达可能成胃腺癌治疗的可行策略。     

敲低心肌连接斑株蛋白对人胃癌SGC-7901细胞的迁移和侵袭能力的影响及机制研究

该文研究了敲低心肌连接斑株蛋白(junction plakoglobin,JUP)对人胃癌SGC-7901细胞迁移和侵袭的影响及其机制。通过sh RNA慢病毒介导的方式构建了敲低JUP基因的慢病毒载体序列及其阴性对照病毒,并感染至人胃癌SGC-7901细胞中,荧光检测细胞感染效率,获得JUP基因稳定沉默及其对照细胞株。用嘌呤霉素筛选阳性转染细胞株,采用实时荧光定量PCR(q RT-PCR)和蛋白质免疫印记法(Western blot)检测JUP表达水平。采用细胞划痕愈合实验和Transwell小室实验检测敲低JUP基因之后对人胃癌SGC-7901细胞迁移和侵袭能力的影响。采用Western blot检测敲低JUP之后β-连环蛋白水平的影响。结果显示,通过sh RNA介导的慢病毒成功构建了敲低JUP基因的人胃癌SGC-7901稳定细胞株。与对照组相比,敲低JUP表达可促进细胞的迁移和侵袭能力(P0.05),上调了β-连环蛋白的水平(P0.05)。以上结果表明,敲低人胃癌SGC-7901细胞中JUP基因表达后可促进胃癌细胞SGC-7901的迁移和侵袭能力可能与其上调β-连环蛋白的水平从而活化Wnt信号通路有关。     

不同浓度姜黄素对胃癌SGC-7901细胞增殖、自噬性凋亡和TGF-β/Smad信号通路的影响

摘要 目的：研究不同浓度姜黄素（Cur）体外对胃癌SGC-7901细胞增殖、自噬性凋亡和TGF-β/Smad信号通路的影响。方法：体外培养SGC-7901细胞,以不同浓度Cur作用于SGC-7901细胞。MTT法检测不同浓度的Cur对SGC-7901细胞增殖的影响。Hoechst 33258法观察不同浓度Cur对SGC-7901细胞凋亡影响,流式细胞仪检测细胞凋亡率。划痕实验检测不同浓度Cur对SGC-7901迁移能力的影响。免疫印迹法检测细胞凋亡相关蛋白NF-κB、自噬相关蛋白Beclin1、LC3Ⅱ及TGF-β/Smad信号通路蛋白TGF-β和p-smad2/3表达。结果：Cur能够抑制胃癌SGC-7901细胞的增殖和迁移,并且Cur对增殖和迁移的影响具有浓度依赖性。Cur能够促进胃癌SGC-7901细胞自噬性凋亡的发生,Cur浓度越高,SGC-7901细胞凋亡率越高（P<0.05）。Cur处理胃癌SGC-7901细胞后NF-κB、Beclin1、LC3Ⅱ表达明显升高,而TGF-β、p-smad2/3表达明显降低,且NF-κB、Beclin1、LC3Ⅱ、TGF-β和p-smad2/3的变化具有浓度依赖性。结论：Cur能够抑制胃癌SGC-7901细胞增殖和迁移并诱导自噬性凋亡的发生,其机制与促进NF-κB、Beclin1、LC3Ⅱ表达,抑制TGF-β/Smad信号通路激活有关。     

幽门螺杆菌感染激活NF-κB信号通路促进胃癌SGC-7901细胞炎症因子释放

为了探讨幽门螺杆菌对胃癌SGC-7901细胞炎症因子释放的影响,本研究将幽门螺杆菌感染SGC-7901细胞后,采用细胞计数盒(CCK-8)检测SGC-7901细胞活力,酶联免疫吸附实验(ELISA)检测炎症因子TNF-α、IL-1β以及IL-8的水平,Real-time PCR检测细胞TNF-α、IL-1β以及IL-8 m RNA的表达,蛋白免疫印迹法(Western blotting)检测NF-κB信号通路相关蛋白NF-κB p65蛋白表达以及IκBα磷酸化水平。研究结果表明,幽门螺杆菌感染后,SGC-7901细胞活力显著增加;幽门螺杆菌感染明显上调SGC-7901细胞TNF-α、IL-1β以及IL-8 mRNA的表达;本研究还进一步发现幽门螺杆菌感染显著增加SGC-7901细胞TNF-α、IL-1β以及IL-8的水平;此外,幽门螺杆菌处理的SGC-7901细胞,其NF-κB p65的蛋白表达以及IκBα磷酸化水平均显著上调。本研究的结论初步表明,幽门螺杆菌感染促进胃癌SGC-7901细胞炎症因子的释放,其机制可能涉及激活NF-κB信号通路。     

全反式维甲酸诱导胃腺癌细胞周期阻滞的作用机制

目的:研究全反式维甲酸(all trans retinoic acid,ATRA)对人胃腺癌细胞(SGC-7901)细胞周期阻滞的诱导作用并探讨其机制.方法:采用四甲基偶氮唑盐(MTT)方法检测ATRA对SGC-7901增殖的抑制;流式细胞术检测细胞周期,Western blot方法检测不同浓度ATRA处理后的SGC-7901细胞中Akt、P-Akt(Ser473)、P-Akt(Thr308)、p-GSK-3β(Ser9)和cyclin D1的表达情况.结果:10.9～10.5mol/L的ATRA作用SGC-7901细胞48 h,能显著抑制细胞增殖,其抑制率分别为10.2%±0.5%、15.3%±0.5%、17.0%±0.7%、28.4%±1.0%和36.9%±0.7%;G1期细胞比率随着ATRA浓度的增加而增加,呈明显的G1期阻滞;Western blot检测显示ATRA对细胞中Akt蛋白的表达没有明显影响,两种p-Akt蛋白的表达显著下调,ATRA显著降低细胞中cyclin D1和p-GSK-3β的表达.结论:ATRA可能通过抑制磷酸化Akt蛋白表达而减少p-GSK-3β的表达,从而减少cyclin D1的表达量,进而诱导SGC-7901细胞发生G1期阻滞.     

华蟾素诱导人胃癌SGC-7901细胞凋亡

本实验旨在探讨华蟾素诱导人胃癌SGC-7901细胞凋亡的作用及其作用机制。采用不同浓度的华蟾素作用胃癌SGC-7901细胞48 h后,MTT法检测细胞活性;光学、荧光显微镜、流式细胞术检测细胞凋亡情况。Real Time RT-PCR和Western Blot分别检测Bax、Bcl-2基因m RNA和蛋白表达水平。结果显示,华蟾素对胃癌SGC-7901细胞增殖具有抑制作用且呈剂量依赖性关系,华蟾素处理7901细胞48 h的IC50值为35.67μg/m L,凋亡率为(5.01±1.69)%。显微镜下观察细胞呈明显凋亡现象,线粒体膜电位(ΔΨm)显著下降(p0.05),细胞阻滞于G1期;Bcl-2的表达下调,Bax的表达明显增加(p0.05,p0.01)。提示华蟾素可能通过上调Bax基因,下调Bcl-2基因诱导人胃癌SGC-7901细胞凋亡。     

Ad-IL-24对SGC-7901胃癌细胞生长抑制的体外实验

旨在研究携带人IL-24基因的腺病毒表达载体(Ad-IL-24)对SGC-7901人胃癌细胞的生长抑制作用并分析其分子机制。以不同MOI(感染复数)的Ad空载体腺病毒感染SGC-7901人胃癌细胞,筛选出最佳感染剂量;Ad-IL-24以最佳感染剂量感染SGC-7901胃癌细胞,RT-PCR法和Western blotting法检测腺病毒介导的IL-24基因在SGC-7901胃癌细胞中的转录;MTT法检测Ad-IL-24对SGC-7901胃癌细胞的生长抑制作用,流式细胞仪检测其诱导SGC-7901人胃癌细胞凋亡和细胞周期改变的效应,Hoechst33258染色荧光显微镜检测其诱导胃癌细胞凋亡的核形态改变;RT-PCR半定量法进一步检测SGC-7901胃癌细胞中凋亡相关基因的转录。结果显示,100MOI为感染SGC-7901胃癌细胞的腺病毒最佳感染剂量;Ad-IL-24能成功介导IL-24基因在SGC-7901胃癌细胞中转录性表达;Ad-IL-24感染SGC-7901胃癌细胞后,能明显抑制胃癌细胞生长和诱导凋亡;Ad-IL-24能显著上调SGC-7901胃癌细胞中bax、caspase-3和p53的表达和下调bc...     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.