带Myc、His标签的SPAG4L真核表达载体的构建与表达

为了获得带有His、Myc 双标签的SPAG4L蛋白,建立能够稳定表达该蛋白的细胞系,本研究利用PCR技术从人睾丸cDNA中扩增SPAG4L开放阅读框,构建到pcDNA3.1(+)myc-his真核表达载体中进行测序和双酶切验证。将pcDNA3.1/myc-His(-)A/SPAG4L质粒和空白载体分别转染HeLa细胞,G418筛选后建立稳定转染细胞系。用Western blotting和免疫荧光技术对新建立的稳定转染细胞系进行检测。结果表明,成功扩增了SPAG4L基因,构建到pcDNA3.1/myc-His(-)A真核表达载体后,经酶切和测序验证所插入的SPAG4L序列完全正确;pcDNA3.1/myc-His(-)A/SPAG4L转染HeLa细胞后,经G418筛选后建立了稳定转染细胞系。Western blotting检测后发现,新建立的细胞系能够正确表达SPAG4L及其标签蛋白,进一步的免疫荧光实验发现,SPAG4L能够和内质网标签蛋白PDI共定位。研究结果所提供的稳定转染细胞系将为下一步进行免疫共沉淀和pull-down实验提供了有力的工具。     

中国人促红细胞生成素cDNA的克隆及其在COS—7细胞中的表达

利用PCR技术,以中国人促红细胞生成素(EPO)次全基因组为模板,进行了基因修补和重组,克隆出EPO cDNA全序列。同时发现中国人EPO cDNA与国外的克隆比较有一个核苷酸的差异,导致第62位氨基酸是丝氨酸,不是亮氨酸。将人EPO cDNA基因插入表达载体pSV2-dhfr中的不同克隆位点,构建了6种不同的转移载体质粒,即pSV2-dhfr/F1,pSV2/N2,pSV2-dhfr/F3,pSV2-dhfr/P4,pSV2-dhfr/G1和pSV2-dhfr/G3。将它们分别转染导入COS-7细胞,结果表明6种转移载体质粒转染的细胞上清液都有明显的EPO活性。人EPO cDNA基因转移载体质粒在COS-7细胞中的表达水平高于人次全EPO基因组转移载体质粒。     

中国人促红细胞生成素cDNA的克隆及其在COS-7细胞中的表达

利用PCR技术。以中国人促红细胞生成素(EPO)次全基因组为模板,进行了基因修补和重组．克隆出EPO cDNA全序列。同时发现中国人EPO cDNA与国外的克隆比较有一个核苷酸的差异,导致第62位氨基酸是丝氨酸．不是亮氨酸。将人EPO cDNA基因插入表达载体pSV2-dhfr中的不同克隆位点,构建了6种不同的转移载体质粒,即psV2 dhfr／F1,pSV2／F2,pSV2 dbfT／F3,pSV2 dhfr／F4,pSV2-dhfr／G1和psV2 dhfr／G3。将它们分别转染导人COS-7细胞,结果表明6种转移载体质粒转染的细胞上清液都有明显的EPO活性。人EPO cDNA基因转移载体质粒在COS-7细胞中的表达水平高于人次全EPO基因组转移载体质粒。     

一个在肺腺癌细胞系中差异表达cDNA片段的定位及表达分析

为了研究和克隆肺癌转移相关候选基因,探讨肺癌发生及转移的分子基础,应用细胞培养,cDNA克隆,Noorthern印记杂交和生物信息学技术分析了在细胞来源相同,但转移能力不同的肺腺癌细胞系AGZY83－a和Anip973中差异表达片段OPB7－1在人不同组织中和不同人肺癌细胞系中的表达情况,并应用RH定位技术对该片段进行了基因定位。表明OPB7－1与已知基因同源性差,该基因在正常人多种组织中有表达,心肌和骨骼肌中高表达,转录本均为3.0kb左右。在不同人肺癌细胞系中存在该基因的表达差异,高转移潜能,低分化及高浸润的细胞系中呈高表达趋势,且表达的片段大小略有差别。提示OPB7－1是一个具有广泛表达为的基因,可能是与肺癌的发生发展相关的新基因。     

一株棕尾别麻蝇胚胎细胞系的建立及其特性分析

双翅目昆虫细胞系广泛应用于遗传学、发育生物学、分子生物学、人和动物体病原学以及昆虫抗微生物肽的研究。本研究建立了一株新的棕尾别麻蝇Sarcophaga peregrina胚胎细胞系。该细胞系的原代培养始于2008年11月17日, 取材于棕尾别麻蝇晚期胚胎组织, 在Shields & Sang M3昆虫培养基中于28℃恒温培养, 在第26天进行第1次传代, 至今已历时21个月, 传代72次, 生长状态稳定, 被命名为Sp-E-HNU11。该细胞系的细胞形态主要呈梭形和近圆形, 杂以少量巨型细胞, 紧密贴壁生长。细胞群体倍增时间为42 h。染色体数目一般为10条或12条, 为二倍体或亚二倍体细胞系; 除一对颗粒状微型染色体外, 其他染色体呈短杆状。细胞系的β-萘酯酶和谷草转氨酶同工酶谱上分别显示出1条和3条酶带。随机引物扩增多态性 (random amplified polymorphic DNA, RAPD) 分析结果显示, 该细胞系与小菜蛾细胞系Px-E-HNU12、草地贪夜蛾细胞系IPLB-Sf-9和家蚕细胞系Bm-21E-HNU5呈现明显不同的带型特征。 Sp-E-HNU11细胞系的建立为昆虫抗微生物肽及其他相关的研究工作增添了新的研究工具和生产载体。     

美国生化公司生产的cDNA ClonStruct盒

设计了一种能促进全长cDNA有效克隆的cDNA ClonStruct盒。完整盒包括载体引物、所有必需酶及试剂,从而构建五个cDNA库。单个库构建需要10～20μg poly A~+ RNA。大型的、具有高度代表性的cDNA库构建方法是: 用一改良载体作首链合成引物。通过末端脱氧核苷酸转移酶(TdT)加入C尾部序列以修饰载体-cDNA:mRNA杂种分子的每一端。仔细校正反应条件使其正如参入5～20个残基的尾部序列。载体含     

食管癌细胞抗失巢凋亡基因UBCH7的发现与鉴定

失巢凋亡(Anoikis)是细胞失去与细胞外基质(Extra-cellular matrix, ECM)粘附时发生的特殊形式的凋亡, 是机体维持组织稳态的关键机制之一。抗失巢凋亡能力的获得是肿瘤细胞发生远处转移的前提条件之一。为了鉴定与食管癌细胞抗失巢凋亡相关的基因, 文章首先构建食管癌细胞系的逆转录病毒文库, 感染对失巢凋亡敏感的NIH3T3细胞, 利用感染病毒cDNA文库的混合细胞系进行软琼脂集落形成实验, 挑取在悬浮条件下仍可生长成为较大集落的细胞单克隆(潜在具有抗失巢凋亡能力的细胞), 通过逆转录病毒载体特异的引物PCR扩增失巢凋亡抗性克隆基因组中的插入cDNA片段, 以此获得食管癌细胞系cDNA文库中潜在的具有失巢凋亡抗性的基因。经测序发现其中一个失巢凋亡克隆中整合的cDNA片段包括人UBCH7/UBE2L3基因全长的编码序列(开放阅读框)。利用携带pMSCV-UBCH7的逆转录病毒感染NIH3T3细胞进行验证, 结果显示细胞失巢凋亡抗性增强, 并且在具有高转移潜能的食管癌细胞系MLuC1中降调UBCH7表达可减弱其失巢凋亡抗性。这些结果表明, UBCH7/UBE2L3是一个与食管癌失巢凋亡抗性相关的基因。     

食管癌细胞抗失巢凋亡基因UBCH7的发现与鉴定

失巢凋亡(Anoikis)是细胞失去与细胞外基质(Extra-cellular matrix,ECM)粘附时发生的特殊形式的凋亡,是机体维持组织稳态的关键机制之一。抗失巢凋亡能力的获得是肿瘤细胞发生远处转移的前提条件之一。为了鉴定与食管癌细胞抗失巢凋亡相关的基因,文章首先构建食管癌细胞系的逆转录病毒文库,感染对失巢凋亡敏感的NIH3T3细胞,利用感染病毒cDNA文库的混合细胞系进行软琼脂集落形成实验,挑取在悬浮条件下仍可生长成为较大集落的细胞单克隆(潜在具有抗失巢凋亡能力的细胞),通过逆转录病毒载体特异的引物PCR扩增失巢凋亡抗性克隆基因组中的插入cDNA片段,以此获得食管癌细胞系cDNA文库中潜在的具有失巢凋亡抗性的基因。经测序发现其中一个失巢凋亡克隆中整合的cDNA片段包括人UBCH7/UBE2L3基因全长的编码序列(开放阅读框)。利用携带pMSCV-UBCH7的逆转录病毒感染NIH3T3细胞进行验证,结果显示细胞失巢凋亡抗性增强,并且在具有高转移潜能的食管癌细胞系MLuC1中降调UBCH7表达可减弱其失巢凋亡抗性。这些结果表明,UBCH7/UBE2L3是一个与食管癌失巢凋亡抗性相关的基因。     

EphA3促进胃癌细胞BGC823的增殖

目的:初步探索EphA3与胃癌细胞BGC823增殖的关系。方法:用T_4DNA连接酶将EphA3的全长cDNA片段连接到酶切后的慢病毒载体pCDH-EF1-MCS-T2A-Puro中制备慢病毒,感染胃癌BGC823细胞建立过表达EphA3细胞系,Western印迹检测目的蛋白的表达,CCK8细胞生长实验和裸鼠成瘤实验检测EphA3对BGC823细胞增殖的影响。结果:双酶切鉴定与基因测序表明过表达EphA3慢病毒载体构建成功;Western印迹表明建立了过表达EphA3的BGC823细胞系,高表达EphA3对BGC823细胞的增殖和成瘤后生长有明显的促进作用。结论:EphA3促进BGC823胃癌细胞增殖,为胃癌的靶向性治疗及个性化治疗提供了线索。     

应用cDNA微阵列技术研究EB病毒LMP1介导的鼻咽癌中转移相关基因的表达

探讨EB病毒基因组编码的癌蛋白LMP1对鼻咽癌细胞中转移相关基因表达的影响.采用蛋白质印迹法检测在强力霉素(Dox)诱导下,鼻咽癌细胞系pTet-on-LMP1 HNE2(L7细胞)中LMP1表达的时效和量效关系.应用cDNA微阵列技术建立诱导性LMP1介导鼻咽癌细胞中转移相关基因差异表达谱;运用RT-PCR验证cDNA微阵列筛选差异基因表达的可靠性.与LMP1不表达的L7细胞比较,LMP1高表达的L7细胞中7个基因的表达显著上调,12个基因的表达显著下调.随机选择其中4个基因进行RT-PCR,结果显示,这些基因表达阳性,且与微阵列中的变化趋势一致.LMP1可能通过激活和/或抑制一些转移相关基因的表达而参与鼻咽癌转移过程.     

Identification of differentially expressed genes in isogenic highly metastatic and poorly metastatic cell lines of R3230AC rat mammary adenocarcinoma

Tumour metastasis occurs as a result of a cascade of events including alterations in the expression of various genes. The identification of such genes is essential to understanding formation of metastasis. In a previous study, highly metastatic (LN4.D6) and poorly metastatic (CAb.D5) cell lines were obtained from the rat mammary adenocarcinoma cell line R3230AC. Subtractive hybridization was used to identify differentially expressed genes between these two cell lines. We identified eight cDNA clones in CAb.D5 and six cDNA clones in LN4.D6 that were differentially expressed. One of the cDNA clones in each cell line had no homology with known sequences. Expression patterns of these differentially expressed genes were examined in a pair of rat mammary and prostate adenocarcinoma cell lines. Compared with cell lines examined, cDNA FF-10 was only expressed in CAb.D5; however, cDNA RB-8, RE-1, RF-5 were only expressed in the highly metastatic LN4.D6. No correlation was observed between expression patterns of the differentially expressed genes and metastatic potential of these cells. However, differential expression of genes, especially cytokeratins (CK8 and CK5) and collagens (III and IV) between highly metastatic and low metastatic rat mammary adenocarcinoma cell lines might initiate further investigation of these genes in metastatic process.     

鼻咽癌转移相关基因的比较基因组杂交和cDNA微阵列研究

为筛选在鼻咽癌转移中起重要作用的基因 ,应用比较基因组杂交 (CGH)和cDNA微阵列方法研究成瘤和转移能力不同的鼻咽癌细胞株 6 10B和 5 8F .CGH结果显示 ,2种细胞株在 5p、7q、8p、9q、11p、12q和 17p的一定区域存在差异性扩增 ,在 2q存在差异性缺失 ;cDNA微阵列显示 ,相对于非转移性 6 10B细胞株 ,高转移性 5 8F细胞表现一些基因表达的上调及下调 ,CGH和cDNA微阵列的结合是筛选转移相关基因较好方法     

用基因芯片结合荧光差异显示—PCR筛选和识别胃腺癌转移相关的基因

使用来源于同一个胃腺癌病人的原发灶RF－1（ATCC编号：CRL－1864）和转移灶RF－48细胞系（ATCC编号,CRL－1863）作为研究肿瘤转移分子机制的模型,RF－1（实验组）和RF－48（对照组）的mRNA通过逆转录方法,将Cy3和Cy5两种荧光染料分别标记到两种细胞的cDNA上,制备成cDNA探针,并与表达谱芯片（双点4096条基因）进行杂交与扫描,重复2次实验,利用计算机数据处理判断基因是否在上述两种细胞中有表达差异,共筛选出差异表达的基因共138条,其中81条在RF－48细胞中表达明显上调,57条在RF－48细胞中表达显著下调,同时也通过荧光差异显示－PCR（FDD－PCR）技术,克服了45个涉及胃腺癌转移相关基因,包括未被发现的基因3个,在两种筛选方法中都存在差异表达的基因共有7条,对部分可能与肿瘤志移机制有关的差异表达基因的作用进行了分析和讨论,基因芯片技术可高通量,大规模地研究基因表达水平,FDD－PCR技术可克隆出未发现的新基因,二者结合,初步筛选出与转移相关的基因,有助于揭示胃腺癌转移的分子机制。     

cDNA transfection of amino-terminal fragment of urokinase efficiently inhibits cancer cell invasion and metastasis.

Focusing of urokinase-type plasminogen activator (uPA) to the cell surface via binding to its specific receptor (uPAR, CD87) is critical for tumor invasion and metastasis. Consequently, the inhibition of uPA-uPAR interaction on the cell surface might be a promising anti-invasion and anti-metastasis strategy. We examined the effects of cDNA transfection of the human uPA amino-terminal fragment (ATF) on invasion and metastasis of cancer cells. First, a highly metastatic human lung giant-cell carcinoma cell line (PG), used as the target cell for evaluation of this effect, was demonstrated to express both uPA and uPAR. Then, ATF, which contains an intact uPAR binding site but is catalytically inactive, was designed as an antagonist of uPA-uPAR interaction and was transfected into PG cells. [(3)H]-Thymidine incorporation and cell growth curves indicated that expressed ATF did not affect the proliferation of transfected cells. However, analysis by scanning electron microscopy revealed that ATF changed the host cells from the typical invasive phenotype to a noninvasive one. Correspondingly, the modified Boyden chamber test in vitro showed that ATF expression significantly decreased the invasive capacity of transfected cells. Furthermore, in the spontaneous metastasis model, it was confirmed in vivo that expressed ATF remarkably inhibited lung metastasis of implanted ATF-transfected PG cells. In summary, autocrine ATF could act as an antagonist of uPA-uPAR interaction, and ATF cDNA transfection could efficiently inhibit the invasion and metastasis of the cancer cells. Inhibition of uPA-uPAR interaction on the cell surface might be a promising anti-invasion and anti-metastasis strategy.     

Inhibition of metastasis to lung of a human nasopharyngeal carcinoma cell line CNE-2L2 transfected with pRc/CMV-antisense 6A8 cDNA in nude mice

The growth of CNE-2L2 cell, a cloned line of human nasopharyngeal carcinoma with a high potentiality of metastasis to lung was inhibited to a certain extent after transfection with a recombinant antisense expression vector of a cDNA encoding a human α-mannosidase (pRc/CMV-antisense 6A8 cDNA)( the Genbank accession number of 6A8 cDNA is U37248) in comparison with that of the cell transfected with the Mock and of the wild cell. Two months after a subcutaneous inoculation of CNE-2L2 cell into the axilla of nude mice metastatic lesions in the lung were observed in 9/10 mice (90%) with grade Ⅲ in 8 mice and grade Ⅱ in one mouse in the wild cell group, in 6/8 mice (75%) with grade Ⅲ in one mouse, grade Ⅱ in 2 mice and grade Ⅰ in 3 mice in the Mock-transfection group, in only 3/10 mice (30%) with all grade Ⅰ in pRc/CMV-antisense 6A8 cDNA-transfection group.     

Inhibition of metastasis to lung of a human nasopharyngeal carcinoma cell line CNE- 2L2 transfected with pRc/ CMV-antisense 6A8 cDNA in nude mice

The growth of CNE-2L2 cell, a cloned line of human nasopharyngeal carcinoma with a high potentiality of metastasis to lung was inhibited to a certain extent after transfection with a recombinant antisense expression vector of a cDNA encoding a human α-mannosidase (pRc/CMV-antisense 6A8 cDNA) (the Genbank accession number of 6A8 cDNA is U37248) in comparison with that of the cell transfected with the Mock and of the wild cell. Two months after a subcutaneous inoculation of CNE-2L2 cell into the axilla of nude mice metastatic lesions in the lung were observed in 9/10 mice (90%) with grade III in 8 mice and grade II in one mouse in the wild cell group, in 6/8 mice (75 %) with grade III in one mouse, grade II in 2 mice and grade I in 3 mice in the Mock-transfection group, in only 3/10 mice (30%) with all grade I in pRc/CMV-antisense 6A8 cDNA-transfection group.     

TM7XN1, a novel human EGF-TM7-like cDNA, detected with mRNA differential display using human melanoma cell lines with different metastatic potential

We have identified a novel 3845 bp cDNA differentially expressed in a human melanoma metastasis model. Northern blot analysis showed expression in the poorly and intermediately metastasizing cell lines and a marked downregulation in the highly metastatic cell lines. Using RT-PCR expression was also seen in several other tumor cell lines and normal cell types of human origin. cDNA sequence analysis revealed an ORF of 687 amino acids containing seven putative transmembrane domains C-terminally and a long N-terminus. The gene was mapped to 16q13. Highest homology was observed with members of the EGF-TM7 subfamily of the secretin/calcitonin receptor family. We propose the delineation of a subfamily of TM7 proteins, LN-TM7, containing seven transmembrane proteins with a long N-terminal extracellular part.     

利用GenMAPP筛查鼻咽癌差异表达基因

利用GenMAPP软件对鼻咽癌和正常鼻咽上皮基因微阵列表达谱结果进行分析,筛查鼻咽癌差异表达基因. 结果显示：在17 000个基因中,与正常鼻咽上皮相比,在鼻咽癌中发生2倍以上差异表达的基因共有339个,其中有160个基因在鼻咽癌中表达上调,179个表达下调. 这些基因分别与细胞增殖、基因转录、凋亡、信号转导、DNA损伤修复、肿瘤分化和浸润转移及细胞周期调节等相关. 鼻咽癌的发生发展存在多基因表达调控的改变,对其差异表达基因的研究有助于阐明鼻咽癌发生发展机制.     

Mammalian heparanase: gene cloning, expression and function in tumor progression and metastasis.

Heparan sulfate proteoglycans interact with many extracellular matrix constituents, growth factors and enzymes. Degradation of heparan sulfate by endoglycosidic heparanase cleavage affects a variety of biological processes. We have purified a 50-kDa heparanase from human hepatoma and placenta, and now report cloning of the cDNA and gene encoding this enzyme. Expression of the cloned cDNA in insect and mammalian cells yielded 65-kDa and 50-kDa recombinant heparanase proteins. The 50-kDa enzyme represents an N-terminally processed enzyme, at least 100-fold more active than the 65-kDa form. The heparanase mRNA and protein are preferentially expressed in metastatic cell lines and specimens of human breast, colon and liver carcinomas. Low metastatic murine T-lymphoma and melanoma cells transfected with the heparanase cDNA acquired a highly metastatic phenotype in vivo, reflected by a massive liver and lung colonization. This represents the first cloned mammalian heparanase, to our knowledge, and provides direct evidence for its role in tumor metastasis. Cloning of the heparanase gene enables the development of specific molecular probes for early detection and treatment of cancer metastasis and autoimmune disorders.