鼠源抗AFB1噬菌体单链抗体库的构建与鉴定

研究以AFB1-BSA免疫的小鼠脾脏细胞为试验材料,利用RT-PCR技术,克隆了抗AFB1抗体重链和轻链可变区基因VH和VL,利用连接肽(Gly4Ser)3将VH和VL链接成单链抗体基因scFv,通过噬菌体展示载体pCANTAB-5E携带将其电转化E.coli TG1,经氨苄青霉素平板筛选,构建了库容为2.13×109 cfu/μg DNA的噬菌体单链抗体库,抗体库的克隆阳性率达到100%,且多样性良好,为高活性抗AFB1单链抗体的筛选提供了材料基础。     

EL-4荷瘤鼠单链噬菌体抗体库的构建

目的:构建一个EL-4荷瘤鼠的单链噬菌体抗体库,为筛选高特异性和高亲和力的单链抗体做准备.方法:于C57小鼠腋区接种EL-4细胞,待肿瘤长大后,从脾细胞中提取总RNA,RT-PCR技术扩增小鼠抗体重、轻链可变区基因(VH、VL),用Linker奖VH和VL基因连成单链抗体可变区片段(scFv).双酶切后(Not Ⅰ、Sfi Ⅰ)与预备好的pCANTAB5E噬粒载体连接,转化入感受态TG1,构建EL-4荷瘤鼠的单链噬茵体抗体库.随机抽取转化后的20个克隆,用以检测外源DNA的转入情况.结果:PCR扩增出的VH约有340bp和VL约有320bp,scFv的长度约有750bp.转化后的TG1约有1.67×107个茵落,随机挑取20个克隆,双酶切显示五分之一的茵落转化了外源DNA片段,有效库容为3.34×106.结论:成功构建了EL-4荷瘤鼠的单链噬茵体抗体库.     

抗弓形虫噬菌体单链抗体库的构建及筛选

采用弓形虫可溶性抗原攻击的小鼠,取小鼠脾脏从中提取细胞总RNA,通过RT-PCR扩增鼠源抗体VH和VL基因,并采用重叠PCR (SOE-PCR)方法构建ScFv基因,将其克隆入噬粒载体pCANTAB5E中,转化于感受态大肠杆菌TG1,通过辅助噬菌体M13K07援救构建噬菌体单链抗体库.从20个噬菌体克隆中筛选到15个具...     

抗PAF单链抗体的基因构建及蛋白质3D模建

构建抗PAF单链抗体的基因并通过计算机模建分析几种不同连接类型的单链抗体空间结构差异。采用重叠延伸PCR方法扩增了VH和VL基因,形成抗PAF的VH-Linker-VL(ScFv)基因产物,并经菌落PCR和测序分析鉴定,通过Internet对其3D结构进行了模建与分析,研究结果表明：PCR产物电泳可见一条与目的基因大小一致的片段,经菌落PCR和测序分析鉴定,抗PAF单链抗体的基因构建成功;VH和VL在单链抗体中的顺序对单链抗体3D的空间结构有影响。     

抗克伦特罗噬菌体单链抗体库的构建、筛选及鉴定

利用噬菌体展示技术构建克伦特罗(CBL)单链抗体(scFv)库,从中筛选CBL特异性噬菌体scFv,从而成功扩增出抗CBL的VL,VH基因片段并采用重叠延伸PCR拼接为全长的scFv基因片段,抗体库库容约为1.6×104,经4轮吸附—洗脱—扩增的富集,采用酶联免疫吸附测定(ELISA)法筛选到6个具有CBL结合活性的噬菌体scFv,为进一步大量表达CBL单链抗体奠定了基础.     

一种噬菌体质粒的构建及其在抗体库模型筛选中的应用

目的 噬菌体展示技术(Phage display technology, PDT)是一种独立于任何免疫系统并在体外进行筛选多肽或者抗体的一种技术,可以从噬菌体抗体库中筛选得到特异性结合的单克隆抗体(monoclonal antibody)。本研究提出了一种应用于噬菌体抗体库筛选的质粒构建方法,旨在提高噬菌体展示技术的筛选效率。方法 首先将编码整个抗体结合域的基因(以单链可变片段scFv的形式)融合到基因III,并在融合噬菌粒scFv-PIII间引入牛凝血酶(thrombin)酶切位点,通过SDS-PAGE及Western Blot实验验证牛凝血酶特异性洗脱效果,同时利用ELISA(酶联免疫吸附实验)及噬菌体滴度检测特异性洗脱后单链抗体的结合活性,最后根据该质粒设计一种新的模型筛选方法,验证筛选效率。结果 本研究成功构建目标质粒并利用该质粒进行模型筛选,证实筛选效率得到提高。结论 在构建噬菌体抗体库的噬菌粒载体上添加牛凝血酶特异性酶切位点的筛选方法,可以减少筛选轮次高效筛选出特异性噬菌体抗体。     

人源性抗HBc单链噬菌体抗体库的构建

利用RT－PCR和噬菌体表面展示技术，直接从乙肝病毒核心抗体（抗HBc）阳性患淋巴细胞中提取总RNA，反转录成cDNA；合成全套人抗体可变区引物扩增抗体可变区基因，并将重、轻链可变区基因进行拼接装配成单链抗体（ScFv）基因，重组于噬菌粒载体pHEN1，转化抑制型大肠杆菌E.coliTG1，以辅助噬菌体援救后，构建成人源性单链噬菌体库。库容量达106。     

nm23-H1基因对乳腺癌细胞MCF-7S增殖及移动特性的影响

目的：探讨nm23—H1基因转染乳腺癌细胞后对其增殖和转移能力的影响。方法：用人nm23—H1基因与真核表达质粒pcDNA3．1(—)构建成重组表达质粒pcDNA3．1—NMHl，转染人乳腺癌细胞MCF—7S，经G418筛选4周后，筛选出稳定表达nm23—H1的细胞株，绘制其生长曲线，检测其增殖、移动能力，用SPSS统计软件处理实验数据，分析nm23—H1基因对乳腺癌细胞的作用。结果：与对照组相比，转染nm23—H1基因的MCF—7S细胞的对数生长期延长，细胞增殖速度减慢，移动距离缩短，克隆形成率降低。结论：nm23—H1基因在乳腺癌细胞的体外实验中有抑制癌细胞生长、增殖、转移能力的作用。     

抗HBsAg单链Fab抗体基因酵母表达载体的构建

采用重叠PCR技术 ,以抗乙肝表面抗原 (HBsAg)IgG铰链区基因为Linker将Fab抗体基因的重链和轻链连接起来 ,构成单链Fab基因。通过测序鉴定 ,克隆的单链Fab基因与理论上的完全一致 ,并成功构建含完整单链Fab基因的毕赤酵母 (P pastoris)表达载体。     

人源抗HBsAg单链抗体与干扰素嵌合基因的构建及表达

采用重叠PCR技术，将人源性抗HBsAg单链抗体基因与干扰素γ基因用柔性肽段碱基连接成单一基因。序列测定结果表明，克隆的基因与理论上的一致，并将此基因成功构建到酵母表达载体pPICZa上，进而转化到巴斯德毕赤酵母(Pichia Pastoris)X33中。筛选出的菌落经甲醇诱导培养，对上清液进行SDS—PAGE和WESTERN BLOT分析，在42000处可见蛋白表达带，这为进一步纯化目的蛋白和提高目的蛋白表达水平奠定了基础。     

A novel peptide,selected from phage display library of random peptides,can efficiently target into human breast cancer cell

To develop a targeting vector for breast cancer biotherapy, MDA-MB-231 cell, a human breast cancer cell line, was co-cultured with pC89 （9 aa） phage display library of random peptides. In multiple inde-pendent peptide-presenting phage screening trials, subtilisin was used as a protease to inactivate extra-cellular phages. The internalized phages were collected by cell lysising and amplified in E. coli XLI-Blue. Through five rounds of selection, the pepUde-presenting phages which could be internalized in MDA-MB-231 cells were isolated. A comparison was made between internalization capacities of peptide-presenting phages isolated from MDA-MB-231 cells and RGD-integrin binding phage by coculturing them with other human tumor cell lines and normal cells. The nucleoUde sequences of isolated peptide-presenting phages were then determined by DNA sequencing. To uncover whether phage coat protein or amino acid order was required for the character of the pepUde to MDA-MB-231 cells, three peptides were synthesized. They are CASPSGALRSC, ASPSGALRS and CGVIFDHSVPC （the shifted sequence of CASPSGALRSC）, and after coculturing them with different cell lines, their targeting capacities to MDA-MB-231 cells were detected. These data suggested that the internalization process was highly selective, and capable of capturing a specific peptide from parent peptide variants. Moreover, the targeting internalization event of pepUdes was an amino acid sequence dependent manner. The results demonstrated the feasibility of using phage display library of random peptides to develop new targeting system for intracellular delivery of macromolecules, and the peptide we obtained might be modified as a targeting vector for breast cancer gene therapy.     

腺病毒介导MTS1的抑癌作用

人多肿瘤抑制因子（MTS1）是一个抑瘤基因,在许多原发性肿瘤及细胞系中都发现了它的突变,有潜在应用价值。由于腺病毒独特的性质,它介导的肿瘤基因置换疗法,受到了愈来愈多的应用与关注。人癌胚抗原启动子能指导组织特异性表达。将癌胚抗原启动子置于MTS1基因上游,并在下游加poly A化信号,通过穿梭质粒pΔE1SP1A在人胚肾细胞HEK 293中与腺病毒载体pBHG11进行同源重组,插入腺病毒E1区。获得的重组病毒粒子作用于人乳腺癌细胞系MCF7,初步表明重组腺病毒能抑制MCF7的生长。     

Study on interleukin-18 gene transfer into human breast cancer cells to prevent tumorigenicity

To study the effect of interleukin-18 gene transfection on the tumorigenesis of breast cancer cell line Bacp37, human breast cancer cell line Bcap37 were transfected with Lipofectamine and selected by G418. The biological expression of rhIL-18 was tested by RT-PCR and ELISA method; nude mice were injected with Bcap37 cell with or without the hIL-18 gene. The hIL-18 cDNA was successfully integrated into Bcap37 cell; 126.3+/-4.5 pg hIL-18 secreted by one million transduced cells in 24 hours. Nude mice injected with IL-18 gene engineered Bcap37 cell had no tumor growth. These findings indicated that human breast cancer cells were successfully modified by the gene of IL-18 cytokine; the IL-18 gene engineered Bcap37 cells secreted hIL-18 and lost their tumorigenicity. The Bcap37 cells transduced with IL-18 gene may be used as breast cancer vaccine.     

Cloning of aminopeptidase N promoter and its activity in hematopoietic cell and different tumor cell lines

Aminopeptidase N (APN) promoter region was cloned and sequenced from peripheral blood mononuclear cells. The recombinant reporter construct containing the promoter and luciferase gene, designated pXP1-APNLuc, was introduced into myeloblastic cell line, T lymphocyte cell line and various tumor cell lines. Luciferase assay showed that APN upstream promoter is myeloid-specific for high expression in myeloblastic cell line and much lower expression in T lymphocyte cell line. The promoter activity was relatively high in lung adenoma cell line compared with other tumor cell lines including hepatoma cell line, tong cancer cell line and esophageal cancer cell line in which the promoter activity significantly diminished or was almost undetectable. The characteristics of APN promoter may provide a new strategy for specific myeloprotection while tumor patients are being treated with chemotherapy and/or radiotherapy.     

粘细菌代谢产物对乳腺癌细胞抗性的作用

粘细菌是一类具有丰富代谢产物的药源微生物,有潜在的新药开发价值。乳腺癌是多发于女性的一种恶性肿瘤,目前尚不能较好的控制,使用具有新作用机理的新型药物治疗可能提供其良好的解决方案。本研究对内蒙古鄂尔多斯地区土壤样品中分离到的七株粘细菌进行鉴定并对其代谢产物进行抗人乳腺癌MCF-7细胞检测,为研发高效安全的新型抗肿瘤活性物质奠定基础。采用兔粪诱导法、大肠杆菌划线法、大肠杆菌点种法、纤维素诱导法对采集的土样进行粘细菌的分离,通过形态学结合分子生物学手段鉴定纯化的粘细菌菌株。采用CCK-8法对粘细菌产生的代谢产物进行MCF-7细胞毒性检测,并对其抗肿瘤活性进行评价。经鉴定,E44属珊瑚球菌属珊瑚状珊瑚球菌（Corallococcus coralloides）,E603、E1201、E1202为粘球菌属变绿粘球菌（Myxococcus virescens）,E701、E703、E705为粘球菌属橙色粘球菌（Myxococcus fulvus）,其代谢产物均对人乳腺癌MCF-7细胞株具有抑制作用,最高肿瘤细胞抑制率在70.45%-106.29%之间,其中Myxococcus fulvus E701代谢产物对肿瘤细胞的抑制效果最强。本次实验分离的七株粘细菌菌株对人乳腺癌MCF-7细胞株均有明显的抑制效果,该研究为今后菌株活性物质的分离鉴定及作用机理研究奠定了基础。     

山奈酚诱导三阴性乳腺癌细胞MDA-MB-231中乳腺癌耐药蛋白的表达并下调抗肿瘤药物对MDA-MB-231细胞的杀伤作用

为确定三叶青活性物质山奈酚对三阴性乳腺癌(triple negative breast cancer,TNBC)的影响及其作用的分子机制,通过定量PCR的方法检测TNBC临床标本及MDA-MB-231细胞中孕烷X受体(pregnane X receptor,PXR)的表达情况;通过荧光素酶报告基因活性检测确定山奈酚对MDA-MB-231细胞中PXR转录因子活性的影响;通过MTT(四唑盐)方法、裸鼠皮下成瘤方法研究了山奈酚以及抗肿瘤药物卡铂、维利帕尼以及拉帕替尼等对MDA-MB-231细胞的抗肿瘤作用。结果表明:PXR在TNBC临床标本以及MDA-MB-231细胞中有明确表达;山奈酚能够诱导MDA-MB-231细胞对抗肿瘤药物卡铂、维利帕尼以及拉帕替尼等对MDA-MB-231细胞的杀伤作用;山奈酚能够诱导MDA-MB-231中PXR的转录因子活性以及PXR下游基因乳腺癌的表达;使用小干扰RNA(small interfere RNA,siRNA)抑制乳腺癌耐药蛋白(breast cancer resistance protein,BCRP)的表达能够逆转山奈酚诱导的抗肿瘤药物耐药。可见,山奈酚诱导TNBC细胞MDA-MB-231中乳腺癌耐药蛋白的表达并下调抗肿瘤药物对MDA-MB-231细胞的杀伤作用。     

Fractalkine基因真核表达质粒的构建及其在小鼠肝癌细胞中的表达

为克隆小鼠趋化因子Fractalkine(．FK)基因，构建真核表达质粒，并在小鼠肝癌细胞中表达，用以进行肿瘤的基因治疗，用RT-PCR法，从小鼠乳腺癌细胞D2F2扩增FK的cDNA，插入pCR2．1 TOPO载体，测序证实后，将其亚克隆至质粒pIRES中构建FK真核表达载体；用脂质体将重组质粒转染小鼠肝癌MM45 T．Li细胞，经G418筛选获得抗性细胞克隆，用RT-PCR和免疫化学方法鉴定转染细胞中FK基因的表达．结果表明：经限制性内切酶酶切图谱分析和DNA序列测定证实目的基因已插入重组质粒，RT-PCR和免疫化学方法证明转基因MM45T．Li细胞克隆中存在小鼠FK基因的表达。     

一种具有抗肿瘤活性的新型尿激酶原Kringle结构域变体蛋白的研究

利用PCR技术获得人尿激酶原Kringle结构域基因,将其克隆至具有T7启动子的表达质粒pET29a中,并进而插入plasminogen Kringle 5一段16肽片段构建了其变体,重组质粒转化至大肠杆菌BL21中,经IPTG诱导表达,其产物以包涵体形式存在．通过体外复性,得到可溶性的prourokinase Kringle及其变体．所得蛋白质经过动物肿瘤模型测活,确定变体蛋白具有抑制肿瘤生长作用．     

Recombinant sTRAIL induces cell death of tumor cell lines as well as primary cancer cells

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a new member of TNF family. It was reported that TRAIL could induce apoptosis of tumor cells but not normal cells in tissue culture system. To further study the biological activity and potential clinical significance, a recombinant soluble TRAIL (rsTRAIL) has been expressed stably in E. coli after transformation of pET28b vector containing the extracellular domain of TRAIL. The yield of rsTRAIL is approximately as high as 60% of whole bacterial proteins. The rsTRAIL, purified by Ni+ -agarose affinity chromatography, could remarkably trigger apoptosis at the concentrations of 0.1-1 μg/mL in all 7 tumor cell lines tested in vitro. However, this killing activity has not been observed in mouse fibroblast cell line (NIH3T3) as normal control. Further investigation shows that the rsTRAIL could also kill primary tumor cells isolated freshly from patients with cardiac cancer, breast cancer and malignant thymoma, while the normal human peripheral blood lymphocytes are not killed under the same conditions. These results provide new evidence that rsTRAIL could induce apoptosis of tumor cells specifically and it could be a new promising medicine for tumor therapy.     

低氧条件下巨噬细胞分泌CCL22促进三阴乳腺癌转移

三阴乳腺癌(Triple Negative Breast Cancer, TNBC)是乳腺癌中恶性程度最高的一种亚型，表现为很高的转移潜能。巨噬细胞，即肿瘤相关巨噬细胞(Tumor-Associated Macrophages, TAM)，在促进TNBC转移中起了重要作用。乳腺癌作为一种实体肿瘤，往往处于缺氧环境中。低氧环境能够促进癌细胞的转移，然而低氧环境中巨噬细胞在促进肿瘤转移中的作用仍然不清楚。在该研究中，THP1细胞被诱导成TAM，经过缺氧培养后，通过Transwell实验检测其促进三阴乳腺癌细胞BT-549和MDA-MB-231的细胞迁移能力；通过尾静脉注射，将MDA-MB-231细胞移植于祼鼠体内，CT扫描，分析了TAM促进TNBC细胞的器官转移能力；通过ELISA实验检测低氧对TAM分泌的肿瘤转移相关因子的影响，通过GDSC在线软件分析了CCL22受体CCR4和其他CCR在乳腺癌组织与正常组织中表达的差异。结果表明低氧条件下巨噬细胞通过分泌CCL22的表达来促进三阴乳腺癌细胞迁移:经过缺氧培养后的TAM显著增强了TNBC细胞迁移能力，以及促进癌细胞在体内向肺转移；低氧诱导TAM分泌CCL22；CCL22受体CCR4在乳腺癌组织中的表达显著高于在正常组织中的。