用于活体成像的小鼠肺癌移植瘤模型的建立

本研究旨在建立可用于活体成像的小鼠肺癌移植瘤模型。利用脂质体将荧光素酶表达载体pGL4.17(luc2/neo)转染至人非小细胞肺癌细胞株A549,经G418筛选获得稳定表达荧光素酶的细胞克隆。根据体外生物发光情况及细胞的生长特性,从中挑选合适克隆,进行裸鼠皮下接种,SCID鼠尾静脉接种,建立肺癌移植瘤模型。利用活体成像系统监测肿瘤的生长转移情况,并用切片HE染色进一步验证小鼠模型移植瘤的原位成瘤和转移能力。实验结果表明:本研究成功地构建了可用于活体成像的小鼠肺癌移植瘤模型,模型稳定可靠、直观、灵敏,为肿瘤生长转移机制的研究及抗肿瘤药物的研发提供了重要工具。     

耐热荧光素酶的表达及热稳定焦磷酸测序体系的建立

焦磷酸测序是一种基于生物发光反应的实时DNA序列测定技术,其反应体系中的荧光素酶决定测序反应的灵敏度。传统焦测序反应使用的是野生型北美荧光素酶Photinus pyralis luciferase(PpL),该酶热稳定性较差,因此由该酶配制的焦磷酸测序反应体系对热不稳定,影响焦磷酸测序的灵敏度。为了建立热稳定的焦磷酸测序反应体系,全合成了耐热突变日本萤火虫荧光素酶的编码序列,并将其插入到表达载体pET28a(+)中构建重组质粒,将重组质粒转化到大肠杆菌中,筛选得到的阳性重组菌成功表达了N端带有6×His(组氨酸)标签的耐热突变日本萤火虫荧光素酶。利用镍亲和层析法,纯化得到了分子量约为60 kDa且比活为4.29×1010RLU/mg的重组蛋白。对重组耐热日本萤火虫荧光素酶的热稳定性研究结果表明,该酶在50℃时仍具有活性,在40℃下孵育25 min后活性保留了90%以上。与基于野生型北美荧光素酶的焦磷酸测序体系相比,由耐热日本萤火虫荧光素酶配制的测序反应体系对热稳定性有了极大的提高,该测序反应液在37℃放置1 h后仍能够得到正确的测序结果。研究结果为建立稳定可靠的现场及时快速焦磷酸测序反应体系奠定了基础。     

基于AAVS1位点构建稳定表达Cas9蛋白的非小细胞肺癌细胞系

该研究旨在利用CRISPR/Cas9介导的同源重组技术将Cas9基因序列整合入非小细胞肺癌A549细胞基因组中的AAVS1位点,建立稳定表达Cas9蛋白的A549单克隆细胞系。该技术避免了Cas9基因随机整合进入基因组带来的潜在风险。通过PCR、Western blot、CCK-8、STR技术分别检测A549单克隆细胞系的插入位点、Cas9蛋白水平、细胞增殖能力、基因编辑能力以及细胞身份信息。上述结果显示,在单克隆细胞系A549 Cas9-copGFP-1中Cas9基因准确插入至AAVS1安全位点并高表达Cas9蛋白,细胞增殖能力未发生改变。此外,该细胞还具有良好的基因编辑能力,细胞身份信息准确无误。总之, A549 Cas9-copGFP-1细胞可用于进一步的基因编辑,为肺癌相关基因的高通量筛选和功能性研究提供一种有力工具。     

慢病毒介导荧光素酶表达的人鼻咽癌细胞小鼠模型的建立

目的：建立荧光素酶标记的人鼻咽癌细胞裸鼠模型,活体成像系统监测肿瘤的生长并与肿瘤的体积进行对比。方法：构建表达荧光素酶基因2（1uc2）的慢病毒载体,与辅助质粒共转染293T细胞以制备慢病毒,感染人鼻咽癌SUNEl细胞后经嘌呤霉素筛选获得表达luc2的细胞株。活体成像设备体外检测不同数量细胞的发光强度,最后以5×10 6个细胞皮下接种BALB／cnu／nu裸鼠,活体成像系统动态记录接种后肿瘤的信号并与肿瘤的体积对比。结果：成功构建慢病毒表达质粒pLenti．1uc2并包装出慢病毒颗粒,病毒感染后嘌呤霉素筛选6天得到鼻咽癌细胞株SUNEl一luc2。细胞株传代后有稳定的发光强度,且经活体检测的每秒光子数与细胞数成正相关（R2=0．96）;活体成像观察发现裸鼠接种第2天接种部位的发光强度就达到3-2×10^8,而且成瘤过程中发光强度的变化与肿瘤大小一致。结论：成功构建适用于活体成像的人鼻咽癌SUNEl细胞的裸鼠成瘤模型,该模型从细胞接种开始即可有效动态监测鼻咽癌皮下瘤的生长及转移,从而为鼻咽癌的成瘤机制及药物干预研究提供一个新的手段。     

稳定表达大鼠GCLC启动子及荧光素酶报告基因细胞株的建立

目的:建立稳定表达大鼠谷氨酰半胱氨酸合成酶催化亚单位(GCLC)启动子及荧光素酶报告基因的大鼠肺泡上皮细胞株。方法:克隆大鼠GCLC上游5.9kb的启动子序列并构建重组报道载体PGL4.19-GCLC-LUC,转染到大鼠Ⅱ型肺泡上皮细胞L2,经G418筛选以获得单细胞抗性克隆并在传代过程中能稳定表达荧光素酶活性;检测细胞荧光素酶表达与细胞数量相关性;PCR检测稳定细胞株基因组已整合的插入片段;刺激因子刺激6h,检测稳定细胞株的反应性。结果:成功构建PGL4.19-GCLC-LUC;构建的稳定细胞株能稳定地表达荧光素酶,且与细胞数量正相关;PCR检测稳定细胞株目的片段稳定整合基因组;TNF-α刺激后,能使荧光素酶活性上升,差异有统计学意义(P0.05);Rapamycin,GSH-EE刺激后,荧光素酶活性显著下降(P0.05)。结论:成功构建稳定表达大鼠GCLC启动子及荧光素酶报告基因的细胞株,将为高通量药物筛选以及进一步研究GCLC基因的转录调控提供重要的细胞研究手段。     

稳定表达HLA-A33蛋白细胞系的建立

旨在构建能稳定表达HLA-A33蛋白的细胞系,并观察其在细胞中的表达水平.首先克隆取得HLA-A33基因,并将其插入慢病毒载体,经酶切和测序鉴定,确定载体构建正确.通过慢病毒系统感染正常RD细胞,将HLA-A33基因整合进RD细胞的基因组.提取构建细胞系的基因组做PCR鉴定,并通过免疫荧光和蛋白免疫印迹法检测,结果显示,HLA-A33基因成功整合入RD细胞基因组中,且在重组细胞系中成功表达.该细胞系可为A33等位基因与HBV感染后的慢性化以及EV71感染的相关研究提供试验参考.     

MDR1基因单靶点双荧光素酶报告基因系统的建立

目的通过构建以MDR1启动子为启动序列的双荧光素酶报告基因系统并进行活性分析,为MDR1基因表达的单靶点调控研究和逆转剂的筛选提供一种有效的方法。方法从HCT-8细胞中提取DNA并克隆含有MDR1基因启动子中Y—box序列。将该序列重组到萤光素酶报告基因载体pGL-3．Basic的启动区域中,从而构建报告基因载体pGL-MDR1。将pGL-MDR1和pRL-TK载体共转染到HCT-8和HCT-8／VCR细胞中。通过调节不同载体的比例来优化转染效率。利用MDRI基因激活剂（热诱导）和抑制剂（EGCG）等处理来分析其启动转录活性受外界因素的影响。结果通过直接测序法验证了pGL-MDR1含有MDR1基因启动子Y—box序列且没有出现碱基突变。在pGL-MDR1和pRL-TK的转染比例为5：5时,转染效率最高并具有最高的萤光素酶活性。通过MDR1基因激活处理后表现为时间依赖性地激活MDR1基因的表达,而MDR1基因抑制剂的作用则相反。结论MDR1启动子为启动序列的双荧光素酶报告基因系统建立成功。该系统不但可以用于研究活体生物发光成像和MDRI基因表达的机理,而且可用于单靶点的多药耐药抑制剂的筛选。     

p100蛋白表达抑制的HepG2肝癌细胞稳定株的建立

目的建立p100表达抑制的HepG2肝癌细胞稳定株,并初步探讨p100在HepG2肝癌细胞中的功能。方法用脂质体将含有真核细胞筛选标记Neo和GFP的p100 shRNA表达质粒转染入HepG2细胞。经G418耐药筛选稳定整合抗药基因的细胞单克隆;荧光镜检GFP阳性细胞单克隆,挑取单克隆;Western检测HepG2细胞稳定株HepG2（p100I）中p100表达的抑制效果;平板细胞克隆形成实验检测细胞克隆形成能力;MTS法检测细胞存活;划痕实验检测细胞迁移能力。结果成功获得了p100表达抑制的HepG2肝癌细胞稳定株HepG2（p100I）,其中p100的表达明显降低。并且实验表明,该p100表达抑制稳定株的克隆形成能力,抵抗化疗药物Cisplatin诱导的细胞死亡的能力和迁移能力明显低于对照组细胞。结论p100表达抑制的HepG2肝癌细胞稳定株的建立为研究p100蛋白在肝癌中的作用提供了体外细胞系模型,基于此稳定株的研究,发现p100能够影响HepG2肝癌细胞的多种细胞功能。     

表达马传染性贫血病毒受体和荧光素酶报告基因的293细胞系的建立

为了在体外精确、简便地测定马传染性贫血病毒(EIAV)的中和抗体和研究不同毒株与受体的亲和性,克隆了马慢病毒受体1(ELR1)cDNA并插入真核表达载体pcDNA3.1( ),构建了表达载体pELR1。该载体瞬时转染293细胞后,经Western blot和间接免疫荧光(IFA)检测,确认了ELR1的表达。在pELR1质粒的基础上,插入EIAV疫苗株前病毒基因组转录调控区LTR以及萤火虫荧光素酶报告基因(Luc)构建了表达载体pELR1-LTR-Luc,并转染293细胞,建立了ELR1-LTR-Luc(293-E)细胞系。该细胞系能稳定表达ELR1基因,并且能在LTR的调控下表达萤火虫荧光素酶基因。用1000TCID50的EIAV驴胎皮肤细胞疫苗株D18V13接种该细胞,24h后检测其荧光素酶活性是未接毒对照的3.15倍。同时用IFA检测证明了病毒在细胞内的增殖。EIAV强毒株L21的接毒试验显示,ELR1-LTR(293-E)细胞的萤火虫荧光素酶活性与该毒株的接毒量在10-2~10-7稀释范围内呈正相关。该细胞系传35代后,外源基因的表达特征未发生改变。该细胞系的建立为进一步开展EIAV与细胞受体相互作用以及中和抗体评价等研究奠定了重要基础。     

稳定表达ALB启动子及荧光素酶报告基因的肝干细胞株的构建

目的构建稳定表达ALB启动子及荧光素酶报告基因的肝干细胞株。方法PCR扩增获得ALB启动子,并与pBGLuc连接获得携带ALB启动子及荧光素酶报告基因的pBGLuc—ALB质粒,脂质体转染质粒到不同细胞,ALB—GLuc活性检测功能。构建逆转录病毒,感染HP14．5肝干细胞株获得携带ALB启动子及荧光素酶报告基因的稳定细胞株,经Dex、HGF体外诱导后第3、6、9、12天ALB—GLuc检测荧光素酶活性,免疫荧光检测ALB的表达。结果PCR、酶切及测序结果显示ALB启动子正确插入至荧光素酶GLuc基因上游,HEK293、HP14．5、LC14d及Hepa1-6细胞中ALB—GLuc活性与免疫荧光结果一致。HP14．5ALB—Gluc稳定细胞株在高浓度的稻瘟菌素中存活,免疫荧光结果显示Dex、HGF诱导后细胞中ALB的表达逐渐增强,并与ALB—Gluc活性升高一致。结论成功构建了稳定表达ALB启动子及荧光素酶报告基因的肝干细胞株,为研究肝干细胞的体外成熟分化提供了重要的细胞手段。     

稳定表达hHCN2基因 HEK293细胞系的建立

目的：培育稳定表达hHCN2基因的细胞系,建立一种表达研究心肌离子通道的有效模型。方法：通过脂质体转染的方法,将重组pcDNA3-hHCN2真核表达载体导入人胚肾细胞（HEK293细胞）,以G418压力筛选转染细胞,并对其进行全细胞膜片钳记录。结果：经600μg／ml压力筛选后,获得抗性细胞克隆,并用全细胞膜片钳技术记录到克隆hHCN2通道编码电流。结论：本实验采用脂质体转染法成功地培育出G418抗性HEK293细胞。为进一步研究克隆离子通道结构和功能的关系奠定基础。     

Characterization of cell lines stably expressing human normal or mutated EGFP-tagged MC4R

The melanocortin receptor type 4 (MC4-R) is involved in food intake and represents a potential target for the treatment of some forms of obesity. The fluorescent protein EGFP was fused to the wild-type or mutated coding sequence of the human MC4-R. After transfection in HEK 293, clones stably expressing hMC4-R-EGFP were selected. Wild-type chimeric hMC4-R was well addressed to the cell membrane as demonstrated using confocal microscopy and displayed the same pharmacological characteristics as native hMC4R. NDP-alpha MSH induced a time-dependent internalization of MC4-R that was partially prevented by AgRP. The two mutated chimeric receptors studied here (CTCT-deleted and C271A) showed a high alteration of their response to ligand and were retained inside the cells. In conclusion, we have developed a model of clones stably expressing EGFP-tagged-hMC4-R. This is the only such model available to date and it provides a useful tool to follow the trafficking of MC4-R inside living cells.     

Establishment of human embryonic stem cell line stably expressing Epstein-Barr virus-encoded nuclear antigen 1

Human embryonic stem (hES) cells have the capability of unlimited undifferentiated proliferation, yet maintain the potential to form perhaps any cell type in the body. Based on the high efficiency of the Epstein-Barr virus-based episomal vector in introducing exogenous genes of interest into mammalian cells, we applied this system to hES cells, expecting that this would resolve the problem of poor transfection efficiency existing in current hES cell research. Therefore, the first step was to establish EBNA1-positive hES cells. Using the Fugene 6 transfection reagent, we transfected hES cells with the EBNA1 expression vector and subsequently generated hES cell clones that stably expressed EBNA1 under drug selection. These clones were confirmed to express EBNA1 mRNA by RT-PCR and to express EBNA1 protein by Western blotting. Furthermore, luciferase reporter gene analysis was performed on the EBNA1 clones and revealed that the expressed EBNA1 protein was functional. When the EBNA1-positive cells were injected into severe combined immunodeficient (SCID) mice, they formed teratoma tissues containing all three embryonic germ layers and EBNA1 protein was detected in these teratoma tissues by Western blotting. All the results show that we have successfully created stable EBNAI-hES cells, thus laying a good foundation for further research.     

稳定表达β-synuclein的SH-SY5Y细胞株的构建

目的构建稳定表达β-synuclein的SH-SY5Y细胞株。方法利用脂质体转染技术将质粒pcD-NA3.1-β-synuclein转染SH-SY5Y细胞,通过Zeocin进行抗性筛选。采用原位免疫荧光、免疫组织化学染色及Western blot杂交检测β-synuclein在SH-SY5Y细胞中的表达情况;通过MTT比色法检测β-synuclein稳定表达对SH-SY5Y细胞增殖的影响。结果原位免疫荧光、免疫组织化学染色及Western blot检测结果显示β-synuclein在SH-SY5Y细胞中的表达水平较对照组明显升高;稳定表达β-synuclein的细胞增殖程度较对照组明显增高(P<0.05)。结论β-synuclein在SH-SY5Y细胞中稳定表达,为后续的研究提供有用的细胞模型。为进一步研究β-sy-nuclein对帕金森病发病神经保护作用的研究奠定了良好的基础。     

Establishment of stable human fibroblast cell lines constitutively expressing active Rho-GTPases

Summary. Small GTP-binding proteins of the Rho family (RhoA, Cdc42, Rac1) regulate the organisation and the turnover of the cell’s cytoskeleton and adhesion structures. A significant function of these cellular structures is to translate and counterbalance forces applied to, or generated by, cells in order to maintain homeostasis and control cell movement. We therefore hypothesised that Rho-GTPases are directly involved in cellular gravity perception and may participate in the alterations induced in microgravity. To define an adequate cellular model allowing to investigate this issue, we have established stable cell lines constitutively expressing active forms of either RhoA, Cdc42, or Rac1. The three cell lines differ by morphology and by their ability to form filopodia, lamellipodia, and bundles of actin stress fibers. Overexpression of the active form of either RhoA, Cdc42, or Rac1 is compatible with cell viability and does not affect cell population doubling time. Thus, our series of mutant cells appear well suited to gain further knowledge on the molecular mechanisms of cellular gravity perception. Correspondence and reprints: Institute for Biochemistry II, Joseph-Stelzmann-Strasse 52, 50931 Cologne, Federal Republic of Germany.     

转录病毒载体介导的稳定表达口蹄疫病毒3D基因的BHK21细胞系的建立

[目的]研究口蹄疫病毒RNA聚合酶在BHK-21细胞中的稳定表达状况,为研究RNA聚合酶生物学活性及其基囚工程疫苗研制提供科学依据.[方法]从重组质粒pMD18-T-3D扩增口蹄疫病毒3D基因,通过分子克隆技术构建莺组逆转录病毒表达载体pBPSTR1-3D.用pBPSTR1-3D和pVSV-G双质粒瞬时转染GP2-293包装细胞,收获重组逆转录病毒,然后感染BHK-21细胞,嘌呤霉素持续筛选12 d后获得阳性克隆,并用有限稀释法挑选单个阳性细胞克隆.[结果]应用PCR、RT-PCR技术可从体外反复传代的阳性细胞中扩增到3D基因,证实目的外源基因能转录并被稳定整合进宿主细胞基因组中.经SDS-PAGE、Western blot、间接免疫荧光检测到在不同代次的阳性细胞中有目的蛋白表达.[结论]本试验利用逆转录病毒载体介导的基因转移技术,将外源基因插入到靶细胞的基因组中,构建了稳定表达口蹄疫病毒RNA聚合酶的包装细胞系,为研究3D基因表达及其蛋白定位提供了方便,也为下一步研究RNA聚合酶生物学功能和疫苗研制提供了科学依据.     

Human cell lines stably expressing HIV env and tat gene products

A DNA fragment containing the tat, rev and env genes of the human immunodeficiency virus type 1 was inserted into the retroviral vector pZIPneoAU3. The resulting plasmid penvAU3 was transfected into HeLa and psi CRIP cells. Resulting recombinant retroviruses were used to infect HeLa and Jurkat cells. Immunoprecipitation analysis of stable transformants showed the expression of HIV env glycoproteins gp160, gp120 and gp41. Transactivation assays with a plasmid containing the gene for chloramphenicol acetyltransferase linked to HIV promoter-enhancer sequences demonstrated the expression of functional tat. These cells constitute virus-free tools for functional and structural studies of native env and tat.     

稳定表达结核分枝杆菌ESAT-6蛋白的RAW264.7细胞系的建立

为研究结核分枝杆菌Mycobacterium tuberculosis分泌蛋白ESAT-6 (Early secreted antigenic target of 6 kDa) 对巨噬细胞相关功能的影响,将正确构建的重组质粒pEGFP-C1-ESAT-6和空载体pEGFP-C1以脂质体介导的方法转染至小鼠巨噬细胞RAW264.7中,经过G418筛选后建立稳定表达EGFP-ESAT6融合蛋白以及EGFP的细胞系,并通过RT-PCR、荧光显微镜及Western blotting方法,在基因和蛋白两个水平对所建立的稳转细胞系进行鉴定。结果证实EGFP-ESAT6融合基因成功整合入RAW264.7细胞基因组并能够稳定表达,为后续的ESAT-6调控巨噬细胞机理研究提供了平台。     

Establishment and characterization of human colonic and gastric cancer cell lines

Two human cancer cell lines, DAIT-6 from a colonic cancer and IT-25 from a gastric cancer, derived from xenografts in nude mice have been established in tissue culture and maintained for over two years. In tissue culture, DAIT-6 cells grew in a monolayered sheet with a population doubling time of about 45.0 hr, and floated or piled up to form small buds above the monolayered surface in relatively confluent cultures. Chromosomal counts ranged from 40 to 108 with a modal number of 59. The cells secreted CEA (1.7 ng/1 x 10(6) cells/24 hr) and CA19-9 (540.5 u/1 x 10(6) cells/24 hr) in spent medium. The IT-25 cells grew in a monolayered sheet with a population doubling time of about 57.8 hr in tissue culture. The IT-25 cells also secreted CEA (0.5 ng/1 x 10(6) cells/24 hr) and CA19-9 (120.0 u/1 x 10(6) cells/24 hr) in spent medium. The xenografts for DAIT-6 and IT-25 in nude mice were histopathologically classified as a moderately differentiated tubular adenocarcinoma and a well differentiated tubular adenocarcinoma, respectively.