重组人甲胎蛋白基因顺式调控元件功能的研究

将６种含有人甲胎蛋白（ＡＦＰ）基因启动子、增强了和／或沉寂子不同组合的荧光素酶报告基因真核表达载体分别转染３种人肝癌细胞系及１种肺腺癌细胞系，测定瞬时表达的荧光素酶活性。结果显示６种重组人ＡＦＰ基因顺式作用元件在ＡＦＰ阳性肝癌细胞均具有特异启动活性，而在ＡＦＰ阴性的肝癌细胞和非肝癌细胞无启动活性。在这６种重组人ＡＦＰ顺式元件中，以２．２ｋｂ的调控元件（去除了ＡＦＰ基因沉寂子。保留其启动子和增强子序列）启动活性最高，从而为下一步的靶向性肝癌基因治疗提供了较理想的肝癌细胞特异性启动元件。     

携带hIL-2cDNA的逆转录病毒载体的构建及其在人肝癌细胞中的特异表达研究

将人白细胞介素２（ｈＩＬ-２）ｃＤＮＡ克隆到逆转录病毒载体ＭＮＳＭ的ＰＬ位点　，分别构建了转录受ＳＶ４０早期启动子和人甲胎蛋白增强子调控的重组逆转录病毒载体ＭＮＳＩ和ＭＮＳＩＡ。用脂质体转染法将ＭＮＳＩ和ＭＮＳＩＡ分别转导ＰＡ３１７包装细胞，测质粒转染率为（５～２０）×１０~(－３)克隆／μｇＤＮＡ·１０~６细胞，病毒感染率为（５．４～４５０）×１０~４ＣＦＵ／ｍｌ。重组病毒在４μｇ／ｍｌ ｐｏｌｙｂｒｅｎｅ存在条件下感染人肝癌细胞、肾癌细胞和黑色素瘤细胞，Ｎｅｏ~Ｒ克隆经Ｓｏｕｔｈｅｒｎｂｌｏｔ分析证明ｈＩＬ－２ｃＤＮＡ转入人肿瘤细胞并整合，　Ｒ　ＮＡ斑点杂交及ＩＬ－２活性表达分析证明，人甲胎蛋白增强子可促进异源启动子启动ｈＩＬ－２ｃＤ－ＮＡ在合成甲胎蛋白的人肝癌细胞中高效特异转录和表达。该研究对肝癌特异性免疫增强基因治疗有重要意义。     

人睫状神经营养因子在基因在大肠杆菌中的表达

目的 克隆人睫状神经营养因子（ｈＣＮＴＦ）基因，并大大肠杆菌宿主系统中高效表达出具有生物活性的ｈＣＮＴＦ蛋白。方法 从人外周神经组织总ＲＮＡ经逆转录－聚合酶链反应（ＲＴ－ＰＣＲ）扩增得到编码人ＣＮＴＦ的全长ｃＤＮＡＡ片段，此片段经回收和纯化后克隆进ＰＧＥＭ－５Ｚｆ（＋）质粒载体，并进行了ＤＮＡ序列分析，然后进一步亚克隆进Ｔ７启动子表达载体，用ＩＰＴＧ在大肠杆菌主中诱导ｈＣＮＴＦ蛋白表达，并以体外培     

逆转录病毒载体介导入GM—CSF基因转染肿瘤细胞

应用逆转录病毒载体ｐＺＩＰＮｅｏＳＶ介导入ＧＭ－ＣＳＦ基因转染肿瘤细胞获得表达。经Ｌｉｐｏｆｅｃｔｉｎ将含有人ＧＭ－ＣＳＦ基因的重组逆转录病毒功茶ｐＺＩＰ－ＧＭ转染兼性病毒包装细胞系ＰＡ３１７，继之用病毒睡获感染人肝癌细胞ＳＭＭＣ７７２１和人胃癌ＢＧＣ－８２３，经ＧＭ－ＣＳＦＪ依赖细胞株ＴＦ１活活和双抗体夹心法ＥＬＩＳＡ法测定表明：人ＧＭ－ＣＳＦ基因在人肿瘤中获得稳定高效表达。     

逆转录病毒载体介导人GM－CSF基因转染肿瘤细胞

应用逆转录病毒载体ｐＺＩＰＮｅｏＳＶ（Ｘ）介导人ＧＭ－ＣＳＦ基因转染肿瘤细胞获得表达。经Ｌｉｐｏｆｅｃｔｉｎ将含有人ＧＭ－ＣＳＦ基因的重组逆转录病毒载体ｐＺＩＰ－ＧＭ转染兼性病毒包装细胞系ＰＡ３１７，继之用病毒收获液感染人肝癌细胞ＳＭＭＣ７７２１和人胃癌ＢＧＣ－８２３，经ＧＭ－ＣＳＦ依赖细胞株ＴＦ１测活和双抗体夹心法ＥＬＩＳＡ测定表明：人ＧＭ－ＣＳＦ基因在人肿瘤细胞中获得稳定高效表达。为进─步建立ＧＭ－ＣＳＦ的转基因治疗模型提供了基础。     

脂质体转染AFP基因构建树突状细胞肝癌瘤苗及体外活性检测

目的：探讨以ＡＦＰ为靶点，构建ＡＦＰ－ＤＣ肝癌瘤苗及其抗肝癌免疫治疗的可能性。方法：应用脂质体将ＡＦＰ基因转染体外培养的未成熟 ＢＭＤＣ，构建 ＡＦＰ－ＤＣ肝癌瘤苗，以流式细胞术、Ｗｅｓｔｅｒｎ ｂｌｏｔ、３Ｈ－ＴｄＲ法和 ＭＴＴ法等检测其免疫活性。结果：ＡＦＰ－ＤＣ瘤苗不仅能产生和分泌ＡＦＰ，而且能上调自身的Ｂ７分子和ＭＨＣ分子，明显刺激Ｔ细胞增殖及提高ＣＴＬ的杀伤作用。结论：提示肝癌相关基因ＡＦＰ可作为抗肝癌基因治疗的切入点。     

人IL-12的克隆、表达及生物活性的鉴定

目的：克隆中国人ＩＬ－２ｐ４０基因,构建ＩＬ－１２的真核基因表达载体。方法：采用ＲＴ－ＰＣＲ从北京地区人脐血树突状细胞（ＤＣ）中克隆ＩＬ－１２ｐ４０ｃＤＮＡ基因,并进行序列分析。利用ｐｃＤＮＡ３．１和ｐＬＸＰＸＳＮ构建ＩＬ－１２表达载体,转染人肝癌细胞后对其进行生物学和免疫学分析。结果：北京地区人ＤＣ中ＩＬ－１２ｐ４０ｃＤＮＡ基因２１０位密码子有独特的结构,为ＧＣＣ（Ａｌａ）。并且２３９和２９１位     

Epstein-Barr病毒载体介导的白细胞介素12在肝癌细胞中的靶向表达

目的研究白细胞介素－１２（Ｉｎｔｅｒｌｅｕｋｉｎ－１２，ＩＬ－１２）在肝癌细胞靶向性表达，探索肝癌基因治疗新方法。方法将白介素－１２分别克隆到带有人甲胎蛋白启动子和增强子的Ｅｐｓｔｅｉｎ－Ｂａｒｒ（ＥＢ）病毒载体中，得到重组表达载体ｐＥＢＡＦ／Ｐ３５和ｐＥＢＡＦ／Ｐ４０，分别在４种细胞系中作共转染，用逆转录－聚合酶链反应（ＲＴ－ＰＣＲ）、酶联免疫吸附试验（ＥＬＩＳＡ）和Ｗｅｓｔｅｒｎｂｌｏｔ检测各细胞系中ＩＬ－１２的表达情况。结果用ｐＥＢＡＦ／Ｐ３５和ｐＥＢＡＦ／Ｐ４０共转染４种细胞后ＩＬ－１２基因只在产生甲胎蛋白的肝癌细胞（ＨｅｐＧ２）中表达，活性检测证明，表达的ＩＬ－１２有诱使ＩＦＮ－γ产生的生物学活性。结论本研究在肝癌细胞中靶向性和组织特异性的表达了有活性的ＩＬ－１２，为既能杀死肝癌细胞，又不影响正常肝细胞功能的新型基因治疗方案做了有益的探索。     

人GM－CSF基因在昆虫细胞中表达的研究

本工作构建的昆虫表达重组体ｐＡＣ６１０－ＧＭＴ，是在ＡｃＭＮＰＶ的Ｐｏｌｙｈｅｄｒｉｎ启动子控制下，表达去除了信号肽编码顺序的人ＧＭ－ＣＳＦ基因（ｃＤＮＡ）的转染载体。它与野生ＡｃＭＮＰＶ病毒ＤＮＡ共转染Ｓｆ２１细胞，经过筛选得到纯化的可表达人ＧＭ－ＣＳＦ的重组病毒株ｖＡｃＧＭＴ。其感染细胞总ＲＮＡ的Ｎｏｒｔｈｅｒｎ分析结果表明，重组病毒在ｍＲＮＡ水平有人ＧＭ－ＣＳＰ特异性表达，其表达水平在感染后４８ｈ时达高峰，７２ｈ未见明显下降。感染细胞裂解物的Ｗｅｓｔｅｒｎ－Ｂｌｏｔ分析和活性测定也证实其蛋白水平的表达，并有人ＧＭ－ＣＳＦ的生物学活性。     

p53基因结构与功能研究的新进展

ｐ５３蛋白的信号区有１个ＳＨ－３区结合部位,非专一ＤＮＡ结合区可促进顺序专一的ＤＮＡ结合区与ＤＮＡ损伤部位结合。ｐ５３蛋白可整合细胞对各种危急情况的反应,其信息传递途径上游是各种危急状况,有ＡＴＭ类的基因起作用。ｐ５３蛋白通过靶基因ｐ２１ＷＡＦ－１及ＧＡＤＤ４５调控Ｇ１关卡,也参加了Ｇ２／Ｍ关卡的调控;通过上调靶基因Ｂａｘ、ＩＧＦ－ＢＰ－３,抑制ＢｃＬ－２基因表达,调控凋亡;维持基因组的遗传学稳定性,行使抑瘤基因功能。     

细胞因子受体-嵌合抗体真核表达载体的构建

目的：构建细胞因子受体-抗人AFP嵌合抗体基因真核表达载体。方法：用RT-PCR方法从人胚肝组织中扩增EpoR胞外区基因及gp130跨膜区基因，并用限制性酶切连接方法拼接。用PCR方法从抗人AFP单链抗体表达载体中扩增VL、VH基因，分别与人kappa轻链和人gammal重链恒定区基因重组，获得人鼠嵌合轻链和重链，再将EpoR-gp130与嵌合重链连接，最后将嵌合轻链和H—EpoR-gp130分别连接到质粒pVITRO上，构建pVITRO-E-g-Ig载体。结果：获得EpoR胞外区基因750bp，gp130跨膜区基因900bp。重组真核表达载体经限制性酶切鉴定示EpoR、gp130基因、嵌合重链基因和嵌合轻链基因正确连接到载体pVITRO。结论：成功构建细胞因子受体-抗人AFP嵌合抗体基因表达载体。     

AFP增强子驱动的HSV-TK/GCV自杀基因系统对肝癌细胞杀伤的实验研究

目的探讨人AFP增强子驱动的单纯疱疹病毒胸苷激酶/丙氧鸟苷（HSV-TK/GCV）自杀基因系统体外靶向杀伤肝癌细胞效应。方法构建人AFP增强子驱动的pAFP-CDNA3.1-TK自杀基因真核表达质粒,脂质体转染肝癌细胞,检测TK mRNA和蛋白表达,MTT法检测GCV对肝癌细胞的杀伤作用。结果成功构建pAFP-CDNA3.1-TK自杀基因真核表达质粒,在AFP阳性HepG2细胞中检测到TK mRNA和蛋白表达,添加GCV可特异性地杀伤HepG2细胞,而AFP阴性的SMMC7721细胞生长不受影响。结论 AFP增强子驱动的TK/GCV自杀基因系统可以靶向杀伤AFP阳性肝癌细胞。     

AFP启动子驱动的yCD/TK双自杀基因靶向杀伤肝癌细胞的体内外研究

目的： 研究携带甲胎蛋白（AFP）启动子的酵母菌胞嘧啶脱氨酶/胸苷激酶（yCDglyTK）双自杀基因体内外靶向性杀伤肝癌细胞的效果和机制。方法: 构建携带AFP启动子的yCD/TK双自杀基因表达质粒。通过阳离子脂质体将携带AFP启动子的yCD/TK双自杀基因转染HepG2和SMMC7721细胞,用MTT法测定不同浓度氟胞嘧啶（5-FC）、更昔洛韦（GCV）及联合治疗的杀伤作用,用流式细胞仪检测细胞周期。建立裸鼠肝癌皮下种植瘤模型,观察自杀基因体内杀瘤效果以及细胞凋亡的情况。结果: 成功构建的携带AFP启动子的yCD/TK双自杀基因靶向性地在AFP阳性的HepG2细胞上表达,而AFP阴性的SMMC7721细胞无表达,GCV、5-FC及两者联合可有效抑制HepG2细胞生长,随药物浓度的增高而杀伤作用增强,药物间抑瘤效果比较是GCV＋5-FC＞5-FC＞GCV,而SMMC7721细胞的生长未受影响。体内实验可见GCV、5-FC及两药联合对转染后的HepG2细胞种植瘤有明显的抑制效果,并检测到明显的细胞凋亡,而对SMMC7721细胞种植瘤的生长无影响,种植瘤内极少凋亡细胞。结论: 携带AFP启动子的yCD/TK双自杀基因能有效地靶向性地杀伤AFP阳性的肝癌细胞,细胞凋亡可能是其杀伤的重要机制之一。     

表达人粒细胞—巨噬细胞集落刺激因子逆转录病毒载体的构建

构建了ｈＧＭ－ＣＳＦ ｃＤＮＡ逆转录病毒载体，将其分别转染甲胎蛋白表达阳性和阴性的肝癌细胞系Ｈｕ－Ｈ７和ＨＬＥ。结果，ｈＧＭ－ＣＳＦ在两种人肝癌细胞系中有表达。表达产物能分泌到肝癌细胞外，分泌到细胞的产物用ＴＦ－１细胞检测证明具有生物学活性。     

载TK基因聚丙交酯乙交酯纳米粒的制备及有关性质研究

我们构建了含AFP启动子、TK基因和EGFP真核表达载体重组的质粒，并以可生物降解、生物相容的高分子载体材料PLGA包埋制成载自杀基因的纳米粒。结果表明纳米粒形态圆整，大小均匀，平均粒径68nm，包封率可达80%，该纳米粒能显著提高质粒DNA抵抗核酸酶降解和超声波剪切的能力。     

Immuno-suppressive Effect of Human Alphafetoprotein: A Cross Species Study

Alphafetoprotein (AFP) is the major serum protein of fetal life in human and other mammalian species. The phylogenetical concervatism of AFP demonstrated by extensive Immunological cross reaction between human AFP and AFP of a number of species, suggest that AFP plays a general role in the successful pregnancy of all mammalian species. The present work clearly demonstrates the antiproliferative effect of human AFP on lymphocytes, harvested from normal human donors. The Inhibitory effect of human AFP is quite significant in the same dose during blastic transformations of the lymphocytes. In this study, peripheral blood mononuclear cells were Induced to blastic transformations with phytohaemagglutinin (PHA-M) and the effect of AFP was quantified by the Incorporation of [³H]-thymidine into newly synthesized DNA during 24 hrs pulse. Moreover, human AFP shows similar immuno-suppressive effect to other species of lymphocytes also. In all the three species (mouse, rat and hamster) studied, a parallelsm was noted In their respective percentage of thymidine incorporation values at the comparable doses. These results establish a cross species inhibitory effect of human AFP and it may be stated that this effect is directly targeted on T-helper cells and has no Interaction with interleuk in-2 (IL-2).     

IL-4基因转染诱导肝母细胞瘤分化及抑制端粒酶活性

目的 研究人白细胞介素４（ｈｕｍａｎ ｉｎｔｅｒｌｅｕｋｉｎ－４,ｈＩＬ－４）基因转染对肝母细胞瘤细胞的诱导分化和对端粒酶活性的影响。方法 以逆转录病毒载体（ＰＬ－ＩＬ－４－ＳＮ）将ｈＩＬ－４基因导入人肝母细胞瘤细胞系Ｈｅｐ Ｇ２细胞。台盼蓝拒梁,放射免疫测定,流式细胞仪细胞周期分析,原位杂交,ＰＣＲ－ＥＬＩＳＡ等方法检测基因转染后细胞形态,甲胎蛋白合成,原癌基因的表达及端粒酶活性变化。     

Characterization of somatic cell hybrids exhibiting extinction of AFP,Albumin and an AFP-HPRT Transgene

We utilized an AFP-HPRT transgene, i.e. the HPRT coding sequences under the regulation of AFP enhancer and promoter sequences, to localize the AFP extinguisher locus in intertypic somatic cell hybrids (hepatoma X fibroblast). This hybrid gene construct, which directly links AFP regulation to a reversibly selective gene, enabled the selection of stably transfected cells which express AFP, as well as cells showing extinction of AFP. Mouse hepatoma cells stably transfected with and expressing the transgene were fused to human fibroblasts, and the resulting somatic cell hybrids were characterized using Southern, Northern and karyotypic analyses. That several hybrids exhibited the proper extinction of AFP, AFP-HPRT and albumin suggests coregulation of these genes by an extinguisher. Segregant lines derived from these hybrids were selected for the loss of extinguisher activity and for reexpression of the transgene. Karyotypic analysis of hybrid and segregant lines, exhibiting proper AFP, albumin and AFP-HPRT phenotypes, revealed that the presence of human chromosome 7 was most closely associated with the AFP-extinguished state. The hybrids generated in these studies now make it possible to isolate the sequences responsible for AFP and albumin extinction.     

Immuno-suppressive Effect of Human Alphafetoprotein: A Cross Species Study

Alphafetoprotein (AFP) is the major serum protein of fetal life in human and other mammalian species. The phylogenetical concervatism of AFP demonstrated by extensive Immunological cross reaction between human AFP and AFP of a number of species, suggest that AFP plays a general role in the successful pregnancy of all mammalian species. The present work clearly demonstrates the antiproliferative effect of human AFP on lymphocytes, harvested from normal human donors. The Inhibitory effect of human AFP is quite significant in the same dose during blastic transformations of the lymphocytes. In this study, peripheral blood mononuclear cells were Induced to blastic transformations with phytohaemagglutinin (PHA-M) and the effect of AFP was quantified by the Incorporation of [³H]-thymidine into newly synthesized DNA during 24 hrs pulse. Moreover, human AFP shows similar immuno-suppressive effect to other species of lymphocytes also. In all the three species (mouse, rat and hamster) studied, a parallelsm was noted In their respective percentage of thymidine incorporation values at the comparable doses. These results establish a cross species inhibitory effect of human AFP and it may be stated that this effect is directly targeted on T-helper cells and has no Interaction with interleuk in-2 (IL-2).