应用毕赤酵母系统表达人Fascin蛋白

背景与目的:应用酵母表达系统表达人的重要肿瘤分子标志物fascin蛋白。材料与方法:利用分子克隆技术将fascin基因完整编码区克隆至毕赤酵母(Pichia pastoris)分泌表达载体pPIC9中,获得重组质粒pPIC9-fascin;以限制性内切酶MssⅠ进行线性化并转化毕赤酵母GS115菌株,用PCR方法筛选出阳性整合克隆;对阳性克隆进行0.5甲醇诱导表达重组蛋白,银染及Western blot检测培养上清中fascin重组蛋白的表达情况。结果:毕赤酵母能够分泌表达约69kD的fascin重组蛋白,表达量为40μg/L。结论:毕赤酵母可以分泌表达fascin蛋白,但由于分泌表达量较低,尚达不到工程化要求。     

IL-7和EGFP双基因共表达重组腺病毒载体的构建

目的：构建白细胞介素7（IL-7）和增强型绿色荧光蛋白（EGFP）共表达的重组腺病毒载体,为进一步感染干细胞奠定基础。方法：将目的基因IL-7克隆到含有报告基因EGFP的穿梭质粒中,然后再将构建的重组穿梭质粒转移至pAdxsi载体中,构建重组腺病毒载体质粒,继而在H293细胞中扩增,纯化后测定病毒滴度。结果：pShuttle-EGFP-mIL7重组穿梭质粒经酶切鉴定得到0.5kb和5.1kb 2条带;pAdxsi-EGFP-mIL7重组腺病毒载体质粒经酶切鉴定得到14K、11.8K、3.1kb、2.66kb、2.47K、1.45K、0.6K 7条带;TCID50法测定纯化后的病毒滴度为2×10^10pfu/ml。结论：pAdxsi-EGFP-mIL7重组腺病毒载体构建成功。     

IL-7和EGFP双基因共表达重组腺病毒载体的构建

目的:构建白细胞介素7(IL-7)和增强型绿色荧光蛋白(EGFP)共表达的重组腺病毒载体,为进一步感染干细胞奠定基础。方法:将目的基因IL-7克隆到含有报告基因EGFP的穿梭质粒中,然后再将构建的重组穿梭质粒转移至pAdxsi载体中,构建重组腺病毒载体质粒,继而在H293细胞中扩增,纯化后测定病毒滴度。结果:pShuttle-EGFP-mIL7重组穿梭质粒经酶切鉴定得到0.5kb和5.1kb 2条带;pAdxsi-EGFP-mIL7重组腺病毒载体质粒经酶切鉴定得到14K、11.8K、3.1kb、2.66kb、2.47K、1.45K、0.6K 7条带;TCID50法测定纯化后的病毒滴度为2×1010pfu/ml。结论:pAdxsi-EGFP-mIL7重组腺病毒载体构建成功。     

人NKp44基因克隆及其在大肠埃希菌中的表达和纯化

目的:对人NKp44进行基因克隆及其在大肠埃希菌中重组表达,为进一步研究NK细胞抗肿瘤作用奠定基础。方法:提取人外周静脉血单个核细胞,培养并加入IL-2进行诱导后收集细胞,分离纯化外周血总RNA。用巢式PCR扩增hNKp44片段(约860bp),克隆至质粒载体pMD18-T,并对克隆的DNA片段进行序列分析。用限制酶EcoRⅠ和NcoⅠ消化pMD18-T-hNKp44重组质粒,分离hNKp44片段,并插入原核表达载体pET30a(+)的相应限制酶位点,酶谱分析鉴定重组表达载体pET30a(+)-hNKp44。转化菌株BL21(DE3)经IPTG诱导,用SDS-PAGE和WesternBlot鉴定表达的重组蛋白。采用His.BindPurificationKit对重组蛋白进行纯化。结果:巢式PCR扩增的DNA片段与hNKp44cDNA大小一致。重组质粒pMD18-T-hNKp44的DNA序列分析显示,克隆的DNA序列与文献报道的hNKp44的cDNA序列一致。SDS-PAGE表明,重组蛋白相对分子质量为35.4×103,其表达量达菌体总蛋白的40%左右。WesternBlot分析显示,重组蛋白能特异地与抗His.Tag抗体结合。纯化得到纯度为95%的重组蛋白,纯化回收率达40%。结论:已经成功地构建了表达重组hNKp44的工程菌株。     

血管基膜衍生多功能肽的表达及其生物活性的鉴定

目的: 在毕赤酵母中表达血管基膜衍生多功能肽(vascular basement membrane-derived mulifunctional peptide,VBMDMP),并鉴定其生物学活性.方法: 利用PCR技术获得融合了谷胱甘肽转移酶(GST)的肿瘤抑素(tumstatin)活性成分的GST-VBMDMP基因,克隆到pPIC9K载体;然后原生质体转化法转化毕赤酵母细胞,行多克隆筛选和表型鉴定.获得His Muts表型的转化子,在MGY培养液中30 ℃摇床培养,每24 h从培养液中转移1 ml培养液上清于-70 ℃保存,并保持培养瓶中培养液的量和培养液中甲醇0.5%的浓度不变,第9天行SDS-PAGE检测表达的蛋白并纯化,然后进行细胞和动物生物活性检测.结果: SDS-PAGE发现阳性重组子在MGY培养液中表达的蛋白量在1～7 d逐渐增加,到第8天后开始减少,用Glutathione Sepharose 4B亲和层析柱纯化获得GST-VBMDMP融合蛋白; GST-VBMDMP能抑制C57BL/6鼠动脉内皮细胞管状结构的形成;同时GST-VBMDMP( 2 、6 、10 mg/kg)对小鼠Lewis肺癌原发瘤(瘤重抑制率分别为96.6%、82.1%、61.2%)和自发性肺转移瘤(瘤结节抑制率分别为96.8 %、87.9%、75.3%)均具有明显的抑制作用(P＜0.01).结论:VBMDMP能够抑制鼠动脉内皮细胞管状结构的形成,并对小鼠Lewis肺癌原发瘤和肺转移具有明显的抑制作用.     

食管癌相关基因1编码蛋白的相互作用蛋白筛选

目的　筛选与食管癌相关基因 1(ECRG 1)编码蛋白相互作用的蛋白 ,为其功能研究奠定基础。方法　将编码ECRG 1羧基端 378个氨基酸的DNA序列插入到pGBKT7 DNA BD载体 ,与编码Gal4DNA结合结构域的DNA序列拼接做融合基因 ,将此重组质粒与已克隆到pACT2载体上的人肝脏cDNA文库 (与编码Gal4激活结构域的DNA序列融合 )共转化酵母细胞AH10 9。ECRG 1与相应的人肝脏cDNA片段编码的蛋白发生相互作用后 ,可激活报告基因的表达。排除假阳性后 ,阳性克隆中的文库cDNA进行测序分析。同源性检索搜寻GenBank中与之相同或相似的序列。结果　共转化得到约 3× 10 6个转化子 ,2 3个克隆有报告基因的表达。排除假阳性后 ,得到 2个阳性克隆 ,它们分别编码Miz 1(myc interactingznfingerprotein 1)和FLNA(actin bindingprotein 2 80 )。结论　ECRG 1基因编码蛋白在酵母中可特异性的结合Miz 1和FLNA ,提示ECRG 1可能通过与MIZ 1、FLNA相互作用参与调控细胞周期的运行。     

重组小鼠凝血因子Ⅶ-pPIC9K表达载体的构建及其在毕赤酵母中的表达

目的:构建去除凝血功能，但保留TF亲和力的rmFⅦ-pPIC9K表达载体并用毕赤酵母表达目的蛋白。方法：通过RTPCR自小鼠肝脏获得FⅦcDNA，对其进行定点突变后连入pPIC9K质粒，电击转化Gs115酵母细胞，经G418筛选、BMGY/BMMY小量摇瓶培养表达目的蛋白，并进行初步的凝血、结合活性鉴定。结果： 成功构建了3种rmFⅦpPIC9K表达载体（M1：LCmFⅦpPIC9K；M2：K341AmFⅦpPIC9K；M3：QEAmFⅦpPIC9K），并通过酵母表达获得相应蛋白，经初步活性鉴定其中两种符合设计目的。     

人ENO1(Enolase-α)基因的原核表达、蛋白纯化及多克隆抗体的制备

目的:构建人ENO1(human Enolase-α)基因的原核表达质粒,诱导重组蛋白的表达,利用纯化后的蛋白制备具有活性的ENO1多克隆抗体.方法:用PCR方法从胃癌MKN45细胞全基因组中扩增出目的基因ENO1,将目的基因和原核表达载体pET30a(+)分别双酶切,回收酶切产物并用T4连接酶连接,获得重组质粒pET30a(+)-ENO1.将重组质粒转入大肠埃希菌菌株BL21,经异丙基-β-D-硫代半乳糖苷(IPTG)诱导表达,用Ni-NTA亲和层析柱纯化,利用纯化的ENO1活性蛋白作为抗原免疫家兔,制备抗血清多克隆抗体,并用Western blot检测其特异性.结果:目的基因与原核表达载体经双酶切鉴定所切下的片段大小与理论值相符,测序结果表明重组人ENO1基因序列与NCBI(NM_001428.3)公布序列一致.经SDS-PAGE分析,结果显示重组蛋白的分子量约在47kDa,条带单一,无杂带出现,主要以可溶性形式存在.Western blot证实多克隆抗体制备成功.结论:成功表达、纯化了ENO1融合蛋白,制备了具有高特异性的多克隆抗体,为进一步肿瘤疫苗的研制和肿瘤标志物快速诊断的研究奠定基础.     

癌-睾丸抗原GAGE-1基因的重组、表达及纯化

目的 为进一步研究临床应用癌-睾丸抗原GAGE-1诱导特异性抗肿瘤免疫反应,对GAGE-1基因进行克隆、体外原核重组表达及蛋白分离纯化。方法 运用RT-PCR技术从人QGY-7701肝癌细胞株中扩增GAGE-1基因片段,插入原核表达载体pGEX-6p-1中,构建重组表达质粒pGEX-6p-1-GAGE-1,并导入大肠杆菌BL21,IPTG诱导目的蛋白表达;经包涵体透析复性及GST柱亲和层析纯化目的蛋白,SDS-PAGE电泳分析鉴定。结果 扩增得到GAGE-1基因5’端251 bp片段,与GeneBank公布的序列一致,构建的PGEX-6p-1-GAGE-1原核表达质粒经IPTG诱导,在大肠杆菌中表达分子量约35.7 kD的GST-GAGE-1融合蛋白,纯化后蛋白纯度为90%以上。结论 成功构建PGEX-6p-1-GAGE-1重组表达质粒,并成功表达纯化了GST-GAGE-1融合蛋白,为进一步深入研究GAGE蛋白奠定了基础。     

巨噬细胞激活剂Polytuftsin在毕赤酵母中的表达及其活性检测

目的 利用毕赤酵母表达系统分泌表达巨噬细胞激活剂Polytufisin.方法 化学法将编码Polytuftsin蛋白的重组质粒转入毕赤酵母菌中,甲醇诱导阳性转化子分泌表达Polytuftsin目的 蛋白;分别于体内外水平上检测纯化后的Polytuftsin对巨噬细胞功能的影响.结果 经SDS-PAGE、PCR法验证该Polytuftsin重组蛋白是正确的目的 产物,相对分子质量约为20×103;该重组蛋白能够体外刺激巨噬细胞分泌NO、TNF-α因子;提高巨噬细胞杀死L1210白血病细胞的能力,最大杀伤率达到40%;经小鼠白血病模型治疗实验发现:给予Polytufisin后小鼠出瘤时间延迟,小鼠生存期延长,平均达到21 d.结论 所得到的Polymftsin重组蛋白可激活巨噬细胞,发挥抗肿瘤作用.     

Expression and Characterization of the Recombinant Human FLT-3 Ligand Extracellular Domain in Pichia Pastoris

T he FLT-3 ligand (fms-like tyrosine kinase receptor-3 ligand, FL) is a recently described growth factor affecting early hematopoiet- ic progenitor cells. The FL plays a key role in the growth and differen-tiation of primitive hematopoietic cells. FL prom…     

胃癌中B7-H4和B7-H3的表达及薏苡仁酯对表达的影响

目的：探讨共刺激分子B7-H4和B7-H3在胃癌中的表达,以及薏苡仁酯对这两种分子表达的影响。方法：应用免疫组织化学染色检测胃癌组织中B7-H4蛋白的表达,MTT法检测薏苡仁酯对胃癌细胞株BGC-823的生长抑制效应,RT-PCR检测胃癌组织、胃癌细胞株BGC-823中B7-H4mRNA及B7-H3mRNA的表达,Western Blot检测细胞的B7-H4蛋白及B7-H3蛋白的表达。结果：B7-H4蛋白在80例胃癌组织中有60例阳性表达,阳性率75%。B7-H4蛋白的表达与患者性别、年龄、组织类型、肿瘤大小、淋巴结转移、病理分期、浸润深度无关（P〉0.05）。在20例胃癌组织中,B7-H4mRNA表达明显高于癌旁正常组织,B7-H3mRNA表达明显低于癌旁正常组织（P〈0.01）。薏苡仁酯可抑制胃癌细胞株BGC-823的生长,呈时间-剂量依赖性,并下调B7-H4 mRNA及蛋白的表达,上调B7-H3mRNA及蛋白的表达（P〈0.01）。结论：B7-H4和B7-H3在胃癌异常的表达,可能是肿瘤免疫逃逸的原因之一;薏苡仁酯可影响胃癌细胞B7-H4、B7-H3的表达。     

Expression and Characterization of the Recombinant Human FLT-3 Ligand Extracellular Domain in Pichia Pastors

OBJECTIVE The FLT-3 ligand （fms-like tyrosine kinase receptor-3 ligand, FL） is a recently described growth factor affecting early hematopoietic progenitor cells. The FL plays a key role in the growth and differentiation of primitive hematopoietic cells. To yield a high-level of recombinant human FL protein, a recembinant Pichia Pastoris （P. pastoris）strain was constructed. METHODS An artificial expression frame, with the same encoding protein sequence for the FL extracellular domain cDNA, was synthesized by using favored genetic codons of P. pastoris. P. pastoris strain KM71 cells were transformed with the endonuclease Bgl II linearized recombined plasmid, pPIC9K-FL. The plasmid then was linerized in the 5＇AOX1 site and integrated into the yeast KM71 genome. KM71 was transformed with pPIC9K plasmids as a control for the production of recombinant protein. Southern blotting and Northern blotting tests were used to screen the genotype of the recombined strain. Biological activity was demonstrated in vitro with culturing of CD34＋cells. RESULTS The recombinant human FL protein expressed into the yeast culture supertant was identified on the basis of its molecular weight and Western blotting analysis. Numerous bands were observed in the 10-100 kDa molecular mass range. SDS-PAGE showed that the expressed product, a 20 kDa protein, was secreted into the medium in the form of a soluble molecule. Western-blot analyses showed good antigenicity and specificity against polyclonal antibodies. A sharp band and a smeared band were observed at a molecular mass of approximately 20 kDa by Western blotting. The recombinant human FL protein was the major protein component observed in the culture supernatant. The highest yield （108 mg/L） was obtained when expression was induced with 0.5% methanol for 96 h. Deglycosylation with PNGase F resulted in a decrease in apparent molecular mass from 20 kDa to 18kDa forming three bands all of which were also detected by rabbit anti-FL antibodies, Culturing of CD34＋ cells in the presence of KM71pPIC9K-FL over 7 days increased 2.9 fold, while in the control group they increased only 1,5 fold. The biological assay showed that the expressed product could stimulate the proliferation of CD34＋ hematopoietic cells, CONCLUSION We demonstrated that human FL was secreted into the culture supernatant from P. pastoris, and that this yeast strain was a preferred host for recombinant human FL gene expression. This recombinant strain can provide a convenient process for pharmaceutical application.     

协同刺激分子B7-H3在结肠癌细胞株中的表达水平及其分布特征

目的研究协同刺激分子B7-H3在结肠癌细胞株中的表达及其细胞内亚细胞结构的分布特征。方法分别采用Real-time PCR、Western Blot方法检测B7-H3在三株结肠癌细胞SW620、SW480、DLD-1中mRNA和蛋白质的表达水平;激光共聚焦显微镜观察B7-H3分子在三株结肠癌细胞中的亚细胞定位。结果 SW620、SW480、DLD-1 Real-time PCR的B7-H3 mRNA△Ct值分别为21.11±0.07、21.18±0.39、21.45±0.18,F=1.3497,P=0.309;Western Blot检测B7-H3蛋白的表达水平无明显差别;B7-H3分子细胞核内的表达比例分别为0.462±0.07、0.329±0.039、0.411±0.025。SW480细胞B7H3核内分布比例与另两株细胞有明显差异(P<0.05)。结论不同结肠癌细胞株中B7-H3 mRNA与蛋白的表达水平无明显差异,细胞核内有部分B7-H3分子表达,且不同细胞株之间B7-H3的核内表达有一定差异。     

B7-H1 and B7-H3 are independent predictors of poor prognosis in patients with non-small cell lung cancer

B7-H1 and B7-H3, two members of the B7 family that are thought to regulate T-cell activation, are expressed in human non-small cell lung cancer (NSCLC). However, their prognostic significance is poorly understood. In the present study we reported that B7-H1 and B7-H3 were expressed in 96/128 (72.7%) and 89/128 (69.5%) samples, respectively. B7-H1 and B7-H3 expression and the number of infiltrating T-cell intracellular antigen-1+ and interferon-γ+ cells in NSCLC tissues were significantly higher than those in the adjacent tissues (p<0.01). High B7-H1 or B7-H3 expression was associated with lymph node metastasis and TNM stage (p<0.05, respectively). Sex, TNM stage, B7-H1, B7-H3, and T-cell intracellular antigen-1 expression remained significant prognostic factors after adjusting for other prognostic factors in a multivariate Cox proportional hazards regression model. In vitro studies revealed that knockdown of B7-H3 on tumor cells enhanced T-cell growth and interferon-γ secretion when stimulated by anti-CD3 and anti-CD28 monoclonal antibodies. Interferon-γ reduced CXCR4 expression on cancer cells and inhibited the CXCL12-induced cell migration. B7-H1 and B7-H3 are independent predictors of poorer survival in patients with NSCLC. Interference of the signal pathways of these negative regulatory molecules might be a new strategy for treating NSCLC.     

B7-H3对小鼠Lewis肺癌细胞生长的影响

目的观察B7-H3对Lewis肺癌(LLC)细胞生长的影响并探讨其作用机制。方法采用40只C57BL/6小鼠,右腋下接种Lewis肺癌细胞悬液,建立皮下种植瘤模型,随机分为4组,在瘤体附近皮下围绕瘤体分别注射多西他赛、B7-H3及多西他赛+B7-H3,以注射空质粒作为对照。注射后第1、3、7、14天测量肿瘤的大小,计算肿瘤的体积;采用免疫组织化学及Western blot检测瘤组织中B7-H3的表达;采用ELISA检测小鼠血清IL-12的水平。结果多西他赛和B7-H3均能分别抑制肿瘤的生长,两者联合则抑制作用增强,多西他赛组、B7-H3组及多西他赛+B7-H3组的抑瘤率分别为32.98%、28.59%和4595%,上述处理后肿瘤细胞凋亡率均比对照组明显提高(P<0.01);B7-H3组及多西他赛+B7-H3组肿瘤组织中B7-H3的表达下调,但差异无统计学意义(P>0.05);小鼠血清中IL-12的表达在B7-H3组及多西他赛+B7-H3组均较对照组水平升高(P<0.05)。结论 B7-H3能抑制小鼠Lewis肺癌细胞的生长,其机制可能与通过IL-12诱导激活细胞毒性T细胞而产生抗肿瘤免疫应答有关。     

沉默B7-H3基因表达对人肝癌细胞侵袭能力的影响

目的 研究靶向沉默B7-H3基因表达对HepG2细胞侵袭能力的影响及可能机制。方法 设计针对B7-H3基因的shRNA沉默质粒,转染HepG2细胞,下调B7-H3的表达。划痕修复实验检测转染前后HepG2细胞移行能力的变化,Transwell实验检测基因沉默对细胞侵袭能力的影响,MST-1法和ELISA凋亡试剂盒分别检测细胞增殖和凋亡水平变化。通过Western blot实验和明胶酶谱实验检测侵袭相关分子MMP-2、MMP-9的表达和活性变化。结果 成功构建B7-H3 shRNA沉默质粒并转染HepG2细胞。与对照质粒转染组和未转染组比较,沉默B7-H3基因表达后,B7-H3 shRNA转染组HepG2细胞的移行（24 h: P=0.001; 48 h: P<0.001; 72 h: P<0.001）和侵袭（P<0.001）能力受到显著抑制,细胞的增殖和凋亡水平没有明显变化（P>0.05）。MMP-2、MMP-9的蛋白表达（MMP-2: P<0.001; MMP-9: P=0.007）和活性（MMP-2: P<0.001; MMP-9: P<0.001）均显著下降。结论 通过B7-H3 shRNA沉默质粒靶向沉默B7-H3的基因表达能抑制HepG2细胞的侵袭能力,其机制可能与抑制MMP-2、MMP-9的表达和活性有关。     

Tumor B7-H1 and B7-H3 Expression in Squamous Cell Carcinoma of the Lung

BackgroundPulmonary squamous cell carcinoma has a poor prognosis, and new therapeutic targets are needed. The aberrant expression of the immunomodulatory proteins B7-H1 and B7-H3 by malignant cells may contribute to tumoral immune evasion. Data about the expression of these proteins by squamous cell carcinoma of the lung are limited.Materials and MethodsImmunohistochemistry for B7-H1 and B7-H3 was performed on 214 resected pulmonary squamous cell carcinoma specimens.ResultsAt the last follow-up, 171 of 214 (80%) of patients were deceased (median survival time, 3.76 years). Forty-two (19.6%) of 214 cases showed positivity with B7-H1, with a range of 5% to 60% of cells that stained positively. A total of 189 (88.3%) of 214 cases showed positivity with B7-H3, with a range of 5% to 80% of cells staining positively. By using multivariate analysis, no degree of B7-H1 or B7-H3 positivity was significantly associated with patient outcome.ConclusionsAlthough B7-H1 and B7-H3 are not of independent prognostic value, they are commonly expressed on a subset of tumor cells in pulmonary squamous cell carcinomas. Known interaction of the B7-H proteins with cytotoxic T-lymphocyte antigen-4 may make them attractive candidate biomarkers for response to immunomodulatory therapeutics, eg, ipilimumab, and warrants further study.     

Roles of coinhibitory molecules B7-H3 and B7-H4 in esophageal squamous cell carcinoma

The coinhibitory molecules, B7-H3 and B7-H4, have shown negative regulation in T cell activation and tumor-associated macrophage (TAM) polarization in tumor-specific immunity. Here, we investigated the expression of B7-H3 and B7-H4 in human and murine esophageal squamous cell carcinoma (ESCC) tissues to define their clinical significance and mechanism in a tumor microenvironment. In the present study, B7-H3 and B7-H4 were expressed in 90.6 and 92.7 % samples, respectively. High B7-H3 and B7-H4 expression was associated with advanced TNM stage and lymph node metastasis (p?<?0.05, respectively). Patients with both B7-H3 and B7-H4 high-expressed tumors had the poorest prognosis (26.7 months), whereas those with both low-expressed tumors had the best survival (56.7 months). B7-H3 and B7-H4 expression were inclined to be positively related to the infiltration intensity of Treg cells and TAMs (p?<?0.05, respectively), and B7-H3 expression is negatively associated with the intensity of CD8⁺ T cells (p?<?0.05). In 4-nitroquinoline 1-oxide (4-NQO)-induced murine models, high B7-H3 expression could only be detected at carcinoma stage, but abnormal B7-H4 expression appeared a little earlier at dysplasia stage. In vitro studies revealed that knockdown of B7-H3 on tumor cells suppressed ESCC cell migration and invasion, while knockdown of B7-H4 could inhibit ESCC cell growth. Overall, B7-H3 and B7-H4 are involved in ESCC progression and development and their coexpression could be valuable prognostic indicators. Interference of these negative regulatory molecules might be a new strategy for treating ESCC.