CONSTRUCTION AND EXPRESSION OF THE REPLICATION-DEFI-CIENT ADENONIRUS VECTOR OF HUMAN GM-CSF

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Construction and characterization of a recombinant adenoviral vector expressing human interleukin-12.

Interleukin-12 (IL-12) is a 70-kDa heterodimeric cytokine composed of a 35-kDa subunit (p35) and a 40-kDa subunit (p40). We have demonstrated previously that intratumoral delivery of a recombinant adenoviral vector expressing the mouse IL-12 gene significantly prolongs the survival time of mice with metastatic colon carcinoma in the liver. We now report the molecular cloning of cDNA for both subunits of human IL-12 (hIL-12) in a recombinant adenoviral vector in which the p40 and p35 subunits are linked and coexpressed using the encephalomyocarditis virus internal ribosome entry site. The recombinant adenoviral vector was used to transduce human tumor cell lines, and the presence of hIL-12 in the conditioned media was illustrated by enzyme-linked immunosorbent assay. The biological activity of hIL-12 in the conditioned media was also demonstrated in vitro through its ability to induce interferon-gamma production from peripheral blood mononuclear cells (PBMCs), to stimulate PBMC proliferation, and to enhance natural killer activity from normal human PBMCs to lyse natural killer-sensitive K562 target cells. The results of these studies support the application of this recombinant adenoviral vector construct as an efficient gene delivery vehicle in phase I/II clinical studies of hIL-12 gene therapy for cancer.     

Expression and immunogenicity in rats of recombinant adenovirus 5 DNA plasmids and vaccinia virus containing the HTLV-I-env gene

The complete human T-cell leukemia virus type I (HTLV-I) env gene was inserted into an expression cassette containing the adenovirus 5 major late promoter (Ad5-MLP). Recombinant Ad5-HTLV-I-env was obtained by homologous recombination in 293 cells simultaneously transfected by the expression cassette and the genomic DNA of Ad5. In vitro expression of the HTLV-I-env gene in the recombinant vector was detected by immunofluorescence and Western blotting. Functional expression of HTLV-I-env was confirmed by syncitium formation specifically in HeLa cells infected with Ad5-HTLV-I-env. Two immunization regimens against HTLV-I were tested in WKY and Fischer F-344 rats. The first involved WKY rats primed with Ad5-HTLV-I-env or naked DNA plasmids containing the HTLV-I-env gene and boosted with Ad5 containing the HTLV-I-env gp46 gene or with baculovirusderived recombinant gp46. No antibody against HTLV-I was detected, while HTLV-I-specific cytotoxic T lymphocytes were recovered from all immunized groups but not from controls. The second approach involved Fischer F-344 rats primed and boosted with recombinant vaccinia virus containing the HTLV-I-env gene. Such rats developed antibodies against the HTLV-I env gp21 and gp46 (non-neutralizing). After challenge with human HTLV-I-producing cells (MT-2), both immunization regimens were found to induce partial protection. Int. J. Cancer 71:300–307, 1997. © 1997 Wiley-Liss, Inc.     

人p27kip1重组腺病毒载体的构建及其介导的p27kip1表达

目的　研究外源性p2 7kip1基因对细胞周期及细胞增殖的影响。方法　构建CMV启动子转录调控的含人p2 7kip1cDNA的E1区替代的腺病毒载体pAxlcw .CIhp2 7kip1,与经EcoT2 2 1酶切的Ad5腺病毒DNA -末端肽复合物共转染 2 93细胞 ,制备p2 7kip1重组腺病毒 ,在体外转染HeLa细胞 ,Westernblot、FACS及MTT检测分析外源性p2 7kip1蛋白在细胞内的表达 ,以及对细胞周期及细胞增殖的影响。结果　获得含人p2 7kip1cDNA的重组腺病毒 ,滴度为 1.7× 10 9pfu/ml。体外转染HeLa细胞2 4h后 ,p2 7kip1蛋白在p2 7kip1转染后的HeLa细胞中高表达 ;FACS检测表明 ,p2 7kip1和LacZ重组腺病毒转染后的HeLa细胞 ,经 10 %血清刺激后处于G1期的细胞分别为 89.93%和 5 9.84% ;MTT法检测表明 ,人p2 7kip1重组腺病毒转染后的HeLa细胞经 2 0 %血清刺激后 ,48及 72h的A值均低于LacZ重组腺病毒转染后的HeLa细胞 (P <0 .0 1)。结论　本研究中所制备的p2 7kip1重组腺病毒能有效介导外源性p2 7kip1基因在体外转染HeLa细胞并高表达p2 7kip1,抑制细胞由G1期向S期过渡 ,从而抑制细胞增殖 ,为进一步研究p2 7kip1基因治疗奠定了基础。     

Enhanced antitumor efficacy of a novel fiber chimeric oncolytic adenovirus expressing p53 on hepatocellular carcinoma

Oncolytic adenoviruses may offer a new treatment option and improve the prognosis for patients with hepatocellular carcinoma (HCC). However, the antitumor efficacy of oncolytic adenoviruses on HCC cells is compromised due to low expression of the adenovirus serotype 5 (Ad5) receptor on the target cells. In this study we showed that all HCC cell lines and clinical samples expressed high level of CD46, the receptor for Adenovirus 35 (Ad35) and constructed new fiber chimeric oncolytic adenoviruses with or without a p53 gene expression cassette, SG635-p53 and SG635, respectively. These variants were derived from the previously described Ad5 vectors SG600-p53 and SG600 by replacing the Ad5 fiber with a chimeric Ad5/35 fiber. It was found that the 5/35 fiber chimeric adenovirus vector (Ad5/35-EGFP) demonstrated significantly improved transduction in all tested HCC cell lines compared with the Ad5 vector (Ad5-EGFP). The new fiber chimeric oncolytic adenoviruses produced more progeny viruses in HCC cells than did the Ad5-based viruses but replicated weakly in normal fibroblast BJ cells. In addition, SG635-p53 mediated a higher level of transgenic expression than SG600-p53 in Hep3B and Huh7 cells and showed a markedly enhanced antitumor effect on HCC cells in vitro compared with SG635 or SG600-p53 without causing significant cytotoxicity to normal cells. Antitumor activity of SG635-p53 was shown in Hep3B subcutaneous xenograft tumor models following intratumoral injection, resulting in significant inhibition of tumor growth and prolonged survival of animals. Our data suggest that SG635-p53, as a fiber chimeric oncolytic adenovirus in combination with p53 expression, may serve as a novel, promising and safe anticancer agent for the treatment of HCC.     

Transgene amplification and persistence after delivery of retroviral vector and packaging functions with E1/E4-deleted adenoviruses

Adenovirus DNA is rapidly lost in actively dividing cells. In addition, first-generation (E1-defective) vectors trigger a strong cytotoxicity that impairs the duration of transgene expression. To solve these issues, we have developed a chimeric vector system that uses E1/E4 doubly defective adenoviruses for efficient production of infectious retroviral vectors. The retroviral vector sequences and packaging functions were split into two E1/E3/E4-deleted adenoviral vectors: the Moloney murine leukemia virus gag-pol cistron was expressed from the human EF1 alpha (elongation factor) promoter (AdGAG/POL), whereas the thymidine kinase transgene, embedded in a retroviral vector context, and an amphotropic retroviral envelope cassette were included within a second adenovirus (AdTK/ENV). This chimeric vector system was evaluated with a special emphasis on recombinant retrovirus production in vitro, as well as transgene amplification and persistence in vivo. Retrovirus titers of >10(5) infectious units/mL were routinely obtained in W162 cells coinfected with both recombinant adenoviruses. Long-term transgene persistence (up to 3 months) was demonstrated in vitro in two different cell lines coinfected with AdGAG/POL and AdTK/ENV, and correlated with the detection of specific provirus sequences. A 10- to 50-fold transgene amplification also was demonstrated in an in vivo tumor model infected with the Ad/Rt chimeric vector system. The chimeric vector system described herein combines the efficiency of gene delivery by recombinant adenoviruses with the integrative properties of infectious retroviral vectors. This versatile vector system may open up new avenues for efficient production of oncogenic, but also non-oncogenic, retroviruses from cells of non-murine origin.     

Construction of a recombinant adeno-associated virus (rAAV) vector expressing murine interleukin-12 (IL-12)

IL-12 is a heterodimeric cytokine that is known to induce tumor regression and long-term antitumor immunity. Recombinant adeno-associated virus (rAAV) vectors are advantageous for gene therapy in that they lack pathogenicity in humans, infect dividing as well as nondividing cells, and show a broad range of infectivity. We constructed an rAAV vector expressing interleukin-12 (IL-12) for cancer immunotherapy studies in a mouse model by inserting murine IL-12 (mIL-12) p35 and p40 cDNAs into the plasmid pRep4 and inserting the encephalomyocarditis virus internal ribosomal entry site between the p35 and p40 cDNAs. The mIL-12 expression cassette containing the Rous sarcoma virus promoter and a simian virus 40 polyadenylation signal was subcloned into the AAV plasmid p008Sub/NeoR, which contains two AAV inverted terminal repeat sequences and the NeoR gene driven by the thymidine kinase promoter. rAAV virions (10(4) infectious particles/ml) were generated by cotransfection of rAAV-mIL-12 and a helper plasmid (pAAV/Ad) into 293 cells previously infected with adenovirus 5. After infection of D6 fibroblasts with rAAV-mIL-12, G418-resistant clones were isolated. Each of the 1D D6 clones isolated produced up to 5.2 ng/10(6) cells/48 hours of mIL-12 as determined by enzyme-linked immunosorbent assay. Induction of interferon-gamma, enhanced lymphocyte proliferation, and cytotoxicity assays confirmed biologically functional IL-12 production by the vector. This is the first report indicating that an rAAV vector expresses mIL-12, which can be used to model the effects of mIL-12 alone and/or in combination with other antitumor agents.     

Intratumor injection of oncolytic adenovirus expressing HSP70 prolonged survival in melanoma B16 bearing mice by enhanced immune response

Heat shock proteins (HSPs) possess potent antitumor ability to stimulate immune response. We postulated that intratumor injection of oncolytic adenovirus over-expressing HSPs might be able to exert antitumor activity by inducing antitumor immune response in immunocompetent hosts in addition to the oncolytic activity. In this study, two recombinant oncolytic adenoviruses, Ad.CMV.HSP.IRES.E1a and Ad.CMV.IRES.E1a, were constructed with or without the HSP expression cassette. The HSP expression and cytopathic killing effect in mouse B16 melanoma and human PLC/PRF/5 hepatoma cells were measured after in vitro infection of adenoviruses. Survival rate of immunocompetent C57/BL mice was observed following intratumor injection of recombinant adenoviruses in B16 melanoma xenograft models. To detect the evidence of immune responses, hematoxylin and eosin staining and RT-PCR for IFN-gamma expression in tumor tissues were performed. The Ad.CMV.HSP.IRES.E1a induced significantly higher HSP expression level than Ad.CMV.IRES.E1a in both B16 and PLC/ PRF/5 cells. The cytocidal efficacy of Ad.CMV.HSP.IRES.E1a and Ad.CMV.IRES.E1a in PLC/PRF/5 cells was much higher than that in B16 cells, where the two adenoviruses showed similarly very weak oncolytic effect in vitro. However, Ad.CMV.HSP.IRES. E1a improved animal survival rate and exhibited more potent anti-tumor efficiency than Ad.CMV.IRES.E1a in B16 xenograft models. The enhanced efficacy might be mainly attributed to the HSP-mediated immune activity, as evidenced by the up-regulated expression of IFN-gamma and local heavier intratumor inflammatory cell infiltration. These results indicated that the recombinant oncolytic adenovirus over-expressing HSPs possessed powerful in vivo anti-tumor efficacy and might be a valuable approach for cancer immune gene therapy.     

CD47-retargeted oncolytic adenovirus armed with melanoma differentiation-associated gene-7/interleukin-24 suppresses in vivo leukemia cell growth

Our previous studies have suggested that harboring a soluble coxsackie-adenovirus receptor-ligand (sCAR-ligand) fusion protein expression cassette in the viral genome may provide a universal method to redirect oncolytic adenoviruses to various membrane receptors on cancer cells resisting to serotype 5 adenovirus infection. We report here a novel oncolytic adenovirus vector redirected to CD47+ leukemia cells though carrying a sCAR-4N1 expression cassette in the viral genome, forming Ad.4N1, in which 4N1 represents the C-terminal CD47-binding domain of thrombospondin-1. The infection and cytotoxicity of Ad.4N1 in leukemia cells were determined to be mediated by the 4N1-CD47 interaction. Ad.4N1 was further engineered to harbor a gene encoding melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24), forming Ad.4N1-IL24, which replicated dramatically faster than Ad.4N1, and elicited significantly enhanced antileukemia effect in vitro and in a HL60/Luc xenograft mouse model. Our data suggest that Ad.4N1 could act as a novel oncolytic adenovirus vector for CD47+ leukemia targeting gene transfer, and Ad.4N1 harboring anticancer genes may provide novel antileukemia agents.     

5-Fu和α干扰素抗肿瘤血管形成协同效应的实验研究

目的: 研究fat-1基因在人乳腺癌细胞内的表达、功能及其对乳腺癌细胞增殖的影响.方法: 把fat-1 基因插入到腺病毒的穿梭载体中,与骨架载体同源重组,构建腺病毒重组载体 (Ad.GFP.fat1),将通过包装细胞系(293)产生的腺病毒感染人乳腺癌株QMR2细胞.提取细胞的总RNA,以fat-1的反义mRNA 作探针,用Northern Blot检测fat-1 基因在人乳腺癌株QMR2细胞内的表达.流式细胞仪分析n-3脂肪酸脱氢酶对人乳腺癌株QMR2细胞增殖的影响.气象色谱仪分析n-3脂肪酸脱氢酶对人乳腺癌株QMR2细胞的n-6 PUFAs/n-3 PUFAs含量影响.结果: fat-1 基因在人乳腺癌株QMR2细胞中能有效异源表达,2 d后检测到fat-1mRNA的条带.fat-1基因抑制了人乳腺癌株QMR2细胞的增殖,降低了20%(P<0.05);同时降低了人乳腺癌株QMR2细胞n-6 PUFAs/n-3 PUFAs含量降低.结论: 腺病毒介导的fat-1 基因能在人乳腺癌株QMR2细胞内有效异源表达,且抑制人乳腺癌株QMR2细胞的增殖.     

人PSMA基因重组腺病毒的构建及其在树突状细胞上的表达

  目的   构建含有人前列腺特异性膜抗原基因（prostate specific membrane antigen,PSMA）的重组腺病毒,并将其感染树突状细胞（dendritic cell,DC）后检测其在DC上的表达。   方法   设计一对含有SfiⅠ酶切位点的PSMA基因上下游引物,以质粒pCMV-SPORT6/PSMA为模板,通过PCR扩增获得PSMA基因序列。片段回收、酶切处理,连接到穿梭质粒pShuttle-CMV-EGFP上,获得重组穿梭质粒pShuttle-EGFP-PSMA。经SfiⅠ酶切、PCR及插入片段测序鉴定正确后,将其用I-CeuI和I-SceI双酶切处理,转移至pAdxsi载体上,得到pAdxsi-GFP-PSMA病毒质粒,线性化后经HEK293细胞包装成复制缺陷型腺病毒Ad-PSMA-GFP;感染从健康志愿者外周血来源的DC,荧光倒置显微镜下观察绿色荧光蛋白（GFP）的表达,Western blot检测PSMA基因在DC上的表达。   结果   成功构建含有人PSMA基因的重组腺病毒,病毒滴度为2×1010 pfu/mL。构建好的Ad-PSMA-GFP可以在DC上高效和正确地表达。   结论   人PSMA重组腺病毒载体的成功构建及其在DC上的表达,为下一步研究奠定了基础。      

采用GatewayTM系统构建人Rb94基因重组腺病毒载体

 目的 采用Gateway^TM技术构建人Rb94基因重组腺病毒载体(Ad-hRb94)。方法 从人类胚胎中提取总RNA,经反转录得到目的cDNA,PCR扩增Rb94目的基因片段。设计含有attB侧翼序列的引物,用于重组片段的PCR扩增,在BP重组酶的作用下,将含attB位点的PCR产物与受体载体pDONR^TM221发生重组反应,产生入门克隆。在LR重组酶作用下,将入门克隆与带attR1、attR2位点的目的载体 Ad／CMV／V5-DEST体外重组形成表达克隆 Ad-hRb94。经PCR和测序鉴定,将 Ad-hRb94线性化后转入 293A细胞进行病毒的包装、扩增及病毒滴度测定。结果 经PCR和测序证实目的基因Rb94片段按正确方向重组入目的载体中,带Rb94基因的目的载体在 293A细胞中包装成功,获得高滴度的病毒颗粒,滴度为9.41×1010pfu／ml。结论本实验利用Gateway^TM技术成功构建了Ad-hRb94,为进一步进行肿瘤基因治疗研究奠定了实验基础。     

HPV-16 E6 siRNA与hIL-24基因联合诱导人宫颈癌Ca Ski细胞的凋亡

目的：观察HPV-16 E6 siRNA与hIL-24基因体外共转染，联合诱导人宫颈癌CaSki细胞凋亡的效应。方法：HPV-16 E6 siRNA与hIL-24基因的质粒载体分别以单独或联合的方式转染入宫颈癌CaSki细胞，随后利用RT—PCR技术检测细胞中HPV-16E6癌基因的mRNA水平变化；Western blot分析细胞中抑癌蛋白p53水平的变化；流式细胞技术分析细胞凋亡情况。结果：经HPV-16 E6 siRNA和hIL-24转染后细胞后HPVE6癌基因的mRNA水平均下降，其中联合转染组显著下降（P〈0，05）；抑癌蛋白p53水平均增高，其中联合转染组显著增高，细胞凋亡率均升高，其中联合转染组显著升高（P〈0．05）。结论：HPV-16 E6siRNA与hIL-24基因分别转染宫颈癌CaSki细胞后，均能抑制CaSki细胞中HPV-16E6癌基因的表达，使抑癌蛋白p53恢复活性，诱导宫颈癌CaSki细胞凋亡；两者联合别具有协同效应，能显著提高肿瘤细胞凋亡率。     

Transcription-targeted gene therapy for androgen-independent prostate cancer

The Escherichia coli enzyme (purine nucleoside phosphorylase, PNP) gene is delivered directly into PC3 tumors by one injection of replication-deficient human type-5 adenovirus (Ad5). Expressed PNP converts the systemically administered prodrug, 6MPDR, to a toxic purine, 6MP, causing cell death. We sought to increase the specificity of recombinant Ad vectors by controlling PNP expression with the promoter region from the androgen-dependent, prostate-specific rat probasin (Pb) gene. To increase its activity, the promoter was combined with the SV40 enhancer (SVPb). Cell lines were transfected with plasmids containing both a reporter gene, under SVPb control, and a reference gene cassette to allow normalization of expression levels. Plasmids expressed approximately 20-fold more reporter in prostate cancer than in other cells, but surprisingly, the SVPb element was both androgen-independent and retained substantial prostate specificity. Killing by Ad5-SVPb-PNP vector of cell lines cultured with 6MPDR for 6 days was 5- to 10-fold greater in prostate cancer than in liver or lung cells. In vivo, a single intratumoral injection of Ad5-SVPb-PNP (4 x 10(8) pfu), followed by 6MPDR administration twice daily for 6 days, significantly suppressed the growth of human prostate tumors in nude mice and increased their survival compared to control animals. Thus, the androgen-independent, prostate-targeting Ad5 vector reduces human prostate cancer growth significantly in vitro and in vivo. This first example of an androgen-independent vector points the way toward treatment of emerging androgen-independent prostate cancer in conjunction with hormone ablation therapy at a time when the tumor burden is low.     

CD123 targeting oncolytic adenoviruses suppress acute myeloid leukemia cell proliferation in vitro and in vivo

We report here a novel strategy to redirect oncolytic adenoviruses to CD123 by carry a soluble coxsackie-adenovirus receptor (sCAR)-IL3 expression cassette in the viral genome to form Ad.IL3, which sustainably infected acute myeloid leukemia (AML) cells through CD123. Ad.IL3 was further engineered to harbor gene encoding manganese superoxide dismutase (MnSOD) or mannose-binding plant lectin Pinellia pedatisecta agglutinin (PPA), forming Ad.IL3-MnSOD and Ad.IL3-PPA. As compared with Ad.IL3 or Ad.sp-E1A control, Ad.IL3-MnSOD and Ad.IL3-PPA significantly suppressed in vitro proliferation of HL60 and KG-1 cells. Elevated apoptosis was detected in HL60 and KG-1 cells treated with either Ad.IL3-MnSOD or Ad.IL3-PPA. The caspase-9–caspase-7 pathway was determined to be activated by Ad.IL3-MnSOD as well as by Ad.IL3-PPA in HL60 cells. In an HL60/Luc xenograft nonobese diabetic/severe-combined immunodeficiency mice model, Ad.IL3-MnSOD and Ad.IL3-PPA suppressed cancer cell growth as compared with Ad.IL3. A significant difference of cancer cell burden was detected between Ad.IL3 and Ad.IL3-PPA groups at day 9 after treatment. Furthermore, Ad.IL3-MnSOD significantly prolonged mouse survival as compared with Ad.sp-E1A. These findings demonstrated that Ad.IL3-gene could serve as a novel agent for AML therapy. Harboring sCAR-ligand expression cassette in the viral genome may provide a universal method to redirect oncolytic adenoviruses to various membrane receptors on cancer cells resisting serotype 5 adenovirus infection.     

Human adenovirus type 35 vector for gene therapy of brain cancer: improved transduction and bypass of pre-existing anti-vector immunity in cancer patients

Clinical trials in malignant glioma have demonstrated excellent safety of recombinant adenovirus type 5 (Ad5) but lack of convincing efficacy. The overall low expression levels of the Coxsackie and Adenovirus receptor and the presence of high anti-Ad5-neutralizing antibody (NAb) titers in the human population are considered detrimental for consistency of clinical results. To identify an adenoviral vector better suited to infect primary glioma cells, we tested a library of fiber-chimeric Ad5-based adenoviral vectors on 12 fresh human glioma cell suspensions. Significantly improved marker gene expression was obtained with several Ad5-chimeric vectors, predominantly vectors carrying fiber molecules derived from B-group viruses (Ad11, Ad16, Ad35 and Ad50). We next tested Ad35 sero prevalence in sera derived from 90 Dutch cancer patients including 30 glioma patients and investigated the transduction efficiency of this vector in glioma cell suspensions. Our results demonstrate that the sero prevalence and the titers of NAb against Ad35 are significantly lower than against Ad5. Also, recombinant Ad35 has significantly increased ability to transfer a gene to primary glioma cells compared to Ad5. We thus conclude that Ad35 represents an interesting candidate vector for gene therapy of malignant glioma.     

改变细胞膜脂肪酸组成防治大肠癌的基因治疗研究*

目的:利用脂肪酸去饱和酶基因fat- 1 改变细胞膜脂肪酸组成,进行大肠癌的基因治疗研究。方法:将fat- 1 基因插入腺病毒载体中,与骨架载体同源重组,构建腺病毒重组载体（Ad-GFP-fat1）,通过包装细胞系（293）产生的腺病毒,感染人大肠癌株HT- 29细胞。提取细胞的总RNA,以fat- 1 基因的反义mRNA 作探针,用Northern Blot检测fat- 1 基因在HT- 29细胞内的表达。以流式细胞仪对HT- 29细胞G0/G1 期、S 期、G2/M期所占比例进行检测,分析fat- 1 基因对HT- 29细胞增殖和凋亡的影响。以气相色谱分析仪分析fat- 1 基因对HT- 29细胞细胞膜n-6 PUFAs 和n-3 PUFAs 含量及n-6/n- 3PUFAs 比例的影响。将HT- 29细胞皮下接种于裸鼠右前肢腋下,建立裸鼠HT- 29大肠癌细胞皮下移植瘤模型。成瘤后进行治疗实验,经连续5 次治疗,于最后一次治疗后第3 天处死小鼠,取肿瘤称重。分析fat- 1 基因裸鼠体内抗肿瘤效果。结果:通过基因重组技术,得到高滴度的含fat- 1 基因的重组病毒;腺病毒介导的fat- 1 基因能够在HT- 29细胞中有效表达;fat- 1 基因的表达可降低HT- 29细胞膜n-6/n- 3PUFAs 的比例,有效抑制HT- 29细胞增殖,促进细胞凋亡并能抑制裸鼠移植瘤的发展。结论:fat- 1 基因的表达,可抑制HT- 29细胞的体内外增殖并诱导细胞凋亡,在大肠癌基因治疗中可能具有良好利用价值。      

人LY6D基因真核表达载体的构建及蛋白的表达和定位

目的:构建人LY6D真核表达载体并证实融合蛋白在细胞内的表达和定位。方法:提取HEK293T细胞的mRNA，反转录为cDNA。PCR扩增LY6D基因的CDS序列，并将其亚克隆至pEGFP-C1表达载体中。进一步将构建的重组质粒进行酶切和测序鉴定，并转染到工具细胞HEK293T中，提取细胞总蛋白进行Western blot检测。然后利用激光扫描共聚焦显微镜观察LY6D在HEK293T细胞内的定位，最后Q-PCR检测过表达LY6D真核表达载体影响EMT关键基因的表达。结果:LY6D基因cDNA的编码区序列克隆到了真核表达载体pEGFP-C1中，酶切鉴定片断为387 bp，并进一步测序成功。Western blot检测到了pEGFP-LY6D融合蛋白的表达，分子量约为41 kDa。pEGFP-LY6D融合蛋白在HEK293T细胞中主要定位于细胞膜和细胞质。过表达LY6D真核表达载体减少E-cadherin的表达。结论:成功构建了LY6D基因cDNA的CDS序列的真核表达载体，pEGFP-LY6D蛋白在HEK293T细胞中主要定位于细胞膜和细胞质，LY6D过表达可以降低E-cadherin的表达。     

真核表达p27构建胃癌顺铂耐药细胞模型的研究

目的:构建p27真核表达载体并导入胃癌SGC-7901细胞获得稳定表达p27的稳定细胞株,以研究p27在胃癌SGC-7901细胞顺铂耐药中所发挥的功能。方法:以乳腺文库为模板,PCR扩增出p27编码区,并将其连接到pCDNA 3.0-Flag载体上,转染293T细胞后分别用定量PCR和Western blot检测其表达情况,并通过Western blot检测SGC-7901细胞过表达Flag-p27稳定细胞株是否构建成功。通过CCK-8药物敏感性实验检测p27在胃癌细胞顺铂耐药中所发挥的功能。结果:双酶切和测序结果表明,pCDNA 3.0-Flag-p27构建成功,并在293T中成功表达,胃癌SGC-7901细胞过表达Flag-p27细胞株建立成功,通过耐药曲线表明过表达p27可以引起SGC-7901细胞顺铂耐药。结论:成功构建了带Flag标签的p27真核表达载体,为进一步研究p27在胃癌耐药中的功能奠定了基础。