腺病毒载体的研究进展

目的由于腺病毒载体转导目的基因具有高效率、低致病性、高滴度以及在体内不整合入宿主细胞染色体等优点,已被认为是最有效的转基因载体之一,并广泛应用于人类基因治疗。但是腺病毒载体还存在一些不足,如具有一定的免疫原性和毒性等,尚有待进一步解决。随着腺病毒载体研究的进展,新的载体系统必将在基因治疗中发挥更重要的作用。本文对腺病毒载体的研究进展作一综述。     

重组hTRAIL腺病毒载体的构建及鉴定

目的构建表达hTRAIL基因的重组腺病毒载体。方法以重组质粒pThioHisA-TRAIL中提取的TRAIL基因为模板,采用PCR法扩增基因片段。将扩增的基因片段插入穿梭质粒pShuttle-CMV,并转化大肠肝菌DH5α。筛选重组质粒pShuttle-CMV-TRAIL,电转化已转化了pAdEasy-1的BJ5183细胞。筛选重组腺病毒质粒pAdEasy-TRAIL,用Lipofectamine转染293细胞,制备携带人全长TRAIL基因的重组复制缺陷型腺病毒(Ad-TRAIL)。氯化铯密度梯度离心法纯化Ad-TRAIL病毒颗粒,并测定病毒滴度。采用RT-PCR法检测TRAIL基因在293细胞中的转录。以Ad-TRAIL转染YTMLC细胞,采用免疫荧光法和流式细胞术检测TRAIL基因的表达。结果纯化后的Ad-TRAIL病毒颗粒数为2.77×1012VP/ml,感染性滴度为109.5(3.2×109)CCID50/ml。经RT-PCR扩增出约843bp的基因片段,与目的片段大小一致。流式细胞术和免疫荧光法均检测到TRAIL在YTMLC细胞中的表达,表达产物主要存在于细胞质中。结论已成功构建了表达hTRAIL重组腺病毒载体,为肿瘤的基因治疗提供了依据。     

重组HIV-1腺病毒载体活疫苗的冻干保护剂研究

目的研制重组HIV-1腺病毒载体活疫苗的冻干保护剂。方法在重组HIV-1腺病毒载体活疫苗中加入不同配比的保护剂,在适宜条件下制备成冻干剂型。根据冻干后外观、病毒滴度和热稳定性试验等结果,筛选出冻干保护剂的最适配方。结果以人血白蛋白、海藻糖、甘露醇、右旋糖苷和蔗糖等成分按比例配伍制备的保护剂,对重组HIV-1腺病毒载体活疫苗显示了较好的保护作用。冻干前后疫苗病毒感染性滴度下降在0.17LogCC ID50/ml以内;37℃放置1周,滴度下降0.3LogCC ID50/ml左右;37℃放置3周后,滴度下降约为0.6LogCC ID50/ml。而无保护剂的液体疫苗对照于37℃放置1周,滴度下降近2.5个LogCC ID50/ml。结论以人血白蛋白、海藻糖、甘露醇、右旋糖苷和蔗糖等配伍而制备的保护剂效果较好。     

重组腺相关病毒载体在基因治疗中的应用

重组腺相关病毒(rAAV)载体具有安全性好、免疫原性低、能感染分裂细胞和非分裂细胞、能介导基因长期稳定表达等优点。因此,作为一种基因导入系统,rAAV载体在基因治疗的研究和开发中越来越受到关注。本文就rAAV载体在基因治疗中的应用作一综述。     

重组BCG疫苗的研究进展

卡介苗(bacille calmette-guerin,BCG)具有安全性高、热稳定性好等优势,以其为载体可构建重组卡介苗(recombinant bacille calmette-guerin,rBCG),rBCG疫苗构建技术已被广泛应用于开发疫苗,以抵抗包括结核在内的各种感染性疾病。本文主要对rBCG疫苗在预防和治疗肿瘤、抵抗细菌、病毒及寄生虫感染方面的研究进展及其应用前景作一综述。     

重组人-p53腺病毒注射液

重组人-p53腺病毒注射液是治疗恶性肿瘤药物中的新品,可以有效地将治病的p53基因转入肿瘤细胞内,特异地引起肿瘤细胞程序性死亡,或者使肿瘤细胞处于严重冬眠状态,而对正常细胞无害。     

重组腺病毒载体pAd-4-hMASP-2的构建

目的 利用p Yr-adshuttle-4质粒构建重组腺病毒载体p Ad-4-h MASP-2。方法 应用PCR技术扩增甘露糖凝集素相关丝氨酸蛋白酶-2(human mannan-binding lectin associated serine protease-2,h MASP-2)基因,经Bam HⅠ和Eco RⅠ双酶切后与p Yr-adshuttle-4质粒连接,构建穿梭质粒p Yr-ads-4-h MASP-2,在LR酶作用下与腺病毒骨架载体p Ad/PL-DEST进行体外同源重组,获得重组腺病毒载体p Ad-4-h MASP-2,转染HEK293细胞,获得重组腺病毒r Adh MASP-2,应用酶切、PCR扩增及基因测序进行鉴定,并测定病毒滴度。将r Ad-h MASP-2感染小鼠,实时荧光定量PCR法检测h MASP-2基因m RNA在小鼠肺组织中的表达。结果 重组穿梭质粒p Yr-ads-4-h MASP-2经双酶切及测序证实构建正确,通过同源重组获得了重组腺病毒载体p Ad-4-h MASP-2,扩增出滴度为1.5×109 PFU/ml的重组腺病毒颗粒r Ad-h MASP-2,其能在小鼠肺组织中表达。结论 成功获得重组腺病毒载体p Ad-4-h MASP-2和重组腺病毒颗粒r Ad-h MASP-2,为体内外研究h MASP-2的活性提供了有效的转基因载体。     

应用AdMax系统构建携带HCV核心基因Core的重组腺病毒载体

目的应用AdMax系统构建携带丙型肝炎病毒(HCV)核心基因Core的重组腺病毒载体,为进一步研究防止HCV感染的基因疫苗和基因治疗奠定基础。方法RT-PCR法从丙型肝炎患者血清中扩增HCVCore基因,连接到腺病毒穿梭质粒的多克隆位点上,构建重组穿梭质粒pDC315-Core,在脂质体介导下与腺病毒辅助大质粒pBHGlox(delta)E1,3Cre共转染HEK293细胞,包装产生复制缺陷型重组腺病毒pAd-Core,经HEK293细胞扩增后,离子交换柱层析法纯化病毒,测定病毒颗粒数及滴度,并计算比活性及单细胞产量。结果重组腺病毒pAd-Core感染的HEK293细胞经PCR检测,可扩增出HCV核心基因Core片段,经测序证明,其插入序列与设计的HCV Core基因序列一致。扩增纯化后,重组腺病毒的比活性达0.034IU/VP,单细胞产量可达2.63×104VP/细胞。结论已成功构建重组腺病毒载体pAd-Core,为Core基因在腺病毒介导下的基因免疫和基因治疗的研究奠定了基础。     

细菌内同源重组构建人p21~(WAF1)基因重组腺病毒

目的构建人p21WAF1基因重组腺病毒载体,并在293细胞中包装制备重组腺病毒。方法将人p21WAF1基因亚克隆连接到腺病毒转移质粒pshuttle-cmv,得到阳性重组转移质粒psh-p21。先将腺病毒骨架质粒pAdEasy-1转化BJ5183菌,筛选得到AdBJ5183菌,再将PmeⅠ线性化的psh-p21转化AdBJ5183菌,经细菌内同源重组法构建重组腺病毒质粒pAdp21。经PacⅠ和BstXⅠ酶切及PCR鉴定,将正确的重组腺病毒质粒pAdp21转染293细胞包装病毒,用RT-PCR和PCR鉴定重组腺病毒及其稳定性。结果所构建的重组腺病毒质粒pAdp21,经PCR鉴定,可扩增出约500bp的片段,与预期大小相符。转染293细胞可包装成p21WAF1基因重组腺病毒,经电镜观察,具有典型的腺病毒特征。结论已成功地构建了重组腺病毒质粒pAdp21,并制备出重组腺病毒rAdp21。     

人S100A8重组腺病毒质粒的构建及鉴定

目的构建人S100A8(hS100A8)重组腺病毒质粒,为hS100A8的深入研究奠定基础。方法从pGST-hS100A8中扩增hS100A8片段,亚克隆至穿梭质粒pAdTrack-TOX,构建重组穿梭质粒pAdTrack-TOX-hS100A8。经酶切、PCR及测序鉴定,再经PmeⅠ酶切线性化后电转化感受态AdEasier细胞,获得重组腺病毒质粒pAdhS100A8,经PacⅠ酶切后转染至HEK293细胞进行包装,制备重组腺病毒,扩增后进行病毒滴度测定及RT-PCR和Western blot鉴定。结果重组穿梭质粒pAdTrack-TOX-hS100A8及腺病毒质粒pAdhS100A8经鉴定均构建正确;重组腺病毒AdhS100A8在HEK293中成功包装,扩增后病毒滴度为1011 IU/ml;hS100A8在HEK293细胞中成功表达。结论成功构建了hS100A8重组腺病毒质粒,为深入研究hS100A8奠定了基础。     

Kozak序列引导的人p53基因重组智能腺病毒载体的构建与表达

目的构建Kozak序列引导的人p53(khp53)基因重组智能腺病毒载体rAdMH-khp53,并检测p53基因的表达。方法将带有Kozak序列的p53基因克隆到重组腺病毒穿梭载体中,再利用AdMaxTMHi-IQ系统,获得重组腺病毒,检测病毒滴度,并进一步感染Saos-2细胞,利用RT-PCR及Western blot检测p53基因的表达。结果khp53基因成功克隆到腺病毒载体中,重组腺病毒滴度为1.63×108IU/ml,RT-PCR方法检测到p53基因的转录产物,Western blot检测到p53基因在Saos-2细胞中的高水平表达。结论已成功构建了带有Kozak序列的重组腺病毒载体rAdMH-khp53,并高效表达人p53基因。     

狂犬病毒糖蛋白基因-腺病毒E3区缺失转移表达载体的构建及表达

目的构建狂犬病毒糖蛋白基因-腺病毒E3缺失转移表达载体,并在MDCK细胞系统中高效表达。方法将含狂犬病毒SRV9株糖蛋白(Rgp)cDNA的pGT载体,经双酶切后回收Rgp基因片段,与经双酶切的真核表达载体pIRES1neo连接,得到pIRES1Rgp,再经双酶切后回收2623bp片段,与E3缺失载体pBE3L连接,得到含狂犬病毒糖蛋白基因-腺病毒E3缺失转移表达载体pBE3LCRgp,再转染MDCK细胞。结果pBE3LCRgp转染的MDCK细胞,经间接ELISA和间接免疫荧光法在其培养上清中均能检出Rgp的高效表达。结论已成功构建狂犬病毒糖蛋白基因-腺病毒E3缺失转移表达载体,并在MDCK细胞中高效表达。     

人巨细胞病毒糖蛋白gB基因重组腺病毒载体的构建及包装

目的构建携带有人巨细胞病毒(HCMV)糖蛋白gB基因的重组腺病毒载体,并在HEK293细胞中进行包装。方法将gB基因克隆至穿梭质粒Track-CMV,构建重组质粒Track-CMV/gB,亚克隆至转移载体pAD-Easy-1,构建重组质粒pAD-Easy-1/gB,将该重组骨架质粒转染HEK293细胞,利用HEK293细胞产生重组腺病毒。空斑法及PCR法挑选重组病毒,荧光显微镜观察标志蛋白(绿色荧光蛋白)的表达,利用噬斑法检测病毒滴度。结果重组腺病毒载体经酶切鉴定证明构建正确,转染重组腺病毒载体的HEK293细胞经PCR扩增,可见约700bp的目的基因片段,荧光显微镜观察可见绿色荧光蛋白表达,空斑试验检测病毒滴度为2×106PFU/ml。结论已成功构建了含有gB基因的重组腺病毒载体,为进一步研制重组腺病毒载体HCMV疫苗提供了条件。     

Concepts in Oncolytic Adenovirus Therapy

Oncolytic adenovirus therapy is gaining importance as a novel treatment option for the management of various cancers. Different concepts of modification within the adenovirus vector have been identified that define the mode of action against and the interaction with the tumour. Adenoviral vectors allow for genetic manipulations that restrict tumour specificity and also the expression of specific transgenes in order to support the anti-tumour effect. Additionally, replication of the virus and reinfection of neighbouring tumour cells amplify the therapeutic effect. Another important aspect in oncolytic adenovirus therapy is the virus induced cell death which is a process that activates the immune system against the tumour. This review describes which elements in adenovirus vectors have been identified for modification not only to utilize oncolytic adenovirus vectors into conditionally replicating adenoviruses (CRAds) that allow replication specifically in tumour cells but also to confer specific characteristics to these viruses. These advances in development resulted in clinical trials that are summarized based on the conceptual design.     

作为基因载体的低分子量壳聚糖的制备及研究进展

低分子量壳聚糖作为非病毒性基因治疗载体有着广阔的前景,已成为研究的热点。综述了低分子量壳聚糖的制备方法以及载基因的研究进展,并讨论了影响转染的因素。     

Adenovirus Vectors Expressing Eight Multiplex Guide RNAs of CRISPR/Cas9 Efficiently Disrupted Diverse Hepatitis B Virus Gene Derived from Heterogeneous Patient

Hepatitis B virus (HBV) chronically infects more than 240 million people worldwide, causing chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Genome editing using CRISPR/Cas9 could provide new therapies because it can directly disrupt HBV genomes. However, because HBV genome sequences are highly diverse, the identical target sequence of guide RNA (gRNA), 20 nucleotides in length, is not necessarily present intact in the target HBV DNA in heterogeneous patients. Consequently, possible genome-editing drugs would be effective only for limited numbers of patients. Here, we show that an adenovirus vector (AdV) bearing eight multiplex gRNA expression units could be constructed in one step and amplified to a level sufficient for in vivo study with lack of deletion. Using this AdV, HBV X gene integrated in HepG2 cell chromosome derived from a heterogeneous patient was cleaved at multiple sites and disrupted. Indeed, four targets out of eight could not be cleaved due to sequence mismatches, but the remaining four targets were cleaved, producing irreversible deletions. Accordingly, the diverse X gene was disrupted at more than 90% efficiency. AdV containing eight multiplex gRNA units not only offers multiple knockouts of genes, but could also solve the problems of heterogeneous targets and escape mutants in genome-editing therapy.     

ErbB3-Targeting Oncolytic Adenovirus Causes Potent Tumor Suppression by Induction of Apoptosis in Cancer Cells

Cancer is a multifactorial and deadly disease. Despite major advancements in cancer therapy in the last two decades, cancer incidence is on the rise and disease prognosis still remains poor. Furthermore, molecular mechanisms of cancer invasiveness, metastasis, and drug resistance remain largely elusive. Targeted cancer therapy involving the silencing of specific cancer-enriched proteins by small interfering RNA (siRNA) offers a powerful tool. However, its application in clinic is limited by the short half-life of siRNA and warrants the development of efficient and stable siRNA delivery systems. Oncolytic adenovirus-mediated therapy offers an attractive alternative to the chemical drugs that often suffer from innate and acquired drug resistance. In continuation to our reports on the development of oncolytic adenovirus-mediated delivery of shRNA, we report here the replication-incompetent (dAd/shErbB3) and replication-competent (oAd/shErbB3) oncolytic adenovirus systems that caused efficient and persistent targeting of ErbB3. We demonstrate that the E1A coded by oAd/shErbB, in contrast to dAd/shErbB, caused downregulation of ErbB2 and ErbB3, yielding stronger downregulation of the ErbB3-oncogenic signaling axis in in vitro models of lung and breast cancer. These results were validated by in vivo antitumor efficacy of dAd/shErbB3 and oAd/shErbB3.     

腺病毒载体介导的HSV-tk基因杀伤肿瘤细胞的研究

目的 探讨ＨＳＶ－ｔｋ基因对各种肿瘤细胞的杀伤作用及人、鼠瘤细胞对其敏感性及瘤细胞表面的αｖ 整合素对腺病毒载体转染的影响。方法用同源重组法构建 ＡｄＣＭＶ ｔｋ基因;蚀斑形成法对重组腺病毒进行扩增、 滴定;Ｘ－ｇａｌ染色法观察腺病毒转染率,结晶紫染色法检测 ＡｄＣＭＶｔｋ／ＧＣＶ的杀伤作用。结果 ＡｄＣＭＶｔｋ对肿瘤细胞 的杀伤强度在一定范围内与ＡｄＣＭＶｔｋ的剂量呈正相关;对人类的Ｈｅｌａ、ＧＲＣ、Ｈｅｐ－２瘤细胞达１００％转染所需的腺病 毒感染复数量（ｍｕｌｔｉｐｌｉｃｉｔｙ　ｏｆ　ｉｎｆｅｃｔｉｏｎ,ｍ．ｏ．ｉ）较鼠Ｌｅｗｉｓ、ＢＴＴ７３９瘤细胞的ＭＯＩ量低;在相同ＭＯＩ病毒量时,有αｖ整合 素的瘤细胞转染率高于无αｖ整合素的瘤细胞。结论ＡｄＣＭＶｔｋ／ＧＣＶ具有较明显的杀伤肿瘤细胞的作用,且有种属 差异,对人瘤细胞作用大于鼠瘤细胞,瘤细胞表面的αｖ整合素有利于腺病毒的转染。