hNIS/TK基因共转染介导131I/GCV对肝癌细胞株的毒性作用

背景与目的:与传统的单纯疱疹病毒胸苷激酶(herpes simplex virus thymidine kinase,HSV-TK)/丙氧鸟苷(ganciclovir,GCV)肿瘤自杀系统相比,人钠/碘同向转运体(human sodium-iodide symporter,hNIS)是近年来发现的新型治疗基因.然而,两者的疗效尚需进一步提高.本研究旨在探索hNIS介导的放射性核素体系与HSV-TK/GCV自杀基因体系对肝癌细胞的联合毒性作用.方法:构建EF1-a启动子调控下的hNIS的表达载体与CMV启动子调控下的GFP和HSV-TK共表达载体,慢病毒包装后转染肝癌细胞HepG2,荧光显微镜下观察重组肿瘤细胞HepG2/NTG荧光蛋白的表达;采用RT-PCR技术进一步检测目的基因hNIS和HSV-TK的表达情况;MTT检测GCV对HepG2/NTG的杀伤作用;摄碘试验及流出试验评价HepG2/NTG对碘的摄取及滞留情况;最后通过克隆形成实验评价GCV和131I对HepG2/NTG的单独及联合杀伤作用.结果:RT-PCR技术、荧光显像证实hNIS、GFP和HSV-TK基因在肝癌细胞中成功表达;与对照组相比,HepG2/NTG的摄碘高出76倍,20 min摄碘率最高,其后表现出碘外流,有效半衰期不到10 min,同时这种碘摄取能被NaClO4特异性抑制.GCV或131I对HepG2/NTG的毒性作用呈现剂量依赖性:50μg/mL GCV作用72 h后,实验组细胞的存活率仅为(33.98±2.71)%;放射性浓度为7.4MBq/mL的131I处理7 h后,细胞的存活率仅为(41.17±0.72)%;GCV和131I联合作用后,细胞的存活率仅为(8.55±1.22)%,较单一药物作用细胞存活率下降了6倍.结论:131I/GCV对重组肝癌细胞产生显著的毒性作用,提示慢病毒介导hNIS/TK基因共转染介导肿瘤的放射化学治疗是可行的.     

RV-HSV-TK/GCV自杀基因系统治疗子宫颈癌的体内实验研究

目的探讨HSV-TK/GCV自杀基因系统对小鼠子宫颈癌细胞系Hela形成肿瘤的体内杀伤作用及其产生的旁观者效应。方法体内实验分Hela对照组、Hela/TK Hela(1∶9)组、Hela/TK Hela(1∶1)组和Hela/TK组。分别按实验组别要求接种3.0×106细胞/只于BALB/C小鼠的右腋窝皮下,观察各组肿瘤形成及肿瘤治疗情况。治疗结束后将标本制成石蜡切片和超薄切片进行病理学分析,RT-PCR检测HSV-TK基因在肿瘤组织中的表达情况。统计学分析采用SPSS软件进行完全随机的方差分析(ANOVA)。结果丙氧鸟苷(ganciclovir,GCV)可明显抑制Hela/TK细胞在BALB/C小鼠体内的肿瘤形成。经GCV治疗后,Hela/TK Hela(1∶9)、Hela/TK Hela(1∶1)组和Hela/TK组分别较对照组肿瘤体积缩小约11.1%、30.6%和47.2%;RT-PCR检测HSV-TK基因在肿瘤组织中有表达。实验组肿瘤组织与对照组相比存在明显的病理学改变。结论HSV-TK/GCV自杀基因系统在体内对子宫颈癌细胞有杀伤作用,且存在明显的旁观者效应。     

腺病毒介导HSV-TK/GCV系统联合放射治疗口腔鳞癌的研究

目的 探讨单纯疱疹病毒胸苷激酶基因（HSV－TK）／丙氧鸟苷（GCV）自杀基因系统对放射治疗的增敏作用。方法 口腔鳞癌细胞（Tca8113细胞系）经HSV－TK／GCV系统治疗后给予放射治疗，采用LQ和单击多靶（SHMT）模型分析细胞存活曲线参数。结果 细胞存活曲线分析显示：单纯放射治疗组其α为0.1074,β为0.0158,D0为2.2576,Dq为3.5413；与单纯放射治疗组比较，HSV－TK／GCV治疗组α（0.2127)和α：β（9.496)值大，D0（1.4526)和Dq(2.2257)值小，其放射增敏率（SER）为1.55。结论 HSV－TK／GCV系统具有放射增敏作用，可提高放射治疗对口腔鳞癌的治疗疗效。     

HSV-tk/GCV系统治疗恶性肿瘤研究进展

自杀基因治疗恶性肿瘤是国内外研究的热点.因其独有的旁观者效应,可克服基因转导率低的缺陷,并可与其他方法联合应用,通过靶向调控机制增强疗效,是较为有效且具有临床应用前景的基因疗法.现综述近年来HSV-tk/GCV治疗恶性肿瘤研究进展.     

自杀基因在肝癌治疗中的应用现状

目前，在自杀基因治疗肝癌的研究中，通过联合基因治疗，受体介导定位、改变酶特性，寻找新的自杀基因系统，以及选择不同用药策略和途径等，方法将自杀基因高效导入靶细胞， 并使之表达，从而增强特异性杀伤肝脏肿瘤细胞作用。临床应用前景广阔。     

pGL3-hTERT-tk/GCV对胃癌细胞的促凋亡作用

目的:探讨重组质粒pGL3hTERTtk/GCV对胃癌细胞的促调亡作用。方法：以基因工程方法构建重组质粒pGL3hTERTtk和相应的荧光报告质粒pGL3hTERTtkLuc+;脂质体LipofectamineTM2000瞬时转染胃癌细胞系SGC7901并用GCV干预,荧光显微镜观察细胞形态变化和转染效率,TUNEL标记和流式细胞术观察转染后胃癌细胞的凋亡;以上实验均以正常肝细胞L02为对照。结果：经鉴定,重组质粒pGL3hTERTtk中tk片段的长度为1 100 bp。荧光素酶标记的阳性、阴性对照及治疗报告质粒pGL3hTERTtkLuc+均能有效转染高表达端粒酶活性的胃癌细胞SGC7901,转染效率为(8.2±114)%。重组质粒转染胃癌细胞后与GCV共育4 d,细胞的凋亡率为(60.0±1.56)%;被pGL3hTERTtk转染的肿瘤细胞细胞周期发生了变化,处于细胞周期早期的细胞大量凋亡,早期凋亡率为（47.1±1.35）%。〖HT5W〗结论：〖HT5"SS〗pGL3hTERTtk/GCV对胃癌细胞有强烈的杀伤作用,但不影响正常细胞的生长,有潜在临床应用前景。     

HSVTK/GCV自杀基因系统治疗乳腺癌的研究

 目的　探讨HSV TK/GCV自杀基因系统对小鼠乳腺癌细胞系MA782 / 5S 810 2体外及体内杀伤作用及其产生的旁观者效应。方法　采用脂质体转染法将GINaTK载体转入包装细胞PA317。取病毒上清液感染小鼠乳腺癌细胞MA782 / 5S 810 2 ,得到带有HSV TK基因的MA782 / 5S 810 2 /TK细胞 ,并将其分别用于体外和体内实验。结果　载体HSV TK导入了PA317细胞。体外实验结果显示 ,当MA782 / 5S 810 2 /TK细胞数占混合细胞 10 %时 ,低浓度 (10 μg/ml)的GCV就可将 5 0 %左右的肿瘤细胞杀死。体内实验结果显示GCV可明显抑制MA782 / 5S 810 2 /TK细胞在BALB/C小鼠体内的肿瘤形成。实验组肿瘤组织与对照组相比存在明显的病理学改变。结论　逆转录病毒可介导HSV TK基因转入小鼠乳腺癌细胞MA782 / 5S 810 2并获稳定表达 ,HSV TK/GCV自杀基因系统在体内外对乳腺癌细胞均有杀伤作用 ,且存在明显的旁观者效应。     

新型基因载体G5-PAMAM-D在前列腺癌HSV-tk/GCV自杀基因系统中的应用

背景与目的:考察纳米级阳离子聚酰胺-胺型树枝状聚合物(polyam idoam ine dendrimers,PAMAM-D)作为基因载体进行前列腺癌自杀基因治疗的可行性,为前列腺癌的基因治疗寻找新的基因载体。方法:以第5代PAMAM-D(G5-PAMAM-D)为载体将含增强型荧光蛋白(EGFP)基因片段的重组质粒pEGFP-C1转染至前列腺癌细胞系PC-3和22Rv1,成功表达EGFP后,再以G5-PAMAM-D为载体将含HSV-tk自杀基因的真核表达重组质粒pcDNA3-tk转染至前列腺癌细胞系PC-3和22Rv1,转染48h后,对转染的两种细胞给予浓度为0、10、100、1000、10000μmol/L前体药更昔洛韦(Ganciclovir,GCV),24h后采用MTT比色法测定药物对细胞增殖的影响。制作前列腺癌皮下荷瘤小鼠,将G5-PAMAM-D/pcDNA3-tk复合物瘤内注射,24h后腹腔注射GCV,观察这一复合物体内对肿瘤生长的抑制作用。结果:荧光观察及FCM结果证明G5-PAMAM-D可将pEGFP-C1转入两种前列腺癌细胞并表达EGFP。采用G5-PAMAM-D将pcDNA3-tk重组质粒转染PC-3和22Rv1细胞,给不同浓度的前体药GCV后,实验组细胞与对照组相比有明显浓度依赖性生长抑制。荷瘤小鼠在给予瘤内注射G5-PAMAM-D/pcDNA3-tk复合物后,行腹腔注射GCV,治疗后第40天,实验组肿瘤体积(1135±245mm3)与对照组裸质粒组(9965±2109mm3)和PAMAM-D组(8357±1956mm3)相比肿瘤生长明显被抑制(P<0.01),生存时间延长。结论:G5-PAMAM-D可作为前列腺腺癌自杀基因治疗的基因载体,有良好的应用前景。     

叶酸修饰的G5-PAMAM-D介导HSV-TK/GCV自杀基因系统治疗前列腺癌的体外实验研究*

目的:探讨叶酸修饰的第五代聚酰胺- 胺型树枝状聚合物（G5-PAMAM-D-fol ）作为基因载体进行前列腺癌自杀基因治疗的可行性。方法:以G5-PAMAM-D-fol 为基因载体将含有自杀基因HSV-TK 的重组质粒pcDNA 3-tk转染至前列腺癌细胞系PC- 3 和LNCaP ,24h 后以RT-PCR 法检测HSV-TK 基因在两种前列腺癌细胞系中的mRNA 表达;再次转染后24h,对转染的两种细胞分别给予不同浓度的前体药物更昔洛韦（GCV ）,48h 后采用四甲基偶氮唑盐比色法（MTT 法）检测细胞抑制率。结果:RT-PCR结果证明G5-PAMAM-D-fol 可将重组质粒pcDNA 3-tk转染2 种前列腺癌细胞并转录HSV-TK 基因。MTT 实验反映出A 组（G5-PAMAM-D-fol/pcDNA 3-tk）对PC- 3 和LNCaP 细胞有明显的杀伤作用,并且比B 组（G5-PAMAM-D/pcDNA3-tk）的细胞抑制率更高。C 组（G5-PAMAM-D-fol ）和D 组（G5-PAMAM-D）随着GCV 浓度的增加细胞生长并未受到明显的抑制,而且前者并未表现出比后者更明显的细胞杀伤作用。结论:G5-PAMAM-D-fol 能够在体外将自杀基因重组质粒成功转入前列腺癌细胞并表达HSV-TK 基因,其靶向性强且细胞毒性低。      

Evaluation of miR-122-regulated suicide gene therapy for hepatocellular carcinoma in an orthotopic mouse model

Objective： Intratumoral administration of adenoviral vector encoding herpes simplex virus （HSV） thymidine kinase （TK） gene （Ad-TK） followed by systemic ganciclovir （GCV） is an effective approach in treating experimental hepatocellular carcinoma （HCC）. However, hepatotoxicity due to unwanted vector spread and suicide gene expression limited the application of this therapy, miR-122 is an abundant, liver-specific microRNA whose expression is decreased in human primary HCC and HCC-derived cell lines. These different expression profiles provide an opportunity to induce tumor-specific gene expression by miR-122 regulation. Methods： By inserting miR-122 target sequences （miR-122T） in the 3＇ untranslated region （UTR） ofTK gene, we constructed adenovirus （Ad） vectors expressing miR-122-regulated TK （Ad-TK-122T） and report genes. After intratumoral administration of Ad vectors into an orthotopic miR-122-deficient HCC mouse model, we observed the miR-122-regulated transgene expression and assessed the antitumor activity and safety of Ad-TK-122T. Results： Insertion of miR-122T specifically down-regulated transgene expression in vitro and selectively protected the miR-122-positive cells from killing by TK/GCV treatment. Insertion of miR-122T led to significant reduction of tansgene expression in the liver without inhibition of its expression in tumors in vivo, resulting in an 11-fold improvement of tumor-specific transgene expression. Intratumoral injection of Ad vectors mediated TK/GCV system led to a vector dosage-dependent regression of tumor. The insertion of miR-122T does not influence the antitumor effects of suicide gene therapy. Whereas mice administrated with Ad-TK showed severe lethal hepatotoxicity at the effective therapeutic dose, no liver damage was found in Ad-TK-122T group. Conclusions： miR-122-regulated TK expression achieved effective anti-tumor effects and increased the safety of intratumoral delivery of adenovirus-mediated TK/GCV gene therapy for miR-122-deficient HCC.     

microRNA-122抑制胰腺癌细胞增殖、迁移和侵袭

目的 明确microRNA-122(miR-122)在胰腺癌中的表达及miR-122对胰腺癌细胞增殖、迁移和侵袭的作用.方法 采用RT-qPCR方法检测20例胰腺癌组织、胰腺癌细胞株(ASPC1、PANC1、MP和SW1990)和人源正常胰腺导管上皮细胞株(HPDE)中miR-122的表达量.将miR-122模拟类似物...     

HSV—tk／GCV系统对神经胶质瘤的自杀基因治疗研究

目的在ｉｎｖｉｔｒｏ和ｉｎｖｉｖｏ水平建立致死神经胶质瘤的ＨＳＶ－ｔｋ／ＧＣＶ自杀基因系统,并验证该系统的有效性。方法用携带单纯疱疹病毒胸苷激酶（ＨＳＶ－ｔｋ）基因的重组逆转录病毒,感染大鼠神经胶质瘤细胞Ｃ６,筛选稳定表达ｔｋ的克隆细胞Ｃ６／ｔｋ;经生长抑制试验,比较Ｃ６／ｔｋ细胞对三种核苷类似物ＧＣＶ、ＢＶｄＵ和ＡＣＶ的敏感性;Ｃ６／ｔｋ细胞在裸鼠皮下成瘤,用ＧＣＶ进行治疗并观察疗效。结果ｔｋ基因整合入Ｃ６细胞并在Ｃ６／ｔｋ细胞中稳定表达;生长抑制试验表明,ＧＣＶ是最为有效的原药,Ｃ６／ｔｋ细胞对ＧＣＶ高度敏感,ＩＣ５０＜０．２μｍｏｌ／Ｌ,而野生型Ｃ６细胞和转染空载病毒载体的Ｃ６／０细胞对ＧＣＶ的ＩＣ５０≥１００μｍｏｌ／Ｌ,相差５００多倍。裸鼠ｉｎｖｉｖｏ实验得到相应结果,治疗组肿瘤受到明显抑制和杀伤。结论在ｉｎｖｉｔｒｏ和ｉｎｖｉｖｏ水平,表达ｔｋ基因的肿瘤细胞均被ＧＣＶ有效杀伤,这表明ＨＳＶ－ｔｋ／ＧＣＶ自杀基因系统有可能成为基因治疗脑瘤的有效方法。     

肿瘤HSV-tk/GCV自杀基因治疗系统的增效策略

HSV-tk/GCV系统是目前应用最广泛的自杀基因治疗系统之一,其重要性日益上升.然而,许多缺陷严重限制了其应用广度和治疗效率.为满足更多领域的研究需要并实现临床治疗,科研人员投入了大量精力改善HSV-tk/GCV系统,增强其治疗效率.增效策略主要包括加强亲和性、提高表达水平、双自杀基因系统联合、诱发免疫系统协同作用、激活细胞周期、与其他肿瘤治疗方法相结合等.本文在阐明HSV-tk/GCV系统的自杀机理的基础上,分析了多种增效策略及效果,列举了应用领域并对未来发展作探讨.     

A novel Bifidobacterium infantis-mediated TK/GCV suicide gene therapy system exhibits antitumor activity in a rat model of bladder cancer

Bladder cancer is the ninth most common malignancy in the world. Successful clinical management remains a challenge. In order To search for novel targeted and efficacious treatment, we sought to investigate anti-tumor activity of BI-TK suicide gene therapy system in a rat model of bladder tumors. We first constructed and tested an anaerobic Bifidobacterium infantis-mediated thymidine kinase (BI-TK) suicide gene therapy system. To test the in vivo efficacy of this system, we established a rat model of bladder tumors, which was induced by N-methyl-nitrosourea perfusion. Bifidobacterium infantis containing the HSV-TK (i.e., BI-TK) were constructed by transformation of recombinant plasmid pGEX - TK. The engineered BI-TK was injected into tumor-bearing rats via tail vein, followed by intraperitoneal injection of ganciclovir (GCV). Using the rat model of bladder tumors, we found that bladder tumor burdens were significantly lower in the rats treated with BI-TK/GCV group than that treated with normal saline control group (p <0.05). While various degrees of apoptosis of the tumor cells were detected in all groups using in situ TUNEL assay, apoptosis was mostly notable in the BI-TK/GCV treatment group. Immunohistochemical staining further demonstrated that the BI-TK/GCV treatment group had the highest level of caspase3 protein expression than that of the empty plasmid group and normal saline group (p < 0.05). Thus, our results demonstrate that the Bifidobacterium infantis-mediated TK/GCV suicide gene therapy system can effectively inhibit rat bladder tumor growth, possibly through increasing caspase 3 expression and inducing apoptosis.     

肿瘤HSV—tk／GCV自杀基因治疗系统的增效策略

HSV—tk／GCV系统是目前应用最广泛的自杀基因治疗系统之一,其重要性日益上升。然而,许多缺陷严重限制了其应用广度和治疗效率。为满足更多领域的研究需要并实现临床治疗,科研人员投入了大量精力改善HSV—tk／GCV系统,增强其治疗效率。增效策略主要包括加强亲和性、提高表达水平、双自杀基因系统联合、诱发免疫系统协同作用、激活细胞周期、与其他肿瘤治疗方法相结合等。本文在阐明HSV—tk／GCV系统的自杀机理的基础上,分析了多种增效策略及效果,列举了应用领域并对未来发展作探讨。     

HSV-TK/GCV体系对前列腺癌PC-3m细胞杀伤作用的实验研究

目的：探讨HSV－TK／GCV体系对前列腺癌PC-3m细胞的杀伤作用。方法：应用逆转录病毒载体将HSV－TK基因转染PC－3m细胞，经RT－PCR鉴定后，MTT、流式细胞仪、电镜等方法检测丙氧鸟苷（GCV）对转染后PC－3m细胞的杀伤作用，同时以未转染PC－3m细胞为对照。结果：GCV对正常PC－3m细胞毒性较低，而对转染后PC－3m细胞有较强的细胞毒作用，但旁观者效应不明显。结论：HSV－TK／GCV体系对前列腺癌细胞具有明显杀伤作用，有必要进一步研究。     

MicroRNA-122 Promotes Proliferation,Invasion and Migration of Renal Cell Carcinoma Cells Through the PI3K/Akt Signaling Pathway

Objective: MicroRNAs (miRNAs) are a small class of non-coding, single-stranded RNAs with a criticalrole in genesis and maintenance of renal cancer mainly through binding to 3’-untranslated regions (3’UTR) oftarget mRNAs, which causes a block of translation and/or mRNA degradation. The aim of the present studywas to investigate the potential effects of miR-122 in human renal cell carcinomas. Methods: The expressionlevel of miR-122 was quantified by qRT-PCR. MTT, colony formation, invasion and migration assays were usedto explore the potential functions of miR-122 in human renal cell carcinoma cells. Results: Cellular growth,invasion and migration in two A498 and 786-O cells were significantly increased after miR-122 transfection.Further experiments demonstrated that overexpression of miR-122 resulted in the increase of phospho-Akt(Ser473) and phospho-mTOR (Ser2448), then activation of mTOR targets, p70S6K and 4E-BP1. Conclusions:The up-regulation of miR-122 may play an important role in the progress of renal cancer through activatingPI3K/Akt signal pathway and could be a potential molecular target for anti-cancer therapeutics.     

ARE/SUZ12 dual specifically-regulated adenoviral TK/GCV system for CML blast crisis cells

Background

Treatment of blast phase chronic myeloid leukemia (BP-CML) remains a challenge, and the median survival is less than 6 months. Because effective treatments are lacking, we studied tight targeting of blast crisis CML cells using adenoviral (Ad) vectors expressing a HSV-TK system under dual control of a specific SUZ12 promoter and an antioxidant response element (ARE).

Methods

A potential SUZ12 promoter fragment was designed with bioinformatics databases and identified with a luciferase assay. Next, we cloned the ARE element of the NQO1 gene and developed Ad vectors expressing TK kinase or luciferase under the dual control of a specific SUZ12 promoter and an ARE element. An in vitro transfection assay with Ad-ARE/SUZ12-Luc was used to determine promoter activity of ARE/SUZ12 regulatory element in blast crisis CML cells. After incubating human BP-CML-derived cells with Ad-ARE/SUZ12-TK and ganciclovir, Western blot, CCK8, Immunofluorescent assays and Annexin V assays were conducted to assess the efficacy of an ARE/SUZ12 dual-specific TK/GCV system for BP-CML cell lines.

Results

Here, luciferase data confirmed significantly higher and specificer promoter activity of the ARE/SUZ12 composite component in CML blast crisis-derived cell lines (K562, KCL22, and K562/G01) compared to HepG2 cells, and Ad-AS-TK/GCV system could exhibit enhanced apoptotic effects and decreased cell viability for BP-CML cell lines. Additionally, Ad-AS-TK/GCV system altered expression of cycle-related and apoptosis-related proteins in BP-CML cell lines.

Conclusions

Thus, ARE/SUZ12 dual targeting TK/GCV system was effective in killing BP-CML cells. Moreover, efficacy and specificity of CML cell eradication were enhanced by synergistic effects of ARE/SUZ12 dual-specific regulation. We conclude that suicide gene-targeted therapy might hold promise for BP-CML treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0139-4) contains supplementary material, which is available to authorized users.     

MicroRNA-27b inhibits the development of melanoma by targeting MYC

Cutaneous malignant melanoma is a malignancy with one of the fastest increasing incidence rates worldwide; however, the mechanism underlying the occurrence and development of melanoma remains unclear. The aim of the present study was to identify novel biomarkers for the occurrence and development of melanoma. The results of the present study demonstrated that the expression levels of microRNA (miR)-27b were decreased in melanoma tissue samples compared with those in adjacent noncancerous tissue samples and cells according to online and experimental data. By contrast, MYC expression levels were upregulated in melanoma compared with those in adjacent noncancerous tissue samples. miR-27b overexpression significantly inhibited A375 and A2085 melanoma cell DNA synthesis, viability and invasive ability. Dual-luciferase reporter assay results demonstrated that miR-27b inhibited MYC expression through binding to the 3′-untranslated region of MYC mRNA. MYC knockdown in melanoma cells exerted similar effects to those of miR-27b overexpression on DNA synthesis, cell viability and invasive ability; the effects of miR-27b inhibition were significantly reversed by MYC knockdown. In conclusion, the miR-27b/MYC axis may modulate malignant melanoma cell biological behaviors and may be a potential target for melanoma treatment.