腺病毒介导的肝癌靶向SEA-CD80基因治疗及免疫学机制的初步研究

目的: 观察肝癌靶向性葡萄球菌肠毒素A (SEA)/CD80基因重组腺病毒载体对肝癌的疗效,并对其免疫学机制进行初步研究.方法: 利用AdEasy腺病毒系统分别构建并制备甲胎蛋白(AFP)启动子和增强子Ⅰ调控的SEA和/或CD80基因重组腺病毒载体, 然后采用瘤体内直接注射的方式对小鼠皮下移植性肝癌进行治疗, 采用RT-PCR和Western blot方法检测腺病毒注射部位的SEA和CD80 mRNA和蛋白的表达情况; 采用ELISpot方法和LDH释放实验分别检测脾脏淋巴细胞中肝癌特异性IFN-γ分泌细胞的频数和细胞毒性T细胞(CTLs)对Hepa1-6细胞的特异杀伤活性; 通过观察荷瘤小鼠经治疗后肿瘤体积的变化及生存时间, 评价重组腺病毒对肝癌的治疗作用.结果: 我们构建的腺病毒能够使SEA和/或CD80 mRNA和蛋白靶向地在肝癌组织中表达; 与空载体组和PBS对照组相比, 双基因组和单基因组分泌IFN-γ的T细胞数量均明显增多, CTL对Hepa1-6细胞的特异性杀伤作用均明显增强, 荷瘤小鼠肿瘤体积明显减小, 生存期明显延长; 双基因组的疗效和对免疫系统的激活作用明显高于单基因组; CD80 和SEA的组之间、空载体和PBS组之间无明显差异.结论: 我们制备的肝癌靶向性重组腺病毒对肝癌有良好的治疗作用, 联合基因治疗优于单个基因治疗.     

SEA-CD80基因过表达Hepa1-6肝癌细胞体外诱导的免疫学效应

目的观察经SEA和CD80重组腺病毒感染Hepa1-6肝癌细胞后体外能否诱导抗肿瘤免疫学反应。方法 Hepa1-6细胞分别经空载体腺病毒Ad(空)和重组腺病毒Ad-MMRE-mTERT-B7、Ad-MMRE-mTERT-SEA、Ad-MMRE-mTERT-BIS感染后,和小鼠脾淋巴细胞共培养,然后采用Brdu酶联免疫法(ELISA)检测淋巴细胞增殖;流式细胞术检测T淋巴细胞亚群增殖;ELISA法检测细胞因子IL-2、TNF-α和IFN-γ的产生;LDH释放法检测CTLs对Hepa1-6的杀伤作用。结果与感染空载体腺病毒Ad(空)和未感染Hepa1-6细胞相比,经重组腺病毒感染的Hepa1-6细胞体外能够显著诱导脾淋巴细胞的增殖,其中CD3+CD4+和CD3+CD8+T淋巴细胞增殖显著;细胞因子TNF-α、IFN-γ和IL-2的产生显著升高;CTLs对肿瘤细胞的杀伤活性显著增强;双基因过表达Hepa1-6细胞体外诱导的免疫应答高于单基因过表达Hepa-6细胞。结论 Hepa-6细胞经重组腺病毒感染后,表达在细胞膜上的SEA和CD80均具有免疫学活性,为今后采用所构建重组腺病毒进行肿瘤的免疫基因治疗提供了实验依据。     

小鼠TERT启动子调控的CD80-SEA基因重组腺病毒载体的构建及在肝癌细胞中的表达鉴定

目的:构建小鼠端粒酶反转录酶(mTERT)启动子调控的葡萄球菌肠毒素A(SEA)和CD80基因共表达重组腺病毒载体,并观察其介导的SEA和CD80在小鼠肝癌细胞Hepa1-6中的表达情况。方法:采用AdEasy腺病毒体系,亚克隆mTERT核心启动子区至穿梭质粒pShuttle2,并在其上游插入myc-Max反应元件MMRE,用来调控SEA及CD80基因的表达,构建SEA和CD80基因共表达重组腺病毒载体Ad-MMRE-mTERT-BIS,制备病毒并纯化,然后将病毒以感染复数为100的浓度分别感染肝癌细胞系Hepa1-6和成纤维细胞系NIH3T3。采用免疫荧光染色法检测SEA和CD80在细胞膜表面的表达情况。结果:重组腺病毒载体Ad-MMRE-mTERT-BIS感染的Hepa1-6肝癌细胞膜上能够共表达SEA和CD80;而病毒感染的NIH3T3细胞不能表达SEA和CD80。结论:成功地构建了mTERT启动子调控的SEA和CD80基因共表达重组腺病毒载体,能够调控SEA和CD80基因在肝癌细胞中的靶向表达,为进一步研究肝癌的靶向基因治疗奠定了基础。     

肝癌靶向性SEA-CD80基因共表达重组腺病毒载体的构建及表达鉴定

目的:构建肝癌靶向性葡萄球菌肠毒素A(SEA)和CD80基因共表达重组腺病毒载体。方法:首先利用现有的腺病毒穿梭质粒pShuttle和pShuttleCMV,构建新的不带CMV增强子/启动子而带有polyA加尾信号穿梭质粒,命名为pShuttle2。将AFP增强子、启动子、SEA及CD80基因分别从已构建的pKSEP载体和pMD18TBIS载体上,分别亚克隆至pShuttle2中,再与腺病毒骨架质粒pAdEasy1共转化E.coliBJ5183。以获得的重组子转染HEK293细胞后制备重组腺病毒,然后感染高表达AFP的肝癌细胞系Hepa16和不表达AFP的黑色素瘤细胞系B16、成纤维细胞系NIH3T3。采用间接免疫荧光法,激光共聚焦显微镜观察和流式细胞术检测SEA和CD80在细胞膜表面的表达。采用3H掺入法检测膜表达的SEA诱导淋巴细胞增殖的活性。结果:以制备的重组腺病毒感染肿瘤细胞后,SEA和CD80能够靶向性地共表达在高表达AFP的Hepa16细胞膜上,而在不表达AFP的B16、NIH3T3细胞膜上不表达。结论:成功地构建肝癌靶向性SEA和CD80基因共表达重组腺病毒载体,为进一步研究SEA和CD80在肝癌靶向基因治疗中的联合应用及其抗肿瘤免疫机制奠定了基础。     

重组腺病毒载体mIL-12治疗小鼠黑色素瘤的实验研究

目的： 观察重组腺病毒载体AdmIL-12对小鼠黑色素瘤的治疗效应.方法： 皮下注射B16黑色素瘤细胞给C57BL/6小鼠建立荷瘤模型.于瘤内注射重组腺病毒载体AdmIL-12治疗, 观察皮下肿瘤的生长及荷瘤小鼠的存活期.采用乳酸脱氢酶（LDH）释放法检测荷瘤小鼠脾细胞的杀伤活性.结果： 重组腺病毒载体AdmIL-12治疗后, 能显著抑制荷瘤小鼠肿瘤的生长, 明显延长荷瘤小鼠的存活时间, 增强荷瘤小鼠脾细胞的杀伤活性.结论： 重组腺病毒载体AdmIL-12对小鼠黑色素瘤有显著的治疗效应.     

转移程度不同的小鼠肝癌细胞株对腹腔巨噬细胞免疫功能的影响

目的 研究转移程度不同的小鼠肝癌细胞株对腹腔巨噬细胞功能的影响.方法 在两株转移程度不同的小鼠腹水型肝癌模型中,取荷瘤小鼠腹腔巨噬细胞,检测其在干扰素γ(IFN-γ)和脂多糖(LPS)刺激下产生一氧化碳(NO)和肿瘤坏死因子α(TNF-α)的水平,并检测其活化后的杀伤能力.进一步采用夹心酶联免疫吸附测定(ELISA)方法,研究不同荷瘤小鼠腹水中IFN-γ与转化生长因子β1(TGF-β1)的水平,并用相应抗体封闭TGF-β1后,检测活化巨噬细胞产生NO能力及杀伤活性.结果 经IFN-γ和LPS活化后,荷瘤小鼠腹腔巨噬细胞分泌NO和TNF-α能力明显低于正常巨噬细胞,杀伤能力下降.高转移性肝癌小鼠巨噬细胞分泌NO水平和杀伤能力均低于低转移性小鼠,但其分泌TNF-α量较高.此外,荷瘤小鼠腹水含较高水平IFN-γ与TGF-β1,不同转移程度荷瘤小鼠IFN-γ水平接近,但高转移性肝癌小鼠腹水含更多TGF-β1,而且TGF-β1的封闭可导致与肿瘤细胞共培养的巨噬细胞分泌NO的能力部分恢复.结论 肿瘤细胞可以通过分泌TGF-β1等抑制性因子下调巨噬细胞的活性和免疫功能.肿瘤的转移程度可能与其分泌免疫抑制因子的能力相关.     

小鼠肝癌微波消融对宿主免疫细胞和细胞因子的影响

目的探讨小鼠肝癌微波消融(microwave ablation,MA)对宿主免疫细胞组成和细胞因子分泌的影响。方法建立C57BL/6J小鼠Hepa1-6细胞移植肝癌模型,对肿瘤进行微波消融或手术切除,分别用流式细胞仪和ELISA法检测治疗前后宿主周围血中的CD4 、CD8 、NK1.1 细胞组成(%)及血浆细胞因子IL-2、IL-10、IL-12、IFN-γ水平(ng/L)。结果荷瘤2～3周组鼠与正常组鼠比较,免疫细胞和细胞因子区别不显著。MA组较荷瘤组CD8 、CD4 T细胞及IL-2、IL-10无明显差别,NK1.1 细胞明显升高(P<0.05,n=6),IL-12、IFN-γ显著上升(均P<0.01,n=6)。手术组比荷瘤组免疫细胞和细胞因子也无明显变化。MA组比手术组CD8 、CD4 T细胞及IL-2、IFN-γ、IL-10无明显区别,NK1.1 细胞、IL-12明显上升(分别P<0.01、P<0.05,n=6)。结论MA原位灭活小鼠肝癌可促进Th2/Th1偏移及NK细胞组成的显著升高。     

IL-21基因治疗小鼠H22细胞皮下移植肝癌模型的效果评价

用已构建的mIL-21/pcDNA3.1重组质粒对H22细胞建立的小鼠肝癌模型进行基因治疗,观察IL-21对小鼠体内抗肿瘤免疫应答的影响及对小鼠生存的影响。采用BALB/c小鼠左腋皮下注射腹水型肝癌细胞株H22细胞建立小鼠移植肝癌模型,给荷瘤小鼠瘤体内注射mIL-21/pcDNA3.1进行基因治疗,MTT比色法检测IL-21对荷瘤小鼠T细胞增殖水平及NK细胞杀伤活性的影响,观察治疗后荷瘤小鼠生存情况及肿瘤生长情况的改变。病理检测结果显示,成功建立了小鼠移植型肝癌模型,MTT比色法显示基因治疗后小鼠T细胞增殖水平及NK细胞杀伤活性显著升高,荷瘤小鼠肿瘤生长速度减慢,生存期显著延长。IL-21基因治疗肝癌荷瘤小鼠可显著提高荷瘤小鼠体内抗肿瘤免疫应答水平,抑制肿瘤生长,延长荷瘤小鼠生存期。     

转染IL-21的CD34~+脐血造血干细胞抗裸鼠卵巢癌作用研究

目的 探讨IL-21转染的脐血造血干细胞(CD34~+UBSC·IL-21)对荷卵巢癌裸鼠的治疗作用.方法 从脐血分离CD34~+造血干细胞,体外培养扩增后用于重组体pIRES2-IL-21-EGFP转染.以肿瘤大小、荷瘤鼠生存期判断CD34~+UBSC-IL-21对荷瘤裸鼠的治疗效应.以RT-PCR、免疫荧光、ELISA、Western blot、脾细胞增殖试验及免疫组化法分别鉴定CD34~+UBSC和肿瘤组织中IL-21的表达及活性.裸鼠脾细胞中NK细胞含量及脾细胞的杀伤效应、血清中IFN-γ和TNF-α水平分别用FCM与ELISA检测.结果 pIRES2-IL-21-EGFP成功转染CD34~+UBSC.CD34~+UBSC-IL-21能抑制肿瘤生长,延长荷瘤裸鼠生存期,治疗鼠肿瘤局部能表达IL-21、血清IFN-γ和TNF-α水平升高,NK细胞含量及NK细胞杀伤活性明显增强,与其他组相比,差异有统计学意义(P<0.01).结论 转染IL-21的CD34~+UBSC有良好的抗裸鼠卵巢癌作用,该结果为临床使用UBSC为载体的基因治疗卵巢癌研究奠定了基础.     

表达CRT-E2融合蛋白肿瘤疫苗诱导特异性抗肿瘤免疫应答

目的:探讨表达钙网蛋白(Calreticulin,CRT)和HPV E2融合蛋白的肿瘤疫苗在小鼠体内诱导的抗肿瘤免疫应答.方法:转染重组质粒得到高表达CRT、E2和CRT-E2融合蛋白的肿瘤细胞,作为肿瘤疫苗隔周两次腹腔注射免疫小鼠,17天后观察成瘤率,检测NK细胞杀伤活性、特异性T细胞增殖能力、CIL活性以及睥淋巴细胞分泌IFN-γ水平,并观察荷瘤小鼠生存期.结果:高表达CRT-E2融合蛋白肿瘤疫苗免疫小鼠后,其成瘤率明显低于其他实验组,NK细胞杀伤活性、特异性T细胞增殖能力、CTL活性和脾淋巴细胞分泌IFN-γ水平均显著高于其它实验组(P＜0.01),生存期也明显延长(P＜0.01).结论:小鼠体内实验显示,表达CRT-E2融合蛋白肿瘤疫苗能够诱导特异性CD8+T细胞免疫应答和NK细胞活性,显著抑制了肿瘤生长.     

Haptic selective attention by foot and by hand

Nonvisual perceptions of a wielded object's spatial properties are based on the quantities expressing the object's mass distribution, quantities that are invariant during the wielding. The mechanoreceptors underlying the kind of haptic perception involved in wielding – referred to as effortful, kinesthetic, or dynamic touch – are those embedded in the muscles, tendons, and ligaments. The present experiment's focus was the selectivity of this muscle-based form of haptic perception. For an occluded rod grasped by the hand at some intermediate position along its length, participants can attend to and report selectively the rod's full length, its partial lengths (fore or aft of the hand), and the position of the grip. The present experiment evaluated whether participants could similarly attend selectively when wielding by foot. For a given rod attached to and wielded by foot or attached to (i.e. grasped) and wielded by hand, participants reported (by magnitude production) the rod's whole length or fractional length leftward of the point of attachment. On measures of mean perceived length, accuracy, and reliability, the degree of differentiation of partial from full extent achieved by means of the foot matched that achieved by means of the hand. Despite their neural, anatomical, and experiential differences, the lower and upper limbs seem to abide by the same principles of selective muscle-based perception and seem to express this perceptual function with equal facility.     

Luminol-independent chemiluminescence by phagocytes is markedly enhanced by dexamethasone,not by other glucocorticosteroids

The effect of several glucocorticosteroids on the generation of reactive oxygen species (ROS) was examined. The ROS assessed were O ₂ ^– , H₂O₂, OH·, and chemiluminescence (CL) (determined in the presence or absence of luminol), generated by both opsonized zymosan-stimulated neutrophils or monocytes and by the xanthine-xanthine oxidase system. Except for luminol-independent CL, only high concentrations (10^–4 M) of steroids could decrease each ROS. In contrast, luminol-independent CL generation in the phagocyte system was increased in a dose-dependent manner by the addition of dexamethasone, but not by any other steroid. Further, in lymphocyte cultures stimulated with Con A for four days, luminol-independent CL generation was demonstrated and enhanced by the addition of dexamethasone, although CL generation was not detected in the absence of dexamethasone. These findings provide evidence that CL does not always represent light specific to ROS, and they suggest the possibility that dexamethasone induces emission of light at sites of inflammation.     

Intrastromal invasion by limbal epithelial cells is mediated by epithelial-mesenchymal transition activated by air exposure

Corneal epithelial stem cells are located in the basal layer of the limbus between the cornea and the conjunctiva. Regulation of these limbal epithelial progenitor cells by the stromal niche dictates corneal surface health. To further characterize this process, limbal explants were cultured at the air-fluid interface, termed air-lifting, to stimulate the niche. As compared to submerged cultures, air-lifting significantly promoted epithelial stratification, migration, proliferation, and intrastromal invasion by limbal epithelial cells. Epithelial intrastromal invasion was noted when the limbal, but not corneal, epithelium was recombined with the limbal stroma containing live, but not dead, cells. Invading limbal basal cells displayed up-regulated nuclear expression of p63 and Ki67, down-regulated E-cadherin and cornea-specific keratin 3, and switched expression of beta-catenin from intercellular junctions to the nucleus and cytoplasm, indicating the activation of the Wnt/beta-catenin pathway. Invaded cells isolated by collagenase from the stroma of air-lifted, but not submerged, explants showed vivid clonal growth on 3T3 fibroblast feeder layers and complete epithelial-mesenchymal transition by expressing nuclear p63 and cytoplasmic S100A4. These findings collectively suggest that epithelial-mesenchymal transition via the Wnt/beta-catenin pathway influences the fate of limbal epithelial cells, likely to be progenitor cells, between regeneration and fibrosis when the stromal niche is activated.     

Cohesion by topology: sister chromatids interlocked by DNA

Sister chromatid cohesion is coupled with chromosome replication and influences chromosome segregation and intra-S repair. Specialized proteins, the cohesins, together with other pathways contribute to tether sister chromatids. In this issue of Genes & Development, Wang and colleagues (pp. 2426-2433 demonstrate that TopoIV, a type II DNA topoisomerase, modulates cohesion in Escherichia coli, by removing interlocked DNA junctions between sister chromatids. They propose that DNA precatenanes, arising during replication fork progression, hold sister chromatids together.