胶质母细胞瘤MGMT基因启动子甲基化与蛋白表达

Objective To study the correlation of MGMT gene promoter methylation and protein expression and their regional variation in different specimens obtained from different regions within the tumor in patients with newly diagnosed glioblastoma. Methods Two to four samples in the same tumor were collected from different regions in 30 patients with newly diagnosed glioblastoma patients. In five patients among them,mutispecimens were obtained under assistance of neuronavigation system during the operation. In all samples,MGMT promoter profile were analyzed by Methylation - specific polymerase - Chain - reaction analysis, MSP ,while MGMT protein expression was detected in tissue sections by immunohistochemistry,IHC. Results MGMT promoter methylation was detected in 43. 56% (44/101) specimens. MGMT protein expression in tissue sections was assessed and scored:(1 :no or positive tumor cells < 10%, 2: ≥ 10% ≤50% ,3: > 50%) ,The rate of MGMT staining with a score 1,2,3 in all of tumor sections was 32. 67% ,43.56% ,23. 76% respectively. No significant correlation between MGMT protein expression and promoter methylation(x2 =2. 905, P =0.088) was found. The regional heterogeneity of MGMT protein expression within the same tumor was in 57% (17/30) patients ;and the regional heterogeneity of gene promoter methylation was in37%(11/30)patients. Conclusions MGMT promoter methylation is probably not the only modulating element in MGMT protein expression. The heterogeneity of MGMT protein expression and its promoter methylation in the same tumor questions their guiding significance in making therapeutic scheme for individual patients with malignant glioma in clinical practice.     

胶质母细胞瘤MGMT基因启动子甲基化与蛋白表达

Objective To study the correlation of MGMT gene promoter methylation and protein expression and their regional variation in different specimens obtained from different regions within the tumor in patients with newly diagnosed glioblastoma. Methods Two to four samples in the same tumor were collected from different regions in 30 patients with newly diagnosed glioblastoma patients. In five patients among them,mutispecimens were obtained under assistance of neuronavigation system during the operation. In all samples,MGMT promoter profile were analyzed by Methylation - specific polymerase - Chain - reaction analysis, MSP ,while MGMT protein expression was detected in tissue sections by immunohistochemistry,IHC. Results MGMT promoter methylation was detected in 43. 56% (44/101) specimens. MGMT protein expression in tissue sections was assessed and scored:(1 :no or positive tumor cells < 10%, 2: ≥ 10% ≤50% ,3: > 50%) ,The rate of MGMT staining with a score 1,2,3 in all of tumor sections was 32. 67% ,43.56% ,23. 76% respectively. No significant correlation between MGMT protein expression and promoter methylation(x2 =2. 905, P =0.088) was found. The regional heterogeneity of MGMT protein expression within the same tumor was in 57% (17/30) patients ;and the regional heterogeneity of gene promoter methylation was in37%(11/30)patients. Conclusions MGMT promoter methylation is probably not the only modulating element in MGMT protein expression. The heterogeneity of MGMT protein expression and its promoter methylation in the same tumor questions their guiding significance in making therapeutic scheme for individual patients with malignant glioma in clinical practice.     

RNA interference affects tumorigenicity and expression of insulin-like growth factor-1, insulin-like growth factor-1 receptor, and basic fibroblast growth factor-2 in rat C6 glioma cells

BACKGROUND： Human gliomas are more likely to express basic fibroblast growth factor-2 （FGF-2） insulin-like growth factor-1（IGF-1）, and IGF-1 receptor （IGF-1R） than normal brain tissue. These factors activate signal transduction systems of Ras/MAPK and PI3K/Akl, which promote glioma growth. OBJECTIVE： To utilize RNA interference （RNAi） technique to down-regulate FGF-2, IGF-1, and IGF-1R gene expression, and to investigate the effects of these genes on rat C6 glioma cells, as well as the feasibility of RNAi for treating glioma. DESIGN, TIME AND SETTING： This neurooncological, randomized, controlled, in vivo and in vitro experiment, which used RNAi methodology, was performed at the Laboratory of Molecular Biology, Institute of Biochemistry, Chinese Academy of Sciences between August 2005 and February 2008. MATERIALS： Rat C6 cell lines were purchased from Shanghai Institute of Cellular Biology Affiliated to Chinese Academy of Sciences. Small interfering RNA （siRNA） was synthesized by Shanghai GenePharma. Anti-IGF-1, anti-IGF-1R, anti-FGF-2, anti-mouse and anti-rabbit IgG G1-HRP antibodies were provided by Santa Cruz Biotechnology, USA. Four to six week-old BALB/c nude mice were purchased from the Laboratory Animal Center, Chinese Academy of Sciences. METHODS： C6 glioma cells were transfected with siRNA, which was chemically synthesized in vitro to correspond to endogenous FGF-2, IGF-1, and IGF-1R genes. The inhibition ratio of targeting mRNA expression was detected by semiquantitative RT-PCR, and protein expression was determined by Western blot analysis. C6 glioma cell proliferation was observed using a growth curve C6 glioma cell apoptosis rate and cell cycle were detected by flow cytometry. C6 glioma cell growth regression was observed by transwell migration assay. In addition, nude mouse subcutaneous tumor models were used in this study. For studying the anti-tumor effects of IGF-1 and IGF-1R siRNA, two blank control groups, with six mice each, were set up： A （2.5 μg siRNA was injected one week after C6 cells were inoculated, Le., when tumor volume reached 8 mm × 8 mm） and B （siRNA was injected at the same time with C6 cells were inoculated. To study the effects of FGF-2 siRNA, the groups consisted of a blank control group, negative control group, 2.6 μg siRNA group, 4 μg siRNA group, and 5.3 μg siRNA group, with six mice each. MAIN OUTCOME MEASURES： mRNA and protein inhibition ratio of FGF-2, IGF-1, and IGF-1 R; C6 glioma cell proliferation, apoptosis, and cycle growth arrest; C6 glioma cell growth regression and subcutaneous tumorigenicity rates. RESULTS： All siRNA constructs proved to be effective. After 48 hours, transfection of 200 nmol/L siRNA resulted in a FGF-2 or IGF-1R gene inhibition ratio 〉 80% and an IGF-1 gene inhibition ratio of approximately 70%. Protein expression levels for FGF-2, IGF-1, and IGF-1R decreased in a dose-dependent manner following siRNA transfection, with an inhibition rate 〉 85%, 60%, and 50%, respectively. C6 glioma cell proliferation and apoptosis rates increased in proportion to siRNA. The apoptosis rate of C6 glioma cells induced by FGF-2, IGF-1, and IGF-1R siRNA was 39.96%, 15.07% and 22.47%, respectively （P 〈 0.01）. Transfection of 200 nmol/L IGF or IGF-1R siRNA for 48 hours suppressed C6 glioma cell migration. At 30 days after intratumoral injection of 2.6, 4, and 5.3 tJg FGF-2 siRNA, tumor growth regression rate of FGF-2 siRNA was 56%, 67%, and 86%, respectively. The tumor growth regression rate was 71.88% and 45.71%, respectively, when IGF-1 or IGF-1R siRNA was intratumorally injected 1 week after C6 glioma cell transplantation. When IGF-1 or IGF-1 R siRNA was intratumorally injected during C6 glioma cell transplantation, the tumor growth regression rate was 78.13% and 74.29%, respectively. CONCLUSION： siRNA transfection downregulated gene expression of FGF-2, IGF-1, and IGF-1R In addition, siRNA treatment markedly suppressed glioma cell proliferation, growth, and migration, and concomitantly reduced subcutaneous tumorigenicity.     

Antisense MMP-9 RNA inhibits malignant glioma cell growth in vitro and in vivo

The matrix-degrading metalloproteinases (MMPs), particularly MMP-9, play important roles in the pathogenesis and development of malignant gliomas. In the present study, the oncogenic role of MMP-9 in malignant glioma cells was investigated via antisense RNA blockade in vitro and in vivo. TJ905 malignant glioma cells were transfected with pcDNA3.0 vector expressing antisense MMP-9 RNA (pcDNA-AS-MMP9), which significantly decreased MMP-9 expression, and cell proliferation was assessed. For in vivo studies, U251 cells, a human malignant glioma cell line, were implanted subcutaneously into 4-to 6-week-old BALB/c nude mice. The mice bearing well-established U251 gliomas were treated with intratumoral pcDNA-AS-MMP9-Lipofectamine complex (AS-MMP-9-treated group), subcutaneous injection of endostatin (endostatin-treated group), or both (combined therapy group). Mice treated with pcDNA (empty vector)-Lipofectamine served as the control group. Four or eight weeks later, the volume and weight of tumor, MMP-9 expression, microvessel density and proliferative activity were assayed. We demonstrate that pcDNA-AS-MMP9 significantly decreased MMP-9 expression and inhibited glioma cell proliferation. Volume and weight of tumor, MMP-9 expression, microvessel density and proliferative activity in the antisense-MMP-9-treated and therapeutic alliance groups were significantly lower than those in the control group. The results suggest that MMP-9 not only promotes malignant glioma cell invasiveness, but also affects tumor cell proliferation. Blocking the expression of MMP-9 with antisense RNA substantially suppresses the malignant phenotype of glioma cells, and thus can be used as an effective therapeutic strategy for malignant gliomas.     

HER-2/neu siRNA对人胶质瘤细胞增殖及相关基因表达的影响

目的 探讨HER-2/neu特异性小干扰核糖核酸(siRNA)对高表达HER-2/neu的人胶质瘤细胞系U251MG和T98G增殖的影响及其可能机制.方法 脂质体介导HER-2/neu siRNA转染体外常规培养的U251MG和T98G细胞,同时设脂质体为对照组.转染后3 d实时定量PCR和免疫印迹实验检测HER-2/neu mRNA和蛋白的表达;四甲基偶氮唑盐(MTT)比色法检测转染后3、4d细胞增殖率的变化;免疫印迹实验检测转染后3 d细胞蛋白激酶B(AKT)、磷酸化AKT、磷酸化叉头转录因子(FOXO1)、p27、Cyclin D1蛋白的表达.结果 与脂质体组比较,HER-2/neu siRNA组U251MG、T98G细胞转染后3 d HER-2/neu mRNA和蛋白的表达均下降,转染后3、4 d细胞增殖率均下降,转染后3 d细胞磷酸化AKT和磷酸化FOXO1水平降低、p27蛋白表达增多、Cyclin D1蛋白表达减少,差异均有统计学意义(P＜0.05).结论 HER-2/neu siRNA转染人胶质瘤细胞系U251MG和T98G后明显抑制细胞增殖,可能与抑制AKT/FOXO1信号通路,调控下游基因p27、Cyclin D1蛋白的表达有关.

Abstract：

Objective To investigate the effect of HER-2/neu siRNA on proliferation of human glioma cell lines U251MG and T98G which over-express HER-2/neu, and explore its mechanism.Methods Liposome-mediated HER-2/neu siRNA was transfected into human glioma cell lines U251MG and T98G;lipofectin group was established as controls. The mRNA and protein levels of HER-2/neu were detected by real-time PCR and Western blotting 3 d after the transfection. The proliferation of glioma cells was investigated using methyl thiazolyl tetrazolium (MTT) assay 3 and 4 d after the transfection. The effects of HER-2/neu siRNA on AKT/FOXO1 pathway and protein expression of p27 and Cyclin D1 were studied using Western blotting. Results HER-2/neu mRNA and protein expressions in the transfected U251MG cells were decreased to (28.833±4.174)% and (22.167±1.955)% while those in cells of the lipofectin group were (92.067±5.698)% and (96.100±1.682)%, respectively,with significant differences (P=0.000, 0.001). HER-2/neu mRNA and protein expressions of the transfected T98G cells were decreased to (28.067 ±6.165)% and (12.433 ±8.864)% while those in the untransfected cells were (96.000 ±5.110)% and (94.333 ±3.215)%, respectively, with significant differences (P=0.001, 0.008). Three d after the transfection, the rates of proliferation in the transfected T98G and U251MG cells were (58.467±5.561)% and (63.933±5.363)%, respectively;4 d after the transfection, the rates of proliferation in the transfected T98G and U251MG cells were (57.500±4.770)% and (60.167±3.253)%, respectively;an obvious decrease was noted as compared them with cells of the lipofectin group (P=0.020, 0.023, 0.021, 0.008). Cyclin Dl expression was decreased, while p27 protein expression was up-regulated in the transfected cells as compared with those in cells of the lipofectin group (P<0.05). Moreover, the levels of phosphorylated AKT and phosphorylated FOXO1 were decreased in the transfected cells as compared with those in cells of the lipofectin group (P<0.05).Conclusion The specific siRNA targeting HER-2/neu in human glioma cell lines U251MG and T98G could inhibit the cell proliferation, which might relate to the suppression of AKT/FOXO1 pathway and the regulation of expresion of thier downstream molecules such as p27 and Cyclin D1.     

环氧化酶-2抑制剂对裸鼠胶质瘤移植瘤Ang基因表达的影响

目的 探讨环氧化酶-2(COX-2)抑制剂尼米舒利(NIM)对裸鼠胶质瘤移植瘤血管生成素(Ang)基因表达的影响及意义.方法 人胶质瘤SHG44细胞接种于裸鼠皮下,建立裸鼠胶质瘤移植瘤模型,并按随机数字表法分为对照组(灌注等量生理盐水)和NIM治疗组[6 mg/(kg·d)],逆转录PCR技术检测移植瘤组织Ang-1、Ang-2mRNA表达,免疫组织化学染色测定肿瘤组织微血管密度(MVD),并绘制肿瘤生长曲线和计算肿瘤抑制率.结果 NIM可有效抑制移植瘤的生长,其抑瘤率为42.03%.NIM治疗组肿瘤组织Ang-2 mRNA表达水平(0.2032±0.0185)较对照组(0.6024±0.0289)明显降低,差异有统计学意义(P＜0.05);Ang-1 mRNA表达水平无明显改变,差异无统计学意义(P＞0.05);Ang-2/Ang-1 mRNA比值下降(0.5825±0.0621vs 1.5847±0.1948),差异有统计学意义(P＜0.05).NIM治疗组肿瘤组织MVD较对照组明显下降,差异有统计学意义(P＜0.05).结论 COX-2抑制剂NIM可下调Ang-2基因表达,改变Ang-2/Ang-1 mRNA比值,抑制肿瘤生长.

Abstract：

Objective To investigate the effect of nimesulide (NIM), a selective cyclooxygenase-2 (COX-2) inhibitor, on angiopoietins (Ang) gene expression of human glioma xenografts in nude mice and its significance. Methods Human SHG44 glioma cells were inoculated subcutaneously in 16 nude mice to establish xenograft models, and then these mouse models were randomly divided into NIM treatment group and control group. NIM (6 mg/kg) and saline were poured into the stomachs of the mice in each group, respectively, once daily for 35 d. The mRNA expressions of Ang-1 gene and Ang-2 gene in the xenografts were determined by RT-PCR. Microvessel density (MVD) in the xenografts was assessed by immunohistochemical technique. The tumor growth curve was drawn and the inhibition ratio of tumor growth was calculated. Results NIM could significantly inhibit the glioma xenografts growth with its inhibition rate reaching 42.03%. The mRNA expression of Ang-2 gene in NIM treatment group (0.2032±0.0185) was significantly lower than that in control group (0.6024±0.0289, P＜0.05), but that of Ang-1 gene showed no significant changes; therefore, the mRNA ratio of Ang-2/Ang-1 genes was decreased (0.5825±0.0621 vs. 1.5847±0.1948, P＜0.05). MVD in the xenografts of the NIM treatment group was significantly lower than that in the control group (P＜0.05). Conclusion NIM, by down-regulating the mRNA expression ofA ng-2 gene and changing the mRNA ratio of Ang-2/Ang-1 genes, can inhibit the tumor growth     

Gene expression by simian virus 40 large T antigen-induced medulloblastomas in mice

Signaling pathways known to have components with mutations in human medulloblastoma include sonic hedgehog,Wnt/beta-catenin and insulin-like growth factor.Microarray analysis was applied to examine the gene expression changes in medulloblastomas of pTet-on/pTRE-SV40Tag transgenic mice.Altogether,14 112 genes were detectable,including 152 genes with significantly different expression levels.These genes were associated with immunity,the cell cycle,signal transduction,cytoskeleton and metabolism.To further confirm the microarray data,real-time polymerase chain reactions were used to examine the expression changes of genes related to sonic hedgehog,Wnt/beta-catenin and insulin-like growth factor signal pathways.Immunohistochemistry detected insulin receptor substrate-1 in the nuclei of brain tumor tissue cells from pTet-on/pTRE-SV40Tag transgenic mice,suggesting that SV40 large T antigen may activate the insulin-like growth factor signal pathway to promote tumorigenesis.     

Exogenous p16 gene therapy combined with X-ray irradiation suppresses the growth of human glioma cells

In this study, we infected human glioma U251 cells with a replication-defective recombinant adeno-virus carrying the p16 gene. This adenovirus constructed was able to transfect exogenous p16 into the human glioma cells efficiently, and direct a high level of p16 protein expression. Tumor-inhibition experiments demonstrated that treatment with the adenovirus-p16 significantly inhibited the growth of glioma cells in vitro as well as the in vivo development of tumors in nude mice bearing a brain glioma. The combination of adenovirus-p16 gene treatment and X-ray irradiation resulted in a greater inhibition of tumor growth. Adenovirus-mediated p16 gene therapy conferred a significant antitumor effect against human glioma cells both in vitro and in vivo, and that there was a synergistic effect when X-ray irradiation was also used.     

T cells promote the regeneration of neural precursor cells in the hippocampus of Alzheimer＇s disease mice

Alzheimer's disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1–42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzheimer's disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines(interleukin-2, interferon-γ) and hippocampal microglia-related cytokines(interleukin-1β, tumor necrosis factor-α) correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer's disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer's disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer's disease.     

Phosphoinositide-3-kinase regulatory subunit 4 participates in the occurrence and development of amyotrophic lateral sclerosis by regulating autophagy

The development of amyotrophic lateral sclerosis(ALS)may be related to the abnormal alterations of multiple proteins.Our previous study revealed that the expression of phosphoinositide-3-kinase regulatory subunit 4(PIK3R4)was decreased in ALS.However,the role of PIK3R4 in ALS pathogenesis remains unknown.This study was the first to find that transfection of PC12 cells with small interfering RNA against the PIK3R4 gene significantly decreased the expression levels of PIK3R4 and the autophagy-related proteins p62 and LC3.Additionally,in vivo experiments revealed that the PIK3R4 protein was extensively expressed in the anterior horn,posterior horn,central canal,and areas surrounding the central canal in cervical,thoracic,and lumbar segments of the spinal cord in adult mice.PIK3R4 protein was mainly expressed in the neurons within the spinal lumbar segments.PIK3R4 and p62 expression levels were significantly decreased at both the pre-onset and onset stages of ALS disease in Tg(SOD1*G93A)1 Gur mice compared with control mice,but these proteins were markedly increased at the progression stage.LC3 protein expression did not change during progression of ALS.These findings suggest that PIK3R4 likely participates in the prevention of ALS progression.This study was approved by the Ethics Committee for Animal Care and Use of Jiangxi Provincial People’s Hospital,Affiliated People’s Hospital of Nanchang University(approval No.2020025)on March 26,2020.     

特异性小干扰RNA沉默Polo样激酶1基因表达对恶性胶质瘤细胞增殖的影响

目的 探讨Polo样激酶1(PLK1)基因对胶质瘤细胞增殖的影响和可能机制. 方法 根据PLK1基因特点,设计并用化学方法合成了5个小干扰核糖核酸分子(siRNA)(P1、P2、P3、P4和P5).以这5个siRNA转染人胶质瘤TJ905细胞后.分别采用荧光实时定量RT-PCR和Western blot检测PLK1 mRNA和蛋白表达水平.分别采用MTT法和Western blot方法检测癌细胞增殖和增殖细胞核抗原(PCNA)蛋白水平,用TRA-.ELISA方法检测胶质瘤细胞端粒酶活性. 结果 所设计的5个siRNA均能明显抑制胶质瘤TJ905细胞PLK1 mRNA水平,以P4效果最好.以P4转染处理胶质瘤细胞后与脂质体对照组比较,PLK1基因mRNA水平和蛋白水平明显下调,差异有统计学意义(P均=0.000).MTT结果显示.与脂质体对照组比较P4 siRNA转染组癌细胞生长明显受到抑制,且呈浓度依赖性(r=0.868,P=0.000).Western blot结果显示,与脂质体对照组比较P4 siRNA转染组PCNA蛋白水平明显下降,差异有统计学意义(F=181.36,P=0.000).TRAP-ELISA结果显示,与脂质体对照组比较P4 siRNA转染组胶质瘤细胞端粒酶活性明显受到抑制,且呈浓度和时间依赖性(P=0.000). 结论 PLK1基因对胶质瘤细胞增殖具有重要的调控作用;以PLK1 siRNA转染处理胶质瘤细胞,可明显抑制胶质瘤细胞的恶性增殖,其机制可能与抑制端粒酶活性有关.     

RNAi抑制STAT3对胶质瘤干细胞的生长抑制作用

目的 建STAT3的RNAi载体干扰STAT3的表达,在体内外研究对胶质瘤干细胞的影响。方法 构建STAT3基因shRNA的腺病毒表达载体,感染人胶质瘤干细胞。采用RT -PCR、Western blot检测STAT3基因的干扰效果,用MTT和流式细胞仪检测干细胞的增殖、凋亡,并观察对荷瘤裸鼠的影响。结果转染重组腺病毒Ad - STAT3 siRNA后,胶质瘤干细胞的STAT3的mRNA表达率为(41.5±7.3)％,蛋白表达率为（31.2±6.4）％,细胞的增殖受到抑制,凋亡率为(23.8±6.1)％,同时荷瘤裸鼠的肿瘤生长受到抑制,生存期延长。结论重组腺病毒介导的STAT3 RNAi可显著抑制靶基因的表达与活化,显著抑制胶质瘤干细胞的生长功能,为基于胶质瘤干细胞的功能治疗提供了基础理论。     

RNAi对细胞因子信号转导抑制因子1在内皮细胞中表达的沉默作用

背景：利用RNAi技术引发细胞因子信号转导抑制因子1沉默可促进神经内分泌肿瘤细胞的凋亡,然而对于内皮细胞是否有类似的作用,目前尚不清楚。 目的：实验拟验证内皮细胞中是否有细胞因子信号转导抑制因子1表达,并在所设计的siRNA中,筛选出1对对细胞因子信号转导抑制因子1沉默效率最高的siRNA。 设计、时间及地点：随机对照,体外细胞学实验,于2007-12/2008-06在南昌大学医学院第二附属医院所属的江西省分子医学重点实验室完成。 材料：人脐静脉内皮细胞由南京凯基生物公司提供。 方法：设计并化学合成4对靶向细胞因子信号转导抑制因子1的siRNA：siRNA-1、siRNA-2、siRNA-3、siRNA-4。培养人脐静脉内皮细胞,利用RT-PCR检测人脐静脉内皮细胞是否有细胞信号转导抑制因子1表达。将带有荧光标记的阴性对照siRNA配制成25,50,75,100 nmol/L的4组,利用脂质体转染细胞,并在荧光倒置显微镜下观察转染效率,对比得出有最佳转染效率的浓度。然后,实验根据不同的处理因素分成8组：siRNA-1、siRNA-2、siRNA-3、siRNA-4和阳性对照组、阴性对照组、转染试剂组、空白对照组4个对照组。将均为有最佳转染效率浓度的各组siRNA转染细胞,48 h后提取RNA。 主要观察指标：利用RT-PCR测定细胞因子信号转导抑制因子1 mRNA的相对表达水平。 结果：人脐静脉内皮细胞高表达细胞因子信号转导抑制因子1。siRNA在50 nmol/L时有较高的转染效率。4对siRNA干扰后,细胞因子信号转导抑制因子1 mRNA的表达水平与阴性对照、转染试剂组和空白对照组相比明显下调(P < 0.05),与阳性对照组相比显著下调(P < 0.01),其中siRNA-3的沉默效率最高(P < 0.05),阴性对照、转染试剂组和空白对照组与阳性对照组相比明显下调(P < 0.05),阴性对照、转染试剂组和空白对照组之间差异无显著性意义(P > 0.05)。 结论：内皮细胞中存在细胞因子信号转导抑制因子1表达。RNAi抑制细胞因子信号转导抑制因子1在内皮细胞中的表达,实验筛选出1对沉默效率最高的siRNA。     

Nf1基因沉默促进人脑血管内皮细胞的增殖

目的抑制1型神经纤维瘤病(NF1)发病基因Nf1在人脑血管内皮细胞(HBMECs)中的表达并检测HBMECs增殖改变情况,以研究NF1相关脑血管病发病机制。方法设计并合成3对Nf1基因小干扰RNA(siRNA)及其阴性对照;使用脂质体转染法将siRNA转染进HBMECs,通过实时荧光定量PCR(Real-time PCR)及Western blot法分别检测Nf1基因mRNA和蛋白质表达情况。将筛选出的具有最佳Nf1基因沉默效应的siRNA转染进HBMECs,并设置阴性对照,使用细胞计数试剂盒8(CCK8)法与细胞计数法检测细胞增殖情况。结果3对siRNA均具有一定的Nf1基因沉默效应,其中siRNA C基因沉默效应最佳,Nf1基因mRNA相对转录水平是对照组的(58.65±0.62)%,神经纤维瘤蛋白(neurofibromin)的相对表达量为对照组的(29.447.10)%,差异均有统计学意义(P<0.01)。CCK8法与细胞计数法结果均显示Nf1基因沉默后HBMECs 5d中有4d实验组相对细胞数多于对照组(P<0.05)。结论干扰HBMECs Nf1基因后,其增殖活性增强,这可能是NF1相关脑血管病的发病机制之一。     

连接蛋白基因对人脑胶质瘤细胞生长抑制作用的实验研究

目的:探讨连接蛋白(Ｃｘ)基因对人脑胶质瘤细胞生长的抑制作用。方法:以脂质体介导将Ｃｘ４３ｃＤＮＡ导入Ｃｘ４３表达缺失的ＴＪ９０５人胶质母细胞瘤细胞;Ｎｏｒｔｈｅｒｎ杂交、原位杂交及免疫组化检测Ｃｘ４３ｍＲＮＡ及蛋白表达;ＭＴＴ法和ＡｇＮＯＲ染色检测细胞增殖;ＴＵＮＥＬ法测细胞凋亡。结果:转染后ＴＪ９０５细胞有Ｃｘ４３ｍＲＮＡ及蛋白表达,高表达的克隆增殖明显下降。细胞凋亡不增加。结论:Ｃｘ４３基因可能成为恶性胶质瘤基因治疗的优选靶之一。     

化学合成siRNA抑制原代皮层神经元NgR的表达

目的筛选能有效抑制神经元NgR表达的siRNA序列。方法根据siRNA靶序列设计原则,设计并化学合成针对大鼠NgR基因编码区的siRNA三对,并以一对无关序列的寡核苷酸作为阴性对照。原代培养的大鼠皮层神经元分为5组:siRNA-1组、siRNA-2组、siRNA-3组、无关序列组、非转染组,用阳离子脂质体TransMessenger Transfection Reagent转染。转染后48h行RT-PCR和免疫细胞化学检测NgR表达水平的变化。结果转染48h后,与序列2、3和无关序列转染以及未转染的细胞相比,序列1转染的神经元NgR mRNA水平明显下降,并且其NgR抗体免疫荧光染色的荧光强度也明显减弱。结论化学合成siRNA能有效地抑制原代皮层神经元NgR的表达。     

RNA干扰敲低Wnt2的表达抑制U251细胞生长的体内外研究

目的 在体内外研究转染靶向Wnt2的siRNA对U251细胞的抑制效果.方法 向U251细胞转染靶向Wnt2的siRNA后,免疫印记检测转染后Wnt2及相关蛋白表达,MTT检测细胞增殖,annexin标记细胞凋亡,流式细胞仪检测细胞周期分布,鼠尾胶3D生长实验检测细胞侵袭能力的变化.建立裸鼠胶质瘤皮下动物模型,瘤内注射Wnt2 siRNA观察肿瘤生长情况.结果 转染Wnt2siRNA后,U251细胞的Wnt2、frizzled2、磷酸化GSK-3β、β-catenin等表达降低,细胞增殖受抑,凋亡率升高,细胞阻滞于G0/G1期.体内研究发现转染靶向Wnt2的siRNA后,裸鼠皮下肿瘤的生长速度缓慢,相应的蛋白表达降低.结论 转染靶向Wnt2的siRNA可有效敲低该基因在U251细胞内的表达,从而抑制了胶质瘤细胞生长,具有潜在的治疗前景.     

Notch信号通路与胶质瘤细胞上皮间充质转化的相关性

目的 探讨Notch信号通路与胶质瘤细胞上皮间充质转化的关系.方法 采用免疫磁珠法从人脑胶质瘤组织分离脑胶质干细胞,进行体外培养,使用免疫荧光技术鉴定细胞;构建Notch-1基因的RNA干扰反转录病毒载体(pSiRNA-Notch-1),试验分为3组,空白对照组(不转染质粒)、阴性对照组(转染空白质粒)和干扰组(转染pSiRNA-Notch-1),观察3组细胞增殖、分化,采用RT-PCR和Western blot检测Notch-1和Hes-1 mRNA和蛋白表达.结果 干扰组培养第7天细胞增殖及细胞分化吸光度值(A)分别为(1.332±0.614)和(1.203±0.783),明显低于空白对照组和阴性对照组(P<0.05);细胞增殖培养3 d后,干扰组Notch-1和Hes-1 mRNA和蛋白相对表达量分别为(0.189±0.021)和(0.301±0.121),(0.422±0.022)和(0.091±0.032),明显低于空白对照组和阴性对照组(P<0.05);细胞分化培养3 d后,干扰组Notch-1和Hes-1 mRNA和蛋白相对表达量分别为(0.253±0.071)和(0.192±0.043),(0.178±0.022)和(0.101±0.012),明显低于空白对照组和阴性对照组(P<0.05).结论 Notch信号通路在胶质瘤细胞增殖分化过程中有重要作用,其中Notch-1和Hes-1可能参与了增殖、分化的调控,需进一步研究.     

FasL基因治疗移植于裸鼠的人脑胶质母细胞瘤的实验研究

目的 :探讨FasL基因在体内诱导胶质瘤细胞凋亡和抑制增殖的作用。方法 :在裸鼠皮下种植Fas表达阳性的人脑胶质母细胞瘤细胞系TJ90 5 ,成瘤后 ,利用脂质体介导FasL基因瘤内治疗 ,在 3 9d观察期间 ,用千分尺测量肿瘤生长 ,最终取出肿瘤 ,用原位杂交 ,免疫组化鉴定FasL基因和蛋白的表达 ,应用TUNEL法检测细胞凋亡 ,Ki 67免疫组化检测细胞增殖。结果 :FasL基因瘤内注射观察 3 9d后 ,治疗组瘤体积明显小于对照组 (P <0 0 1) ,肿瘤组织细胞内FasL基因表达增加 ,凋亡细胞数增多 ,细胞增殖率降低。结论 :FasL基因对Fas表达阳性胶质瘤有治疗作用。     

Effects of Raf-1 siRNA on human cerebral microvascular endothelial cells: a potential therapeutic strategy for inhibition of tumor angiogenesis

The serine/threonine kinase Raf-1 is involved in the regulation of tumor cell survival, proliferation and metastasis formation, and has therefore emerged as a promising target for cancer therapy. In addition, Raf-1 activity mediates proliferation of endothelial cells thereby promoting angiogenesis and invasive growth of various tumors, including highly vascularized malignant glioblastoma. The aim of this study was to evaluate the effects of small inhibitory RNA (siRNA) directed against Raf-1 on viability, proliferation and motility in glioma cells and cerebral endothelial cells. Half-quantitative RT-PCR and Western blotting revealed efficient siRNA-mediated Raf-1 down regulation in glioma cells (U373, U251) and in human cerebral microvascular endothelial cells (HCMEC). Surprisingly, Raf-1 gene silencing failed to affect cell survival, proliferation or migration activity in the glioblastoma cell lines. In HCMEC, however, pronounced decrease of cell survival and significant inhibition of tube formation was achieved by Raf-1 siRNA compared to non-functional siRNA or vehicle controls. In conclusion, Raf-1 silencing appears as a potential therapeutic strategy to inhibit brain tumor angiogenesis and thereby outgrowth of highly vascularized glioblastoma multiforme, whereas direct cytotoxic effects of Raf-1 knockdown in tumor cells may vary.