siRNA干扰PDLIM1表达抑制胶质瘤细胞U87迁移与侵袭

目的 研究人PDZ和LIM域蛋白1(PDLIM1)特异性siRNA对人胶质母细胞瘤U87细胞系迁移、侵袭能力的影响,并对其相关机制进行初步探讨.方法 用小RNA干扰技术下调U87细胞PDLIM1,用荧光实时定量Real-time PCR技术验证siRNA干扰效率;采用细胞划痕实验检测细胞迁移能力,采用Transwell实验检测细胞侵袭能力;用Western blot法检测细胞上皮间质转化(EMT)相关蛋白表达情况,并探讨相关机制.结果 经PD-LIM1-siRNA干扰后,胶质瘤U87细胞中PDLIM1在mRNA水平显著下调(P<0.001);与对照组相比,迁移和侵袭能力被显著抑制(P<0.001);PDLIM1基因表达下调后,U87细胞中EMT相关蛋白N-cadherin、β-catenin、Slug下调.结论 PDLIM1通过EMT相关转录因子Slug调节N-cadherin、β-catenin蛋白表达,是其调节胶质瘤U87细胞迁移及侵袭能力的可能机制之一.     

微丝在体外培养四种不同细胞表达的形态观察

【目的】探讨微丝在4种不同细胞内的形态分布。【方法】体外培养人胃低分化粘液腺癌(MGC80 3)细胞系、人肝癌(SMMC772 1)细胞系、原代培养人皮肤成纤维细胞(HSF)和大鼠骨髓间充质干细胞(MSC) ;用考马斯亮蓝显示四种细胞内的微丝,通过光学显微镜观察微丝分布的状态。【结果】MGC80 3细胞系和人肝癌SMMC772 1细胞系内,微丝较细且均匀分布,原代培养的HSF和MSC细胞内微丝较为粗大,分布不均匀。【结论】微丝分布与细胞的粘附状态和细胞形态有密切关系。     

CCND1表达沉默促进胶质母细胞瘤细胞株对替莫唑胺的敏感性

目的 利用已构建的CCND1表达沉默及过表达的人源性胶质母细胞瘤细胞株SHG-44,筛选能够与CCND1协同抑制胶质母细胞瘤细胞增殖的化学治疗药物.方法 用蛋白质印迹法检测CCND1表达沉默及过表达的人源性胶质母细胞瘤细胞株SHG-44中多药耐药基因MDR1的表达产物P-糖蛋白(P-gp)及凋亡因子Bcl-2、Caspase-3的表达.使用卡莫司汀(BCNU)、洛莫司汀(CCNU)、替莫唑胺(TMZ)3种化学治疗药物分别处理CCND1过表达或表达沉默的SHG-44细胞,筛选能够与CCND1表达沉默协同抑制肿瘤细胞生长的化学治疗药物,并在人源性胶质母细胞瘤细胞株系U251中进一步验证.结果 蛋白质印迹结果示CCND1表达沉默能够下调P-gp、Bcl-2的表达,上调Caspase-3的表达(P均＜0.01).BCNU (0.05、0.25 μg/mL)、CCNU(20、80 μg/mL)处理CCND1过表达或表达沉默的SHG-44细胞的第2、3、4、5天时,细胞生长曲线的差异均无统计学意义;而在药物处理后细胞培养的第4、5天,CCND1表达沉默SHG-44细胞的生长受到TMZ(9.1μg/mL)的抑制作用较亲代SHG-44细胞强(P＜0.05).U251细胞实验证实CCND1表达沉默促进TMZ的化学治疗敏感性.结论 CCND1表达沉默联合TMZ较两者单独作用能更有效地抑制人源性胶质母细胞瘤细胞株SHG-44的增殖,提示CCND1可能参与TMZ化学治疗耐药机制.     

沉默缺氧诱导因子对人胶质瘤SHG44细胞糖酵解及细胞增殖的影响

目的探讨沉默缺氧诱导因子(hypoxia-inducible factor-1alpha,HIF-1α)对缺氧状态人胶质瘤SHG44细胞糖酵解及细胞增殖的影响及机制。方法用氯化钴(CoCl2)模拟缺氧,并应用小分子RNA干扰(siRNA)技术沉默HIF-1α基因表达。将细胞分成4组:正常培养组、缺氧培养组、阴性对照组和siRNA干扰组。各组又分为常糖组(2 g/L)和高糖组(5 g/L)。Real-time PCR、Western blot法分别检测肿瘤细胞HIF-1α和糖酵解酶的mRNA及蛋白表达;生物发光法检测细胞内ATP水平;激光共聚焦显微镜检测细胞线粒体膜电位;MTT法检测细胞增殖;流式细胞技术检测细胞凋亡、坏死及细胞内活性氧的变化。结果①缺氧条件下,HIF-1αsiRNA干扰沉默HIF-1α基因的效率达到71%。②缺氧培养组HIF-1α和糖酵解酶的mRNA和蛋白表达高于正常培养组(P<0.05),细胞内ATP水平减少、细胞坏死和凋亡均增加,而细胞增殖能力明显增强(P<0.05),同时线粒体膜电位升高(P<0.05)。③siRNA干扰组HIF-1α和糖酵解酶的表达量低于缺氧培养组、阴性对照组(P<0.05);ATP水平低于缺氧培养组,细胞增殖率下降(P<0.05),细胞坏死率高于缺氧培养组(P<0.05),线粒体膜电位恢复。结论缺氧诱使肿瘤细胞表达HIF-1α,促进肿瘤恶性进展;siRNA干扰沉默HIF-1α能加重缺氧状态下SHG44细胞的生长抑制和坏死,其机制与抑制糖酵解、恢复线粒体功能有关。     

抑制OGG1增加替莫唑胺对神经胶质瘤细胞U251的敏感性及机制探讨

目的探讨8-羟基鸟嘌呤DNA糖苷酶（OGG1）对脑神经胶质瘤细胞增殖及替莫唑胺(temozolomide,TMZ化疗敏感性的影响。方法采用光镜、CCK-8、活性氧（ROS）检测试剂盒DCFH-DA探针、Western blot观察及检测替莫唑胺处理后神经胶质瘤细胞的形态、细胞活力、细胞内活性氧水平及OGG1蛋白的表达水平; Real time-PCR技术检测OGG1m RNA干扰率; OGG1下调后,U251的细胞存活率及OGG1蛋白的表达水平。结果与对照组相比,替莫唑胺处理后,U251细胞的生存能力显著下降（P<0.05）,ROS水平显著增加（P<0.05）,OGG1蛋白表达水平显著降低（P<0.05）,当替莫唑胺剂量为100μmol/L时,对U251细胞的损伤最大（P<0.01）。当OGG1 si RNA干扰U251细胞OGG1后,OGG1 m RNA及OGG1蛋白的表达水平降低（P<0.05）,而利用低剂量的替莫唑胺对U251细胞处理时,细胞存活率显著降低（P <0.05）。结论 OGG1通过ROS通路,介导替莫唑胺对神经胶质瘤细胞U251的氧化损伤,OGG1抑制可增强神经胶质瘤细胞对TMZ的化疗敏感性。     

二甲双胍增强胶质瘤细胞对替莫唑胺的化疗敏感度的分子机制研究

目的 本研究探讨了二甲双胍对胶质瘤细胞替莫唑胺(TMZ)化疗敏感度的影响以及分子机制研究.方法 TMZ联合二甲双胍药物处理胶质瘤细胞,qRT-PCR及Western blot法检测蛋白表达;细胞免疫荧光检测HIF-1α 细胞定位和表达;葡萄糖和乳酸检测试剂盒检测葡萄糖消耗量和乳酸释放量;Annexin V-FITC/P...     

脑神经胶质瘤细胞癌胚抗原相关细胞黏附分子1对替莫唑胺化疗敏感性的作用及其机制研究

目的 探究脑神经胶质瘤细胞癌胚抗原相关细胞黏附分子1(CEACAM1)表达对替莫唑胺（TMZ）化疗敏感性的作用及其机制研究。方法 体外培养TMZ耐药人脑神经胶质瘤细胞系U251/TMZ细胞,采用空载质粒或siRNA转染U251/TMZ细胞,分为空载组、TMZ组、siRNA组及siRNA+TMZ组,转染48 h后,GFP荧光检测细胞转染效率。采用实时荧光定量聚合酶链反应检测细胞CEACAM1 mRNA的表达,MTT法检测U251/TMZ细胞增殖,流式细胞术检测细胞凋亡,酶联免疫吸附试验和Western blotting检测Wnt/β-catenin通路相关蛋白的表达。结果 与空载组比较,siRNA组、siRNA+TMZ组CEACAM1 mRNA相对表达量降低（P <0.05）,细胞增殖抑制率、细胞凋亡率升高（P <0.05）,Wnt1蛋白表达水平、β-catenin及c-myc蛋白相对表达量降低（P <0.05）;与TMZ组比较,siRNA组、siRNA+TMZ组CEACAM1 mRNA相对表达量降低（P <0.05）,细胞增殖抑制率、细胞凋亡率升高（P <...     

低氧诱导因子-1α在人脑胶质瘤中的表达及意义

目的 研究低氧诱导因子-1α(HIF-1α).在不同病理级别人脑胶质瘤中的表达情况,探讨其与病理级别问的关系.方法 收集67例人脑胶质瘤标本以及10例行内减压术切除的正常脑组织标本,采用免疫组织化学方法研究HIF-1α在不同病理级别胶质瘤及正常脑组织中的表达情况.结果 HIF-1α阳性表达率在Ⅲ、Ⅳ胶质瘤中显著高于Ⅱ级胶质瘤,分别为72.7%、80.0%、36.0%,在正常脑组织中未见阳性表达,随着病理级别的增高,HIF-1α的表达阳性强度也相应增加(r=0.518).结论 HIF-1α在人脑胶质瘤中存在高度表达,其阳性表达率及表达阳性强度随着病理级别增加而上升.     

沉默高迁移率族蛋白B1对胶质母细胞瘤细胞恶性生物学行为的抑制

目的 探讨高迁移率族蛋白B1(high mobility group protein B1,HMGB1)在胶质母细胞瘤样本中的高表达对于胶质母细胞瘤侵袭能力及替莫唑胺治疗的影响.方法 利用癌症和肿瘤基因图谱(the cancer genome atlas,TCGA)数据库中319例样本的HMGB1测序数据进行差异表达及...     

低氧诱导因子-1αsiRNA对HaCaT细胞诱导型一氧化氮合酶表达的影响

目的:观察低氧诱导因子-1α( hypoxia inducible factor-1α,HIF-1α)RNA干扰对低氧条件下永生化角质形成细胞株HaCaT细胞HIF-1α和诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达的影响.方法:将HaCaT细胞分为4组:常氧对照组...     

Prognostic factors influencing clinical outcomes of glioblastoma multiforme

Background Glioblastoma multiforme （GBM） is the most malignant kind of astrocytic tumors and is associated with a poor prognosis. In this retrospective study, we assessed the clinical, radiological, genetic molecular and treatment factors that influence clinical outcomes of patients with GBM. Methods A total of 116 patients with GBM who received surgery and radiation between January 2006 and December 2007 were included in this study. Kaplan-Meier survival analysis and Cox regression analysis were used to find the factors independently influencing patients＇ progression free survival （PFS） time and overall survival （OS） time. Results Age, preoperative Karnofsky Performance Scale （KPS） score, KPS score change at 2 weeks after operation, neurological deficit symptoms, tumor resection extent, maximal tumor diameter, involvement of eloquent cortex or deep structure, involvement of brain lobe, Ki-67 expression level and adjuvant chemotherapy were statistically significant factors （P 〈0.05） for both PFS and OS in the univariate analysis. Cox proportional hazards modeling revealed that age 〈50 years, preoperative KPS score 〉80, KPS score change after operation 〉0, involvement of single frontal lobe, non-eloquent area or deep structure involvement, low Ki-67 expression and adjuvant chemotherapy were independent favorable factors （P 〈0.05） for patients＇ clinical outcomes. Conclusions Age at diagnosis, preoperative KPS score, KPS score change at 2 weeks postoperation, involvement of brain lobe, involvement of eloquent cortex or deep structure, Ki-67 expression level and adjuvant chemotherapy correlate significantly with the prognosis of patients with GBM.     

Glioblastoma stem cells resistant to temozolomide-induced autophagy

Background Recent studies have demonstrated the existence of a small fraction of cells with features of primitive neural progenitor cells and tumor-initiating function in brain tumors. These cells might represent primary therapeutic target for complete eradication of the tumors. This study aimed to determine the resistant phenotype of glioblastoma stem cells （GSCs） to temozolomide （TMZ） and to explore the possible molecular mechanisms underlying TMZ resistance. Methods Freshly resected glioblastoma specimen was collected and magnetic isolation of GSCs was carried out using the Miltenyi Biotec CD133 Cell Isolation kit. The cytotoxic effect of TMZ on CD133^＋ and CD133^- glioblastoma cells was determined by using the 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide （MTT） assay. Autophagy-related proteins （Beclin-1, LC3 and Atg5） and cleaved caspase-3 （p17） were analyzed by Western blotting. Immunofluorescent staining was used to detect Atg5, glial fibrillary acidic protein （GFAP） and CD133 expression in glioblastoma cells. Statistical analysis was carried out using SPSS 10.0 software. For all tests, the level of statistical significance was set at P 〈0.05. Results CD133^＋ glioblastoma ceils exhibited neurosphere-like growth in vitro and high expression of CD133 stem cell marker. The growth-inhibiting rate in CD133- glioblastoma cells treated with 5 or 50 pmol/L TMZ was significantly higher than that in CD133^＋ glioblastoma cells （（14.36±3.75）% vs （2.54±1.36）% or （25.95±5.25）% vs （2.72±1.84）%, respectively, P 〈0.05）. Atg5, LC3-11 and Beclin-1 levels were significantly lower in CD133^＋ glioblastoma cells than those in autologous CD133^- cells after TMZ treatment （P 〈0.05）. Caspase-3 was mildly activated only in CD133^- glioblastoma cells after exposure to TMZ （P 〈0.05）. Immunofluorescent staining revealed elevated expression of Atg5 in GFAP^＋ cells following TMZ treatment. Conclusions The GSCs display strong capability of tumor＇s resistance to TMZ. This resistance is probably contributed by the CD133^＋ cells with down-regulation of autophagy-related proteins. Future treatment should target this small population of cancer stem cells in tumors to improve survival of patients.     

Relationship between magnetic resonance imaging and molecular pathology in patients with glioblastoma multiforme

Background  Glioblastoma multiforme (GBM) is the most common and lethal primary brain tumor in adults. Magnetic resonance imaging (MRI) is routinely used in the diagnosis, characterization and clinical management of GBM. The diagnosis and treatment of GBM is largely guided by histopathology and immunohistochemistry. This study aimed to identify the relationship between magnetic resonance features and molecular pathology of GBM.

Methods  MRI images of 43 glioblastoma patients were collected. Four imaging features, degree of edema, contrast tumor enhanced/T2 ratio, multiple lesions and tumor across the midline, were selected to identify their relationship with P53, Ki-67 and O⁶-methylguanine-DNA methltransferase (MGMT) expression in patients with GBM. The relationship between imaging features and molecular pathology was studied by chi-square test using the software SPSS 13.0.

Results  High expression of P53 was found correlated with low contrast tumor enhanced/T2 ratio, low expression of Ki-67 was correlated with multiple lesions and high expression of KI-67 may be related with tumor across the midline, low expression of MGMT was correlated with edema.

Conclusion  Some MRI features such as the degree of edema, contrast tumor enhanced/T2 ratio, multiple lesions and tumor acrossing the midline are correlated with P53, Ki-67 and MGMT of GBM.

     

HMGA1在由胶质母细胞瘤细胞株U251分得的胶质瘤干细胞中的表达

目的分析人类胶质母细胞瘤(glioblastoma multiforme,GBM)细胞株U251和由此分离的胶质瘤干细胞中HMGA1的差异性表达。方法用MACS柱从U251中分离出表达表面标志物CD133的胶质瘤干细胞(glioblas-toma stem cells,GSCs),并用免疫荧光技术和流式细胞分析法对其进行分析。用实时反转录酶-聚合酶链反应技术(real-time PCR,RT-PCR)和蛋白质印迹技术分别探测到两类细胞的HMGA1基因在转录和翻译水平上表达的不同。结果从U251中分离出GSCs,U251中的GSCs约为0.32%。在GSCs中,HMGA1在转录和翻译水平上分别为U251蛋白的(6.13±0.25)倍和(2.75±0.99)倍。结论相比于U251,HMGA1在GSCs是过度表达的。HMGA1的过度表达可能与体内肿瘤干细胞的恶性扩增、侵袭和分化密切相关。HMGA1基因可望成为胶质母细胞瘤的一种生物标记物和治疗的靶向目标。     

Relationship between MRI features and miRNA gene expression in patients with glioblastoma multiforme

BACKGROUND: Magnetic resonance imaging (MRI) is commonly utilized as the part of the diagnostic workup for the clinical diagnosis of glioblastoma multiforme (GBM), further guiding the clinical treatment of this aggressive cancer. Recent research has shown that micro RNA’s (miRNAs) may act as oncogenes, or in some cases, tumor suppressor genes that in turn may reflect the genotypic features of GBM. METHODS: In order to identify the relationship between the radiographic findings of MRI with those identified changes in miRNA gene expression of GBM, we reviewed the MRI images of GBM patients and compared them to the identified miRNA expression profiles utilizing microarray analysis of paired GBM tumor samples. We chose five MRI imaging features: 1. contrast tumor enhanced/necrosis ratio, 2. contrast tumor enhanced/T2 ratio, 3. multiple lesions, 4. hemorrhage and 5. necrotic volume. The relationship between these five imaging features and miRNA expression was studied using Significance Analysis of Microarrays (SAM) analysis. RESULTS: We found that the expression of miRNA’s hsa-miR-892b, hsa-miR-892a, hsa-miR-888 was inversely correlated with a enhanced/necrosis ratio ≥ 1. The miRNA’s hsa-miR-95, hsa-miR-498 and hsa-miR-1300 were associated with a contrast tumor enhanced/T2 ratio ≥ 1. The miRNA’s hsa-miR-612,hsa-miR-524-3 and hsa-miR-1282 were associated with multiple lesions identified on MRI and the expression of miR-221 was associated with hemorrhage in GBM. The expression of miR-let-7, including miR-let-7f, miR-let-7i, miR-let-7f-1*, were down-regulated in the hemorrhage group. The gene expression of of miRNA’s hsa-miR-140-5p, hsa-miR-30e and hsa-miR-301a was relatively low when compared with the larger necrotic volume group as identified by MRI. CONCLUSION: The miRNA gene expression profiles correlate with several select MRI features of patients with GBM. Further analysis of key imaging features of MRI with correlation with miRNA gene expression patterns may help to guide treatment decisions based upon these unique correlative profiles of GBM.     

Effect of intensity-modulated radiotherapy versus three-dimensional conformal radiotherapy on clinical outcomes in patients with glioblastoma multiforme

Background Few studies were reported on the comparison of clinical outcomes between intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) in the treatment of gli...     

吐温-80合并温热对人多型性胶质母细胞瘤细胞系BT-325的诱导分化

目的　研究吐温 - 80合并温热对BT - 32 5人多型性胶质母细胞瘤细胞系BT - 32 5细胞的分化诱导效应。方法应用免疫细胞化学等方法 ,观察BT - 32 5细胞经吐温 - 80合并 4 1℃温热作用后 (2 4小时 )胶质纤维酸性蛋白 (GFAP)基因的表达 ;并通过克隆形成率及测定细胞生长曲线等方法观察细胞恶性增殖能力。结果　 (1)BT - 32 5细胞经吐温 - 80合并温热作用后 ,出现明显的分化特征 :胞体显著增大 ,贴壁明显 ,细胞突起增多 ,与周围细胞接触 ,且有接触抑制现象 ;GFAP的含量明显增加 ;(2 )克隆形成率显示合并作用后克隆形成数减少 ,与对照组比较有显著差异 (P <0 .0 1)。结论　吐温 - 80合并 4 1℃温热作用可显著抑制BT - 32 5细胞恶性增殖 ,并有促进GFAP表达的效应 ,显示吐温 - 80合并温热对BT - 32 5细胞的分化有诱导效应     

Decoupling of DNA damage response signaling from DNA damages underlies temozolomide resistance in glioblastoma cells

Glioblastoma multiforme （GBM） is the most aggressive primary brain tumor in adults.Current therapy includes surgery,radiation and chemotherapy with temozolomide （TMZ）.Major determinants of clinical response to TMZ include methylation status of the O6-methylguanine-DNA methyltransferase （MGMT） promoter and mismatch repair （MMR） status.Though the MGMT promoter is methylated in 45% of cases,for the first nine months of follow-up,TMZ does not change survival outcome.Furthermore,MMR deficiency makes little contribution to clinical resistance,suggesting that there exist unrecognized mechanisms of resistance.We generated paired GBM cell lines whose resistance was attributed to neither MGMT nor MMR.We show that,responding to TMZ,these cells exhibit a decoupling of DNA damage response （DDR） from ongoing DNA damages.They display methylation-resistant synthesis in which ongoing DNA synthesis is not inhibited.They are also defective in the activation of the S and G2 phase checkpoint.DDR proteins ATM,Chk2,MDC1,NBS1 and gammaH2AX also fail to form discrete foci.These results demonstrate that failure of DDR may play an active role in chemoresistance to TMZ.DNA damages by TMZ are repaired by MMR proteins in a futile,reiterative process,which activates DDR signaling network that ultimately leads to the onset of cell death.GBM cells may survive genetic insults in the absence of DDR.We anticipate that our findings will lead to more studies that seek to further define the role of DDR in ultimately determining the fate of a tumor cell in response to TMZ and other DNA methylators.