神经胶质瘤中PTEN、Ki-67和HIF-1α的表达及临床意义

目的:抑癌基因PTEN、癌基因Ki-67及HIF-1α对多种人类肿瘤的恶性进展均起重要的调控作用。本研究主要探讨PTEN、Ki-67及HIF-1α在人脑胶质瘤中的表达及临床意义,为胶质瘤患者预后的判定、分子病理学的诊断、基因靶向的治疗奠定理论基础。方法:在83例原发性人脑胶质瘤组织样本中,通过免疫组化的方法检测PTEN、Ki-67及HIF-1α的表达情况,并分析其表达相互间及其表达与肿瘤恶性级别之间的相关性。结果:在正常脑组织中,PTEN的表达均为阳性,Ki-67的表达均为阴性,10%(1/10)的样本HIF-1α的表达为阳性。在胶质细胞瘤中,PTEN的表达显著降低(P=0.001),而Ki-67(P0.001)和HIF-1α(P=0.001)的表达明显增高。随肿瘤恶性级别的增高,PTEN的表达呈降低趋势(P0.001),而Ki-67和HIF-1α的表达呈升高趋势(两者P均0.001)。相关性分析表明,PTEN的表达与Ki-67和HIF-1α的表达呈负相关(r值分别为-0.289和-0.304;P值分别为0.008和0.005),Ki-67的表达与HIF-1α的表达呈正相关(r=0.833;P0.001)。结论:胶质瘤组织缺乏抑癌基因PTEN蛋白的表达,而高度表达癌基因Ki-67和HIF-1α。抑癌基因PTEN表达减少或失活,癌基因Ki-67和HIF-1α的过表达对胶质瘤恶性进展可能起到至关重要的作用。PTEN、Ki-67和HIF-1α蛋白的联合检测对胶质瘤恶性程度和预后的判定有十分重要的临床意义。     

HCMV IE86对恶性胶质瘤细胞凋亡及p53表达活性的影响

人巨细胞病毒(human cytomegalovirus,HCMV)能诱导肿瘤细胞恶性转化且抑制肿瘤细胞凋亡,但HCMV编码的主要即刻早期调控蛋白IE86在这一过程中是否发挥关键作用仍然未知。为探究IE86对基因修饰荷胶质瘤小鼠p53表达水平及恶性胶质瘤细胞凋亡情况的影响,本研究通过PCR技术鉴定基因修饰小鼠IE86表达情况;实时定量PCR技术检测IE86和p53mRNA表达水平变化;免疫组织化学方法检测p53和p21蛋白的表达水平;TUNEL检测肿瘤组织细胞凋亡情况。结果显示,成功构建了IE86基因修饰小鼠模型;与IE86阴性组相比IE86阳性组p53表达水平上升(P0.05),但p21表达水平下降(P0.05);IE86阳性组细胞抗凋亡能力增强(P0.05)。以上结果表明,在基因修饰的小鼠中IE86持续表达但p53转录活性的指示标志p21下调,且IE86可提高恶性胶质瘤细胞抗凋亡能力。     

人脑胶质瘤CDK4、CyclinD1和P16基因蛋白表达的免疫组织化学研究

采用检测人脑胶质瘤中CDK4、CyclinD1和P16基因蛋白的表达情况,探讨G1→S期细胞周期调节蛋白在胶质瘤发生,发展过程中的作用。对39例近期手术的胶质瘤标本和8例瘤旁正常脑组织标本进行免疫组织化学检测。结果显示：CDK4蛋白在良性、交界性胶质瘤和瘤旁正常脑组织中的表达差异没有显性意义（P＞0.05）,在恶性胶质瘤中的表达却有明显地增高,与前两比较差异均有显性意义（P＜0.05）。P16蛋白在恶性胶质瘤中的表达显低于在瘤旁正常脑组织和良性、交界性胶质瘤中的表达（P＜0.01）,但在后两中的表达差异没有显性意义（P＞0.05）。CyclinD1蛋白在三中的表达水平均较低且差异无显性意义（P＞0.05）。结果表明：CDK4蛋白的表达增高和P16蛋白的表达下调发生在胶质瘤的较晚期阶段,与胶质瘤的恶性变和恶性胶质瘤的发生有关,而CyclinD1蛋白的表达可能与胶质瘤的发生和发展无关。     

神经胶质瘤细胞ATF5表达水平对HCMV复制的影响

人巨细胞病毒(human cytomegalovirus,HCMV)在神经胶质瘤细胞中的复制水平不一,其机制尚不清楚。本研究通过下调转录激活因子5(ATF5)在神经胶质瘤细胞中的表达,检测HCMV感染神经胶质瘤细胞后病毒复制水平的变化。首先用HCMV AD169(MOI=5)分别感染U87、SY5Y及A172细胞,观察细胞形态变化,分别在24、48、72、96、120 h取各时间点上清液检测病毒滴度;Real-time PCR检测HCMV即刻早期基因(IE2)、早期基因(UL44)、晚期基因(UL99)及ATF5的表达情况;Western-blot检测病毒基因编码蛋白及ATF5表达的情况。结果显示HCMV在U87、SY5Y细胞中复制水平与病毒在A172细胞中复制水平相比,U87、SY5Y细胞组明显高于A172细胞组(P0.05),ATF5表达在U87、SY5Y细胞组与A172细胞组相比,U87、SY5Y细胞组ATF5表达明显高于A172组(P0.05);利用慢病毒介导的RNA干扰技术下调ATF5在U87、SY5Y细胞的表达,用HCMV感染细胞检测病毒基因及蛋白的表达,结果ATF5表达下调可抑制HCMV的复制(P0.05)。以上结果表明,在胶质瘤细胞中下调ATF5表达水平可以抑制HCMV的复制水平。     

人脑胶质瘤中热休克蛋白70、Caspase-3 的表达及临床意义

目的:探讨热休克蛋白70、caspase-3在人脑胶质瘤中的表达和临床意义。方法:收集2008年7月～2010年12月汕头大学医学院第二附属医院神经外科手术获取的人脑胶质瘤组织标本35例,另选择20例脑外伤手术中切除的正常脑组织标本作为对照组。采用EnVision免疫组化方法检测脑胶质瘤组织和正常脑组织中热休克蛋白70、caspase-3的表达,并分析其与脑胶质瘤组织临床病理特征之间的关系。结果:HSP70在胶质瘤组和对照组中的阳性表达率分别为74.3%和25.0%,胶质瘤组的HSP70表达明显高于对照组(P<0.05)。caspage-3在胶质瘤组和对照组中的阳性表达率分别为34.3%和80.0%,胶质瘤组的caspage-3阳性表达率均明显低于对照组(P<0.01)。HSP70和caspase-3的阳性表达与胶质瘤的病理学分级、术后复发情况密切相关(P<0.05)。相关分析表明,胶质瘤组织中HSP70阳性表达率和caspase-3表达呈负相关(r=-0.568,P<0.05)。结论:胶质瘤组织中HSP70呈高表达,而caspase-3表达下调,两者均在胶质瘤浸润、复发等恶性演进过程中发挥重要作用;HSP70可能通过某些途径抑制caspase-3表达来抑制胶质瘤恶性细胞的凋亡发生。     

层粘连蛋白及基质金属蛋白酶-2在人脑胶质瘤侵袭过程中的相关研究

目的研究层粘连蛋白(Laminin, LN)及基质金属蛋白酶-2(Matrix metalloproteinases-2,MMP-2)在人脑胶质瘤侵袭中的相互关系,探索人脑胶质瘤侵袭转移的机制.方法用免疫组织化学SP法检测LN和MMP-2在27例人脑胶质瘤、6例颅内转移瘤及5例正常脑组织的表达情况.结果 1)LN在高度恶性的胶质瘤中的表达显著高于颅内转移瘤及其它各组(9.584±6.448,P<0.05), MMP-2的表达随着胶质瘤恶性程度的增高而增加(P<0.05),其在颅内转移瘤中的表达与高度恶性组无显著差异性(P>0.05);2)MMP-2/LN比值在颅内转移瘤中显著高于其它各组(0.120±0.069, P<0.05),其它各组间无统计学差异,该值相对恒定;3)LN与MMP-2在上述组织中的表达呈正相关( r＝0.605,P=0.0002<0.01).结论在人脑胶质瘤中,MMP-2表达增加使得胶质瘤细胞呈现颅内浸润,而LN的表达随MMP-2表达的增加而增加却阻遏了胶质瘤细胞向颅外转移,两者的相互作用使得胶质瘤既表现出颅内广泛的侵袭性,又不转移到颅外.     

HCMV感染对恶性胶质瘤U87细胞增殖及ATF5表达的影响

人巨细胞病毒(HCMV)能够诱导肿瘤细胞的恶性转化,但其分子机制尚有待进一步探索。探讨HCMV是否通过调控转录激活因子5(ATF5)的表达变化促进胶质瘤细胞的增殖。采用HCMV AD169株(MOI=5)感染神经胶质瘤U87细胞株,MTT方法观察HCMV感染0、12、24、48 h后细胞的增殖活性。Real-time PCR及Western-blot检测HCMV感染U87细胞后ATF5基因及蛋白的表达水平变化。以慢病毒为载体的靶向ATF5小干扰RNA构建载体,敲低ATF5表达水平后感染HCMV,MTT检测病毒感染细胞的增殖活性变化。HCMV感染神经胶质瘤U87细胞后,与未感染组比较,增值活性明显升高(P0.05),ATF5表达水平上升,表明HCMV感染使胶质瘤细胞增殖活性提高,细胞抗凋亡能力增强。成功构建沉默ATF5细胞系siATF5 U87,HCMV感染siATF5 U87细胞后使细胞增殖活性减弱,抗凋亡能力下降。以上实验结果表明,HCMV感染上调胶质瘤U87细胞ATF5的表达水平,促进细胞的增殖。因此HCMV感染可能通过调控ATF5信号通路增加细胞恶性性状,为治疗胶质瘤提供一个新的思路。     

黄芩素抑制人巨细胞病毒感染星形胶质细胞的实验研究

目前对人巨细胞病毒(human cytomegalovirous,HCMV)感染尚无特异有效的治疗和预防手段,研究通过观察黄芩素(baicalein,BAI)抑制HCMV体外感染人星形胶质细胞引起的IE、pp65 mRNA及蛋白表达的变化,探讨黄芩素抗HCMV感染的机制。运用MTT法检测BAI组、HCMV组、HCMV+BAI组和对照组细胞的细胞活性,观察BAI对HCMV感染致人星形胶质细胞增殖异常的抑制作用;Real-time PCR检测不同组之间IE、pp65 mRNA表达的变化;免疫荧光、Western blot技术检测IE、pp65蛋白表达的变化。MTT结果显示,20μmol/L BAI+HCMV组的吸光值在24、48、72 h均高于HCMV组(P0.05);形态学观察病毒感染48 h时,HCMV组细胞出现明显的细胞病变效应(CPE),而20μmol/L BAI+HCMV组细胞状态较好,CPE不明显;Real-time PCR结果显示在感染48和72 h时20μmol/L BAI+HCMV组IE、pp65的mRNA表达明显低于HCMV组(P0.05);免疫荧光、Western blot结果显示20μmol/L BAI+HCMV组细胞的IE、pp65蛋白表达明显低于HCMV组(P0.05)。以上结果显示,适当浓度的黄芩素能抑制HCMV感染所致的细胞增殖异常,同时降低IE及pp65的mRNA和蛋白表达量。     

HSP70和JNK信号转导通路在肝癌组织中的表达及意义

目的探讨HSP70和JNK信号转导通路在肝癌组织中的作用,以及它们之间的关系。方法用SP免疫组化方法检测62例肝癌组织中HSP70、JNK1、JNK2和c-Jun的表达。应用SSPS统计软件进行数据处理。结果(1)HSP70蛋白1级染色16例(25.8%),2级染色25例(40.3%),3级染色21例(33.9%)。JNK1、JNK2和c-Jun蛋白低表达分别为40例(64.5%)、33例(53.2%)和36例(58.1%),高表达分别为22例(35.5%)、29例(46.8%)和26例(41.9%)。(2)HSP70蛋白表达与肝癌分化程度呈正相关(r=0.449,P=0.000),JNK1、JNK2和c-Jun蛋白表达均与肝癌分化程度呈负相关(r=-0.351,P=0.005;r=-0.303,P=0.017;r=-0.302,P=0.017)。(3)HSP70蛋白的表达与JNK1(r=-0.385,P=0.002)、JNK2(r=-0.309,P=0.015)和c-Jun(r=-0.302,P=0.017)蛋白的表达呈负相关。(4)Kaplan-Meier法生存分析发现HSP70和JNK1蛋白的表达与术后无复发生存时间密切相关(P<0.01)。(5)多因素Cox比例风险模型分析,结果HSP70与预后明显相关(P=0.004)。结论HSP70蛋白与肝癌的进展和预后密切相关。JNK信号转导通路与肝癌的分化有关。HSP70可能通过抑制JNK信号传导途径,而阻断由其介导的肝癌细胞的凋亡,提高了肝癌细胞在应激状态下的稳定性。     

Transcriptional activation of endoplasmic reticulum chaperone GRP78 by HCMV IE1-72 protein

Glucose-regulated protein 78 (GRP78), a key regulator of endoplasmic reticulum (ER) stress, facilitates cancer cell growth and viral replication. The mechanism leading to grp78 gene activation during viral infection is largely unknown. In this study, we show that the immediate-early 1 (IE1-72) protein of the human cytomegalovirus (HCMV) is essential for HCMV-mediated GRP78 activation. IE1-72 upregulated grp78 gene expression depending on the ATP-binding site, the zinc-finger domain and the putative leucine-zipper motif of IE1-72, as well as the ER stress response elements (ERSEs) on the grp78 promoter. The purified IE1-72 protein bound to the CCAAT box within ERSE in vitro, whereas deletion mutants of IE1-72 deficient in grp78 promoter stimulation failed to do so. Moreover, IE1-72 binding to the grp78 promoter in infected cells accompanied the recruitment of TATA box-binding protein-associated factor 1 (TAF1), a histone acetyltransferase, and the increased level of acetylated histone H4, an indicator of active-state chromatin. These results provide evidence that HCMV IE1-72 activates grp78 gene expression through direct promoter binding and modulation of the local chromatin structure, indicating an active viral mechanism of cellular chaperone induction for viral growth.     

Oncogenic reg IV is a novel prognostic marker for glioma patient survival

ABSTRACT: Aim The aberrant expression of regenerating islet-derived family member, 4 (Reg IV) has been found in various human cancers. However, the roles of Reg IV gene and its encoding product in human glioma have not been clearly understood. Therefore, the aim of this study was to investigate the clinicopathological significance of Reg IV expression in glioma. METHODS: Reg IV mRNA and protein expression in human gliomas and non-neoplastic brain tissues were respectively detected by real-time quantitative RT-PCR assay, Western blot, and immunohistochemistry. The association of Reg IV immunostaining with clinicopathological factors and prognosis of glioma patients was also statistically analyzed. RESULTS: Reg IV mRNA and protein expression levels in glioma tissues were both significantly higher than those in the corresponding non-neoplastic brain tissues (both P?相似文献   

脑胶质瘤组织中p16基因启动子区CpG岛甲基化检测及其临床意义研究

目的：研究脑胶质瘤中p16基因启动子区甲基化情况及其临床意义。方法：用甲基化特异性PCR技术检测42例脑胶质瘤组织和癌旁正常脑组织中p16基因启动子甲基化,并分析该基因启动子甲基化与临床病理特征之间的关系。结果：脑胶质瘤组织中p16基因异常甲基化率（38.27%）显著高于癌旁正常脑组织中p16基因的异常甲基化率（8.8%,P=0.000）。发生甲基化的肿瘤组织或者正常脑组织中p16基因mRNA和蛋白表达显著降低。此外,p16基因异常甲基化和肿瘤病理分级有相关性（P=0.007）,而与患者性别、年龄及肿瘤类型等临床特征无关（P=0.669,0.869和0.944）。结论：p16基因启动子区CpG岛高甲基化与p16表达下调相关,推测p16启动子区CpG岛高甲基化是导致p16基因在脑胶质瘤中表达下调的重要因素,有望成为脑胶质瘤早期辅助诊断的分子标志物之一。     

Decreased expression of microRNA-200b is an independent unfavorable prognostic factor for glioma patients

Background and aimAs a member of the microRNA (miR)-200 family, miR-200b has been recognized as one of the fundamental regulators of epithelial–mesenchymal transition, chemosensitivity, cell proliferation, and cell cycle. Especially in glioma, miR-200b targets the CREB1 gene and suppresses the tumor cell growth in vitro. However, its involvement in human glioma has not yet been determined. The aim of this study was to investigate the clinical significance of miR-200b expression in this disease.MethodsmiR-200b expression in 266 pairs of human gliomas and matched nonneoplastic brain tissues was measured by real-time quantitative RT-PCR assay.ResultsCompared with nonneoplastic brain tissues, the expression level of miR-200b was significantly decreased in glioma tissues (tumor vs. normal: 2.87 ± 2.05 vs. 8.78 ± 2.50, P < 0.001). Of 266 patients with gliomas, 166 (62.41%) were in low miR-200b expression group. In addition, we found that the glioma tissues from high-grade tumors (grade III and IV) had much lower miR-200b expression than glioma tissues from low grade tumors (grade I and II). Moreover, the expression level of miR-200b was positively correlated with Karnofsky performance status (KPS) scores of glioma tissues. The results of a 60-month follow-up in 266 glioma patients further demonstrated that lower miR-200b expression was correlated with worse progression-free survival and overall survival in the patients with grade III and IV gliomas. Both univariate and multivariate analyses revealed that miR-200b was an independent prognostic indicator for glioma.ConclusionThese findings prove that the decreased expression of miR-200b may be associated with malignant tumor progression and poor prognosis in patients with gliomas, suggesting the potential role of miR-200b in glioma management. miR-200b may be a novel and valuable signature for predicting the clinical outcome of patients with gliomas.     

Role of human cytomegalovirus immediate-early proteins in cell growth control

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus that has been implicated in several disorders, including an association between HCMV reactivation and the overproliferation of arterial smooth muscle cells observed in restenosis. Although HCMV can mediate a growth-arrest phenotype in infected cells, the virus can also promote an environment conducive to proliferation. Here, we present evidence that the HCMV immediate-early (IE) proteins, IE1-72 and IE2-86, may be responsible for inducing this proliferative environment by altering cell cycle control. We find that expression of either of these IE proteins can alter the cell cycle distribution of randomly cycling cells towards S and G(2)/M phases. Additionally, we find that expression of IE2-86, but not IE1-72, induces quiescent cells into S phase and delays cell cycle exit. In the absence of p53, IE1-72 expression can induce S phase and delay cell cycle exit. We also demonstrate that p53 protein levels increase in fibroblasts following the expression of IE1-72. The observed accumulation of p53 protein in IE1-72-expressing cells may account for the inability of IE1-72 to induce S phase and delay cell cycle exit. Our data suggest that expression of HCMV IE1-72 and IE2-86 is sufficient to alter the cell cycle to generate an environment conducive to proliferation.