脑胶质瘤P53基因及其表达蛋白研究进展

P53肿瘤抑制基因的缺失、点突变是迄今发现的胶质瘤最常见的分子生物学改变。近来的研究表明,星形细胞瘤P53基因突变率较其它类型的胶质瘤高,胶质瘤P53基因突变多分布于第4—8外显子上,以错义突变为主,常常合并另一等位基因杂合性丢失。P53基因的缺失、突变和胶质瘤的病理级别、增殖能力有关。免疫组化研究显示,恶性胶质瘤常常存在P53蛋白过度表达。本文就此方面的进展及面临的问题作一概述。     

P16与P53蛋白在脑胶质瘤中的表达及意义

目的:探讨P16与P53蛋白在人脑胶质瘤中的表达及与病理分级的关系。方法:采用免疫组化方法检测52例胶质瘤手术标本及2株人脑胶质瘤细胞系中P16与P53蛋白的表达状况,并分析其与该类肿瘤病理级别的关系。结果:随胶质瘤病理级别的升高P16蛋白的表达率逐渐降低,Ⅰ～Ⅳ级阳性率分别为75.0％、64.7％、42.8％和33.3％,低度恶性组(Ⅰ～Ⅱ级)与高度恶性组(Ⅲ～Ⅳ级)间有显著差异(P<0.05)。P53蛋白表达率随胶质瘤病理级别的升高有上升趋势。结论:P16及P53基因表达在胶质瘤恶性演变中有重要意义。     

达纳康抑制大鼠局灶性脑缺血再灌注损伤后P^53蛋白表达及细胞凋亡的研究

目的研究达纳康在大鼠局灶性脑缺血再灌注损伤中的脑保护作用及其分子机制.方法采用线栓法建立大鼠大脑中动脉(MCAO)缺血1h再灌注24h模型,18只雄性大鼠随机分为假手术组、生理盐水对照组和达纳康治疗组,每组6只.采用Zea-Longa评分法观察神经功能缺损程度,采用免疫组织化学方法、TUNEL法分别观察各组P53蛋白表达和细胞凋亡.结果假手术组神经功能缺失评分为0分,高倍视野下无P53蛋白染色阳性细胞及凋亡细胞;达纳康治疗组神经功能缺失评分(0.48±0.37分)、P53蛋白染色阳性细胞数(5.16±1.84个/高倍视野)、凋亡细胞数(4.18±1.21个/高倍视野)均较生理盐水对照组(2.76±0.82分、10.43±1.56个/高倍视野、8.16±1.50个/高倍视野)显著减少(P<0.01).结论达纳康可明显减轻局灶性脑缺血再灌注损伤,其抑制神经细胞P53蛋白的表达,进而抑制细胞凋亡,是其脑保护作用的分子机制之一.     

人脑胶质瘤组织中P53基因的突变研究

人脑胶质瘤组织中Ｐ５３基因的突变研究高振强高志萍为了研究Ｐ５３基因在脑肿瘤发生过程中的作用，我们采用目前检测基因突变最先进ＰＣＲ－ＳＳＣＰ技术，对脑胶质瘤组织中Ｐ５３基因进行了研究。一、材料与方法脑胶质瘤来自医院手术标本，共３０例，其中多形性成胶质细...     

大鼠全脑缺血再灌注后额叶神经细胞凋亡与P^53蛋白表达的实验

目的 探讨大鼠全脑缺血再灌注后不同时间对额叶神经细胞凋亡及P^53蛋白表达的影响。方法 采用改良的Pulsineli 4-血管阻断(4-VO)方法建立SD大鼠急性全脑缺血模型，随机分为3组：正常组（n=7)；假手术组（n=49)；手术组（n=49)。缺血15min，分别于再灌注1、6、12、24、48、72h和7d断头取脑，采用TUNEL方法检测神经细胞凋亡，SP免疫组化方法观察额叶P^53蛋白的表达。结果 全脑缺血再灌注24h，可见少量TUNEL阳性细胞，再灌注48h可见较多TUNEL阳性细胞，72h出现大量TUNEL阳性细胞，7d明显减少。免疫组化染色：缺血组于再灌注24h可见少量P^53蛋白表达，48h达高峰，72h有所下降，7d明显下降，这种表达主要在细胞核内。结论 急性全脑缺血再灌注后的迟发性神经元坏死是以凋亡的方式发生的，全脑缺血再灌注后，额叶P^53蛋白表达增加，神经细胞凋亡和P^53蛋白的表达在一定时间内呈正相关。     

慢性低O2高CO2大鼠脑神经细胞凋亡及P53蛋白表达研究

神经元死亡分两种形式 :一种为细胞能量代谢障碍 ,导致细胞水肿及坏死 ;另一种为迟发性神经元死亡 ,表现细胞凋亡。临床上慢性阻塞性肺病 (chronic obstructivepulmonary disease,COPD)常有缺氧 (O2 )和二氧化碳(CO2 )潴留诱发脑病 ,而慢性低 O2 高 CO2 大鼠神经细胞凋亡及 P53蛋白表达尚未见报道。本实验采用先期建立的慢性低 O2 高 CO2 大鼠模型 ,通过电镜、原位末端标记、免疫组织化学、流式细胞仪技术观察脑神经细胞凋亡现象 ,为认识和治疗慢性缺 O2 脑损伤提供理论依据。1　材料和方法1 .1　动物模型的制备 :雄性 SD大鼠 (温州…     

p53,CerbB—2和PCNA在脑胶质瘤中表达的意义及其 …

目的 研究７６例脑质瘤的ｐ５３ＣｅｒｂＢ－２和ＰＣＮＡ表达意义及其相关性。方法 应用ＳＰ微波免疫组化技术和统计学分析。结果 （１）在７６例脑胶质瘤组织中；ｐ５３，ＣｅｒｂＢ－２和ＰＣＮＡ的阳性表达率分别是４４．７４％（３４／７６），３４．２１％（２６／７６）和８０．２６％（６１／７６）。（２）ｐ５３的表达强度与胶质瘤的组织学类型和恶性程度呈显著正相关（Ｐ〈０．０１）。（３）ｐ５３ＣｅｒｂＢ－２和Ｐ     

脑胶质瘤P73蛋白表达研究

目的:了解P73基因是否参与脑胶质瘤的病理发生。方法:利用免疫组化方法检测了63例不同级别的脑胶质瘤P73和P53蛋白表达情况。结果:17例脑胶质瘤呈P73蛋白阳性表达,且其表达阳性率在脑胶质瘤中病理分级高的明显高于病理分级低的(x~2=4.75,P<0.05)。17例P73蛋白表达阳性的脑胶质瘤中,12例呈P53过度表达。结论:野生型P73蛋白过度表达可能参与脑胶质瘤的发生、发展。     

儿童恶性脑胶质瘤P53与细胞增殖核抗原表达的预后价值

目的探讨Ｐ５３与细胞增殖核抗原（ＰＣＮＡ）在儿童恶性脑胶质瘤表达的预后价值。方法采用ＡＢＣ免疫组化方法对３３例儿童恶性脑胶质瘤Ｐ５３与ＰＣＮＡ表达进行回顾性研究。结果３３例儿童恶性脑胶质瘤中Ｐ５３表达阳性１５例（４５％），ＰＣＮＡ表达阳性２９例（８８％）。间变性星形细胞瘤、胶质母细胞瘤及髓母细胞瘤Ｐ５３蛋白表达的阳性比例分别为５／１２、９／１６、１／５，肿瘤Ｐ５３蛋白阴性者其细胞增殖活性均较阴性者高（Ｐ＜００５）；ＰＣＮＡ标记指数与肿瘤的恶性程度呈正相关（Ｐｅａｒｓｏｎ列联系数＝０．５６，Ｐ＜００１）。Ｐ５３或ＰＣＮＡ表达阳性者存活率分别显著低于Ｐ５３或ＰＣＮＡ表达阴性者（Ｐ＜００５，Ｐ＜００１）。结论Ｐ５３基因突变以及由此导致的细胞异常增殖与儿童恶性脑胶质瘤的发生和发展有关；ＰＣＮＡ能较好地反映胶质瘤的恶性程度，其表达检测对临床预后判定有重要参考价值。     

Epidermal growth factor receptor and p53 protein expression in human glioblastomas

p53 mutations and amplification of epidermal growth factor receptor (EGFR) gene are the most frequently detected genetic alterations in glioblastomas; thus, these changes seem to delineate two subgroups of glioblastomas: those originated de novo and those originated from preexistent low grade astrocytomas. Paraffin-embedded surgical specimens of 30 human glioblastomas were analyzed immunohistochemically for the presence of p53 protein and EGFR. Approximately half of the cases were p53 protein-positive while one-third were EGFR positive. Only three cases were positive for both p53 protein and EGFR. There was no difference between the average ages of patients with only-p53-positive, and double-negative tumors, while three glioblastomas with both p53 protein and EGFR immunopositivity occured in older patients (mean age 67.0 years, p < 0.02). Patients with only-EGFR-positive tumors were younger, but not significantly (44.3 years, p < 0.1). This study supports the notion that there are two main subpopulations of glioblastoma—with EGFR and with p53 protein overexpression.     

Distribution of p53 protein expression in gliosarcomas: an immunohistochemical study

Summary The wild-type p53 gene product is a nuclear phosphoprotein that suppresses cell and tumor growth. Mutations of the p53 gene are by now the most frequently recognized genetic alterations in human malignancies and occur in many types of carcinomas as well as in astrocytomas and sarcomas. Wild-type p53 protein has a short half-life, is present in very low quantities in normal cells and cannot be detected immunohistochemically. Mutant p53 proteins have longer half-lives and are usually present in immunohistologically detectable amounts. It is generally agreed that the presence of p53 immunostaining indicates the presence of an abnormal p53 protein and is strongly suggestive of a mutation in the p53 gene. In this study, we stained paraffin sections from eight samples of gliosarcomas from seven patients with an antibody to p53. All tumors contained p53-immunoreactive nuclei in both the glial and the sarcomatous component. In five tumors, a majority of nuclei was positive in the sarcomatous component while only a minority of nuclei was positive in the glial areas. In one tumor, the reverse was seen. In another tumor, approximately half the nuclei were positive in both components and in one tumor, only a minority of nuclei were positive in either component (this lesion was the recurrence of a tumor in which the majority of the sarcoma's nuclei had been positive). These data indicate that p53 mutations may play a role in the pathogenesis of gliosarcomas and suggest an origin of both the glial and sarcomatous components from a common progenitor.Supported by a grant from the Physicians Referral Service of the University of Texas M.D. Anderson Cancer Center. This work was presented in abstract form at the meeting of the American Association of Neuropathologists in St. Louis, June 18–21, 1992     

p53 protein expression in central nervous system tumors: an immunohistochemical study with CM1 polyvalent and DO-7 monoclonal antibodies

Summary Formalin-fixed, paraffin-embedded surgical specimens from 137 primary central nervous system tumors, including 26 astrocytomas (21 fibrillary, 1 protoplasmic, 1 gemistocytic and 3 pilocytic), 26 anaplastic astrocytomas, 9 glioblastomas, 1 gliosarcoma, 8 oligodendrogliomas, 4 ependymomas, 1 anaplastic ependymoma, 2 subependymomas, 3 paragangliomas, and 57 meningiomas, were immunostained with the CM1 polyclonal (pAb) and the DO-7 monoclonal (mAb) antibodies against the p53 protein, using the streptavidin/peroxidase method. In addition, two series of 17 and 9 medulloblastomas were also immunostained with the above pAb and mAb, respectively. p53 protein expression was observed in 7 fibrillary astrocytomas, 17 anaplastic astrocytomas, 5 glioblastomas, 1 gliosarcoma, 1 oligodendroglioma, 1 anaplastic ependymoma, and 4 meningiomas with the CM1 pAb. An additional 10 cases (i.e., 3 anaplastic astrocytomas and 7 meningiomas) were found to be p53 protein positive with the DO-7 mAb. Of the medulloblastomas, 8 (of the 17) and 4 (of the 9) were found to express p53 protein with CM1 pAb and DO-7 mAb, respectively. Our results indicate that p53 protein is expressed in a number of central nervous system neoplasms, and suggest that in astrocytic tumors a possible association may exist between p53 protein expression and tumor progression through increasing histological grades of malignancy.     

大鼠全脑缺血再灌注后额叶神经细胞凋亡与P53蛋白表达的实验研究

目的 探讨大鼠全脑缺血再灌注后不同时间对额叶神经细胞凋亡及P~(53)蛋白表达的影响。方法采用改良的Pulsineli 4-血管阻断(4-VO)方法建立SD大鼠急性全脑缺血模型,随机分为3组:正常组(n=7);假手术组(n=49);手术组(n=49)。缺血15min,分别于再灌注1、6、12、24、48、72h和7d断头取脑,采用TUNEL方法检测神经细胞凋亡,SP免疫组化方法观察额叶P~(53)蛋白的表达。结果 全脑缺血再灌注24h,可见少量TUNEL阳性细胞,再灌注48h可见较多TUNEL阳性细胞,72h出现大量TUNEL阳性细胞,7d明显减少。免疫组化染色:缺血组于再灌注24h可见少量P~(53)蛋白表达,48h达高峰,72h有所下降,7d明显下降,这种表达主要在细胞核内。结论 急性全脑缺血再灌注后的迟发性神经元坏死是以凋亡的方式发生的,全脑缺血再灌注后,额叶P~(53)蛋白表达增加,神经细胞凋亡和P~(53)蛋白的表达在一定时间内呈正相关。     

大鼠局灶性脑缺血后CPP32和P53蛋白的表达

目的　探讨大鼠脑缺血后神经元损害过程中CPP32和P5 3蛋白表达的变化。方法　建立大鼠大脑中动脉闭塞 (MCAO 2h)模型 ,采用免疫组化方法观察CPP32和P5 3蛋白在大鼠脑缺血后不同时间的动态变化。结果　CPP32蛋白在脑缺血再灌注 2 2h和 4 6h ,阳性表达最明显。而P5 3在脑缺血再灌注 2 2h阳性表达最明显 ,并持续至再灌注 70h。阳性表达主要位于神经元严重受损的缺血区内。结论　CPP32和P5 3蛋白表达与脑缺血后神经细胞死亡关系密切。     

p53基因联合顺铂对实验性胶质瘤的治疗作用

目的观察p53基因和顺铂对实验性胶质瘤的治疗作用。方法先以人胶质瘤细胞株U251建立裸鼠胶质瘤模型,然后瘤体内注射p53基因和/或腹腔内注射顺铂,定期测量肿瘤的大小。结果观察30d,p53基因联合顺铂治疗组的肿瘤大小为(0.44±0.05)cm3,顺铂治疗组为(0.92±0.03)cm3,p53基因治疗组为(1.16±0.10)cm3,对照组为(1.72±0.17)cm3,各组间差异有显著性意义(P<0.05)。结论对实验性胶质瘤,p53基因联合顺铂治疗组的疗效好于单用p53基因或顺铂治疗组。     

Decreased expression of NDRG2 is related to poor overall survival in patients with glioma

Members of the NDRG (N-Myc downstream-regulated) gene family have been shown to play a variety of roles in human malignancies. In the present study, we examined the expression of NDRG2 protein in glioma samples of WHO grades I–IV. We also investigated the association between NDRG2 expression and survival. Immunohistochemical analysis was used to measure NDRG2 protein expression in 316 specimens of human glioma and 41 normal control tissues. Survival analysis was performed using the Kaplan–Meier method and Cox’s proportional hazards model. We found that NDRG2 expression was reduced in glioma relative to normal tissue, and that NDRG2 expression decreased with increasing glioma grade. Kaplan–Meier analysis showed that patients without NDRG2 expression had a lower survival rate than other patients. Multivariate analysis showed that NDRG2 expression was an independent prognostic factor for overall survival of patients with glioma. The present study provides the first evidence that NDRG2 expression is decreased in gliomas, indicating that NDRG2 may play an inhibitory role during the development of gliomas. NDRG2 expression may also be a significant and independent prognostic indicator for glioma.     

Humoral immune response to p53 in malignant glioma

p53 immunoreactivity and humoral immune response to p53 were examined in 14 patients with malignant glioma, including 4 patients with leptomeningeal glioma cell dissemination. Twelve patients expressed p53 protein within the tumour tissue. p53 antibodies were detected in the serum in 2 of 14 patients but never in the cerebrospinal fluid (CSF). Soluble p53 protein was detected neither in serum nor in CSF of the glioma patients. CSF levels of the immunosuppressive cytokine, transforming growth factor (TGF)-β, were elevated in the glioma patients, including those with a humoral response to p53. These preliminary findings raise the possibility of systemic humoral immune responses to antigens, including mutant p53, expressed by glioma cells in the central nervous system. Received: 7 August 1997 Received in revised form: 29 October 1997 Accepted: 20 November 1997     

Expression of retinoblastoma gene product and p21 (WAF1/Cip 1) protein in gliomas: correlations with proliferation markers, p53 expression and survival

Using immunohistochemistry we evaluated the expression of two negative regulators of the cell cycle, the retinoblastoma gene product (pRb) and the WAF1/Cip1 gene product (p21), in consecutive paraffin sections from 54 gliomas (49 astrocytomas and 5 oligodendrogliomas) and related it to clinicopathological parameters, proliferative fraction, p53 expression and survival. Survival analysis was restricted to the group of diffuse astrocytomas (48 patients). pRb expression did not correlate with histological type, grade or p53 expression, while a moderately strong correlation existed between pRb expression and the percentages of proliferating cell nuclear antigen (PCNA) and MIB-1-positive cells. In 30% of cases we observed diminished pRb expression (i.e., a low pRb/Ki-67 ratio), irrespective of grade or histological type. p21 protein was elevated in 50% of cases, especially within the higher grades. The percentage of p21-positive cells was not related to histological type or grade but correlated loosely with PCNA and pRb expression. A p53-negative/p21-negative phenotype was characteristic of oligodendrogliomas and low-grade astrocytomas, whereas the p53-positive/p21-positive, p53-positive/p21-negative and p53-negative/p21-positive phenotypes were almost equally distributed among high-grade tumors. In survival analysis (either univariate or multivariate) diminished pRb expression was not a statistically significant prognostic indicator. In contrast, p21 expression emerged as an important indicator of shortened disease-free survival, in both univariate and multivariate analyses. Moreover, the double-positive p53/p21 phenotype tended to be associated with a shorter overall survival. Our results suggest that Rb gene deregulation does not significantly affect prognosis but p21 expression may play an important role in disease-free survival of astrocytoma patients. Received: 14 August 1997 / Revised: 6 November 1997 / Accepted: 28 November 1997