miR-7沉默表皮生长因子受体对胶质瘤细胞周期的影响

目的 研究miR-7阻遏脑胶质瘤细胞增殖周期由G1期向S期转化的内在机制.方法 脂质体转染miR-7表达质粒进入人脑胶质瘤细胞株U251,原位杂交和RT-PCR方法检测外源miR-7基因的整合效果;流式细胞术检测细胞周期变化,Western blot方法检测EGFR、CyclinD1、CyclinE、CDK2、CDK4、CDK6、P16、P21和P27的蛋白表达;SPSS13.0软件进行统计学分析.结果 RT-PCR结果显示miR-7基因被成功整合入U251胶质瘤细胞,原位杂交结果示miR-7主要定位于细胞核和细胞质;转染后瘤细胞增殖速度减慢,且大部分阻滞于G1期,处于分裂期S期的细胞比例明显减少(P＜0.05);miR-7转染组EGFR、CyclinD1、CyclinE、CDK2、CDK4和CDK6蛋白表达水平均有不同程度下降(P＜0.05),其中EGFR、CyclinD1、CDK4和CDK6的降低程度更为显著(P＜0.01),P16水平显著升高(P＜0.01),P21和P27的表达没有明显变化(P＞0.05).结论 miR-7可能通过有效沉默癌基因EGFR的表达途径,抑制细胞周期G1期调节蛋白复合体CyclinD1/CDK4/6的活性,并接受P16的协同作用,共同阻遏胶质瘤由G1期向S期转化,进而抑制肿瘤增殖;miR-7有望成为一种新的胶质瘤治疗候选药物.     

Rapid quantitative immunohistochemical assessment of human peripheral neuropathies using a monoclonal antibody against nerve growth factor receptor

Summary An analysis of nerve growth factor (NGF) receptor expression and density in human sural nerve biopsies was performed by immunocytochemistry with a murine monoclonal antibody against the human NGF receptor. Quantitative assessment of immunostaining density was made by histospectrophotometry on frozen sections. Although there was enhanced expression of NGF receptor within endoneurium in all patients with clinical neuropathies, expression was highest in nerves with axonal disease, consistent with the proposal that disruption of axon-Schwann cell interactions triggers the reexpression of the NGF receptor. These results with human nerves, together with previous studies with animal models, suggest that NGF and NGF receptor play important roles in the general response to neuronal injury.     

靶向表皮生长因子受体的shRNA抑制U251胶质瘤生长的实验研究

目的探讨靶向表皮生长因子受体(epidermal growth factor receptor,EGFR)的RNA干涉(RNAi)技术抑制恶性胶质瘤体外细胞系U251的EGFR表达后,在体内外对U251细胞生长抑制作用。方法在人EGFR开放阅读框的细胞内区酪氨酸激酶结构域选择1个siRNA靶序列、进行短发夹RNA(shRNA)表达载体psiRNA-2400的构建,并以含有随机序列的psiRNA-scr表达质粒为对照进行了脂质体介导的U251人脑恶性胶质瘤细胞系表达。应用RT-PCR检测EGFR表达水平,应用MTT法、流式细胞术和Matrigel基质生长实验评价肿瘤细胞转染前后的生物学行为。进一步应用裸鼠皮下荷瘤模型观察脂质体介导shRNA基因治疗对U251细胞生长抑制作用。对肿瘤组织应用免疫组化的方法进行EGFR、PCNA和GFAP表达比较。结果脂质体介导、靶向EGFR的shRNA可显著抑制U251细胞ECFR表达,MTT法分析显示psiRNA-2400转染组细胞生长抑制率为68%;与对照组和psiRNA-scr转染组比较,细胞周期分析结果表明psiRNA-2400转染组G_0～G_1期细胞数没有明显变化,进入S期的细胞数较对照组减少了12.7%～13%,而进入G_2期细胞则增加了10.5%～11.7%。Matrigel基质生长实验显示对照组和psiRNA-scr转染组细胞呈正常形态贴壁生长,而psiRNA-2400转染组细胞不能贴壁生长,呈团块状簇集生长。裸鼠皮下荷瘤模型实验显示psiRNA-2400显著抑制皮下肿瘤生长,组织病理学分析显示治疗组EGFR表达下降、PCNA标记指数降低而GFAP表达上调。结论靶向EGFR的RNAi技术可以显著抑制U251细胞的EGFR表达,在体内外对U251细胞生长均产生明显抑制作用。因此,shRNA表达质粒介导的基因治疗可以成为胶质瘤靶向性EGFR治疗的新策略。     

垂体生长激素腺瘤细胞表皮生长因子受体的表达

目的了解大鼠垂体生长激素腺瘤(GH3)细胞的表皮生长因子受体(EGFR)的表达情况.方法应用免疫组化的方法检测GH3细胞及阴性对照U-2OS细胞和阳性对照HO8910PM细胞的EGFR表达情况.结果 GH3细胞和HO8910PM细胞明显黄染,U-2OS细胞无明显染色;GH3、U-2OS和HO8910细胞表达EGFR的阳性细胞率分别为90.57%、4.84%和93.33%.结论垂体生长激素腺瘤细胞中存在着广泛的EGFR表达,而且具有较高的表达强度.     

脑膜瘤中EGFR和PTEN的表达及意义

目的探讨脑膜瘤组织中表皮生长因子受体（EGFR）和人10号染色体上缺失的磷酸酶和张力蛋白类似物（PTEN）表达的相互关系及意义。方法应用免疫组织化学SP法对60例脑膜瘤标本的EGFR和PTEN表达进行检测与分析。结果在90％（54／60）的脑膜瘤中EGFR过表达，非典型脑膜瘤及间变性脑膜瘤中EGFR的染色强度明显高于典型脑膜瘤（P〈0．05）；PTEN在各病理级别脑膜瘤中的阳性率为100％，而且各病理级别脑膜瘤中PTEN的染色强度无统计学差别（P〉0．05）。结论EGFR的表达强度与脑膜瘤的恶性程度有关，抑癌基因PTEN在脑膜瘤中未见缺失，可能与脑膜瘤的发生、发展无关。     

中国人胶质瘤中表皮生长因子受体基因的扩增及对患者预后的影响

目的：了解国人胶质瘤中表皮生长因子受体基因（EGFR）的扩增情况及对患者预后的影响。方法：使用半定量的Differential PCR方法对113例福尔马林固定-石蜡包埋（FFEP）胶质瘤标本内的EGFR基因扩增情况进行了检测；对其中的83例进行了生存分析研究。结果：113例胶质瘤中存在EGFR基因扩增的有26例，其中低度恶性组中仅占3.5％，而在高度恶性组中占42.1％。生存分析显示：EGFR基因扩增对患者预后并无显著影响，而起病年龄、肿瘤病理分级、肿瘤生长部位及起病症状为失语对患者术后生存期有显著影响。结论：恶性胶质瘤中存在着较为广泛的EGFR基因扩增，但EGFR基因的扩增与胶质瘤患者预后之间并不存在显著关联。     

抗人脑胶质瘤单克隆抗体的制备及识别抗原的提取

目的：制备新的抗人脑胶质瘤单克隆抗体（monoclonal antibody,McAb)，并提取其识别抗原。方法：以人脑恶性胶质瘤细胞系SHG－44为抗原免疫Balb/c小鼠，通过杂交瘤技术获得稳定分泌抗胶质瘤McAb的杂交瘤细胞株。以酶联免疫吸附测定及免疫组化等方法研究McAb的特性。通过亲和层析法提取该McAb识别的抗原。结果：得到1株稳定分泌抗体、效价高的杂交瘤细胞株，命名为SU－2000。鉴定表明该McAb属IgGl亚类，效价高，特异性高。识别的抗原位于胞膜，可能属于神经外胚层抗原；通过亲和层析法成功地提取出该抗原，十二脂硫酸3钠－聚丙烯酰胺凝胶电泳证实提取的抗原纯度高，分子量约为75kDa。结论：SU－2000 McAb及其识别抗原可进一步用于相关实验研究。     

Amplification and expression of the epidermal growth factor receptor gene during the progression of neuroepithelial tumours in vivo

Summary The epidermal growth factor receptor (EGFR) gene is homologous to the oncogene c-erbB. The occurrence of amplification and rearrangements at the EGFR gene locus is associated with malignancy in neuroepithelial tumours. Sixteen neuroepithelial tumours from eight patients with recurrence of their neoplasms were analysed for changes at the EGFR gene locus and for expression of EGFR. Ten tumours from five patients lacked changes at the EGFR gene locus. Three of eight individuals showed EGFR gene amplifications in both tumours with a higher grade of amplification in the second tumour. In addition to amplification, a rearrangement was found in both tumours of the first patient. In the second case an amplification of chromosome-7-specific c-met sequences was found in the regrown tumour, suggesting that a polysomy 7 was at least partly responsible for the higher copy number of the EGFR sequences. In both tumours of the third patient with EGFR gene amplification different alleles were amplified. In contrast to the findings at the DNA level the EGFR expression, analysed by immunohistochemical techniques, showed a more heterogeneous pattern after tumour progression.     

Destruction of sympathetic and sensory neurons in the developing rat by a monoclonal antibody against the nerve growth factor (NGF) receptor

The ability of the monoclonal antibody, 192-IgG, directed against the rat nerve growth factor (NGF) receptor to mimic or inhibit the actions of NGF was examined in vitro and in vivo. 192-IgG had no effect on morphology, survival, or protein synthesis rates of sympathetic neuronal cultures. When injected into newborn rats, destruction of sympathetic, but not sensory, neurons was produced. Injection prenatally produced more dramatic destruction of sympathetic neurons and, in addition, destruction of neural crest-derived sensory neurons. Therefore, although 192-IgG had no discernible effects in vitro, it produced a pattern of neuronal destruction in vivo qualitatively similar to that produced by antibodies to NGF itself.     

Induction of the morphologic changes of both acute and chronic experimental myasthenia by monoclonal antibody directed against acetylcholine receptor

Summary To investigate pathogenic mechanisms in experimental autoimmune myasthenia gravis (EAMG) and myasthenia gravis (MG), we studied the acute and chronic effects in rats of injection of rat monoclonal antibodies (MCABs) directed against the acetylcholine receptor (AChR). Animals were severely weak 12 h after a single injection, at which time macrophages were found invading endplate regions of muscle and cholinesterase-stained regions were separted from the underlying muscle fibers. Ultrastructural studies showed findings identical to the acute phase of EAMG: degenerating postsynaptic membranes and invasion and phagocytosis of endplate regions by macrophages. Animals receiving sublethal doses of MCAB recovered clinically by 4–5 days after injection. Recovery was accompanied by a progressive decrease in the number of macrophages associated with endplates and reapposition to the myofibers of the cholinesterasestained regions. Animals injected once, or repeatedly over several months, remained clinically and electromyographically normal after recovery from the initial episode of weakness, but their endplate ultrastructure was highly simplified with blunted or absent synaptic folds and shallow or absent secondary synaptic clefts. These studies demonstrate that anti-AChR MCABs can induce the changes of both acute and chronic EAMG. There is good correlation between the inflammatory changes and the acute clinical disease but poor correlation between morphological and clinical parameters in the chronic syndrome. The latter observation suggests that severe ultrastructural changes, similar to those seen in chronic EAMG and MG, cannot account, at least in rats, for the clinical and electrophysiologic abnormalities of MG.Supported in part by grants from the Muscular Dystrophy Association and the National Institutes of Health (NS15462, A19268)     

Immunological determinants of nerve growth factor involved in p140trk (Trk) receptor binding

Monoclonal anti-NGF antibodies that specifically inhibit the biological activity of mouse β-NGF were used to study the structural determinants involved in the interaction of NGF with its receptors gp75^LNGFR and Trk. None of the three antibodies–N60, M15, and 27/21–showed any reactivity toward denatured NGF. Three experimental methods–radioim-munoassay (RIA), enzyme-linked immunoassay (ELISA), and slot blots–detected no significant cross reactivity between the antibodies and BDNF or NT-3. RIA showed that M15 and N60 recognize the same or an overlapping antigenic site, but 27/21 recognizes a different epitope. Only 27/21, and not N60 or M15, immunoprecipitated β-NGF crosslinked to LNGFR receptor. Thus, the epitope recognized by 27/12 does not overlap the LNGFR receptor binding site. N60, M15, and 27/21 all block binding of NGF to Trk in a manner consistent with competitive inhibition. Purified Fab fragments of N60 and M15 gave similar results to the intact antibodies. The other subunits present in the 7S complex of NGF, i.e. the α and γ subunits, competitively inhibited binding of antibodies to β-NGF. Only the γ subunit inhibited phosphorylation of Trk and biological activity of β-NGF. These findings suggest that the M15, N60, and 27/21 antibodies bind to a specific site on the surface of NGF where they competitively inhibit binding to the Trk NGF receptor. The region encompassing the N-terminus, the C-terminus, and the loop on the surface of β-NGF containing residues 60–80 is proposed as important for binding to the Trk receptoe. © 1994 Wiley-Liss, Inc.     

Intracerebral delivery of a third generation EGFRvIII-specific chimeric antigen receptor is efficacious against human glioma

Chimeric antigen receptors (CAR)-transduced T cells hold great promise in the treatment of malignant disease. Here, we demonstrate that intracerebral injection with a human, epidermal growth factor receptor variant III (EGFRvIII)-specific, third generation CAR successfully treats glioma in mice. Importantly, these results endorse clinical translation of this CAR in patients with EGFRvIII-expressing brain tumors.     

Antisense epidermal growth factor receptor RNA transfection in human malignant glioma cells leads to inhibition of proliferation and induction of differentiation

The epidermal growth factor receptor (EGFR) is a proto-oncogene that is frequently observed with alterations in late stage gliomas, suggesting an important role of this gene in glial tumorigenesis and progression. In this study we evaluated an antisense EGFR approach as an alternative therapeutic modality for glioblastomas. We transfected U-87MG cells with an antisense EGFR construct and obtained several clones stably expressing lower or undetectable levels of EGFR protein. These clones were found to have impaired proliferation as well as a reduced transforming potential to grow in soft agarose. The number of cells positive for the cell cycle-specific nuclear antigen Ki-67 was also significantly decreased ( P <0.05) in antisense EGFR-transfected clones compared with parental or empty vector-transfected cells. Flow cytometric analysis revealed that the proportion of cells in G₀ /G₁ phases of the cell cycle in the antisense clones increased by up to 31% compared with control cells, whereas the proportion of cells in S phase decreased by up to 58%. In addition, the antisense EGFR-transfected cells showed higher expression of glial fibrillary acidic protein and a more differentiated form, with smaller cell bodies possessing fine tapering cell processes. These results suggest that EGFR plays a major role in modulating cell growth and differentiation in glioblastoma cells. Our experimental model of antisense EGFR provides a basis for future development of antisense EGFR oligodeoxynucleotides in treatment of glioblastomas.     

Influence of epidermal growth factor on long-term potentiation in the hippocampal slice

Rat hippocampal slices were perfused with epidermal growth factor (EGF) at a concentration of 10(-8) M. EGF is a well known mitogen which exhibits neurotrophic action on neurons of the CNS. During extra- and intracellular recordings in the pyramidal cell body layer of the CA1-region no influence of EGF on evoked potentials was seen if single-pulse or paired-pulse stimulation was used. Furthermore EGF has no influence on the resting membrane potential of the cells investigated. However after tetanic stimulation a significant increase in the magnitude of long-term potentiation was observed. Therefore it is concluded, that EGF might be involved in modulation of neuronal plasticity.     

神经上皮组织起源的脑肿瘤增殖活性与表皮生长因子受体基因表达的相关性研究

目的　探讨表皮生长因子受体 (EGFR)基因表达与神经上皮组织起源的脑肿瘤增殖活性的关系。　　方法　利用EGFR和Ki-67单抗免疫组化染色及核仁组成区嗜银蛋白 (AgNOR)染色对8例正常脑组织、50例神经上皮组织起源的脑肿瘤和 4个恶性脑肿瘤体外细胞系进行检测。　　结果　神经上皮组织起源的脑肿瘤中EGFR蛋白表达阳性率为 54% ,WHO分级与EGFR蛋白表达呈正相关 (r =0 5597,P <0 0 1 )。Ki-67标记指数 (Ki-67LI)及AgNOR平均数均与神经上皮组织起源的脑肿瘤的分级有明显关系 (r分别为 0 8971和 0 880 1 ,P <0 0 1 ) ,且Ki-67LI与Ag NOR平均数有显著相关性 (r=0 9896,P <0 0 1 )。EGFR蛋白表达阳性的肿瘤组织及细胞系中高Ki-67LI及高AgNOR平均数者占 64 5% ,而无EGFR蛋白表达的肿瘤组织和正常脑组织中高Ki-67LI及高AgNOR平均数者仅为 2 2 6% ,二者间差别有统计学意义 (P <0 0 1 )。　　 结论　神经上皮组织起源的脑肿瘤中EGFR表达与细胞的分裂增殖活动密切相关     

Effects of epidermal growth factor and basic fibroblast growth factor on generation of long-term potentiation in the dentate gyrus of fimbria-fornix-lesioned rats

The effects of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) on long-term potentiation (LTP) in the dentate gyrus in vivo were investigated in fimbria-fornix (FF)-lesioned rats. Transection of FF resulted in decreased frequency of LTP generation. Intracerebroventricular injection of EGF (50 ng) and bFGF (50 ng) significantly facilitated LTP generation in the FF-lesioned rats. These results suggest that EGF and bFGF can promote the hippocampal LTP impaired by loss of subcortical afferents.     

Low serum levels of brain-derived neurotrophic factor and epidermal growth factor in patients with chronic schizophrenia

Neurotrophic factors (NFs) play a pivotal role in the development of the central nervous system. They are thus also suspected of being involved in the etiology of schizophrenia. Previous studies reported a decreased level of serum brain-derived neurotrophic factor (BDNF) in schizophrenia, whereas the association of epidermal growth factor (EGF) with this illness remains controversial. Using a two-site enzyme immunoassay, we conducted the simultaneous measurement of serum BDNF and EGF levels in a group of patients with chronic schizophrenia (N = 74) and a group of normal controls matched in age, body mass index, smoking habit and sex (N = 87). We found that, compared to normal controls, patients with chronic schizophrenia exhibited lower serum levels of both BDNF and EGF across all ages examined (21–59 years). The serum levels of BDNF and EGF were negatively correlated in the controls (r = − 0.387, P = 0.0002) but not in the patients. Clinical parameters such as duration of illness and psychiatric rating scale also showed no robust correlations with the NF levels. Collectively, these results suggest that pervasive, abnormal signaling of NFs underlies the pathophysiology of chronic schizophrenia.     

Epidermal growth factor (EGF)-induced up-regulation and agonist- and antagonist-induced desensitization and internalization of A1 adenosine receptors in a pituitary-derived cell line

This report concerns the study of homologous and heterologous regulation of cell surface A₁ adenosine receptors (A₁R) in a pituitary-derived cell line. This has been possible by the use of the recently developed anti-A₁R antibodies in immunocytochemical assays. Functional desensitization and internalization of A₁R in GH₄ cells occurred after treatment with agonist but also with antagonist. Epidermal growth factor (EGF) treatment led to the up-regulation of cell surface A₁R in GH₄ cells. Confocal analysis evidenced an EGF-induced increase of A₁R present in intracellular clathrin-coated vesicles. The up-regulation was blocked by actinomycin D thus suggesting the involvement of protein synthesis in the effect induced by the growth factor. These results constitute the first example of adenosine receptor regulation by EGF and one of the few examples of antagonist-induced desensitization and internalization among G-protein-coupled receptors.