Steroidogenic acute regulatory protein expression in the normal human brain and intracranial tumors

In this study we found the expression of steroidogenic acute regulatory protein (StAR) mRNA and protein in both the normal human brain and intracranial tumors, using RT-PCR and immunohistochemistry. StAR mRNA is expressed at a very low level in the white matter of the normal human brain, but in tumoral tissues StAR mRNA was specifically expressed in oligodendrogliomas and malignant glial tumors. StAR-positive cells were also detected in the normal human brains and gliomas; its frequency and density were higher in glioma tissue. These findings suggest that StAR expression might be correlated with the growth of glial tumors.     

Cellular localization of PDGF mRNAs in developing human forebrain

Platelet-derived growth factor (PDGF) has been implicated in the processes regulating gliogenesis in the CNS. Conflicting in vivo data in rodents have variously implicated either glia or neurons as being the primary source of PDGF. We have used in situ hybridization and immunocytochemical analysis to study the in vivo expression and cellular localization of PDGF-A, sis/PDGF-B, together with the two PDGF receptors α and β, in developing human forebrain. In this study we demonstrate the strong expression of mRNA and protein of both PDGF chains, A and B, and their receptors, α and β, in human embryonic glial cells. The neurons, in contrast to glial cells, expressed lower levels of PDGF and PDGF-receptor mRNAs and protein. Identification of the cell types expressing the PDGF and PDGF-receptor mRNAs was achieved by counterstaining with antibodies specific for glial cells (GFAP) and neurons (NF). The predominant glial-specific expression of both PDGF-A and PDGF-B, together with the coexpression of their receptors α and β, suggests an important role for the PDGF isoforms in the development of human embryonic glial cells and neurons in vivo .     

The PDGF B-chain is involved in the ontogenic susceptibility of the developing rat brain to NMDA toxicity

Hypoxic-ischemic (H-I) injury to neonatal brains can cause a life-long neuronal deficit because of increased susceptibility in the neonatal period. Excitotoxicity due to overstimulation of the N-methyl-d-aspartate receptor (NMDAR) is assumed to be the basis of the injury. However, the ontogenic profile of the susceptibility does not directly correlate with the levels of NMDAR expression. Platelet-derived growth factor B-chain (PDGF-B) has been reported to protect neurons by suppressing the NMDA-evoked current and translocating the glutamate transporter to the cell membrane. Thus, we assessed the relationship between the susceptibility to H-I injury and the expression of PDGF-B in neonatal rat brain. PDGF-B infusion before and after an intrastriatal NMDA injection significantly reduced the size of the lesions in 7-day-old rats, when they are most susceptible and the neuronal expression of PDGF-B is low. Fourteen-day-old neonatal rats were found to be resistant to NMDA injury, even though NMDARs are expressed at high levels in the brain at this age. Inhibition of PDGF-B protein synthesis by antisense oligodeoxynucleotides increased the size of the NMDA-induced lesions up to 6-fold at postnatal day 14, when PDGF-B is expressed at high levels in neurons. These data suggest that PDGF-B is an important physiological modulator of NMDAR excitability in the developing brain, and that the balance between the expression of NMDAR and PDGF-B partly determines the ontogenic susceptibility to brain injury. Enhancement of the PDGF-B/receptor signal pathway might rescue neonatal brains at risk of H-I injury.     

人脑胶质瘤中ING4和CTGF的表达及其意义

目的 探讨人脑胶质瘤中生长抑制因子4(ING4)及结缔组织生长因子(CTGF)的mRNA的表达及其意义.方法 采用荧光实时定量聚合酶链式反应法检测ING4和CTGF mRNA在30例脑胶质瘤组织和5例正常脑组织中的表达水平,统计分析表达水平和肿瘤级别之间的关系以及二者表达水平的相天性.结果 ING4 mRNA在Ⅰ～Ⅱ级...     

EphA2在人脑胶质瘤中的表达及意义

目的：探讨EphA2在人脑胶质瘤组织中的表达水平及其意义。方法：采用反转录PCR和免疫组化法检测EphA2 mRNA和蛋白在126例人脑胶质瘤组织中的表达水平;采用ki67免疫组化染色检测肿瘤组织的增殖水平;采用TUNEL染色检测肿瘤组织的凋亡水平;利用统计学方法分析EphA2表达与肿瘤病理分级、增殖和凋亡之间的相互关系。结果：126例肿瘤标本中,51.6%表达EphA2 mRNA,46.8%表达EphA2蛋白。随着肿瘤分级的升高,EphA2 mRNA和蛋白的阳性表达率显著升高。此外,肿瘤细胞增殖水平与EphA2蛋白表达呈正相关,而其凋亡水平与EphA2蛋白表达呈负相关。结论：EphA2表达水平在人脑胶质瘤组织中显著升高,EphA2表达可能影响胶质瘤细胞的增殖和凋亡。     

Nitric oxide synthase expression and enzymatic activity in human brain tumors

Nitric oxide (NO) is synthesized by NO synthases (NOS), existing in 3 isoforms. NO influences a great variety of vital functions including vascular tone and neurotransmission. Under conditions of excessive formation, NO emerges as an important mediator of neurotoxicity in a variety of disorders of the central nervous system (CNS). Inhibitors of NOS are available that may modify the activity of all isoforms, which may be of clinical relevance. The expression of the 3 NOS isoforms nNOS, iNOS and eNOS and NOS enzymatic activity was examined in 40 patients with primary CNS tumors (gliomas WHO grades I - IV and meningeomas WHO grades I - III) and in 13 patients with metastases from adenocarcinomas or malignant melanomas. A polyclonal antibody directed against nNOS and monoclonal antibodies directed against iNOS and eNOS were used for immunohistochemical staining. NOS enzymatic activity, measured by labeled arginine to citrulline conversion, was assessed in tissue specimens obtained from the same tumors. NOS data were compared with clinical variables and the degree of edema as judged from MR scanning. nNOS expression was increased in tumor cells of glial neoplasms and most pronounced in high-grade tumors, WHO grades III and IV, and in the carcinoma and melanoma metastases. Low-grade gliomas, WHO grades I and II and meningeomas expressed no or only little nNOS. iNOS was only expressed in a few tumors. eNOS was expressed sporadically in the tumor cells while the expression was increased in vascular endothelial cells in both the tumor itself and the peritumoral area of glial neoplasms, and in metastases. eNOS expression was sporadic in endothelial cells of meningeomas. NOS enzymatic activities were heterogeneous among tumor types (0 - 13.8 pmol/min/mg of protein) without correlation to the NOS expression found by immunohistochemical techniques. Likewise, NOS activity and expression was not correlated to the clinical scores or brain edema. In conclusion, nNOS expression may be a putative useful indicator of brain tumor differentiation and malignancy. The enhanced expression of eNOS in vascular endothelial cells of glial neoplasms and metastases raises the possibility that NO production in tumor endothelial cells may contribute to tumor blood flow regulation and possibly brain edema.     

Expression of the neural RNA-binding protein Musashi1 in human gliomas

Tumor cells arising from a particular tissue may exhibit the same gene expression patterns as their precursor cells. To test this proposition, we have analyzed the expression of a neural RNA-binding protein, Musashi1, in primary human central nervous system (CNS) tumors. In rodents, Musashi1 is expressed predominantly in proliferating multipotent neural precursor cells, but not in newly generated postmitotic neurons. The expression of Musashi1 is downregulated with the successive progression of neurogenesis. In normal adult human tissues, we detected low levels of Musashi1 expression in brain and testis by RT-PCR analysis. In an RNA panel of 32 cancer tissues and cell lines, elevated expression of Musashi1 was seen in all five malignant gliomas studied, in contrast to the slight expression seen in other tumor cells, including those in several melanomas and a prostate cancer. Western blot analysis showed strong Musashi1 expression in malignant gliomas compared with nonneoplastic brain tissue. Glioblastomas, the most malignant form of glioma, showed higher Musashi1 expression than less malignant gliomas by immunohistochemical analysis. Tumors with strong Musashi1 expression tended to have high proliferative activity. Thus, the expression of Musashi1 correlated with the grade of the malignancy and proliferative activity in gliomas. These results suggest that primary CNS tumors may share gene expression patterns with primitive, undifferentiated CNS cells and that Musashi1 may be a useful marker for the diagnosis of CNS tumors.     

VEGF在人脑胶质瘤中的表达与肿瘤增殖及肿瘤血管生成的关系

目的研究血管内皮细胞生长因子(vascular endothelial growth factor,VEGF)在人脑胶质瘤中的表达与肿瘤增殖及血管生成的关系。方法应用免疫组化技术和形态定量分析法,检测98例手术切除脑胶质瘤中VEGF表达、PCNA标记指数(PCNA LI)、微血管密度(Microvessel density,MVD)表达。结果(1)肿瘤细胞及血管内皮细胞均可以表达VEGF,阳性颗粒分布于肿瘤胞浆中;(2)高级别肿瘤PCNA、LI、MVD显著高于低级别肿瘤(P<0.05);VEGF表达阳性肿瘤的PCNA、LI、MVD显著高于VEGF表达阴性肿瘤(P<0.05);(3)在星形细胞肿瘤中,随着MVD的增大,VEGF在肿瘤血管内皮的染色率逐渐增加,与肿瘤的MVD存在正相关关系(r值为0.44,P<0.01)。结论脑胶质瘤的VEGF表达与MVD呈正相关关系,VEGF在肿瘤细胞增殖及血管再生过程中起重要作用。     

Human von Willebrand factor (factor VIII-related antigen) in glial neoplastic cells of brain gliomas

In order to determine whether the glial neoplastic cells within the brain gliomas show human von Willebrand factor (factor VIII-related antigen [FVIII-rA]) expression, and the possible distribution of FVIII-rA positive glial cells within the neoplasm, morphological examination and computerised morphometric analysis were conducted in 35 brain neoplasms, divided into 2 groups: glioblastoma multiforme (15 cases) and astrocytoma II (20 cases). Only in glioblastomas was the expression of FVIII-rA within the glial neoplastic cells found to be significantly higher than in background. The groups of FVIII-rA positive glial cells were usually found near the vascular glomeruloid structures. On the basis of the examination, the following conclusions were drawn: at least a part of the glial neoplastic cells within the glioblastoma multiforme may present expression of FVIII-rA; lack of FVIII-rA expression in the glial cells of astrocytomas II suggests that the activity of FVIII-rA within these cells is connected with the malignancy of gliomas; the role of FVIII-rA positive glial cells remains unknown, but the tendency to location near the vascular glomeruloid structures of glioblastomas might suggest their potential functional connection with endothelial cells.