Expression Of Neuron-specific Enolase Research Articles

Neuroendocrine marker expression in cervical carcinomas of non-small cell type.

Small-cell carcinomas of the uterine cervix are highly aggressive tumors. Up to 100% of these tumors express at least one neuroendocrine marker such as neuron-specific enolase (NSE), chromogranin A (CgA), and synaptophysin (SYN). In other tumor types such as non-small-cell carcinomas of the lung, colon, and prostate, the presence of these markers has been associated with a better prognosis in some studies, a worsened prognosis in others, or has had no prognostic effect in still other studies. However, little is known about their expression and prognostic significance in the common "non-small-cell" carcinomas of the uterine cervix. The primary tumors of 54 previously untreated patients with histologically confirmed non-small-cell carcinoma of the cervix uteri (squamous carcinoma, adenosquamous carcinoma, and adenocarcinoma) were analyzed by immunohistochemistry for expression of NSE, CgA, and SYN. The expression status was correlated to pathological characteristics and outcome. In addition, the expression of these markers was investigated in cervical carcinoma cell lines. None of the 54 tumors expressed NSE or CgA, although SYN was positive in five tumors (9%) of which four were squamous and one was adenocarcinoma. These five patients relapsed within the first 6 months of follow-up and four have died. Among eight cancer cell lines only one was positive for CgA and another one for SYN. We conclude that the neuroendocrine marker SYN is expressed in a small subset of non-small-cell carcinomas of the cervix and its expression seems to correlate with a poor outcome.

Immunohistochemical staining patterns of canine meningiomas and correlation with published immunophenotypes.

This study examined immunohistochemical staining patterns for several meningioma variants involving either the brain or spinal cord of dogs. Formalin-fixed, paraffin-embedded tissue from 15 tumors was obtained. The selected tumor group included seven meningothelial, three transitional, two malignant (anaplastic), one myxoid, one papillary, and one osteomatous meningiomas. Tumors were evaluated for reactivity to the following six immunohistochemical markers: vimentin, pancytokeratin, glial fibrillary acidic protein (GFAP), S100, neuron-specific enolase (NSE), and synaptophysin. Vimentin expression was detected in all meningiomas, and 14 of 15 tumors demonstrated intense vimentin staining in more than 50% of the neoplastic cells. Pancytokeratin expression was present in 11 of 15 neoplasms; however, positive staining frequently was focal and often involved a small percentage of the neoplastic cells. GFAP expression was detected in a single, anaplastic meningioma. Although expression of NSE and S100 was detected in 12 of 25 meningiomas, the intensity of the staining and the percentage of positive neoplastic cells was highly variable. Synaptophysin was uniformly negative. These results will help to establish immunohistochemical profiles for meningiomas that will improve our ability to correctly differentiate these neoplasms of meningeal origin from central nervous system tumors originating from other sites.

Enhanced Expression of Neuron‐specific Enolase (NSE) in Pyothorax‐associated Lymphoma (PAL)

Pyothorax‐associated lymphoma (PAL) is a B‐cell lymphoma of mostly large cell type developing in the pleural cavity of patients with long‐standing pyothorax. Neuron‐specific enolase (NSE) is an enolase comprising γ subunit and is located at high levels in neuronal and neuroendocrine cells, together with their neoplasias. Expression of NSE at protein and mRNA levels was examined in PAL and other types (non‐PAL) of non‐Hodgkin's lymphomas. In PAL, serum levels of NSE were elevated (5.32 to 168.0, mean 42.6 ng/ml) and tended to decrease after incisional biopsy followed by chemotherapy (2.38 to 195.5, mean 34.1 ng/ml). Two cell lines established from two cases of PAL produced and secreted NSE in the culture medium. Immunohistochemistry revealed that the positive rate for NSE staining in PAL (10 of 14 cases, 71.4%) was significantly higher than that in non‐PAL cases (6 of 38 cases, 15.8%) (P<0.01). RT‐PCR analysis showed that the expression levels of NSE mRNA in two cell lines and a biopsy sample from PAL were rather similar to those of the control samples from non‐neoplastic lymph nodes. These findings suggest the posttranscriptional regulation of NSE in PAL. Thus, an elevation of serum NSE level in patients with chronic pyothorax may be an indicator of PAL development.

Expression in the placenta of neuronal markers for perinatal brain damage.

Determination of S-100 a and b and neuron-specific enolase (NSE) in (cord) blood and amniotic fluid has been used to assess neonatal neuronal damage after compromising conditions. However, these proteins are not only found in nervous tissue, and their expression in placenta and umbilical cord has never been investigated. In this study, S-100 (a and b) and NSE expression in human cord and placental tissue was studied by immunohistochemical analysis. Similar analysis was performed using two other brain-specific markers: glial fibrillary acidic protein and growth-associated protein B-50 (also known as GAP-43 or neuromodulin). Tissue was derived after elective cesarean section in seven women of different gestational ages after uncomplicated or complicated pregnancy. S-100 a and b and NSE immunoreactivity was found in several cell types and structures in the umbilical cord as well as in the placenta of all seven cases. Glial fibrillary acidic protein and B-50 showed no immunoreactivity. These data are of importance for interpreting findings of studies in which S-100 or NSE levels in cord blood or amniotic fluid have been related to neuronal damage in the neonate. The increased levels found may just as well be caused by leakage from placenta or umbilical cord as be caused by brain damage. We conclude that S-100 a and b and NSE are not suitable markers for neonatal brain damage. Brain-restricted proteins such as glial fibrillary acidic protein and B-50 seem more promising.

CEA producing primary hepatic carcinoid

Imaging studies of a hepatic tumor in a 53-year-old woman with elevated serum levels of neuron-specific enolase (NSE), carcinoembryonic antigen (CEA) and 5-hydroxyindole acetic acid (5HIAA) revealed a hypervascular tumor in the right lobe. Grossly, the brownish tumor was measured 13.5×12 cm with four daughter nodules. Microscopically, the majority of these columnar and round tumor cells had ribbon-or rosette-like patterns with the expression of neuroendocrine marker proteins, such as Grimelius, NSE, chromogranin A, and synaptophysin, and moderate expression of CEA but without the expression of cytokeratin nos 7,8,14,18,19 and OV-6; the minority had glandular patterns with a strong expression of CEA but without the expression of cytokeratin nos 7,8,14,18,19 and OV-6. Ultrastructurally, most tumor cells contained populations of electron-dense core granules ranging between 100 and 200 nm in diameter. After hepatectomy, serum CEA, NSE, and 5HIAA reverted to normal ranges and persisted for 19 months. These findings suggested that the diagnosis of primary hepatic carcinoid was tenable and that the tumor might derive from hepatic stem cells which acquired the additional nature of producing CEA without cytokeratins characteristic of hepatocytes or bile duct cells. Some molecular based approaches have attributed unique biological behavior and histogenesis to this carcinoid tumor.

Study on the specific expressions of p53, bcl-2 and c-myc in non-small cell lung cancer with neuroendocrine differentiation

To study the specific expression of tumor-related genes (p53, bcl-2 and c-myc) in non small cell lung cancer with neuroendocrine differentiation (NSCLC-NE). The expression of neuron-specific enolase (NSE), chromogranin A (CgA), synaptophysin(Syn), c-myc, bcl-2 and p53 was detected in 60 surgically resected and paraffin-embedded non-small cell lung cancer (NSCLC) specimens by immunohistochemistry (S-P method). The positive rates of NSE, CgA, Syn expressed in 60 cases of NSCLC were 45.00%(27/60), 13.33%(8/60), 31.67% (19/60) respectively. According to the results of these three markers, 41.67%(25/60) of 60 specimens was proved to be as NE differentiation cancer. The NE differentiation in NSCLC was remarkably related to differentiation of tumor cells (P < 0.05). NSCLC-NE had a higher metastatic rate (P < 0.05) and a higher clinical staging (P < 0.05) than NSCLC without NE differentiation. The positive rates of bcl-2, p53 and c-myc expression in NSCLC-NE were 68.00% (17/25), 80.00% (20/25), 68.00% (17/25) respectively, and the expression of bcl-2 and p53 was closely related to NE differentiation (P < 0.05). A certain part of NSCLC have NE differentiation, which has different biological features from NSCLC without NE differentiation. High expression of bcl-2 and mutant p53 can be observed in NSCLC-NE, and bcl-2/Bax unbalance associated with p53 mutation may play an important role in oncogenesis and development of NSCLC-NE.

EWS/Fli-1 Fusion Protein Is Involved in Neural Phenotype in Ewing^|^apos;s Sarcoma Cells

Ewing's sarcoma (ES) and other peripheral primitive neuroectodermal tumor (PNET) show limited neural differentiation and are thought to have a neural crest origin. The fusion gene, EWS/Fli-1 found in ES and PNET are formed by a tumor specific 11; 22 chromosomal translocations. They have been shown to encode a transcriptional activator and promote cellular transformation. However, the precise biological functions of the fusion gene products remain to be elucidated. Especially it is controversial whether the gene products may inhibit neural differentiation or they may keep neural phenotype in ES. In the present study, we first investigated EWS/Fli-1 expression after induction of neural differentiation by addition of nerve growth factor (NGF) or c-AMP and demonstrated that EWS/Fli-1 protein expression did not change in response to those treatments. Moreover, overexpression of EWS/Fli-1 did not affect differentiation process of C6 glial cells. On the contrary, morphological differentiation and expression of NSE (neuron specific enolase) and trkA, one of the high-affinity NGF receptors, were inhibited in ES cells, in which the endogeneous EWS/Fli-1 protein was not detected. In conclusion, our data are compatible with a view that EWS/Fli-1 fusion gene may not inhibit neural differentiation process, but may play an important role in preserving the potentiality of neural phenotype in ES cells.

Expression of S100a, vimentin, NSE, and melan A/MART-1 in seven canine melanoma cells lines and twenty-nine retrospective cases of canine melanoma.

We evaluated the expression of vimentin, S100a, and Melan A/MART-1 (melanoma antigen recognized by T cells 1) in seven cell lines established independently from dogs with canine melanoma. We also compared routine immunostaining of 29 clinical specimens from melanoma cases using vimentin, S100a, and neuron-specific enolase (NSE) with staining for Melan A/MART-1 as part of a diagnostic panel. All the cell lines were positive for expression of vimentin and S-100a. MelanA/MART-1 expression was seen consistently in only two of the seven cell lines. Staining for Melan A/MART-1 was most intense near areas of heavy melanin pigmentation. All except one of the clinical specimens were positive for vimentin. S 100a was expressed in the majority of both pigmented (15/20, 75%) and amelanotic (8/9, 88.8%) tumors. Seventeen of 29 (58.6%) tumors were positive for NSE. Melan A/MART-1 was expressed in 18/29 (62%) tumors, including 90% of pigmented tumors, but in no amelanotic tumors. Intensity of Melan A/MART-1 staining correlated positively with biologic behavior, with seven malignant tumors showing negative to weak staining and 10 benign tumors showing moderate to strong staining. Three malignant tumors showed moderate to intense staining for Melan A/ MART-1. Our results suggest that expression of Melan A/MART-1 may be unstable in cultured cell lines. Assessment of both S100a and Melan A/MART-1 expression is useful to confirm a diagnosis of canine melanoma, and Melan A/MART-1 may be especially informative regarding the biologic behavior of these tumors.

Unaltered expression of Fas (CD95/APO-1), caspase-3, Bcl-2 and annexins in brains of fetal Down syndrome: evidence against increased apoptosis.

Apoptosis is the mechanism by which cells are programmed to die under a wide range of physiological and developmental stimuli. Accumulating evidence indicates that enhanced apoptosis (programmed cell death) in Down syndrome (DS) may play a role in mental retardation and precocious neurodegeneration of the Alzheimer-type. In this regard, alteration of several apoptosis related proteins have been reported in adult DS brain. Fetal DS neurons exhibited increased reactive oxygen species leading to early apoptosis, however, expression of apoptosis related proteins in fetal DS, has never been considered. To address this issue, we investigated the expression of proteins involved in apoptosis including Fas (CD95, APO-1), caspase-3, Bcl-2 and annexins in the cerebral cortex of control and DS fetal brain by western blot and two dimensional electrophoresis. Here, we report that no detectable changes were obtained in fetal DS brain in the expression of Fas, caspase-3, Bcl-2 and Annexins (I, II, V, and VI) compared to controls. In parallel experiment, we also examined the expression of neuron specific enolase (NSE), a neuronal marker found to be decreased in adult DS brain, to see if there is any neuronal loss and no difference was observed between the two groups. Protein expression did not correlate with age. The unchanged levels of Fas, Bcl-2 and annexins together with unaltered caspase-3 expression, a predominant caspase that executes apoptosis in the developing nervous system, suggest that enhanced apoptosis may not be apparent in fetal DS brain as demonstrated for adult DS brain.

STAT3 mediates IL-6-induced neuroendocrine differentiation in prostate cancer cells .

In the human prostate cancer cell line LNCaP, interleukin (IL)-6 has been shown to regulate both growth and neuroendocrine (NE) differentiation. We recently observed that IL-6 mediated growth arrest in LNCaP by activating STAT 3. Since differentiation and growth arrest are often associated processes, we investigated whether STAT3 also mediated NE differentiation in this prostate cancer cell line. We treated previously characterized clones LNCaP-neo (neomycin-resistant LNCaP) and LNCaP-SF (LNCaP-STAT3 dominant negative mutant) with IL-6 and screened for NE differentiation by observing morphological changes and immunoblotting for two NE markers, neuron-specific enolase (NSE) and chromogranin A (ChA). To characterize further the role of STAT3 in growth arrest and differentiation, we transfected a wild-type STAT3 vector into PC-3 cells and generated a subclone PC-3-S3. In this clone, we assessed differentiation by observing morphological changes and determined growth responses by cell counting and clonogenic assays. We observed that IL-6 induced formation of neurite extensions, morphologic features associated with NE differentiation, and enhanced expression of neuronal markers ChA and NSE in LNCaP-neo cells. In contrast, LNCaP-SF, possessing a dominant negative mutant form of STAT3, exhibited no characteristics of IL-6 induced NE differentiation. Furthermore, expression of a constitutively phosphorylated wild-type STAT3 in PC-3 cells inhibited growth and induced the formation of neurite extensions and NSE expression. These results indicate that STAT3 is a mediator of both NE differentiation and growth inhibition in LNCaP and PC-3, suggesting a connection between growth inhibition and NE differentiation in prostate cancer.

Expression of Neuron-Specific Enolase in Adult Rat Brain Following Status Epilepticus

Increased levels of neuron-specific enolase (NSE), a key glycolytic enzyme, in either the cerebrospinal fluid or the serum is correlated with both the duration and the outcome of status epilepticus. To further understand the molecular basis of seizure-induced elevations in NSE protein, we investigated NSE mRNA expression in the adult rat brain following systemic administration of kainic acid. The findings demonstrated either no change or a decrease in NSE gene expression during, and following, status epilepticus, suggesting that posttranscriptional mechanisms are responsible for seizure-induced increases in NSE protein.

Thoracic paravertebral ganglioneuroma with high immunohistochemical expression of TrkA

A 21-year-old man, who had previously undergone a total resection for a retroperitoneal ganglioneuroblastoma at 7 months of age, was revealed to have a thoracic paravertebral ganglioneuroma, in which immunohistochemical expression of neuron-specific enolase and neurofilament was noted. Furthermore, immunohistochemical expression of TrkA, which is a high-affinity receptor for nerve growth factor, was evident. Although the exact histogenesis remains uncertain, TrkA was considered to be involved in the development of this thoracic paravertebral tumor.

Postnatal developmental changes in NSE and NNE mRNA expression in the rat pineal gland: in situ hybridization histochemistry.

By in situ hybridization, neuron-specific enolase (NSE) and non-neuronal enolase (NNE) mRNAs were examined in the rat pineal gland at the postnatal developmental and adult stages. The distributions of hybridized signals were analyzed in comparison with immunohistochemical staining of synaptophysin (SYN), which is a marker for pinealocytes. In SYN-positive areas that were observed throughout postnatal developmental and adult stages, we detected both NSE and NNE signals, which increased simultaneously during early postnatal development and thereafter became stationary. Quantitative analysis revealed that NNE signals were 2- to 3-fold greater in number than NSE signals at any given stage. This predominant expression pattern of NNE differed from that in neurons, which usually showed both signals at similar levels and seemed to reflect the difference in physiological function from neurons. During the early postnatal stages, a cord-like arrangement of cells without distinct SYN staining was observed. This arrangement was the thickest at postnatal day 0 and became dispersed and thinner with development, showing a relationship with formation of vascularized connective tissue stroma. By in situ hybridization, many of the constituent cells showed weak NNE signals but no distinct NSE signals. However, some cells also showed weak NSE signals, suggesting heterogeneity of these cells. The characteristic NSE and NNE expression patterns in the pineal gland cells clarified in this study might provide a basis for further studies of the differentiation and function of the pineal gland.

Effect of taurine on human fetal neuron cells: proliferation and differentiation.

The purpose of this study was to investigate the effect of taurine on human fetal brain neuron cell proliferation and differentiation using a glial-free, pure cerebral neuronal culture grown in a serum-free environment. We found that taurine was necessary for neuronal survival and neurite extension. Taurine, on the other hand, has a trophic effect on the human fetal brain cell, promoting both proliferation and differentiation. Results showed that DNA synthesis of the neurons was increased in a dose-dependent manner when neurons were cultured in the medium containing taurine (100-6400 microM). The protein content of neuronal cells was also significantly increased in the neurons treated with taurine as compared to the control. At day 15, the expression of neuron-specific enolase (NSE) was only detected in the neurons cultured in the medium containing taurine. These results establish taurine as a putative human fetal brain neurontrophic factor in the process of human brain development.

Results after surgery in undifferentiated large cell carcinoma of the lung: the role of neuroendocrine expression

The objective of this study was to define the incidence of light microscopically undifferentiated large cell carcinomas, to analyze tumor stages, types of resections necessary and postsurgical survival. Additionally we tried to evaluate whether or not neuroendocrine expression influences the biological behavior of these tumors. Light microscopic specimens of 105 patients having undergone surgery for undifferentiated large cell carcinoma were reviewed following the 1981 WHO criteria. Fifty eight cases were excluded because elements of adeno- or squamous cell carcinoma, neuroendocrine or combined patterns of histological differentiation were observed. The remaining 47 cases of pure undifferentiated large cell carcinoma were evaluated immunohistochemically for neuroendocrine differentiation using a combination of the markers neuron specific enolase, synaptophysin and chromogranin A. The hospital charts of the patients were analyzed retrospectively recording tumor stage, operative procedure, postoperative complications, postoperative adjuvant treatment procedures, actual tumor state and survival time. Thirteen patients (27.7%) had postsurgical tumor stage I, 5 (10.6%) stage II, 15 (31.9%) stage IIIA, 9 (19.1%) stage IIIB, and 5 (10.6%) stage IV. In 46 of 47 patients resections of lung parenchyma were performed (wedge resection n = 5, segmental resection n = 1, lobectomy n = 27, bilobectomy n = 3, pneumonectomy n = 10), in 6 patients combined with broncho- and/or angioplastic procedures. At the time of chart review 20 (42.5%) patients were still alive. The cause of death in the remaining patients was recurrent lung cancer in the majority of cases (24 or 92.30%). The overall mean survival of the 46 patients undergoing parenchymal resections was 19 months, the 3-year survival rate 31.7%. The immunohistochemical examination demonstrated expression of neuron specific enolase in 15 cases. Synaptophysin and chromogranin A were not detected in any case. For these 15 patients the mean survival was 25.6 months (+/- 4.3) and the 1-year survival rate 67% (confidence interval 43-91%) compared to 13.8 (+/- 2.1) months and 33.5% (confidence interval 15.3-51.7%) in the remainder. The difference was not significant (P = 0.06). The light microscopic diagnosis of undifferentiated large cell carcinoma revealed to be subject to considerable interobserver variability. Undifferentiated large cell carcinoma takes a more unfavorable clinical course than other non-small cell carcinomas. Despite lack of statistical significance, expression of neuron specific enolase appeared to be associated with less aggressive biological behavior of the respective neoplasms. Immunohistochemical evaluation of undifferentiated large cell carcinomas using a combination of neuron specific enolase, chromogranin A, and synaptophysin did not provide more therapeutically relevant information than that obtained by light microscopic assessment.

Expression of two neuronal markers, growth-associated protein 43 and neuron-specific enolase, in rat glial cells.

Recent studies have revealed that proteins such as growth-associated protein 43 (GAP-43) and neuron-specific enolase (NSE), believed for many years to be expressed exclusively in neurons, are also present in glial cells under some circumstances. Here we present an overview of these observations. GAP-43 is expressed both in vitro and in vivo transiently in immature rat oligodendroglial cells of the central nervous system, in Schwann cell precursors, and in non-myelin-forming Schwann cells of the peripheral nervous system. GAP-43 mRNA is also present in oligodendroglial cells and Schwann cells, indicating that GAP-43 is synthesized in these cells. GAP-43 is also expressed in type 2 astrocytes (stellate-shaped astrocytes) and in some reactive astrocytes but not in type 1 astrocytes (flat protoplasmic astrocytes). These results suggest that GAP-43 plays a more general role in neural plasticity during development of the central and peripheral nervous systems. NSE enzymatic activity and protein and mRNA have been detected in rat cultured oligodendrocytes at levels comparable to those of cultured neurons. NSE expression increases during the differentiation of oligodendrocyte precursors into oligodendrocytes. In vivo, NSE protein is expressed in differentiating oligodendrocytes and is repressed in fully mature adult cells. The upregulation of NSE in differentiating oligodendrocytes coincides with the formation of large amounts of membrane structures and of protoplasmic processes. Similarly, NSE becomes detectable in glial neoplasms and reactive glial cells at the time when these cells undergo morphological changes. The expression of the glycolytic isozyme NSE in these cells, which do not normally contain it, could reflect a response to higher energy demands. This expression may also be related to the neurotrophic and neuroprotective properties demonstrated for this enolase isoform. NSE activity and protein and mRNA have also been found in cultured rat type 1-like astrocytes but at much lower levels than in neurons and oligodendrocytes. Thus GAP-43 and NSE should be used with caution as neuron-specific markers in studies of normal and pathological neural development.

Expression pattern of glutamate decarboxylase (GAD) in the developing cortex of the embryonic chick brain

The development of the GABAergic system in the chick embryo telencephalon has been studied. Special emphasis was placed on the development of glutamate decarboxylase (GAD) between embryonic day 8 (E8) and E17. The GABA immunoreactivity and neuron-specific enolase expression was detected simultaneously in glutardialdehyde fixed sections, which confirmed that GABAergic cells exhibit neuronal phenotype. The GAD expression was studied by means of immunohistochemistry on cryo-sectioned material both at the light and electron microscopic levels. Furthermore, the presence and localization of GAD65 and GAD67 mRNAs were studied with an in situ hybridization technique with digoxigenin-labeled RNA probes. Protein expression as well as mRNA appearance mostly coincided both temporally and spatially.In the parahippocampal area, as well as in other regions of the developing cortex, GAD staining was seen from E8 onwards. The number of positive cells increased as did the intensity of staining up to E14. As observed in the electron microscope, the GAD protein was co-localized with GABA in most cases, although some GAD-positive cells devoid of GABA-staining also were observed. The pattern of GAD mRNA expression was in general similar to that of GAD immunostaining. Both GAD65 and GAD67 mRNA were detected during the entire period. Furthermore, GAD67 mRNA localization spatially was more correlated with GAD protein expression. The study provides evidence for the notion that development of the GABAergic system occurs rapidly during embryogenesis and, as suggested from mRNA data, that two forms of GAD with a slight difference in distribution can contribute to this. © 1997 ISDN

BCL2 regulates neural differentiation.

A main function attributed to the BCL2 protein is its ability to confer resistance against apoptosis. In addition to the constitutively high expression of BCL2, caused by gene rearrangement in follicular lymphomas, elevated expression of the BCL2 gene has been found in differentiating hematopoietic, neural, and epithelial tissues. To address the question of whether the expression of BCL2 is a cause or consequence of cell differentiation, we used a human neural-crest-derived tumor cell line, Paju, that undergoes spontaneous neural differentiation in vitro. The Paju cell line displays moderate expression of BCL2, the level of which increases in parallel with further neural differentiation induced by treatment with phorbol 12-myristate 13-acetate. Transfection of normal human BCL2 cDNA in sense and antisense orientations had a dramatic impact on the differentiation of the Paju cells. Overexpression of BCL2 cDNA induced extensive neurite outgrowth, even in low serum concentrations, together with an increased expression of neuron-specific enolase. Paju cells expressing the anti-sense BCL2 cDNA construct, which reduced the endogenous levels of BCL2, did not undergo spontaneous neural differentiation. These cells acquired an epithelioid morphology and up-regulated the intermediate filament protein nestin, typically present in primitive neuroectodermal cells. The manipulated levels of BCL2 did not have appreciable impact on cell survival in normal culture. Our findings demonstrate that the BCL2 gene product participates in the regulation of neural differentiation.

IMMUNOREACTIVE NEURON-SPECIFIC ENOLASE (NSE) IS EXPRESSED IN TESTICULAR CARCINOMA-IN-SITU

Neuron-specific enolase (NSE) is a well-known marker of tumours that have neuroendocrine origin. High levels of NSE have also been described in various types of testicular germ cell neoplasms, particularly in seminomas. To evaluate the presence of NSE in testicular carcinoma-in situ (CIS), a preinvasive stage of testicular germ cell tumours, a panel of CIS tissue specimens was examined. Fifteen of 18 (83 per cent) CIS samples showed immunohistochemical staining with anti-NSE monoclonal antibody. Immunoreactivity has also been found in overt testicular germ cell tumours, including seminomas, non-seminomas, and a mixed germ cell tumour. As the co-existence of high NSE production and gene amplification of N-myc has been reported in some tumours, including germ cell tumours, the expression of the protein product of N-myc was also examined in this study, but only sporadic cases showed N-myc staining. These results are evidence against a relationship between NSE and N-myc in testicular germ cell tumours. The high expression of NSE in CIS and overt germ cell tumours may be due to the increased gene dosage effect associated with the overrepresentation of isochromosome 12p.

Immunocytochemical study of phenotypic plasticity of cultured dorsal root ganglion neurons during development

Rat dorsal root ganglia (DRG) were cultured from different stages of development ranging from embryonic day-14 to adult. The expression of eight neurotransmitter phenotypes was examined with immunocytochemical detection and the percentages of each phenotype were calculated with reference to the whole neuronal population defined by the expression of neuron-specific enolase (NSE). The expression of peptides, calcitonin gene-related peptide (CGRP), substance P (SP), cholecystokinin (CCK) and neuropeptide Y (NPY) was always present whatever the age at onset of the cultures. Although the percentage of CGRP remained stable, that of the other peptides declined progressively. Their in-vitro expression did not differ marked from that found in vivo. Another group of neurotransmiiters, including 5-hydroxytryptamine (5-HT), thyrotropin-releasing hormone (TRH) and gamma-aminobutyric acid (GABA) was never expressed in situ in DRG neurons. In culture, they were expressed in a high percentage of neurons, especially for 5-HT and TRH, and they showed a similar evolution, with a decrease at early postnatal ages followed by a further increase. This profile suggests that the expression of these transmitters is strongly environment-dependent and may be repressed in situ. Finally, somatostatin (SOM) was found only in cultures prepared from adult tissues, whereas it was present in situ from the embryo onwards. The expression of this peptide would thus require a stabilization by a long exposure to environmental factors.We can conclude that the great diversity of phenotypic expression found in DRG neurons in situ is the result of a wide variety of influences occurring at different stages of development in a large potential repertory present in these neurons.