Neuron specific protein (NSP) in neuroblastoma cells: relation to differentiation

Determination of Phosphofructokinase and Enolase Activities in Cultured Mouse Neuroblastoma Cells: Application to the In Vitro Detection of Neurotoxic Effects

Simple methods for the determination of phosphofructokinase (PFK) and total enolase (END activities in cultured mouse neuroblastoma cells have been developed. The influences of changes in glucose metabolism, induced by chlorpromazine, cycloheximide, 2,4-dinitrophenol and iodoacetic acid, on PFK and ENL activities in vitro were compared as a practical application of the methods. Mouse neuroblastoma cell cultures (Neuro-2a) were exposed for 24 hours and cytotoxic effects were evaluated. All the determinations were carried out in the same 96-well tissue culture plates in which exposure took place. Chlorpromazine and cycloheximide produced opposite effects on both PFK and ENL activities. While chlorpromazine increased PFK activity by 50% and decreased ENL activity by 30%, cycloheximide inhibited PFK activity by 50% and increased ENL activity by 45%. The response to dinitrophenol was quite different; both PFK and ENL activities were increased, by 45% and 35% respectively. After exposure of the cells to iodoacetic acid, neither PFK nor ENL activities showed statistically significant differences from the levels in control cells. The different responses elicited by the four toxicants suggest that the two enzymes selected are useful for differentiating among diverse types of mechanism of action.

Characterization of alginate/chitosan-based nanoparticles and mathematical modeling of their SpBMP-9 release inducing neuronal differentiation of human SH-SY5Y cells

The incidence of brain degenerative disease such as Alzheimer's disease (AD) will increase as the world population is ageing. While current AD treatments have only a transient effect, there are many evidences indicating that some growth factors, such as BMP-9, may be used to treat AD. However, growth factors cannot readily access the brain because of their size and the presence of the blood brain barrier. We have therefore developed a small peptide derived from BMP-9, SpBMP-9, which can promote the differentiation of cholinergic neurons and inactivate GSK3beta, a Tau kinase. Here, we investigated the potential of a nanoparticle-based delivery system of SpBMP-9, made of alginate and chitosan (Alg/Chit NPs), as a new therapeutic strategy against AD. The Alg/Chit NPs size distribution revealed NPs with an average diameter of ∼240nm. The encapsulation efficiency of SpBMP-9 was ∼70% of the initial peptide mass loading. Release kinetics of SpBMP-9 were performed in physiological conditions and modelled with a mechanistic framework that took into account the size distribution of Alg/Chit NPs. The release of SpBMP-9 revealed to be mostly diffusive, but there were interactions between the peptide and the alginate chains. The Alg/Chit NPs could also increase the viability of SH-SY5Y cells in comparison to the control. Finally, the SpBMP-9 released from Alg/Chit NPs promoted the SH-SY5Y differentiation into mature neurons as demonstrated by a higher neurite outgrowth and an increased expression of the neuronal markers NSE and VAchT. In conclusion, the nano-scale SpBMP-9 delivery system made of Alg/Chit may be a promising therapeutic strategy against AD.

Transition between isozymic forms of enolase during in vitro differentiation of neuroblastoma cells-II

An analysis of enolase expression during differentiation of neuroblastoma clones in homogeneous culture is presented. The enolases expressed in these neuroblast-like cells are identical to those of mouse brain with respect to the examined properties. Our biochemical investigation has premitted us to demonstrate formally that neuroblastoma cells undergo a transition from the embryonic ?? form to the neuronal ?? form and contain both enolases as well as the ?? hybrid form during maturation. These results suggest that the same phenomenon must exist in vivo for neuroblasts. In neuroblastoma cells, an increase in both ?? and ?? neuron specific enolases is related to cell maturation and expression of the ?? form precedes that of the ?? form during differentiation. Modulation of neuronal enolase activities is similar in the various conditions of differentiation studied and appears not to be necessarily related with morphological differentiation, although concomitant with an arrest of cell division. The evolution of specific neuronal enolases in neuroblastoma cells parallels that observed in vivo, in brain from embryonic day 15 to post-natal day 7. Moreover, at least one treatment (dimethylsulfoxide) causes an important decrease in the high specific ?? activity of these cells as occurs in vivo. This enolase can therefore also be considered as a biochemical marker for neuroblastoma maturation. As observed with other markers and other cell types, neuroblastoma cells in culture express an immature biochemical differentiation of the enolase isozymes.

Biochemical and electrophysiological differentiation profile of a human neuroblastoma (IMR-32) cell line

A human neuroblastoma cell line (IMR-32), when differentiated, mimics large projections of the human cerebral cortex and under certain tissue culture conditions, forms intracellular fibrillary material, commonly observed in brains of patients affected with Alzheimer's disease. Our purpose is to use differentiated IMR-32 cells as an in vitro system for magnetic field exposure studies. We have previously studied in vitro differentiation of murine neuroblastoma (N1E-115) cells with respect to resting membrane potential development. The purpose of this study was to extend our investigation to IMR-32 cells. Electrophysiological (resting membrane potential, V(m)) and biochemical (neuron-specific enolase activity [NSE]) measurements were taken every 2 d for a period of 16 d. A voltage-sensitive oxonol dye together with flow cytometry was used to measure relative changes in V(m). To rule out any effect due to mechanical cell detachment, V(m) was indirectly measured by using a slow potentiometric dye (tetramethylrhodamine methyl ester) together with confocal digital imaging microscopy. Neuron-specific enolase activity was measured by following the production of phosphoenolpyruvate from 2-phospho-d-glycerate at 240 nm. Our results indicate that in IMR-32, in vitro differentiation as characterized by an increase in NSE activity is not accompanied by resting membrane potential development. This finding suggests that pathways for morphological-biochemical and electrophysiological differentiations in IMR-32 cells are independent of one another.

A comparative study of the distribution of alpha- and gamma-enolase subunits in cultured rat neural cells and fibroblasts

We report the presence and distribution of alpha (ubiquitous) and gamma (neuron-specific) subunits of the dimeric glycolytic enzyme enolase (2-phospho-D-glycerate hydrolase) in cultured neural cells. The gamma gamma enolase is found in vivo at high levels only in neurons and neuroendocrine cells. Neuronal cells in culture also contain relatively high levels of alpha gamma and gamma gamma enolase. Here we show, by enzymatic and immunological techniques, that the gamma subunit also is expressed in cultured rat astrocytes and meningeal fibroblasts and, as we previously reported, in oligodendrocytes. Both neuron-specific isoforms alpha gamma and gamma gamma are expressed in all these cells, but the alpha alpha isoform accounts for the major part of total enolase activity. The sum of alpha gamma and gamma gamma enolase activities increases with time in culture. i.e. maturation processes, reaching the highest level in oligodendrocytes (40% of total enolase activity) and 15 and 10% of total enzymatic activity in astrocytes and fibroblasts, respectively. The gamma enolase transcripts were found not only in cultured neuronal cells but also in cultured oligodendrocytes astrocytes, and meningeal fibroblasts. Our data indicate that neuron-specific enolase should be used with caution as a specific marker for neuronal cell differentiation.

Phosphodiesterase specific inhibitors control cell growth of a human neuroepithelioma cell line

The effects of cyclic nucleotide phosphodiesterase (PDE) inhibitors on cell proliferation of SK-N-MC human neuroepithelioma cell line was studied. Clonal density experiments in the presence of 100 microM rolipram and zaprinast showed respectively 27% and 91% inhibition. The effects of PDE inhibitors were then investigated on crude cell extracts; the calculated IC50 were 32 microM for zaprinast and 16 nM for DC-TA-46; the latter inhibitor was used instead of rolipram for its higher efficacy. Dose-response experiments in clonal density conditions showed IC50 of 5 microM and 1.8 microM in the presence respectively of zaprinast and rolipram. These data show that both inhibitors are effective in reducing cell growth, although the response was quantitatively different.

Axotomy induces intranuclear immunolocalization of neuron-specific enolase in facial and hypoglossal neurons of the rat

Neuron-specific enolase as an enzyme of the glycolytic pathway is localized in the cytoplasm of nerve cells, but not in the cell nucleus. We have applied immunocytochemistry with 1:64,000 polyclonal anti-rat neuron-specific enolase to the brainstem of male and female adult Wistar rats following: (a) transection of the facial nerve with immediate microsurgical nerve suture (facial-facial anastomosis), (b) transection of the hypoglossal nerve with immediate suture (hypoglossal-hypoglossal anastomosis) and (c) transection of the facial and hypoglossal nerve with immediate suture of the proximal hypoglossal to the distal facial nerve stump (hypoglossal-facial anastomosis). Studying the intracellular immunolocalization of neuron-specific enolase in neurons of the facial and hypoglossal nucleus we detected that (1) in normal rats about 20% of all facial and hypoglossal neurons display not only cytoplasmic, but also intranuclear neuron-specific enolase-like immunoreactivity and (2) following any axotomy of the facial or hypoglossal peripheral nerve, the perikarya of all injured motoneurons react by an outstanding increase of neuron-specific enolase-like immunoreactivity in the karyoplasm. Similar findings were obtained in experiments on non-fixed cultured Neuro-2a cells that had been lesioned with hydrogen peroxide. Counting the absolute numbers of normal and reactive neurons at 1-365 days post axotomy revealed that the increase of neuron-specific enolase in neuronal cell nuclei is temporary and reversible. It is first detected at 2 days post axotomy, reaches its maximum at 10-18 days post axotomy and is no longer evident 56 days following surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuron and glial cell marker proteins as indicators of heavy metal-induced neurotoxicity in neuroblastoma and glioma cell lines

The sensitive and specific biochemical indicators for assessing chemical-induced neurotoxic insults in cell culture models have not been sufficiently explored. This study was designed to assess the usefulness of glia-specific beta-S100 protein and neuron-specific enolase (NSE) as indices of in vitro neurotoxicity of heavy metals. Glioma C6 and neuroblastoma N18TG-2 cells were grown in Dulbecco's modified Eagle's medium containing various concentrations of mercuric chloride (HgCl2) or cadmium chloride (CdCl2) for 5 days. Toxic response patterns of the neurospecific endpoints (beta-S100 and NSE), which were monitored with enzyme immunoassays, were compared with those of the non-neurospecific endpoints such as cell viability, total cellular protein, lactate dehydrogenase (LDH) activity, and cumulative glucose consumption in the two cell lines. Both HgCl2 and CdCl2 produced dose-dependent inhibition of neurospecific endpoints and non-specific endpoints. However, by ranking the EC50 values (effective concentration producing half-maximal inhibition) for various endpoints, the lowest values were found for beta-S100 in C6 cells, and for NSE in N18TG-2 cells. In lower and intermediate concentrations, the inhibitory effects of the heavy metals on the content of beta-S100 and NSE occurred in the absence of any detectable effect on intracellular LDH activity, and independently of total cellular protein inhibition. The sensitive and excess responses of the neurospecific endpoints relative to that of the non-specific endpoints may reflect the specific neurotoxic insults of the heavy metals on the cultured cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential expression of neuron-specific enolase mRNA in mouse neuroblastoma cells in response to differentiation inducing agents

1. The mouse neuroblastoma cell line N-115 was used as a model system to study neuronal differentiation induced by treatment of cells with different agents. 2. The extent of morphological differentiation obtained with dibutyryl cyclic AMP (dbc-AMP), dimethyl sulfoxide (DMSO), retinoic acid (RA), and serum-free medium was correlated to the expression of the mRNA for the gamma isoform of the glycolytic enzyme enolase, a recognized neuron-specific marker. 3. A 4-day treatment of the cells with any of the differentiation inducing agents used in this study resulted in the extension of long neurites, though differences in cell body shape were observed depending on the agent used. 4. Northern blot analysis revealed that changes in the level of gamma enolase-specific mRNA correlate with the extent of morphological differentiation, with a 5- to 20-fold increase depending on the differentiation inducing agent used. 5. Finally, we found that a high cell density causes a significative increase in the level of the gamma enolase-specific message in cells maintained in growing conditions.

Serum biological markers and paraneoplastic syndromes in Wilms tumor

Various tumors secrete tumor-specific substances capable of producing signs and symptoms in host organs not caused by direct tumor invasion or organ destruction. These symptoms are collectively referred to as "remote effects" or "paraneoplastic syndromes" of malignancy. Paraneoplastic syndromes are uncommon in childhood cancer. In Wilms tumor several distinct paraneoplastic syndromes have been reported: hypertension, erythrocytosis, hypercalcemia, Cushing syndrome, and acquired Von Willebrand disease. In addition some tumor-specific substances are known to be elevated in patients with a malignancy without causing specific symptoms. These so called "tumor markers" can be used to detect early recurrence in previously treated patients, or in the evaluation of patients undergoing adjuvant therapy. Five of particular interest are erythropoietin, neuron-specific enolase (NSE), hyaluronic acid (HA), hyaluronic acid-stimulating activity (HSA), and hyaluronidase.

Gamma enolase expression as early marker of neuronal differentiation of murine neuroblastoma cells N-115

In this study we determined the levels of gamma enolase mRNA in mouse neuroblastoma cell line N-115 at early period of induction of differentiation by serum withdrawal. The expression of gamma enolase was examined by Northern blot analysis of total RNA extracted from cells induced for different lengths of time. We found a 3-fold increase in the level of gamma enolase mRNA after 24 hours of induction of differentiation and higher levels were detected in cells induced for longer time, reaching a 10-fold increase after four days.

Temporal and compartmental restriction of neuron-specific enolase expression in the rat mesostriatal system

The striatum and the mesencephalic dopamine neurons which innervate it, are each organized into developmentally and biochemically distinct compartments. Striatal patches, characterized in the neonate by high concentrations of opiate receptors and substance P, are innervated prenatally by fibers originating in one group of midbrain dopamine neurons, the ventral tier. By the third postnatal day, a dense dopamine projection from neurons in the dorsal tier of the mesostriatal group innervates non-patch areas of the striatum, i.e. the matrix, and is followed by the appearance there of neurotensin, somatostatin and calcium binding protein. We have recently observed that the period of establishment of connections between dorsal tier dopamine neurons and their target cells in the striatal matrix is accompanied by a surge in expression of the gene coding for tyrosine hydroxylase (TH). In order to determine the overall metabolic state of mesencephalic and striatal neurons during the period of up-regulation of TH gene expression, we have applied immunocytochemistry for neuron specific enolase (NSE), and cytochrome oxidase histochemistry, known markers for neuronal activity, as well as TH immunohistochemistry to the mesencephalon and striatum of postnatally developing rats. At birth, both NSE and cytochrome oxidase were expressed almost exclusively in the patches, appearing in the matrix only after the 2nd postnatal day. Patches of NSE remained visible thru the 14th day. In the mesencephalon, cytochrome oxidase and immunoreactive NSE cells in adjacent sections, were present only in the pars reticulata (i.e. ventral tier). By day 8, both techniques identified nigral cells in the dorsal as well as ventral tiers.(ABSTRACT TRUNCATED AT 250 WORDS)

A combined evaluation of biochemical and morphological changes during human neuroblastoma cell differentiation

1. The effects of retinoic acid, gamma-interferon, cytosine arabinoside, nerve growth factor, tumor necrosis factor, and 12-O-tetradecanoylphorbol 13-acetate on the human neuroblastoma cell line, LAN-5, were studied. Intracellular levels of acetylcholinesterase, neuron-specific enolase, catecholamines and related neurotransmitters, vasointestinal peptide, and substance P were evaluated after induction. 2. Cell morphology was strongly affected by retinoic acid, gamma-interferon, cytosine arabinoside, and 12-O-tetradecanoylphorbol 13-acetate. The main effects of retinoic acid and gamma-interferon were the loosening of cell clusters and the extension of long neurites; cytosine arabinoside induced cell body swelling and marked neuritogenesis. Following 12-O-tetradecanoylphorbol 13-acetate treatment, the cells became small, round, and neuritic. Conversely, modifications induced by nerve growth factor and tumor necrosis factor were mild. Cell proliferation rate was reduced by retinoic acid, gamma-interferon, cytosine arabinoside, and 12-O-tetradecanoylphorbol 13-acetate, while nerve growth factor and tumor necrosis factor were devoid of effects. 3. Acetylcholinesterase activity was significantly stimulated by retinoic acid and by gamma-interferon. Neuron-specific enolase activity was unaffected by all treatments except 12-O-tetradecanoylphorbol 13-acetate, which enhanced it by 1.6-fold. 4. The cellular catecholamine and related metabolite content was lowered by retinoic acid and gamma-interferon, while cytosine arabinoside and, even more, 12-O-tetradecanoylphorbol 13-acetate showed a stimulatory activity on their intracellular accumulation. 5. Finally, the cell-associated vasointestinal peptide level was strikingly increased by gamma-interferon and, to a lesser extent, by retinoic acid, cytosine arabinoside, and 12-O-tetradecanoylphorbol 13-acetate. 6. It is concluded that the most relevant biochemical changes associated with LAN-5 cells differentiation involve the repertoire of neurotransmitters and neuropeptides. These events vary in quality and in quantity, likely due to the pattern complexity of gene expression triggered by each inducer in determining the diversity of neuronal phenotypes.

Neuron-specific enolase reflects metabolic activity in mesencephalic neurons of the rat

Numerous studies on the local rate of energy metabolism of various brain regions during development and following experimental manipulation have been conducted using 2-deoxyglucose uptake and cytochrome oxidase (CO) histochemistry, both considered to be reliable indicators of long-term and short-term alterations in neuronal activity, respectively. Another method which has been related to neuronal activity is neuron-specific enolase (NSE) immunohistochemistry. An isoenzyme of enolase, a key element in the glycolytic pathway, NSE is present in neurons and neural-related cells e.g. neuroendocrine cells, pituicytes, and many tumor cells, but not in glia. The distribution on adjacent tissue sections of immunoreactive NSE and histochemically determined CO were mapped in the rat mesencephalon and adrenal medulla. Both methods showed highly restricted localization of staining which coincided with few exceptions in the most reactive areas, namely the superior colliculus, medial and lateral geniculate nuclei, red nucleus, lateral mammillary nucleus, interpeduncular nucleus and substantia nigra pars lateralis and pars reticulata. Immunoreactivity of varying intensity for NSE was also observed in perikarya and in processes of numerous scattered neurons throughout the mesencephalon, including the substantia nigra pars compacta, and reticular formation. The general correspondence in staining patterns between CO and NSE in the midbrain, supports the utility of NSE as a useful index of metabolic activity in neurons.

Neuroectodermal tumor of bone. Evidence for neural differentiation in a cultured cell line

A new cell line was established from a "neuroectodermal tumor of bone" affecting the right scapula of an 18-year-old man. The original neoplasm had dense proliferation of small round cells with abundant glycogen content and numerous Homer-Wright rosettes. The culture showed proliferation of small spindle cells with uniform oval nuclei and slender cytoplasmic processes. When the culture reached maximum density, rosette-like structures similar to those in the original tumor were formed. Under the influence of N6,O2'-dibutyryl adenosine 3',5'-cyclic monophosphoric acid (dibutyryl cAMP), the cultured cells expressed these rosette-like structures even in the lower cell concentration. Electron microscopy revealed that the cultured cells treated with dibutyryl cAMP contained high-density granules, well-developed microtubules, and abundant 10-nm filaments. By immunocytochemistry, neuron-specific enolase (NSE), and N-myc oncogene product were detected in the cultured cells as well as the original tumor. These results indicated the neuroectodermal origin of some of the small round cell tumors of bone.

Immunocytochemical and ultrastructural studies of the histogenesis of Ewing's sarcoma and putatively related tumors

The histogenesis of Ewing's sarcoma (EW) and extraskeletal Ewing's sarcoma (EEW) is still disputable. Their relationship to the so-called Askin's tumor, neuroectodermal tumor of bone, and peripheral neuroblastoma remains to be established. In an attempt to clarify these points, immunocytochemical and ultrastructural studies were done on tissues from 14 cases of EW, 4 cases of EEW, and 9 cases of primitive neuroectodermal tumor (PNET) and compared with neuroblastoma and olfactory neuroblastoma. Six tumors categorized initially as EW and EEW on biopsy, turned out to be PNET by extensive histologic and/or ultrastructural observations. Abundant glycogen was recognized not only in 16 of 18 cases of EW and EEW, but also in seven of nine cases of PNET. Fine fibrillar cell processes were seen between tumor cells, at least in limited areas even in cases of EW and EEW. Immunocytochemically, neuron-specific enolase (NSE), neuroblastoma cell surface antigen (NBCA), neuron cell surface antigen (NCSA), and neurofilament (NF) were demonstrated not only in neuroblastoma, but also frequently in cases of EW, EEW, and PNET. The results seem to suggest that EW and EEW represent the most immature forms of neuroectodermal tumor. Electron microscopic study showed predominantly primitive cells with occasional areas of cell processes, neurosecretory granules, and microtubules, suggesting a neuroectodermal origin.

Paragangliomas: assessment of prognosis by histologic, immunohistochemical, and ultrastructural techniques

To predict clinical outcome, we studied 42 paragangliomas from 37 patients by routine histology, immunohistochemistry, and electron microscopy. A panel of antisera to neuron-specific enolase (NSE), chromogranin, and met-enkephalin was used to identify chief (type I) cells, and S-100 protein and glial fibrillary acid protein (GFAP) sustentacular (type II) cells. The intensity of staining of type I cells and the density of type II cells were assessed semiquantitatively (0 to 4+) in a total of 38 tumors. A total of 23 of 24 low-grade tumors (solitary, multiple, or associated with other neoplasms; 95.8%) contained type II cells immunoreactive with either S-100 protein or GFAP, and all were positive when S-100 protein and GFAP were used in combination. Five of the nine intermediate-grade (recurrent and/or locally aggressive) tumors were identified as glomus jugulare tumors (GJT). Three intermediate-grade GJTs were devoid of GFAP-reactive type II cells and four GJTs were negative for S-100 protein. Type II cells were identified in only one of five high-grade (malignant) paragangliomas and that tumor contained vanishingly rare cells that were weakly S-100 protein positive but GFAP negative. Sustentacular cell density and chief cell staining intensity were both inversely related to tumor grade. The most sensitive chief cell marker was NSE (92.1%), followed by chromogranin (84.2%). The least sensitive (73.0%) and specific marker was met-enkephalin. Combinations of NSE or chromogranin with met-enkephalin identified chief cells in all cases. Electron microscopy identified neurosecretory granule-containing chief cells, but was of less value in delineating sustentacular cells because of their scarcity and the absence of specific features. By comparison, immunohistochemistry was superior in identifying sustentacular cells. The use of an immunohistochemical panel, in addition to routine histology, can confirm the diagnosis of a paraganglioma and can give an indication of the likely prognosis for a patient.

Poorly differentiated, neuron-specific enolase positive round cell tumor with two translocations t(11;22) and t(21;22)

The authors describe a highly malignant, disseminated round cell tumor originating in the ninth rib of a 14-year-old boy. Extensive studies by means of light and electron microscopic examination, histocytochemistry and immunocytochemistry and cytogenetic analysis revealed an undifferentiated, neuron-specific enolase positive round cell tumor with a unique karyotype: 45,XY,-21,t(11;22)(q23;q11), der(22)t(21;22)(q11.2;p11). Thus, despite the absence of definite morphologic features, such as Homer-Wright rosettes, neurosecretory granules and cytoplasmatic processes, these findings suggest a neuroectodermal origin of this bone tumor.

Medulloblastomas in childhood: histological factors influencing patients' outcome

Sixty-five medulloblastomas in infancy and childhood treated from 1965 through 1981 were reviewed, and the correlation between histological findings of medulloblastomas and clinical course of the patients was studied. Thirty-five patients died but the remaining 30 are alive and without clinical evidence of recurrence 5 years or more after surgery. Certain histological features on light microscopic examinations (e.g., pleomorphism of tumor cells, nuclear-cytoplasmic ratio, mitotic index, degree of vascularity and endothelial proliferation) do influence patient outcome with statistical significance (P less than 0.05). Thirty out of 65 medulloblastomas were examined further, using immunohistochemical methods with glial fibrillary acidic protein (GFAP), neuron specific enolase (NSE), and factor VIII/vW factor (F VIII/vWF). GFAP stain was negative in 20%, NSE stain in 13.3% and F VIII/vWF stain in 16.7% of the medulloblastomas studied. "Desmoplastic" medulloblastomas showed a strong tendency toward positive NSE and GFAP staining in the glomerular portion. There was no correlation between patient outcome and the results of applied immunohistochemical studies. Our data indicate that certain histological features may influence patient outcome, but the degree and pattern of cellular differentiation do not predict outcome.

Serum neuron-specific enolase in children with neuroblastoma. Relationship to stage and disease course

Serum neuron-specific enolase (NSE) was measured in 61 children at diagnosis with all stages of neuroblastoma. The median serum values for Stages I, II, III, IV, and IV-S were 13, 23, 40, 214, and 40 ng/ml, respectively. Mean serum levels were different between groups I versus IV, (P = 0.0004) II versus IV (P = 0.0001) and IV-S versus IV (P = 0.004). The prognostic value of serum NSE for disease-free survival was determined in 54 patients at risk for relapse 2 or more years after diagnosis. The disease-free survival rate of all patients with levels of less than 100 ng/ml was 27/34 (79%), whereas it was 2/20 (10%) for those with higher levels. In 28 patients with lower stage disease and a good prognosis (Stages I, II, and IV-S) NSE levels were not predictive of relapse. Only 1 of these 28 patients had a raised level (greater than 100 ng/ml) and survived without relapse, whereas 4 patients who relapsed had serum NSE less than 100 ng/ml at diagnosis. In patients with Stages III and IV disease, a raised serum NSE level was associated with poor outcome: only 1/19 (5%) survived with NSE levels greater than 100 ng/ml, whereas survival was 5/8 (63%) with values below 100 ng/ml. Serial samples were analyzed on 17 patients; all 8 patients with initial NSE levels greater than 100 ng/ml achieved near normal levels during remission (median, 21 ng/ml). However, in only 4/10 patients studied at time of relapse, did the levels rise coincident with relapse. The sera of 47 patients with other forms of cancer and 19 siblings of cancer patients were at or near the normal limits (0-15 ng/ml), with three exceptions: acute lymphoblastic leukemia (286 ng/ml), hepatoblastoma (176 ng/ml), and primitive neuroectodermal tumor (105 ng/ml). Serum NSE is a useful marker for patients with advanced neuroblastoma in whom elevated levels were associated with a poor outcome; the raised NSE levels returned to near normal after therapy. In patients with Stage IV-S disease serum NSE levels were significantly lower than those in Stage IV despite their extensive tumor burden. Serum NSE estimation may confirm Stage IV-S status and suggest a more benign clinical course.

Normal and malignant neural cells: a comprehensive survey of human and murine nervous system markers

Tumor-associated neural markers are finding increased application in diagnostic histopathology and in the development of brain tumor therapy. The major cell-type-specific markers and monoclonal antibodies that identify murine and human neural cells are reviewed in this study. Monoclonal antibodies, raised against fetal and adult neural tissue, neuroectodermal tumor tissue, or cell line immunogens which recognize epitopes on brain tumors are comprehensively described including antigens common to the nervous, hematopoietic, and immune systems. The clinical application of neural cell markers and monoclonal antibodies for the diagnosis, localization, and treatment of neuroectodermal tumors is reviewed.

Developing rat brain binds monoiodinated insulin isomers similarly to other extrahepatic target tissues

We recently reported a series of binding and metabolic studies which led to the conclusion that the developing rat brain is a target tissue for insulin. Since insulin target tissues (extrahepatic) are capable of differentiating between various monoiodoinsulin isomers, we measured the binding of the B26 monoiodoinsulin isomer compared to the A14 in newborn rat brain preparations to determine if the developing rat brain shared the same relative binding of these isomers (viz. B26 greater than A14) with other extrahepatic tissues. The B26 isomer bound 1.57, 1.50 and 1.34 times as much as did the A14 to brain membranes, glia and neurons, respectively, whereas both isomers were bound equally by liver plasma membranes. Competition-inhibition curves were generated using homologous unlabeled (127I) insulin isomers. Binding of the B26 isomer was greater than the A14 at all concentrations. Scatchard plots showed that the receptor concentrations for the two isomers were similar, and affinity profiles showed that the differences in binding could be accounted for by the greater affinity of the receptors for the B26 isomer. The results indicate that the developing rat brain shares with other extrahepatic insulin target tissues a greater affinity for B26 monoiodoinsulin isomer compared to A14. Future studies of insulin binding should avoid using mixtures of iodinated insulins so that a uniform interpretation of data is made possible.

Factors involved in expression of neuron-specific and non-neuronal enolase activity in developing chick brain and in primary cultures of chick neurons

The effect of various factors affecting non-neuronal enolase (NNE) and neuron-specific enolase (NSE) was investigated in developing brain of two different chick strains, in primary cultures of pure neurons and of mixed cultures of neuronal and glial cells. NNE and NSE activities reached their maximum at an earlier stage of brain development in the fast growing Hybro strain than in the Leghorn strain. In pure neurons cultured during 6 days, NNE was stimulated by hydrocortisone in presence or in absence of serum. Dibutyryl cyclic AMP (diBcAMP) stimulated NNE only in serum-free medium. NSE activity was increased by glial cell-conditioned medium in presence of serum and by removal of serum from the medium. Hydrocortisone and diBcAMP had no effect on NSE. In mixed cultures of neurons and glial cells both enolase activities were raised in absence of serum. Hydrocortisone and diBcAMP had no effect. Steroid hormones, insulin and serum albumin also modify both enolase activities in pure neurons and in mixed cultures of neurons and glial cells. Our results suggest that NNE and NSE are regulated separately by various factors involved in nerve cell maturation.

Enolase isozymes in differentiated and undifferentiated medullary thyroid carcinomas

Enolase isozyme composition was studied using both electrophoretic and chromatographic methods in rat medullary thyroid carcinomas (MTC), differing in their degree of differentiation. In well-differentiated rat tumors (DMTC), both the alpha- and gamma-subunits of enolase were expressed, resulting in alpha alpha, alpha gamma, and gamma gamma isozymes. The relatively high amount of alpha gamma and gamma gamma isozymes (neuron-specific enolase [NSE] ) was indicative of the presumed neuroectodermal origin of these tumors. In contrast, highly undifferentiated or anaplastic tumors (AMTC) were characterized by a decrease in expression of the gamma-subunit. Hence, the majority of enolase isozymes were alpha alpha dimers, with only a few percent alpha gamma hybrids remaining. These shifts from neuron-specific to non-neuronal isozymes in rat MTC were compared with human MTC and discussed with respect to neuronal differentiation and the clinical significance of NSE measurements in serum as a marker for amine precursor uptake and decarboxylation cell-derived neoplasms.

Immunohistochemical demonstration of neuronal and astrocytic differentiation in retinoblastoma

Sections of 51 surgically enucleated eyes from cases of retinoblastomas were examined immunohistochemically to delineate patterns of cellular differentiation. Employing the avidin-biotin immunoperoxidase technique, antibodies were used against glial fibrillary acidic protein (GFAP), S-100 protein and neuron specific enolase (NSE). Areas of uninvolved retina and/or optic nerve were used as built-in positive control. Most of the tumors showed GFAP and S-100 protein-positive perivascular glial cells that were interpreted as reactive astrocytes. In three well-differentiated retinoblastomas, glial cells were found to be interspersed randomly among tumor cells and not associated with blood vessels. These glial cells were interpreted as neoplastic based on their distribution pattern and cytologic features. In about half of the tumors, the retinoblastoma cells stained positively for NSE, indicating their neuronal tumor cells that stained positively for NSE but failed to show any evidence of photoreceptor differentiation. Based on these observations and similar differentiation patterns described in other primitive neuroectodermal tumors of the brain, it is suggested that retinoblastoma cells can differentiate not only into photoreceptor cells but also along other neuronal cell lines and rarely into glial cells.

Enolase distribution in human brain tumors, retinoblastomas and pituitary adenomas

The cellular localization of alpha-, beta- and gamma-subunits of enolase isoenzyme was studied immunohistochemically in various human brain tumors, retinoblastomas and pituitary adenomas (total, 91 cases). The alpha-subunit was found in almost all brain tumors except in medulloblastoma cases. A case of medullomyoblastoma contained beta-subunit-positive myoblastic cells, which was also positive for human myoglobin. The gamma-subunit was frequently observed in medulloblastomas, retinoblastomas and pituitary adenomas. However, gamma-subunit was also present in some non-neuronal brain tumors such as astrocytomas and oligodendrogliomas. Enzyme immunoassay technique also confirmed the presence of gamma-subunit in a medulloblastoma and two retinoblastomas.

Isozyme pattern of enolase of childhood tumors

Retinoblastoma, neuroblastoma, and medulloblastoma have many common features, clinical as well as histologic; a common embryonic origin has been suggested. The authors studied the electrophoretic pattern of enolase (EC 4.2.1.11) in these tumors. All tumors were characterized by the presence of three types of enolase, designated as alpha alpha, alpha gamma and gamma gamma. The latter is supposed to be the neuron-specific enolase. Normal adult brain and adult retina show the same set of isozymes (alpha alpha, alpha gamma and gamma gamma). In contrast, gliomas of childhood, tumors originating from the supportive tissue of the central nervous system, are characterized mainly by the presence of the alpha alpha dimer and a small amount of the alpha gamma hybrid. The results of this report support the hypothesis of a common embryonic origin of retinoblastoma, neuroblastoma, and medulloblastoma.

Neuron-specific enolase in the diagnosis of neuroblastoma and other small, round-cell tumors in children

Immunocytochemical staining for neuron-specific enolase (NSE) was performed in 44 round-cell tumors from children by the improved immunoglobulin-enzyme bridge method with antiserum against NSE. The tumors studied consisted of 15 neuroblastomas showing various degrees of histologic differentiation, 13 Ewing's sarcomas, ten soft tissue sarcomas of diverse origin, and six lymphomas of bone and soft tissues. Neuron-specific enolase was detected in all neuroblastomas, irrespective of the degree of histologic differentiation. None of the other round-cell tumors was positive for NSE, except one embryonal rhabdomyosarcoma that contained differentiated myoblasts. The primitive cells of this tumor were negative as well. It is concluded that immunocytochemical staining with antibodies to NSE is a practical and reliable method for distinguishing neuroblastomas from other nonneural round-cell tumors in children. This is true even for the most primitive forms of neuroblastomas, in which morphologic techniques are less reliable. Neuron-specific enolase may also be useful in delineating the neural histogenesis of other ill-defined tumors.

Human neuron-specific enolase: genetic and developmental studies

Neuron-specific enolase is readily detected as early as 54 days gestational age in brain extracts from human fetuses and undergoes a rapid increase with developmental maturation of the nervous system. No genetic variants of this enzyme were found among 14 fetal and 120 postnatal specimens, consistent with previous findings of highly restricted variation among glycolytic enzymes.

Raised neuron-specific enolase in serum of children with metastatic neuroblastoma. A report from the Children's Cancer Study Group

Serum levels of neuron-specific enolase (NSE) were measured by radioimmunoassay at diagnosis in 122 children with widespread metastatic neuroblastoma (clinical stage IV). 96% of these patients had NSE levels more than three standard deviations above the mean for age-matched normal children. Mean serum NSE was 207 +/- SD257 ng/ml (range 10-1240 ng/ml), whereas that in normal age-matched children was 7.5 +/- 2.1 ng/ml (range 5.4-12.9 ng/ml). Analysis of survival in relation to the level of NSE at diagnosis suggested that serum levels greater than 100 ng/ml were associated with a poor outcome. This relation was highly significant in the subgroup of infants less than 1 year old at diagnosis; all 7 with serum NSE below 100 ng/ml were alive up to 36 months after diagnosis, whereas 7 of 8 with serum NSE above 100 ng/ml died within 12 months of diagnosis. Serum NSE may be a useful disease marker and a prognostic indicator in children with metastatic neuroblastoma.

Neuroblastoma and the differential diagnosis of small-, round-, blue-cell tumors

Of the solid tumors of childhood, neuroblastoma--the prototypic small-, round-, blue-cell neoplasm--occurs in the youngest patients and has shown the least predictable biologic behavior and response to therapy. It is often confused clinically and histologically with Wilms' tumor, rhabdomyosarcoma, lymphoma, and especially, Ewing's sarcoma. Certain clinical and histologic features that may be useful in prognosis have been identified, however, and a variety of distinctive light microscopic, electron microscopic, and immunohistochemical features may be useful in differentiating this and related tumors. Many of the varied techniques useful in the differential diagnosis of these tumors can now be employed routinely in most laboratories.

On the Application of Cultured Neuronal Cell Lines in Neurotoxicological Studies: Implications of Acrylamide-induced Neurite Disintegration

Summary

Cultures of the mouse neuroblastoma cell line C1300, clone N1E115 were exposed to acrylamide at 3.5 x 10-4M for 14 days (subacute situation) or at 2.8 x 10-3 M for 24 hr (acute situation).

In the subacute situation the total uptake of 2-deoxy-D-glucose was stimulated. This could be explained by an increase in both the non-specific diffusion and the specific transport. The activity of the glycolytic enzyme, enolase (EC4.2.1.11), was unaffected by exposure to acrylamide, whereas the activity of glyceraldehyde-3-phosphate-dehydrogenase (EC1.2.1.12) was inhibited. Acrylamide had a marked stimulating effect on the respiratory activity of the cells, whereas the incorporation of tritiated leucine remained unchanged. Furthermore, membrane integrity was maintained throughout the acrylamide exposure as judged by an unchanged rate of 2-deoxy-D-glucose-6-phosphate efflux. Corresponding results were obtained in the acute situation. In N1E115 cultures and under the experimental conditions used in this work acrylamide caused neurite degeneration resembling distal axonopathy in vivo. It is suggested that these degenerative changes are not due to a general intoxication of the cells, but rather to a specific effect. Consequently, the N1E115 cell line might be useful in studies of chemically-induced axonopathies.

Long-term effects of brain trypsinization before cell seeding on cell morphology and surface composition

The relation between the pattern of proteins localized in the surface of astroglial cells and cell differentiation was investigated in primary cultures derived from neonatal rat brains, dissociated either mechanically (MDC) or by 3 (TDC3) and 30 minutes (TDC30) trypsinization. Morphological and ultrastructural studies revealed a bed layer composed of flat, polygonal young and differentiated astrocytes in all types of cultures and a surface layer composed of small, ovoide undifferentiated cells which were more numerous in TDC30 than in TDC3 and MDC. The enrichment in undifferentiated cells, induced by prolonged brain trypsinization prior cell seeding, was observed during two weeks in culture; latter, by day 20, the cell population in all cultures was that of differentiated astrocytes. The presence of structural and enzymatic cell markers indicated that the cell population in MDC and TDC3 as well as in TDC3, including the small cells, was of astroglial origin. Concomitant with the morphological changes, cells in TDC30 were less accessible to surface labeling than those composing MDC. Subsequent electrophoresis of the labeled surface proteins demonstrated that a 140-130 K complex was the most "sensible" to brain trypsinization and that their accessibility to the surface probing was maximal during the differentiation of astrocytes in MDC or of small cells in TDC30. By day 20, these components were not significantly labeled in both, MDC, and TDC30, cultures. The use of two types of astrocytes primary culture which were different in the ratio of differentiated to undifferentiated cells and their surface labeling at different growth stages showed a variation in the composition of surface proteins during the cell maturation. The increased accessibility of some surface proteins to external probing when the cells developed to differentiated astrocytes might suggest their involvement in cell differentiation.

Localization of insulin-like immunoreactivity in the neurons from primary cultures of rat brain

Brains from 1-day-old rats were dissociated with trypsin and the cells were maintained in culture for 3-4 weeks. These primary cultures contained insulin-like immunoreactivity in the limited populations of neurons. Typically, the fluorescent staining pattern observed in the soma was homogeneous and varicosity-like structures were observed on the neurites of the majority of insulin-like immunoreactive neurons. Serum deprivation of brain cell cultures did not reduce immunoreactivity, whereas cycloheximide caused approx. 80% decrease in the number of insulin-like immunoreactive neurons. Incubation of these cultures with [3H]valine resulted in the incorporation of radioactivity into immunoprecipitable insulin. These results suggest that insulin-like immunoreactivity present in the Central Nervous System (CNS) neurons may be synthesized by brain cell cultures.

A developmental study of neuron-specific enolase in rat adrenal medulla

The levels of neuron-specific enolase (NSE) in rat adrenal medulla increase with age. A sharp increase was observed until the age of 15 days. At this time, the NSE level dropped slightly, followed by a gradual increase until the rats were 1 year old. The adrenal medullary NSE levels in males were higher than those observed in females. The difference was seen from 32 days of age, but was not statistically significant until 1 year. This study indicates that NSE can be used as a marker for differentiation in adrenal medulla, as it is used in the central nervous system and in neuroblastoma and pheochromocytoma cells.

Butyrate-induced increase in neuron-specific enolase and ornithine decarboxylase in anaplastic glioma cells

Butyrate treatment results in the rapid formation of processes on F98 anaplastic glioma cells. The morphological differentiation occurs more rapidly and to a greater extent than that induced by nerve growth factor (NGF). The incorporation of [3H]thymidine is virtually stopped 1 day after treatment of F98 cells with sodium butyrate. Butyrate also caused a large increase in ornithine decarboxylase activity in F98 cells between 6 and 12 h after treatment. This was inhibited by both cycloheximide and actinomycin-D. NGF did not cause these effects. Butyrate also caused an increase in neuron-specific enolase (NSE) content in F98 cells. This effect appeared to be specific for butyrate. Since NSE induction is characteristic only of neurons and neuroendocrine cells, this finding indicates that butyrate is capable of inducing biochemical differentiation along neuronal lines in undifferentiated glioma cells.

Neuron-specific and non-neuronal enolase in developing chick brain and primary cultures of chick neurons

Developmental changes of the neuron-specific enolase (NSE) and the non-neuronal enolase (NNE) were determined in pure neuronal, or mixed cultures of neuronal and glial cells, prepared from brains of 8-day-old chick embryos, as a function of cellular development with time in culture. The modifications observed in culture were compared to those measured in brain during the development of the nervous tissue in the embryo and during the post-hatching period. In the whole brain, the total enolase activity increases progressively until the adult level, the NSE appears only 4 days before hatching. The total enolase activity of pure neurons increases until 8 days of culture but the NSE never appears during this period. Mixed cultures of neurons and glial cells present an increase of total activity until 14 days of culture and neuron-specific form of the enzyme can be observed after 6 days of culture. Our results suggest that NSE appears only in the functional brain and is expressed in cultivated neurons only when glial cells are present simultaneously.

High levels of immunoreactive nervous system-specific enolase in sera of patients with neuroblastoma

Serum levels of nervous system-specific enolase (NSE, gamma gamma form plus alpha gamma form) in patients with neuroblastoma and in control subjects were determined with a sensitive solid-phase sandwich enzyme immunoassay system. Serum levels of NSE in healthy adults ranged from 1.4-5.7 ng/ml (2.87 +/- 1.18 ng/ml, n = 20), and in control children (1-7 years old) from 2.6 to 10.8 ng/ml (5.76 +/- 2.42 ng/ml, n = 20). Serum samples (n = 13) from patients with neuroblastoma contained high levels of NSE, range 13.6 to 330 ng/ml (mean 96 ng/ml); however those (n = 7) from ganglioneuroblastoma patients were within a normal range (3.0-25.0 ng/ml; mean 8.3 ng/ml). These results suggested that the NSE in serum might be a valuable marker substance for screening and therapeutic monitoring of neuroblastoma.

Development of neuron-specific enolase immunoreactivity in avian nervous tissue in vivo and in vitro

Neuron-specific enolase (NSE) is a glycolytic isoenzyme that is primarily located in neurons and neuroendocrine cells. The development of NSE immunoreactivity in th avian nervous system at the level of the hind limb has been examined using immunocytochemical methods. NSE immunoreactivity is first detected in ventral horn motor neurons and dorsal root ganglion neurons at embryonic day 9-10. This is at least 2-3 days after some neurons in both these populations are capable of electrical activity. The glycogen body, a non-neuronal structure, also exhibits NSE (+) staining, but the onset of this immunoreactivity is earlier, at 8 days of embryonic development. NSE immunoreactivity was absent from the cell bodies of paravertebral sympathetic ganglia throughout development, but was present in cellular processes and terminals in the adult ganglia. NSE immunoreactivity also develops in tissue cultures containing cells of neural tube and neural crest origin.

Neurone specific enolase: an aid to the diagnosis of melanoma and neuroblastoma

Melanoma and neuroblastoma are diagnosed by their clinical and histological features, including evidence of melanogenesis and neural differentiation respectively, by tumour cells. These criteria are occasionally inadequate. Melanoma and neuroblastoma are derived from a system of cells characterized by the content, precursor uptake and decarboxylation of particular amines (APUD cells). Neurone specific enolase (NSE) has been proposed as a specific marker for neural elements and APUD cells. Immunohistochemical cytoplasmic and fibrillary localization of this enzyme was demonstrated in formalin-fixed, paraffin-processed sections of melanoma and neuroblastoma, constituting and additional aid to the identification of these tumours. The demonstration of an enzyme of the glycolytic pathway within tumour cells has implications following the effects of anti-tumour agents and these are discussed.