myelin-basic-protein and Cell-Transformation--Neoplastic

Topics: Amoeba; Animals; Antigens, Neoplasm; Bacteria; Bacteriophages; Binding Sites, Antibody; Blood Platelets; Cell Membrane; Cell Transformation, Neoplastic; Erythrocytes; Eye Proteins; Fungi; Glycoproteins; HeLa Cells; Histocompatibility Antigens; Immunoglobulins; L Forms; Liver; Macrophages; Myelin Basic Protein; Nerve Tissue Proteins; Orthomyxoviridae; Porifera; Sindbis Virus; Viruses

Many studies have suggested that the 3D organization of chromatin and proteins within the nucleus contributes to the regulation of gene expression. We tested multiple aspects of this nuclear organization model within a primary cell culture system. Oligodendrocyte lineage cells were examined to facilitate analysis of nuclear organization relative to a highly expressed tissue-specific gene, proteolipid protein (PLP), which exhibits transcriptional upregulation during differentiation from the immature progenitor stage to the mature oligodendrocyte stage. Oligodendrocyte lineage cells were isolated from brains of neonatal male rodents, and differentiation from oligodendrocyte progenitors to mature oligodendrocytes was controlled with culture conditions. Genomic in situ hybridization was used to detect the single copy of the X-linked PLP gene within each interphase nucleus. The PLP gene was not randomly distributed within the nucleus, but was consistently associated with the nuclear periphery in both progenitors and differentiated oligodendrocytes. PLP and a second simultaneously upregulated gene, the myelin basic protein (MBP) gene, were spatially separated in both progenitors and differentiated oligodendrocytes. Increased transcriptional activity of the PLP gene in differentiated oligodendrocytes corresponded with local accumulation of SC35 splicing factors. Differentiation did not alter the frequency of association of the PLP gene with domains of myelin transcription factor 1 (Myt1), which binds the PLP promoter. In addition to our specific findings related to the PLP gene, these data obtained from primary oligodendrocyte lineage cells support a nuclear organization model in which (1). nuclear proteins and genes can exhibit specific patterns of distribution within nuclei, and (2). activation of tissue-specific genes is associated with changes in local protein distribution rather than spatial clustering of coordinately regulated genes. This nuclear organization may be critical for complex nucleic-acid-protein interactions controlling normal cell development, and may be an important factor in aberrant regulation of cell differentiation and gene expression in transformed cells.

Topics: Active Transport, Cell Nucleus; Animals; Animals, Newborn; Binding Sites; Cell Compartmentation; Cell Differentiation; Cell Lineage; Cell Nucleus; Cell Transformation, Neoplastic; Cells, Cultured; DNA-Binding Proteins; Fluorescent Antibody Technique; Gene Expression Regulation, Developmental; Male; Myelin Basic Protein; Myelin Proteolipid Protein; Nuclear Proteins; Oligodendroglia; Rats; Ribonucleoproteins; Stem Cells; Transcription Factors

Ras-transformed cells often show high levels of expression of activating protein-1 and Ets and of genes regulated by these transcription factors. In analogy with the effects of transient stimulation of Ras, it is assumed that the increase in transcription-factor transactivation in stably transformed cells is due to Ras-induced constitutive activation of mitogen-activated protein kinases. However, this has not been extensively studied. Using specific substrate peptides, we have examined here the activities of two types of mitogen-activated protein kinase, extracellular-signal-regulated kinase (ERK) and Jun N-terminal kinase (JNK), in [Val12]Ras-transformed rat embryo fibroblast cell lines. These activities were elevated 2-3-fold in Ras-transformed cells compared with non-transformed cells with a similar growth rate. Increased ERK activity was not necessarily accompanied by a similar increase in JNK activity. In transformed cells, ERK and JNK activities could be stimulated fourfold and ninefold by phorbol ester and ultraviolet-light treatment, respectively, indicating that only a fraction of these enzymes were constitutively activated in these cells. It has been suggested that inactive JNK downregulates c-Jun transcriptional activity by binding to the c-Jun delta-domain. No decrease in delta-inhibitor activity could be demonstrated in Ras-transformed cells compared with control cells, consistent with the presence of mainly inactive JNK in transformed cells. Treatment of transformed cells wih benzodiazepine 5B, an inhibitor of Ras farnesylation, decreased ERK and JNK activities, and concomitantly caused morphological reversion, reduced growth rate, and normalization of transformation-related gene expression. We conclude that in stably Ras-transformed cells the moderately increased ERK/JNK activities are not coregulated, and that ERK rather than JNK activity correlated with transformation-related gene expression.

Topics: Animals; Benzodiazepines; Blotting, Northern; Blotting, Western; Calcium-Calmodulin-Dependent Protein Kinases; Cell Line, Transformed; Cell Transformation, Neoplastic; Genes, ras; Histones; Humans; JNK Mitogen-Activated Protein Kinases; Mitogen-Activated Protein Kinases; Myelin Basic Protein; Proto-Oncogene Proteins c-jun; Rats; RNA, Messenger; Signal Transduction; Tetradecanoylphorbol Acetate; Transcription Factors; Transcriptional Activation; Tumor Cells, Cultured

We have taken a transgenic approach in an effort to specifically transform oligodendrocytes, the myelinating glial cells of the central nervous system (CNS). Transgenic mice were generated with a DNA construct that contained the activated neu oncogene under the transcriptional control of the myelin basic protein (MBP) gene. The MBP/c-neu transgenic animals have experienced a low incidence of brain tumors that express molecular markers specific to oligodendrocytes, providing a mouse model to study the formation and progression of oligodendrocyte tumors. A tumor from a transgenic animal has been dispersed in culture, and transformed cells that express properties of oligodendrocytes and astrocytes have been maintained. The degree to which these cells express phenotypic characteristic of oligodendrocytes or astrocytes is influenced by culture conditions. These transformed cells should serve as a valuable resource with which to study various molecular and biochemical aspects of the myelination process, as well as the lineage interrelationship of CNS glial cells.

Topics: Animals; Astrocytes; Base Sequence; Biomarkers; Biomarkers, Tumor; Brain Neoplasms; Cell Differentiation; Cell Transformation, Neoplastic; Gene Expression Regulation; Genes, Synthetic; Glioblastoma; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Mice, Transgenic; Molecular Sequence Data; Myelin Basic Protein; Neoplasm Proteins; Nerve Tissue Proteins; Oligodendroglia; Oncogenes; Organ Specificity; Phenotype; Promoter Regions, Genetic; Proto-Oncogene Proteins; Receptor, ErbB-2; Recombinant Fusion Proteins; Tumor Cells, Cultured

To establish the neuroendocrine and neural features of peripheral neuroblastic tumors, a prospectively collected group of 12 neuroblastomas (NB), 2 ganglioneuroblastomas (GNB), and 4 ganglioneuromas (GN) was probed with a panel of monoclonal antibodies (MAbs) to neuroendocrine and neural antigens. All tumors expressed the pan-neuroendocrine markers synaptophysin and chromogranin A. They also showed extensive expression of neuronal antigens, ie, of each of the neurofilament (NF) triplet proteins and of the microtubule-associated proteins (MAPs) MAP2 and tau-protein. However, only in the GNBs and GNs was the pattern of NF phosphoisoforms relatively mature. In the latter tumors glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP) could be demonstrated as well, suggesting the presence of nonmyelinating and myelinating Schwann cells, respectively. The glial markers did not colocalize with the neural markers. On the basis of these data, it was concluded that all peripheral neuroblastic tumors manifest molecular characteristics of neuroendocrine cells and of neurons. The latter were most developed in GNBs and GNs, in which they were accompanied by Schwann cell differentiation in a separate population of cells. The above-outlined neuronal profile of peripheral neuroblastic tumors, including NBs, distinguishes this group of tumors from the much-less neuronally differentiated primitive neuroectodermal tumors of the central nervous system.

Topics: Abdominal Neoplasms; Adrenal Gland Neoplasms; Adult; Antibodies, Monoclonal; Biomarkers, Tumor; Cell Differentiation; Cell Transformation, Neoplastic; Child; Child, Preschool; Chromogranin A; Chromogranins; Female; Ganglioneuroma; Glial Fibrillary Acidic Protein; Humans; Immune Sera; Immunohistochemistry; Infant; Intermediate Filament Proteins; Intermediate Filaments; Male; Membrane Proteins; Microtubule-Associated Proteins; Myelin Basic Protein; Nerve Tissue Proteins; Neuroblastoma; Neurons; Phosphorylation; Schwann Cells; Synaptophysin; tau Proteins

A case of cerebellar medulloblastoma with clusters of mature ganglion cells and glial cells is described. The patient, a 15-year-old girl, underwent three operations followed each time by radiation and chemotherapy during the four-year clinical course. Histologically, the ganglion cells were clearly identifiable by their abundant eosinophilic cytoplasm, round nuclei with prominent nucleoli, tigroid granules, and argyrophilic fibrils and axons. Immunohistochemically, the cells were NSE- and NF-positive, and ultrastructurally they contained abundant tubules and filaments, neurosecretory granules and well developed rough endoplasmic reticulum. There were many cells transitional in appearance between primitive cells and mature ganglion cells. The tumor also had many mature yet atypical astrocytes and oligodendrocytes. The exact mechanism of the extensive neuronal and glial maturation of medulloblastoma cells is unclear, but the repetitive surgical interventions, radiation and chemotherapy might have had certain cytostatic effects on rapidly dividing medulloblastoma cells, giving them a chance to mature into postmitotic cells with potential for neuronal and glial differentiation.

Topics: Adolescent; Cell Transformation, Neoplastic; Cerebellar Neoplasms; Female; Ganglia; Glial Fibrillary Acidic Protein; Humans; Immunohistochemistry; Intermediate Filament Proteins; Medulloblastoma; Microscopy, Electron; Myelin Basic Protein; Neuroglia; Phosphopyruvate Hydratase; S100 Proteins

Neurofibromas are often clinically, as well as histologically, indistinguishable from completely neurotized melanocytic nevi. We tested the hypothesis that immunologic markers would differentiate the perineural fibroblasts and Schwann cells of neurofibromas from the neurotized cells of melanocytic origin. We examined eight partially neurotized acquired melanocytic nevi, three partially neurotized congenital melanocytic nevi, and five neurofibromas, with antibodies directed against S-100 protein, Leu-7(HNK-1), glial fibrillary acid protein (GFAP), and myelin-basic protein (MBP). A histologic diagnosis of neurofibroma was based on identification of a dermal proliferation of spindle-shaped cells with wavy nuclei, in a background of loose reticulated collagen. Neurotized nevi were diagnosed upon recognition of scattered nests of type A or B nevus cells, surrounded by basement membrane, present in the papillary dermis of lesions otherwise indistinguishable from neurofibromas. The congenital nevi were all large melanocytic nevi known to be present at birth. S-100 stained the majority of neoplastic cells in all neurofibromas, neurotized acquired nevi, and neurotized congenital nevi. Neurofibromas showed focal staining for Leu-7, GFAP, and MBP. In contrast, neurotized acquired and congenital nevi failed to express these markers. We believe that Leu-7, GFAP, and MBP may be helpful in differentiating neurofibromas from completely neurotized melanocytic nevi. The differences in the immunohistochemical profiles of neurofibromas and neurotized nevi support the concept that these neoplasms are histogenically distinct, despite their similar histologic appearance.

Topics: Antigens, Differentiation; Antigens, Surface; Biomarkers, Tumor; Cell Transformation, Neoplastic; Glial Fibrillary Acidic Protein; Humans; Immunohistochemistry; Killer Cells, Natural; Melanocytes; Myelin Basic Protein; Neurofibroma; Nevus, Pigmented; S100 Proteins; Skin Neoplasms; Staining and Labeling

Fourteen nevi with neuroid zones were examined and compared with nine nevi without neuroid structures. At light microscopic level, nevus cells from the neuroid nevi and the control nevi show the same staining pattern with polyclonal antibodies against S-100 protein. Around the cells of the neuroid zones is a more intensive immunoreactivity with monoclonal antibodies against laminin and collagen type IV than around the nevus cells in the upper dermis and the nevus cells in the control nevi. Also, the Gordon-Sweet stain for reticulin shows a dense network around the cells of the neuroid zones. No immunoreactivity in the neuroid zones was found with monoclonal antibodies against myelin-basic protein, myelin-associated protein, and glial fibrillary acidic protein. At the electron microscopic level, nevus cells from the neuroid zones show stacks of elongated cytoplasmic processes surrounded by basal lamina material. This pattern explains the presence of the abundant cytoplasm seen at light microscopy. Because no features of neural or neurolemmal differentiation could be found, the exactitude of the term neurotization can be questioned.

Topics: Antigens, Surface; Biomarkers, Tumor; Cell Transformation, Neoplastic; Collagen; Cytoplasm; Histocytochemistry; Humans; Laminin; Melanocytes; Microscopy, Electron; Myelin Basic Protein; Myelin Proteins; Myelin-Associated Glycoprotein; Nevus; S100 Proteins; Schwann Cells; Skin Neoplasms

Subependymal giant cell astrocytomas associated with tuberous sclerosis were studied with immunostains for glial fibrillary acidic protein (GFAP), myelin basic protein (MBP) and neuron-specific enolase (NSE). Tumor tissue was composed of three forms of cells; polygonal, ovoid and fusiform. A polygonal form was large in size and contained a vesicular nucleus, a distinct nucleolus and scarce Nissl granules resembling a nerve cell. An ovoid cell was similar to a gemistocytic astrocyte. Glial fibers stained with PTAH were observed to surround the tumor cell cluster. Immunocytochemically the polygonal cells were GFAP-and NSE-positive, the ovoid cells were GFAP-, MBP- and NSE-positive, and the fusiform cells were sometimes GFAP- and NSE-positive. The origin of tumor cells remains controversial, either glial or neuronal. This tumor occurs commonly in the subependymal region where germinal matrix cells appear at the early developmental stage. These results suggest that subependymal giant cell astrocytoma could have the totipotential to differentiate to astrocytic, oligodendrocytic as well as neuronal cells.

Topics: Astrocytoma; Brain Neoplasms; Cell Transformation, Neoplastic; Child; Female; Glial Fibrillary Acidic Protein; Humans; Immunoenzyme Techniques; Male; Myelin Basic Protein; Phosphopyruvate Hydratase; Tuberous Sclerosis