Stable formation of mutated p53 multimers in a Chinese hamster cell line causes defective p53 nuclear localization and abrogates its residual function.

We have previously described a methotrexate-resistant cell line (MTX M) characterized by amplified dihydrofolate reductase (DHFR) genes, cytoplasmic p53 localization, and p53 stable tetramers. To investigate the p53 functionality in MTX M, the effect of chemical/physical agents was studied. In MTX M cells, DNA damage did not induce p53 or mdm-2 protein, while in the parental V79 cells, a residual p53 activity was found.

Quaternary assembly and crystal structure of GDP-D-mannose 4,6 dehydratase from Paramecium bursaria Chlorella virus.

GDP-D-mannose 4,6 dehydratase is the first enzyme in the de novo biosynthetic pathway of GDP-L-fucose, the activated form of L-fucose, a monosaccharide found in organisms ranging from bacteria to mammals. We determined the three-dimensional structure of GDP-D-mannose 4,6 dehydratase from the Paramecium bursaria Chlorella virus at 3.8A resolution.

Genome analysis and gene expression profiling of neuroblastoma and ganglioneuroblastoma reveal differences between neuroblastic and Schwannian stromal cells.

Neuroblastic tumours are a group of paediatric cancers with marked morphological heterogeneity. Neuroblastoma (Schwannian stroma-poor) (NB-SP) is composed of undifferentiated neuroblasts. Ganglioneuroblastoma intermixed (Schwannian stroma-rich) (GNBi-SR) is predominantly composed of Schwannian stromal (SS) and neuroblastic (Nb) cells.

The three-dimensional structure of beta2 microglobulin: results from X-ray crystallography.

beta2-microglobulin, the light chain component of the major histocompatibility complex I, is involved in the development of DRA, an amyloid deposition disease occurring in man. Specifically, the beta2-microglobulin component, dissociated form the complex heavy chain, gives rise to amyloidogenic deposits in the joints of patients exposed to long dialysis periods. beta2-microglobulin three-dimensional structure is based on an antiparallel beta-barrel fold, with immunoglobulin domain topology, displaying structural flexibility in the crystal and NMR structures so fare determined.

Application of microarray-based technology to neuroblastoma.

In the past decade, microarray technology has become a major tool for high-throughput comprehensive analysis of gene expression, genotyping and re-sequencing applications. High-throughput microarrays are used for expression profiling analyses with the aims of gene or pathway discovery, tumor subclassification or relapse risk assessment. The introduction of microarray CGH provides a powerful tool to precisely detect and quantify genomic aberrations and map these directly onto the human genome.

Oligogenic inheritance in neuroblastoma.

Neuroblastoma (NB), a childhood malignancy affecting neural crest deriving cell lineages, is characterized by great clinical variability and histological heterogeneity. As NB usually occurs as sporadic form, molecular studies were mainly carried out on tumor samples and derived cell lines, leading to the identification of several somatic alterations. Although familial NB is rare, linkage data obtained from different families have provided evidence of linkage to markers mapping to different chromosomal regions, indicating a remarkable genetic heterogeneity of NB.

Somatostatin receptor subtype-dependent regulation of nitric oxide release: involvement of different intracellular pathways.

We reported previously that, in addition to direct effects, somatostatin (SST) affects tumor growth inhibiting the tumoral neoangiogenesis, via an interference with NO synthesis. Here, we analyzed the effects of SST on nitric oxide (NO) production induced by different agonists [basic fibroblast growth factor (bFGF), insulin, cholecystokinin (CCK)] and the intracellular signaling involved, using Chinese hamster ovary-k1 cells stably transfected with individual SSTR1-SSTR4. bFGF and insulin induced endothelial nitric oxide synthase activity via the generation of ceramide or the Akt-dependent phosphorylation of endothelial nitric oxide synthase, respectively.

Structural characterization of the nonameric assembly of an Archaeal alpha-L-fucosidase by synchrotron small angle X-ray scattering.

alpha-l-Fucosidase is a lysosomal enzyme responsible for hydrolyzing the alpha-1,6-linked fucose joined to the reducing-end N-acetylglucosamine of carbohydrate moieties in glycoproteins. The first alpha-l-fucosidase from Archaea was recently identified in the genome of the hyperthermophile Sulfolobus solfataricus; the enzyme is encoded by two open reading frames separated by a -1 frameshift. A preliminary biochemical and biophysical characterization of this extremophile enzyme has been carried out both in solution, through small angle X-ray scattering experiments, and in the crystalline state, showing an unusual oligomeric assembly resulting from the association of nine subunits, endowed with 3-fold molecular symmetry.

IFN-gamma production in human NK cells through the engagement of CD8 by soluble or surface HLA class I molecules.

The engagement of CD8 on NK cell surface by either surface or soluble HLA class I (sHLA-I) molecules induces synthesis and secretion of IFN-gamma. HLA-I-mediated effects were inhibited by the covering of CD8 with specific anti-CD8 monoclonal antibodies, indicating a direct interaction of HLA-I and CD8. That CD8 ligation induces IFN-gamma production was further supported by the finding that cross-linking of CD8 led to release of IFN-gamma at similar levels to those obtained with HLA-I.

Pyrrolidinedithiocarbamate induces apoptosis in cerebellar granule cells: involvement of AP-1 and MAP kinases.

Pyrrolidinedithiocarbamate (PDTC) is a compound displaying antioxidant, pro-oxidant and metal chelator properties in different cell types. It has been described that PDTC may exert either anti-apoptotic or apoptotic activity. Moreover it is known that this agent regulates the activity of redox-sensitive transcription factors, such as AP-1 and NF-kappaB.

Proteasome inhibitors induce cerebellar granule cell death: inhibition of nuclear factor-kB activation.

Many activities of neuronal cells, such as synaptic transmission, inflammation, neuroprotection, and neurotoxicity, are regulated by the activity of the transcription factor nuclear factor-kappaB (NF-kappaB). In resting cells, NF-kappaB activity is present both in the cytoplasm, as an inducible-inactive complex, and in the nucleus as a constitutive form. The activation of its inducible form is related to processing of IkappaB(s), which occurs through the proteasome.

Nitric oxide production stimulated by the basic fibroblast growth factor requires the synthesis of ceramide.

Nitric oxide (NO) is an intracellular and intercellular mediator involved in the modulation of many physiologic and pathologic processes including the regulation of neoangiogenesis. We analyzed the effects of basic fibroblast growth factor (bFGF) on NO production in CHO-K1 cells and the intracellular mechanisms involved. bFGF induces NO production through activation of the endothelial NO synthase (eNOS), causing a subsequent increase in cGMP levels.

Soluble HLA class I induces NK cell apoptosis upon the engagement of killer-activating HLA class I receptors through FasL-Fas interaction.

The engagement of the activating isoforms of C-type lectin inhibitory receptor (CLIR) or killer Ig-like receptor (KIR) by their natural ligands, represented by soluble HLA-I (sHLA-I) molecules, induced programmed cell death of natural killer (NK) cells. Indeed, NK cell apoptosis elicited by either putative HLA-E and HLA-F (sHLA-I non-A, -B, -C, and -G) or sHLA-I-Cw4 or -Cw3 from untransfected or -Cw4 or -Cw3 alleles transfected HLA-A(-), B(-), C(-), G(-), E(+), F(+) 721.221 lymphoblastoid cell line, respectively, was blocked by covering the corresponding activating receptor with either anti-CLIR- or anti-KIR-specific monoclonal antibodies (mAbs).

Expression in E. coli and purification of recombinant fragments of wild type and mutant human prion protein.

Prion diseases are fatal neurodegenerative disorders of the CNS of men and animals, characterized by spongiform degeneration of the CNS, astrogliosis and deposition of amyloid into the brain. The conversion of a cellular glycoprotein (the prion protein, PrP(C)) into an altered isoform (the prion scrapie, PrP(Sc)), which accumulates within the brain tissue by virtue of its resistance to the intracellular catabolism, is currently believed to represent the etiologic agent responsible for these diseases. Synthetic or recombinant polypeptides are commonly used to elucidate the mechanism of proteins involved in neurodegenerative diseases.

p38 MAP kinase mediates the cell death induced by PrP106-126 in the SH-SY5Y neuroblastoma cells.

Prion diseases are neurodegenerative pathologies characterized by the accumulation in the brain of a protease-resistant form of the prion protein (PrP(c)), named PrP(Sc). A synthetic peptide homologous to residues 106-126 of PrP (PrP106-126) maintains many PrP(Sc) characteristics. We investigated the intracellular signaling responsible for the PrP106-126-dependent cell death of SH-SY5Y, a cell line derived from a human neuroblastoma.

Inhibition of nuclear factor-kappaB activation induces apoptosis in cerebellar granule cells.

The nuclear factor (NF)-kappaB family of transcription factors plays important roles in the regulation of many activities of neuronal cells, such as synaptic transmission, inflammation, neuroprotection, and neurotoxicity. In resting cells, NF-kappaB activity is present both in the cytoplasm, as an inducible-inactive complex, and in the nucleus, as a constitutive form. Regulation of its inducible activity relies on processing of IkappaB(s), which occurs through the proteasome.

Inhibition of angiogenesis-driven Kaposi's sarcoma tumor growth in nude mice by oral N-acetylcysteine.

The thiol N-acetyl-L-cysteine (NAC), an analogue and precursor of reduced glutathione, has cancer chemopreventive properties attributable to its nucleophilicity, antioxidant activity, and a variety of other mechanisms. We demonstrated recently that NAC has anti-invasive, antimetastatic, and antiangiogenic effects in in vitro and in vivo test systems. In the present study, s.

The activation of the phosphotyrosine phosphatase eta (r-PTP eta) is responsible for the somatostatin inhibition of PC Cl3 thyroid cell proliferation.

The aim of this study was the characterization of the intracellular effectors of the antiproliferative activity of somatostatin in PC Cl3 thyroid cells. Somatostatin inhibited PC Cl3 cell proliferation through the activation of a membrane phosphotyrosine phosphatase. Conversely, PC Cl3 cells stably expressing the v-mos oncogene (PC mos) were completely insensitive to the somatostatin antiproliferative effects since somatostatin was unable to stimulate a phosphotyrosine phosphatase activity.

Stromal cell-derived factor-1alpha induces astrocyte proliferation through the activation of extracellular signal-regulated kinases 1/2 pathway.

Stromal cell-derived factor-1 (SDF-1), the ligand of the CXCR4 receptor, is a chemokine involved in chemotaxis and brain development that also acts as co-receptor for HIV-1 infection. We previously demonstrated that CXCR4 and SDF-1alpha are expressed in cultured type-I cortical rat astrocytes, cortical neurones and cerebellar granule cells. Here, we investigated the possible functions of CXCR4 expressed in rat type-I cortical astrocytes and demonstrated that SDF-1alpha stimulated the proliferation of these cells in vitro.

Exclusion of candidate genes and chromosomal regions in familial neuroblastoma.

Two families with recurrence of neuroblastoma one Italian and one British with three and two affected children respectively were genotyped using polymorphic markers on chromosome 1 spanning the p32-p36 region frequently deleted in neuroblastoma tumor cells. Linkage to this region was excluded by haplotype inspection and negative lod scores. Furthermore, the exclusion of genes involved in neurocristopathies sometimes associated with neuroblastoma was carried out by typing the Italian family with polymorphic markers located in or near the corresponding genes.

Somatostatin receptor 1 (SSTR1)-mediated inhibition of cell proliferation correlates with the activation of the MAP kinase cascade: role of the phosphotyrosine phosphatase SHP-2.

The mitogen activated protein (MAP) kinase cascade represents one of the major regulator of cell growth by hormones and growth factors. However, although the activation of this intracellular pathway has been often regarded as mediator of cell proliferation, in many cell types the increase in MAP kinase (also called extra-cellular signal regulated kinase: ERK) activity may result in cell growth arrest, depending on the length or the intensity of the stimulation. In this review we examine recent data concerning the effects of somatostatin on the MAP kinase cascade through one of its major receptor subtype, the somatostatin receptor 1 (SSTR1), stably expressed in CHO-K1 cells.

Somatostatin and its analog lanreotide inhibit the proliferation of dispersed human non-functioning pituitary adenoma cells in vitro.

Objective: Somatostatin is a powerful inhibitor of hormone secretion and cell proliferation. Treatment with somatostatin analogs in humans causes a reduction in size and secretory activity of some endocrine tumors, including somatotropic pituitary adenomas. Less studied are the effects of somatostatin agonists on non-functioning pituitary adenomas (NFPAs).

Derivative chromosome 17 in a case of Burkitt lymphoma with 8;14 translocation.

A complex chromosome rearrangement present in a B-cell line established from a patient with Burkitt lymphoma was studied by using fluorescence in situ hybridization (FISH) and immunocytochemistry techniques. The rearranged chromosome (der17) was apparently composed of 17q, of a partially deleted 17p, and of other material of chromosome 17p origin that was interspersed with regions without any clear banding pattern. der(17) contained a functional ch17 centromere and two additional centromeres of unknown origin that were inactive by all evidence.