Differential expression of DNA-methyltransferases in drug resistant murine neuroblastoma cells.

Neuroblastoma tumors frequently become drug resistant during the process of chemotherapy resulting in unfavorable clinical outcomes. Development of sustained drug resistance in neuroblastoma is a major problem in successful treatment. To explore the role of DNA-methyltransferases (Dnmt) in acquired drug resistance of neuroblastoma, the present investigation was carried out to study the expression of Dnmtl, Dnmt3a, and Dnmt3b in drug resistant murine neuroblastoma cells, in an in vitro model system.

Cord-like mosaic patches in the adrenal cortex are fractal: implications for growth and development.

Organogenesis proceeds rapidly and faithfully during fetal development. The process includes generation of parenchyma, followed by organization into functional tissues. The method by which the growth of organ parenchyma is regulated is not known, but insight into this regulation has been obtained by studying mosaic tissues of experimental chimeras and transgenic mosaics.

Activating mutations of the lutropin choriogonadotropin receptor in precocious puberty.

The human receptor for lutropin and chorionic gonadotropin (LHR) is a member of the G-protein-coupled receptor superfamily and plays a key role in normal and abnormal reproductive physiology. Naturally occurring mutations of the LHR gene that lead to hormone-independent signaling are associated with abnormal Leydig cell growth and precocious puberty in boys. These mutations affect 13 different residues in the LHR, with the majority clustered in the cytoplasmic half of transmembrane helix 6.

Juvenile dermatomyositis: immunogenetics, pathophysiology, and disease expression.

Data are rapidly accumulating documenting disease susceptibility may be linked to genetic markers (DQA1*0501 or related alleles) which are associated with upregulation of IFN-alpha/beta inducible genes elicited in response to an antigen which may be viral. Continued immune-mediated inflammation, resulting in partial lipodystrophy and pathological calcifications, may be fanned by the increased production of TNF alpha usually associated with the TNF alpha-308A allele.

Different regulation of T-box genes Tbx4 and Tbx5 during limb development and limb regeneration.

The T-domain transcription factors Tbx4 and Tbx5 have been implicated, by virtue of their limb-type specific expression, in controlling the identity of vertebrate legs and arms, respectively. To study the roles of these genes in developing and regenerating limbs, we cloned Tbx4 and Tbx5 cDNAs from the newt, and generated antisera that recognize Tbx4 or Tbx5 proteins. We show here that, in two urodele amphibians, newts and axolotls, the regulation of Tbx4 and Tbx5 differs from higher vertebrates.

Functional conservation of HIV-1 Vpr and variability in a mother-child pair of long-term non-progressors.

Increasing evidence suggests that HIV-1 Vpr is required in vivo for viral pathogenesis. Since Vpr displays multiple activities, little is known about which Vpr-specific activities are conserved in naturally occurring viruses or how natural mutations in Vpr might modulate viral pathogenesis in HIV-infected individuals. The goals of this study were to evaluate the functional variability of Vpr in naturally occurring viruses.

A colorimetric bead-binding assay for detection of intermolecular interactions.

We have developed a new technique that rapidly and reproducibly allows direct visualization of molecular interactions, including receptor-ligand binding. The technique can be easily applied to examine binding between proteins and glycoproteins, or proteins and glycolipids, including gangliosides. In this novel bead-binding assay, the suspected 'ligand' molecule is bound to 0.

Ganglioside induces caveolin-1 redistribution and interaction with the epidermal growth factor receptor.

Although caveolin-1 is thought to facilitate the interaction of receptors and signaling components, its role in epidermal growth factor receptor (EGFR) signaling remains poorly understood. Ganglioside GM3 inhibits EGFR autophosphorylation and may thus affect the interaction of caveolin-1 and the EGFR. We report here that endogenous overexpression of GM3 leads to the clustering of GM3 on the cell membrane of the keratinocyte-derived SCC12 cell line and promotes co-immunoprecipitation of caveolin-1 and GM3 with the EGFR.

Engraftment assessment in human and mouse liver tissue after sex-mismatched liver cell transplantation by real-time quantitative PCR for Y chromosome sequences.

Transplanted hepatocytes can engraft, proliferate, and function permanently in host animals. After one cell infusion, however, engrafted hepatocytes constitute only between 1 in 200 to 1 in 3,000 host liver cells. Although transplanted cells can be identified using biochemical and molecular techniques, more accurate methods are needed to evaluate interventions that could improve cell engraftment rates.

Firearm-related death and injury among children and adolescents.

As the articles in this journal issue show, gun violence affects children and youth in many ways: psychologically, emotionally, financially, and legally. But first and foremost, gun violence affects children's physical safety. Therefore, this issue opens with an overview of the physical toll that firearms exact upon children and youth, reviewing the incidence of firearm-related injury and death among Americans under age 20.

Ganglioside modulation regulates epithelial cell adhesion and spreading via ganglioside-specific effects on signaling.

Gangliosides are implicated in regulating cell adhesion and migration on fibronectin by binding with the alpha(5) subunit of alpha(5)beta(1) integrin. However, the effects of gangliosides on cell spreading and related signaling pathways are unknown. Increases in gangliosides GT1b and GD3 inhibited spreading on fibronectin, concurrent with inhibition of Src and focal adhesion kinase.

Doxorubicin resistant neuroblastoma cells secrete factors that activate AKT and attenuate cytotoxicity in drug-sensitive cells.

The present study aims to verify the hypothesis that tumor cells with acquired resistance to chemotherapy may secrete survival factors and thus, participate in the protection of drug-sensitive cells against drug toxicity. A human neuroblastoma cell line, SK-N-SH, and its doxorubicin resistant derivative, RDOX6, have been used. Conditioned medium from RDOX6 cells attenuated the cytotoxic response of SK-N-SH cells to doxorubicin.

Increased plasma thrombospondin-1 (TSP-1) levels are associated with the TNF alpha-308A allele in children with juvenile dermatomyositis.

Vascular occlusion is more frequent in children with juvenile dermatomyositis (JDM) who have the TNF alpha-308A allele. One of the potent anti-angiogenic factors is thrombospondin-1 (TSP-1). This study investigated the association of the TNF alpha-308A allele with circulating levels of angiogenic mediators, TSP-1, and platelet factor 4 (PF4) using fresh, platelet-poor plasma (PPP).

Ganglioside loss promotes survival primarily by activating integrin-linked kinase/Akt without phosphoinositide 3-OH kinase signaling.

Keratinocyte gangliosides influence cellular functions, including proliferation, adhesion, migration, and differentiation. The effects of endogenous depletion of membrane gangliosides by gene transfection of a human ganglioside-specific sialidase on cell survival were investigated. Ganglioside depletion promotes survival of the human keratinocyte-derived SCC12 cell line through upregulated phosphorylation of beta1 integrin, and increased phosphorylation and activity of integrin-linked kinase, protein kinase B/Akt, and Bad, with resultant inhibition of caspase-9 activation.

Loss of cell anchorage triggers apoptosis (anoikis) in primary mouse hepatocytes.

Liver cell isolation and transplantation have been successfully performed in animal models and in humans. However, lack of initial engraftment due to cell death is a major roadblock to achieving clinical significance. Apoptosis was recently identified as an important cause of freshly isolated and banked hepatocyte cell death [Cell Transplant.

Cooperative E-box regulation of human GLI1 by TWIST and USF.

Sonic hedgehog signaling plays a critical role in vertebrate patterning, and signaling defects are associated with severe birth defects and cancer in man. GLI1 encodes a critical transcription activator in this pathway. GLI1 is expressed in human basal cell carcinomas and sarcomas.

Molecular characterization and mapping of ATOH7, a human atonal homolog with a predicted role in retinal ganglion cell development.

The human ATOH7 gene encodes a basic helix-loop-helix (bHLH) transcription factor that is highly similar to Drosophila Atonal within the conserved bHLH domain. The ATOH7 coding region is contained within a single exon. We mapped ATOH7 to Chromosome (Chr) 10q21.

Quantification of human immunodeficiency virus type 1 proviral DNA by using TaqMan technology.

A protocol for quantification of human immunodeficiency virus type 1 (HIV-1) proviral DNA with the TaqMan technology was developed and validated. The assay was specific for HIV-1, with an analytic sensitivity of 10 copies and a linear dynamic range of >6 logs. Viral RNA levels, when at a stable state, were highly correlated with proviral DNA levels in 80 specimens of 18 HIV-infected children.

HIV-1 VPR modulates cell cycle G2/M transition through an alternative cellular mechanism other than the classic mitotic checkpoints.

HIV-1 Vpr induces cell cycle G2/M arrest in both human and fission yeast cells, suggesting a highly conserved activity of this viral protein. In this review, we summarize the current understanding of Vpr-induced G2 arrest based on studies from both mammalian cells and the fission yeast (Schizosaccharomyces pombe) model system. Fission yeast has proven to be an excellent model system to investigate cell cycle G2/M control of eukaryotic cells.

Doxorubicin-induced apoptosis in caspase-8-deficient neuroblastoma cells is mediated through direct action on mitochondria.

Unlabelled: The induction of p53 expression and stimulation of the Fas/caspase-8 pathway represent major mechanisms by which cytotoxic drugs induce apoptosis, but in neuroblastomas, the caspase-8 gene is often not expressed.

Purpose: The aim of this study was to determine whether doxorubicin could induce apoptosis in caspase-8-deficient neuroblastoma cells and to define its mechanism of action.

Methods: The caspase-8-deficient human neuroblastoma cell line, SKN-SH, was incubated with doxorubicin and the apoptotic response, as well as expression of apoptotic molecules in the p53/ Fas/caspase-8 pathway, were determined.

Involvement of rhp23, a Schizosaccharomyces pombe homolog of the human HHR23A and Saccharomyces cerevisiae RAD23 nucleotide excision repair genes, in cell cycle control and protein ubiquitination.

A functional homolog (rhp23) of human HHR23A and Saccharomyces cerevisiae RAD23 was cloned from the fission yeast Schizosaccharomyces pombe and characterized. Consistent with the role of Rad23 homologs in nucleotide excision repair, rhp23 mutant cells are moderately sensitive to UV light but demonstrate wild-type resistance to gamma-rays and hydroxyurea. Expression of the rhp23, RAD23 or HHR23A cDNA restores UV resistance to the mutant, indicating that rhp23 is a functional homolog of the human and S.

Gene expression profiling leads to identification of GLI1-binding elements in target genes and a role for multiple downstream pathways in GLI1-induced cell transformation.

The zinc finger transcription factor GLI1, which mediates Sonic hedgehog signaling during development, is expressed in several human cancers, including basal cell carcinoma, medulloblastoma, and sarcomas. We identified 147 genes whose levels of expression were significantly altered in RNA obtained from cells demonstrating a transformed phenotype with stable GLI1 expression or stable Ha-ras expression. Comparison of expression profiles from GLI1- and Ha-ras-expressing cells established a set of genes unique to GLI1-induced cell transformation.