Search results for "Oncogene protein"
showing 10 items of 812 documents
Melatonin induces transcriptional regulation of Bim by FoxO3a in HepG2 cells
2012
Background: Melatonin induces apoptosis in many different cancer cell lines, including hepatocellular carcinoma cells. However, the responsible pathways have not been clearly elucidated. A member of the forkhead transcription factors' family, FoxO3a, has been implicated in the expression of the proapoptotic protein Bim (a Bcl-2-interacting mediator of cell death). In this study, we used human HepG2 liver cancer cells as an in vitro model to investigate whether melatonin treatment induces Bim through regulation by the transcription factor FoxO3a. Methods: Cytotoxicity of melatonin was compared in HepG2 hepatoblastoma cells and primary human hepatocytes. Proapoptotic Bim expression was analys…
A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal
2000
In the rat pineal gland cAMP mediates nocturnal induction of the enzyme arylalkylamine N-acetyltransferase (AA-NAT) as well as of transcription factors such as inducible cAMP early repressor (ICER), Fos-related antigen-2 (Fra-2) and JunB. Cyclic AMP stimulates the phosphorylation of the DNA binding protein cAMP response element binding protein (CREB). While cAMP-induced CREB phosphorylation appears to be a prerequisite for AA-NAT and ICER gene expression, it is not known whether CREB phosphorylation accounts for the full cAMP response of the two genes. Furthermore, the significance of CREB phosphorylation in cAMP-activated Fra-2 and JunB transcription is unknown. In the present in vitro stu…
Longitudinal analysis of Mycobacterium tuberculosis 19-kDa antigen-specific T cells in patients with pulmonary tuberculosis: association with disease…
2003
CD8(+) T cells play a central role in immune protection against infection with Mycobacterium tuberculosis. One of the target epitopes for anti-M. tuberculosis directed CD8(+) T cells is the HLA-A2-restricted 19-kDa lipoprotein peptide VLTDGNPPEV. T cell clones directed against this epitope recognized not only the nominal peptide ligand, but also a closely related peptide (VPTDPNPPEV) from the HIV envelope gp120 (HIV(env) gp120) protein characterized by IFN-gamma release. This cross-reactivity was confirmed in ex vivo in M. tuberculosis 19-kDa tetramer-sorted T cells from patients with tuberculosis and in HIVgp120 tetramer-reactive T cells sorted from HIV(+) patients. M. tuberculosis 19-kDa …
Recent advances on aptamer-based biosensors to detection of platelet-derived growth factor.
2018
Platelet-derived growth factor (PDGF-BB), a significant serum cytokine, is an important protein biomarker in diagnosis and recognition of cancer, which straightly rolled in proceeding of various cell transformations, including tumor growth and its development. Fibrosis, atherosclerosis are certain appalling diseases, which PDGF-BB is near to them. Generally, the expression amount of PDGF-BB increases in human life-threatening tumors serving as an indicator for tumor angiogenesis. Thus, identification and quantification of PDGF-BB in biomedical fields are particularly important. Affinity chromatography, immunohistochemical methods and enzyme-linked immunosorbent assay (ELISA), conventional m…
Analysis of p53 and mdm2 proteins in malignant fibrous histiocytoma in absence of gene alteration: prognostic significance.
2000
TP53 and MDM2 genes and their protein expression were evaluated in frozen and paraffin-embedded tissue from 27 patients with malignant fibrous histiocytoma to elucidate the relationship between them, their implication in tumor progression mechanisms and their possible diagnostic-prognostic value in malignant fibrous histiocytoma. Single-strand conformation polymorphism analysis and direct sequencing of polymerase chain reaction-amplified DNA were used to establish two TP53 mutations (7.4%): a point mutation and a 63-bp duplication. Amplification of the MDM2 gene was observed in two tumors (7.4%) by means of Southern-blot analysis, one of them also carrying the TP53 point mutation. Immunohis…
Analysis of the p53 and MDM-2 gene in acute myeloid leukemia
1996
The MDM-2 (murine double minute 2) gene codes for a cellular protein that can bind to the p53 tumor suppressor gene product, thereby functioning as a negative regulator of p53. In order to define the role of the MDM-2 gene in the pathogenesis of human acute myeloid leukemia, the expression and the sequence of the MDM-2 gene were examined in samples of bone marrow and/or peripheral mononuclear cells of 38 patients by using immunostaining, polymerase chain reaction (PCR), single strand conformation polymorphism, and sequencing. Immunohistochemical staining detected a weak accumulation of the MDM-2 protein in AML patients of FAB classification M4 and M5. RT-PCR analysis revealed a heterogeneou…
Direct Activation of Bax by p53 Mediates Mitochondrial Membrane Permeabilization and Apoptosis
2004
The tumor suppressor p53 exerts its anti-neoplastic activity primarily through the induction of apoptosis. We found that cytosolic localization of endogenous wild-type or trans-activation–deficient p53 was necessary and sufficient for apoptosis. p53 directly activated the proapoptotic Bcl-2protein Bax in the absence of other proteins to permeabilize mitochondria and engage the apoptotic program. p53 also released both proapoptotic multidomain proteins and BH3-only proteins [Proapoptotic Bcl-2family proteins that share only the third Bcl-2homology domain (BH3)] that were sequestered by Bcl-xL. The transcription-independent activation of Bax by p53 occurred with similar kinetics and concentra…
Human Papilloma Virus-Dependent HMGA1 Expression Is a Relevant Step in Cervical Carcinogenesis
2008
HMGA1 is a member of a small family of architectural transcription factors involved in the coordinate assembly of multiprotein complexes referred to as enhanceosomes. In addition to their role in cell proliferation, differentiation, and development, high-mobility group proteins of the A type (HMGA) family members behave as transforming protoncogenes either in vitro or in animal models. Recent reports indicated that HMGA1 might counteract p53 pathway and provided an interesting hint on the mechanisms determining HMGA's transforming potential. HMGA1 expression is deregulated in a very large array of human tumors, including cervical cancer, but very limited information is available on the mole…
Liver specific overexpression of platelet-derived growth factor-B accelerates liver cancer development in chemically induced liver carcinogenesis
2010
A genetic basis of hepatocellular carcinoma (HCC) has been well-established and major signaling pathways, such as p53, Wnt-signaling, transforming growth factor-β (TGF-β) and Ras pathways, have been identified to be essential to HCC development. Lately, the family of platelet-derived growth factors (PDGFs) has shifted to the center of interest. We have reported on spontaneously developing liver fibrosis in PDGF-B transgenic mice. Since HCC rarely occurs in healthy liver, but dramatically increases at the cirrhosis stage of which liver fibrosis is a preliminary stage, we investigated liver cancer development in chemically induced liver carcinogenesis in these mice. HCC induction was performe…
Human Fetal Aorta Contains Vascular Progenitor Cells Capable of Inducing Vasculogenesis, Angiogenesis, and Myogenesis in Vitro and in a Murine Model …
2007
Vasculogenesis, the formation of blood vessels in embryonic or fetal tissue mediated by immature vascular cells (ie, angioblasts), is poorly understood. We report the identification of a population of vascular progenitor cells (hVPCs) in the human fetal aorta composed of undifferentiated mesenchymal cells that coexpress endothelial and myogenic markers. Under culture conditions that promoted cell differentiation, hVPCs gave rise to a mixed population of mature endothelial and mural cells when progenitor cells were stimulated with vascular endothelial growth factor-A or platelet-derived growth factor-betabeta. hVPCs grew as nonadherent cells and, when embedded in a three-dimensional collagen…