On the basis of these data, we conclude that a higher serum concentration of PFOA may cause liver enzymes to increase abnormally in the general population, particularly in obese individuals. Further studies are warranted to clarify the casual relationship between PFCs and these liver enzymes.
The c-myc proto-oncogene encodes a ubiquitous transcription factor involved in the control of cell growth and implicated in inducing tumorigenesis. Understanding the function of c-Myc and its role in cancer depends upon the identification of c-Myc target genes. Nijmegen breakage syndrome (NBS) is a chromosomal-instability syndrome associated with cancer predisposition, radiosensitivity, and chromosomal instability. The NBS gene product, NBS1 (p95 or nibrin), is a part of the hMre11 complex, a central player associated with double-strand break (DSB) repair. NBS1 contains domains characteristic for proteins involved in DNA repair, recombination, and replication. Here we show that c-Myc directly activates NBS1. c-Myc-mediated induction of NBS1 gene transcription occurs in different tissues, is independent of cell proliferation, and is mediated by a c-Myc binding site in the intron 1 region of NBS1 gene. Overexpression of NBS1 in Rat1a cells increased cell proliferation. These results indicate that NBS1 is a direct transcriptional target of c-Myc and links the function of c-Myc to the regulation of DNA DSB repair pathway operating during DNA replication.The c-myc proto-oncogene codes for a nuclear phosphoprotein ubiquitously expressed in somatic cells (1,2). Alterations of the c-myc locus, caused by chromosomal translocation, amplification, retroviral insertion, or retroviral transduction, deregulate c-Myc expression and contribute to tumorigenesis in different species (1,(3)(4)(5). The c-Myc protein contains a carboxyl-terminal basic, helix-loop-helix and leucine-zipper domain, which associates with another basic, helix-loop-helix and leucine-zipper protein (MAX) 1 as heterodimers, and an amino-terminal domain necessary for transcriptional transactivation (2, 6, 7). The heterodimeric complexes c-Myc⅐MAX are capable of binding DNA at a specific site (E-box) and activate transcription of downstream target genes by recruiting protein complexes that can regulate histone acetylation and modify chromatin structure (8 -10).The precise function of the c-Myc protein, and in particular the mechanism by which it promotes cell proliferation in normal and neoplastic cells, is not known. Using a variety of approaches, including genome-wide gene expression profiling, various c-Myc target genes have been identified and have been shown to be involved in heterogeneous functions, including cell cycle control, DNA synthesis, iron metabolism, protein synthesis, apoptosis, cell adhesion, and telomere maintenance (11). In Drosophila as well as in mammalian cells, c-Myc has been shown to promote cell growth (12, 13), although it has been recently reported that c-Myc may control organ and body size by regulating cell cycle entrance and cell number rather than cell size (14). A better understanding of the precise role of c-Myc depends upon the identification of the genes that are directly targeted by its transcriptional regulation.Nijmegen breakage syndrome (NBS) is an autosomal recessive hereditary disorder characterized by microcephaly,...
We delineated the longitudinal auditory features of the highly prevalent GJB2 p.V37I mutation on a general population basis and confirmed the utility of newborn genetic screening in identifying infants with late-onset or progressive hearing impairment undetectable by newborn hearing screening.Genet Med 19 1, 6-12.
Mesothelin, a secreted protein, is overexpressed in some cancers, but its exact function remains unclear. The aim of the present study was to evaluate the possible function of mesothelin. Real-time PCR, RT (reverse transcription)-PCR, cytotoxicity assays, proliferative assays, apoptotic assays by Hoechst staining, detection of active caspases 3 and 7 by flow cytometric analysis, and immunoprecipitation and immunoblotting were performed. Cancer tissues in paclitaxel-resistant ovarian cancer patients expressed higher levels of mesothelin as assessed using real-time PCR than paclitaxel-sensitive ovarian cancer patients (the mean crossing point value change of mesothelin was 26.9+/-0.4 in the resistant group and 34.3+/-0.7 for the sensitive group; P<0.001). Mesothelin also protected cells from paclitaxel-induced apoptosis. The protein expression of Bcl-2 family members, such as Bcl-2 and Mcl-1, was significantly increased regardless of whether cells were treated with exogenous mesothelin or were mesothelin-transfectants. Furthermore, mesothelin-treated cells revealed rapid tyrosine phosphorylation of the p85 subunit of PI3K (phosphoinositide 3-kinase) and ERK (extracellular-signal-regulated kinase) 1/2 for enhancing MAPK (mitogen-activated protein kinase) activity. The anti-apoptotic ability was suppressed and the expression of Bcl-2 family in response to mesothelin was altered by inhibiting PI3K activity, but not by inhibiting MAPK activity. Thus mesothelin can inhibit paclitaxel-induced cell death mainly by involving PI3K signalling in the regulation of Bcl-2 family expression. Mesothelin is a potential target in reducing resistance to cytotoxic drugs.
These findings support a critical protective role of sFlt-1 in endotoxic shock and sepsis. sFlt-1 may therefore have utility as an adjunctive agent for the treatment of sepsis syndrome.
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