Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin 8 (IL-8) is a novel cytokine which possesses neutrophil chemotactic and activating activities in addition to chemotactic activity for basophils and T lymphocytes. It has been shown that IL-8 is produced by a variety of human somatic cells including monocytes/macrophages, dermal fibroblasts, vascular endothelial cells, keratinocytes, mesangeal cells, and several types of tumor cell lines. We have examined here whether or not human gastric cancer cell lines produce IL-8 in vitro. The production of IL-8 protein was detected by enzyme-linked immunosorbent assay in the culture supernatants derived from eight of nine human gastric cancer cell lines stimulated with either interleukin 1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF alpha), or TNF alpha plus interferon gamma (IFN gamma). In some of the gastric cancer cell lines such as MKN 45 and KATO, TNF alpha plus IFN gamma synergistically induced the production of IL-8. In MKN 45 cells, synergistic increase of the steady state level of IL-8 mRNA by TNF alpha plus IFN gamma was not inhibited by cycloheximide treatment. Scatchard analysis revealed that IFN gamma changed neither the number nor the affinity constant of TNF alpha binding sites on a gastric cancer cell line, suggesting that the synergism was a post-receptor event. Furthermore, synergistic induction of chloramphenicol acetyltransferase activity by TNF alpha plus IFN gamma was observed in MKN 45 that were transiently transfected with chimeric chloramphenicol acetyltransferase reporter genes driven by the transcriptional regulatory region of human IL-8 gene. Through the mutation of the regulatory region of the IL-8 gene, both AP-1- and NF-kB-like factor binding elements were presumed to be involved in conferring the responsiveness to TNF alpha plus IFN gamma. Moreover, gel retardation analyses revealed that TNF alpha and IFN gamma synergistically induced the binding of NF-kB like as well as AP-1 like proteins bound to these sites. These results indicated that IFN gamma synergistically enhanced TNF alpha-induced IL-8 production in a human gastric cancer cell line through synergistic activation of transcription factors without up-regulating TNF alpha receptor.
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PMID:Tumor necrosis factor alpha and interferon gamma synergistically induce interleukin 8 production in a human gastric cancer cell line through acting concurrently on AP-1 and NF-kB-like binding sites of the interleukin 8 gene. 133 Oct 59

We found that the expression of human platelet-activating factor receptor (PAFR) gene is differentially regulated by estrogen and TGF-beta 1. Primer extension analysis revealed that the levels of the PAFR transcript 2 were increased by estrogen, but decreased by TGF-beta 1 in the human stomach cancer cell line (JR-St cells) which expressed both functional endogenous PAFR transcript 1 (leukocyte-type) and transcript 2 (tissue-type). Both ligands did not affect the expression of intrinsic PAFR transcript 1. Furthermore, the response elements to estrogen and TGF-beta 1 in the PAFR promoter 2 were delineated by a transient expression assay using the chloramphenicol acetyltransferase (CAT) gene as a reporter in this cell line. A negative response element for TGF-beta 1 was mapped on the sequence from -90 bp to -81 bp, which has consensus sequence for TIE (TGF-beta 1 inhibitory element). Although consensus estrogen response element (AGGTCAnnnTGACCT) is not present in this promoter, the entire sequence comprising two AGGTCA half motifs spaced by 153 bp (from -257 bp to -93 bp) conferred weak but significant estrogen responsiveness. Thus, through these elements in the PAFR promoter 2, estrogen and TGF-beta 1 may regulate the PAFR gene to achieve a tissue-specific expression.
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PMID:Positive and negative regulations of human platelet-activating factor receptor transcript 2 (tissue-type) by estrogen and TGF-beta 1. 780 41

The human platelet-activating factor receptor (PAFR) gene is transcribed by two distinct promoters (promoter 1 and promoter 2) to generate two transcripts (designated as PAFR transcript 1 and PAFR transcript 2), though their open reading frames are identical. By primer extension analysis to discriminate two transcripts, we found that the levels of PAFR transcript 1 (leukocyte-type), but not PAFR transcript 2 (tissue-type), are upregulated by PAF as well as by 12-O-tetradecanoylphorbol-13-acetate (TPA) in the human stomach cancer cell line (JR-St cells) which expresses both functional PAFR transcript 1 and PAFR transcript 2 endogenously. Functional analysis of the promoter 1 with a transient expression assay using chloramphenicol acetyltransferase (CAT) gene as a reporter showed that both PAF and TPA activated the promoter 1 but not the deleted promoter lacking the three consensus binding sites for NF-kappa B located from -571 bp to -459 bp. These findings suggest a molecular mechanism of positive regulation of PAFR gene expression by PAF through NF-kappa B, possibly by a phosphorylation reaction involving protein kinase C by PAF.
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PMID:Platelet-activating factor (PAF) positively auto-regulates the expression of human PAF receptor transcript 1 (leukocyte-type) through NF-kappa B. 780 42