Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1522282 (EMT)
 2,868 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The potential usefulness of substrates for glycolysis and nucleic acid synthesis as tumor imaging agents was compared to that of 67Ga-citrate. In separate experiments, 3H-thymidine, 3H-uridine, 14C-2-deoxyglucose, and 67Ga-citrate were injected intraveneously into BALB/c mice with solid subcutaneous EMT-6 sarcomas. For the 3H- and 14C-labeled substrates, absolute uptakes in tumor and tumor-to-blood ratios were as high 1 hour after injection as the comparable maximum values achieved for 67Ga-citrate after 48 hours. These studies suggest that positron-labeled analogues of thymidine, uridine, and 2-deoxyglucose should be useful radiopharmaceuticals for tumor imaging by positron-emission tomography.
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PMID:Positron imaging feasibility studies: selective tumor concentration of 3H-thymidine, 3H-uridine, and 14C-2-deoxyglucose. 696 45

Uridine phosphorylase (UPase) is a key enzyme in the pyrimidine salvage pathway. It reversibly catalyzes the catabolism of uridine to uracil; controls the homeostatic regulation of uridine concentration in plasma and tissues; and plays a role in the intracellular activation of 5-fluorouracil. We cloned the murine UPase gene promoter, a 1703-bp fragment, and determined the transcription initiation sites located at +1 and +92 bp of the cDNA sequence. Through transient expression analysis of the 5'-flanking region of UPase gene, we have evaluated the promoter activity for a series of fragments with 5'- to 3'-deletion in murine breast cancer EMT-6 cells and immortalized murine fibroblast NIH 3T3 cells. Cotransfection of the UPase promoter constructs (from -1619 to -445) containing p53 binding motif with the wild-type p53 construct resulted in a significant reduction of luciferase activity; however, this effect disappeared with the additional deletion of the -445 to -274 sequence to suggest the existence in this promoter region of a putative p53 recognition element. Similar cotransfection in murine embryo fibroblasts p53-/- confirmed the inhibitory role of p53 on the UPase promoter activity. The specificity of the interaction is demonstrated by nuclear protein-specific binding to the putative p53 recognition sequence using gel mobility shift assay and DNase I footprinting analysis. These data indicate the UPase gene is a novel target of p53, and its expression is down-regulated by p53 at the promoter level.
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PMID:p53-dependent suppression of uridine phosphorylase gene expression through direct promoter interaction. 1155 67