Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatostatin (SRIH) analogs can suppress the proliferation of human differentiated thyroid carcinoma cell lines that express SRIH receptors (SSTRs) demonstrated by radioligand binding analysis. Five distinct human SSTR subtypes (hSSTR1-5) that bind native SRIH exhibit diverse affinities to a wide range of SRIH analogs. Reverse transcriptase-PCR amplification of ribonucleic acids (RNAs) obtained from normal thyroid tissues and nine human thyroid carcinoma cell lines, grown as monolayer cultures and xenograft tumors in nude mice, were used to discriminate expression of SSTR subtype messenger RNAs (mRNAs). The cell lines were derived from a follicular adenoma (KAK-1), two follicular carcinomas (MRO-87 and WRO-82), two papillary carcinomas (NPA87 and KAT-10), and four anaplastic thyroid carcinomas (DRO-90, ARO-81, KAT-4, and KAT-18). Most thyroid cancer cell line monolayers and xenografts expressed SSTR3 and SSTR5 mRNAs. SSTR1 expression was more varied between monolayers and xenografts, whereas SSTR2 mRNA was only faintly detectable at the most extreme resolution. SSTR4 mRNA was faintly positive in only one anaplastic carcinoma xenograft. Normal thyroid also expressed SSTR3 and SSTR5 mRNAs, with only faint expression of SSTR1 and SSTR2 mRNAs (in one of five and three of five samples, respectively). SSTR mRNA expression was dependent upon in vitro culture conditions, as xenograft SSTR mRNA expression tended to decrease compared to that in each respective monolayer culture. Characterization of SSTR subtype expression in human thyroid carcinomas may permit targeting of specific SRIH analogs to inhibit proliferation of differentiated and anaplastic thyroid carcinomas in patients.
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PMID:Somatostatin receptor subtype expression in human thyroid and thyroid carcinoma cell lines. 917 96

Elucidation of the regulation of human sodium-iodide symporter (hNIS) gene expression is critical to understanding its effects on iodide concentration abilities of thyroid and thyroid carcinomas. To explore this issue, a 1.2-kb portion of the 5'-flanking region of the hNIS gene was isolated and characterized. Transient transfections with chimeric luciferase-reporter constructs into a differentiated human thyroid cell line, KAT-50, as well as non-thyroidal cells, defined an active promoter with tissue-specificity. Reverse-transcriptase polymerase chain reaction analysis for hNIS mRNA expression in normal human tissues was positive in thyroid, salivary gland, omentum, and gallbladder. KAT-50 cells expressed hNIS mRNA and were capable of thyrotropin-responsive iodide uptake in vitro. Despite the failure to exhibit iodide concentration in clinical anaplastic carcinoma tumors, 4 of 5 cell lines from this cancer phenotype expressed hNIS mRNA. Definition of the active promoter provides further insights and tools to uncover new approaches to use of radioiodine for therapy of thyroid carcinomas.
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PMID:Cloning of the human sodium-iodide symporter promoter and characterization in a differentiated human thyroid cell line, KAT-50. 949 56

Numerous invertebrate species belonging to several phyla cannot synthesize sterols de novo and rely on a dietary source of the compound. SCPx (sterol carrier protein 2/3-oxoacyl-CoA thiolase) is a protein involved in the trafficking of sterols and oxidation of branched-chain fatty acids. We have isolated SCPx protein from Spodoptera littoralis (cotton leafworm) and have subjected it to limited amino acid sequencing. A reverse-transcriptase PCR-based approach has been used to clone the cDNA (1.9 kb), which encodes a 57 kDa protein. Northern blotting detected two mRNA transcripts, one of 1.9 kb, encoding SCPx, and one of 0.95 kb, presumably encoding SCP2 (sterol carrier protein 2). The former mRNA was highly expressed in midgut and Malpighian tubules during the last larval instar. Furthermore, constitutive expression of the gene was detected in the prothoracic glands, which are the main tissue producing the insect moulting hormone. There was no significant change in the 1.9 kb mRNA in midgut throughout development, but slightly higher expression in the early stages. Conceptual translation of the cDNA and a database search revealed that the gene includes the SCP2 sequence and a putative peroxisomal targeting signal in the C-terminal region. Also a cysteine residue at the putative active site for the 3-oxoacyl-CoA thiolase is conserved. Southern blotting showed that SCPx is likely to be encoded by a single-copy gene. The mRNA expression pattern and the gene structure suggest that SCPx from S. littoralis (a lepidopteran) is evolutionarily closer to that of mammals than to that of dipterans.
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PMID:Characterization of a sterol carrier protein 2/3-oxoacyl-CoA thiolase from the cotton leafworm (Spodoptera littoralis): a lepidopteran mechanism closer to that in mammals than that in dipterans. 1514 83