Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0001430 (adenoma)
 21,222 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An increase in DNA synthesis runs parallel with an increase in the activity of cytoplasmic thymidine kinase (TK), an enzyme that catalyses the phosphorylation of deoxythymidine via the pyrimidine salvage pathway. In this work, I measured TK and its isozyme activities in normal thyroid tissue, Basedow's disease, adenomatous goiter, adenoma and adenocarcinoma of human thyroid glands. TK activity was assayed by the method of Taylor et al. The average TK activities in Basedow's disease, adenomatous goiter, adenoma and adenocarcinoma were 1.78, 1.75, 2.98 and 3.33 times than that in normal thyroid tissue, respectively. TK isozymes were separated by DEAE cellulose (DE-52, Whatman, Kent, UK) column chromatography (1.5 X 5.0 cm). The activities eluted at NaCl concentrations of 0M, 0.1M and 0. 2 M were named peak A,B and C, respectively. The average activities in peaks A and C were not significantly different from each other in these diseases. But the average activity of peak B in the thyroid adenocarcinoma was significantly higher (2.3 fold) than that in normal thyroid tissue. As the activity of this isozyme was not affected by deoxycytidine triphosphate (dCTP), it may be involved in DNA replication closely.
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PMID:[Thymidine kinase and its isozyme activities in human thyroid diseases]. 318 76

Reactive oxygen species from endogenous and environmental sources induce oxidative damage to DNA, and hence pose an enormous threat to the genetic integrity of cells. Such oxidative DNA damage is restored by the base excision repair (BER) pathway that is conserved from bacteria to humans and is initiated by DNA glycosylases, which simply remove the aberrant base from the DNA backbone by hydrolyzing the N-glycosidic bond (monofunctional DNA glycosylase), or further catalyze the incision of a resulting abasic site (bifunctional DNA glycosylase). In human cells, oxidative pyrimidine lesions are generally removed by hNTH1, hNEIL1, or hNEIL2, whereas oxidative purine lesions are removed by hOGG1. hSMUG1 excises a subset of oxidative base damage that is poorly recognized by the above enzymes. Unlike these enzymes, hMYH removes intact A misincorporated opposite template 8-oxoguanine during DNA replication. Although hNTH1, hOGG1, and hMYH account for major cellular glycosylase activity for inherent substrate lesions, mouse models deficient in the enzymes exhibit no overt phenotypes such as the development of cancer, implying backup mechanisms. Contrary to the mouse model, hMYH mutations have been shown to lead to a multiple colorectal adenoma syndrome and high colorectal cancer risk. For cleavage of the N-glycosidic bond, bifunctional DNA glycosylases (hNTH1, hNEIL1, hNEIL2, and hOGG1) use Lys or Pro for direct attack on sugar C1', whereas monofunctional DNA glycosylases (hSMUG1 and hMYH) use an activated water molecule. DNA glycosylases for oxidative damage, if not all, are covalently trapped by DNA containing 2-deoxyribonolactone or oxanine. Thus, the depletion of functional DNA glycosylases using covalent trapping may reduce the BER capacity of cancer cells, hence potentiating the efficacy of anticancer drugs or radiation therapy.
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PMID:Human DNA glycosylases involved in the repair of oxidatively damaged DNA. 1505 51

4-(3-pentylamino)-2,7-dimethyl-8-(2-methyl-4-methoxyphenyl)-pyrazolo-[1,5-a]-pyrimidine (DMP 904) is a potent and selective antagonist of corticotropin releasing factor receptor-1 (CRF1 receptor) with an efficacious anxiolytic profile in preclinical animal models. In subchronic toxicity studies in Sprague-Dawley rats, DMP 904 produced thyroid follicular cell hypertrophy and hyperplasia, and a low incidence of follicular cell adenoma. The current investigations were designed to determine the mode of action by which DMP 904 disrupts thyroid homeostasis in male rats. Five-day treatment with DMP 904 (300 mg/kg/day) dramatically lowered serum thyroxine (T4) to levels below detectable limits (< 1 microg/dl) by 72 h, with concurrent decreases in triiodothyronine (T3, about a 70% decrease) and increases in thyroid stimulating hormone (TSH; about a three-fold increase). DMP 904 increased [125I]T4 total body clearance (Cl tb) (38.21 +/- 10.45 ml/h) compared to control (5.61 +/- 0.59 ml/h) and phenobarbital-treated rats (7.92 +/- 1.62 ml/h). This increase in Cl(tb) was associated with a significant increase in biliary clearance (Cl bile) of unconjugated [125I]T4 (nearly 80-times control rates) and increased liver:blood ratios of T4, suggestive of enhanced hepatic uptake of T4. A single dose of DMP 904 (200 mg/kg) increased mRNA levels of hepatic cytochrome P450s (CYP 3A1 and CYP 2B1) and UDP-glucuronosyltransferases (UGT 1A1 and UGT 1A2). DMP 904 also induced mRNAs of the canalicular transporter, multi-drug resistance protein-2 (Mrp2) and sinusoidal transporters, organic anion transporting proteins (Oatp1 and Oatp2) within 24 h. Western blot analysis confirmed DMP 904 related increases in Oatp2 protein expression. Collectively, these data suggest that DMP 904 is an agonist of the constitutive androstane receptor (CAR) and pregnane X receptor (PXR) and that the decreased serum levels of T4 and T3 resulted from increased hepatobiliary clearance. However, DMP 904 is distinguished from other compounds associated with similar effects on thyroid hormone homeostasis because its effects were primarily related to increased biliary excretion of unconjugated T4.
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PMID:Increased hepatobiliary clearance of unconjugated thyroxine determines DMP 904-induced alterations in thyroid hormone homeostasis in rats. 1567 46

Folate is a B vitamin required for one-carbon transfer reactions including methylation of cell macromolecules including DNA and synthesis of the purines adenosine and guanosine and the pyrimidine thymidine. Epidemiological evidence suggests that diets providing higher amounts of folates lower the risk of colo-rectal cancer (CRC) and these observations are supported by plausible biological mechanisms. Inadequate folate supply results in DNA damage through (a) the incorporation of uracil (in place of thymidine) into DNA and subsequent unsuccessful attempts at DNA repair and (b) aberrant patterns of DNA methylation. However, human intervention studies using relatively large doses (500-5,000 mug/day) of folic acid (a synthetic form of folate) have provided no evidence of benefit in terms of adenoma recurrence. Indeed, there is some evidence of potential harm in increased risk of prostate cancer. Possible reasons for the apparent divergence in findings from the observational and intervention studies include the use of (unphysiologically) large doses of folic acid in the intervention studies whereas smaller intakes of food folates appeared to offer "protection" against CRC in case-control and prospective cohort studies. With intakes of folic acid greater than 400 mug/day, unmetabolised folic acid appears in peripheral blood and there are suggestions that this folic acid may have adverse effects e.g. reduced cytotoxicity of Natural Killer cells. Until the benefit-risk relationship associated with mandatory fortification with folic acid has been clarified (and, in particular, the possible risk of inducing extra cases of bowel or other cancer), it would seem wise to delay further mandatory folic acid fortification.
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PMID:Folate intake and bowel cancer risk. 1949 62

Cancer cells alter their metabolism for the production of precursors of macromolecules. However, the control mechanisms underlying this reprogramming are poorly understood. Here we show that metabolic reprogramming of colorectal cancer is caused chiefly by aberrant MYC expression. Multiomics-based analyses of paired normal and tumor tissues from 275 patients with colorectal cancer revealed that metabolic alterations occur at the adenoma stage of carcinogenesis, in a manner not associated with specific gene mutations involved in colorectal carcinogenesis. MYC expression induced at least 215 metabolic reactions by changing the expression levels of 121 metabolic genes and 39 transporter genes. Further, MYC negatively regulated the expression of genes involved in mitochondrial biogenesis and maintenance but positively regulated genes involved in DNA and histone methylation. Knockdown of MYC in colorectal cancer cells reset the altered metabolism and suppressed cell growth. Moreover, inhibition of MYC target pyrimidine synthesis genes such as CAD, UMPS, and CTPS blocked cell growth, and thus are potential targets for colorectal cancer therapy.
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PMID:Global metabolic reprogramming of colorectal cancer occurs at adenoma stage and is induced by MYC. 2884 64

Parathyroid adenoma is the main cause of primary hyperparathyroidism, which is characterized by enlarged parathyroid glands and excessive parathyroid hormone secretion. Here, we performed transcriptome analysis, comparing parathyroid adenomas with normal parathyroid gland tissue. RNA extracted from ten parathyroid adenoma and five normal parathyroid samples was sequenced, and differentially expressed genes (DEGs) were identified using strict cut-off criteria. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using DEGs as the input, and protein-protein interaction (PPI) networks were constructed using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) and visualized in Cytoscape. Among DEGs identified in parathyroid adenomas (n = 247; 45 up-regulated, 202 down-regulated), the top five GO terms for up-regulated genes were nucleoplasm, nucleus, transcription DNA-template, regulation of mRNA processing, and nucleic acid binding, while those for down-regulated genes were extracellular exosome, membrane endoplasmic reticulum (ER), membrane, ER, and melanosome. KEGG enrichment analysis revealed significant enrichment of five pathways: protein processing in ER, protein export, RNA transport, glycosylphosphatidylinositol-anchor biosynthesis, and pyrimidine metabolism. Further, PPI network analysis identified a densely connected sub-module, comprising eight hub molecules: SPCS2, RPL23, RPL26, RPN1, SEC11C, SEC11A, RPS25, and SEC61G. These findings may be helpful in further analysis of the mechanisms underlying parathyroid adenoma development.
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PMID:Comparative Gene Expression Profiles in Parathyroid Adenoma and Normal Parathyroid Tissue. 3083 48

Although substantial evidence supports aspirin's efficacy in colorectal cancer chemoprevention, key molecular mechanisms are uncertain. An untargeted metabolomics approach with high-resolution mass spectrometry was used to elucidate metabolic effects of aspirin treatment in human colon tissue. We measured 10,269 metabolic features in normal mucosal biopsies collected at colonoscopy after approximately 3 years of randomized treatment with placebo, 81 or 325 mg/day aspirin from 325 participants in the Aspirin/Folate Polyp Prevention Study. Linear regression was used to identify aspirin-associated metabolic features and network analysis was used to identify pathways and predict metabolite identities. Poisson regression was used to examine metabolic features associations with colorectal adenoma risk. We detected 471 aspirin-associated metabolic features. Aside from the carnitine shuttle, aspirin-associated metabolic pathways were largely distinct for 81 mg aspirin (e.g., pyrimidine metabolism) and 325 mg (e.g., arachidonic acid metabolism). Among aspirin-associated metabolic features, we discovered three that were associated with adenoma risk and could contribute to the chemopreventive effect of aspirin treatment, and which have also previously been associated with colorectal cancer: creatinine, glycerol 3-phosphate, and linoleate. The last two of these are in the glycerophospholipid metabolism pathway, which was associated with 81 mg aspirin treatment and provides precursors for the synthesis of eicosanoids from arachidonic acid upstream of cyclooxygenase inhibition by aspirin. Conversely, carnitine shuttle metabolites were increased with aspirin treatment and associated with increased adenoma risk. Thus, our untargeted metabolomics approach has identified novel metabolites and pathways that may underlie the effects of aspirin during early colorectal carcinogenesis.
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PMID:Metabolomics Analysis of Aspirin's Effects in Human Colon Tissue and Associations with Adenoma Risk. 3265 7