Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.5.4.4 (adenosine deaminase)
5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The adenosine deaminase, 5'-nucleotidase, AMP-aminohydrolase and adenylate kinase activities and thymostimulin influence on these indices in vivo were studied in rat thymus and spleen lymphocytes in the latent period of DMBA-induced mammary carcinogenesis. The adenosine deaminase activity was established to increase while 5'-nucleotidase and AMF-aminohydrolase activity to decrease in the thymocytes of intact animals treated with thymostimulin; the adenylae kinase activity of spleen lymphocytes decreased as compared with that in the rats not treated with the preparation. The dynamics of changes in the investigated enzymes in activities in lymphocytes was of wave-like pattern in the latent period. The treatment of animals with thymostimulin in this period normalized adenosine deaminase activity and decreased the activity of the other enzymes in these cells.
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PMID:[Influence of thymostimulin on the activity of certain enzymes of adenosine and AMP metabolism in lymphocytes of rats with mammary cancer]. 628 53

Studies were undertaken on the activity of adenosine deaminase (ADA) and metabolic enzymes of AMP in the spleen and thymus cells of rats with DMBA-induced carcinogenesis of the mammary glands and on the effect of thymostimulin (TS) on this activity. In addition, we investigated the activity of ADA in the peripheral blood lymphocytes of the patients with premalignant diseases and cancer of the mammary glands (Stages I-IV) as well as the possibility of its enhancement by TS. The disturbances of these enzyme activities characterized by a decrease in ADA activity and an increase in activity of the AMP metabolism enzymes, predisposed for adenosine accumulation in lymphoid cells. Injection of TS normalized the ADA activity and decreased the activity of the AMP metabolic enzymes. Analogous results were obtained in the studies of ADA activity in the human materials. With the human tumor growth the in vitro effect of TS on the lymphocyte ADA activity decreased. We may suggest that measurement of the ADA activity in the lymphocytes may serve as a reliable tool to control the state of immune system and the effectiveness of immunotherapy with the thymic humoral factors.
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PMID:The lymphocyte activity of adenosine deaminase and enzymes of AMP metabolism in mammary carcinogenesis: the effect of thymostimulin. 632 26

Hyperthermia specifically inhibits the repair of UV-induced DNA photolesions in transcriptionally active genes. To define more precisely which mechanisms underlie the heat-induced inhibition of repair of active genes, removal of cyclobutane pyrimidine dimers (CPDs) was studied in human fibroblasts with different repair capacities and different transcriptional status of the adenosine deaminase gene, i.e. normal human cells, human cells carrying an inactive copy of the adenosine deaminase gene and xeroderma pigmentosum complementation group C fibroblasts. The results indicate that repair of active genes is impaired by inhibition of two repair pathways: (i) a global repair system involved in the repair of CPDs in potentially active genes; and (ii) the transcription-coupled repair pathway responsible for the accelerated repair of the transcribed strand. Since X-ray-induced DNA damage is also preferentially removed from the transcribed strand of active genes, selective inhibition of repair of radiation-induced DNA damage in active genes may play a key role in radiosensitization due to hyperthermia.
Carcinogenesis 1995 Apr
PMID:Selective inhibition of repair of active genes by hyperthermia is due to inhibition of global and transcription coupled repair pathways. 753 81

The epidermal differentiation complex (EDC) comprises a large number of genes that are of crucial importance for the maturation of the human epidermis. So far, 27 genes of 3 related families encoding structural as well as regulatory proteins have been mapped within a 2-Mb region on chromosome 1q21. Here we report on the identification of 10 additional EDC genes by a powerful subtractive hybridization method using entire YACs (950_e_2 and 986_e_10) to screen a gridded human keratinocyte cDNA library. Localization of the detected cDNA clones has been established on a long-range restriction map covering more than 5 Mb of this genomic region. The genes encode cytoskeletal tropomyosin TM30nm (TPM3), HS1-binding protein Hax-1 (HAX1), RNA-specific adenosine deaminase (ADAR1), the 34/67-kD laminin receptor (LAMRL6), and the 26S proteasome subunit p31 (PSMD8L), as well as five hitherto uncharacterized proteins (NICE-1, NICE-2, NICE-3, NICE-4, and NICE-5). The nucleotide sequences and putative ORFs of the EDC genes identified here revealed no homology with any of the established EDC gene families. Whereas database searches revealed that NICE-3, NICE-4, and NICE-5 were expressed in many tissues, no EST or gene-specific sequence was found for NICE-2. Expression of NICE-1 was up-regulated in differentiated keratinocytes, pointing to its relevance for the terminal differentiation of the epidermis. The newly identified EDC genes are likely to provide further insights into epidermal differentiation and they are potential candidates to be involved in skin diseases and carcinogenesis that are associated with this region of chromosome 1. Moreover, the extended integrated map of the EDC, including the polymorphic sequence tag site (STS) markers D1S1664, D1S2346, and D1S305, will serve as a valuable tool for linkage analyses.
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PMID:Identification of human epidermal differentiation complex (EDC)-encoded genes by subtractive hybridization of entire YACs to a gridded keratinocyte cDNA library. 1123 Jan 59

The recent discoveries of the RNA-mediated interference system in cells could explain all of the known features of human carcinogenesis. A key, novel idea, proposed here, is that the cell has the ability to recognise a mutated protein and/or mRNA. Secondly, the cell can generate its own short interfering RNA (siRNA) using an RNA polymerase to destroy mutated mRNA, even when only a single base pair in the gene has mutated. The anti-sense strand of the short RNA molecule (called sicRNA), targets the mutated mRNA of an oncogene or a tumour suppressor. The resulting double stranded RNA, using the RNA-induced silencing complex in the cytoplasm dices the mutated mRNA. In cancer-prone tissues, during cell mitosis, the sicRNA complex can move into the nucleus to target the mutated gene. The sicRNA, possibly edited by dsRNA-specific adenosine deaminase, converting adenosines to inosines, can be retained in the nucleus, with enhanced destructive capability. The sicRNA triggers the assembly of protein complexes leading to epigenetic modification of the promoter site of the mutant gene, specifically methylation of cytosines. In some instances, instead of methylation, the homologous DNA is degraded, leading to loss of heterozygosity. The factors controlling these two actions are unknown but the result is gene silencing or physical destruction of the mutant gene. The cell survives dependent on the functioning of the single, wild-type allele. An error in RNAi defence occurs when the sicRNA enters the nucleus and targets the sense strand of the wrong DNA. The sicRNA, because of the similarity of its short sequence and relaxed stringency, can target other RNAs, which are being transcribed. This can result in the methylation of the wrong promoter site of a gene or LOH of that region. In the vast majority of these cases, the aberrant hybridisations will have no effect on cell function or apoptosis eliminates non-viable cells. On a rare occasion, a preneoplastic cell is initiated when aberrant hybridisations switches on/off a gene involved in apoptosis, as well as a gene involved in cell proliferation and DNA damage surveillance. Genetic instability results when the sicRNA competes for a repeat sequence in the centromere or telomere, leading to gross chromosomal rearrangements. A malignancy develops when the sicRNAs fortuitously targets a microRNA (miRNA) or activates a transcription factor, resulting in the translation of a large number of new genes, alien to that tissue. This leads to dedifferentiation of the tissue, a resculpting of the histone code, chromosomal rearrangements, along a number of specific pathways, the gain of immortality and the dissemination of a metastatic cancer.
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PMID:The dialectics of cancer: A theory of the initiation and development of cancer through errors in RNAi. 1635 27

Excess of intracellular reactive oxygen species results in an environment that may modulate gene expression, or damage cellular molecules. These events are assumed to contribute to the process of carcinogenesis. In the present study, we measured the extent of lipid peroxidation and antioxidative status in colonic tumors and normal colonic mucosa obtained from 25 patients with colorectal carcinoma. Levels of lipid peroxides (PD) and of thiobarbituric acid reactive substances (TBARS) were significantly increased, by 54 and 59%, respectively, in tissue specimens obtained from the colonic tumor as compared with normal colonic mucosa (PD, 2.78+/-0.31 versus 1.81+/-0.29 nmol/mg tissue, TBARS, 0.86+/-0.1 versus 0.54+/-0.08 nmol/mg tissue). Activities of the antioxidant enzymes catalase and glutathione peroxidase (GPx) were also higher (by 67 and 29%, respectively) than in normal mucosa, probably in response to the increased free radical stress occurring in cancerous tissues. Myeloperoxidase (MPO) and adenosine deaminase (ADA) are markers of activated leukocytes and are related to the production of oxygen free radicals by these cells. Their activities were significantly elevated in the neoplastic tissue as compared to the normal tissue (MPO, 7.4+/-1.5 versus 4.1+/-0.95 U/mg tissue, ADA, 4.17+/-0.65 versus 2.99+/-0.80 U/g tissue), suggesting a possible involvement of activated leukocytes in the enhanced oxidative stress in the cancerous tissue. Our results demonstrate an enhanced oxidative stress in the neoplastic tissue. Leukocyte activation was also higher in the carcinogenic tissue, indicating a possible contribution of these cells to a further oxidative stress-derived tissue injury. These observations add to previous studies and may encourage therapeutic trials with antioxidants as a means of preventing colorectal cancer and preventing further tissue injury in the neoplastic tissue and its surroundings.
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PMID:Enhanced oxidative stress and leucocyte activation in neoplastic tissues of the colon. 1719 21

Berries contain a number of compounds that are proposed to have anticarcinogenic properties. We studied the effects and molecular mechanisms of wild berries with different phenolic profiles on intestinal tumorigenesis in multiple intestinal neoplasia/+ mice. The mice were fed a high-fat AIN93-G diet (Con) or AIN93-G diets containing 10% (w:w) freeze-dried bilberry, lingonberry (LB), or cloudberry (CB) for 10 wk. All 3 berries significantly inhibited the formation of intestinal adenomas as indicated by a 15-30% reduction in tumor number (P < 0.05). CB and LB also reduced tumor burden by over 60% (P < 0.05). Compared to Con, CB and LB resulted in a larger (P < 0.05) proportion of small adenomas (43, 69, and 64%, respectively) and a smaller proportion of large adenomas (56, 29, and 33%, respectively). Beta-catenin and cyclin D1 in the small and large adenomas and in the normal-appearing mucosa were measured by Western blotting and immunohistochemistry. CB resulted in decreased levels of nuclear beta-catenin and cyclin D1 and LB in the level of cyclin D1 in the large adenomas (P < 0.05). Early changes in gene expression in the normal-appearing mucosa were analyzed by Affymetrix microarrays, which revealed changes in genes implicated in colon carcinogenesis, including the decreased expression of the adenosine deaminase, ecto-5'-nucleotidase, and prostaglandin E2 receptor subtype EP4. Our results indicate that berries are potentially a rich source of chemopreventive components.
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PMID:Three Nordic berries inhibit intestinal tumorigenesis in multiple intestinal neoplasia/+ mice by modulating beta-catenin signaling in the tumor and transcription in the mucosa. 1788 12

Chemoprevention has emerged as a very effective preventive measure against carcinogenesis. Several bioactive compounds present in fruits and vegetables have revealed their cancer curative potential on benzo(a)pyrene (B(a)P) induced carcinogenesis. In the present study, the efficacy of quercetin on the level of lipid peroxides, activities of antioxidant enzymes and tumor marker enzymes in B(a)P induced experimental lung carcinogenesis in Swiss albino mice was assessed. In lung cancer bearing animals there was an increase in lung weight, lipid peroxidation and marker enzymes such as aryl hydrocarbon hydroxylase, gamma glutamyl transpeptidase, 5'-nucleotidase, lactate dehydrogenase and adenosine deaminase with subsequent decrease in body weight and antioxidant enzymes-superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, reduced glutathione, vitamin E and vitamin C. Quercetin supplementation (25 mg/kg body weight) attenuated all these alterations, which indicates the anticancer effect that was further confirmed by histopathological analysis. Overall, the above data shows that the anticancer effect of quercetin is more pronounced when used as an chemopreventive agent rather than as a chemotherapeutic agent against B(a)P induced lung carcinogenesis.
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PMID:The effects of quercetin on antioxidant status and tumor markers in the lung and serum of mice treated with benzo(a)pyrene. 1805 10

Berries contain a number of compounds that are proposed to have anticarcinogenic properties. We wanted to see if pure ellagic acid, natural ellagitannins and three wild berries have any effect on the adenoma formation in Apc- mutated Min/+ mice. Min/+ mice were fed high-fat AIN93-G diets containing 10% (w/w) freeze-dried bilberry (Vaccinium myrtillus), lingonberry (Vaccinium vitis-idaea), cloudberry (Rubus chamaemorus), cloudberry seeds or cloudberry pulp or pure ellagic acid at 1564 mg/kg for 10 weeks. beta-Catenin and cyclin D1 protein levels in the adenomas and in the normal-appearing mucosa were determined by Western blotting and immunohistochemistry. Early changes in gene expression in the normal-appearing mucosa were analyzed by Affymetrix microarrays. Three wild berries significantly reduced tumour number (15-30%, p < 0.05), and cloudberry and lingonberry also reduced tumour size by over 60% (p < 0.01). Cloudberry resulted in decreased levels of nuclear beta-catenin and cyclin D1 and lingonberry in the level of cyclin D1 in the large adenomas (p < 0.05). Affymetrix microarrays revealed changes in genes implicated in colon carcinogenesis, including the decreased expression of the adenosine deaminase, ecto-5f-nucleotidase and PGE2 receptor subtype EP4. Ellagic acid had no effect on the number or size of adenomas in the distal or total small intestine but it increased adenoma size in the duodenum when compared with the control diet (p < 0.05). Neither cloudberry seed nor pulp had any effect on the adenoma formation. Berries seem to have great potential as a source of chemopreventive components.
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PMID:Berries as chemopreventive dietary constituents--a mechanistic approach with the ApcMin/+ mouse. 1829 18

The role of epigenetics in tumor onset and progression has been extensively addressed. Discoveries in the last decade completely changed our view on RNA. We now realize that its diversity lies at the base of biological complexity. Adenosine-to-inosine (A-to-I) RNA editing emerges a central generator of transcriptome diversity and regulation in higher eukaryotes. It is the posttranscriptional deamination of adenosine to inosine in double-stranded RNA catalyzed by enzymes of the adenosine deaminase acting on RNA (ADAR) family. Thought at first to be restricted to coding regions of only a few genes, recent bioinformatic analyses fueled by high-throughput sequencing revealed that it is a widespread modification affecting mostly non-coding repetitive elements in thousands of genes. The rise in scope is accompanied by discovery of a growing repertoire of functions based on differential decoding of inosine by the various cellular machineries: when recognized as guanosine, it can lead to protein recoding, alternative splicing or altered microRNA specificity; when recognized by inosine-binding proteins, it can result in nuclear retention of the transcript or its degradation. An imbalance in expression of ADAR enzymes with consequent editing dysregulation is a characteristic of human cancers. These alterations may be responsible for activating proto-oncogenes or inactivating tumor suppressors. While unlikely to be an early initiating 'hit', editing dysregulation seems to contribute to tumor progression and thus should be considered a 'driver mutation'. In this review, we examine the contribution of A-to-I RNA editing to carcinogenesis.
Carcinogenesis 2011 Nov
PMID:Adenosine-to-inosine RNA editing meets cancer. 2171 63


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