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Reactivation of a silenced
Background The active copy of the imprinted gene H19 is turned off by inappropriate methylation in several pediatric tumors including Wilms' Tumour and embryonal rhabdomyosarcoma. H19 controls in cis the linked Insulin-like Growth Factor 2 (IGF2) gene, encoding an important growth factor. Recent work has suggested that methylation of a gene may lead to deacetylation of its associated histones and that silenced genes can be reactivated by increasing histone acetylation levels. Results Treatment of a rhabdomyosarcoma cell line which has a silent, methylated H19 gene with histone deacetylase (HDAC) inhibitors under conditions which gave maximal hyperacetylation of histone 4, both globally and at the H19 gene itself could not reactivate H19 or affect the active Insulin-like Growth Factor 2 (IGF2) gene, but caused clear up-regulation of the Tissue-type Plasminogen Activator (TPA) gene, a non-imprinted gene known to respond to changes in histone acetylation. In contrast, mild treatment of the cells with the methylation inhibitor 5-AzaC-2'-deoxycytidine (AzaC) on its own was able to reactivate H19. Combining AzaC treatment with HDAC inhibitors gave a reduced rather than enhanced reactivation. These findings were confirmed in mouse primary liver and kidney explants which maintain normal imprinting, where we also found that the silent Igf2 gene could not be reactivated by HDAC inhibitors. Conclusion These results suggest that DNA methylation rather than histone acetylation is the primary determinant of silencing of H19 in rhabdomyosarcoma.
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Mutation analysis of the CHK2 gene in breast carcinoma and other cancers
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Background Mutations in the CHK2 gene at chromosome 22q12.1 have been reported in families with Li-Fraumeni syndrome. Chk2 is an effector kinase that is activated in response to DNA damage and is involved in cell-cycle pathways and p53 pathways. Methods We screened 139 breast tumors for loss of heterozygosity at chromosome 22q, using seven microsatellite markers, and screened 119 breast tumors with single-strand conformation polymorphism and DNA sequencing for mutations in the CHK2 gene. Results Seventy-four of 139 sporadic breast tumors (53%) show loss of heterozygosity with at least one marker. These samples and 45 tumors from individuals carrying the BRCA2 999del5 mutation were screened for mutations in the CHK2 gene. In addition to putative polymorphic regions in short mononucleotide repeats in a non-coding exon and intron 2, a germ line variant (T59K) in the first coding exon was detected. On screening 1172 cancer patients for the T59K sequence variant, it was detected in a total of four breast-cancer patients, two colon-cancer patients, one stomach-cancer patient and one ovary-cancer patient, but not in 452 healthy individuals. A tumor-specific 5' splice site mutation at site +3 in intron 8 (TTgt [a → c]atg) was also detected. Conclusion We conclude that somatic CHK2 mutations are rare in breast cancer, but our results suggest a tumor suppressor function for CHK2 in a small proportion of breast tumors. Furthermore, our results suggest that the T59K CHK2 sequence variant is a low-penetrance allele with respect to tumor growth.
Receptor protein tyrosine kinase EphB4 is up-regulated in colon cancer
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Background We have used commercially available cDNA arrays to identify EphB4 as a gene that is up-regulated in colon cancer tissue when compared with matched normal tissue from the same patient. Results Quantitative RT-PCR analysis of the expression of the EphB4 gene has shown that its expression is increased in 82% of tumour samples when compared with the matched normal tissue from the same patient. Using immunohistochemistry and Western analysis techniques with an EphB4-specific antibody, we also show that this receptor is expressed in the epithelial cells of the tumour tissue and either not at all, or in only low levels, in the normal tissue. Conclusion The results presented here supports the emerging idea that Eph receptors play a role in tumour formation and suggests that further elucidation of this signalling pathway may identify useful targets for cancer treatment therapies.
IgVH genes from different anatomical regions, with different histopathological patterns, of a rheumatoid arthritis patient suggest cyclic re-entry of mature synovial B-cells in the hypermutation process
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In the present study 55 IgVH genes amplified from three different anatomical regions of a rheumatoid arthritis (RA) patient were analyzed, adding further information on synovial B-cell maturation and recirculation in RA. This analysis demonstrated somatically mutated IgVh genes in all regions studied, with amino acid deletions and mixed IgVh molecules, suggesting the existence of a novel pathway to generate (auto) antibody specificities. Comparison of amino acid sequences of amplified genes that belong to the VH1 family (with predominantly the same germline counterpart) exhibited strong homology, indicating an apparently conserved mutational pattern. This suggests that the number of antigens that activate B cells in different locations is restricted. The most striking result was the finding of clonally related sequences in different anatomical regions, indicating a recirculation of activated B cells between the different affected joints.
TheG-308Avariant of the Tumor Necrosis Factor-α (TNF-α) gene is not associated with obesity, insulin resistance and body fat distribution
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Background Tumor Necrosis Factor-α (TNF-α) has been implicated in the pathogenesis of insulin resistance and obesity. The increased expression of TNF-α in adipose tissue has been shown to induce insulin resistance, and a polymorphism at position -308 in the promoter region ofTNF-α has been shown to increase transcription of the gene in adipocytes. Aim of this study is to investigate the role of the G-308A TNFα variant in obesity and to study the possible influence of this mutation on body fat distribution and on measures of obesity (including Fat Free Mass, Fat Mass, basal metabolic rate), insulin resistance (measured as HOMAIR), and lipid abnormalities. The G-308A TNFα polymorphism has been studied in 115 patients with obesity (mean BMI 33.9 ± 0.5) and in 79 normal lean subjects (mean BMI 24.3 ± 0.3). Methods The G-308A variant, detected by PCR amplification and Nco-1 digestion, determines the loss of a restriction site resulting in a single band of 107 bp [the (A) allele]. Results The (A) allele frequencies of the G-308A TNFα polymorphism were 13.1% in the obese group and 14.6% in the lean subjects, with no significant difference between the two groups. Furthermore, no association was found with BMI classes, body fat distribution, HOMAIR, and metabolic abnormalities. Conclusions Our study did not detect any significant association of the G-308A TNFα polymorphism with obesity or with its clinical and metabolic abnormalities in this population. Our data suggests that, in our population, the G-308A TNFα polymorphism is unlikely to play a major role in the pathogenesis of these conditions.
2017 Prediction of H295R steroidogenesis Pathway Perturbation
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The objectives of this work were to: 1) develop an integrated analysis of chemical-mediated effects on steroidogenesis in the HT-H295R assay; and, 2) evaluate whether the HT-H295R assay predicts estrogen and androgen production specifically via comparison with the OECD-validated H295R assay. This dataset is associated with the following publication: Haggard, D., A. Karmaus, M. Martin, R. Judson, W. Setzer, and K. Paul-Friedman. (Toxicological Sciences) High-throughput H295R steroidogenesis assay: utility as an alternative and a statistical approach to characterize effects on steroidogenesis. TOXICOLOGICAL SCIENCES. Society of Toxicology, RESTON, VA, 162(2): 509-534, (2018).
2017 Prediction of H295R steroidogenesis Pathway Perturbation
공공데이터포털
The objectives of this work were to: 1) develop an integrated analysis of chemical-mediated effects on steroidogenesis in the HT-H295R assay; and, 2) evaluate whether the HT-H295R assay predicts estrogen and androgen production specifically via comparison with the OECD-validated H295R assay. This dataset is associated with the following publication: Haggard, D., A. Karmaus, M. Martin, R. Judson, W. Setzer, and K. Paul-Friedman. (Toxicological Sciences) High-throughput H295R steroidogenesis assay: utility as an alternative and a statistical approach to characterize effects on steroidogenesis. TOXICOLOGICAL SCIENCES. Society of Toxicology, RESTON, VA, 162(2): 509-534, (2018).
Dataset for ORD-040056: Development and Validation of the TGx-HDACi Transcriptomic Biomarker to Detect Histone Deacetylase Inhibitors in Human TK6 Cells
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Dataset used to determine the predictive accuracy of the HDACi biomarker. This dataset is associated with the following publication: Cho, E., A. Rowan-Carroll, A. Williams, C. Corton, H. Li, A. Fornace, C. Hobbs, and C. Yauk. Development and Validation of the TGx-HDACi Transcriptomic Biomarker to Detect Histone Deacetylase Inhibitors in Human TK6 Cells. Archives of Toxicology. Springer, New York, NY, USA, 95(5): 1631-1645, (2021).
NF-kappaB in rheumatoid arthritis: a pivotal regulator of inflammation, hyperplasia, and tissue destruction
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The transcription factor NF-κB has been well recognized as a pivotal regulator of inflammation in rheumatoid arthritis (RA), but recent developments revealed a broad involvement of NF-κB in other aspects of RA pathology, including development of T helper 1 responses, activation, abnormal apoptosis and proliferation of RA fibroblast-like synovial cells, and differentiation and activation of bone resorbing activity of osteoclasts. In agreement with this, studies in animal models of RA have demonstrated the high therapeutic efficacy of specific inhibitors of NF-κB pathway, indicating the feasibility of anti-NF-κB therapy for human disease.
Proton Irradiation Impacts Age Driven Modulations of Cancer Progression Influenced by Immune System Transcriptome Modifications from Splenic Tissue
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Age plays a crucial role in the interplay between tumor and host; with further perturbations induced by irradiation. Proton irradiation on tumors induces biological modulations including inhibition of angiogenic and immune factors critical to hallmark processes impacting tumor development in addition to physical targeting advantages. These advantages have provided promising results for proton therapy in cancer. Additionally protons have implications for carcinogenesis risk of space travel (due to the high proportion of high energy protons in space radiation). Through a systems biology approach we investigated how host tissue (i.e. splenic tissue) of tumor-bearing mice is altered with age with or without whole-body proton exposure. Transcriptome analysis was performed on splenic tissue from adolescent (68 day) versus old (736 day) C57BL/6 male mice injected with Lewis lung carcinoma cells with or without three fractionations of 0.5Gy (1GeV) proton irradiation. Global transcriptome analysis indicated that proton irradiation of adolescent hosts caused significant signaling changes within splenic tissues that support carcinogenesis within the mice as compared to old subjects. Increases in cell cycling and immunosuppression in irradiated adolescent hosts with CDK2 MCM7 CD74 and RUVBL2 as the key players were involved in the regulatory changes in host environment response (i.e. spleen). These results suggest a significant biological component to proton irradiation operative through host age that would indicate a modulation of host s ability to support carcinogenesis in adolescence and the bestowal of resistance to immunosuppression carcinogenesis and genetic perturbation by old age.