| 551. |
- Riddle, Nicole C, et al.
(författare)
-
Enrichment of HP1a on drosophila chromosome 4 genes creates an alternate chromatin structure critical for regulation in this heterochromatic domain
- 2012
-
Ingår i: PLOS Genetics. - : Public Library of Science, PLOS. - 1553-7390 .- 1553-7404. ; 8:9, s. e1002954-
-
Tidskriftsartikel (refereegranskat)abstract
- Chromatin environments differ greatly within a eukaryotic genome, depending on expression state, chromosomal location, and nuclear position. In genomic regions characterized by high repeat content and high gene density, chromatin structure must silence transposable elements but permit expression of embedded genes. We have investigated one such region, chromosome 4 of Drosophila melanogaster. Using chromatin-immunoprecipitation followed by microarray (ChIP-chip) analysis, we examined enrichment patterns of 20 histone modifications and 25 chromosomal proteins in S2 and BG3 cells, as well as the changes in several marks resulting from mutations in key proteins. Active genes on chromosome 4 are distinct from those in euchromatin or pericentric heterochromatin: while there is a depletion of silencing marks at the transcription start sites (TSSs), HP1a and H3K9me3, but not H3K9me2, are enriched strongly over gene bodies. Intriguingly, genes on chromosome 4 are less frequently associated with paused polymerase. However, when the chromatin is altered by depleting HP1a or POF, the RNA pol II enrichment patterns of many chromosome 4 genes shift, showing a significant decrease over gene bodies but not at TSSs, accompanied by lower expression of those genes. Chromosome 4 genes have a low incidence of TRL/GAGA factor binding sites and a low T-m downstream of the TSS, characteristics that could contribute to a low incidence of RNA polymerase pausing. Our data also indicate that EGG and POF jointly regulate H3K9 methylation and promote HP1a binding over gene bodies, while HP1a targeting and H3K9 methylation are maintained at the repeats by an independent mechanism. The HP1a-enriched, POF-associated chromatin structure over the gene bodies may represent one type of adaptation for genes embedded in repetitive DNA.
|
|
| 552. |
- Roy, Sushmita, et al.
(författare)
-
Identification of functional elements and regulatory circuits by Drosophila modENCODE.
- 2010
-
Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 330:6012, s. 1787-1797
-
Tidskriftsartikel (refereegranskat)abstract
- To gain insight into how genomic information is translated into cellular and developmental programs, the Drosophila model organism Encyclopedia of DNA Elements (modENCODE) project is comprehensively mapping transcripts, histone modifications, chromosomal proteins, transcription factors, replication proteins and intermediates, and nucleosome properties across a developmental time course and in multiple cell lines. We have generated more than 700 data sets and discovered protein-coding, noncoding, RNA regulatory, replication, and chromatin elements, more than tripling the annotated portion of the Drosophila genome. Correlated activity patterns of these elements reveal a functional regulatory network, which predicts putative new functions for genes, reveals stage- and tissue-specific regulators, and enables gene-expression prediction. Our results provide a foundation for directed experimental and computational studies in Drosophila and related species and also a model for systematic data integration toward comprehensive genomic and functional annotation.
|
|
| 553. |
- Sacco, R. L., et al.
(författare)
-
Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke
- 2008
-
Ingår i: New England Journal of Medicine. - Boston : Massachusetts medical society. - 1533-4406 .- 0028-4793. ; 359:12, s. 1238-51
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared the efficacy and safety of two antiplatelet regimens--aspirin plus extended-release dipyridamole (ASA-ERDP) versus clopidogrel. METHODS: In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive 25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive 75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke. The secondary outcome was a composite of stroke, myocardial infarction, or death from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075), followed by superiority testing, was planned. RESULTS: A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke occurred in 916 patients (9.0%) receiving ASA-ERDP and in 898 patients (8.8%) receiving clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for ASA-ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events among ASA-ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365 [3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage (hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major hemorrhagic event was similar in the two groups (1194 ASA-ERDP recipients [11.7%], vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11). CONCLUSIONS: The trial did not meet the predefined criteria for noninferiority but showed similar rates of recurrent stroke with ASA-ERDP and with clopidogrel. There is no evidence that either of the two treatments was superior to the other in the prevention of recurrent stroke. (ClinicalTrials.gov number, NCT00153062.)
|
|
| 554. |
- Salehi, Amir M., et al.
(författare)
-
Patients with oral tongue squamous cell carcinoma and co‑existing diabetes exhibit lower recurrence rates and improved survival : implications for treatment
- 2024
-
Ingår i: Oncology Letters. - : Spandidos Publications. - 1792-1074 .- 1792-1082. ; 27:4
-
Tidskriftsartikel (refereegranskat)abstract
- Locoregional recurrences and distant metastases are major problems for patients with squamous cell carcinoma of the head and neck (SCCHN). Because SCCHN is a heterogeneous group of tumours with varying characteristics, the present study concentrated on the subgroup of squamous cell carcinoma of the oral tongue (SCCOT) to investigate the use of machine learning approaches to predict the risk of recurrence from routine clinical data available at diagnosis. The approach also identified the most important parameters that identify and classify recurrence risk. A total of 66 patients with SCCOT were included. Clinical data available at diagnosis were analysed using statistical analysis and machine learning approaches. Tumour recurrence was associated with T stage (P=0.001), radiological neck metastasis (P=0.010) and diabetes (P=0.003). A machine learning model based on the random forest algorithm and with attendant explainability was used. Whilst patients with diabetes were overrepresented in the SCCOT cohort, diabetics had lower recur‑ rence rates (P=0.015 after adjusting for age and other clinical features) and an improved 2‑year survival (P=0.025) compared with non‑diabetics. Clinical, radiological and histological data available at diagnosis were used to establish a prognostic model for patients with SCCOT. Using machine learning to predict recurrence produced a classification model with 71.2% accuracy. Notably, one of the findings of the feature importance rankings of the model was that diabetics exhibited less recur‑ rence and improved survival compared with non‑diabetics, even after accounting for the independent prognostic variables of tumour size and patient age at diagnosis. These data imply that the therapeutic manipulation of glucose levels used to treatdiabetes may be useful for patients with SCCOT regardless of their diabetic status. Further studies are warranted to investigatethe impact of diabetes in other SCCHN subtypes.
|
|
| 555. |
- Salehi, Amir M., et al.
(författare)
-
Reiterative modeling of combined transcriptomic and proteomic features refines and improves the prediction of early recurrence in squamous cell carcinoma of head and neck
- 2022
-
Ingår i: Computers in Biology and Medicine. - : Elsevier. - 0010-4825 .- 1879-0534. ; 149
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Patients with squamous cell carcinoma of the head and neck (SCCHN) have a high-risk of recurrence. We aimed to develop machine learning methods to identify transcriptomic and proteomic features that provide accurate classification models for predicting risk of early recurrence in SCCHN patients.Methods: Clinical, genomic, transcriptomic and proteomic features distinguishing recurrence risk were examined in SCCHN patients from The Cancer Genome Atlas (TCGA). Recurrence within one year after treatment was classified as high-risk and no recurrence as low-risk.Results: No significant differences in individual clinicopathological characteristics, mutation profiles or mRNA expression patterns were seen between the groups using conventional statistical analysis. Using the machine learning algorithm, extreme gradient boosting (XGBoost), ten proteins (RAD50, 4E-BP1, MYH11, MAP2K1, BECN1, NF2, RAB25, ERRFI1, KDR, SERPINE1) and five mRNAs (PLAUR, DKK1, AXIN2, ANG and VEGFA) made the greatest contribution to classification. These features were used to build improved models in XGBoost, achieving the best discrimination performance when combining transcriptomic and proteomic data, providing an accuracy of 0.939 and an Area Under the ROC Curve (AUC) of 0.951.Conclusions: This study highlights machine learning to identify transcriptomic and proteomic factors that play important roles in predicting risk of recurrence in patients with SCCHN and to develop such models by iterative cycles to enhance their accuracy, thereby aiding the introduction of personalized treatment regimens.
|
|
| 556. |
|
|
| 557. |
- Schwartz, Yuri B, et al.
(författare)
-
Nature and function of insulator protein binding sites in the Drosophila genome
- 2012
-
Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 22, s. 2188-2198
-
Tidskriftsartikel (refereegranskat)abstract
- Chromatin insulator elements and associated proteins have been proposed to partition eukaryotic genomes into sets of independently regulated domains. Here we test this hypothesis by quantitative genome-wide analysis of insulator protein binding to Drosophila chromatin. We find distinct combinatorial binding of insulator proteins to different classes of sites and uncover a novel type of insulator element that binds CP190 but not any other known insulator proteins. Functional characterization of different classes of binding sites indicates that only a small fraction act as robust insulators in standard enhancer-blocking assays. We show that insulators restrict the spreading of the H3K27me3 mark but only at a small number of Polycomb target regions and only to prevent repressive histone methylation within adjacent genes that are already transcriptionally inactive. RNAi knockdown of insulator proteins in cultured cells does not lead to major alterations in genome expression. Taken together these observations argue against the concept of a genome partitioned by specialized boundary elements and suggest that insulators are reserved for specific regulation of selected genes.
|
|
| 558. |
- Sgaramella, Nicola, et al.
(författare)
-
Ethnicity based variation in expression of E-cadherin in patients with squamous cell carcinoma of the oral tongue
- 2018
-
Ingår i: Oncology Letters. - : Spandidos Publications. - 1792-1074 .- 1792-1082. ; 16:5, s. 6603-6607
-
Tidskriftsartikel (refereegranskat)abstract
- The oral tongue is the most common site for tumours within the oral cavity. Despite intense research, there has been no improvement in the survival rate for patients with oral tongue squamous cell carcinoma (OTSCC) during the last decades. Differences between oral cancer patients based on ethno-geographical distribution have been reported. The present study used immunohistochemistry to evaluate commonly used markers of cancer cell phenotypes, E-cadherin, -catenin and cytokeratins 5 and 19, in 120 patients with OTSCC. To evaluate the impact of ethnicity, patients from Sweden and Italy were included. A higher proportion of Swedish patients exhibited high expression of E-cadherin in their tumours (P=0.039), and high levels of E-cadherin in Swedish OTSCC patients that had succumbed to their disease were associated with poor prognosis. These data demonstrated differences in the pathological characteristics of OTSCC between two different European populations. The findings emphasise the need to take ethnicity/geographical location of patients into account when comparing results from different studies of OTSCC.
|
|
| 559. |
- Sgaramella, Nicola, et al.
(författare)
-
Searching for new targets and treatments in the battle against squamous cell carcinoma of the head and neck, with specific focus on tumours of the tongue
- 2018
-
Ingår i: Current Topics in Medicinal Chemistry. - : Bentham Science Publishers. - 1568-0266 .- 1873-4294. ; 18:3, s. 214-218
-
Forskningsöversikt (refereegranskat)abstract
- Squamous cell carcinoma of the head and neck, SCCHN, is a heterogeneous group of tumours not only concerning the site of origin but also regarding aetiology. The 5-year survival for the whole group of SCCHN tumours has not significantly improved over the last 20-25 years. Apart from tumour spread to lymph nodes, N status, gains and losses of specific chromosomes are the only factors shown to be independent prognostic markers for these tumours. Worldwide, an increasing number of people ≤ 40 years are seen being affected by tongue SCC, the most common tumour within the SCCHN group. Even without any clinical signs of metastasis, up to 30% of all tongue SCC have histologically detectable spread to lymph nodes. In this mini review, field cancerization, tumour microenvironment, the so called EMT (epithelial mesenchymal transition) process and the role of viruses in development of SCCHN are discussed as well as potential new therapeutic targets. For the group of tongue SCC, with the increasing incidence seen in young patients and particularly women, new data with impact on prognosis and treatment are urgently needed. But as long as data from the analyses of several sub sites are presented as valid for the whole group of tumours, this vital point is missed.
|
|
| 560. |
|
|
