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13 result(s) for "Panoutsopoulou, K"
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EP1277 Clinical evaluation of miR-34a in ovarian carcinoma
Introduction/BackgroundOvarian cancer (OC) is the most common cause of gynecological cancer-related death in developed countries. The absence of evident early symptoms and effective asymptomatic population screening leads to diagnosis in advanced stages for the majority of patients and, thus, to poor prognosis. Consequently, the identification of predictive markers of patients´ treatment outcome could ameliorate disease management. microRNA-34a (miR-34a) is highlighted to exert a tumor suppressive role in several malignancies and is downregulated in numerous cancers. According to TarBase v.8, highthroughput studies have reported the negative correlation of miR-34a with kallikrein-related peptidase 6 (KLK6) expression levels. In the present study, we aimed to investigate the expression profile of miR-34a in ovarian carcinomas and to explore its clinical value in OC patients.MethodologyOvarian cancer specimens and matched adjacent tissues were obtained from St. Savvas Regional Anticancer Oncology Hospital of Athens. Following homogenization, total RNA was extracted using TRI reagent. Thereafter, the RNA was polyadenylated in the 3’-end and first-strand cDNA synthesis was performed by MMLV using an oligo (dT) adapter. A SYBR-Green fluorescent-based qPCR assay was developed to quantify miR-34a, using snoRNA RNU48 as endogenous reference control gene for normalization purposes. Extensive statistical analysis has been conducted to explore the clinical utility of miR-34a levels.ResultsThe expression analysis demonstrated that miR-34a levels are downregulated in ovarian tumors compared to normal epithelium. With regard to clinicopathological characteristics, patients with tumor grade 3 (G3) were highlighted to underexpress miR-34a compared to OC patients with tumor grade 1 (G1) or 2 (G2). Ultimately, no association was observed between FIGO stages and miR-34a expression levels.ConclusionThe tumor-suppressor miR-34a is downregulated in ovarian malignant epithelium and correlated with higher tumor grading, supporting its further evaluation as a potential molecular marker in OC prognosis.DisclosureNothing to disclose
Short term starvation potentiates the efficacy of chemotherapy in triple negative breast cancer via metabolic reprogramming
Background Chemotherapy (CT) is central to the treatment of triple negative breast cancer (TNBC), but drug toxicity and resistance place strong restrictions on treatment regimes. Fasting sensitizes cancer cells to a range of chemotherapeutic agents and also ameliorates CT-associated adverse effects. However, the molecular mechanism(s) by which fasting, or short-term starvation (STS), improves the efficacy of CT is poorly characterized. Methods The differential responses of breast cancer or near normal cell lines to combined STS and CT were assessed by cellular viability and integrity assays (Hoechst and PI staining, MTT or H 2 DCFDA staining, immunofluorescence), metabolic profiling (Seahorse analysis, metabolomics), gene expression (quantitative real-time PCR) and iRNA-mediated silencing. The clinical significance of the in vitro data was evaluated by bioinformatical integration of transcriptomic data from patient data bases: The Cancer Genome Atlas (TCGA), European Genome-phenome Archive (EGA), Gene Expression Omnibus (GEO) and a TNBC cohort. We further examined the translatability of our findings in vivo by establishing a murine syngeneic orthotopic mammary tumor-bearing model. Results We provide mechanistic insights into how preconditioning with STS enhances the susceptibility of breast cancer cells to CT. We showed that combined STS and CT enhanced cell death and increased reactive oxygen species (ROS) levels, in association with higher levels of DNA damage and decreased mRNA levels for the NRF2 targets genes NQO1 and TXNRD1 in TNBC cells compared to near normal cells. ROS enhancement was associated with compromised mitochondrial respiration and changes in the metabolic profile, which have a significant clinical prognostic and predictive value. Furthermore, we validate the safety and efficacy of combined periodic hypocaloric diet and CT in a TNBC mouse model. Conclusions Our in vitro, in vivo and clinical findings provide a robust rationale for clinical trials on the therapeutic benefit of short-term caloric restriction as an adjuvant to CT in triple breast cancer treatment.
Genome-wide association study in a Chinese population identifies a susceptibility locus for type 2 diabetes at 7q32 near PAX4
Aims/hypothesis Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians. Methods We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations. Results We identified CDKN2A/B and four novel type 2 diabetes association signals with p  < 1 × 10 −5 from the meta-analysis. Thirteen variants within these four loci were followed up in two independent Chinese cohorts, and rs10229583 at 7q32 was found to be associated with type 2 diabetes in a combined analysis of 11,067 cases and 7,929 controls ( p meta  = 2.6 × 10 −8 ; OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations ( p meta  = 2.3 × 10 −10 ) and a population of European descent ( p  = 8.6 × 10 −3 ). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians. Conclusions/interpretation Our study identifies rs10229583 near PAX4 as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.
Global analysis of nutrient control of gene expression in Saccharomyces cerevisiae during growth and starvation
Global gene expression in yeast was examined in five different nutrient-limited steady states and in their corresponding starvation-induced stationary phases. The use of chemostats, with their ability to generate defined and reproducible physiological conditions, permitted the exclusion of the confounding variables that frequently complicate transcriptome analyses. This approach allowed us to dissect out effects on gene expression that are specific to particular physiological states. Thus, we discovered that a large number of ORFs involved in protein synthesis were activated under ammonium limitation, whereas the expression of ORFs concerned with energy and metabolism was enhanced by carbon limitation. Elevated transcription of genes in high-affinity glucose uptake, the trichloroacetic acid cycle, and oxidative phosphorylation were observed in glucose-limiting, but not glucose-abundant, conditions. In contrast, genes involved in gluconeogenesis and, interestingly, genes subject to nitrogen catabolite repression increased their transcription when ethanol was the carbon source, even though ammonium was in excess. This result suggests that up-regulation of genes sensitive to nitrogen catabolite repression may contribute anapleurotic intermediates in ethanol-grown cells. The different starvation conditions produced two general types of transcription profiles, with carbon-starved cells transcribing far fewer genes than cells starved for any of the other macronutrients. Nonetheless, each starvation condition induced its own peculiar set of genes, and only 17 genes were induced >5-fold by all five starvations. In all cases, analysis of the upstream sequences of clusters of coregulated genes identified motifs that may be recognized by transcription factors specific for controlling gene expression in each of the physiological conditions examined.
Insights into the genetic architecture of osteoarthritis from stage 1 of the arcOGEN study
Objectives The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis. Methods The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent. Results None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects. Conclusions Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.
Cutaneous toxicities of antineoplastic agents: data from a large cohort of Greek patients
PurposeCutaneous toxicities from novel anticancer treatments are an emerging problem in dermato-oncology. However, the prevalence of those toxicities and necessity of skin consultations are currently unknown. The purpose of our study was to perform an epidemiologic analysis of cutaneous toxicities that were referred to our cutaneous toxicity clinic in Athens, Greece.MethodsAll patients examined at the oncodermatology department over a 42-month period were included. Gender, age, type of cancer, type of antineoplastic treatment, and type of toxicity were recorded and analyzed.ResultsFour hundred fifty-nine patients (182 males, 277 females) with mean age (SD) 60.6 years (13.05) were included in the analysis. Six hundred seventy-two cutaneous toxicities were recorded. Chemotherapy-induced toxicities were the most commonly recorded incidents, with taxanes being the most commonly involved agent. Immune-related adverse events (IRAEs) have steadily increased over the past 3 years. Treatment modifications due to skin toxicities were more common in patients treated with targeted agents and immune checkpoint inhibitors than in those treated with chemotherapy. The toxicities that led to the most treatment modifications were acneiform eruptions and perionychias. The most common IRAEs recorded were psoriasis in 11 patients, followed by pruritus, macular rash, and lichenoid-type eruptions. In addition, 4 interesting cases of IRAEs are discussed.ConclusionAntineoplastic treatments can lead to a wide range of cutaneous toxicities. Our study underlines the need for a multidisciplinary approach in oncologic patients. The dermatologists’ role is crucial in effectively managing those reactions and preventing antineoplastic drug dose adjustments or discontinuation of treatment.
A rare functional cardioprotective APOC3 variant has risen in frequency in distinct population isolates
Isolated populations can empower the identification of rare variation associated with complex traits through next generation association studies, but the generalizability of such findings remains unknown. Here we genotype 1,267 individuals from a Greek population isolate on the Illumina HumanExome Beadchip, in search of functional coding variants associated with lipids traits. We find genome-wide significant evidence for association between R19X, a functional variant in APOC3 , with increased high-density lipoprotein and decreased triglycerides levels. Approximately 3.8% of individuals are heterozygous for this cardioprotective variant, which was previously thought to be private to the Amish founder population. R19X is rare (<0.05% frequency) in outbred European populations. The increased frequency of R19X enables discovery of this lipid traits signal at genome-wide significance in a small sample size. This work exemplifies the value of isolated populations in successfully detecting transferable rare variant associations of high medical relevance. Isolated populations may empower genetic association studies of complex traits. Here, the authors identify a rare cardioprotective APOC3 variant in a Greek population isolate and highlight the value of using population isolates to detect rare variants that confer disease risk.
Radiographic endophenotyping in hip osteoarthritis improves the precision of genetic association analysis
ObjectiveOsteoarthritis (OA) has a strong genetic component but the success of previous genome-wide association studies (GWAS) has been restricted due to insufficient sample sizes and phenotype heterogeneity. Our aim was to examine the effect of clinically relevant endophenotyping according to site of maximal joint space narrowing (maxJSN) and bone remodelling response on GWAS signal detection in hip OA.MethodsA stratified GWAS meta-analysis was conducted in 2118 radiographically defined hip OA cases and 6500 population-based controls. Signals were followed up by analysing differential expression of proximal genes for bone remodelling endophenotypes in 33 pairs of macroscopically intact and OA-affected cartilage.ResultsWe report suggestive evidence (p<5×10−6) of association at 6 variants with OA endophenotypes that would have been missed by using presence of hip OA as the disease end point. For example, in the analysis of hip OA cases with superior maxJSN versus cases with non-superior maxJSN we detected association with a variant in the LRCH1 gene (rs754106, p=1.49×10−7, OR (95% CIs) 0.70 (0.61 to 0.80)). In the comparison of hypertrophic with non-hypertrophic OA the most significant variant was located between STT3B and GADL1 (rs6766414, p=3.13×10−6, OR (95% CIs) 1.45 (1.24 to 1.69)). Both of these associations were fully attenuated in non-stratified analyses of all hip OA cases versus population controls (p>0.05). STT3B was significantly upregulated in OA-affected versus intact cartilage, particularly in the analysis of hypertrophic and normotrophic compared with atrophic bone remodelling pattern (p=4.2×10−4).ConclusionsOur findings demonstrate that stratification of OA cases into more homogeneous endophenotypes can identify genes of potential functional importance otherwise obscured by disease heterogeneity.
Gene Expression Meta-Analysis of Potential Shared and Unique Pathways between Autoimmune Diseases under Anti-TNFα Therapy
While anti-TNFα has been established as an effective therapeutic approach for several autoimmune diseases, results from clinical trials have uncovered heterogeneous patients’ response to therapy. Here, we conducted a meta-analysis on the publicly available gene expression cDNA microarray datasets that examine the differential expression observed in response to anti-TNFα therapy with psoriasis (PsO), inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). Five disease-specific meta-analyses and a single combined random-effects meta-analysis were performed through the restricted maximum likelihood method. Gene Ontology and Reactome Pathways enrichment analyses were conducted, while interactions between differentially expressed genes (DEGs) were determined with the STRING database. Four IBD, three PsO and two RA datasets were identified and included in our analyses through our search criteria. Disease-specific meta-analyses detected distinct pro-inflammatory down-regulated DEGs for each disease, while pathway analyses identified common inflammatory patterns involved in the pathogenesis of each disease. Combined meta-analyses further revealed DEGs that participate in anti-inflammatory pathways, namely IL-10 signaling. Our analyses provide the framework for a transcriptomic approach in response to anti-TNFα therapy in the above diseases. Elucidation of the complex interactions involved in such multifactorial phenotypes could identify key molecular targets implicated in the pathogenesis of IBD, PsO and RA.