Emmanouela Repapi

University of Leicester, Leicester, ENG, United Kingdom

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Publications (6)91.03 Total impact

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    ABSTRACT: The ability of p53 to regulate transcription is crucial for tumor suppression and implies that inherited polymorphisms in functional p53-binding sites could influence cancer. Here, we identify a polymorphic p53 responsive element and demonstrate its influence on cancer risk using genome-wide data sets of cancer susceptibility loci, genetic variation, p53 occupancy, and p53-binding sites. We uncover a single-nucleotide polymorphism (SNP) in a functional p53-binding site and establish its influence on the ability of p53 to bind to and regulate transcription of the KITLG gene. The SNP resides in KITLG and associates with one of the largest risks identified among cancer genome-wide association studies. We establish that the SNP has undergone positive selection throughout evolution, signifying a selective benefit, but go on to show that similar SNPs are rare in the genome due to negative selection, indicating that polymorphisms in p53-binding sites are primarily detrimental to humans.
    Cell 10/2013; 155(2):410-422. · 31.96 Impact Factor
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    ABSTRACT: The p53 pathway constitutes a major cellular gene network that is crucial in directing the suppression of cancer formation, mediating the response to commonly used cancer therapies, as well as the regulation of germline maintenance, fertility, and reproduction. It has been demonstrated that various cancer predisposition syndromes are caused by low-frequency, highly penetrant inherited mutations in the p53 network, the knowledge of which is already positively affecting patient survival. Mounting evidence from studies utilizing human material, patient cohorts, and mouse models suggests that higher frequency, lesser penetrant genetic variants can also affect p53 signaling, resulting in differences in cancer risk, prognosis, response to therapies, and/or natural selection. Indeed, multiple genes in the p53 network have been shown to harbor functional single nucleotide polymorphisms (SNPs). Comprehensive analyses of two SNPs have demonstrated that their effects on cancer can be modified by factors such as gender, estrogen, and other p53 pathway SNPs. Together these insights suggest that genetic variants in the p53 network could present an excellent opportunity to further define individuals in their abilities to react to stress, suppress tumor formation, and respond to therapies.
    p53 in the Clinics, Edited by Hainaut Pierre, Olivier Magali, Wiman Klas G, 01/2013: chapter The Inheritance of p53: pages 25-46; Springer., ISBN: 978-1-4614-3676-8
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    ABSTRACT: Conventional high-grade osteosarcoma is the most common primary bone malignancy. Although altered expression of the p53 inhibitor HDMX (Mdmx/Mdm4) is associated with cancer risk, progression, and outcome in other tumor types, little is known about its role in osteosarcoma. High expression of the Hdmx splice variant HDMX-S relative to the full-length transcript (the HDMX-S/HDMX-FL ratio) correlates with reduced HDMX protein expression, faster progression, and poorer survival in several cancers. Here, we show that the HDMX-S/HDMX-FL ratio positively correlates with less HDMX protein expression, faster metastatic progression, and a trend to worse overall survival in osteosarcomas. We found that the HDMX-S/HDMX-FL ratio associated with common somatic genetic lesions connected with p53 inhibition, such as p53 mutation and HDM2 overexpression in osteosarcoma cell lines. Interestingly, this finding was not limited to osteosarcomas as we observed similar associations in breast cancer and a variety of other cancer cell lines, as well as in tumors from patients with soft tissue sarcoma. The HDMX-S/HDMX-FL ratio better defined patients with sarcoma with worse survival rates than p53 mutational status. We propose a novel role for alternative splicing of HDMX, whereby it serves as a mechanism by which HDMX protein levels are reduced in cancer cells that have already inhibited p53 activity. Alternative splicing of HDMX could, therefore, serve as a more effective biomarker for p53 pathway attenuation in cancers than p53 gene mutation.
    Cancer Research 06/2012; 72(16):4074-84. · 9.28 Impact Factor
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    ABSTRACT: Genomic loci are associated with FEV1 or the ratio of FEV1 to FVC in population samples, but their association with chronic obstructive pulmonary disease (COPD) has not yet been proven, nor have their combined effects on lung function and COPD been studied. To test association with COPD of variants at five loci (TNS1, GSTCD, HTR4, AGER, and THSD4) and to evaluate joint effects on lung function and COPD of these single-nucleotide polymorphisms (SNPs), and variants at the previously reported locus near HHIP. By sampling from 12 population-based studies (n = 31,422), we obtained genotype data on 3,284 COPD case subjects and 17,538 control subjects for sentinel SNPs in TNS1, GSTCD, HTR4, AGER, and THSD4. In 24,648 individuals (including 2,890 COPD case subjects and 13,862 control subjects), we additionally obtained genotypes for rs12504628 near HHIP. Each allele associated with lung function decline at these six SNPs contributed to a risk score. We studied the association of the risk score to lung function and COPD. Association with COPD was significant for three loci (TNS1, GSTCD, and HTR4) and the previously reported HHIP locus, and suggestive and directionally consistent for AGER and TSHD4. Compared with the baseline group (7 risk alleles), carrying 10-12 risk alleles was associated with a reduction in FEV1 (β = -72.21 ml, P = 3.90 × 10(-4)) and FEV1/FVC (β = -1.53%, P = 6.35 × 10(-6)), and with COPD (odds ratio = 1.63, P = 1.46 × 10(-5)). Variants in TNS1, GSTCD, and HTR4 are associated with COPD. Our highest risk score category was associated with a 1.6-fold higher COPD risk than the population average score.
    American Journal of Respiratory and Critical Care Medicine 10/2011; 184(7):786-95. · 11.04 Impact Factor
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    ABSTRACT: Lung function measures are heritable traits that predict population morbidity and mortality and are essential for the diagnosis of chronic obstructive pulmonary disease (COPD). Variations in many genes have been reported to affect these traits, but attempts at replication have provided conflicting results. Recently, we undertook a meta-analysis of Genome Wide Association Study (GWAS) results for lung function measures in 20,288 individuals from the general population (the SpiroMeta consortium). To comprehensively analyse previously reported genetic associations with lung function measures, and to investigate whether single nucleotide polymorphisms (SNPs) in these genomic regions are associated with lung function in a large population sample. We analysed association for SNPs tagging 130 genes and 48 intergenic regions (+/-10 kb), after conducting a systematic review of the literature in the PubMed database for genetic association studies reporting lung function associations. The analysis included 16,936 genotyped and imputed SNPs. No loci showed overall significant association for FEV(1) or FEV(1)/FVC traits using a carefully defined significance threshold of 1.3×10(-5). The most significant loci associated with FEV(1) include SNPs tagging MACROD2 (P = 6.81×10(-5)), CNTN5 (P = 4.37×10(-4)), and TRPV4 (P = 1.58×10(-3)). Among ever-smokers, SERPINA1 showed the most significant association with FEV(1) (P = 8.41×10(-5)), followed by PDE4D (P = 1.22×10(-4)). The strongest association with FEV(1)/FVC ratio was observed with ABCC1 (P = 4.38×10(-4)), and ESR1 (P = 5.42×10(-4)) among ever-smokers. Polymorphisms spanning previously associated lung function genes did not show strong evidence for association with lung function measures in the SpiroMeta consortium population. Common SERPINA1 polymorphisms may affect FEV(1) among smokers in the general population.
    PLoS ONE 01/2011; 6(5):e19382. · 3.53 Impact Factor
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    ABSTRACT: Pulmonary function measures are heritable traits that predict morbidity and mortality and define chronic obstructive pulmonary disease (COPD). We tested genome-wide association with forced expiratory volume in 1 s (FEV(1)) and the ratio of FEV(1) to forced vital capacity (FVC) in the SpiroMeta consortium (n = 20,288 individuals of European ancestry). We conducted a meta-analysis of top signals with data from direct genotyping (n < or = 32,184 additional individuals) and in silico summary association data from the CHARGE Consortium (n = 21,209) and the Health 2000 survey (n < or = 883). We confirmed the reported locus at 4q31 and identified associations with FEV(1) or FEV(1)/FVC and common variants at five additional loci: 2q35 in TNS1 (P = 1.11 x 10(-12)), 4q24 in GSTCD (2.18 x 10(-23)), 5q33 in HTR4 (P = 4.29 x 10(-9)), 6p21 in AGER (P = 3.07 x 10(-15)) and 15q23 in THSD4 (P = 7.24 x 10(-15)). mRNA analyses showed expression of TNS1, GSTCD, AGER, HTR4 and THSD4 in human lung tissue. These associations offer mechanistic insight into pulmonary function regulation and indicate potential targets for interventions to alleviate respiratory disease.
    Nature Genetics 12/2009; 42(1):36-44. · 35.21 Impact Factor