| 31. |
- Milani, Lili, et al.
(författare)
-
Allelic imbalance in gene expression as a guide to cis-acting regulatory single nucleotide polymorphisms in cancer cells
- 2007
-
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 35:5, s. E34-
-
Tidskriftsartikel (refereegranskat)abstract
- Using the relative expression levels of two SNIP alleles of a gene in the same sample is an effective approach for identifying cis-acting regulatory SNPs (rSNPs). In the current study, we established a process for systematic screening for cis-acting rSNPs using experimental detection of Al as an initial approach. We selected 160 expressed candidate genes that are involved in cancer and anticancer drug resistance for analysis of All in a panel of cell lines that represent different types of cancers and have been well characterized for their response patterns against anticancer drugs. Of these genes, 60 contained heterozygous SNPs in their coding regions, and 41 of the genes displayed imbalanced expression of the two cSNP alleles. Genes that displayed Al were subjected to bioinformatics-assisted identification of rSNPs that alter the strength of transcription factor binding. rSNPs in 15 genes were subjected to electrophoretic mobility shift assay, and in eight of these genes (APC, BCL2, CCND2, MLH1, PARP1, SLIT2, YES1, XRCC1) we identified differential protein binding from a nuclear extract between the SNIP alleles. The screening process allowed us to zoom in from 160 candidate genes to eight genes that may contain functional rSNPs in their promoter regions.
|
|
| 32. |
|
|
| 33. |
- Milani, Lili, et al.
(författare)
-
DNA methylation for subtype classification and prediction of treatment outcome in patients with childhood acute lymphoblastic leukemia.
- 2010
-
Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 115:6, s. 1214-25
-
Tidskriftsartikel (refereegranskat)abstract
- Despite improvements in the prognosis of childhood acute lymphoblastic leukemia (ALL), subgroups of patients would benefit from alternative treatment approaches. Our aim was to identify genes with DNA methylation profiles that could identify such groups. We determined the methylation levels of 1320 CpG sites in regulatory regions of 416 genes in cells from 401 children diagnosed with ALL. Hierarchical clustering of 300 CpG sites distinguished between T-lineage ALL and B-cell precursor (BCP) ALL and between the main cytogenetic subtypes of BCP ALL. It also stratified patients with high hyperdiploidy and t(12;21) ALL into 2 subgroups with different probability of relapse. By using supervised learning, we constructed multivariate classifiers by external cross-validation procedures. We identified 40 genes that consistently contributed to accurate discrimination between the main subtypes of BCP ALL and gene sets that discriminated between subtypes of ALL and between ALL and controls in pairwise classification analyses. We also identified 20 individual genes with DNA methylation levels that predicted relapse of leukemia. Thus, methylation analysis should be explored as a method to improve stratification of ALL patients. The genes highlighted in our study are not enriched to specific pathways, but the gene expression levels are inversely correlated to the methylation levels.
|
|
| 34. |
- Milani, Lili, 1981-
(författare)
-
Gene Expression in Cancer Cells : Detection of Splice Variants, Allele-specific Expression and DNA Methylation
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The human genome sequencing project has provided a wealth of information on sequence variation between individuals. The surprisingly low number of genes in the human genome is compensated for by a complex regulation of gene expression. New methods are now being developed for the discovery and analysis of the regulatory regions of the genome to elucidate factors that affect both normal and disease-associated human genetic variation. In parallel with identification of DNA sequence variation, efforts are being made to unravel the next layer of information - epigenetic modifications of the genome. The studies in this thesis describe the application of methods for genotyping single nucleotide polymorphisms (SNPs) in DNA for the analysis of gene transcripts in cancer cells. We performed quantitative analysis of splice variants and screened for allele-specific gene expression (ASE) in cancer cells using the tag-microarray based minisequencing system. This analysis revealed transcript isoforms that were differentially spliced in leukemia cell lines and normal endothelial cell lines. We detected wide-spread allele-specific gene expression in cancer cells that were sensitive or resistant to anti-cancer drugs. In regulatory regions of the genes with ASE we identified putative regulatory SNPs. Using technology developed for large-scale SNP genotyping, we screened for ASE in an internationally unique collection of childhood acute lymphoblastic leukemia (ALL) samples. Analysis of DNA methylation in promoter regions of genes displaying ASE revealed genes, whose expression is regulated by allele-specific DNA methylation. For a subset of these genes we found a correlation between DNA methylation levels and probability of disease-free survival in ALL patients with different chromosomal aberrations. The methylation patterns that we identified constitute excellent candidate markers for subtyping of ALL patients and for stratification of ALL patients based on their probability of disease-free survival and response to drug treatment. The results of this study have increased our understanding of epigenetic changes in ALL cells and will hopefully help to design better treatment plans for the patients to avoid over-treatment and unnecessary side effects.
|
|
| 35. |
- Mukonzo, Jackson K, et al.
(författare)
-
A novel polymorphism in ABCB1 gene, CYP2B6*6 and sex predict single-dose efavirenz population pharmacokinetics in Ugandans.
- 2009
-
Ingår i: British journal of clinical pharmacology. - : Wiley. - 1365-2125 .- 0306-5251. ; 68:5, s. 690-9
-
Tidskriftsartikel (refereegranskat)abstract
- AIMS: Efavirenz exhibits pharmacokinetic variability causing varied clinical response. The aim was to develop an integrated population pharmacokinetic/pharmacogenetic model and investigate the impact of genetic variations, sex, demographic and biochemical variables on single-dose efavirenz pharmacokinetics among Ugandan subjects, using NONMEM. METHODS: Efavirenz plasma concentrations (n = 402) from 121 healthy subjects were quantified by high-performance liquid chromatography. Subjects were genotyped for 30 single nucleotide polymorphisms (SNPs), of which six were novel SNPs in CYP2B6, CYP3A5 and ABCB1. The efavirenz pharmacokinetics was described by a two-compartment model with zero- followed by first-order absorption. RESULTS: Apparent oral clearance (95% confidence interval) was 4 l h l(-1) (3.5, 4.5) in extensive metabolizers. In the final model, incorporating multiple covariates, statistical significance was found only for CYP2B6*6 and CYP2B6*11 on apparent oral clearance as well as ABCB1 (rs3842) on the relative bioavailability. Subjects homozygous for CYP2B6*6 (G516T, A785G) and *11 displayed 21 and 20% lower apparent oral clearance, respectively. Efavirenz relative bioavailability was 26% higher in subjects homozygous for ABCB1 (rs3842). The apparent peripheral volume of distribution was twofold higher in women compared with men. CONCLUSIONS: The model identified the four factors CYP2B6*6, CYP2B6*11, a novel variant allele in ABCB1 (rs3842) and sex as major predictors of efavirenz plasma exposure in a healthy Ugandan population after single-dose administration. Use of mixed-effects modelling allowed the analysis and integration of multiple pharmacogenetic and demographic covariates in a pharmacokinetic population model.
|
|
| 36. |
- Nethander, Maria, 1980, et al.
(författare)
-
Assessment of the genetic and clinical determinants of hip fracture risk: Genome-wide association and Mendelian randomization study.
- 2022
-
Ingår i: Cell reports. Medicine. - : Elsevier BV. - 2666-3791. ; 3:10
-
Tidskriftsartikel (refereegranskat)abstract
- Hip fracture is the clinically most important fracture, but the genetic architecture of hip fracture is unclear. Here, we perform a large-scale hip fracture genome-wide association study meta-analysis and Mendelian randomization study using five cohorts from European biobanks. The results show that five genetic signals associate with hip fractures. Among these, one signal associates with falls, but not with bone mineral density (BMD), while four signals are in loci known to be involved in bone biology. Mendelian randomization analyses demonstrate a strong causal effect of decreased femoral neck BMD and moderate causal effects of Alzheimer's disease and having ever smoked regularly on risk of hip fractures. The substantial causal effect of decreased femoral neck BMD on hip fractures in both young and old subjects and in both men and women supports the use of change in femoral neck BMD as a surrogate outcome for hip fractures in clinical trials.
|
|
| 37. |
- Nordlund, Jessica, et al.
(författare)
-
DNA Methylation Analysis of Bone Marrow Cells at Diagnosis of Acute Lymphoblastic Leukemia and at Remission
- 2012
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:4, s. e34513-
-
Tidskriftsartikel (refereegranskat)abstract
- To detect genes with CpG sites that display methylation patterns that are characteristic of acute lymphoblastic leukemia (ALL) cells, we compared the methylation patterns of cells taken at diagnosis from 20 patients with pediatric ALL to the methylation patterns in mononuclear cells from bone marrow of the same patients during remission and in non-leukemic control cells from bone marrow or blood. Using a custom-designed assay, we measured the methylation levels of 1,320 CpG sites in regulatory regions of 413 genes that were analyzed because they display allele-specific gene expression (ASE) in ALL cells. The rationale for our selection of CpG sites was that ASE could be the result of allele-specific methylation in the promoter regions of the genes. We found that the ALL cells had methylation profiles that allowed distinction between ALL cells and control cells. Using stringent criteria for calling differential methylation, we identified 28 CpG sites in 24 genes with recurrent differences in their methylation levels between ALL cells and control cells. Twenty of the differentially methylated genes were hypermethylated in the ALL cells, and as many as nine of them (AMICA1, CPNE7, CR1, DBC1, EYA4, LGALS8, RYR3, UQCRFS1, WDR35) have functions in cell signaling and/or apoptosis. The methylation levels of a subset of the genes were consistent with an inverse relationship with the mRNA expression levels in a large number of ALL cells from published data sets, supporting a potential biological effect of the methylation signatures and their application for diagnostic purposes.
|
|
| 38. |
- Parmar, Priyanka, et al.
(författare)
-
Association of maternal prenatal smoking GFI1-locus and cardiometabolic phenotypes in 18,212 adults
- 2018
-
Ingår i: EBioMedicine. - : Elsevier BV. - 2352-3964. ; 38, s. 206-216
-
Tidskriftsartikel (refereegranskat)abstract
- Background: DNA methylation at the GFI1-locus has been repeatedly associated with exposure to smoking from the foetal period onwards. We explored whether DNA methylation may be a mechanism that links exposure to maternal prenatal smoking with offspring's adult cardio-metabolic health. Methods: We meta-analysed the association between DNA methylation at GFI1-locus with maternal prenatal smoking, adult own smoking, and cardio-metabolic phenotypes in 22 population-based studies from Europe, Australia, and USA (n= 18,212). DNA methylation at the GFI1-locus was measured in whole-blood. Multivariable regression models were fitted to examine its association with exposure to prenatal and own adult smoking. DNA methylation levels were analysed in relation to body mass index (BMI), waist circumference (WC), fasting glucose (FG), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), diastolic, and systolic blood pressure (BP). Findings: Lower DNA methylation at three out of eight GFI1-CpGs was associated with exposure to maternal prenatal smoking, whereas, all eight CpGs were associated with adult own smoking. Lower DNA methylation at cg14179389, the strongest maternal prenatal smoking locus, was associated with increased WC and BP when adjusted for sex, age, and adult smoking with Bonferroni-corrected P < 0.012. In contrast, lower DNA methylation at cg09935388, the strongest adult own smoking locus, was associated with decreased BMI, WC, and BP (adjusted 1 x 10(-7) < P < 0.01). Similarly, lower DNA methylation at cg12876356, cg18316974, cg09662411, and cg18146737 was associated with decreased BMI and WC (5 x 10(-8) < P < 0.001). Lower DNA methylation at all the CpGs was consistently associated with higher TG levels. Interpretation: Epigenetic changes at the GFI1 were linked to smoking exposure in-utero/in-adulthood and robustly associated with cardio-metabolic risk factors. Fund: European Union's Horizon 2020 research and innovation programme under grant agreement no. 633595 DynaHEALTH.
|
|
| 39. |
- Reisberg, Sulev, et al.
(författare)
-
Translating genotype data of 44,000 biobank participants into clinical pharmacogenetic recommendations : challenges and solutions
- 2019
-
Ingår i: Genetics in Medicine. - : NATURE PUBLISHING GROUP. - 1098-3600 .- 1530-0366. ; 21:6, s. 1345-1354
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: Biomedical databases combining electronic medical records and phenotypic and genomic data constitute a powerful resource for the personalization of treatment. To leverage the wealth of information provided, algorithms are required that systematically translate the contained information into treatment recommendations based on existing genotype-phenotype associations. Methods: We developed and tested algorithms for translation of preexisting genotype data of over 44,000 participants of the Estonian biobank into pharmacogenetic recommendations. We compared the results obtained by genome sequencing, exome sequencing, and genotyping using microarrays, and evaluated the impact of pharmacogenetic reporting based on drug prescription statistics in the Nordic countries and Estonia. Results: Our most striking result was that the performance of genotyping arrays is similar to that of genome sequencing, whereas exome sequencing is not suitable for pharmacogenetic predictions. Interestingly, 99.8% of all assessed individuals had a genotype associated with increased risks to at least one medication, and thereby the implementation of pharmacogenetic recommendations based on genotyping affects at least 50 daily drug doses per 1000 inhabitants. Conclusion: We find that microarrays are a cost-effective solution for creating preemptive pharmacogenetic reports, and with slight modifications, existing databases can be applied for automated pharmacogenetic decision support for clinicians.
|
|
| 40. |
- Ried, Janina S., et al.
(författare)
-
A principal component meta-analysis on multiple anthropometric traits identifies novel loci for body shape
- 2016
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways.
|
|
