| 1. |
- Edlundh-Rose, Esther, et al.
(författare)
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Gene expression analysis of human epidermal keratinocytes after N-acetyl L-cysteine treatment demonstrates cell cycle arrest and increased differentiation
- 2005
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Ingår i: Pathobiology (Basel). - : S. Karger AG. - 1015-2008 .- 1423-0291. ; 72:4, s. 203-212
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Several cancer prevention programmes have previously been executed using treatment of antioxidant compounds. The antioxidant N-acetyl L-cysteine (NAC), a membrane-permeable aminothiol, is a sulfhydryl reductant reducing oxidised glutathione, as well as being a precursor of intracellular cysteine and glutathione. A previous report based on the cellular response to NAC treatment showed that NAC induced a 10-fold more rapid differentiation in normal primary keratinocytes as well as a reversion of a colon carcinoma cell line from neoplastic proliferation to apical-basolateral differentiation. In order to investigate molecular events underlying the changes in proliferation and differentiation induced by NAC treatment, we performed global gene expression analysis of normal human epidermal keratinocytes in a time series. Methods: Treated samples were compared to untreated samples through a reference design using a spotted cDNA array comprising approximately 30,000 features. B statistics was used to identify differentially expressed genes, and RT-PCR of a selected set of genes was performed to verify differential expression. Results: The number of differentially expressed genes increased over time, starting with 0 at 30 min, 73 at 3 h and increasing to 952 genes at 48 h. Results of the expression analysis showed arrest of the cell cycle and an upregulation of cytoskeletal reorganisation, implicating increased differentiation. A comparison to gene ontology groups indicated downregulation of a large number of genes involved in cell proliferation and regulation of the cell cycle. Conclusions: A significant fraction of the differentially expressed genes could be classified according to their role in the differentiation process, demonstrating that NAC regulates the conversion from proliferation to differentiation at a transcriptional level.
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| 2. |
- Green, Henrik, et al.
(författare)
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Using Whole-Exome Sequencing to Identify Genetic Markers for Carboplatin and Gemcitabine-Induced Toxicities
- 2016
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Ingår i: Clinical Cancer Research. - : AMER ASSOC CANCER RESEARCH. - 1078-0432 .- 1557-3265. ; 22:2, s. 366-373
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Chemotherapies are associated with significant interindividual variability in therapeutic effect and adverse drug reactions. In lung cancer, the use of gemcitabine and carboplatin induces grade 3 or 4 myelosuppression in about a quarter of the patients, while an equal fraction of patients is basically unaffected in terms of myelosuppressive side effects. We therefore set out to identify genetic markers for gemcitabine/carboplatin-induced myelosuppression. Experimental Design: We exome sequenced 32 patients that suffered extremely high neutropenia and thrombocytopenia (grade 3 or 4 after first chemotherapy cycle) or were virtually unaffected (grade 0 or 1). The genetic differences/polymorphism between the groups were compared using six different bioinformatics strategies: (i) whole-exome nonsynonymous single-nucleotide variants association analysis, (ii) deviation from Hardy-Weinberg equilibrium, (iii) analysis of genes selected by a priori biologic knowledge, (iv) analysis of genes selected from gene expression meta-analysis of toxicity datasets, (v) Ingenuity Pathway Analysis, and (vi) FunCoup network enrichment analysis. Results: A total of 53 genetic variants that differed among these groups were validated in an additional 291 patients and were correlated to the patients myelosuppression. In the validation, we identified rs1453542 in OR4D6 (P = 0.0008; OR, 5.2; 95% CI, 1.8-18) as a marker for gemcitabine/carboplatin-induced neutropenia and rs5925720 in DDX53 (P = 0.0015; OR, 0.36; 95% CI, 0.17-0.71) as a marker for thrombocytopenia. Patients homozygous for the minor allele of rs1453542 had a higher risk of neutropenia, and for rs5925720 the minor allele was associated with a lower risk for thrombocytopenia. Conclusions: We have identified two new genetic markers with the potential to predict myelosuppression induced by gemcitabine/ carboplatin chemotherapy. (C)2015 AACR.
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| 3. |
- Gustafsson, Anna, et al.
(författare)
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Global gene expression analysis in time series following N-acetyl L-cysteine induced epithelial differentiation of human normal and cancer cells in vitro
- 2005
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Ingår i: BMC Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 5, s. 75-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cancer prevention trials using different types of antioxidant supplements have been carried out at several occasions and one of the investigated compounds has been the antioxidant N-acetyl-L-cysteine (NAC). Studies at the cellular level have previously demonstrated that a single supplementation of NAC induces a ten-fold more rapid differentiation in normal primary human keratinocytes as well as a reversion of a colon carcinoma cell line from neoplastic proliferation to apical-basolateral differentiation [1]. The investigated cells showed an early change in the organization of the cytoskeleton, several newly established adherens junctions with E-cadherin/β-catenin complexes and increased focal adhesions, all features characterizing the differentiation process. Methods: In order to investigate the molecular mechanisms underlying the proliferation arrest and accelerated differentiation induced by NAC treatment of NHEK and Caco-2 cells in vitro, we performed global gene expression analysis of NAC treated cells in a time series (1, 12 and 24 hours post NAC treatment) using the Affymetrix GeneChip™ Human Genome U95Av2 chip, which contains approximately 12,000 previously characterized sequences. The treated samples were compared to the corresponding untreated culture at the same time point. Results: Microarray data analysis revealed an increasing number of differentially expressed transcripts over time upon NAC treatment. The early response (1 hour) was transient, while a constitutive trend was commonly found among genes differentially regulated at later time points (12 and 24 hours). Connections to the induction of differentiation and inhibition of growth were identified for a majority of up- and down-regulated genes. All of the observed transcriptional changes, except for seven genes, were unique to either cell line. Only one gene, ID-1, was mutually regulated at 1 hour post treatment and might represent a common mediator of early NAC action. The detection of several genes that previously have been identified as stimulated or repressed during the differentiation of NHEK and Caco-2 provided validation of results. In addition, real-time kinetic PCR analysis of selected genes also verified the differential regulation as identified by the microarray platform. Conclusion: NAC induces a limited and transient early response followed by a more consistent and extensively different expression at later time points in both the normal and cancer cell lines investigated. The responses are largely related to inhibition of proliferation and stimulation of differentiation in both cell types but are almost completely lineage specific. ID-1 is indicated as an early mediator of NAC action.
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| 4. |
- Hasmats, Johanna, et al.
(författare)
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Identification of candidate SNPs for drug induced toxicity from differentially expressed genes in associated tissues
- 2012
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Ingår i: Gene. - : Elsevier. - 0378-1119 .- 1879-0038. ; 506:1, s. 62-68
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Tidskriftsartikel (refereegranskat)abstract
- The growing collection of publicly available high-throughput data provides an invaluable resource for generating preliminary in silico data in support of novel hypotheses. In this study we used a cross-dataset meta-analysis strategy to identify novel candidate genes and genetic variations relevant to paclitaxel/carboplatin-induced myelosuppression and neuropathy. We identified genes affected by drug exposure and present in tissues associated with toxicity. From ten top-ranked genes 42 non-synonymous single nucleotide polymorphisms (SNPs) were identified in silico and genotyped in 94 cancer patients treated with carboplatin/paclitaxel. We observed variations in 11 SNPs, of which seven were present in a sufficient frequency for statistical evaluation. Of these seven SNPs. three were present in ABCA1 and ATM, and showed significant or borderline significant association with either myelosuppression or neuropathy. The strikingly high number of associations between genotype and clinically observed toxicity provides support for our data-driven computations strategy to identify biomarkers for drug toxicity.
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| 5. |
- Hasmats, Johanna, et al.
(författare)
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Using whole exome sequencing to identify genetic candidates for carboplatin and gemcitabine induced toxicities
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Chemotherapies are associated with significant inter-individual variability in therapeutic effect and adverse drug reactions. In lung cancer the use of gemcitabine and carboplatin induces grade 3-4 myelosuppression in about ¼ of the patients while an equal fraction of patients are basically unaffected in terms of myelosuppressive side effects. We therefore set out to try to identify genetic markers for gemcitabine / carboplatin induced myelosuppression. We selected 32 patients that suffered extremely high neutropenia and thrombocytopenia (grade 3 or 4 after first chemotherapy cycle) or were virtually unaffected (grade 0-1 after the first chemotherapy cycle) by the chemotherapy out of 243 lung cancer patients treated with gemcitabine / carboplatin. These patients were exome sequenced and their genetic differences compared using six different bioinformatic strategies; whole exome non-synonymous SNV association analysis, deviation from Hardy-Weinberg equilibrium, analysis of genes selected by a priori biological knowledge, analysis of genes selected from gene expression meta-analysis of toxicity data sets, Ingenuity pathway analysis and FunCoup network enrichment analysis. All patients were successfully sequenced and 5000-7000 non-synonymous single nucleotide variants were identified in each patient. PI3 (elastase specific inhibitor in neutrophils) showed the strongest association in the single SNV analysis (nominal p=0.0005). Further, variants within IL37, an inhibitor of the innate immune system, and CSAG1, a tumor antigen, differed among the two patient groups and appeared among the top hits in several of the performed analysis, indicating that the approach identifies genetic variants associated with the immune system and tumor differentiation, which might be important for the sensitivity to chemotherapeutic agents. However, the associations reported here are in a need of replication before clinical interpretations can be made.
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| 6. |
- Kivi, Marten, et al.
(författare)
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Helicobacter pylori genome variability in a framework of familial transmission
- 2007
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 7, s. 54-
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Tidskriftsartikel (refereegranskat)abstract
- Background: Helicobacter pylori infection is exceptionally prevalent and is considered to be acquired primarily early in life through person-to-person transmission within the family. H. pylori is a genetically diverse bacterial species, which may facilitate adaptation to new hosts and persistence for decades. The present study aimed to explore the genetic diversity of clonal isolates from a mother and her three children in order to shed light on H. pylori transmission and host adaptation. Results: Two different H. pylori strains and strain variants were identified in the family members by PCR-based molecular typing and sequencing of five loci. Genome diversity was further assessed for 15 isolates by comparative microarray hybridizations. The microarray consisted of 1,745 oligonucleotides representing the genes of two previously sequenced H. pylori strains. The microarray analysis detected a limited mean number (+/- standard error) of divergent genes between clonal isolates from the same and different individuals (1 +/- 0.4, 0.1%, and 3 +/- 0.3, 0.2%, respectively). There was considerable variability between the two different strains in the family members (147 +/- 4, 8%) and for all isolates relative to the two sequenced reference strains (314 +/- 16, 18%). The diversity between different strains was associated with gene functional classes related to DNA metabolism and the cell envelope. Conclusion: The present data from clonal H. pylori isolates of family members do not support that transmission and host adaptation are associated with substantial sequence diversity in the bacterial genome. However, important phenotypic modifications may be determined by additional genetic mechanisms, such as phase-variation. Our findings can aid further exploration of H. pylori genetic diversity and adaptation.
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| 7. |
- Kupershmidt, Ilya, et al.
(författare)
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Ontology-Based Meta-Analysis of Global Collections of High-Throughput Public Data
- 2010
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:9, s. e13066-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The investigation of the interconnections between the molecular and genetic events that govern biological systems is essential if we are to understand the development of disease and design effective novel treatments. Microarray and next-generation sequencing technologies have the potential to provide this information. However, taking full advantage of these approaches requires that biological connections be made across large quantities of highly heterogeneous genomic datasets. Leveraging the increasingly huge quantities of genomic data in the public domain is fast becoming one of the key challenges in the research community today. Methodology/Results: We have developed a novel data mining framework that enables researchers to use this growing collection of public high-throughput data to investigate any set of genes or proteins. The connectivity between molecular states across thousands of heterogeneous datasets from microarrays and other genomic platforms is determined through a combination of rank-based enrichment statistics, meta-analyses, and biomedical ontologies. We address data quality concerns through dataset replication and meta-analysis and ensure that the majority of the findings are derived using multiple lines of evidence. As an example of our strategy and the utility of this framework, we apply our data mining approach to explore the biology of brown fat within the context of the thousands of publicly available gene expression datasets. Conclusions: Our work presents a practical strategy for organizing, mining, and correlating global collections of large-scale genomic data to explore normal and disease biology. Using a hypothesis-free approach, we demonstrate how a data-driven analysis across very large collections of genomic data can reveal novel discoveries and evidence to support existing hypothesis.
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