scholarly journals An Integrated Approach for RNA-seq Data Normalization

2016 ◽  
Vol 15 ◽  
pp. CIN.S39781 ◽  
Author(s):  
Shengping Yang ◽  
Donald E. Mercante ◽  
Kun Zhang ◽  
Zhide Fang
Keyword(s):  
Gene Expression ◽  
Dna Sequences ◽  
Copy Number ◽  
Differentially Expressed Gene ◽  
Integrated Approach ◽  
Gene Profiling ◽  
Data Normalization ◽  
Rna Seq ◽  
Dna Copy Number ◽  
Copy Number Changes

Background DNA copy number alteration is common in many cancers. Studies have shown that insertion or deletion of DNA sequences can directly alter gene expression, and significant correlation exists between DNA copy number and gene expression. Data normalization is a critical step in the analysis of gene expression generated by RNA-seq technology. Successful normalization reduces/removes unwanted nonbiological variations in the data, while keeping meaningful information intact. However, as far as we know, no attempt has been made to adjust for the variation due to DNA copy number changes in RNA-seq data normalization. Results In this article, we propose an integrated approach for RNA-seq data normalization. Comparisons show that the proposed normalization can improve power for downstream differentially expressed gene detection and generate more biologically meaningful results in gene profiling. In addition, our findings show that due to the effects of copy number changes, some housekeeping genes are not always suitable internal controls for studying gene expression. Conclusions Using information from DNA copy number, integrated approach is successful in reducing noises due to both biological and nonbiological causes in RNA-seq data, thus increasing the accuracy of gene profiling.

scholarly journals Genes with Relevance for Early to Late Progression of Colon Carcinoma Based on Combined Genomic and Transcriptomic Information from the Same Patients

2010 ◽  
Vol 9 ◽  
pp. CIN.S4545 ◽  
Author(s):  
Kristina K. Lagerstedt ◽  
Erik Kristiansson ◽  
Christina Lönnroth ◽  
Marianne Andersson ◽  
Britt-Marie IresjÖ ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colon Cancer ◽  
Tumor Progression ◽  
Cancer Progression ◽  
Copy Number ◽  
Dna Copy Number ◽  
Colon Cancer Progression ◽  
Dna Alterations ◽  
Copy Number Changes ◽  
Dukes C

Background Genetic and epigenetic alterations in colorectal cancer are numerous. However, it is difficult to judge whether such changes are primary or secondary to the appearance and progression of tumors. Therefore, the aim of the present study was to identify altered DNA regions with significant covariation to transcription alterations along colon cancer progression. Methods Tumor and normal colon tissue were obtained at primary operations from 24 patients selected by chance. DNA, RNA and microRNAs were extracted from the same biopsy material in all individuals and analyzed by oligo-nucleotide array-based comparative genomic hybridization (CGH), mRNA- and microRNA oligo-arrays. Statistical analyses were performed to assess statistical interactions (correlations, co-variations) between DNA copy number changes and significant alterations in gene and microRNA expression using appropriate parametric and non-parametric statistics. Results Main DNA alterations were located on chromosome 7, 8, 13 and 20. Tumor DNA copy number gain increased with tumor progression, significantly related to increased gene expression. Copy number loss was not observed in Dukes A tumors. There was no significant relationship between expressed genes and tumor progression across Dukes A–D tumors; and no relationship between tumor stage and the number of microRNAs with significantly altered expression. Interaction analyses identified overall 41 genes, which discriminated early Dukes A plus B tumors from late Dukes C plus D tumor; 28 of these genes remained with correlations between genomic and transcriptomic alterations in Dukes C plus D tumors and 17 in Dukes D. One microRNA (microR-663) showed interactions with DNA alterations in all Dukes A-D tumors. Conclusions Our modeling confirms that colon cancer progression is related to genomic instability and altered gene expression. However, early invasive tumor growth seemed rather related to transcriptomic alterations, where changes in microRNA may be an early phenomenon, and less to DNA copy number changes.

scholarly journals Joint single cell DNA-Seq and RNA-Seq of cancer reveals subclonal signatures of genomic instability and gene expression

2018 ◽  
Author(s):  
Noemi Andor ◽  
Billy T. Lau ◽  
Claudia Catalanotti ◽  
Vijay Kumar ◽  
Anuja Sathe ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Copy Number ◽  
Gastric Cancer Cell ◽  
Tumor Evolution ◽  
Rna Seq ◽  
Cancer Heterogeneity ◽  
Gastric Cancer Cell Lines ◽  
Joint Study ◽  
Copy Number Changes

ABSTRACTSequencing the genomes of individual cancer cells provides the highest resolution of intratumoral heterogeneity. To enable high throughput single cell DNA-Seq across thousands of individual cells per sample, we developed a droplet-based, automated partitioning technology for whole genome sequencing. We applied this approach on a set of gastric cancer cell lines and a primary gastric tumor. In parallel, we conducted a separate single cell RNA-Seq analysis on these same cancers and used copy number to compare results. This joint study, covering thousands of single cell genomes and transcriptomes, revealed extensive cellular diversity based on distinct copy number changes, numerous subclonal populations and in the case of the primary tumor, subclonal gene expression signatures. We found genomic evidence of positive selection – where the percentage of replicating cells per clone is higher than expected – indicating ongoing tumor evolution. Our study demonstrates that joining single cell genomic DNA and transcriptomic features provides novel insights into cancer heterogeneity and biology.SIGNIFICANCEWe conducted a massively parallel DNA sequencing analysis on a set of gastric cancer cell lines and a primary gastric tumor in combination with a joint single cell RNA-Seq analysis. This joint study, covering thousands of single cell genomes and transcriptomes, revealed extensive cellular diversity based on distinct copy number changes, numerous subclonal populations and in the case of the primary tumor, subclonal gene expression signatures. We found genomic evidence of positive selection where the percentage of replicating cells per clone is higher than expected indicating ongoing tumor evolution. Our study demonstrates that combining single cell genomic DNA and transcriptomic features provides novel insights into cancer heterogeneity and biology.

AML/MDS with 11q/MLLamplification show characteristic gene expression signature and interplay of DNA copy number changes

2009 ◽  
Vol 48 (6) ◽  
pp. 510-520 ◽  
Author(s):  
Andrea Zatkova ◽  
Sylvia Merk ◽  
Melanie Wendehack ◽  
Martin Bilban ◽  
Eva Maria Muzik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Copy Number ◽  
Gene Expression Signature ◽  
Dna Copy Number ◽  
Expression Signature ◽  
Copy Number Changes

Comparison of gene expression and DNA copy number changes in a murine model of lung cancer

2005 ◽  
Vol 45 (4) ◽  
pp. 338-348 ◽  
Author(s):  
Alejandro Sweet-Cordero ◽  
George C. Tseng ◽  
Han You ◽  
Margaret Douglass ◽  
Bing Huey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lung Cancer ◽  
Murine Model ◽  
Copy Number ◽  
Dna Copy Number ◽  
Copy Number Changes

Transcriptional profiling of iPSC-derived neurons with reciprocal monogenic CNV in 3p26.3 region

2020 ◽  
pp. 10-11
Author(s):  
М.Е. Лопаткина ◽  
В.С. Фишман ◽  
М.М. Гридина ◽  
Н.А. Скрябин ◽  
Т.В. Никитина ◽  
...  
Keyword(s):  
Gene Expression ◽  
Copy Number ◽  
System Development ◽  
Transcriptional Profiling ◽  
Global Gene Expression ◽  
Nervous System Development ◽  
Number Variation ◽  
The Central Nervous System ◽  
Cntn6 Gene ◽  
Copy Number Changes

Проведен анализ генной экспрессии в нейронах, дифференцированных из индуцированных плюрипотентных стволовых клеток пациентов с идиопатическими интеллектуальными нарушениями и реципрокными хромосомными мутациями в регионе 3p26.3, затрагивающими единственный ген CNTN6. Для нейронов с различным типом хромосомных аберраций была показана глобальная дисрегуляция генной экспрессии. В нейронах с вариациями числа копий гена CNTN6 была снижена экспрессия генов, продукты которых вовлечены в процессы развития центральной нервной системы. The gene expression analysis of iPSC-derived neurons, obtained from patients with idiopathic intellectual disability and reciprocal microdeletion and microduplication in 3p26.3 region affecting the single CNTN6 gene was performed. The global gene expression dysregulation was demonstrated for cells with CNTN6 copy number variation. Gene expression in neurons with CNTN6 copy number changes was downregulated for genes, whose products are involved in the central nervous system development.

scholarly journals Genomic Adaption and Mutational Patterns in a HaCaT Subline Resistant to Alkylating Agents and Ionizing Radiation

2021 ◽  
Vol 22 (3) ◽  
pp. 1146
Author(s):  
Reinhard Ullmann ◽  
Benjamin Valentin Becker ◽  
Simone Rothmiller ◽  
Annette Schmidt ◽  
Horst Thiermann ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Line ◽  
Copy Number ◽  
Resistant Cell ◽  
Resistant Cell Line ◽  
Chromosomal Translocations ◽  
Dna Copy Number ◽  
Mutational Signatures ◽  
Copy Number Changes ◽  
And Oxidative Stress

Sulfur mustard (SM) is a chemical warfare agent that can damage DNA via alkylation and oxidative stress. Because of its genotoxicity, SM is cancerogenic and the progenitor of many chemotherapeutics. Previously, we developed an SM-resistant cell line via chronic exposure of the popular keratinocyte cell line HaCaT to increasing doses of SM over a period of 40 months. In this study, we compared the genomic landscape of the SM-resistant cell line HaCaT/SM to its sensitive parental line HaCaT in order to gain insights into genetic changes associated with continuous alkylation and oxidative stress. We established chromosome numbers by cytogenetics, analyzed DNA copy number changes by means of array Comparative Genomic Hybridization (array CGH), employed the genome-wide chromosome conformation capture technique Hi-C to detect chromosomal translocations, and derived mutational signatures by whole-genome sequencing. We observed that chronic SM exposure eliminated the initially prevailing hypotetraploid cell population in favor of a hyperdiploid one, which contrasts with previous observations that link polyploidization to increased tolerance and adaptability toward genotoxic stress. Furthermore, we observed an accumulation of chromosomal translocations, frequently flanked by DNA copy number changes, which indicates a high rate of DNA double-strand breaks and their misrepair. HaCaT/SM-specific single-nucleotide variants showed enrichment of C > A and T > A transversions and a lower rate of deaminated cytosines in the CpG dinucleotide context. Given the frequent use of HaCaT in toxicology, this study provides a valuable data source with respect to the original genotype of HaCaT and the mutational signatures associated with chronic alkylation and oxidative stress.

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