Identification of novel gene amplification events in breast cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE16619 | GEO | 2009/09/16
SECONDARY ACCESSION(S): PRJNA116261
REPOSITORIES: GEO
Similar Datasets
Project description:To identify novel gene amplification events that may contribute to breast cancer progression, we examined copy number variation in 161 primary breast cancer samples using the Affymetrix 250K_Nsp and 250K_Sty microarrays or the Affymetrix SNP5.0 microarray. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from primary breast cancer samples. Copy number variations were determined from probeset signal intensities.
2010-06-23 | E-GEOD-16619 | biostudies-arrayexpress
Project description:Heteroresistance in bacteria describes a subpopulational phenomenon of transient antibiotic resistance variation among cells of a generally susceptible population. Here, we investigated the molecular mechanisms and phenotypic characteristics underlying heteroresistance to ceftazidime (CAZ) in a clinical Enterobacter cloacae complex strain (ECC). We identified a plasmid-borne gene duplication-amplification (GDA) event of a region harboring an ampC gene encoding a β-lactamase blaDHA-1 as the key determinant of heteroresistance. Individual colonies exhibited variations in the copy number of the genes resulting in resistance level variation which correlated with growth onset (lag times) and growth rates in the presence of CAZ, analysed in linear models. GDA copy number heterogeneity occurred within single resistant colonies, demonstrating heterogeneity of GDA on the single-cell level. The interdependence between GDA, lag time and antibiotic treatment and the strong plasticity underlying heteroresistance underlines the high risk for misdetection of antimicrobial heteroresistance and subsequent treatment failure.
2024-10-17 | PXD056728 | Pride
Project description:DNA amplification, particularly of chromosomes 8 and 11, occurs frequently in breast cancer and is a key factor in tumorigenesis, often associated with poor prognosis. The mechanisms involved in the amplification of these regions are not fully understood. Studies from model systems have demonstrated that palindrome formation can be an early step in DNA amplification, most notably seen in the breakage-fusion-bridge (BFB) cycle. Therefore, palindromes might be associated with gene amplicons in breast cancer. To address this possibility, we coupled high-resolution palindrome profiling by the Genome-wide Analysis of Palindrome Formation (GAPF) assay with genome-wide copy-number analyses on a set of breast cancer cell lines and primary tumors to spatially associate palindromes and copy-number gains. We identified GAPF-positive regions distributed non-randomly throughout cell line and tumor genomes, often in clusters and associated with copy-number gains. Commonly amplified regions in breast cancer, chromosomes 8q and 11q, had GAPF-positive regions flanking and throughout the copy-number gains. We also identified amplification-associated GAPF-positive regions at similar locations in subsets of breast cancers with similar characteristics (e.g., ERBB2 amplification). These shared positive regions offer the potential to evaluate the utility of palindromes as prognostic markers, particularly in premalignant breast lesions. Our results implicate palindrome formation in the amplification of regions with key roles in breast tumorigenesis, particularly in subsets of breast cancers.
2011-06-13 | GSE29876 | GEO
Project description:Genome-wide screening for regions of genetic gains and losses on nine prostate cancer cell lines (PC3, DU145, LNCaP, CWR22, and derived sublines) was carried out using comparative genomic hybridization on a 35 K longmer oligonucleotide microarray (arrayCGH). Compared to conventional chromosomal CGH more deletions and small regions of gains, particularly in pericentromeric regions and regions next to the telomers, were detected. As a proof for the high-resolution of arrayCGH we further analyzed a small amplification unit of 1.7 MB at 9p13.3, which was found in CWR22 and CWR22-Rv1. Increased copy number was confirmed by fluorescence in situ hybridization using the BAC clone RP11-165H19 from the amplified region comprising the two genes interleukin 11 receptor alpha (IL11-RA) and dynactin 3 (DCTN3). Using quantitative real time PCR (qPCR) we could demonstrate that IL11-RA is the gene with the highest copy number gain in the cell lines compared to DCTN3 suggesting IL11-RA to be the amplification target. Screening of 20 primary prostate carcinomas by qPCR revealed a high frequency of IL11-RA copy number gain in 75% of the tumors analyzed. Gain of DCTN3 was only found in two cases together with a gain of IL11-RA. Thus, IL11-RA is a frequently amplified gene in prostate cancer with amplification being supposed to be one mechanism of IL11-RA overexpression in this tumor type. Keywords: comparative genomic hybridization
2007-10-23 | GSE7376 | GEO
Project description:<p>DNA Inverted Repeats as an At-risk Motif for Palindromic Gene Amplificatio defines oncogene amplification that is configured as a series of inverted duplications (palindromic gene amplification). There are several, recurrently amplified oncogenes throughout the human genome. However, it remains unclear whether this recurrent amplification is solely a manifestation of increased fitness resulting from random amplification mechanisms, or if genomic locus-specific amplification mechanism plays a role. </p> <p>In this study, we show that the ERBB2 oncogene at 17q12 is susceptible to palindromic gene amplification in HER2-positive breast tumors. We investigated eight tumors in this study, of which five tumors were HER2-positive, and three tumors were HER2-negative. HER2-status was determined by clinical FISH tests. We applied three genomic approaches to investigate the amplification mechanism: (1) copy number analysis by array-CGH on the Affymetrix SNP6.0 platform (8 files), (2) sequencing of DNA libraries enriched with tumor-derived palindromic DNA (Genome-wide Analysis of Palindrome Formation, GAPF-seq) (8 files) and (3) unbiased whole genome sequencing (WGS) (1 file). These molecular data is made available in the dbGaP. </p> <p>Genomic studies using tumor DNA was approved under the Internal Institutional Review Board at the Cleveland Clinic (IRB07-136: EXEMPT: Chromosome Breakage and DNA Palindrome Formation). Specimens were obtained and methods were carried out under the auspices of IRB 7881 (Evaluation of Genetic and Molecular Markers in Patients with Breast Cancer). All patients consented to allow their cancer specimens to be used by researchers in an anonymized fashion. The consent form indicates that publication will take place without identifiers to protect the identity of any specific individual.</p> <p>We observed significant and enrichment of palindromic DNA within amplified ERBB2 genomic segments in four out of five HER2-positive tumors. None of three HER2-negative tumors showed such enrichment. Palindromic DNA was particularly enriched at amplification peaks and boundaries between amplified and normal copy-number regions. Thus, palindromic gene amplification shaped the amplified ERBB2 locus. The moderate enrichment of palindromic DNA throughout the amplified segments leads us to propose that the ERBB2 locus is amplified through a mechanism that repeatedly generates palindromic DNA, such as Breakage-Fusion-Bridge cycles. Our results reveal a potential interaction between local genomic environments and gene amplification mechanisms. </p> <p>This study is published under the title "Palindromic amplification of the ERBB2 oncogene in primary HER2-positive breast tumors" <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=28211519" target="_blank">(PMID:28211519)</a>. </p>
| phs001261 | dbGaP
Project description:Genomic DNA copy number alterations are key genetic events in the development and progression of human cancers. Here we report a genome-wide microarray comparative genomic hybridization (array CGH) analysis of DNA copy number variation in a series of primary human breast tumors. We have profiled DNA copy number alteration across 6,691 mapped human genes, in 44 predominantly advanced, primary breast tumors and 10 breast cancer cell lines. While the overall patterns of DNA amplification and deletion corroborate previous cytogenetic studies, the high-resolution (gene-by-gene) mapping of amplicon boundaries and the quantitative analysis of amplicon shape provide significant improvement in the localization of candidate oncogenes. Parallel microarray measurements of mRNA levels reveal the remarkable degree to which variation in gene copy number contributes to variation in gene expression in tumor cells. Specifically, we find that 62% of highly amplified genes show moderately or highly elevated expression, that DNA copy number influences gene expression across a wide range of DNA copy number alterations (deletion, low-, mid- and high-level amplification), that on average, a 2-fold change in DNA copy number is associated with a corresponding 1.5-fold change in mRNA levels, and that overall, at least 12% of all the variation in gene expression among the breast tumors is directly attributable to underlying variation in gene copy number. These findings provide evidence that widespread DNA copy number alteration can lead directly to global deregulation of gene expression, which may contribute to the development or progression of cancer. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set, arrayCGH
2005-09-10 | GSE3281 | GEO
Project description:EZH2 is shown to be involved in regulation of DNA damage repair which may contribute to development of breast tumor initiating cells. To identify genomic aberrations regulated by EZH2 expression, we performed genome wide copy number variation analysis in breast tumor initiating cells expressing EZH2 compared to the vector control. This finding suggests EZH2 contributes to oncogenic amplification in breast tumor initiating cells. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from primary breast tumor initiating cells infected with EZH2 or Vector control constructs Copy number variation analysis of Affymetrix SNP 6.0 arrays was performed and compared between EZH2 and Vector control infected groups
2010-09-17 | E-GEOD-24144 | biostudies-arrayexpress
Project description:Genomic DNA copy number alterations are key genetic events in the development and progression of human cancers. Here we report a genome-wide microarray comparative genomic hybridization (array CGH) analysis of DNA copy number variation in a series of primary human breast tumors. We have profiled DNA copy number alteration across 6,691 mapped human genes, in 44 predominantly advanced, primary breast tumors and 10 breast cancer cell lines. While the overall patterns of DNA amplification and deletion corroborate previous cytogenetic studies, the high-resolution (gene-by-gene) mapping of amplicon boundaries and the quantitative analysis of amplicon shape provide significant improvement in the localization of candidate oncogenes. Parallel microarray measurements of mRNA levels reveal the remarkable degree to which variation in gene copy number contributes to variation in gene expression in tumor cells. Specifically, we find that 62% of highly amplified genes show moderately or highly elevated expression, that DNA copy number influences gene expression across a wide range of DNA copy number alterations (deletion, low-, mid- and high-level amplification), that on average, a 2-fold change in DNA copy number is associated with a corresponding 1.5-fold change in mRNA levels, and that overall, at least 12% of all the variation in gene expression among the breast tumors is directly attributable to underlying variation in gene copy number. These findings provide evidence that widespread DNA copy number alteration can lead directly to global deregulation of gene expression, which may contribute to the development or progression of cancer. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Using regression correlation
2005-09-10 | E-GEOD-3281 | biostudies-arrayexpress
Project description:Centrosome amplification has long been recognized as a feature of human tumors, however its role in tumorigenesis remains unclear. Centrosome amplification is poorly tolerated by non-transformed cells, and, in the absence of selection, extra centrosomes are spontaneously lost. Thus, the high frequency of centrosome amplification, particularly in more aggressive tumors, raises the possibility that extra centrosomes could, in some contexts, confer advantageous characteristics that promote tumor progression. Using a three-dimensional model system and other approaches to culture human mammary epithelial cells, we find that centrosome amplification triggers cell invasion. This invasive behavior is similar to that induced by overexpression of the breast cancer oncogene ErbB2 and indeed enhances invasiveness triggered by ErbB2. We show that, through increased centrosomal microtubule nucleation, centrosome amplification increases Rac1 activity, which disrupts normal cell-cell adhesion and promotes invasion. These findings demonstrate that centrosome amplification, a structural alteration of the cytoskeleton, can promote features of malignant transformation. genome-wide human SNP 6.0 arrays from Affymetrix was used to determine the copy number changes of MCF10A cells with extra centrosomes or depleted of MCAK after grown 4 days in 3-D cultures
2014-03-01 | E-GEOD-55042 | biostudies-arrayexpress
Project description:Generating sufficient DNA for high-throughput genetic analysis has always been a challenge for clinical settings where the amount of source DNA is limited. Multiple displacement amplification (MDA) has been proposed as a promising candidate for such situations. Previous work with lower-resolution arrays confirmed the utility of single-cell MDA products for large-size (~30 Mb) genome variation screening. We tested the performance of single-cell MDA products on the SNP 6.0 arrays to examine the performance of single-cell MDA in SNP genotyping, copy number polymorphism, de novo copy number variation (CNV) and loss of heterozygosity (LOH) analysis. Our data show that for SNP genotyping, single-cell MDA did not obtain complete genome coverage or high sequence fidelity. For CNV calling, single-cell MDA introduced stochastic amplification artifacts in log2 ratio profiles, reducing the robustness of CNV calling; however, by adjusting smooth window size, it is still possible to analyze large chromosomal aberrations, and homozygous deletions as small as 500 kb can still be identified from the noisy log2 ratio profiles. Our results also suggest that even with a modified protocol (reduction of reaction volume, addition of a molecular crowding reagent, minimization of reaction time), single-cell MDA presented little improvement over the unmodified protocol, but by increasing the number of cells as template to 5M-bM-^@M-^S10 cells, SNP 6.0 array results comparable to those of 10 ng genomic DNA MDA could be obtained. Algorithms like PICNIC improved the CNV calling, suggesting that better algorithms can better utilize single-cell MDA array results. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cell line samples, and multiple displacement samples. Genotyping, Copy number and LOH analysis of Affymetrix SNP 6.0 arrays was performed for 3 samples of unamplified cell line genomic DNA, 2 samples of DNA obtained by multiple displacement amplification from 10ng genomic DNA, 3 single-cell multiple displacement amplification (MDA) products, single cell modified MDA amplification product, 5-cell modified MDA amplification product, 10-cell modified MDA amplification product.
2011-03-25 | E-GEOD-28132 | biostudies-arrayexpress