Unknown,Transcriptomics,Genomics,Proteomics

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Molecular profiling of breast cancer cell lines defines relevant tumor models (aCGH)

ABSTRACT: Breast cancer cell lines have been used widely to investigate breast cancer pathobiology and new therapies. Breast cancer is a molecularly heterogeneous disease, and it is important to understand how well and which cell lines best model that diversity. In particular, microarray studies have identified molecular subtypes - luminal A, luminal B, ERBB2-associated, basal-like and normal-like - with characteristic gene-expression patterns and underlying DNA copy number alterations (CNAs). Here, we studied a collection of breast cancer cell lines to catalog molecular profiles and to assess their relation to breast cancer subtypes. Whole-genome DNA microarrays were used to profile gene expression and CNAs in a collection of 52 widely-used breast cancer cell lines, and comparisons were made to existing profiles of primary breast tumors. Hierarchical clustering was used to identify gene-expression subtypes, and Gene Set Enrichment Analysis (GSEA) to discover biological features of those subtypes. Genomic and transcriptional profiles were integrated to discover within high-amplitude CNAs candidate cancer genes with coordinately altered gene copy number and expression. Transcriptional profiling of breast cancer cell lines identified one luminal and two basal-like (A and B) subtypes. Luminal lines displayed an estrogen receptor (ER) signature and resembled luminal-A/B tumors, basal-A lines were associated with ETS-pathway and BRCA1 signatures and resembled basal-like tumors, and basal-B lines displayed mesenchymal and stem-cell characteristics. Compared to tumors, cell lines exhibited similar patterns of CNA, but an overall higher complexity of CNA (genetically simple luminal-A tumors were not represented), and only partial conservation of subtype-specific CNAs. We identified 80 high-level DNA amplifications and 13 presumptive homozygous deletions, and the resident genes with concomitantly altered gene-expression, highlighting known and novel candidate breast cancer genes. Overall, breast cancer cell lines were genetically more complex than tumors, but retained expression patterns with relevance to the luminal-basal subtype distinction. The compendium of molecular profiles defines cell lines suitable for investigations of subtype-specific pathobiology, biomarkers and therapies, and provides a resource for discovery of new breast cancer genes. cDNA microarrays from the Stanford Functional Genomics Facility were used to carry out array-based Comparative Genomic Hybridization (array CGH) analysis of 52 human breast epithelial cell lines, in comparison to normal female DNA. Three reference arrays of normal male vs. normal female DNA were also done. Map positions for arrayed cDNA clones were assigned using the NCBI genome assembly, accessed through the UCSC genome browser database (NCBI Build 36). The cghFLasso method was used to call DNA gains and losses.

ORGANISM(S): Homo sapiens

SUBMITTER: Jonathan Pollack

PROVIDER: E-GEOD-13914 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Molecular profiling of breast cancer cell lines defines relevant tumor models and provides a resource for cancer gene discovery.

Kao Jessica J Salari Keyan K Bocanegra Melanie M Choi Yoon-La YL Girard Luc L Gandhi Jeet J Kwei Kevin A KA Hernandez-Boussard Tina T Wang Pei P Gazdar Adi F AF Minna John D JD Pollack Jonathan R JR

PloS one 20090703 7

<h4>Background</h4>Breast cancer cell lines have been used widely to investigate breast cancer pathobiology and new therapies. Breast cancer is a molecularly heterogeneous disease, and it is important to understand how well and which cell lines best model that diversity. In particular, microarray studies have identified molecular subtypes-luminal A, luminal B, ERBB2-associated, basal-like and normal-like-with characteristic gene-expression patterns and underlying DNA copy number alterations (CNA ...[more]

PMID: 19582160

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Project description:These 95 arrays are the basis for Figure 2 of our manuscript "An interferon-response induced by tumor-stroma interaction in a subset of human breast cancers". Abstract:Background Communication between different cell types is a cardinal feature of multi-cellular organisms and perturbations in these cell-cell interactions are a key feature of cancer. However, little is known about the systematic effects of cell-cell interaction on global gene expression in cancer. Methods and Findings We used an ex vivo culture model to simulate tumor-stroma interaction by systematically co-cultivating breast cancer cells with stromal fibroblasts and determined associated gene expression changes with cDNA microarrays. The picture of heterotypic interaction effects that emerged from this analysis is complex, reflecting the variation in signaling capacities and responsiveness of the involved cells. A frequent and prominent response to epithelial-mesenchymal interaction was an induction of interferon-response genes, observed in 4 of the 7 breast cancer cell lines in response to co-culture with fibroblasts, but not in normal mammary epithelial cells. In response to close contact with these breast cancer cells, the fibroblasts secreted type I interferons, which, in turn, induced expression of the IRGs in the tumor cells. Immunohistochemical analysis of human breast cancer tissues showed that STAT1, the key transcriptional activator of the interferon-response genes, and itself an IRG, was expressed in a subset of the cancers, with a striking pattern of elevated expression in the cancer cells in contact with, or close proximity to, the tumor stroma ? paralleling the response seen in our ex vivo model. In vivo, expression of the interferon-response genes was remarkably coherent, providing a basis for segregation of the 295 early-stage breast cancers into two groups. Tumors with high expression levels (n=161) of IRG were associated with significantly shorter overall survival; 59 % at 10 years versus 80% for tumors with low interferon-response gene expression levels (n=134) (log-rank p=0.001). Conclusion Our results suggest that an interaction between some breast cancer cells and stromal fibroblasts can induce an interferon response, and that this response may be associated with a greater propensity for tumor progression. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed

Project description:Patient Selection: Three hospitals were involved in the study: Dong Thap Provincial and An Giang Provincial hospitals, both located in the Mekong Delta Region of Vietnam where most of the Typhoid patients were admitted, and the Hospital for Tropical Diseases, Ho Chi Minh City, where the malarial patients were admitted. Infection status of each patient was determined by blood culture for the Typhoid patients and by microscopic examination of stained thick and thin peripheral-blood slides for the patients suspected of having Malaria. Patients with blood cultures positive for S. Typhi or S. enterica serovar Paratyphi A (S. Paratyphi A) (samples designated ST) or peripheral blood smears positive for Plasmodium falciparum or Plasmodium vivax (samples designated PF) were consented and enrolled in the study. A total of 28 S. Typhi positive patients and one S. Paratyphi A positive patient were enrolled in the first phase of the study and a further 9 S. Typhi and one S. Paratyphi A positive patient were enrolled in the second phase. Nine patients with Malaria caused by P. falciparum and one caused by P. vivax were enrolled. Sixteen uninfected healthy individuals (samples designated HC) were also enrolled in the study (one sample each). The Typhoid patients were randomly chosen to receive either Azithromycin or Gatifloxicin (20mg/kg/day for 7 days) antibiotics. Uncomplicated malaria patients were treated for 3 days with Artekin (dihydroartemisinin with piperaquine phosphate). Venous blood (2.5ml) was collected for total RNA extraction into PaxGene RNA collection tubes (Qiagen) at various times. The first sample (T1) was taken immediately on admission or entry into the study, then samples were collected, 3 (T3), 6-9 (T9 for Typhoid, T7 for Malaria), and 28-45 (T28) days following entry into the study and an average of 9 months (T9M) later. The PaxGene tubes were stored at 4degC until RNA was extracted as per the manufacturers instructions. Purified RNA was shipped on dry ice to Stanford University, CA for use in Microarray analyses. Microarrays: Experimental and reference samples (Human Universal RNA reference {Stratagene}) were amplified using the MessageAmp II aRNA Kit (Ambion) as per the manufacturer's instructions. Four micrograms amplified RNA was labeled through indirect incorporation of Cy5 (experimental) and Cy3 (reference) dyes (protocols can be found at http://cmgm.stanford.edu/pbrown/protocols/index.html). The labeled probes were then mixed and hybridized to Stanford Human cDNA arrays with 42 K features. Arrays were scanned using a Genepix 4000A laser scanner and data extracted with Genepix Pro Software version 5.1 (Axon Instruments). The data were then uploaded into the Stanford Microarray Database (SMD). A disease state experiment design type is where the state of some disease such as infection, pathology, syndrome, etc is studied. Compound Based Treatment: Drugs used for treatment Disease State: Malaria, Typhoid or Healthy Controls Keywords: disease_state_design Complex

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Molecular profiling of breast cancer cell lines defines relevant tumor models (aCGH)

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Molecular profiling of breast cancer cell lines defines relevant tumor models and provides a resource for cancer gene discovery.

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