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MicroRNA profiling of seven human breast cell lines and one normal breast RNA sample

ABSTRACT: The small-RNA fraction from seven breast cell lines and one normal breast RNA sample (Ambion) was hybridized against a pool of small-RNA fractions from the six cancer cell lines. We used home-made microRNA-micro arrays (R.Livesey lab, Biochemistry Department, University of Cambridge). For ea ch sample (cell line or normal) we hybridized two technical replicates and two dye-swaps which makes a total of four data sets for each sample.

ORGANISM(S): Homo sapiens

SUBMITTER: Git A

PROVIDER: S-ECPF-UCON-2 | biostudies-other | 2008

REPOSITORIES: biostudies-other

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Project description:BackgroundMicroRNAs (miRs) regulate gene expression through translation inhibition of target mRNAs. One of the most promising approaches for cancer therapy is through mimicking or antagonizing the action of miRs. In this report, we analyzed the miRnome profile of several human breast cancer cell lines to determine the influence of estrogen receptor (ER) silencing previously shown to result in epithelial to mesenchymal transition (EMT) and enhanced tumor invasion.MethodsMicroRNA extracted from MDA-MB-231 (de novo ER-) and ER-silenced (acquired ER-) pII and IM-26 or ER-expressing (YS1.2) siRNA transfected derivatives of MCF7 cells was deep sequenced on Illumina NextSeq500. Respective miRnomes were compared with edgeR package in R and Venny2.1 and target prediction performed with miRTarBase. Mimics and inhibitors of selected differentially expressed miRs associated with EMT mediators (miR-200c-3p targeting ZEB1, miR-449a targeting δ-catenin and miR-29a-3p) were transfected into pII cells and mRNA targets, as well as E-cadherin and keratin 19 (epithelial and mesenchymal markers respectively) were measured using taqman PCR.ResultsEach cell line expressed about 20% of the total known human miRnome; There was a high degree of similarity between the 3 tested ER-lines. Out of these expressed miRs, 50-60% were significantly differentially expressed between ER- and ER + lines. Transfection of miR-200c-3p mimic into pII cells down regulated ZEB1 and vimentin, and increased E-cadherin and keratin 19 with accompanying morphological changes, and reduced cell motility, reflecting a reversal back into an epithelial phenotype. On the other hand, transfecting pII with miR-449a inhibitor reduced cell invasion but did not induce EMT. Transfecting pII cell line with the mimic or inhibitor of miR-29a-3p showed no change in EMT markers or cell invasion suggesting that the EMT induced by loss of ER function can be reversed by blocking some but not just any random EMT-associated genes.ConclusionsThese data suggest that differences in miR expression can be exploited not only as mediators (using mimics) and targets (using miR antagonists) for general cancer therapies aimed at regulating either individual or multiple mRNAs, but also to re-sensitize endocrine resistant breast cancers by turning them back into a type that will be susceptible to endocrine agents.

Project description:Membrane vesicles released by neoplastic cells into extracellular medium contain potential of carrying arrays of oncogenic molecules including proteins and microRNAs (miRNA). Extracellular (exosome-like) vesicles play a major role in cell-to-cell communication. Thus, the characterization of miRNAs of exosome-like vesicles is imperative in clarifying intercellular signaling as well as identifying disease markers. microarray analysis identified several oncogenic miRNA between the two types vesicles. Exosome-like vesicles were isolated using gradient centrifugation from MCF-7 and MDA-MB 231 cultures. Sample-derived miRNA expression was analyzed on Miltenyi's miRXplore™ platform. The RNA was isolated from two replicate samples of MDA-MB231 and MCF7 cell lines. The miRNAs extracted from all four samples were labeled with Hy5 and hybridized against Hy3-labeled Universal Reference miRNA (UR). Candidate miRNAs were identified. In this report, the re-ratios of MDA1 or MDA2 relative to a virtual pool of both MCF7 samples 1 and 2 were used for further analyses. 1- Reratio No. 7 MDA 1 vs MCF7 1+2 reratios of (MDA 1 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970041, (7970039 + 7970040) 2- Reratio No. 8 MDA 2 vs MCF7 1+2 reratios of (MDA 2 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970042, (7970039 + 7970040) Exosome-like vesicles were isolated using gradient centrifugation from MCF-7 and MDA-MB 231 cultures. Sample-derived miRNA expression was analyzed on Miltenyi's miRXplore™ platform. The RNA was isolated from two replicate samples of MDA-MB231 and MCF7 cell lines. The miRNAs extracted from all four samples were labeled with Hy5 and hybridized against Hy3-labeled Universal Reference miRNA (UR). Candidate miRNAs were identified. In this report, the re-ratios of MDA1 or MDA2 relative to a virtual pool of both MCF7 samples 1 and 2 were used for further analyses. 1- Reratio No. 7 MDA 1 vs MCF7 1+2 reratios of (MDA 1 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970041, (7970039 + 7970040) 2- Reratio No. 8 MDA 2 vs MCF7 1+2 reratios of (MDA 2 vs UR) and (MCF7 1 vs UR + MCF7 2 vs UR) 7970042, (7970039 + 7970040)

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MicroRNA profiling of seven human breast cell lines and one normal breast RNA sample

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