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Gene expression in endometrial cancer cells (Ishikawa) after short time high dose exposure to progestins

ABSTRACT: Gene expression in endometrial cancer cells (Ishikawa) after short time exposure to progestins Sample and RNA preparation: The series is composed of sixteen hybridizations for analysis of differentially expressed genes in endometrial cancer cells (Ishikawa). In eight independent experiments, Ishikawa cells in monolayer received with 30 ug/ml progestin and were grown in RPMI-1640 medium (Sigma, Sty. Louis) with 10% dialyzed foetal calf serum (PAA-laboratories, Austria) without phenol red and antibiotics. Cells were seeded at a density of 1 x 105 cells/ml in 25 cm2 culture flasks in a humidified atmosphere (5% CO2) at 37°C for 4 hours. Cells not treated with progestin served as control groups. Total RNA extraction was performed using TRIZOL Reagent (GIBCO BRL Life Technologies, New York, NY). Labeling and hybridization: Total RNA was reverse transcribed and labeled with Cy3- and Cy5- attached dendrimer, respectively, using the Genisphere 3DNA 350HS kit (Genisphere, Montvale, NJ) as described in the manufacturer's protocol. Hybridizations of transcribed probes were carried out in a TECAN HS4800 instrument using the formamide-based hybridization buffer from Genisphere containing 5% dextrane sulfate and 5.5 ng/ul COT1 DNA (GIBCO BRL Life technologies) at 37º for 23 hours. 3DNA dendrimer hybridizations were carried out in formamide-based hybridization buffer alone. Post-hybridization washes were carried out at room temperature with 2xSSC for 1 min, 0.2% SDS /2xSSC for 1 min and finally with 0.2xSSC for 30 sec. Sixteen hybridizations including dye-swap have been performed for eight independent experiments. Scanning, image analysis and data processing: The arrays were scanned with the GenePix 4000B scanner (Axon Instruments Inc). The features were extracted from the arrays using GenePix Pro 6.0 (Axon instruments Inc., Union City, CA). All subsequent statistical analyses were performed using the statistical package R (R Development Core Team). Spots that displayed a signal-to-noise ratio of less than 2, or that were significantly saturated (more than 20 % saturation among foreground pixels) were filtered out. The median was used as the averaging measure of the foreground pixels. After quality control, genes that were present in less than 50 % of the arrays were filtered out. The arrays were normalized using dye-swap normalization. One array, whose dye swap twin failed was normalized using the lowess method. Statistical significance was assigned to the genes using the SAM methodology. The bioconductor SAMR package was used in the actual analysis. Missing expression levels were imputed using 10 nearest neighbour's imputation. The local FDR threshold was set to 25 %. Keywords: Progestin treatment, Control-treatment

ORGANISM(S): Homo sapiens

PROVIDER: GSE7184 | GEO | 2007/04/13

SECONDARY ACCESSION(S): PRJNA98337

REPOSITORIES: GEO

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Gene expression in endometrial cancer cells (Ishikawa) after short time high dose exposure to progestins

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