Project description:Total RNA from 46 breast cell lines was labelled using the Illumina TotalPrep RNA Amplification kit (Ambion) following manufacturer's instructions. 1.5 µg of biotin-labelled cRNA were used for each hybridisation on Sentrix Human-6 v1 BeadChips (Illumina, San Diego, CA) following manufacturer's protocol.
Project description:Transcriptional profiling was conducted on RNA from 23 breast cancer cell lines to identify genes whose expression level correlates with sensitivity of particular drug Experiment Overall Design: Baseline gene expression profiling was performed using 23 breast cancer cell lines to identify genomic signatures highly correlated with in vitro sensitivity to a particular drug
Project description:Cyclic indole-3-carbinol (I3C) tetrameric derivative (CTet) is an anticancer molecule that has been shown to exert an antiproliferative activity in both MCF-7 and MDA-MB-231 breast cancer cell lines. To characterize the molecular mechanisms leading to the inhibition of the cell proliferation, gene expression analyses were conducted. MCF-7 and MDA-MB-231 breast cancer cells were plated in 6-wells culture plates at density of 150,000 cells/well and cultured overnight. Cellular treatments were conducted at 6uM and 12 uM concentration of CTet, or vehicle control, for 24 h. Cell survival was evaluated by trypan blue dye exclusion assay and, after washing in phosphate buffered saline (PBS), the cells were pelletted by centrifugation and stored at -20°C with 300µl of RNA-later solution (Sigma-aldrich). Total RNA was purified from treated and control cells using the RNeasy plus kit (Qiagen). Biotin-labeled cRNA was synthesized using the CodeLink iExpress Assay reagent kit (GE Healthcare), following the manufacturer’s protocols. Biotin-labeled cRNA obtained from each biological sample was fragmented and hybridized against three independent arrays (10 ug each) at 37°C for 22 h. After hybridization, the arrays were washed, stained with Cy5-streptavidin and scanned using a ScanArray GX scanner (Perkin Elmer), with a resolution of 5 um. The image files generated by the scanner were processed using the Codelink Expression Analysis software (GE Healthcare). Normalized data from the Codelink software package were analyzed with GeneSifter software (www.genesifter.net; Geospiza Inc., Seattle, WA) for statistical validation and data mining. Normalized data of the two experiments were subjected to analysis of variance (ANOVA) and 5% false discovery rate calculation (Benjamini and Hochberg). The cut-off parameters for differential gene expression were p =0.01 and fold change threshold =2.
Project description:Breast cancer subtypes identified in genomic studies have different underlying genetic defects. Mutations in the tumor suppressor p53 occur more frequently in estrogen receptor (ER) negative, basal-like and HER2-amplified tumors than in luminal, ER positive tumors. Thus, because p53 mutation status is tightly linked to other characteristics of prognostic importance, it is difficult to identify p53's independent prognostic effects. The relation between p53 status and subtype can be better studied by combining data from primary tumors with data from isogenic cell line pairs (with and without p53 function). In this study, the p53-dependent gene expression signatures of four cell lines (MCF-7, ZR-75-1, and two immortalized human mammary epithelial cell lines) were identified by comparing p53-RNAi transduced cell lines to their parent cell lines. Cell lines were treated with vehicle only or doxorubicin to identify p53 responses in both non-induced and induced states. Each cell line displayed unique patterns of gene expression, but cell type specific trends were evident. A common gene expression signature associated with p53 loss across all four cell lines was identified. This signature showed overlap with the signature of p53 loss in primary breast tumors and predicted relapse-free survival and overall survival in independent test data sets. Experiment Overall Design: We analyzed 48 arrays performed using 48 polyA RNA samples. RNAs were collected from cell lines treated with an IC50 dose of doxorubicin hydrochloride or with a feeding control. Each cell line had its own reference which represented the second sample on the dual channel array. These untreated RNAs were prepared by pooling four harvests of that cell line at 60-80% confluence and 48h after feeding
Project description:We describe a novel approach combining RNAi screening in multiple cell lines with expression profiling to identify novel cancer targets in breast cancer cell lines