Expression profiling of circulating miRNAs in Luminal A breast cancer

ABSTRACT: Breast cancer is a common disease with distinct tumor subtypes which can be phenotypically characterized by estrogen receptor, progesterone receptor and HER2/neu receptor status. MiRNAs play regulatory roles in tumor initiation and progression. Altered miRNA expression has been demonstrated in a variety of cancer states to date presenting the potential for exploitation as cancer specific biomarkers. Blood presents an attractive medium biomarker discovery. This study investigated systemic miRNAs differentially expressed in Luminal A (ER+PR+HER2/neu-) breast cancer and their effectiveness as oncologic biomarkers in the clinical setting. Blood samples were prospectively collected from consenting patients with Luminal A breast cancer (n=10) and controls (n=10). RNA was extracted, reverse transcribed and subjected to microarray analysis (n=10 Luminal A; n=10 Control). Differentially expressed miRNAs were identified by artificial neural network (ANN) data-mining algorithms. Ethical approval was granted by the Clinical Research Ethics Committee, Galway Roscommon University Hospital Group. Written informed consent was obtained from all study participants. Blood samples were prospectively collected from 20 women; this included 10 consecutive women with a new diagnosis of Luminal A breast cancer and 10 healthy control participants. Luminal A status was confirmed with immunohistochemistry and fluorescence in situ hybridization (FISH). The blood samples for the healthy control group were collected from women residing in the same catchment area as the cancer cases. These women had no personal history of malignancy and no current inflammatory or infectious condition. Venous non-fasting whole blood samples were collected in BD vacutainers M-BM-. containing 18mg dipotassium EDTA anticoagulant (BD-Plymouth, PL6 7BP, UK). Total RNA was extracted from blood (1ml) using TRI Reagent BD (Molecular Research Centre, Inc). RNA concentration and integrity were evaluated by NanoDrop spectrophotometry (NanoDrop ND-1000 Technologies Inc., DE, USA) and Agilent Bioanalyzer RNA 6000 NanoChip Kit Series II (Agilent Technologies, Germany) analysis, respectively. MiRNA microarray profiling Expression profiling of circulating miRNAs was performed using TaqMan miRNA arrays and assays in accordance with the manufacturerM-bM-^@M-^Ys instructions (Taqman Low Density Array Human microRNA Card A and Card B, Applied Biosystems, Foster City, CA, USA). In short, total RNA was reverse transcribed using Megaplex primer pool A (Applied Biosystems) which contained sequence-specific primers for 381 specific miRNAs plus 3 controls (pool A). An additional panel of 384 miRNAs (381 miRNAs and 3 controls, pool B) was performed on a subset of 4 cancers and 4 controls. Real-time quantitative PCR was performed for 667 miRNAs, using A and B microfluidic cards, each containing primers and probes for 381 specific miRNAs plus 3 controls and thermal-cycled on an Applied Biosystems 7900HT instrument. The TLDA cards contain three endogenous controls (RNU44, RNU48 and MammU6 which is repeated four times on each card). Each card also contains a negative control, an assay unrelated to any human species, ath-miR-159a.

ORGANISM(S): Homo sapiens

SUBMITTER: Graham Ball 

PROVIDER: E-GEOD-46355 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress