Abstract P4-09-09: Verification of the breast cancer progression-associated miRNA hsa-miR-199a-5p using NanoString® platform

A fundamental and clinically important step during breast tumourigenesis is the transition from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC). Improved knowledge of this transition from pre-invasive to invasive breast cancer will pave the way for novel preventative and therapeutic strategies. We have previously reported on differential expression of the miRNA hsa-miR-199a-5p in 15 matched pairs of DCIS and IDC areas isolated by laser capture microdissection (LCM) from formalin fixed and paraffin embedded (FFPE) breast cancer tissues using Illumina miRNA BeadChip microarray platform. Differential expression of hsa-miR-199a-5p was validated by quantitative RT-PCR in additional independent DCIS/IDC sample pairs from 25 breast cancer patients. Knock down of hsa-miR-199a-5p in invasive MDA-MB-231 and TMX2-28 breast cancer cells using a specific inhibitor significantly reduced invasiveness by approx. 73% and 71%, respectively (P Now we report on experiments to validate differential expression of hsa-miR-199a-5p using a new platform – NanoString® (nCounter® miRNA Expression Assay, NanoString Technologies®). The NanoString® System is an automated, digital detection and counting system which uses a novel barcoding technology to directly profile up to 800 miRNAs simultaneously from a single sample. Total RNA from 6 DCIS/IDC FFPE tumours was used for miRNA expression analysis. This analysis resulted in 10 differentially expressed miRNAs including hsa-miR-199a-5p which is upregulated in IDC (P In this project we identified candidate progression-associated miRNAs which are differentially expressed between DCIS and IDC. Hsa-miR-199a-5p was validated in an independent sample cohort and its expression was further verified using the new miRNA expression analysis platform NanoString®. Hsa-miR-199a5-p is influencing in vitro cell invasiveness and may therefore be a potential drugable regulator of tumour progression and invasion in breast cancer. Citation Format: Fehm T, Schultz S, Bartsch H, Petat-Dutter K, Kahlert S, Sotlar K, Niederacher D, Neubauer H. Verification of the breast cancer progression-associated miRNA hsa-miR-199a-5p using NanoString® platform. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-09-09.