However, each also plays additional distinct roles in the immune system

n-coding single-stranded RNAs that regulate gene expression. Specific binding of miRs to the 39 untranslated region of target gene mRNA results in suppressed target gene translation which may also be associated with degradation of the target gene mRNA. Although miRs play key roles during normal developmental processes, deregulation of miR expression has been noted in LY3039478 several human cancers where miRs have been shown to have both oncogenic and tumor suppressor functions. MiR-7 has been shown to suppress breast tumorigenesis by reducing expression of multiple target genes including epidermal growth factor receptor , p21-activated kinase 1 , focal adhesion kinase , and krupple-like factor 4 . Here we show that breast tumor cells expressing oncogenic HER2D16 have 2 / 16 MiR-7 Suppresses HER2D16 Oncogenic Activity reduced expression of the miR-7 tumor suppressor. Accordingly, reintroduced miR-7 expression suppressed HER2D16 oncogenic activity by inhibiting expression of EGFR and independently inactivating Src kinase. Materials and Methods Cell lines MCF-7 cells were purchased from American Type Culture Collection and cultured according to their instructions. The stable MCF-7 cell line expressing pcDNA3 or the two independent cell lines expressing pcDNA3-HER2D16 and referred to here as MCF-7/pcDNA, MCF-7/HER2D16H, and MCF-7/HER2D16M1, respectively, have been PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19681699 described elsewhere. For stable suppression of EGFR to generate the pooled MCF-7/HER2D16/EGFRKD cell line, MCF-7/HER2D16H cells were transfected with the MISSION shRNA plasmid-DNA TRCN0000121329 targeting EGFR or a pLKO.1 negative control using Fugene6. For stable suppression of miR-7 to generate the pooled MCF-7/miR-7KD cell line, MCF-7 cells were transfected with the miRZip-7 anti-miR-7 microRNA construct MZIP7-PA-1 or the pGreenPuro Scramble Hairpin Control construct MZIP000-PA-1 using Fugene6. For stable expression of miR-7 to generate the pooled MCF-7/HER2D16H/miR-7 cell line, MCF-7/HER2D16H cells were transfected with the miR-7 expression vector MI0000263 using the NEON Transfection System exactly as described by the manufacturer. At two days post-transfection all pooled cell lines were selected for two days in 1 mg/ml puromycin and then maintained at 0.2 mg/ml puromycin. Micro RNA expression profiling Four independent total RNA samples from MCF-7/pcDNA and MCF-7/ HER2D16H cells were purified using the miRVANA RNA Isolation System according to the manufacturer’s instructions and RNA integrity was confirmed using a Bioanalyzer. Microarray assay was performed and analyzed using a service provider and LC-Science PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19681941 microRNA array miRHuman_11.0 which detects miR transcripts listed in Sanger miRBase Release 11.0. The microRNA array data presented in this publication have been deposited in NCBI’s Gene Expression Omnibus and are accessible through GEO Series accession number GSE62848. Quantification of miR-7 expression Triplicate total RNA samples were purified using the miRVANA RNA Isolation System according to the manufacturer’s instructions and RNA integrity was confirmed using a Bioanalyzer. First-strand complementary DNA was synthesized from 1.0 mg of total RNA in a 20 ml reaction 3 / 16 MiR-7 Suppresses HER2D16 Oncogenic Activity volume using the Superscript III First-Strand Synthesis System with a RNU44 or dme-miR-7 RT-primer exactly as described by the manufacturer. Following reverse transcription, 180 ml of water was added to the cDNA reaction and 2 ml of the diluted cDNA was used in