Project description:Circulating microRNAs have recently emerged as a new class of promising non-invasive cancer biomarkers. The purpose of this study was the identification by a high-throughput approach (miRNA microarray) of circulating miRNAs associated with breast cancer-derived distant metastasis. To achieve this goal, we resorted to archival plasma samples collected from patients in the control arm of a randomized clinical trial on stage I breast cancer. We compared plasma miRNA levels in patients that developed distant metastasis after a radical or conservative surgery and in those long-term disease-free. Microarray results were technically and independently validated by Real Time PCR. Subsequent in vitro, in vivo and in silico analyses were performed to investigate the miRNA biological/clinical significance in relation with breast cancer progression. We demonstrated that high circulating miR-1246 levels were associated to distant metastasis and that high tissue expression of this miRNA was correlated with unfavorable outcome in ER+HER2- breast cancer patients. In addition, miR-1246 expression was also found to be related with stem-like features.
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes
Project description:Circulating microRNAs have recently emerged as a new class of promising non-invasive cancer biomarkers. The purpose of this study was the identification by a high-throughput approach (miRNA microarray) of circulating miRNAs associated with breast cancer-derived distant metastasis. To achieve this goal, we resorted to archival plasma samples collected from patients in the control arm of a randomized clinical trial on stage I breast cancer. We compared plasma miRNA levels in patients that developed distant metastasis after a radical or conservative surgery and in those long-term disease-free. Microarray results were technically and independently validated by Real Time PCR. Subsequent in vitro, in vivo and in silico analyses were performed to investigate the miRNA biological/clinical significance in relation with breast cancer progression. We demonstrated that high circulating miR-1246 levels were associated to distant metastasis and that high tissue expression of this miRNA was correlated with unfavorable outcome in ER+HER2- breast cancer patients. In addition, miR-1246 expression was also found to be related with stem-like features. 64 samples (32 patients with metastasis and 32 patients with no metastasis) were considered from a total of 208 hybridized samples collected between 1987 and 2004 (including 94 paired samples according to tumor ER status, age at drawing, drawing year, time from surgery, 7 additional samples from 'no evidence of disease' (NED) patients, 10 references, 1 healthy donor and 2 replicated samples)
Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes Sequence library of miRNAs from a single sample of human foetal mesenchymal stem cells. Results tested and confirmed by northern blotting. Please note that only raw data files are available for the embryonic and neual samples and thus, directly submitted to SRA (SRX547311, SRX548700, respectively under SRP042115/PRJNA247767)
Project description:Development of a primary tumor gene expression profile that can predict the presence of circulating tumor cells in the blood of breast cancer patients. The detection of circulating tumor cells (CTCs) in the peripheral blood and microarray gene expression profiling of the primary tumor are two promising new technologies able to provide valuable prognostic data for patients with breast cancer. In the current study, we aimed to develop a novel profile which provided independent prognostic data by building a signature predictive of CTC status rather than outcome. Seventy-two primary breast cancer tumor have been analyzed against a breast cancer reference pool.