Studio molecolare e funzionale della famiglia del miR-302 in cellule staminali e tumorali

MicroRNAs, also called miRNA or miR are short ribonucleic acid molecules of 19-24 nucleotides that play an important regulatory role in the expression of cellular proteins through post-transcriptional gene silencing. Despite their identification and description is relatively recent, the microRNAs are assigned tasks that involve almost all physiological and pathological cellular processes. Our research has focused on the study of a family of microRNAs, miR-302. Among more than 700 miRNA identified, the miR-302 seems to be more expressed in embryonic stem cells (-ES-) and is one of microRNAs with the highest specificity of expression. We performed a molecular study of miR-302 on expression profiles from human embryonic stem cells (hESCs) and hESC in differentiation in order to describe the correlation between the different expression profiles and the cell state. The hypothesis of CSC (Cancer Stem Cells) provides an explanation for the refractoriness to treatment and the latent ability of certain cancers. Our laboratory have been discovered a number of miRNAs that play a critical role in cancer and therefore our research focus on investigating the expression levels in normal tissues and tumor counterparts. We then examined the expression of mir-302 in samples of ductal carcinoma in situ and invasive carcinoma of the breast samples. In situ hybridization investigation has found that the MIR-302 is present in the infiltrating ductal carcinoma, but not in cells of normal tissue. In addition, primary tumors with lymph node metastasis have an excess of tumor cells expressing the mir-302. Based on this observation, we sought to understand the mechanisms that lead to the expression of the cluster. We observed that tumor cell lines of breast cancer treated in conditions of hypoxia express the miR-302b, while the counterpart in normoxia do not express it. According to the screening carried out on the tissues of patients the miR-302 bound to metastases and especially to the lower survival of the individual, the target validation of estrogen receptor ER-alpha in epithelial cell lines has led us to have several assumptions about the role that could have the expression of miR-302 on epithelial mesenchymal transition EMT and its counterpart, MET and the further role in metastasis. The choice of generating a mouse Knock in that express miR-302 marked by a reporter gene, ZsGreen, will lead to a series of in vivo studies for the coming years.