MicroRNAs and adhesion molecules involved in tumor progression
The main research goal in the lab is the identification and characterization of microRNAs (miRNAs) involved in tumor progression, for breast cancer and melanoma. We use human tumor samples and cellular models to evaluate deregulated miRNAs in malignant versus non-malignant conditions and then we study the function and the molecular mechanisms of the most deregulated small non-coding RNAs in cell lines. Finally, we aim at using the most deregulated miRNAs as putative targets for therapy. Therefore, we prepare and evaluate tools that can be administered in vivo for pre-clinical studies such as stabilized anti/pre-miRNAs and aptamers conjugated with anti/pre-miRNAs. We recently identifed a group of deregulated miRNAs that can be used to classify breast tumors and predict the outcome of the desease. In addition, we identified miR-214, overexpressed in malignant melanomas, and proved its pro-metastatic function. On other hand, we found low expression of miR-148b in relapsed breast tumors and in malignant melanomas and revealed its anti-metastatic role. Generally, in our laboratory, relevant miRNAs are overexpressed or silenced in cell lines and their biological function is evaluated in terms of proliferation, apoptosis, tumor formation and in particular migration/invasion and metastasis dissemination by performing in vitro (cell culture) and in vivo (mouse) experiments. Since miRNAs regulate protein-coding gene expression it is essential to identify the miRNA target genes responsible of certain biological funcitons. For this purpose we use protein-coding gene expression profiles and computational predictions with several algorithms. The targets are validated using luciferase reporter vectors containing 3’UTR sequences of the potential target genes and by western blot analyses. We are particularly interested in targets with adhesion functions since tumor progressioni s driven by adhesion/cell-cell contacts molecules. Examples of our preferred targets are integrins, cadherins, ESDN, ALCAM. We also generate trangenic and knock out mouse models for one or more identified miRNAs to study the function in vivo and to evaluate the potential of our candidate miRNAs as targets for gene therapy in tumors.