Project description:MicroRNAs (miRNAs) play an important role in the regulation of gene expression and are often dysregulated in disease. The recent development of the CRISPR-Cas9 gene-editing system, composed of the Cas9 nuclease in complex with a single guide RNA (sgRNA), allows researchers to direct DNA cleavage at a predetermined site and to conduct genome-scale knockout screens. To determine the functional role of miRNAs in cancer, we designed and constructed a library of 7,382 sgRNAs to target 85% of the 1,881 annotated human miRNA stem-loops. We then examined the role of miRNAs in HeLa cell fitness by monitoring the change in frequency of each sgRNA over time. We identified 44 pro-proliferative miRNAs from two replicate experiments, including miR-31, a known cervical cancer overexpressing miRNA that enhances HeLa cell proliferation. We also examined the role of miRNAs in NCI-N87 gastric cancer cells and identified 10 pro-fitness and 10 anti-fitness miRNAs. In both screens, many of the pro-fitness miRNAs identified are overexpressed in tumors cervical tumors for HeLa or gastric tumors for NCI-N87. In summary, we present a CRISPR miRNA-targeted screen which was able to identify both known and novel fitness-associated miRNAs in the HeLa and NCI-N87 cell lines.
Project description:The aim of our study was to assess miRNA expression of canine mammary cancer stem cells. Three canine mammary cancer cell lines (CMT-U27, CMT-U309 and P114) were stained using Anti-Sca1 (Stem cell antigen 1) antibodies. The FACS analysis showed 0,3-1% of Sca1+ cells in each of the cell line. The cells were sorted (using FACS Aria II) as Sca1+ and Sca1- and subjected to further analysis of miRNA expression (using Agilent custom miRNA microarray).