Epigenetic regulation of Ewing's sarcoma stem cells

Emerging evidence suggests that cancer stem-like (CS-like) cells are responsible for cancer progression and relapse. The identification and characterisation of CS-like cells is therefore important to reveal potential targets that could be used to design more effective personalised treatment to improve outcomes. The cell surface marker prominin-1 (CD133) has been used to identify Ewing sarcoma (ES) CS-like cells (ES-CS-like), however some primary ES cells are devoid of CD133 and may be down-regulated by the microenvironment in cell culture. Therefore, alternative approaches are required to identify ES-CS-like cells. Two approaches were compared to enrich for putative ES-CSCs from ES cell lines; isolation of ES-CS-like cells by CD133 expression and using a functional single cell self-renewal assay. The second approach was more reliable for studying the miRNA and mRNA expression profiles in ES-CS-like spheroids compared to ES cells grown as monolayers. In ES-CS-like spheroids, the expression of the stem cell marker EBAF (q<0.03), miR-210-3p (q<0.12) and the ABC transporter protein ABCG1 (q