Enrichment of A Rare Subpopulation of miR-302-Expressing Glioma Cells by Serum Deprivation

Objective: mir-302-367 is a cluster of polycistronic micrornas that are exclusively expressedin embryonic stem (es) cells. the mir-302-367 promoter is functional duringembryonic development but is turned off in later stages. motivated by the cancer stemcell hypothesis, we explored the potential expression of mir-302 in brain tumor cell lines.materials and methods: in the present experimental study, we have tried to expandour knowledge on the expression pattern and functionality of mir302 cluster by quantifyingits expression in a series of glioma (a-172, 1321n1, u87mg) and medulloblastoma(daoy) cell lines. to further assess the functionality of mir-302 in these celllines, we cloned its promoter core region upstream of the enhanced green fluorescentprotein (egfp) or luciferase encoding genes.results: our data demonstrated a very low expression of mir-302 in glioma cell lines,compared with that of embryonal carcinoma cell line nt2 being used as a positivecontrol. the expression of mir-302 promoter-egfp construct in the aforementionedcell lines demonstrated gfp expression in a rare subpopulation of the cells. serumdeprivation led to the generation of tumorospheres, enrichment of mir-302 positivecells and upregulation of a number of pluripotency genes.conclusion: taken together, our data suggest that mir-302 could potentially be used asa novel putative cancer stem cell marker to identify and target cancer stem cells withintumor tissues.