Expression of miR-125b in the new, highly invasive glioma stem cell and progenitor cell line SU3

MicroRNA (miR)-125b has been shown to play a potential role in the development of glioma stem cells. However, the relationship between miRNA and glioma stem cells is still elusive. This study was designed to elucidate this potential relationship. We established a highly invasive glioma stem cell and progenitor (GSCP) cell line SU3. SU3 cell suspensions were injected into nude mice brains in situ, and the invasiveness of graft tumors was analyzed using hematoxylin and eosin staining as well as immunohistochemistry. Real-time polymerase chain reaction (PCR) was used to measure the expression levels of miR-125b in SU3 and other cells. In vitro, SU3 cells expressed CD133 and nestin as well as differentiation markers glial fibrillary acidic protein (GFAP) and β-tubulin III, which were consistent with the characteristics of glioma stem cells. Scratch assays indicated that the migration ability of SU3 cells was stronger than that of U251 stem cells (U251s). In vivo, SU3 cells invaded into each part of the mouse brain from the caudate nucleus in a diffuse pattern and highly expressed invasive and proliferative cell markers matrix metalloprotease 2 (MMP2), MMP9, and Ki-67. Real-time PCR results revealed that the levels of miR-125b and MMP9 were significantly higher in SU3 and SU2, also a highly invasive GSCP cell line we established before, than in U251s. High expression of miR-125b both in newly established GSCPs, SU3, and long-term cultured GSCPs, SU2 suggests that miR-125b exhibits oncogene-like behavior. This behavior should be considered in further studies of miR-125b in cancer stem cells. Furthermore, MMP9, which plays a role in cancer stem cell invasion, may be a target gene of miR-125b.