BMP4 induces asymmetric cell division in human glioma stem-like cells

Glioblastoma (GBM) is a malignant tumor with a high recurrence rate and has very poor prognosis in humans. The median survival is still <2 years. Therefore, a new treatment strategy should be established. Recently, this cancer has been thought to be heterogeneous, consisting of cancer stem cells (CSCs) that are self-renewable, multipotent, and treatment resistant. So various strategies targeting glioma stem-like cells (GSCs) have been investigated. This study focused on strategies targeting GSCs through the induction of differentiation using bone morphogenetic protein 4 (BMP4). The expression of CD133, a cancer stem cell marker, under BMP4 treatment in GSCs was examined using flow cytometry, western blotting, and quantitative PCR. Immunofluorescent staining of GSCs was also performed to examine the type of cell division: asymmetric cell division (ACD) or symmetric cell division (SCD). We obtained the following results. The BMP4 treatment caused downregulation of CD133 expression. Moreover, it induced ACD in GSCs. While the ACD ratio was 23% without BMP4 treatment, it was 38% with BMP4 treatment (P=0.004). Furthermore, the tumor sphere assay demonstrated that BMP4 suppresses self-renewal ability. In conclusion, these findings may provide a new perspective on how BMP4 treatment reduces the tumorigenicity of GSCs.