Upstream stimulating factor1 (USF1) enhances the proliferation of glioblastoma stem cells mainly by activating the transcription of mucin13 (MUC13)

Glioblastoma is one of the most aggressive and deadly tumors among the adults. MUC13 is a membrane bound mucin and abnormal expression of MUC13 has been identified in various tumors. However, its specific role in glioblastoma has never been explored. Firstly, the expression of MUC13 was explored in glioblastoma stem cells (GSCs) and we found that MUC13 was significantly enhanced in GSCs. Overexpression of MUC13 significantly enhanced GSCs invasion and migration capacities. Further study showed that overexpression of MUC13 significantly increased the phosphorylation levels of AKT and P38. Dual luciferase reporter and ChIP assay demonstrated that USF1 could bind the promoter region of MUC13, thereby enhancing the activation of MUC13. More importantly, when MUC13 was silenced, the phosphorylation levels of AKT and P38 were suppressed even in cells transfected with ad-USF1. These data showed that USF1 prompted glioblastoma progression mainly by activating MUC13. In summary, our study first demonstrated that USF1 could activate the transcription of MUC13, thereby enhancing the proliferation and self-renewal of GSCs.