SH3BGRL3, transcribed by STAT3, facilitates glioblastoma tumorigenesis by activating STAT3 signaling

Glioblastoma (GBM) is the most aggressive tumors of the central nervous system. Here, we report that SH3 binding glutamic acid-rich protein like 3 (SH3BGRL3) was extremely highly expressed in GBM and glioma stem cells. SH3BGRL3 high expression associates with worse survival of GBM patients. Functionally, Targeting SH3BGRL3 obviously impairs GSCs self-renewal in vitro. Most importantly, we first report that SH3BGRL3 is a direct transcriptional target gene of signal transducer and activator of transcription 3 (STAT3) and thereby activating STAT3 signaling in turn. Additionally, forced expression of the constitutively activated STAT3 (STAT3-C) rescued GSCs self-renewal inhibited by SH3BGRL3 silencing. Collectively, we first identified a critical positive feedback loop between SH3BGRL3 and STAT3, which facilitates the tumorigenic potential of GBM.