RESUMO
Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. The aberrant activation of STAT3 commonly occurs in GBM and is a key player in GBM tumorigenesis. Yet, the aberrant activation of STAT3 signaling is not fully understood. Here, we report that SH2B adaptor protein 3 (SH2B3) is highly expressed in GBM and preferentially expressed in GBM stem cells (GSCs). Moreover, SH2B3 high expression predicts worse survival of GBM patients. Targeting SH2B3 considerably impairs GBM cell proliferation, migration, and GSCs' self-renewal in vitro as well as xenograft tumors growth in vivo. Additionally, we provide evidence suggesting that STAT1 directly binds to the promoter of SH2B3 and activates SH2B3 expression in the transcriptional level. Functionally, SH2B3 facilitates GBM progression via physically interacting with gp130 and acting as an adaptor protein to transduce IL-6/gp130/STAT3 signaling. Together, our work firstly uncovers that the STAT1/SH2B3/gp130/STAT3 signaling axis plays critical roles in promoting GBM progression and provides insight into new prognosis marker and therapeutic target in GBM.
RESUMO
The mortality rate of patients with glioma is increasing worldwide per annum. This is attributed to the poor disease prognosis, most notably for highgrade gliomas (grade III and IV), which does not improve the overall patient survival. The dysregulation of microRNA (miRNA/miR)1243p is found in a variety of tumors. However, the association between miR1243p expression and its target genes in glioma has not been thoroughly elucidated. The present study aimed to explore the possible effects of miR1243p and its proved target, Ras homology Growthrelated (RhoG), on the oncogenic events associated with glioblastoma multiforme (GBM) development. The data demonstrated an inverse association between miR1243p and RhoG expression levels during GBM progression in GBM tissues and cells. U87 and U251 cells were employed for the in vitro assays. Luciferase reporter assays revealed that miR1243p interacted with RhoG at the RhoG 3' untranslated region and inhibited RhoG expression in GBM cells. Functionally, enriched miR1243p repressed RhoG transcription and suppressed GBM cell proliferation and migration, promoting apoptosis and altering the expression or activity of the apoptosisrelated proteins of GBM cells. By contrast, the inhibition of miR1243p in GBM cells upregulated RhoG levels and promoted the proliferation of GBM cells. The knock down of RhoG expression by specific small interfering RNA sequences partially neutralized the effects induced by the miR1243p inhibitor. In conclusion, the present study demonstrated the crucial effects of miR1243p on the development and deterioration of GBM by targeting RhoG.