DDDR-20. FOSL1 INDUCES TMZ-CHEMORESISTANCE IN GLIOBLASTOMA VIA REGULATION OF IL-6-STAT3TYR705PATHWAY-MEDIATED STEMNESS

Abstract Glioblastoma (GBM) is the most lethal brain tumors with intensive resistance to drug. Although glioblastoma has been tried to treat with diverse strategies, drug resistance is still concerning. Finding new therapeutic targets to improve conventional drug sensitivity has remained a major challenge. Here, a novel therapeutic target, FOSL1, to conventional drug resistant patients was established, in which FOSL1 knockdown restores the temozolomide (TMZ) sensitivity via regulation of IL-6-induced stemness characteristic in glioblastoma cells. We show that FOSL1, contributing to poor prognosis of GBM patients, is closely linked chemo-resistant molecular signatures. In glioblastoma cells, FOSL1 knockdown is affect to apoptosis, G0/G1 arrest, tumor migration and expression of stemness hallmark. These alterations were induced by FOSL1-mediated IL-6-pSTAT3Tyr705 activation via MGMT independent manner. Finally, we show that vemurafenib, targeting FOSL1 expression, can be potential therapeutics for TMZ resistant glioblastoma. Taken together, our results demonstrate that FOSL1 facilitates TMZ chemoresistance via regulating IL-6-pSTAT3Tyr705-mediated stemness in GBM cells. FOSL1 can represent a novel therapeutic target to overcome GBM chemoresistance.