10020-CB-1 Effective Targeting of Glioma Stem Cells by BSJ–04–122, a Novel Covalent MKK4/7 Dual Inhibitor

Abstract Background/Aim Glioblastoma is a highly aggressive brain tumor characterized by poor prognosis and inevitable recurrence following standard therapy. Glioma stem cells (GSCs), a subpopulation with enhanced tumor–initiating potential and resistance to conventional treatments, are thought to drive tumor recurrence and progression. The c–Jun N–terminal kinase (JNK) signaling pathway plays a key role in maintaining the stem–like properties of GSCs. While JNK has emerged as a potential therapeutic target, the effectiveness of upstream targeting at the level of MKK4 and MKK7, the MAP2Ks that activate JNK, has not been fully explored in this context. ­Materials and Methods The effects of BSJ–04–122 on the viability of normal human fibroblasts and matched pairs of GSCs and their isogenic, differentiated counterparts as well as on the JNK activity, self–renewal (glioma stem cell marker expression and sphere–forming ability) and tumor–initiating capacity of GSCs were examined. Results At concentrations that did not affect the viability of normal fibroblasts, BSJ–04–122 effectively inhibited JNK activity and reduced the expression of stem cell markers in GSCs and induced cell death more efficiently in GSCs than in their differentiated counterparts. Furthermore, the capacity of GSCs that survived the BSJ–04–122 treatment to form spheres and initiate tumors was impaired. Conclusion BSJ–04–122 is a first–in–class covalent dual inhibitor of MKK4/7 that selectively targets GSCs by inhibiting JNK signaling, leading to cell death or loss of stem–like properties. These findings support a therapeutic strategy that combines BSJ–04–122 to eliminate GSCs with conventional therapies targeting non–stem glioblastoma cells, offering a rational and potentially effective approach for treating this aggressive brain tumor.