Super-enhancer inhibitors THZ2 and JQ1 reverse temozolomide resistance in glioblastoma by suppressing SE-driven SOX9 expression

Aim: Glioblastoma (GBM) is the most malignant grade of glioma, characterized by high recurrence, poor prognosis, and frequent chemoresistance. There is an urgent need for alternative treatment strategies. In this study, we evaluated the effects of THZ2, a covalent inhibitor targeting the super-enhancer (SE) component CDK7, on GBM growth and chemoresistance. We also used another SE inhibitor, JQ1, to further validate the inhibitory effects of targeting SEs in GBM, thereby providing new treatment strategies for patients. Methods: A variety of in vitro and in vivo assays were performed to explore the anti-GBM effects of SE inhibitors. We assessed the effects of SE inhibitors in combination with temozolomide (TMZ) on GBM cells and calculated the combination index. Additionally, CUT&RUN assays were conducted to examine protein-DNA interactions. Results: THZ2 inhibited the proliferation, migration, and invasion of GBM cells and induced cell cycle arrest and Apoptosis. Furthermore, both THZ2 and JQ1 exhibited synergistic antitumor effects when combined with TMZ in GBM cells. Notably, THZ2 reversed TMZ resistance in GBM cells by suppressing the expression of the SE-associated gene SOX9. We also found that SOX9, CDK7, and BRD4 interact with histone H3K27ac. Conclusion: Our findings demonstrate that SE inhibitors exert antitumor effects in GBM and act synergistically with TMZ. THZ2 may enhance chemosensitivity by downregulating the SE-related gene SOX9, and it holds promise as a novel therapeutic agent for GBM patients.

CDK7 inhibitor; Glioblastoma; SOX9; chemoresistance; super-enhancer.