Stress granule assembly represents a therapeutic vulnerability in super-enhancer-driven circMLB-mediated glioblastoma temozolomide resistance.

Resistance to temozolomide (TMZ) is a major driver of treatment failure and high mortality in patients with glioblastoma (GBM). However, the mechanisms underlying TMZ resistance, especially intrinsic resistance, remain incompletely elucidated. Through integrative multi-omics analyses, we identified a novel super-enhancer-driven circular RNA, circMLB, which is highly overexpressed in TMZ-R GBM. Both in vitro and in vivo studies robustly demonstrate that circMLB significantly enhances TMZ resistance in GBM. Mechanistically, the transcription factor PAF1 forms a protein complex with BRD4 that is enriched in the super-enhancer region, thereby upregulating circMLB expression. Furthermore, highly expressed circMLB directly binds to PKR, triggering stress granule assembly and ultimately reinforcing TMZ resistance in GBM. Importantly, we identified a novel PKR inhibitor, lurasidone, which synergizes with TMZ to exert potent anti-tumor activity against TMZ-R GBM in preclinical models. Our findings uncover a previously unrecognized SE-circMLB-PKR axis mediating intrinsic TMZ resistance and highlight the lurasidone-TMZ combination as a promising therapeutic strategy to surmount TMZ resistance in GBM.