NIBAN2/FLII/RREB1 Axis Drives Glioma Stem Cell Malignancy via TLR3 Pathway Activation

Glioma stem-like cells (GSCs), characterized by self-renewal capacity, therapeutic resistance, and high tumorigenicity, are considered the fundamental drivers of glioma aggressiveness and recurrence. However, the core regulatory mechanisms underlying GSCs stemness maintenance remain unclear. In this study, we identified that the NIBAN2 is highly expressed in glioma tissues and GSCs, and its expression is closely associated with poor patient prognosis. Functional experiments demonstrated that NIBAN2 directly binds to Flightless I (FLII) and enhances its interaction with the transcription factor Ras-responsive element-binding protein 1 (RREB1), thereby promoting nuclear translocation. Together, the NIBAN2-FLII-RREB1 complex activates the Toll-like receptor (TLR3) signaling pathway, sustaining the stem-like phenotype and tumorigenic potential of GSCs. Further investigation revealed that RREB1 transcriptionally upregulates NIBAN2 and CD44, promoting the expression of the key glycolytic enzyme LDHA (Lactate Dehydrogenase A). This establishes a feed-forward signaling-transcription-metabolism axis driven by NIBAN2/FLII/RREB1, facilitating metabolic reprogramming. Multi-omics and metabolomic analyses confirmed that this loop enhances glycolytic flux to maintain GSCs' metabolic homeostasis. Drug screening identified the HIV protease inhibitor nelfinavir as a specific disruptor of the NIBAN2-FLII complex. When combined with the LDHA inhibitor FX11, it induced synergistic anti-tumor effects in organoid and patient-derived xenograft models, thereby significantly inhibiting tumor progression and prolonging survival. Clinical samples further confirmed the co-upregulation of NIBAN2, FLII, and RREB1 in GBM (Glioblastoma) tissues, which correlates with SOX2 and Ki-67 expression and poor prognosis. Collectively, this study, for the first time, reveals that NIBAN2 maintains GSCs stemness by activating FLII-RREB1 axis and TLR3 signaling, thereby establishing a feed-forward signaling-transcription-metabolism axis. This finding provides a novel strategy and potential targets for precise therapeutic intervention against glioma stemness.