TMEM164 enhances radioresistance of GBM cells by inhibiting the FASN-NADPH-ROS axis.

Purpose: Glioblastoma multiforme (GBM), one of the most aggressive primary brain malignancies, remains a major therapeutic challenge in contemporary neuro-oncology. Radiotherapy, an essential component of current standard therapeutic protocol, still has persistently poor clinical efficacy in the intrinsic radioresistance of GBM. Therefore, elucidating the underlying mechanisms of radioresistance is critical for optimizing therapeutic outcomes in GBM patients.

Methods: Radioresistant GBM cell lines U251R were established by irradiating U251 cells with fractionated dose of 60 Gy in total. RNA-seq and TMT assays were applied, combined with GEO, KEGG and other databases to analyze the role of TMEM164 in regulating the radiosensitivity of GBM cells. Pharmacological inhibition of cell death pathways was employed to identify the predominant cell death mechanism influencing TMEM164-mediated radioresistance in GBM cells. The intracellular levels of NADPH, lipid droplet and ROS were detected after radiation to assess the effect of TMEM164 on lipid metabolism. The effect of TMEM164 on necroptosis through FASN-NADPH-ROS axis was verified by rescue experiments.

Results: Through bioinformatics analysis, TMEM164 was identified as a key gene regulating GBM cells' radiosensitivity. Knockdown of TMEM164 significantly increased necroptosis in U251R and T98G cells. Integrated enrichment analysis of RNA-seq and TMT data revealed that FASN interacted with TMEM164. Excessive NADPH consumption led to intracellular ROS accumulation, thereby increasing radiosensitivity in GBM cells.

Conclusions: Our findings indicated that TMEM164 might serve as a critical biological target of GBM cells radioresistance, providing a novel theoretical basis for GBM radiotherapy.