N-phenylmaleimide induces bioenergetic switch and suppresses tumor growth in glioblastoma tumorspheres by inhibiting SLC25A11.

Background: Glioblastoma (GBM) is a highly resistant tumor, and targeting its bioenergetics could be a potential treatment strategy. GBM cells depend on cytosolic nicotinamide adenine dinucleotide (NADH), which is transported into the mitochondria via the malate-aspartate shuttle (MAS) for ATP production. N-phenylmaleimide (KN612) is a MAS inhibitor that targets SLC25A11, an antiporter protein of the MAS. Therefore, this study investigated the effects of KN612 in GBM treatment using in vitro and in vivo models.

Methods: We examined the biological effects of KN612 in GBM tumorspheres (TSs), including its effects on cell viability, ATP level, cell cycle, stemness, invasive properties, energy metabolic pathways, and transcriptomes. Additionally, we investigated the in vivo efficacy of KN612 in a mouse orthotopic xenograft model.

Results: Transcriptomic analysis showed that SLC25A11 mRNA expression was significantly higher in GBM TSs than in normal human astrocytes. Additionally, siRNA-mediated SLC25A11 knockdown and KN612-mediated MAS inhibition decreased the oxygen consumption rate, ATP levels, mitochondrial activity, and cell viability in GBM TSs and decreased the stemness and invasion ability of GBM cells. Moreover, gene ontology functional annotation indicated that KN612 treatment inhibited cell-cycle and mitotic processes. Furthermore, KN612 treatment reduced tumor size and prolonged survival in an orthotopic xenograft model.

Conclusions: Targeting GBM bioenergetics using KN612 may represent a novel and effective approach for GBM treatment.