HIF-α activation by the prolyl hydroxylase inhibitor roxadustat suppresses chemoresistant glioblastoma growth by inducing ferroptosis

Patients with glioblastoma (GBM) have poor prognosis and limited treatment options, largely due to therapy resistance upon the induction of apoptosis. Ferroptosis emerges as a potential antineoplastic strategy to bypass apoptosis resistance in traditional therapeutics. Hypoxia is a fundamental hallmark of GBM and hypoxia-inducible factor (HIF) is the main regulator of hypoxia response, however, the role of HIF has not been sufficiently explored in GBM. Herein, we first discovered that amplifying HIF signals by the prolyl hydroxylase (PHD) inhibitor roxadustat significantly suppressed GBM cell growth in vitro and in vivo, especially when the cells were resistant to temozolomide (TMZ). The accumulation of lipid peroxidation and cellular iron in GBM cells following roxadustat treatment indicated that the cells underwent ferroptosis, which was also supported by morphological changes in mitochondrial ultrastructure and immunogenic signals release. Moreover, in vivo studies further confirmed the ferroptosis induction and verified that roxadustat significantly prolonged survival of the mice harboring chemoresistant GBM without visible organ toxicity. Finally, we proved that the ferroptosis induction by roxadustat is HIF-α independent, especially activation of HIF-2α upregulating lipid regulatory genes was revealed to be mainly responsible for the enhanced lipid peroxidation. Altogether, our study provided novel evidence that amplifying HIF signals induced ferroptosis in chemoresistant GBM cells and suppressed the tumor growth in vivo, highlighting that ferroptosis induction by targeting HIF-α might provide new approaches to improve GBM treatment.