Long non-coding RNAs (lncRNAs) play vital roles in the pathobiology of glioblastoma multiforme (GBM). Though radiotherapy remains the most effective component of multiple therapies for patients with GBM, lncRNAs conferring GBM radioresistance are less unknown. Here, the present study identified that the antisense transcript of hypoxia-inducible factor-1 alpha (AHIF) was upregulated in GBM cells after radiotherapy. The deregulation of AHIF affected GBM cell clonogenic formation, DNA repair and apoptosis. Notably, knockdown of AHIF inhibited tumorigenesis after radiotherapy in vivo. Further biochemical analysis identified that AHIF regulated proteins associated with apoptosis after radiotherapy. Thus, the present data illustrate that suppression of AHIF increases radiosensitivity in GBM cells, which may be a potential diagnostic and therapeutic target for GBM patients. (C) 2018 Elsevier Inc. All rights reserved.