Bip inhibition in glioma stem cells promotes radiation-induced immunogenic cell death

Tumor regression in sites distant to the irradiated field are thought to be associated with emission of damage-associated molecular patterns (DAMPs) molecules and generation of immunogenic cell death (ICD). Glioma stem cells (GSCs) are resistant to high doses of radiation, and ultimately select the outgrowth of a more aggressive tumor. This study showed high-dose IR triggered fewer DAMPs molecules exposure and release in GSCs comparing to matched non-GSCs. Downregulation of binding immunoglobulin protein (Bip) promoted IR-mediated endoplasmic reticulum stress to generate DAMPs molecules by PERK and IRE1-alpha phosphorylation, and increased dendritic cells mature and effector T lymphocytes activation. GSCs treated with Bip knockdown and IR efficiently prevented tumor generation, and reduced post-radiotherapy tumor recurrence. These data suggest that Bip plays a critical role in inhibition of IR-induced ICD in GSCs, and Bip inhibition may be a promising strategy on adjuvant therapy by ameliorating tumor immune microenvironment.