Endogenous Retrovirus Activation as a Key Mechanism of Anti-Tumor Immune Response in Radiotherapy.

Journal Article (Journal Article)

The generation of DNA double-strand breaks has historically been taught as the mechanism through which radiotherapy kills cancer cells. Recently, radiation-induced cytosolic DNA release and activation of the cGAS/STING pathway, with ensuing induction of interferon secretion and immune activation, have been recognized as important mechanisms for radiation-mediated anti-tumor efficacy. Here we demonstrate that radiation-induced activation of endogenous retroviruses (ERVs) also plays a major role in regulating the anti-tumor immune response during irradiation. Radiation-induced ERV-associated dsRNA transcription and subsequent activation of the innate antiviral MDA5/MAVS/TBK1 pathway led to downstream transcription of interferon-stimulated genes. Additionally, genetic knockout of KAP1, a chromatin modulator responsible for suppressing ERV transcription sites within the genome, enhanced the effect of radiation-induced anti-tumor response in vivo in two different tumor models. This anti-tumor response was immune-mediated and required an intact host immune system. Our findings indicate that radiation-induced ERV-dsRNA expression and subsequent immune response play critical roles in clinical radiotherapy, and manipulation of epigenetic regulators and the dsRNA-sensing innate immunity pathway could be promising targets to enhance the efficacy of radiotherapy and cancer immunotherapy.

Full Text

Duke Authors

Cited Authors

  • Lee, AK; Pan, D; Bao, X; Hu, M; Li, F; Li, C-Y

Published Date

  • April 2020

Published In

Volume / Issue

  • 193 / 4

Start / End Page

  • 305 - 317

PubMed ID

  • 32074012

Pubmed Central ID

  • PMC7359417

Electronic International Standard Serial Number (EISSN)

  • 1938-5404

Digital Object Identifier (DOI)

  • 10.1667/RADE-20-00013


  • eng

Conference Location

  • United States