Interferon- and STING-independent induction of type I interferon stimulated genes during fractionated irradiation

• Published in: Journal of experimental & clinical cancer research Vol. 40; no. 1; pp. 161 - 14
• Main Authors: Goedegebuure, Ruben S A, Kleibeuker, Esther A, Buffa, Francesca M, Castricum, Kitty C M, Haider, Syed, Schulkens, Iris A, Ten Kroode, Luuk, van den Berg, Jaap, Jacobs, Maarten A J M, van Berkel, Anne-Marie, van Grieken, Nicole C T, Derks, Sarah, Slotman, Ben J, Verheul, Henk M W, Harris, Adrian L, Thijssen, Victor L
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 08.05.2021; BioMed Central; BMC
• Subjects: Analysis; Animals; Astrocytoma - genetics; Astrocytoma - immunology; Astrocytoma - metabolism; Astrocytoma - radiotherapy; Biological response modifiers; Biopsy; Cancer; Cancer therapies; Care and treatment; Cell Line, Tumor; Colonic Neoplasms - genetics; Colonic Neoplasms - immunology; Colonic Neoplasms - metabolism; Colonic Neoplasms - radiotherapy; DNA microarrays; Dose Fractionation, Radiation; Drug dosages; Enzyme-linked immunosorbent assay; Esophageal cancer; Esophageal Neoplasms - genetics; Esophageal Neoplasms - immunology; Esophageal Neoplasms - metabolism; Esophageal Neoplasms - radiotherapy; Female; Gene expression; Gene Expression Regulation, Neoplastic - radiation effects; Genes; Genetic research; Genotype & phenotype; HT29 Cells; Humans; Immune response; Immunity - radiation effects; Interferon; Interferon Type I - genetics; Interferon Type I - immunology; Interferon Type I - metabolism; Laboratories; Membrane Proteins - genetics; Membrane Proteins - immunology; Membrane Proteins - metabolism; Mice; Mice, Inbred BALB C; Mice, Nude; Quality control; Radiation therapy; Radiotherapy; Random Allocation; RNA sequencing; Type I interferons; Xenograft Model Antitumor Assays; England; Radiotherapy; Immune response; Type I interferons
• ISSN: 1756-9966; 0392-9078; 1756-9966
• DOI: 10.1186/s13046-021-01962-2

Improvement of radiotherapy efficacy requires better insight in the dynamic responses that occur during irradiation. Here, we aimed to identify the molecular responses that are triggered during clinically applied fractionated irradiation. Gene expression analysis was performed by RNAseq or microarray analysis of cancer cells or xenograft tumors, respectively, subjected to 3-5 weeks of 5 × 2 Gy/week. Validation of altered gene expression was performed by qPCR and/or ELISA in multiple cancer cell lines as well as in pre- and on-treatment biopsies from esophageal cancer patients ( NCT02072720 ). Targeted protein inhibition and CRISPR/Cas-induced gene knockout was used to analyze the role of type I interferons and cGAS/STING signaling pathway in the molecular and cellular response to fractionated irradiation. Gene expression analysis identified type I interferon signaling as the most significantly enriched biological process induced during fractionated irradiation. The commonality of this response was confirmed in all irradiated cell lines, the xenograft tumors and in biopsies from esophageal cancer patients. Time-course analyses demonstrated a peak in interferon-stimulated gene (ISG) expression within 2-3 weeks of treatment. The response was accompanied by a variable induction of predominantly interferon-beta and/or -lambda, but blocking these interferons did not affect ISG expression induction. The same was true for targeted inhibition of the upstream regulatory STING protein while knockout of STING expression only delayed the ISG expression induction. Collectively, the presented data show that clinically applied fractionated low-dose irradiation can induce a delayed type I interferon response that occurs independently of interferon expression or STING signaling. These findings have implications for current efforts that aim to target the type I interferon response for cancer treatment.