Type I IFN Signaling Drives Responsiveness to Short Course Radiotherapy in a Murine Model of Rectal Cancer

Specific cell types from orthotopic murine rectal tumors were sequenced to explore the effect that short course radiotherapy has on the immune response. MC38-luc tumor cells were orthotopically implanted in the rectum of C57BL6 female mice. Tumors were irradiated using a small animal irradiator from days 9-13 post tumor implantation. Tumors were treated with 5Gy radiation therapy for 5 consecutive daily fractions. Some mice were treated with anti-IFNAR blocking antibody. Tumors were harvested on day 14 and individual cell populations includining CD8 T cells (CD45+ CD8+), cancer associated fibroblasts (CD45-, CD31- Podoplanin+, PDGFRa+, Ly6c+), and tumor cells (GFP+) were sorted and processed for RNA sequencing.