Topology of cell-free DNA from tumour cells influences its immunogenicity in macrophages and dendritic cells <i>in vitro</i>

Abstract Activation of DNA-sensing pathways can induce an anti-tumour immune response, but the mechanisms by which tumour-derived cell-free DNA (cfDNA) activates pro-inflammatory signaling is not well-understood. In particular, topological features cfDNA that contribute to sensor activation in phagocytes are unknown. As such, we investigated how topology influences macrophages and dendritic cells. We treated a murine colon adenocarcinoma cell line (MC38) with chemotherapy (topotecan or staurosporine) for varying durations release. then harvested cfDNA, separated protected (membrane-bound) accessible (non-membranous) fractions, quantified nuclear mitochondrial abundance. The fractions were added RAW 264.7 bone marrow-derived cells (BMDCs), panel inflammatory markers was measured RT-qPCR. found from MC38 48h increased Il6expression 264.7, other elevated. Interestingly, both abundance directly correlated Il6expression. Surprisingly, did signalling BMDCs. These results demonstrate immunogenicity depends on its mechanistic origins, abundance, type it exposed. currently examining impact biophysical properties macrophage activation, as well elucidating sensing responsible inducing Our findings will help uncover role mediating immunity. E.Z. Malkin supported Frederick Banting Charles Best Canada Graduate Scholarship (FRN: FBD-175873) through CIHR. S.V. Bratman Gattuso-Slaight Personalized Cancer Medicine Fund at Princess Margaret Centre Dr. Mariano Elia Chair Head Neck Research University Health Network Toronto.