Abstract IA020: Micronuclei are a nexus of DNA damage signaling and genomic instability

Abstract

Abstract Micronuclei have classically been considered inert biomarkers of genomic instability arising from failed DNA damage repair and chromosome segregation errors in mitosis. Work from several groups including our own have now demonstrated that micronuclei are active contributors to the cellular response to DNA damage by driving chromothripsis and through induction of anti-viral gene expression programs mediated by the cGAS-STING pathway. We now show that the specific DNA damage type leading to micronuclei formation influences the capacity for cGAS localization and activation. This arises in part due to discrete chromatin features, present prior to DNA damage induction, that are retained in micronuclei several days after their formation. Together these data demonstrate that micronuclei connect the pre-damage chromatin status and the chromatin context of micronuclei-inciting lesions to the long-term signaling outcomes important for anti-tumor immunity. This finding implies that micronuclei represent archives for the nature of DNA repair failure and downstream signaling consequences. Based on this premise we will present our efforts in micronuclear proteomics where we uncover common features of micronuclei including splicing deficiencies. Such deficiencies presage exacerbated MN-associated DNA damage that is upstream of chromothripsis. These studies have direct implications for how cells sense the aftermath of DNA damage and how micronuclei contribute to ongoing genomic instability. Citation Format: Shane M. Harding. Micronuclei are a nexus of DNA damage signaling and genomic instability [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr IA020.