Abstract 6630: Non-cell-autonomous cancer progression from chromosomal instability

Abstract Chromosomal instability (CIN) is a driver of cancer metastasis, yet the extent to which this effect depends on the immune system remains unknown. Using ContactTracing—a newly developed, validated and benchmarked tool to infer the nature and conditional dependence of cell-cell interactions from single-cell transcriptomic data—we show that CIN-induced chronic activation of the cGAS-STING pathway promotes downstream signal re-wiring in cancer cells, leading to a pro-metastatic tumor microenvironment. This re-wiring is manifested by type I interferon tachyphylaxis selectively downstream of STING and a corresponding increase in cancer cell-derived endoplasmic reticulum (ER) stress response. Reversal of CIN, depletion of cancer cell STING or inhibition of ER stress response signaling abrogates CIN-dependent effects on the tumor microenvironment and suppresses metastasis in immune competent, but not severely immune compromised, settings. Treatment with STING inhibitors reduces CIN-driven metastasis in melanoma, breast and colorectal cancers in a manner dependent on tumor cell-intrinsic STING. Finally, we show that CIN and pervasive cGAS activation in micronuclei are associated with ER stress signaling, immune suppression and metastasis in human triple-negative breast cancer, highlighting a viable strategy to identify and therapeutically intervene in tumors spurred by CIN-induced inflammation. Citation Format: Jun Li, Melissa Hubisz, Ethan Earlie, Mercedes Duran, Christy Hong, Austin Varela, Emanuele Lettera, Matthew Deyell, Bernardo Tavora, Jonathan Havel, Phyu Su, Amit Dipak Amin, Karolina Budre, Erina Kamiya, Julie-Ann Cavallo, Christopher Garris, Simon Powell, Jorge Reis-Filho, Hannah Wen, Sarah Bettigole, Atif Khan, Benjamin Izar, Eileen Parkes, Ashley Laughney, Samuel Bakhoum. Non-cell-autonomous cancer progression from chromosomal instability abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 6630.