IRF3 drives replication stress signaling and determines sensitivity to genotoxic agents in triple-negative breast cancer cells

Interferon-β signaling has been shown to play important roles in anti-virus as well as anti-tumor immunity. We here report that the key transcription factor in type I interferon signaling, IRF3, as well as downstream interferon-β are able to induce replication stress signaling in triple-negative breast cancer cells. IRF3 overexpression sensitizes triple-negative breast cancer cells to several genotoxic agents. Addition of IFN-β, a key downstream cytokine of IRF3,reduced replication fork speed and activated ATR-CHK1 signaling. Conversely, type I interferon-neutralizing antibodies or nucleosides supplementation rescued IRF3-induced replication stress.