Emerging roles of ATR beyond DNA damage repair: orchestrating transcriptional reprogramming during epithelial-to-mesenchymal transition.

The ability of cancer cells to transition between epithelial and mesenchymal states, a process known as epithelial-to-mesenchymal transition (EMT), is a key driver of cancer metastasis and therapy resistance. While ataxia telangiectasia and Rad3-related (ATR) kinase was originally characterized as a responder to DNA damage and replication stress, recent discoveries implicate a critical role for ATR in EMT and metastasis. Two pivotal studies published in this issue of JCI provide key insights into how ATR intersects with EMT transcriptional reprogramming. Patel et al. demonstrated that ATR prevented R-loop accumulation at EMT-related gene loci, thereby facilitating the transcriptional reprogramming necessary for EMT as well as tumor growth and metastasis. Tu et al. further uncovered a role for ATR in ECM stiffness-induced EMT, which was associated with an immunosuppressive tumor microenvironment. Together, these studies highlight important therapeutic implications for ATR targeting in the context of metastasis and therapy resistance.