Harnessing DNA replication stress to target RBM10 deficiency in lung adenocarcinoma

The splicing factor RBM10 is frequently mutated in lung adenocarcinoma (LUAD) (9-25%). Most RBM10 cancer mutations are loss-of-function, correlating with increased tumorigenesis and limiting targeted therapy efficacy in EGFR-mutated lung cancer. Notably, therapeutic strategies leveraging RBM10 deficiency remain unexplored. Hence, we conducted RBM10 CRISPR-Cas9 synthetic lethality (SL) screen and identified ∼250 RBM10 SL genes, including WEE1 kinase. WEE1 inhibition sensitized RBM10-deficient LUAD cells in-vitro and in-vivo . Mechanistically, we identified a splicing-independent role of RBM10 in promoting replication fork progression that underpins RBM10-WEE1 SL. Also, we revealed that RBM10 is associated with active replication forks, which is reliant on PRIM1, an enzyme synthesizing RNA primers for Okazaki fragments. Functionally, we demonstrated that RBM10 serves as an anchor for recruiting HDAC1 and facilitates H4K16 deacetylation to maintain replication fork stability. Collectively, our data revealed a hitherto unrecognized function of RBM10 in fine-tuning DNA replication, and provide therapeutic arsenal for targeting RBM10-deficient tumors.