Genome-Wide CRISPR-Cas9 Screen Reveals Selective Vulnerability of RBM10-deficient Lung Adenocarcinoma to WEE1 Kinase Inhibition

Lung adenocarcinoma (LUAD) is the most common subtype of non-small cell lung cancer and the leading cause of cancer death worldwide. Even though various targeted therapies for LUAD have been in use, their effectiveness is relatively low due to the diversity of the disease and development of therapeutic resistance. Thus, there is a pressing need to develop novel therapeutic strategies to improve the clinical outcome of LUAD patients. Intriguingly, the splicing factor RBM10, which possesses tumor suppressor activity, is the most mutated splicing factor in LUAD as its mutations occur in ~18% all LUAD cases. Prompted by this, we hypothesize that RBM10-deficiency can be exploited for developing novel therapeutic strategies for targeting a subset of LUAD. Towards this, we performed a genome-wide RBM10 CRISPR-Cas9 synthetic lethal screen in HCC827 LUAD cell line and identified 221 high-scoring RBM10 synthetic lethal genes. Gene ontology analysis revealed that RBM10 synthetic lethal genes are enriched in cell cycle regulators and DNA replication stress genes. Concordantly, replication stress induction by hydroxyurea hypersensitizes RBM10-deficient LUAD cells and leads to the accumulation of DNA damage. Intriguingly, one of the high-scoring RBM10 synthetic lethal genes is the cell cycle regulator, WEE1. Mechanistically, pharmacological inhibition of WEE1 in RBM10-deficient cells leads to excessive replication stress, increased DNA damage, and unscheduled mitotic entry. Moreover, WEE1 inhibition exhibits single-agent anti-tumor activity in vitro and in RBM10-deficient xenograft model. Altogether, our data identify promising therapeutic targets for selective eradication of RBM10-deficient lung adenocarcinoma.