eLife assessment
In this study, the authors developed a cell-based screening assay for the identification of small molecule inhibitors of nonsense-mediated decay (NMD). They used it to validate a novel small molecule SMG1 kinase inhibitor that inhibits NMD in cultured cells leading to the expression of neoantigens from NMD-targeted genes, and in vivo slows tumor growth of cells with a significant number of out-of-frame indel mutations. The conclusions are supported by convincing evidence, and the significance of this work consists in the development of a novel and very promising NMD inhibitor drug that acts as an inhibitor of the SMG1 NMD kinase and is suitable for use in animals. This is an important advance for the field, as previous NMD inhibitors were not specific, lacked efficacy, or were very toxic and hence not suitable for animal application.