De Novo Pyrimidine Synthesis Is a Collateral Metabolic Vulnerability in NF2-deficient Mesothelioma

Pleural mesothelioma (PM) is one of the deadliest cancers, with limited therapeutic options due to its therapeutically intractable genome, which is characterized by the functional inactivation of tumor suppressor genes (TSGs) and high tumor heterogeneity, including diverse metabolic adaptations. However, the molecular mechanisms underlying these metabolic alterations remain poorly understood, particularly how TSG inactivation rewires tumor metabolism to drive tumorigenesis and create metabolic dependencies. Through integrated multi-omics analysis, we identify for the first time that NF2 loss of function defines a distinct PM subtype characterized by enhanced de novo pyrimidine synthesis, which NF2-deficient PM cells are critically dependent on for sustained proliferation in vitro and in vivo. Mechanistically, NF2 loss activates YAP, a downstream proto-oncogenic transcriptional coactivator in the Hippo signalling pathway, which in turn upregulates CAD and DHODH, key enzymes in the de novo pyrimidine biosynthesis pathway. Our findings provide novel insights into metabolic reprogramming in PM, revealing de novo pyrimidine synthesis as a synthetic lethal vulnerability in NF2-deficient tumors. This work highlights a potential therapeutic strategy for targeting NF2-deficient mesothelioma through metabolic intervention.