DHODH is an independent prognostic marker and potent therapeutic target in neuroblastoma [RNA-seq]

Despite intensive therapy, children with high-risk neuroblastoma are at risk of treatment failure. We applied a multi-omic system approach to evaluate metabolic vulnerabilities in human neuroblastoma. We combined metabolomics, CRISPR screening and transcriptomic data across >700 solid tumor cell lines and identified dihydroorotate dehydrogenase (DHODH), a critical enzyme in pyrimidine synthesis, as a potential treatment target. Of note, DHODH inhibition is currently under clinical investigation in patients with hematologic malignancies. In neuroblastoma, DHODH expression was identified as an independent risk factor for aggressive disease, and high DHODH levels correlated to worse overall and event-free survival. A subset of tumors with the highest DHODH expression was associated with a dismal prognosis, with a 5-year survival of <10%. In xenograft and transgenic neuroblastoma mouse models treated with the DHODH inhibitor brequinar, tumor growth was dramatically reduced, and survival was extended. Furthermore, brequinar treatment was shown to reduce the expression of MYC targets in three different neuroblastoma models in vivo. A combination of brequinar and temozolomide was curative in the majority of transgenic TH-MYCN neuroblastoma mice, indicating a highly active clinical combination therapy. Overall, DHODH inhibition combined with temozolomide has therapeutic potential in neuroblastoma and we propose this combination for clinical testing. These samples represent tumor tissue of three neuroblastoma mouse models treated with the DHODH inhibitor brequinar. Three replicates from each experimental condition is included. The models used were: 1) SK-N-BE(2)C cell-line derived subcutaneous xenografts; 2) SK-N-AS cell-line derived subcutaneous xenografts; 3) tumor tissue from homozygous mice of the transgenic TH-MYCN neuroblastoma mouse model. Xenograft mice were given one dose of brequinar 50 mg/kg i.p. and tumor tissue was sampled after 24 and 72 hours; tumor tissue from untreated mice were used as control. TH-MYCN mice were treated with one dose of brequinar 50 mg/kg i.p and tumors sampled after 72 hours; tumor tissue from vehicle treated mice were used as control. In addition, we sampled three tumors from mice which suffered from disease relapse after 120 days of brequinar treatment.