Indisulam targets RNA splicing and metabolism to serve as a novel therapeutic strategy for high-risk neuroblastoma

Neuroblastoma is the most common solid tumour in childhood and prognosis remains poor for high-risk cases despite the use of multimodal treatment. Analysis of public drug sensitivity data showed neuroblastoma lines to be particularly sensitive to indisulam, a molecular glue that selectively targets RNA splicing factor RBM39 for proteosomal degradation via DCAF15-E3-ubiquitin ligase. In neuroblastoma models, indisulam induced rapid loss of RBM39, accumulation of splicing errors and growth inhibition in a DCAF15- dependent manner. Integrative analysis of RNAseq and proteomics data highlighted a distinct disruption to cell cycle and metabolism. Metabolic profiling demonstrated metabolome perturbations and mitochondrial dysfunction resulting from indisulam. Complete tumour without relapse was observed in both xenografts and the Th-MYCN transgenic model of neuroblastoma after indisulam treatment, with RBM39 loss confirmed in vivo. Our data imply that dual targeting of metabolism and RNA splicing with anti-cancer sulphonamides such as indisulam is a promising therapeutic approach for high-risk neuroblastoma.