PLX171432

GSE107735: Hot-spot Mutations in RXRA Implicate Peroxisome Proliferator-Activated Receptors as Bladder Cancer Drivers

• Organsim human
• Type RNASEQ
• Target gene
• Project ARCHS4

RXRA regulates transcription as part of a heterodimer with 14 other nuclear receptors, including the peroxisome proliferator-activated receptors (PPARs). Analysis from the TCGA raised the possibility that hyperactive PPAR signaling, either due to PPAR gamma gene amplification or RXRA hot-spot mutation (S427F/Y) drives 20-25% of bladder cancers. Here we characterize mutant RXRA, demonstrating it induces enhancer/promoter activity in the context of RXRA/PPAR heterodimers. Structure-function studies indicate the RXRA substitution allosterically regulates the PPAR AF2 domain via an aromatic interaction with the terminal tyrosine found in PPARs. In urothelium, we find PPAR agonism is sufficient to drive growth factor independent growth, but only after deletion of the tumor suppressors Kdm6a and Trp53. Similarly, mutant RXRA stimulates growth factor independent growth, in a manner reversible by PPAR inhibition. These studies reveal a pro-tumorigenic interaction between loss of tumor suppressors and PPAR activation and implicate PPARs as targetable drivers of bladder cancer. SOURCE: Vivek,K,Arora (arorav@wustl.edu) - Washington University School of Medicine