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Elife. 2017 Nov 16;6. pii: e30862. doi: 10.7554/eLife.30862.

Bladder-cancer-associated mutations in RXRA activate peroxisome proliferator-activated receptors to drive urothelial proliferation.

Author information

1
Department of Internal Medicine, Division of Oncology, Washington University School of Medicine, St Louis, United States.
2
Genome Technology Access Center, Washington University School of Medicine, St Louis, United States.
3
Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, United States.

Abstract

RXRA regulates transcription as part of a heterodimer with 14 other nuclear receptors, including the peroxisome proliferator-activated receptors (PPARs). Analysis from 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 human bladder cancers. Here, we characterize mutant RXRA, demonstrating it induces enhancer/promoter activity in the context of RXRA/PPAR heterodimers in human bladder cancer cells. Structure-function studies indicate that the RXRA substitution allosterically regulates the PPAR AF2 domain via an aromatic interaction with the terminal tyrosine found in PPARs. In mouse urothelial organoids, PPAR agonism is sufficient to drive growth-factor-independent growth in the context of concurrent tumor suppressor loss. Similarly, mutant RXRA stimulates growth-factor-independent growth of Trp53/Kdm6a null bladder organoids. Mutant RXRA-driven growth of urothelium is reversible by PPAR inhibition, supporting PPARs as targetable drivers of bladder cancer.

KEYWORDS:

KDM6A; PPARD; PPARG; RXRA; TP53; bladder cancer; cancer biology; human; mouse

PMID:
29143738
PMCID:
PMC5720590
DOI:
10.7554/eLife.30862
[Indexed for MEDLINE]
Free PMC Article

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