GSE184624
TMPRSS2-ERG and gain-of-function p53 mutants co-dictate pyrimidine synthesis and prostate cancer fitness [RNA-seq-2018 ERG-p53 project]
TMPRSS2-ERG fusion is the most common genetic alteration in prostate cancer (PCa) and TP53 is the most frequently mutated gene in human cancers. However, their precise roles in PCa pathogenesis remain elusive. Here we showed that TMPRSS2-ERG fusion co-occurred with TP53 deletion/mutation in PCa patient specimens. ERG overexpression and Trp53 knockout/R172H mutant knockin induced pyrimidine synthesis gene (PSG) expression and prostate tumorigenesis in mice. Gain-of-function p53 mutants bound to the CTNNB1 promoter and upregulated ß-Catenin. Overexpressed ERG and ß-Catenin co-occupied PSG loci and mediated PSG expression, and high PSG expression associated with increased ß-Catenin level and poor overall survival of PCa patients. ß-Catenin inhibition by proteolysis-targeting chimeras (PROTACs) of its co-activator CBP and partner proteins LEF1/TCFs blocked ERG/p53-mutant PCa growth. Our study identifies CTNNB1 as a transcriptional target of p53 GOF-mutants, and reveals a druggable dependency on ß-Catenin and pyrimidine synthesis in p53-mutated cancers with or without TMPRSS2-ERG fusion. Overall design: To find the genes differentially expressed in Pb-ERG;Trp53pcR172H/- mice