Figure 1. ERG suppresses PI3K signaling constraining tumorigenesis.

A) Rosa26-ERG (n=10), Pten−/− (n=10) and Rosa26-ERG Pten−/− (n=10) prostate organoids were injected into the flanks of SCID mice and tumor volumes were measured weekly, error bars reporting standard deviation from the mean. B) Histology (200x) of in vivo specimens from the prostate organoids at the end of study. C) Prostate organoids were generated from Wild-type, Rosa26-ERG, Pb-Cre Pten^lox/lox and Pb-Cre Rosa26-ERG Pten^lox/lox mice and western blot analysis was performed demonstrating expression of ERG, loss of Pten, and repressed PI3K signaling in organoids over-expressing ERG (experiment run in triplicate). D) Analysis of the TCGA profiling data set demonstrating that ERG positive human primary prostate cancers are significantly correlated with a repressed AKT gene signature and loss of PTEN results in activation of this signature.