See also .
A Network visualization illustrating path lengths from ERG to five candidate drugs forERG inhibition (dexamethasone, naproxen, acemetacin, ondansetron, epitiostanol). The node sizes correspond to the gene expression levels, with the larger size representing a higher expression level. If low expression genes are removed (RPKM<4), the path lengths for naproxen and acemetacin are increased while the paths from ondansetron and epitiostanol are completely disrupted. The corresponding table shows metrics that describe each of these drugs in relation to ERG: NES is the Normalized Enrichment Score obtained from GSEA, PL is the shortest network path length required to connect ERG to the drug, MI is the modulation index and MI * is modulation index respectively after low expression genes were removed (RPKM<4).
B Application of our method to dexamethasone expression profiles and ERG target genes. The (left) panel illustrates the results of the GSEA for ERG and dexamethasone. The lowest plot of the left panel shows the log2 differential expression profile for dexamethasone, with the ERG target genes marked directly above. Above are the running enrichment score and a histogram of the ERG target gene frequency, which illustrates whether the gene set is enriched in the under- or over-expression regions. The (middle) panel shows a subnetwork including all genes that were members of any shortest path between ERG and dexamethasone. The (right) panel illustrates our prediction that the application of dexamethasone would result in the downregulation of activity of ERG target genes.
C ERG target gene PLAU expression by RT-PCR in cell lines expressing ERG(DU145-ERG, VCaP) and controls (DU145-GFP) after treatment with vehicle or dexamethasone. Data are shown as mean ± SEM. Asterisks indicate statistically significant differences by paired t test and n = 3 for each condition (*p < 0.05,**p < 0.01, ***p < 0.001, ns - not significant).
D Cell invasion and migration in cell lines expressing ERG (DU145-ERG) and controls (DU145-GFP). The data are shown as mean ± SEM and at n=4 representation 10x field of view. Asterisks indicate statistically significant differences by paired t test and n = 3 for each condition (*p < 0.05, **p < 0.01, ***p < 0.001, ns - not significant).
E The binding of ERG and a control (IgG) by ChIP-PCR at the promoter of its target gene PLAU and at a negative control (ARHGEF) in cell lines expressing ERG (DU145-ERG, VCaP). Data are shown as mean ± SEM. Asterisks indicate statistically significant differences by paired t test and n = 3 for each condition (*p < 0.05, **p < 0.01, ***p < 0.001, ns - not significant).