The regulation of molecular apocrine genes by the AR-ERK feedback loop. (A) Heat map of top ranking molecular apocrine-signature genes following the inhibition of AR-ERK signaling using qPCR data. Heat map shows fold changes for gene expression relative to control in MDA-MB-453 and HCC-1954 cell lines. Treatments were carried out by CI-1040 (CI) at 2 µM and 10 µM concentrations, flutamide (FLU) at 25 nM and 40 nM concentrations, and the combination of flutamide at 25 nM or 40 nM and CI-1040 at 2 µM concentrations. Red and green colors depict up-regulation and down-regulation, respectively. Bar indicates the range of fold changes in gene expression. (B) Box plots to demonstrate relative expression of PIP to control following AR-ERK inhibition in MDA-MB-453 and HCC-1954 cell lines using qPCR. CTL: control. (C) Western blot analysis to assess PIP protein levels following AR-ERK inhibition in MDA-MB-453 and HCC-1954 cell lines. Fold changes (RR) in band densities were measured relative to the control (CTL). AR, androgen receptor; ERK, extracellular signal-regulated kinase; qPCR, quantitative PCR; RR, relative risk.