Figure 4.

Activation of AR signaling by NEU3 via PI3K and MAPK pathway in LNCaP cells. (a) Effects of specific inhibitors of PI3K (LY294002) and MAPK (PD098059) on NEU-3-mediated increase in EGR-1, AR and PSA protein levels, as assessed by immunoblotting. The results are two representatives of four independent experiments. Quantitative data are presented as described in Figure 3. (b) Effects of silencing of PI3K and MAPKK on NEU-3-mediated increase in AR and PSA. The siRNAs for PI3K p110α and for MAPKK (MEK1/2) were separately introduced to block specifically these kinase expressions. Similar results were obtained in two independent experiments. (c) Increased phosphorylation of AKT and ERK by NEU3. (d) Increased expression of EGFR and ERBB2 by NEU3 as evaluated by RT–PCR (left panel) and immunoblotting (right panel), respectively. Enhanced phosphorylation of ERBB2 and ERK by NEU3 under androgen-depleted condition (left panel). (e) Phosphorylation of EGFR and ERK by NEU3 in the presence of EGF