Figure 7.

HSP27 mediates cross-talk between membrane-associated and nuclear-destined AR. A, KIF5B-tail blocks androgen-induced phosphorylation of HSP27. LNCaP cells transfected with KIF5B-tail or KIFC3-tail were treated with 1 nm R1881 for 15 and 25 min, and analyzed by Western blotting for total and phosphorylated HSP27. B, AR–WT, but not AR–C807A, induces HSP27 phosphorylation. COS-7 cells transfected with AR–WT or AR–C807A were treated with 1 nm R1881 for 0, 10, 20 min, and analyzed by Western blotting for total and phosphorylated HSP27. C, rescue of TMPRSS2 expression by HSP27D. DU145 cells were transfected with AR–WT/AR–C807A with vector/HSP27A/HSP27D, and treated with EtOH or 1 nm R1881 for 24 h. Following qRT-PCR, normalized TMPRSS2 mRNA levels were expressed relative to the leftmost group. D, inhibition of androgen-induced PSA expression by 2-BP is rescued by constitutively active HSP27. LNCaP cells were transfected with HSP27A/HSP27D or empty vector, treated with 10 μm 2-BP or DMSO for 16 h, followed by 1 nm R1881 or EtOH treatment for an additional 24 h. Following qRT-PCR, normalized PSA mRNA levels (by RPL30 housekeeping gene) were expressed relative to the leftmost group. E, HSP27D rescued cell growth. DU145 cells were transfected with AR/AR–C807A with vector/HSP27A/HSP27D, cultured in RPMI supplemented with 10% cs-FBS and treated with 1 nm R1881 for 1 to 3 days, and the SRB assay was performed. The data were expressed as -folds of the day 0 readings. The mean ± S.D. from at least three experiments are plotted. *, p < 0.05.