(A) Effect of c-Jun overexpression on endogenous PSA level in LNCaP cells. LNCaP cells cultured in androgen-depleted medium for 24 hr, followed by transient transfection with empty vector (Vec) or plasmids encoding Flag-c-Jun (Jun). After 24 hr, cells were treated with 10 nM R1881 or the ethanol control (EtOH) for another 24 hr before harvesting for immunoblotting analysis of AR, PSA and Flag-c-Jun (Flag). (B) Time course of c-Jun induction on endogenous PSA protein expression in LNCaP cells. LNCaP-rtTA-c-Jun cells were treated with 100 ng/ml doxycycline (Dox) for indicated periods of time. AR, PSA and Flag-c-Jun (Flag) were immunoblotted. (C) Effect of LZ deletion on c-Jun-inhibited PSA expression in LNCaP cells. LNCaP-rtTA-c-Jun or c-JunΔLZ cells were treated with 100 ng/ml Dox for 24 hr. AR, PSA and Flag-c-Jun (Flag) were immunoblotted. (D) Wild-type but not LZ-deleted c-Jun efficiently suppresses androgen-induced PSA expression in LNCaP cells. LNCaP-rtTA-c-Jun or c-JunΔLZ cells were cultured in androgen-depleted medium for 24 hr, followed by induction of wild-type or mutant c-Jun with indicated concentrations of Dox. Twenty-four hours post c-Jun induction, cells were treated with 10 nM R1881 for another 24 hr. AR, PSA and Flag-c-Jun (Flag) were then immunoblotted. (E) to (I) Effect of c-Jun or c-JunΔLZ expression on steady state mRNA levels of PSA, KLK2,TMPRSS2, PCDH11 and UGT2B15 in LNCaP cells. LNCaP-rtTA-c-Jun or c-JunΔLZ cells were treated with 100 ng/ml Dox for 24 hr. Transcripts of PSA (E, n=4), KLK2 (F, n=3), TMPRSS2 (G, n=3), PCDH11 (H, n=3), and UGT2B15 (I, n=3) were determined by qRT-PCR. The single and the double asterisk indicate the P value between control (Con) and Dox groups is less than 0.05 and 0.001, respectively (Student’s t-test). (J) Effect of c-Jun knockdown on PSA expression in LNCaP cells. LNCaP-c-JunKD cells were treated with Dox (100 ng/ml) for 4 days followed by immunoblotting analysis of AR, PSA and c-Jun expression.