MCM7 and AR interaction essential for AR transcriptional activity. A: Immunoblot analysis of MCM7 protein expression after 24 or 48 hours of treatment of R1881 at different dosages. Left: PC3+AR cells. Right: PC3+ΔAR cells. B: Semiquantitative RT-PCR on MCM7 (top) and β-actin (bottom) mRNA in LNCaP, PC3+AR, or PC3+ΔAR cells treated with or without 10 nmol/L R1881. cDNA templates of 2 μg of total RNA were diluted at the indicated titrations. PCRs were subsequently performed using primers specific to MCM7 or β-actin. C: Immunoblot analysis of COX-2 and GCNT3 expression in PC3+AR or PC3+ΔAR cells treated with (T) or without (U) 10 nmol/L R1881 (18 hours) and with siRNA specific for MCM7 (M7) or scramble (Scr). D: Knocking down MCM7 reducing AR-dependent promoter activities of PSA, GCNT3, and COX2 promoters in LNCaP cells. LNCaP cells were transfected with pLenti-mcs-GCNT3-bla or pLenti-mcs-COX2-bla or pLenti-mcs-PSA-bla vectors, treated with the indicated siRNA, and induced with or without 10 nmol/L R1881. β-Lactamase activities were quantified as percent of scramble controls. Five experiments were performed for each treatment. SD is indicated. siM7, siRNA for MCM7; scr, scramble siRNA. β-Lactamase activities of these cells were quantified and measured as the fold change of untreated controls. Inset: immunoblots of MCM7 and β-actin on LNCaP cells; U, untreated; Scr, scramble siRNA; siM7, siRNA specific for MCM7.