The siRNA duplexes (duplex 1, cat. no. SI04174835 and duplex 2, cat. no. SI00678580) used to inhibit SUB1 expression were purchased from Qiagen, and PLK1 SiGenome SMARTpool (cat. no. M-003290-01-0005) was purchased from GE Dharmacon (Lafayette, CO, USA). Precursors of respective microRNAs and negative controls were purchased from Ambion (Life Technologies). Transfections were performed either with oligofectamine or Lipofectamine RNAiMAX (Life Technologies). SUB1 shRNA (pGipz SUB1-shRNA 1 (V2LHS_85556) and SUB1-shRNA2 (V3LHS_331788)) were purchased from GE Dharmacon. Lentiviruses for these stable knockdowns were generated by the University of Michigan Vector Core. For miRNA transfection or RNA inference, we plated prostate cancer cells at 1 × 105 cells per well in a 6-well plate, and after 12 h, the cells were transfected either with siRNA duplexes or miRNAs. A second identical transfection was performed 24 h later. Seventy-two hours after the first transfection, cells were harvested for RNA isolation or immunoblot analysis.