Cell proliferation was measured by cell counting. For this, transient SUB1 and PLK1 knockdown and stable cells overexpressing SUB1 were used. After 72 h of transfection using specific siRNA, the cells were trypsinized and seeded at a density of 10 000 cells per well in 24-well plates (n=3). Non-T siRNA-treated cells were served as controls. The stable RWPE lacZ- or SUB1-overexpressing cells were plated at the same density as mentioned earlier, trypsinized and counted at specified time points by Z2 Coulter particle counter (Beckman Coulter, Brea, CA, USA). Each experiment has been performed with three replicates per sample.