Modulation of IGFBP5 expression in LX2 cells. (A) IGFBP5 mRNA levels in control cells (LX2) and in cells with lentiviral overexpression of IGFBP5 (LX2(BP5)). RNA levels normalized to 36B4 are shown as a percentage of control cells. (B) IGFBP5 protein levels in control (LX2) and transduced (LX2(BP5)) cells as demonstrated on a Western blot (upper panel) and quantified using the LumiImager (lower panel). (C) Silencing of IGFBP5 expression. Cells were transfected with small interfering (si) RNA for IGFBP5 (siBP5) or with a control siRNA (siCtrl). RNA was isolated 48 h later and IGFBP5 mRNA levels were quantified, normalized to 36B4 and given as a percentage of control cells. (D) Proteins were isolated from the cells and the medium 48 h after small interfering RNA (sRNA) transfection. The presence of IGFBP5 protein was visualized by Western blotting in LX2 and LX2(BP5) cells transfected with control siRNA (siCtrl) and IGFBP5 siRNA (siBP5) and in medium obtained from transfected LX2(BP5). The results are given as a percentage of the control cells. The error bars represent standard deviations, with asterisks denoting significant difference (P < 0.05).