IGFBP5 increases survival of LX2 cells. (A) The viability of IGFBP5 overexpressing (LX2(BP5)) and control cells (LX2) cultured in serum-free medium for 48 h was measured using WST. (B) The viability of LX2 cells cultured in serum-free medium for 48 h was determined using WST. At t = 24 and 45 h, recombinant IGFBP5 was added (rBP5). (C) LX2 cells were transfected with small interfering control (siCtrl) or IGFBP5 siRNA (siBP5). At 16 h after transfection the medium was replaced by serum-free medium and 48 h later the viability of the cells was measured using WST. rIGFBP5 was added at t = 24 and 45 h of serum-free culturing (siBP5+rBP5). (D) Bromo-2'-deoxy-uridine (BrdU) incorporation was used to determine the proliferation of LX2 cells cultured in serum-free medium for 48 h. rIGFBP5 was added at t = 24 and 45 h (rBP5). BrdU was added at t = 32 h. The results are shown as percentage of the control cells.