Figure 2

IGF-1 induces the activity of MMP-9 and MMP-2 via both PI3-K and MAPK pathways. Serum-deprived DU145 cells were pre-treated for 1 hour with either the PI3-K inhibitor wortmannin or the MEK inhibitor PD98059, then treated with IGF-1 for 24 hours in the same conditions of inhibitor use. The control consisted of adding a similar amount of the vehicle (1× PBS for IGF-1, DMSO for wortmannin or PD98059) for each addition in the test conditions. Conditioned media was concentrated, normalized to cell number and used for gelatin zymography. Protease activity is seen as clear digested bands at 92 kDa for MMP-9, at 72 kDa for MMP-2 and at 52 kDa for MMP-1 (A). Densitometric quantification indicates that MMP-9 activity is increased by IGF-1, with this increase prevented by either wortmannin or PD98059 (B). MMP-2 activity is also induced by IGF-1; presence of either inhibitor completely abrogates this activation (C). The activity of MMP-1 is unaffected by IGF-1 both in the absence and presence of wortmannin or PD98059 (D).