The effect of conditioned medium on ERK1/2 signalling in HUVECs. (A) HUVECs were treated with V CM (V) or P CM (P) for 0,5,10,15,20 and 30 minutes. (B) HUVECs were left untreated (U) or treated with V CM (V) or P CM (P) for 10 mins in the absence/presence of SU4984, PP2, PD98059 or LY294002. Cell lysates were subjected to immunoblot analysis using antibodies against phosphorylated ERK1/2 (top panel) and total ERK1/2 (bottom panel). A representative Western blot is displayed with a graph of semi-quantitative analysis of ERK1/2 phosphorylation determined as described in the Methods. (* represents statistical significance P < 0.05) Data are represented as mean ± SEM.