Fig. 4

Activation of ERK1/2 was responsible for the up-regulation of MUC1 induced by CCL21-CCR7. a The activation of ERK1/2 and Akt pathway induced by CCL21, KYSE410 and Eca9706 cells were seeding into 6 well culture plate and starved overnight, then culture medium was replaced by serum free medium contained CCL21 (100 ng/ml) and incubated for 0, 15, 30, 45, 60 min. Then cells were harvested for immunoblotting; b Blocking CCR7 could suppress the activation of Akt and ERK1/2 pathway induced by CCL21 in KYSE410 and Eca9706; c, d Inhibiting activation of ERK1/2 but not Akt could suppress the up-regulation of MUC1-C protein. The starved KYSE410 and Eca9706 cells were pretreated by DMSO as controll, U0126 or MK2206 for 30 min, then cells were treated with PBS or CCL21 (100 ng/ml). For detecting p-ERK1/2, p-Akt and MUC1-C, cells were harvested after incubated with CCL21 for 15 min, 30 min and 24 h respectively; e Inhibiting ERK1/2 but not Akt could remarkably suppress the activity of MUC1 promoter, KYSE410 and Eca9706 cells transfected with MUC1-pGL2b plasmid were pretreated with DMSO as control, U0126 or MK2206 and then treated with PBS or CCL21 (100 ng/ml) for 12 h, then cells were harvested to detect the relative luciferase activity. Each datapoint represents the mean ± SD of three repeated experiments. *P < 0.05