Isoproterenol up-regulates MMP-7 promoter activity and activates STAT3 and AP-1. A, schematic representation of the plasmid pMMP-7 containing a luciferase reporter gene driven by a 340 bp MMP-7 promoter fragment. SBE, STAT3 site; ABE, AP-1 site. B, MGC-803 cells were co-transfected with pMMP-7 and pRL-TK. After transfection for 48 h, the cells were incubated in serum-free medium for an additional 24 h and then stimulated with 10 μM isoproterenol for 0, 1, 2, 3, 6 or 9 h, respectively. MMP-7 promoter activities were assessed by luciferase assays. C and D, MGC-803 cells were treated with 10 μM propranolol for 1 h and then with 10 μM isoproterenol for 0, 15, 30, 60, 120 or 180 min, respectively. The phosphorylation of STAT3 and c-Jun was analyzed by Western blot with anti-phosphor-STAT3 and anti-phosphor-c-Jun rabbit polyclonal antibodies. ISO, isoproterenol.