STAT3 element in MMP-7 promoter is not required and STAT3 not sufficient for isoproterenol-induced MMP-7 expression. A, schematic representation of the plasmid pMMP-7mS containing three mutated STAT3 sites at the positions -255 to -245, -168 to -159 and -137 to -122. B, MGC-803 cells were co-transfected with pMMP-7mS and pRL-TK, starved, 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, HGC-27 and MGC-803 cells were stably transfected with pGeneSuppressor expressing STAT3 shRNA. The expression of STAT3 was analyzed by Western blot in HGC-27/STAT3-sh and MGC-803/STAT3-sh cells. D, MMP-7 promoter activities were assayed in MGC-803/STAT3-sh cells after stimulation with 10 μM isoproterenol for 0, 1, 2, 3, 6 or 9 h, respectively. E through G, HGC-27/STAT3-sh and MGC-803/STAT3-sh cells were stimulated with 2 μM or 10 μM isoproterenol, respectively. The expression of MMP-7 was analyzed by RT-PCR (E), real-time PCR (F) and Western blot (G).