Figure 5.

Functional involvement of STAT3 and ERK pathway in Ras (G12V)‐induced activation of ST2 promoter. (A) NIH‐3T3 cells were transfected with plasmids harboring Ras (G12V) and the indicated luciferase vectors. Then, to test the functional involvement of Ras‐related signaling molecules and STAT3, cells were treated with/without STAT3 inhibitor, 50 nm Napabucasin (STAT3i). Forty‐eight hours later, the cells were harvested, and promoter activity was evaluated by performing luciferase assays. (B) TM‐12 cells were transfected with reporter gene plasmids, and then 24 h later, cells were treated with indicated inhibitor compounds such as DMSO, 10 μm PD98059 or 10 μm SB203580. DMSO was utilized as a control. After 48 h, the cells were harvested, and promoter activity was evaluated by performing luciferase assays. (C) NIH‐3T3 cells were transfected with plasmids harboring Ras (G12V) and the indicated luciferase vectors. Then, cells were treated with the inhibitors indicated in (B). Forty‐eight hours later, the cells were harvested, and promoter activity was evaluated by performing luciferase assays. In the graph, error bar means standard deviation (SD, n = 3).