Fig. 7.

IDO1 metabolite kynurenine and integrin β1 mediate the positive feedback of IDO1-MAPK-COL12A1. a After knockdown of IDO1 by siRNA for 48 h, SGC-7901 cells were treated by 10 μM L-kynurenine. After forcing expression of IDO1 by overexpressing eukaryotic plasmid for 48 h, HGC-27 cells were treated by 1 μM SR1. Forty eight hours later, Western blot was used to examine expression of IDO1, COL12A1 and phosphorylated ERK. b After knockdown of IDO1 by siRNA or up-regulation of IDO1 by overexpressing eukaryotic plasmid for 48 h, SGC-7901 and HGC-27 cells were treated by 10 μM L-kynurenine or 10 μM SR1 respectively. Forty eight hours later, transwell assay was performed to evaluate migration capacity of GC cells. “*” represented comparing with Con group, and “#” represented comparing with siIDO1 or IDO1 group. c-d COL12A1 was knocked down by siRNA for 48 h, and then integrin β1 was upregulated by overexpressing eukaryotic plasmid for 48 h in SGC-7901 and HGC-27. Western blot was performed to detect IDO1, COL12A1 and phosphorylated ERK, and transwell assay was conducted to evaluate migration capacity of GC cells. “*” represented comparing with Con group, and “#” represented comparing with integrin β1 group. e-f SGC-7901 was treated by integrin β1 antibody (3 μg/ml) for 48 h. After IDO1 upregulated by overexpressing eukaryotic plasmid for 48 h, HGC-27 was treated by integrin β1 antibody (3 μg/ml) for 48 h. Expression of IDO1, COL12A1 and phosphorylated ERK was detected by Western blot. GC cell migration ability was evaluated by transwell assay. “*” represented comparing with control group, and “#” represented comparing with IDO1 group. *P < 0.05, **P < 0.01, ***P < 0.001. ##P < 0.01, ###P < 0.001