Fig. 5

MSC-secreted TGF-β2 activates the PI3K-AKT signaling pathway in GIST cells. Both conditioned medium and recombinant TGF-β2 protein activate the PI3K-AKT signaling pathway of GIST, and the TGF-β2 monoclonal antibody antagonizes these effects (A, B). After silencing receptor II in the TGF-β receptor complex on the surface of GIST cells (C), both conditioned medium and recombinant TGF-β2 protein failed to activate the PI3K-AKT pathway of GIST (D, G). The PI3K-AKT signaling pathway inhibitor Wortmannin was able to antagonize the activation of the PI3K-AKT signaling pathway by conditioned medium and recombinant TGF-β2 protein (E, F). All experiments were repeated at least thrice. Data are means ± SEM (n = 3 in each group) *p < 0.05; **p < 0.01