FoxM1 Drives ADAM17/EGFR Activation Loop To Promote Mesenchymal Transition In Classic Glioma Population

Objective: To investigate the roles of FoxM1/ADAM17 in mesenchymal transition in glioma cells, and explore the activation mechanism of Fox M1/ADAM17/EGFR feedbak loop, which might provide new strategy for glioma treatment.Methods:(1) Expression levels of Fox M1, ADAM17 and mesenchymal markers(FN、N-ca、vimentin、YKL-40) were determined using qRT-PCR、Western blotting and immunofluorescence in glioma cells;(2) CCK8 and Colony formation assay were applied to assess the growth ability of cells with different treatments;(3) Wound healing assay, transwell migration assay and osteogenic, adipogenic differentiation assay were conducted to evaluate the migration abilities, the differentiation potentials and the mesenchymal transition of glioma cells with different treatments, respectively;(4) Dual-luciferase reporter assay and ChIP were used to explore the role of FoxM1 in ADAM17 transcriptional regulation;(5) Western blotting and transfection were used to analyze the expression of Fox M1/ADAM17/EGFR signaling loop, and illuminate the mechanism of mesenchymal transiton drived by FoxM1.Results:(1)Fox M1 and ADAM17 expression in U251 MG and U87 MG were significantly higher than that in SW1783 and LN229, mesenchymal markers expression were also significantly higher than that in SW1783 and LN229, there was a positive correlation between the expression of mesenchymal markers and FoxM1, ADAM17;(2)Fox M1 or ADAM17 overexpression enhanced the abilities of growth, migration and differentiation potential, the expression of mesenchymal markers were also increased in SW1783 and LN229. FoxM1 or ADAM17 down-regulation reduced the abilities of growth, migration and differentiation potential the expression of mesenchymal markers were also decreased in U251 MG and U87MG;(3)Overexpressed FoxM1 in SW1783 increased the expression of ADAM17, while downregulated Fox M1 in U87 MG decreased the expression of ADAM17, and Fox M1 overexpression strenghthened luciferase activity mediated by ADAM17 promoter, but the luciferase activity were reduced when mutating the site(s) of Fox M1 binding to ADAM17 promoter. The phenomenon of Fox M1 overexpression promoting mesenchymal transition could be inhited by ADAM17 down-regulation in SW1783 and LN229, and the phenomenon of Fox M1 down-regulation inhibiting mesenchymal transition could be reversed by ADAM17 overexpression in U251 MG and U87MG;(4)FoxM1 activates EGFR/AKT signaling pathway through ADAM17 and phosphorylates GSK3β(S9) in glioma cells;(5)ADAM17 phosphorylates and deactivates GSK3β(S9) via EGFR/AKT pathway, to maintain the high expression of Fox M1 in glioma cells.Conclusions:(1)Fox M1/ADAM17 promotes the growth of glioma cells;(2)FoxM1 promotes mesenchymal transition through ADAM17 in glioma cells;(3)FoxM1-drived ADAM17/EGFR feedback loop maintains the stability of FoxM1 in glioma cells. It is suggested that Fox M1 drives the activation of EGFR signaling to promote mesenchymal transition in glioma cells, which might throw light on glioma treatments.