Fig. 3

FBXO2 activates STAT3 signaling in OS dependent on its glycoprotein recognizing activity. a U2OS cells were transfected with the indicated plasmids for 36 h and then cells were lysed for luciferase assay. The results are indicated as fold induction of luciferase activity from triplicate experiments. ***p < 0.001. b U2OS cells were transfected with FBXO2 plasmid for 36 h, cells were lysed for western blot analysis. c The mRNA levels of MCL1, XIAP and STAT3 in FBXO2 WT or KO U2OS cells. d The mRNA levels of MCL1, XIAP and STAT3 in U2OS cells transfected with or without FBXO2. e ChIP assay showed that overexpression of FBXO2 increased the binding of STAT3 to the promotors of both MCL1 and XIAP genes in U2OS cells. The enrichment efficiency of endogenous STAT3 protein was detected by western blot assay. f ChIP assay showed that in FBXO2 KO U2OS cells, the binding of STAT3 to the promotors of both MCL1 and XIAP genes was decreased. The enrichment efficiency of endogenous STAT3 protein was detected by western blot. g The diagram of FBXO2 WT and FBXO2 MUT. FBXO2 WT or FBXO2 MUT plasmids were transfected into U2OS FBXO2 KO cells for 36 h. h The cell growth curve and i the mRNA levels of MCL1 and XIAP in these cells