Fig. 3

sFRP1 augments an autocrine feedback loop of Wnt16B/β-catenin signaling in HCC cells. a Downregulation of β-catenin by siRNA (siβ-catenin) significantly suppressed sFRP1-induced EMT, c-Myc, cyclin D1 and Nanog expression in HCC cells. b The mRNA and protein expression levels of Wnt16B were significantly increased in HCC cells treated with exogenous sFRP1 (0, 0.5,1.0 μg/mL), as detected by qRT-PCR and western blot analyses. c EMT-related markers (E-cadherin, N-cadherin, vimentin and snail) were assessed in HCC cells treated with sFRP1 alone or sFRP1 (1.0 μg/mL) and Wnt16B (0.5 μg/mL). d Nuclear β-catenin in HCC cells treated with sFRP1 (1.0 μg/mL) alone or sFRP1 and Wnt16B (0.5 μg/mL) were detected by immunofluorescence assays. e Wnt16B binding to FZD7 was significantly increased in the presence of sFRP1, as indicated by immunoprecipitation assay. It demonstrated that level of Wnt16B interacted with FZD7 was significantly upregulated in HCC cells in the presence of sFRP1, suggesting that sFRP1 strengthens FZD7 interaction with Wnt16B. f Downregulation of β-catenin by siRNA (siβ-catenin) significantly diminished sFRP1-induced Wnt16B promoter activity in HCC cells. g Over-expression of TCF4 enhanced Wnt16B promoter activity in HCC cells, which was inhibited by the downregulation of β-catenin (siβ-catenin). *P < 0.05, **P < 0.01, *** P < 0.001