Dickkopf-related protein 1/cytoskeleton-associated protein 4 signaling activation by Helicobacter pylori-induced activator protein-1 promotes gastric tumorigenesis via the PI3K/AKT/mTOR pathway

Figure 5 Dickkopf-related protein 1 promotes β-catenin and cytoskeleton-associated protein 4 expression and the binding of dickkopf-related protein 1 to cytoskeleton-associated protein 4 in gastric cancer tissues and cells but does not affect the nuclear translocation of β-catenin. A-C: Dickkopf-related protein 1 (DKK1) knockdown decreases β-catenin expression without changing β-catenin nuclear translocation in AGS cells, as determined using RT-qPCR (A), Western blotting (B), and immunofluorescence (C). Scale bar = 25 μm; ^aP < 0.05; D: RT-qPCR for β-catenin in AGS and BGC823 cells with DKK1 overexpression. ^aP < 0.05; E: β-catenin expression and its association with 10-year overall survival in gastric cancer (GC) samples of the TCGA-STAD database. ^cP < 0.001; F: Cytoskeleton-associated protein 4 (CKAP4) expression and its positive association with 10-year overall survival in GC samples of the TCGA-STAD database. ^dP < 0.0001; G: Immunohistochemical staining of CKAP4 in clinical GC tissues and matched normal tissues. The red arrow indicates CKAP4 expression in the cell membrane; H: CKAP4 staining quantification in G. Data from 12 independent samples are expressed as means ± SD. ^bP < 0.01; I: Western blotting for CKAP4 in GC cells with or without Helicobacter pylori (H. pylori) infection for 72 h; J: Co-IP of DKK1 and CKAP4 in BGC823 cells with and without H. pylori infection for 72 h. Con: Control; Hp: H. pylori. DKK1: Dickkopf-related protein 1; H. pylori: Helicobacter pylori; CKAP4: Cytoskeleton-associated protein 4; GC: Gastric cancer.