TIPE2 Suppresses Gastric Cancer Cell Migration And Invasion Via Negatively Regulating β-Catenin Signaling

Objective:To investigate whether tumor necrosis factor-alpha-induced protein 8-like 2(TNFAIP8L2, TIPE2) is capable of suppressing gastric cancer cell migration and invasion via downregulating β-catenin signaling.Methods: The adenovirus expressing human TIPE2 and marker gene green fluorescent protein(GFP)(Ad VTIPE2) and blank adenovirus expressing GFP(Ad V) was abundantly amplified in 293 human embryo kidney cells and purified by cesium chloride(Cs Cl) density-gradient ultracentrifugation. The adenoviral titre was then determined according to GFP expression in 293 cells by limiting dilution analysis. After the Ad VTIPE2’s or Ad V’s infection of AGS(wild-type p53) and HGC-27(mutant p53) human gastric cancer cells with an optima dose of 10 MOI(multiplicity of infection), the AGS-Ad VTIPE2(termed AGS-TIPE2) vs AGS-Ad V(termed AGS-Mock); and HGC-27-Ad VTIPE2(termed HGC-27-TIPE2) vs HGC-27-Ad V(termed HGC-27-Mock) gastric cancer cells were obtained. The adenovirus-mediated TIPE2 expression in AGS and HGC-27 gastric cancer cells was determined by reverse transcription-polymerase chain reaction(RT-PCR) and Western blot. The effect of adenovirus-directed TIPE2 overexpression on AGS and HGC-27 gastric cancer cell migration and invasion was evaluated by wound healing assay and Transwell chamber invasion assay, respectively. The effect of TIPE2 on expression of AKT-GSK3β-β-catenin axis-related proteins including p-AKT, AKT, p-GSK3β, GSK3β and β-catenin in AGS gastric cancer cells was analyzed by Western blot. The effect of TIPE2 on β-catenin was further performed by confocal microscopy analysis of immunofluorescence.Results: 1) The purified Ad VTIPE2(6.3X1010 Tu/ml) and Ad V(1.2X1011 Tu/ml) adenovirus with high titre were obtained; 2) Adenovirus-directed TIPE2 overexpression was capable of inhibiting AGS and HGC-27 gastric cancer cell migration(relative migratory ability, 64.8% of AGS-Mock and 78.6% of HGC-27-Mock) and invasion(relative invasive ability, 52.7% of AGS-Mock and 69.0% of HGC-27-Mock); 3) TIPE2 significantly downregulated the total level of p-AKT, p-GSK3β and β-catenin as well as inhibited the translocation of β-catenin from cytoplasm to nucleus and downregulated the nuclear level of β-catenin.Conclusions: TIPE2 suppresses gastric cancer metastasis via downregulation of β-catenin signaling very possibly via modulation of AKT-GSK3β-β-catenin axis.