Cell proliferation assay (a) and mitochondrial membrane depolarisation (MitoPotential) assay (b) between N87 cells transfected with an empty vector (N87-empty) and N87-oeGNG4 cells. Cell proliferation assay (c) and MitoPotential assay (d) between parental MKN1 and dGNG4-MKN1 cells. Cell cycle assay comparing MKN1 and dGNG4-MKN1 cells using colorimetric detection of the cell cycle phase (e). Drug-sensitivity assay to 5FU (f) and cell adhesion assay to solid matrices (g) comparing MKN1 and dGNG4-MKN1 cells. Capillary-based immunoassays of phospho-extracellular signal-regulated kinase 1/2 (ERK1/2) (Thr202/Tyr204), total ERK1/2, phospho-Akt (Ser473) and total Akt comparing MKN1 and dGNG4-MKN1 cells (h). p- indicates phosphorylated; t-, total. Mouse subcutaneous xenograft model (i) and liver metastatic model (j) comparing MKN1 and dGNG4-MKN1 cells. Tumour volume was evaluated with an in vivo spectrum imaging system (IVIS) at 4, 8 and 12 weeks after implantation (plotted chronologically in the lower panel) and by MRI at 12 weeks after implantation. Circles on the mice indicate regions of interest. *P < 0.05, **P < 0.01, ***P < 0.001.