Fig 2: Expression of GPR137 is suppressed by infection with Lv-shGPR137. Analysis of GPR137 messenger RNA expression levels in (A) AGS cells and (B) MGC80-3 cells by reverse transcription-quantitative polymerase chain reaction in the non-infected, Lv-shCon and Lv-shGPR137 groups. GAPDH gene expression was used as the internal control. Analysis of GPR137 protein expression levels in (C) AGS cells and (D) MGC80-3 cells by western blot analysis in the non-infected, Lv-shCon and Lv-shGPR137 groups. GAPDH was used as a loading control. Values are presented as the mean ± standard deviation (n=3). *P<0.05, **P<0.01 vs. Lv-shCon. GPR137, G protein-coupled receptor 137; Con, control; Lv-shCon, control lentivirus; Lv-shGPR137, GPR137 short hairpin RNA-expressing lentivirus.

Fig 3: GPR137 knockdown suppresses the proliferation of gastric cancer cells. The proliferation of (A) AGS cells and (B) MGC80-3 cells in the Lv-shGPR137 groups was significantly inhibited, as detected by MTT assay. Values are presented as the mean ± standard deviation (n=3). ***P<0.001 vs. Lv-shCon. GPR137, G protein-coupled receptor 137; Con, control; Lv-shCon, control lentivirus; Lv-shGPR137; GPR137 short hairpin RNA-expressing lentivirus; OD, optical density.

Fig 4: Knockdown of GPR137 arrests the cell cycle of MGC80-3 cells. (A) Cell cycle distribution in the Con, Lv-shCon and Lv-shGPR137 groups, evaluated by flow cytometry. (B) Cell percentage in distinct cell cycle stages varied between each group. Values are presented as the mean ± standard deviation (n=3). *P<0.05 vs. Lv-shCon. GPR137, G protein-coupled receptor 137; Con, control; Lv-shCon, control lentivirus; Lv-shGPR137; GPR137 short hairpin RNA-expressing lentivirus.

Fig 5: Determination of infection efficiency in human gastric cancer cells. Representative images of (A) AGS cells and (B) MGC80-3 cells following 96 h of lentivirus infection are shown (magnification, ×100). GPR137, G protein-coupled receptor 137; GFP, green fluorescent protein; Con, control; Lv-shCon, control lentivirus; Lv-shGPR137, GPR137 short hairpin RNA-expressing lentivirus.