Fig 2: PRDX2 is overexpressed in gastric cancer, predicting prognosis.(A) Western blot analysis of PRDX2 and β-actin in gastric cancer cell lines. (B) qRT-PCR analysis of PRDX2 mRNA expression level in 40 normal and 40 gastric cancer tissue samples. (C) Immunohistochemistry staining of PRDX2 on human adjacent non-cancerous gastric and gastric cancer tissues. Scale Bar: 50 μm. (D) Kaplan-Meier analysis of overall survival (OS) in gastric cancer patients based on PRDX2 expression level. (E) Kaplan-Meier analysis of progression-free survival (PFS) in gastric cancer patients based on PRDX2 expression level. ***, P < 0.001.

Fig 3: Knockdown of PRDX2 enhances H. pylori-induced ROS level.(A) Left panel: the level of reactive oxygen species (ROS) was detected using H2DCFDA in control or PRDX2 siRNA knockdown AGS cells with or without H. pylori (7.13 or J166) infection for 6 h. Right upper panel: Western blot confirmed the knockdown of PRDX2 was efficient in AGS cells. Right lower panel: quantification data for A. (B), similar experiment in SUN-1 cells as in A. *, P < 0.05, **, P < 0.01, ***, P < 0.001.

Fig 4: Knockdown of PRDX2 increases the expression of p-H2A.X with or without H. pylori infection.The immunofluorescence staining of p-H2A.X in control or PRDX2 siRNA knockdown AGS cells with or without H. pylori (7.13 or J166) infection for 6 h. Right upper panel: Western blot confirmed the knockdown of PRDX2 was efficient in AGS cells. Right lower panel: quantification data for A. (B), similar experiment in SUN-1 cells as in A. *, P < 0.05, **, P < 0.01, ***, P < 0.001. (C) Western blot analysis of CagA, PRDX2, p–NF–kB-p65, NF-kB-p65, p-H2A.X, H2A.X and β-actin in control or PRDX2 siRNA knockdown AGS cells with or without H. pylori (7.13 or J166) infection for 6 h. (D), similar result in SNU-1 cells as C. **, P < 0.01, ***, P < 0.001.

Fig 5: PRDX2 expression is induced by H. pylori infections in vitro and in vivo.(A) and (B) Western blot data of CagA, PRDX2, p–NF–kB-p65, NF-kB-p65, and β-actin in AGS and SNU-1 cells infected with 7.13 (100 MOI), J166 (100 MOI) or PBS (Control) for 3 h and 6 h. (C) and (D) qRT-PCR analysis of PRDX2 mRNA expression levels in AGS and SNU-1 cells infected with 7.13 (100 MOI), J166 (100 MOI) or PBS (Control) for 6h. (E) Western blot analysis of PRDX2, p–NF–kB-p65, NF-kB-p65 and β-actin in control or PMSS1 infected mice for 1–2 weeks. (F) qRT-PCR analysis of PRDX2 mRNA expression level in control or PMSS1 infected mice 1–2 weeks. Quantification of Western blot data was performed using Image Lab software from Bio-Rad. *, P < 0.05, **, P < 0.01.