In our present study, PPIase was identified as one of the 12 gastric cancer-specific H. pylori genes. The result was supported by PCR-based screening of H. pylori strains, demonstrating that 50% of the H. pylori isolates obtained from gastric ZVADFMK cancer patients were PPIase positive, whereas <24% of the H. pylori isolates from superficial gastritis patients were positive. PPIases catalyze the slow interconversion between cis and trans conformation of proline residues and affect protein folding and function (Kern et al., 1995). Thus, PPIases emerge as key
players in the control of fundamental proteins involved in cell proliferation and oncogenic transformation (Lu et al., 2007). Consistent with this, PPIases have been characterized as a virulence factor of L. pneumophila and T. cruzi (Fischer et al., 1992; Pereira et al., 2002). In addition, a novel pathogen-associated factor, HP0175, which contains PPIase core at its C-terminus, has been shown to induce gastric epithelial cell death through interaction with TLR4 (Pathak et al., 2006). Apoptosis contributes to the pathological outcome of the infection by disturbing the balance between the rate of new cell production and the rate of cell loss by apoptosis. Atrophic gastritis and gastric dysplasia after H. pylori
infection are associated with accelerated apoptosis of the gastric epithelium (Xia & Talley, 2001). PPIases may contribute to the pathology of gastric cancer by inducing hyperproliferation of gastric epithelium. Although PPIase is identified see more as a gastric cancer-specific H. pylori gene, our present result shows that fewer than a quarter of the superficial gastritis-associated H. pylori strains contain this gene. Given that PPIase plays an important role in cell growth, apoptosis and oncogenic transformation, we would predict that the PPIase-positive subpopulation of the superficial gastritis patients may
have the potential to develop severe gastric diseases such as atrophic gastritis, gastric dysplasia and gastric cancer. Thus, it would be worthwhile to clinically follow-up these superficial gastritis patients infected SB-3CT with PPIase-positive H. pylori. PPIase may represent a novel marker for gastric cancer and a potential therapeutic target. This work was supported by grants from the National Basic Research Development Program of China (973 Program Award No.2010CB529304), National Natural Science Foundation of China (Award No.3100074) and the Foundation of the Key Laboratory of Cancer Intervention in Liaoning Province (Award No. 2009S106). “
“The cold stress response of Pseudomonas putida KT2440 was investigated by genomewide deep cDNA sequencing and gel-free MS-based protein profiling. Transcriptome and proteome profiles were assessed at 30 °C and 2 h after a downshift from 30 to 10 °C.