Helicobacter pylori upregulates Nanog and Oct4 via Wnt/β-catenin signaling pathway to promote cancer stem cell-like properties in human gastric cancer

Abstract

Helicobacter pylori (H. pylori) infection is considered a major risk factor for gastric cancer. CagA behaves as a major bacterial oncoprotein playing a key role in H. pylori-induced tumorigenesis. Cancer stem cells (CSCs) are believed to possess the ability to initiate tumorigenesis and promote progression. Although studies have suggested that cancer cells can exhibit CSC-like properties in the tumor microenvironment, it remains unclear whether H. pylori infection could induce the emergence of CSC-like properties in gastric cancer cells and, the underlying mechanism. Here, gastric cancer cells were co-cultured with a CagA-positive H. pylori strain or a CagA isogenic mutant strain. We found that H. pylori-infected gastric cancer cells exhibited CSC-like properties, including an increased expression of CSC specific surface markers CD44 and Lgr5, as well as that of Nanog, Oct4 and c-myc, which are known pluripotency genes, and an increased capacity for self-renewal, whereas these properties were not observed in the CagA isogenic mutant strain-infected cells. Further studies revealed that H. pylori activated Wnt/β-catenin signaling pathway in a CagA-dependent manner and that the activation of this pathway was dependent upon CagA-positive H. pylori-mediated phosphorylation of β-catenin at the C-terminal Ser675 and Ser552 residues in a c-met- and/or Akt-dependent manner. We further demonstrated that this activation was responsible for H. pylori-induced CSC-like properties. Moreover, we found the promoter activity of Nanog and Oct4 were upregulated, and β-catenin was observed to bind to these promoters during H. pylori infection, while a Wnt/β-catenin inhibitor suppressed promoter activity and binding. Taken together, these results suggest that H. pylori upregulates Nanog and Oct4 via Wnt/β-catenin signaling pathway to promote CSC-like properties in gastric cancer cells.

Gene expression and pathway analysis of CTNNB1 in cancer and stem cells

“…KRAS-mutation-specific T cells, as well as personalized mutation-specific T cells, have been identified, and these may be useful in the future for individual cancer immunotherapeutics[47]. It has been reported that Helicobacter pylori up-regulates Nanog and Oct4 expression via Wnt/β-catenin signaling[48]. Wnt/β-catenin signaling and the phosphorylation of β-catenin may be involved in stemness in gastric cancer[48].…”

“…It has been reported that Helicobacter pylori up-regulates Nanog and Oct4 expression via Wnt/β-catenin signaling[48]. Wnt/β-catenin signaling and the phosphorylation of β-catenin may be involved in stemness in gastric cancer[48]. …”

Type IV Secretion and Signal Transduction of Helicobacter pylori CagA through Interactions with Host Cell Receptors

“…It appears that the CagA/E-cadherin complex impairs the interaction between E-cadherin and pro-oncogenic β-catenin, resulting in the cytoplasmic and nuclear accumulation of β-catenin (Figure 1E). Nuclear accumulation of β-catenin is also increased in biopsies from patients with early and late gastric carcinoma [110,111] and in the gastric epithelium of Mongolian gerbils infected with the highly cancerogenic H. pylori strain 7.13 [112]. In MKN28 and MKN45 human gastric epithelial cells, transfected CagA deregulated β-catenin and then transactivated T-cell factor/lymphoid enhancer factor (TCF/LEF) and CDX1 transcription factor to induce the expression of cancer-associated Wnt target genes, such as c-myc and cyclin d1 [108].…”

Aberrant regulation of Wnt signaling in hepatocellular carcinoma

“…Aberrant activation of Wnt signaling may contribute to numerous malignancies, such as colon cancer[6,7], gastric cancer[8], esophageal cancer[9], HCC[10], and others. Approximately 95% of observed HCC cases showed deregulation of the Wnt signaling cascade[11].…”