Effects of theHelicobacter pyloriVirulence Factor CagA and Ammonium Ion on Mucins in AGS Cells

Abstract

PurposeTo investigate the effects of Helicobacter pylori (H. pylori)-CagA and the urease metabolite on mucin expression in AGS cells.Materials and MethodsAGS cells were transfected with CagA and/or treated with different concentrations of NH4CL. Mucin gene and protein expression was assessed by qPCR and immunofluorescence assays, respectively.ResultsCagA significantly upregulated MUC5AC, MUC2, and MUC5B expression in AGS cells, but did not affect E-cadherin and MUC6 expression. MUC5AC, MUC6, and MUC2 expression in AGS cells increased with increasing concentrations until reaching a peak level at 15 mM. MUC5B mRNA expression in AGS cells ( concentration of 15 mM) was significantly higher than that at 0, 5, and 10 mM . No changes in E-cadherin expression in AGS cells treated with were noted, except at 20 mM. The expression of MUC5AC, MUC2, and MUC6 mRNA in CagA-transfected AGS cells at an concentration of 15 mM was significantly higher than that at 0 mM, and decreased at higher concentrations. The expression of MUC5B mRNA increased with increases in concentration, and was significantly higher compared to that in untreated cells. No significant change in the expression of E-cadherin mRNA in CagA-transfected AGS cells was observed. Immunofluorescence assays confirmed the observed changes.ConclusionH. pylori may affect the expression of MUC5AC, MUC2, MUC5B, and MUC6 in AGS cells via CagA and/or , but not E-cadherin.

The Hippo Kinase LATS2 Controls Helicobacter pylori-Induced Epithelial-Mesenchymal Transition and Intestinal Metaplasia in Gastric Mucosa

“…However, CDX2 upregulation could not be confirmed in siLATS2 MKN74 cells ( Figure 7E). MUC2 immunofluorescent staining was heterogeneous and mostly nuclear in noninfected siControl cells, as previously reported in AGS cells, 30 and its overexpression in siLATS2 cells in basal and infection conditions paralleled those of CDX2 both at the protein and the mRNA level in AGS cells (Figure 7A and D). IAP enzymatic activity appeared as cytoplasmic blue foci in AGS cells; the percentage of cells showing IAP foci was increased upon infection and particularly in siLATS2 infected cells, along with larger and more intense foci ( Figure 7B and C).…”

Cytotoxin-associated gene A increases carcinogenicity of helicobacter pylori in colorectal adenoma

“…20,[27][28][29] For the purpose of analyzing the effect of CagA on Hp-induced gastrin expression and CRA progression, we subsequently compared the serum gastrin expression and inter-tumor ki-67 expression between Hp + CagA + patients and Hp + CagA − patients, which elucidated that both of them were elevated in Hp + CagA + patients compared with Hp + CagA − patients, indicating that CagA enhanced the carcinogenic effect of Hp in CRA patients. There are several possible reasons for the result: (a) CagA was able to strengthen the virulence of Hp, thereby enhancing the gastrin upregulation as well as the ki-67 upregulation effect of Hp indirectly; 30,31 and (b) CagA might also directly promote gastrin expression, thereby increasing ki-67 expression. 23 Briefly, this large-sample-size study not only illuminated the positive correlation of Hp infection with higher CRA risk and worse disease conditions, but also disclosed the associations of Hp + CagA + with gastrin and ki-67 expressions in CRA patients.…”

The Diverse Roles of the Mucin Gene Cluster Located on Chromosome 11p15.5 in Colorectal Cancer

“… Van Seuningen et al (2000) investigated the 5′-flanking region and promoter activity of MUC5B in colon cancer cell lines and showed a cell-specific manner of MUC5B promoter activities, as MUC5B it is very active in mucus-secreting LS174T cells, whereas it is inactive in Cac-2 enterocytes and HT-29 undifferentiated cells. MUC5B upregulation has been found in human diseases, such as sinus mucosa polyps ( Wu et al, 2011 ), nasal polyps ( Amini et al, 2019 ), chronic obstructive pulmonary disease ( Hancock et al, 2018 ), and Helicobacter pylori-related gastropathy ( Zhang et al, 2018 ), suggesting the important role of MUC5B and its involvement in the pathogenesis of these diseases. In gastric and intestinal cancer cell lines, the expression of MUC5B was also found to be increased, such as HT-29 MTX cells ( Lesuffleur et al, 1995 ) and LS174T cells ( van Klinken et al, 1998 ).…”