Acute and chronic infection of H. pylori caused the difference in apoptosis of gastric epithelial cells

Survivin as a potential biomarker for early diagnosis of the progression of precancerous lesions to gastric cancer

BACKGROUND

Gastric cancer is a common cancer developed in a carcinogenesis process from precancerous lesions including chronic gastritis, intestinal metaplasia, and dysplasia. Survivin, an inhibitor-of-apoptosis protein, is associated with the initiation and progression of gastric cancer. The present study aimed to evaluate the immunohistochemical expression patterns of survivin and its relationship with early diagnosis of gastric cancer in Iranian patients.

METHODS

In this retrospective case-control study, immunoexpression of survivin was investigated on sections obtained from formalin-fixed paraffin-embedded tissue blocks of 38 chronic gastritis, 32 intestinal metaplasia, 20 dysplasia, 28 gastric adenocarcinoma, and 22 controls.

RESULTS

Survivin immunoexpression in chronic gastritis was higher than controls, but this difference was not statistically significant (P > 0.05). However, survivin immunoexpression had a steady significant increase from control and chronic gastritis to intestinal metaplasia to dysplasia to gastric adenocarcinoma (P < 0.05). Sensitivity, specificity, and area under the curve of survivin immunohistochemical test for the diagnosis of gastric cancer were 87.5%, 74.4%, and 0.85, respectively. Males had a significantly higher survivin expression than females (P < 0.001). Also, survivin expression was significantly higher in older patients than in younger ones (P < 0.001).

CONCLUSION

It seems that the steady increase in survivin expression from different precancerous lesions to gastric adenocarcinoma suggests that survivin can be used as a potential biomarker for the prevention and early diagnosis of gastric cancer.

FTO-mediated m6A modification promotes malignant transformation of gastric mucosal epithelial cells in chronic Cag A+ Helicobacter pylori infection

OBJECTIVES

Cag A+ Helicobacter pylori chronic infection cause malignant transformation of the human gastric mucosa. N6-methyladenosine (m6A) modifications are the most common and abundant mRNA modifications and one of the pathways affecting tumorigenicity and tumor progression. However, the role of m6A modification in the process of chronic H. pylori infection leading to malignant transformation of gastric mucosa is unclear.

METHODS

In this study, we used Cag A- and Cag A+H. pylori chronic infection to establish cellular models in GES-1 cells and analyzed the cellular morphology, proliferation, apoptosis, invasiveness and tumorigenicity of gastric mucosal epithelial cells. The m6A expression levels of GES-1 cells after chronic infection with Cag A- and Cag A+H. pylori were examined, and modifying effect of FTO (the fat mass and obesity-associated protein) on CD44 was verified by MeRIP-qPCR. Finally, the FTO expression changes and m6A expression levels were further validated in clinical gastric cancer tissues.

RESULTS

Chronic Cag A+H. pylori-infected GES-1 cells exhibit altered cell morphology, apoptosis inhibition, abnormal proliferation, enhanced migration, colony formation, and increased stem cell-like properties. Meanwhile, FTO and CD44 expression was enhanced, and FTO may induce malignant transformation of gastric mucosa by regulating CD44 mRNA m6A methylation modifications.

CONCLUSIONS

We verified the effect of chronic stimulation of Cag A+H. pylori on malignant transformation of gastric mucosal epithelium. revealing the possibility of FTO in promoting malignant transformation of gastric mucosa by modifying CD44 mRNA methylation, suggesting that FTO expression is a potential molecule for malignant transformation of gastric mucosal epithelial cells.

Helicobacter pylori regulates stomach diseases by activating cell pathways and DNA methylation of host cells

One of the most prevalent malignant tumors of the digestive tract is gastric cancer (GC). Age, high salt intake, Helicobacter pylori (H. pylori) infection, and a diet deficient in fruits and vegetables are risk factors for the illness. A significant risk factor for gastric cancer is infection with H. pylori. Infecting gastric epithelial cells with virulence agents secreted by H. pylori can cause methylation of tumor genes or carcinogenic signaling pathways to be activated. Regulate downstream genes' aberrant expression, albeit the precise mechanism by which this happens is unclear. Oncogene, oncosuppressor, and other gene modifications, as well as a number of different gene change types, are all directly associated to the carcinogenesis of gastric cancer. In this review, we describe comprehensive H. pylori and its virulence factors, as well as the activation of the NF-κB, MAPK, JAK/STAT signaling pathways, and DNA methylation following infection with host cells via virulence factors, resulting in abnormal gene expression. As a result, host-related proteins are regulated, and gastric cancer progression is influenced. This review provides insight into the H. pylori infection, summarizes a series of relevant papers, discusses the complex signaling pathways underlying molecular mechanisms, and proposes new approach to immunotherapy of this important disease.

CMTM3 protects the gastric epithelial cells from apoptosis and promotes IL-8 by stabilizing NEMO during Helicobacter pylori infection

BACKGROUND

CKLF-like MARVEL transmembrane domain containing 3 (CMTM3) plays an important role in cancer development. Although Helicobacter pylori (H. pylori) infection is a main cause of gastric cancer, the function of CMTM3 during H. pylori infection remains unclear. CMTM3 expression levels in tissues from H. pylori-infected patients and cells co-cultured with H. pylori were analyzed. qRT-PCR and ELISA were used to investigate the effects of CMTM3 on interleukin 8 (IL-8) expression. Annexin V/propidium iodide staining was performed to evaluate the function of CMTM3 in the apoptosis of gastric epithelial cells. Proteomic analysis was performed to explore the underlying mechanism of CMTM3 during H. pylori infection. The interaction between CMTM3 and NEMO was determined via co-immunoprecipitation, HA-ubiquitin pull-down assay, and immunofluorescence.

RESULTS

H. pylori induced a significant increase in CMTM3 expression. CMTM3 inhibited gastric mucosal epithelial cells from apoptosis and increased the expression level of IL-8 during H. pylori infection. KEGG pathway enrichment analysis revealed that differentially expressed proteins were involved in epithelial cell signaling in H. pylori infection. CMTM3 directly interacted with NEMO, which promoted protein stabilization by down-regulation of its ubiquitylation.

CONCLUSIONS

CMTM3 reduces apoptosis and promotes IL-8 expression in the gastric epithelial cells by stabilizing NEMO during H. pylori infection. These findings characterize a new role for CMTM3 in host-pathogen interactions and provide novel insight into the molecular regulation of NEMO.

The protective effects of Xuebijing injection on intestinal injuries of mice exposed to irradiation

BACKGROUND

Gastrointestinal (GI) injury is one of the most common side effects of radiotherapy. However, there is no ideal therapy method except for symptomatic treatment in the clinic. Xuebijing (XBJ) is a traditional Chinese medicine, used to treat sepsis by injection. In this study, the protective effects of XBJ on radiation-induced intestinal injury (RIII) and its mechanism were explored.

METHODS

The effect of XBJ on survival of irradiated C57BL/6 mice was monitored. Histological changes including the number of crypts and the length of villi were evaluated by H&E. The expression of Lgr5⁺ intestinal stem cells (ISCs), Ki67⁺ cells, villin and lysozymes were examined by immunohistochemistry. The expression of cytokines in the intestinal crypt was detected by RT-PCR. DNA damage and apoptosis rates in the small intestine were also evaluated by immunofluorescence.

RESULTS

In the present study, XBJ improved the survival rate of the mice after 8.0 and 9.0 Gy total body irradiation (TBI). XBJ attenuated structural damage of the small intestine, maintained regenerative ability and promoted proliferation and differentiation of crypt cells, decreased apoptosis rate and reduced DNA damage in the intestine. Elevation of IL-6 and TNF-α was limited, but IL-1, TNF-𝛽 and IL-10 levels were increased in XBJ-treated group after irradiation. The expression of Bax and p53 were decreased after XBJ treatment.

CONCLUSIONS

Taken together, XBJ provides a protective effect on RIII by inhibiting inflammation and blocking p53-related apoptosis pathway.

Helicobacter pylori-induced reactive oxygen species direct turnover of CSN-associated STAMBPL1 and augment apoptotic cell death

Deubiquitinylases (DUBs) are central regulators of the ubiquitin system involved in protein regulation and cell signalling and are important for a variety of physiological processes. Most DUBs are cysteine proteases, and few other proteases are metalloproteases of the JAB1/MPN +/MOV34 protease family (JAMM). STAM-binding protein like 1 (STAMBPL1), a member of the JAMM family, cleaves ubiquitin bonds and has a function in regulating cell survival, Tax-mediated nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and epithelial-mesenchymal transition. However, the molecular mechanism by which STAMBPL1 influences cell survival is not well defined, especially with regard to its deubiquitinylation function. Here, we show that reactive oxygen species (ROS) induced by chemotherapeutic agents or the human microbial pathogen Helicobacter pylori can induce cullin 1-RING ubiquitin ligase (CRL1) and 26S proteasome-dependent degradation STAMBPL1. Interestingly, STAMBPL1 has a direct interaction with the constitutive photomorphogenic 9 (COP9 or CSN) signalosome subunits CSN5 and CSN6. The interaction with the CSN is required for the stabilisation and function of the STAMBPL1 protein. In addition, STAMBPL1 deubiquitinylates the anti-apoptotic protein Survivin and thus ameliorates cell survival. In summary, our data reveal a previously unknown mechanism by which the deubiquitinylase STAMBPL1 and the E3 ligase CRL1 balance the level of Survivin degradation and thereby determine apoptotic cell death. In response to genotoxic stress, the degradation of STAMBPL1 augments apoptotic cell death. This new mechanism may be useful to develop therapeutic strategies targeting STAMBPL1 in tumours that have high STAMBPL1 and Survivin protein levels.