Down-regulation of Bcl-2 is mediated by NF-κB activation in Helicobacter pylori-induced apoptosis of gastric epithelial cells

Hypoxia exacerbates the malignant transformation of gastric epithelial cells induced by long-term H. pylori infection

Helicobacter pylori is a microaerophilic Gram-negative bacterium that resides in the human stomach and is classified as a class I carcinogen for gastric cancer. Numerous studies have demonstrated that H. pylori infection plays a role in regulating the function of host cells, thereby contributing to the malignant transformation of these cells. However, H. pylori infection is a chronic process, and short-term cellular experiments may not provide a comprehensive understanding of the in vivo situation, especially when considering the lower oxygen levels in the human stomach. In this study, we aimed to investigate the mechanisms underlying gastric cell dysfunction after prolonged exposure to H. pylori under hypoxic conditions. We conducted a co-culture experiment using the gastric cell line GES-1 and H. pylori for 30 generations under intermittent hypoxic conditions. By closely monitoring cell proliferation, migration, invasion, autophagy, and apoptosis, we revealed that sustained H. pylori stimulation under hypoxic conditions significantly influences the function of GES-1 cells. This stimulation induces epithelial-mesenchymal transition and contributes to the propensity for malignant transformation of gastric cells. To confirm the in vitro results, we conducted an experiment involving Mongolian gerbils infected with H. pylori for 85 weeks. All the results strongly suggest that the Nod1 receptor signaling pathway plays a crucial role in H. pylori-related apoptosis and autophagy. In summary, continuous stimulation by H. pylori affects the functioning of gastric cells through the Nod1 receptor signaling pathway, increasing the likelihood of cell carcinogenesis. The presence of hypoxic conditions further exacerbates this process.IMPORTANCEDeciphering the collaborative effects of Helicobacter pylori infection on gastric epithelial cell function is key to unraveling the development mechanisms of gastric cancer. Prior research has solely examined the outcomes of short-term H. pylori stimulation on gastric epithelial cells under aerobic conditions, neglecting the bacterium's nature as a microaerophilic organism that leads to cancer following prolonged stomach colonization. This study mimics a more genuine in vivo infection scenario by repeatedly exposing gastric epithelial cells to H. pylori under hypoxic conditions for up to 30 generations. The results show that chronic exposure to H. pylori in hypoxia substantially increases cell migration, invasion, and epithelial-mesenchymal transition, while suppressing autophagy and apoptosis. This highlights the significance of hypoxic conditions in intensifying the carcinogenic impact of H. pylori infection. By accurately replicating the in vivo gastric environment, this study enhances our comprehension of H. pylori's pathogenic mechanisms in gastric cancer.

Sustained Exposure to Helicobacter pylori Lysate Inhibits Apoptosis and Autophagy of Gastric Epithelial Cells

Helicobacter pylori is designated as a class I carcinogen of human gastric cancer following long-term infection. During this process, H. pylori bacteria persist in proliferation and death, and release bacterial components that come into contact with gastric epithelial cells and regulate host cell function. However, the impact of long-term exposure to H. pylori lysate on the pathological changes of gastric cells is not clear. In this study, we aimed to investigate the regulation and mechanisms involved in gastric cell dysfunction following continuous exposure to H. pylori lysate. We co-cultured gastric cell lines GES-1 and MKN-45 with H. pylori lysate for 30 generations, and we found that sustained exposure to H. pylori lysate inhibited GES-1 cell invasion, migration, autophagy, and apoptosis, while it did not inhibit MKN-45 cell invasion or migration. Furthermore, Mongolian gerbils infected with H. pylori ATCC 43504 strains for 90 weeks confirmed the in vitro results. The clinical and in vitro data indicated that sustained exposure to H. pylori lysate inhibited cell apoptosis and autophagy through the Nod1-NF-κB/MAPK-ERK/FOXO4 signaling pathway. In conclusion, sustained exposure to H. pylori lysate promoted proliferation of gastric epithelial cells and inhibited autophagy and apoptosis via Nod1-NF-κB/MAPK-ERK/FOXO4 signaling pathway. In the process of H. pylori-induced gastric lesions, H. pylori lysate plays as an “accomplice” to carcinogenesis.

Dangerous Liaison: Helicobacter pylori, Ganglionitis, and Myenteric Gastric Neurons: A Histopathological Study

Chronic inflammation induced by Helicobacter pylori (H. pylori) infection plays a major role in development of gastric cancer. However, recent findings suggested that progression of inflammation and neoplastic transformation in H. pylori infection are more complex than previously believed and could involve different factors that modulate gastric microenvironment and influence host-pathogen interaction. Among these factors, gastric myenteric plexus and its potential adaptive changes in H. pylori infection received little attention. This study is aimed at identifying the impact of H. pylori-associated gastritis on number and morphology of nerve cells in the stomach. The distribution of density, inflammation, and programmed cell death in neurons was immunohistochemically assessed in full-thickness archival tissue samples obtained from 40 patients with H. pylori infection who underwent surgery for gastric cancer and were compared with findings on samples collected from 40 age- and sex-matched subjects without bacteria. Overall, significant differences were noted between H. pylori-positive and H. pylori-negative patients. The analysis of tissue specimens obtained from those with infection revealed higher density and larger surface of the myenteric nervous plexus, as well as a significant increase in the number of gastric neuronal cell bodies and glial cells compared to controls. A predominant CD3-immunoreactive T cell infiltrate confined to the myenteric plexus was observed in infected subjects. The presence of mature B lymphocytes, plasma cells, and eosinophils was also noted, but to a lesser extent, within the ganglia. Myenteric ganglionitis was associated with degeneration and neuronal loss. Our results represent the first histopathological evidence supporting the hypothesis that H. pylori-induced gastric inflammation may induce morphological changes in myenteric gastric ganglia. These findings could help gain understanding of some still unclear aspects of pathogenesis of H. pylori infection, with the possibility of having broader implications for gastric cancer progression.

Involvement of mitochondrial apoptotic pathway and MAPKs/NF-κ B inflammatory pathway in the neuroprotective effect of atractylenolide III in corticosterone-induced PC12 cells

Atractylenolide III (ATL-III), a sesquiterpene compound isolated from Rhizoma Atractylodis Macrocephalae, has revealed a number of pharmacological properties including anti-inflammatory, anti-cancer activity, and neuroprotective effect. This study aimed to evaluate the cytoprotective efficiency and potential mechanisms of ATL-III on corticosterone injured rat phaeochromocytoma (PC12) cells. Our results demonstrate that ATL-III increases cell viability and reduces the release of lactate dehydrogenase (LDH). The results suggest that ATL-III protects PC12 cells from corticosterone-induced injury by inhibiting the intracellular Ca²⁺ overloading, inhibiting the mitochondrial apoptotic pathway and modulating the MAPK/NF-ΚB inflammatory pathways. These findings provide a novel insight into the molecular mechanism by which ATL-III protected the PC12 cells against corticosterone-induced injury for the first time. Our results provide the evidence that ATL-III may serve as a therapeutic agent in the treatment of depression.

Varroa destructor parasitism has a greater effect on proteome changes than the deformed wing virus and activates TGF-β signaling pathways

Honeybee workers undergo metamorphosis in capped cells for approximately 13 days before adult emergence. During the same period, Varroa mites prick the defenseless host many times. We sought to identify proteome differences between emerging Varroa-parasitized and parasite-free honeybees showing the presence or absence of clinical signs of deformed wing virus (DWV) in the capped cells. A label-free proteomic analysis utilizing nanoLC coupled with an Orbitrap Fusion Tribrid mass spectrometer provided a quantitative comparison of 2316 protein hits. Redundancy analysis (RDA) showed that the combination of Varroa parasitism and DWV clinical signs caused proteome changes that occurred in the same direction as those of Varroa alone and were approximately two-fold higher. Furthermore, proteome changes associated with DWV signs alone were positioned above Varroa in the RDA. Multiple markers indicate that Varroa activates TGF-β-induced pathways to suppress wound healing and the immune response and that the collective action of stressors intensifies these effects. Furthermore, we indicate JAK/STAT hyperactivation, p53-BCL-6 feedback loop disruption, Wnt pathway activation, Wnt/Hippo crosstalk disruption, and NF-κB and JAK/STAT signaling conflict in the Varroa–honeybee–DWV interaction. These results illustrate the higher effect of Varroa than of DWV at the time of emergence. Markers for future research are provided.

Combined inhibition of Bcl-2 and NFκB synergistically induces cell death in cutaneous T-cell lymphoma

Therapeutic options for cutaneous T-cell lymphoma (CTCL) are limited and curative treatment regimens are not available. Thus, new targeted and well-tolerated therapeutic approaches are urgently needed. In this respect, we have recently shown that dimethyl fumerate (DMF) inhibits NF-κB acting as a survival factor in CTCL. Similarly, inhibition of the antiapoptotic protein B-cell lymphoma 2 (Bcl-2) has been shown to induce cell death in CTCL especially when combined with histone deacetylase inhibitors. Therefore, we hypothesized that inhibition of Bcl-2 should potentiate NF-κB inhibition in a novel combination treatment of CTCL. We show that, in vitro, the Bcl-2 inhibitors ABT-199 and ABT-263 induced specific cell death in primary CD4⁺ cells from CTCL patients as well as in the CTCL cell line SeAx, but not in T cells of healthy donors nor in the CTCL cell line HH, which lacks Bcl-2. Combined treatment with ABT-199 and DMF caused synergistic cell death specifically in CTCL cells engaging 2 independent signaling pathways. To verify these findings in vivo, we performed combined ABT-199 and DMF treatment in a xenograft mouse model for CTCL. The combined treatment effectively reduced tumor growth and increased overall survival via synergistic induction of CTCL cell death and suppression of tumor cell proliferation. Essentially, the combination treatment was superior to ABT-199 monotherapy with respect to both efficacy and tolerability. To sum up, our data provide proof of principle for the therapeutic potential of combining Bcl-2 and NF-κB inhibitors in treating CTCL. Next, this potential should be explored further in a clinical study.

Resveratrol promotes the sensitivity of small-cell lung cancer H446 cells to cisplatin by regulating intrinsic apoptosis

The aim of the present study was to evaluate the effects of resveratrol on small-cell lung cancer (SCLC) cell proliferation and apoptosis. The results demonstrated that resveratrol concentration- and time-dependently reduced H446 cell viability. In addition, cells treated with resveratrol displayed higher apoptotic rates, in association with mitochondrial depolarization, cytochrome c release from the mitochondrial compartment to the cytoplasm, apoptosis-inducing factor translocation from the mitochondrial compartment to the nucleus, and altered protein levels of Bcl-2, Bcl-xL and Bax. Furthermore, resveratrol promoted H446 cell inhibition by cisplatin, as reflected by reduced viability and increased apoptosis. These findings suggest that resveratrol exerts antitumor effects on SCLC H446 cells and promotes H446 cell killing by cisplatin via modulation of intrinsic apoptosis.

Isoliquiritigenin suppresses IL-1β induced apoptosis and inflammation in chondrocyte-like ATDC5 cells by inhibiting NF-κB and exerts chondroprotective effects on a mouse model of anterior cruciate ligament transection

Isoliquiritigenin (ISL), a natural flavonoid extracted from licorice, has been demonstrated to exert attenuation of the nuclear factor-κB (NF-κB) signaling pathway and anti-inflammatory activity in a wide variety of cells. In the present study, the authors first evaluated the effects of ISL on cartilage degeneration in interleukin-1β (IL-1β)-stimulated chondrocyte-like ATDC5 cells and in a mouse model of osteoarthritis (OA). The data of a cell counting kit-8 and flow cytometry assay indicated that ISL suppressed the inhibitory effect of IL-1β on cell viability. The mRNA and protein expression levels of cyclooxygenase-2 and matrix metalloproteinase-13 were significantly decreased, while the expression of collagen II was increased, as indicated by RT-qPCR and western blot analysis following the chondrocyte-like ATDC5 cells were co-intervened with IL-1β and ISL for 48 h. Also, ISL attenuated protein expressions level of pro-apoptotic Bax, cleaved-caspase-3 and cleaved-caspase-9 and promoted expression of anti-apoptotic Bcl-2. Moreover, ISL inhibited NF-κB p65 phosphorylation induced by IL-1β. In addition, ISL also increased improved the thickness of hyaline cartilage and the production of proteoglycans in the cartilage matrix in a mouse OA model. These results indicated that ISL exerted anti-inflammatory and anti-apoptotic effects on IL-1β-stimulated chondrocyte-like ATDC5 cells, which may be associated with the downregulation of the NF-κB signaling pathway. In this way, the data supported the conclusion that ISL may be a novel potential preventive agent suitable for use in OA therapy.

Iso-suillin from Suillus flavus Induces Apoptosis in Human Small Cell Lung Cancer H446 Cell Line

Background:

The suillin isoform iso-suillin is a natural substance isolated from a petroleum ether extract of the fruiting bodies of the mushroom Suillus flavus. Previous studies have found its inhibition effect on some cancer cells, and we aimed to study its effects on human small cell lung cancer H446 cell line.

Methods:

Cell viability was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay. Cellular morphological changes (apoptosis and necrosis) were evaluated using an electron microscope and Hoechst 33258 staining detected by the inverted microscope. Flow cytometry was used to detect cell apoptosis, cell cycle distribution, and mitochondrial membrane potential. Protein expression was determined by Western blotting analysis.

Results:

Here, we describe the ability of iso-suillin to inhibit the growth of H446 cells in time- and dose-dependent way. Iso-suillin had no obvious impact on normal human lymphocyte proliferation at low concentrations (9.09, 18.17, or 36.35 μmol/L) but promoted lymphocyte proliferation at a high concentration (72.70 μmol/L). After treatment of different concentrations of iso-suillin (6.82, 13.63, or 20.45 μmol/L), the apoptosis rate of H446 cells increased with increasing concentrations of iso-suillin (16.70%, 35.54%, and 49.20%, respectively, all P < 0.05 compared with the control), and the expression of related apoptotic proteins in the mitochondrial pathway including cytochrome c and caspase-9 were up-regulated compared with the control (all P < 0.05). On the contrary, Bcl-2/Bax ratio was down-regulated compared with the control. Besides, the expression of pro-apoptotic proteins in the death receptor apoptosis pathway, including Fas-associating protein with a novel death domain and caspase-8, and the expression of caspase-3, a downstream regulatory protein of apoptosis, were also increased compared with the control (all P < 0.05). Inhibitors of caspase-9 and caspase-8 reversed the apoptosis process in H446 cells to varying degrees.

Conclusions:

These results suggest that iso-suillin could induce H446 cell apoptosis through the mitochondrial pathway and the death-receptor pathway. Therefore, iso-suillin might have a potential application as a novel drug for lung cancer treatment.

Baicalin attenuates lipopolysaccharide induced inflammation and apoptosis of cow mammary epithelial cells by regulating NF-κB and HSP72

Baicalin is the main ingredient of traditional Chinese herbal medicine, Scutellaria baicalensis, which has been widely used clinically as an anti-inflammatory agent. However, molecular mechanism of action of this drug is not yet clear. In the present study, the protective mechanism of baicalin against lipopolysaccharide (LPS) induced inflammatory injury in cow mammary epithelial cells (CMECs) was explored. For this purpose, in vitro cultured CMECs were treated with baicalin (10μg/mL) and LPS (10μg/mL) for 24 and 12h, respectively, and the cell viability was measured by using cell counting kit-8 (CCK-8). The results revealed that LPS induced inflammatory responses, as p-p65/p65 and p-IκBα/IκBα ratios and TNF-α and IL-1β production was increased in the CMECs. Both Bcl-2/Bax ratio and cell viability were decreased and caspase-3 cleaved following LPS treatment, indicating apoptosis of CMECs. Moreover, both LPS and baicalin increased HSP72 expression of the CMECs. However, cellular inflammatory responses and apoptosis were significantly reduced in baicalin treated CMECs. In conclusion, baicalin ameliorated inflammation and apoptosis of the CMECs induced by LPS via inhibiting NF-κB activation and up regulation of HSP72.

LIGHT/IFN-γ triggers β cells apoptosis via NF-κB/Bcl2-dependent mitochondrial pathway

LIGHT recruits and activates naive T cells in the islets at the onset of diabetes. IFN‐γ secreted by activated T lymphocytes is involved in beta cell apoptosis. However, whether LIGHT sensitizes IFNγ‐induced beta cells destruction remains unclear. In this study, we used the murine beta cell line MIN6 and primary islet cells as models for investigating the underlying cellular mechanisms involved in LIGHT/IFNγ – induced pancreatic beta cell destruction. LIGHT and IFN‐γ synergistically reduced MIN6 and primary islet cells viability; decreased cell viability was due to apoptosis, as demonstrated by a significant increase in Annexin V⁺ cell percentage, detected by flow cytometry. In addition to marked increases in cytochrome c release and NF‐κB activation, the combination of LIGHT and IFN‐γ caused an obvious decrease in expression of the anti‐apoptotic proteins Bcl‐2 and Bcl‐xL, but an increase in expression of the pro‐apoptotic proteins Bak and Bax in MIN6 cells. Accordingly, LIGHT deficiency led to a decrease in NF‐κB activation and Bak expression, and peri‐insulitis in non‐obese diabetes mice. Inhibition of NF‐κB activation with the specific NF‐κB inhibitor, PDTC (pyrrolidine dithiocarbamate), reversed Bcl‐xL down‐regulation and Bax up‐regulation, and led to a significant increase in LIGHT‐ and IFN‐γ‐treated cell viability. Moreover, cleaved caspase‐9, ‐3, and PARP (poly (ADP‐ribose) polymerase) were observed after LIGHT and IFN‐γ treatment. Pretreatment with caspase inhibitors remarkably attenuated LIGHT‐ and IFNγ‐induced cell apoptosis. Taken together, our results indicate that LIGHT signalling pathway combined with IFN‐γ induces beta cells apoptosis via an NF‐κB/Bcl2‐dependent mitochondrial pathway.

(-)-Epigallocatechin-3-gallate Modulates the Differential Expression of Survivin Splice Variants and Protects Spermatogenesis During Testicular Torsion

The anti-apoptotic effect of (-)-epigallocatechin-3-gallate (EGCG) during unilateral testicular torsion and detorsion (TT/D) was established in our previous study. In mice, the smallest inhibitor of apoptosis, survivin, is alternatively spliced into three variants, each suggested to have a unique function. Here, we assessed how EGCG exerts its protective effect through the expression of the different survivin splice variants and determined its effect on the morphology of the seminiferous tubules during TT/D. Three mouse groups were used: sham, TT/D+vehicle and TT/D treated with EGCG. The expression of the survivin variants (140 and 40) and other apoptosis genes (p53, Bax and Bcl-2) was measured with semi-quantitative RT-PCR. Histological analysis was performed to assess DNA fragmentation, damage to spermatogenesis and morphometric changes in the seminiferous tubules. In the TT/D+vehicle group, survivin 140 expression was markedly decreased, whereas survivin 40 expression was not significantly different. In parallel, there was an increase in the mRNA level of p53 and the Bax to Bcl-2 ratio in support of apoptosis induction. Histological analyses revealed increased DNA fragmentation and increased damage to spermatogenesis associated with decreased seminiferous tubular diameter and decreased germinal epithelial cell thickness in the TT/D+vehicle group. These changes were reversed to almost sham levels upon EGCG treatment. Our data indicate that EGCG protects the testis from TT/D-induced damage by protecting the morphology of the seminiferous tubules and modulating survivin 140 expression.

(-)-Epigallocatechin-3-gallate protects against NO-induced ototoxicity through the regulation of caspase- 1, caspase-3, and NF-κB activation

Excessive nitric oxide (NO) production is toxic to the cochlea and induces hearing loss. However, the mechanism through which NO induces ototoxicity has not been completely understood. The aim of this study was to gain further insight into the mechanism mediating NO-induced toxicity in auditory HEI-OC1 cells and in ex vivo analysis. We also elucidated whether and how epigallocatechin-3-gallate (EGCG), the main component of green tea polyphenols, regulates NO-induced auditory cell damage. To investigate NO-mediated ototoxicity, S-nitroso-N-acetylpenicillamine (SNAP) was used as an NO donor. SNAP was cytotoxic, generating reactive oxygen species, releasing cytochrome c, and activating caspase-3 in auditory cells. NO-induced ototoxicity also mediated the nuclear factor (NF)-κB/caspase-1 pathway. Furthermore, SNAP destroyed the orderly arrangement of the 3 outer rows of hair cells in the basal, middle, and apical turns of the organ of Corti from the cochlea of Sprague-Dawley rats at postnatal day 2. However, EGCG counteracted this ototoxicity by suppressing the activation of caspase-3/NF-κB and preventing the destruction of hair cell arrays in the organ of Corti. These findings may lead to the development of a model for pharmacological mechanism of EGCG and potential therapies against ototoxicity.

Diagnostic value of serum P35 in comparison with tissue P35 in gastric adenocarcinoma and their relationship with microscopic prognostic factors

Early diagnosis of Gastric adenocarcinoma could increase survival of the patients and also remarkably reduce treatment costs. This study aimed at evaluating the diagnostic value of serum P35 in comparison with tissue P35 in gastric adenocarcinoma and their relationship with microscopic prognostic factors. In this descriptive analytical study, 35 patients (74.3% male and 25.7% female with mean age of 63.00 +/- 12.75 years with gastric adenocarcinoma were evaluated. Blood samples were taken from all patients before gastrectomy to evaluate serum P35 with ELISA method and after surgery tissue samples were gathered to evaluate tissue P35 with immunohistochemical method. The relation between tissue and serum P35 with severity of the disease and microscopic findings was assessed. Tissue P35 was negative in 57.1%, positive in 22.9% and very positive in 20%. Mean serum P35 was 1.34 +/- 0.43 mg dL(-1). There was no relation between serum P35 and adenocarcinoma type, tumor grade, vascular and neurological invasion and number of lymph node involved. Serum P35 levels significantly increased by increase in tissue P35 positivity (p = 0.004). There was significant correlation between tissue P35 and adenocarcinoma type (p = 0.006), neurological involvement (p = 0.04) and number of involved lymph nodes (p = 0.001). Although serum P35 level was higher in cases with more lymph node involvement and vascular and neural invasion, the marker was not capable to predict the involvement degree of stomach cancer. In comparison with serum P35, tissue P35 plays more significant role in these cases.

Gene expression profiling in gastric mucosa from Helicobacter pylori-infected and uninfected patients undergoing chronic superficial gastritis

Helicobacter pylori infection reprograms host gene expression and influences various cellular processes, which have been investigated by cDNA microarray using in vitro culture cells and in vivo gastric biopsies from patients of the Chronic Abdominal Complaint. To further explore the effects of H. pylori infection on host gene expression, we have collected the gastric antral mucosa samples from 6 untreated patients with gastroscopic and pathologic confirmation of chronic superficial gastritis. Among them three patients were infected by H. pylori and the other three patients were not. These samples were analyzed by a microarray chip which contains 14,112 cloned cDNAs, and microarray data were analyzed via BRB ArrayTools software and Ingenuity Pathways Analysis (IPA) website. The results showed 34 genes of 38 differentially expressed genes regulated by H. pylori infection had been annotated. The annotated genes were involved in protein metabolism, inflammatory and immunological reaction, signal transduction, gene transcription, trace element metabolism, and so on. The 82% of these genes (28/34) were categorized in three molecular interaction networks involved in gene expression, cancer progress, antigen presentation and inflammatory response. The expression data of the array hybridization was confirmed by quantitative real-time PCR assays. Taken together, these data indicated that H. pylori infection could alter cellular gene expression processes, escape host defense mechanism, increase inflammatory and immune responses, activate NF-κB and Wnt/β-catenin signaling pathway, disturb metal ion homeostasis, and induce carcinogenesis. All of these might help to explain H. pylori pathogenic mechanism and the gastroduodenal pathogenesis induced by H. pylori infection.

Lycopene inhibits Helicobacter pylori-induced ATM/ATR-dependent DNA damage response in gastric epithelial AGS cells

Oxidative stress linked to DNA damage is involved in the pathogenesis of Helicobacter pylori-associated gastric diseases. The DNA damage response (DDR) coordinates cell-cycle transitions, DNA repair, and apoptosis through the activation of ataxia-telangiectasia-mutated (ATM) and ATM and Rad3-related (ATR) and their target proteins. However, neither H. pylori-induced DDR nor the effects of antioxidants on the DNA damage have been established. This study aimed to investigate the detailed process of H. pylori-induced DNA damage and to examine whether lycopene, a natural antioxidant, inhibits DNA damage and cellular response of gastric epithelial AGS cells infected with H. pylori. AGS cells were cultured with H. pylori in Korean isolates and treated with or without lycopene. Cell viability, DNA damage indices, levels of 8-OH-dG, and reactive oxygen species (ROS) as well as cell-cycle distributions were determined. The activation of ATM, ATR, Chk1, and Chk2; histone H2AX focus formation; activation and induction of p53; and levels of Bax and Bcl-2 and poly(ADP-ribose) polymerase-1 (PARP-1) were assessed. The results showed that H. pylori induced apoptosis in AGS cells with increased Bax and decreased Bcl-2 expression as well as PARP-1 cleavage. Culture with H. pylori led to increases in intracellular ROS, 8-OH-dG, double-strand DNA breaks (DSBs), and DNA fragmentation. H. pylori induced activation of the ATM/Chk2 and ATR/Chk1 pathways, phosphorylation of H2AX and p53, and a delay in the progression of the cells entering the S phase. Lycopene inhibited H. pylori-induced increases in ROS, apoptosis, alterations in cell-cycle distribution, DSBs, and ATM- and ATR-mediated DDR in AGS cells. In conclusion, lycopene may be beneficial for treatment of H. pylori-induced gastric diseases associated with oxidative DNA damage.

Interleukin-8 is the single most up-regulated gene in whole genome profiling of H. pylori exposed gastric epithelial cells

BACKGROUND

The association between Helicobacter pylori infection and upper gastrointestinal disease is well established. However, only a small fraction of H. pylori carriers develop disease, and there are great geographical differences in disease penetrance. The explanation to this enigma lies in the interaction between the bacterium and the host. H. pylori Outer Membrane Phospholipase A (OMPLA) has been suggested to play a role in the virulence of this bacterium. The aim of this study was to profile the most significant cellular pathways and biological processes affected in gastric epithelial cells during 24 h of H. pylori exposure, and to study the inflammatory response to OMPLA⁺ and OMPLA⁻ H. pylori variants.

RESULTS

Interleukin-8 was the most significantly up-regulated gene and appears to play a paramount role in the epithelial cell response to H. pylori infection and in the pathological processes leading to gastric disease. MAPK and NF-kappaB cellular pathways were powerfully activated, but did not seem to explain the impressive IL-8 response. There was marked up-regulation of TP53BP2, whose corresponding protein ASPP2 may interact with H. pylori CagA and cause marked p53 suppression of apoptosis. Other regulators of apoptosis also showed abberant regulation. We also identified up-regulation of several oncogenes and down-regulation of tumor suppressor genes as early as during the first 24 h of infection. H. pylori OMPLA phase variation did not seem to influence the inflammatory epithelial cell gene response in this experiment.

CONCLUSION

In whole genome analysis of the epithelial response to H. pylori exposure, IL-8 demonstrated the most marked up-regulation, and was involved in many of the most important cellular response processes to the infection. There was dysregulation of apoptosis, tumor suppressor genes and oncogenes as early as in the first 24 h of H. pylori infection, which may represent early signs of gastric tumorigenesis. OMPLA⁺/⁻ did not affect the acute inflammatory response to H. pylori.