Helicobacter pylori disrupts gastric mucosal homeostasis by stimulating macrophages to secrete CCL3.

BACKGROUND: Helicobacter pylori (H. pylori) is the predominant etiological agent of gastritis and disrupts the integrity of the gastric mucosal barrier through various pathogenic mechanisms. After H. pylori invades the gastric mucosa, it interacts with immune cells in the lamina propria. Macrophages are central players in the inflammatory response, and H. pylori stimulates them to secrete a variety of inflammatory factors, leading to the chronic damage of the gastric mucosa. Therefore, the study aims to explore the mechanism of gastric mucosal injury caused by inflammatory factors secreted by macrophages, which may provide a new mechanism for the development of H. pylori-related gastritis. METHODS: The expression and secretion of CCL3 from H. pylori infected macrophages were detected by RT-qPCR, Western blot and ELISA. The effect of H. pylori-infected macrophage culture medium and CCL3 on gastric epithelial cells tight junctions were analyzed by Western blot, immunofluorescence and transepithelial electrical resistance. EdU and apoptotic flow cytometry assays were used to detect cell proliferation and apoptosis levels. Dual-luciferase reporter assays and chromatin immunoprecipitation assays were used to study CCL3 transcription factors. Finally, gastric mucosal tissue inflammation and CCL3 expression were analyzed by hematoxylin and eosin staining and immunohistochemistry. RESULTS: After H. pylori infection, CCL3 expressed and secreted from macrophages were increased. H. pylori-infected macrophage culture medium and CCL3 disrupted gastric epithelial cells tight junctions, while CCL3 neutralizing antibody and receptor inhibitor of CCL3 improved the disruption of tight junctions between cells. In addition, H. pylori-infected macrophage culture medium and CCL3 recombinant proteins stimulated P38 phosphorylation, and P38 phosphorylation inhibitor improved the disruption of tight junctions between cells. Besides, it was identified that STAT1 was a transcription factor of CCL3 and H. pylori stimulated macrophage to secret CCL3 through the JAK1-STAT1 pathway. Finally, after mice were injected with murine CCL3 recombinant protein, the gastric mucosal injury and inflammation were aggravated, and the phosphorylation level of P38 was increased. CONCLUSIONS: In summary, our findings demonstrate that H. pylori infection stimulates macrophages to secrete CCL3 via the JAK1-STAT1 pathway. Subsequently, CCL3 damages gastric epithelial tight junctions through the phosphorylation of P38. This may be a novel mechanism of gastric mucosal injury in H. pylori-associated gastritis.

Modulation of gut microbiota protects against viral respiratory tract infections: a systematic review of animal and clinical studies.

BACKGROUND: Earlier studies suggest that probiotics have protective effects in the prevention of respiratory tract infections (RTIs). Whether such benefits apply to RTIs of viral origin and mechanisms supporting the effect remain unclear. AIM: To determine the role of gut microbiota modulation on clinical and laboratory outcomes of viral RTIs. METHODS: We conducted a systematic review of articles published in Embase and MEDLINE through 20 April 2020 to identify studies reporting the effect of gut microbiota modulation on viral RTIs in clinical studies and animal models. The incidence of viral RTIs, clinical manifestations, viral load and immunological outcomes was evaluated. RESULTS: We included 58 studies (9 randomized controlled trials; 49 animal studies). Six of eight clinical trials consisting of 726 patients showed that probiotics administration was associated with a reduced risk of viral RTIs. Most commonly used probiotics were Lactobacillus followed by Bifidobacterium and Lactococcus. In animal models, treatment with probiotics before viral challenge had beneficial effects against influenza virus infection by improving infection-induced survival (20/22 studies), mitigating symptoms (21/21 studies) and decreasing viral load (23/25 studies). Probiotics and commensal gut microbiota exerted their beneficial effects through strengthening host immunity. CONCLUSION: Modulation of gut microbiota represents a promising approach against viral RTIs via host innate and adaptive immunity regulation. Further research should focus on next generation probiotics specific to viral types in prevention and treatment of emerging viral RTIs.

EGF Suppresses the Initiation and Drives the Reversion of TGF-ß1-induced Transition in Hepatic Oval Cells Showing the Plasticity of Progenitor Cells.

Transforming growth factor-ß1 (TGF-ß1) induces hepatic progenitors to tumor initiating cells through epithelial-mesenchymal transition (EMT), thus raising an important drawback for stem cell-based therapy. How to block and reverse TGF-ß1-induced transition is crucial for progenitors' clinical application and carcinogenic prevention. Rat adult hepatic progenitors, hepatic oval cells, experienced E-cadherin to N-cadherin switch and changed to α-smooth muscle actin (α-SMA) positive cells after TGF-ß1 incubation, indicating EMT. When TGF-ß1 plus EGF were co-administrated to these cells, EGF dose-dependently suppressed the cadherin switch and α-SMA expression. Interestingly, if EGF was applied to TGF-ß1-pretreated cells, the cells that have experienced EMT could return to their epithelial phenotype. Abruption of EGF receptor revealed that EGF exerted its blockage and reversal effects through phosphorylation of ERK1/2 and Akt. These findings suggest an important attribute of EGF on opposing and reversing TGF-ß1 effects, indicating the plasticity of hepatic progenitors.

PTOV1 facilitates colorectal cancer cell proliferation through activating AKT1 signaling pathway.

Background: Colorectal cancer is a predominant contributor to global cancer-related morbidity and mortality. The oncogene PTOV1 has been linked to various human malignancies, yet its specific role in CRC pathogenesis requires further elucidation. Methods: Our study used a comprehensive array of authoritative bioinformatics tools, such as TIMER, UCSC Xena, GEO, Human Protein Atlas, UALCAN, CIBERSORTx and others which used to investigate the complex effects of PTOV1 on gene expression profiles, diagnostic and prognostic biomarkers, tumor immunology, signaling pathways, epigenetic alterations, and genetic mutations. Gene expression validation was conducted using Western blot and qRT-PCR. The in vitro proliferative and migratory potentials of CRC cells were evaluated using CCK-8 assays, colony formation, and transwell migration assays, respectively. MSP was applied to assess the methylation status of the PTOV1 promoter region. Results: Our results reveal a significant association between increased PTOV1 expression, driven by promoter hypomethylation, and poor patient prognosis in CRC. Elevated PTOV1 levels were positively correlated with the enrichment of diverse immune cell subsets and immune-related molecules within the tumor microenvironment. In vitro assays demonstrated that PTOV1 knockdown markedly reduced CRC cell proliferation, colony formation, and migration, while ectopic PTOV1 expression had the opposite effect. Importantly, PTOV1 was shown to regulate the PI3K-AKT signaling pathway, significantly influencing the phosphorylation of AKT1 and the expression of cell cycle regulators P21 and P27. The pharmacological inhibition of AKT1 phosphorylation using MK2206 effectively counteracted the proliferative effects induced by PTOV1 overexpression. Conclusion: The ability of PTOV1 to enhance CRC cell proliferation via modulation of the AKT1 signaling pathway establishes it as a potential therapeutic target and a promising biomarker for prognostic stratification in CRC.

SULF1 inhibits proliferation and invasion of esophageal squamous cell carcinoma cells by decreasing heparin-binding growth factor signaling.

BACKGROUND: Heparin-binding growth factor signaling is involved in the pathogenesis and development of human cancers. It can be regulated by sulfation of cell-surface heparan sulfate proteoglycans (HSPG). SULF1 is a heparin-degrading endosulfatase which can modulate the sulfation of HSPGs. AIM: The purpose of this study was to elucidate the role of SULF1 in modulating proliferation and invasion of esophageal squamous cell carcinoma (ESCC) by decreasing heparin-binding growth factor signaling. METHODS: We restored SULF1 expression in the ESCC cell line KYSE150, and examined the effects of SULF1 expression on the proliferation and invasion of KYSE150 cells. In addition, we investigated the expression of SULF1 in human ESCC tissues and analyzed the correlation of SULF1 expression with clinicopathologic characteristics of ESCC. RESULTS: Our study shows that re-expression of SULF1 in ESCC cell line results in the downregulation of hepatocyte growth factor-mediated activation of MAPK pathways with a resultant decrease in cell invasiveness. Cell proliferation was also inhibited in SULF1-transfected KYSE150 cells. Immunohistochemical assays reveal that SULF1 is expressed in nearly half of the human ESCC tissues but not in normal esophageal epithelial cells. SULF1 expression in human ESCC tissues is negatively correlated with tumor size and tumor invasion. CONCLUSION: This study identified that SULF1 inhibits proliferation and invasion of ESCC by decreasing heparin-binding growth factor signaling and suggested that SULF1 plays an inhibiting role in the pathogenesis of ESCC.

ID1 expressing macrophages support cancer cell stemness and limit CD8+ T cell infiltration in colorectal cancer.

Elimination of cancer stem cells (CSCs) and reinvigoration of antitumor immunity remain unmet challenges for cancer therapy. Tumor-associated macrophages (TAMs) constitute the prominant population of immune cells in tumor tissues, contributing to the formation of CSC niches and a suppressive immune microenvironment. Here, we report that high expression of inhibitor of differentiation 1 (ID1) in TAMs correlates with poor outcome in patients with colorectal cancer (CRC). ID1 expressing macrophages maintain cancer stemness and impede CD8+ T cell infiltration. Mechanistically, ID1 interacts with STAT1 to induce its cytoplasmic distribution and inhibits STAT1-mediated SerpinB2 and CCL4 transcription, two secretory factors responsible for cancer stemness inhibition and CD8+ T cell recruitment. Reducing ID1 expression ameliorates CRC progression and enhances tumor sensitivity to immunotherapy and chemotherapy. Collectively, our study highlights the pivotal role of ID1 in controlling the protumor phenotype of TAMs and paves the way for therapeutic targeting of ID1 in CRC.

Expression and Significance of N-myc downstream regulated gene 2 in the process of Esophageal Squamous Cell Carcinogenesis.

It has been reported that the expression of tumor suppressor gene N-myc downstream-regulated gene 2 (NDRG2) was significantly reduced in human solid tumors, including esophageal squamous cell carcinoma (ESCC). This study aimed to explore whether the difference of NDRG2 expression exists in different stages of ESCC and provides a basis for the early diagnosis and prognosis of ESCC. Immunohistochemical staining was used to investigate the expression level of NDRG2 in samples from 91 patients with mild-to-moderate dysplasia, early ESCC, and advanced ESCC. The relationship between the expression of NDRG2 and clinicopathological characteristics of the patients was analyzed. The results showed that positive expression rates of NDRG2 in tissues adjacent to early ESCC (76.7%), or from mild-to-moderate dysplasia (74.1%), and early ESCC (83.3%) were significantly higher than in tissue from advanced ESCC (55.9%). The positive expression rate in advanced ESCC was significantly lower than in the other three tissue types (p < 0.05). There was a significant difference (p < 0.05) and correlation (Cramer's V = 0.351, p = 0.019, <0.05) between the expression of NDRG2 and the clinical stage in the 64 patients with ESCC. In conclusion, this study found that the expression of NDRG2 gradually decreased with the progression of esophageal lesions into advanced ESCC. This difference in positive expression rate was more obvious in male patients and patients under 60 years of age. Therefore, the detection of NDRG2 plays an important role in differentiating early ESCC from advanced ESCC.

TRIB3 reduces CD8+ T cell infiltration and induces immune evasion by repressing the STAT1-CXCL10 axis in colorectal cancer.

High CD8+ T cell infiltration in colorectal cancer (CRC) should suggest a favorable prognosis and a satisfactory response to immunotherapy; however, the vast majority of patients with CRC do not benefit from immunotherapy due to poor T cell infiltration. Therefore, a better understanding of the mechanisms for T cell exclusion from CRC tumors is needed. Tribbles homolog 3 (TRIB3) has been implicated as an oncoprotein, but its role in regulating antitumor immune responses has not been defined. Here, we demonstrated that TRIB3 inhibits CD8+ T cell infiltration in various CRC mouse models. We showed that TRIB3 was acetylated by acetyltransferase P300, which inhibited ubiquitination and subsequent proteasomal degradation of TRIB3. Ectopically expressed TRIB3 inhibited signal transducer and activator of transcription 1 (STAT1) activation and STAT1-mediated CXCL10 transcription by enhancing the epidermal growth factor receptor signaling pathway, causing a reduction in tumor-infiltrating T cells. Genetic ablation of Trib3 or pharmacological acceleration of TRIB3 degradation with a P300 inhibitor increased T cell recruitment and sensitized CRCs to immune checkpoint blockade therapy. These findings identified TRIB3 as a negative modulator of CD8+ T cell infiltration in CRCs, highlighting a potential therapeutic target for treating immunologically "cold" CRCs.

Epigenetic inactivation of the SFRP1 gene in esophageal squamous cell carcinoma.

INTRODUCTION: The secreted frizzled-related protein 1 (SFRP1) gene, as a Wnt signaling modulator, is frequently inactivated by promoter methylation in many tumors including gastric cancer, breast cancer, oral squamous cell carcinoma, and esophageal adenocarcinoma. However, the role of SFRP1 in esophageal squamous cell carcinoma (ESCC) is not clear. In this study, we investigated the epigenetic inactivation of the SFRP1 gene in ESCC. METHODS: Nine ESCC cell lines, two immortalized human esophageal epithelial cell lines, twenty ESCC tissues, and paired adjacent nontumor tissues were analyzed in the study. Methylation-specific polymerase chain reaction (PCR), bisulfite sequencing, reverse-transcription PCR, immunohistochemistry, and chromatin immunoprecipitation assay were used to detect SFRP1 promoter methylation, expression of the SFRP1 gene, and histone modification in the SFRP1 promoter region. RESULTS: The SFRP1 promoter was found to be highly methylated in 95% (19/20) of the ESCC tissues and in nine ESCC cell lines, compared with 65% (13/20) of the paired nontumor tissues. Moreover, we confirmed that complete methylation of the SFRP1 gene promoter was correlated with its greatly reduced expression level. After individual treatment with 5-aza-2'-deoxycytidine (DAC) and trichostatin A (TSA), the messenger RNA (mRNA) level of the SFRP1 gene was not obviously rescued in the EC9706 cell line. Combined incubation with DAC and TSA can, however, substantially increase the SFRP1 mRNA expression level in the EC9706 cell line. Chromatin immunoprecipitation assay showed that acetylated histone H3 and H4 were found in the SFRP1 promoter region. CONCLUSION: Promoter hypermethylation of SFRP1 is a frequent event in ESCC. Promoter methylation and histone acetylation may cooperatively regulate expression of the SFRP1 gene.

Effects of DNA methyltransferase 1 inhibition on esophageal squamous cell carcinoma.

To explore the role of DNA methyltransferase 1 (DNMT1) in esophageal squamous cell carcinoma (ESCC) and the potential of DNMT1-targeted small interfering RNA as ESCC therapy, we examined expression changes of DNMT1 in ESCC and investigated the effect of DNMT1 knockdown by RNA interference in a human ESCC cell line, KYSE30. DNMT1 messenger RNA was over-expressed in seven out of 12 ESCC samples, and the percentage of cells expressing DNMT1 was significantly higher in ESCC tissues compared with paired non-cancerous tissues. DNMT1 protein levels correlated with lymph node metastasis, but exhibited no correlation with sex, age, tumor site, or tumor differentiation. Knockdown of DNMT1 in KYSE30 cells using RNA interference resulted in a reduction of promoter methylation and re-expression of methyl-guanine methyl-transferase and retinoic acid receptors beta, inhibition of cell proliferation/viability and induction of cell apoptosis. These results indicate that DNMT1 over-expression is involved in ESCC and correlated with lymph node metastasis. Knockdown of DNMT1 led to promoter demethylation and re-expression of several tumor suppressor genes thereby inhibiting cell proliferation/viability and inducing cell apoptosis.