Different microRNA expression levels in gastric cancer depending on Helicobacter pylori infection

MicroRNA-99 family in cancer: molecular mechanisms for clinical applications

MicroRNAs (miRNAs) are a class of non-coding RNA sequences that regulate gene expression post-transcriptionally. The miR-99 family, which is highly evolutionarily conserved, comprises three homologs: miR-99a, miR-99b, and miR-100. Its members are under-expressed in most cancerous tissues, suggesting their cancer-repressing properties in multiple cancers; however, in some contexts, they also promote malignant lesion progression. MiR-99 family members target numerous genes involved in various tumor-related processes such as tumorigenesis, proliferation, cell-cycle regulation, apoptosis, invasion, and metastasis. We review the recent research on this family, summarize its implications in cancer, and explore its potential as a biomarker and cancer therapeutic target. This review contributes to the clinical translation of the miR-99 family members.

Molecular Mechanisms and Treatment Strategies for Helicobacter pylori-Induced Gastric Carcinogenesis and Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma

Helicobacter pylori has been classified as a class I carcinogen by WHO because of its primary involvement in the development of gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. This review focuses on understanding the molecular pathophysiological mechanisms that operate within intracellular transduction pathways and their relevance in the treatment strategies for the two main diseases caused by H. pylori. H. pylori virulence factors such as cytotoxin-associated gene A and vacuolating cytotoxin A genotypes, inflammatory mediators, H. pylori-induced microRNA deregulation, alterations in autophagy proteins and regulators, and changes in DNA methylation are some of the molecular mechanisms that play essential roles in H. pylori infection and gastric carcinogenesis. The discovery of novel treatment strategies that target the deregulated intracellular transduction pathways in gastric carcinogenesis and MALT lymphoma is critical. H. pylori eradication (HPE) is not limited to H. pylori-dependent low-grade MALT lymphoma and may be used in patients with high-grade diffuse large B-cell lymphoma (DLBCL) (de novo or DLBCL-MALT lymphoma). The loss of H. pylori dependency and high-grade transformation appear to be distinct events in the progression of gastric lymphoma. Interestingly, patients with H. pylori-positive gastric DLBCL without histological evidence of MALT lymphoma (pure gastric DLBCL) may respond to HPE therapy.

Four differentially expressed exosomal miRNAs as prognostic biomarkers and therapy targets in endometrial cancer: Bioinformatic analysis

Endometrial cancer (EC) is one of the most common gynecological malignancies worldwide. Accumulated evidence has demonstrated exosomes of cancer cells carry microRNAs (miRNAs) to nonmalignant cells to induce metastasis. Our study aimed to find possible biomarkers of EC. Data for miRNA expression related with exosome from EC patients were downloaded from The Cancer Genome Atlas database, and the miRNA expression profiles associated with exosomes of EC were downloaded from the National Center for Biotechnology Information. We used different algorithms to analyze the differential miRNA expression, infer the relative proportion of immune infiltrating cells, predict chemotherapy sensitivity, and comprehensively score each gene set to evaluate the potential biological function changes of different samples. The gene ontology analysis and Kyoto encyclopedia of genome genomics pathway analysis were performed for specific genes. A total of 13 differential miRNAs were identified, of which 4 were up-regulated. The 4 miRNAs, that is hsa-miR-17-3p, hsa-miR-99b-3p, hsa-miR-193a-5p, and hsa-miR-320d, were the hub exosomal miRNAs that were all closely related to the clinic phenotypes and prognosis of patients. This study preliminarily indicates that the 4 hub exosomal miRNAs (hsa-miR-17-3p, hsa-miR-99b-3p, hsa-miR-193a-5p, and hsa-miR-320d) could be used as prognostic biomarkers or therapy targets in EC. Further studies are required to make sure of their real feasibility and values in the EC clinic and the relative research.

Effects of Helicobacter pylori Infection on the Development of Chronic Gastritis

BACKGROUND/AIMS

Based on the gene expression profiles of gastric epithelial tissue at different stages of Helicobacter pylori-infected gastritis, key long noncoding RNAs and genes in the development of Helicobacter pylori infection-induced gastritis were screened to provide a basis for early diagnosis and treatment.

MATERIALS AND METHODS

We downloaded 2 sets of sample data from the database, including gastric epithelial tissue samples from gastritis patients from Bhutan and Dominican, and screened mRNAs in the differentially expressed RNAs of the 2 regions. Mfuzz clustering algorithm was used to screen RNAs related to the 3 stages of chronic gastritis. The competing endogenous RNA (ceRNA) regulation network was constructed, and the selected key RNAs were verified. Samples from Bhutan and Dominican were subdivided into the chronic gastritis/ normal comparison groups, and the differentially expressed RNAs were screened to obtain 1067 overlapping RNAs, containing 21 long noncoding RNAs and 1046 mRNAs.

RESULTS

Thirty-eight significant gene ontology functional nodes and 6 expression pattern clusters were obtained. Two ceRNA regulatory networks were constructed, and 4 shared miRNAs (hsa-miR-320b, hsa-miR-320c, hsa-miR-320d, and hsa-miR-155-5p) were obtained. Eleven important long noncoding RNAs (AFAP1-AS1, MIR155HG, LINC00472, and FAM201A) and mRNAs (CASP10, SLC26A2, TRIB1, BMP2K, SCAMP1, TNKS1BP1, and MBOAT2) regulated by these 4 miRNAs were obtained. These results indicated that Helicobacter pylori infection had a certain influence on the development of gastritis.

CONCLUSIONS

The 11 key RNAs can provide a target for the early diagnosis and treatment of chronic gastritis following Helicobacter pylori infection.

Prognostic biomarkers and molecular pathways mediating Helicobacter pylori–induced gastric cancer: a network-biology approach

Cancer of the stomach is the second most frequent cancer-related death worldwide. The survival rate of patients with gastric cancer (GC) remains fragile. There is a requirement to discover biomarkers for prognosis approaches. Helicobacter pylori in the stomach is closely associated with the progression of GC. We identified the genes associated with poor/favorable prognosis in H. pylori–induced GC. Multivariate statistical analysis was applied on the Gene Expression Omnibus (GEO) dataset GSE54397 to identify differentially expressed miRNAs (DEMs) in gastric tissues with H. pylori–induced cancer compared with the H. pylori–positive with non-cancerous tissue. A protein interaction map (PIM) was built and subjected to DEMs targets. The enriched pathways and biological processes within the PIM were identified based on substantial clusters. Thereafter, the most critical genes in the PIM were illustrated, and their prognostic impact in GC was investigated. Considering p-value less than 0.01 and |Log2 fold change| as >1, five microRNAs demonstrated significant changes among the two groups. Gene functional analysis revealed that the ubiquitination system, neddylation pathway, and ciliary process are primarily involved in H. pylori–induced GC. Survival analysis illustrated that the overexpression of DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, and TXNIP was associated with poor prognosis, while increased MRPS5 expression was related to a favorable prognosis in GC patients. DOCK4, GNAS, CTGF, TGF-b1, ESR1, SELE, TIMP3, SMARCE1, TXNIP, and MRPS5 may be considered prognostic biomarkers for H. pylori–induced GC. However, experimental validation is necessary in the future.

Understanding the role of the gut microbiome in gastrointestinal cancer: A review

Gastrointestinal cancer represents one of the most diagnosed types of cancer. Cancer is a genetic and multifactorial disease, influenced by the host and environmental factors. It has been stated that 20% of cancer is caused by microorganisms such as Helicobacter pylori, hepatitis B and C virus, and human papillomavirus. In addition to these well-known microorganisms associated with cancer, it has been shown differences in the composition of the microbiota between healthy individuals and cancer patients. Some studies have suggested the existence of the selected microorganisms and their metabolites that can promote or inhibit tumorigenesis via some mechanisms. Recent findings have shown that gut microbiome and their metabolites can act as cancer promotors or inhibitors. It has been shown that gastrointestinal cancer can be caused by a dysregulation of the expression of non-coding RNA (ncRNA) through the gut microbiome. This review will summarize the latest reports regarding the relationship among gut microbiome, ncRNAs, and gastrointestinal cancer. The potential applications of diagnosing and cancer treatments will be discussed.

Chromatin and noncoding RNA-mediated mechanisms of gastric tumorigenesis

Gastric cancer (GC) is one of the most common and deadly cancers in the world. It is a multifactorial disease highly influenced by environmental factors, which include radiation, smoking, diet, and infectious pathogens. Accumulating evidence suggests that epigenetic regulators are frequently altered in GC, playing critical roles in gastric tumorigenesis. Epigenetic regulation involves DNA methylation, histone modification, and noncoding RNAs. While it is known that environmental factors cause widespread alterations in DNA methylation, promoting carcinogenesis, the chromatin- and noncoding RNA-mediated mechanisms of gastric tumorigenesis are still poorly understood. In this review, we focus on discussing recent discoveries addressing the roles of histone modifiers and noncoding RNAs and the mechanisms of their interactions in gastric tumorigenesis. A better understanding of epigenetic regulation would likely facilitate the development of novel therapeutic approaches targeting specific epigenetic regulators in GC.

Functional gene polymorphisms and expression alteration of selected microRNAs and the risk of various gastric lesions in Helicobacter pylori-related gastric diseases

Background: Helicobacter pylori (Hp) persistent infection is an important pathogenic factor for a series of chronic gastric diseases from chronic gastritis to gastric cancer. Genetic and epigenetic abnormalities of microRNAs may play a vital role in the pathological evolution of gastric mucosa in Helicobacter pylori-related gastric diseases (HPGD). This study aimed to investigate the relationship between miR-146a, miR-196a2, miR-149, miR-499 and miR-27a gene single nucleotide polymorphisms (SNPs) and their expressions with pathological changes in gastric mucosa, and to further analyze the interactions between SNPs and Hp. Methods: Subjects in this study included patients diagnosed with HPGD and healthy controls. MiR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs2292832, miR-499 rs3746444 and miR-27a rs895819 were genotyped by direct sequencing. Fluorescence quantitative PCR was used to detect microRNA expressions. Gene-gene and gene-environment interactions were evaluated by multifactor dimensionality reduction (MDR) method. Results: we found that frequency distribution of miR-196a2 rs11614913 CT genotype in gastric precancerous lesion (GPL) group and gastric cancer (GC) group was significantly higher than normal control (NOR) group [adjusted OR = 6.16, 95%CI (1.46-26.03); adjusted OR = 11.83, 95%CI (1.65-84.72), respectively]. CT genotype and C allele of miR-27a rs895819 were associated with increased risk of GC [adjusted OR = 10.14, 95%CI (2.25-45.77); adjusted OR = 3.71, 95%CI(1.46-9.44), respectively]. The MDR analysis results showed that the interaction between miR-196a2 rs11614913 and Hp was associated with the risk of GPL (p = 0.004). Meanwhile, the expression level of miR-196a2 in GC group was significantly higher than NOR, chronic inflammation (CI) and early precancerous lesion (EPL) groups among Hp-positive subjects. And expressions of miR-499 and miR-27a in GC group were both higher than EPL group. Also, miR-27a expression in GC group was higher than CI and gastric atrophy (GA) groups. Conclusion: miR-196a2 rs11614913 and miR-27a rs895819 may affect the genetic susceptibility to GPL or GC. MiR-196a2 rs11614913 and Hp have a synergistic effect in the occurrence and development of GPL. The up-regulation of miR-499, miR-196a2 and miR-27a expression caused by Hp infection may be an important mechanism of gastric carcinogenesis.

miR-638: A Promising Cancer Biomarker with Therapeutic Potential

BACKGROUND

There is an unmet need to improve the diagnosis of cancer with precise treatment strategies. Therefore, more powerful diagnostic, prognostic, and therapeutic biomarkers are needed to overcome tumor cells. microRNAs (miRNAs, miRs), as a class of small non-coding RNAs, play essential roles in cancer through the tumor-suppressive or oncogenic effects by post-transcriptional regulation of their targets. Many studies have provided shreds of evidence on aberrantly expressed miRNAs in numerous cancers and have shown that miRNAs could play potential roles as diagnostic, prognostic, and even therapeutic biomarkers in patients with cancers. Findings have revealed that miR-638 over or underexpression might play a critical role in cancer initiation, development, and progression. However, the mechanistic effects of miR-638 on cancer cells are still controversial.

CONCLUSION

In the present review, we have focused on the diagnostic, prognostic, and therapeutic potentials of miR-638 and discussed its mechanistic roles in various types of cancers.

Small Non-Coding RNAs in Human Cancer

Small non-coding RNAs are widespread in the biological world and have been extensively explored over the past decades. Their fundamental roles in human health and disease are increasingly appreciated. Furthermore, a growing number of studies have investigated the functions of small non-coding RNAs in cancer initiation and progression. In this review, we provide an overview of the biogenesis of small non-coding RNAs with a focus on microRNAs, PIWI-interacting RNAs, and a new class of tRNA-derived small RNAs. We discuss their biological functions in human cancer and highlight their clinical application as molecular biomarkers or therapeutic targets.

Circ_0008287 promotes immune escape of gastric cancer cells through impairing microRNA-548c-3p-dependent inhibition of CLIC1

BACKGROUND

Analyses in silico suggested the upregulation of a circular RNA (circRNA), circ_0008287, in gastric cancer and possible interactions among microRNA (miR)-548c-3p, circ_0008287, and intracellular chloride channel protein 1 (CLIC1). This study aims to testify whether circ_0008287 can affect the immune escape of gastric cancer cells by regulating miR-548c-3p and CLIC1.

METHODS

RT-qPCR was performed to determine the expression pattern of circ_0008287 in gastric cancer cells. Gain- and loss-of function assays were then performed to assess the effects of circ_0008287 on malignant phenotypes of cancer cells. Interactions among circ_0008287, miR-548c-3p and CLIC1 were verified by dual luciferase reporter gene, RIP and FISH assays. Effects of CLIC1 on IFN-γ secretion and apoptosis in CD8 + T cells were evaluated by flow cytometry following co-culture of CD8 + T cells with cancer cells overexpressing/silencing CLIC1. A gastric cancer mouse model was further developed for in vivo investigation on effects of circ_0008287 on tumorigenesis and tumor metastasis.

RESULTS

circ_0008287, an upregulated circRNA in gastric cancer cells, augmented the viability as well as invasive and migratory potentials of gastric cancer cells. By competitively binding to miR-548c-3, circ_0008287 increased the expression of CLIC1, which impaired the function of CD8 + T cells and promoted their apoptosis. After downregulation of circ_0008287, in vivo tumorigenesis and metastasis were suppressed.

CONCLUSION

Hence, this study suggests the promotive role of circ_0008287 in gastric cancer progression and immune escape and further elucidates the underlying circ_0008287/miR-548c-3p/CLIC1 regulatory axis.

Atrophic gastritis and gastric cancer tissue miRNome analysis reveals hsa-miR-129-1 and hsa-miR-196a as potential early diagnostic biomarkers

BACKGROUND

Gastric cancer (GC) is one of the most frequently diagnosed tumor globally. In most cases, GC develops in a stepwise manner from chronic gastritis or atrophic gastritis (AG) to cancer. One of the major issues in clinical settings of GC is diagnosis at advanced disease stages resulting in poor prognosis. MicroRNAs (miRNAs) are small noncoding molecules that play an essential role in a variety of fundamental biological processes. However, clinical potential of miRNA profiling in the gastric cancerogenesis, especially in premalignant GC cases, remains unclear.

AIM

To evaluate the AG and GC tissue miRNomes and identify specific miRNAs' potential for clinical applications (e.g., non-invasive diagnostics).

METHODS

Study included a total of 125 subjects: Controls (CON), AG, and GC patients. All study subjects were recruited at the Departments of Surgery or Gastroenterology, Hospital of Lithuanian University of Health Sciences and divided into the profiling (n = 60) and validation (n = 65) cohorts. Total RNA isolated from tissue samples was used for preparation of small RNA sequencing libraries and profiled using next-generation sequencing (NGS). Based on NGS data, deregulated miRNAs hsa-miR-129-1-3p and hsa-miR-196a-5p were analyzed in plasma samples of independent cohort consisting of CON, AG, and GC patients. Expression level of hsa-miR-129-1-3p and hsa-miR-196a-5p was determined using the quantitative real-time polymerase chain reaction and 2-ΔΔCt method.

RESULTS

Results of tissue analysis revealed 20 differentially expressed miRNAs in AG group compared to CON group, 129 deregulated miRNAs in GC compared to CON, and 99 altered miRNAs comparing GC and AG groups. Only 2 miRNAs (hsa-miR-129-1-3p and hsa-miR-196a-5p) were identified to be step-wise deregulated in healthy-premalignant-malignant sequence. Area under the curve (AUC)-receiver operating characteristic analysis revealed that expression level of hsa-miR-196a-5p is significant for discrimination of CON vs AG, CON vs GC and AG vs GC and resulted in AUCs: 88.0%, 93.1% and 66.3%, respectively. Compar-ing results in tissue and plasma samples, hsa-miR-129-1-3p was significantly down-regulated in GC compared to AG (P = 0.0021 and P = 0.024, tissue and plasma, respectively). Moreover, analysis revealed that hsa-miR-215-3p/5p and hsa-miR-934 were significantly deregulated in GC based on Helicobacter pylori (H. pylori) infection status [log2 fold change (FC) = -4.52, P-adjusted = 0.02; log2FC = -4.00, P-adjusted = 0.02; log2FC = 6.09, P-adjusted = 0.02, respectively].

CONCLUSION

Comprehensive miRNome study provides evidence for gradual deregulation of hsa-miR-196a-5p and hsa-miR-129-1-3p in gastric carcinogenesis and found hsa-miR-215-3p/5p and hsa-miR-934 to be significantly deregulated in H. pylori carrying GC patients.

Host miRNAs-microbiota interactions in gastric cancer

It is widely acknowledged that gastric cancer seriously affects the quality of life and survival of patients. The correlation between the microbiota and gastric cancer has attracted extensive attention in recent years, nonetheless the specific mechanism of its impact on gastric cancer remain largely unclear. Recent studies have shown that in addition to its role in the host’s inflammatory and immune response, the microbiota can also affect the occurrence and development of gastric cancer by affecting the expression of miRNAs. This paper brings together all currently available data on miRNAs, microbiota and gastric cancer, and preliminarily describes the relationship among them.

Extracellular vesicle microRNAs in celiac disease patients under a gluten-free diet, and in lactose intolerant individuals

BACKGROUND

Celiac disease (CD) is an autoimmune disorder triggered by an abnormal immunological response to gluten ingestion and is associated with deregulated expression of cellular microRNAs (miRNAs) of the gut mucosa. It is frequently misdiagnosed as lactose intolerance (LI) due to symptom resemblance. Microvilli loss may be counteracted by a rigorous gluten-free diet (GFD).

AIMS

To identify altered extracellular vesicle miRNAs from plasma among CD patients on GFD (n=34), lactose intolerant individuals on restrictive diet (n=14) and controls (n=23), and to predict biological pathways in which these altered miRNAs may play a part.

METHODS

Five different small RNA samples of each group were pooled twice and then screened by new-generation sequencing. Four miRNAs were selected to be quantified by RT-qPCR in the entire sample.

RESULTS

The levels of four miRNAs - miR-99b-3p, miR-197-3p, miR-223-3p, and miR-374b-5p - differed between CD patients and controls (P<0.05). Apart from miR-223-3p, all these miRNAs tended to have altered levels also between LI and controls (P<0.10). The results for miR-99b-3p and miR-197-3p between CD and controls were confirmed by RT-qPCR, which also indicated different levels of miR-99b-3p and miR-374b-5p between CD-associated LI and LI (P<0.05).

CONCLUSIONS

These miRNAs may have targets that affect cell death, cell communication, adhesion, and inflammation modulation pathways. Hence, altered miRNA levels could be associated with CD-related aspects and gut mucosa recovery.

Investigating Helicobacter pylori-related pyloric hypomotility: functional, histological, and molecular alterations

Multiple theories have been proposed describing the pathogenic mechanisms of Helicobacter pylori (H. pylori)-associated gastric motility disorders. We assessed ex vivo pyloric activity in H. pylori-infected rats, and tried to explore the associated ghrelin hormone alteration and pyloric fibrogenesis. In addition, miR-1 was assessed in pyloric tissue samples, being recently accused of having a role in smooth muscle dysfunction. Ninety adult male Wistar albino rats were assigned into nine groups: 1) control group, 2) sterile broth (vehicle group), 3) amoxicillin control, 4) omeperazole control, 5) clarithromycin control, 6) triple therapy control, 7) H. pylori- group, 8) H. pylori-clarithromycin group, and 9) H. pylori-triple therapy group. Urease enzyme activity was applied as an indicator of H. pylori infection. Ex vivo pyloric contractility was evaluated. Serum ghrelin was assessed, and histological tissue evaluation was performed. Besides, pyloric muscle miR-1 expression was measured. The immunological epithelial to mesenchymal transition (EMT) markers; transforming growth factor β (TGFβ), α-smooth muscle actin (α-SMA), and E-cadherin-3 were also evaluated. By H. pylori infection, a significant (P < 0.001) reduced pyloric contractility index was recorded. The miR-1 expression was decreased (P < 0.001) in the H. pylori-infected group, associated with reduced serum ghrelin, elevated TGFβ, and α-SMA levels and reduced E-cadherin levels. Decreased miR-1 and disturbed molecular pattern were improved by treatment. In conclusion, H. pylori infection was associated with reduced miR-1, epithelial to mesenchymal transition, and pyloric hypomotility. The miR-1 may be a target for further studies to assess its possible involvement in H. pylori-associated pyloric dysfunction, which might help in the management of human H. pylori manifestations and complications.NEW & NOTEWORTHY This work is investigating functional, histopathological, and molecular changes underlying Helicobacter pylori hypomotility and is correlating these with miR-1, whose disturbance is supposed to be involved in smooth muscle dysfunction and cell proliferation according to literature. Epithelial to mesenchymal transition and reduced ghrelin hormone may contribute to H. pylori infection-associated hypomotility. H. pylori infection was associated with reduced pyloric miR-1 expression. Targeting miR-1 could be valuable in the clinical management of pyloric hypofunction.

Effects and prognostic values of miR-30c-5p target genes in gastric cancer via a comprehensive analysis using bioinformatics

Gastric cancer (GC) is a common cancer and the leading cause of cancer-related death worldwide. To improve the diagnosis and treatment of GC, it is necessary to identify new biomarkers by investigating the cellular and molecular mechanisms. In this study, miR-30c-5p expression was significantly down-regulated in GC tissues by comprehensive analysis using multiple databases. The target genes of miR-30c-5p with up-regulated expression level in GC were identified, including ADAM12 (a disintegrin and metalloproteinase12), EDNRA (the Endothelin receptor type A), STC1 (stanniocalcin 1), and CPNE8 (the calcium-dependent protein, copine 8). The expression level of ADAM12 was significantly related to depth of invasion (p = 0.036) in GC patients. The expression level of EDNRA was significantly related to grade (P = 0.003), depth of invasion (P = 0.019), and lymphatic metastasis (P = 0.001). The expression level of CPNE8 was significantly related to grade (P = 0.043) and TNM stage (P = 0.027).Gene set enrichment analysis showed that they might participate in GC progression through cancer-related pathways. CIBERSORT algorithm analysis showed that their expressions were related to a variety of tumor-infiltrating immune cells. The higher expression of those target genes might be the independent risk factor for poor survival of GC patients, and they might be potential prognostic markers in GC patients.

MicroRNA-Based Risk Score for Predicting Tumor Progression Following Radioactive Iodine Ablation in Well-Differentiated Thyroid Cancer Patients: A Propensity-Score Matched Analysis

Simple Summary

The three-tiered American Thyroid Association (ATA) risk stratification helps clinicians tailor decisions regarding follow-up modalities and the need for postoperative radioactive iodine (RAI) ablation and radiotherapy. However, a significant number of well-differentiated thyroid cancers (DTC) progress after treatment. Current follow-up modalities have also been proposed to detect disease relapse and recurrence but have failed to be sufficiently sensitive or specific to detect, monitor, or determine progression. Therefore, we assessed the predictive accuracy of the microRNA-based risk score in DTC with and without postoperative RAI. We confirm the prognostic role of triad biomarkers (miR-2f04, miR-221, and miR-222) with higher sensitivity and specificity for predicting disease progression than the ATA risk score. Compared to indolent tumors, a higher risk score was found in progressive samples and was associated with shorter survival. Consequently, our prognostic microRNA signature and nomogram provide a clinically practical and reliable ancillary measure to determine the prognosis of DTC patients.

Abstract

To identify molecular markers that can accurately predict aggressive tumor behavior at the time of surgery, a propensity-matching score analysis of archived specimens yielded two similar datasets of DTC patients (with and without RAI). Bioinformatically selected microRNAs were quantified by qRT-PCR. The risk score was generated using Cox regression and assessed using ROC, C-statistic, and Brier-score. A predictive Bayesian nomogram was established. External validation was performed, and causal network analysis was generated. Within the eight-year follow-up period, progression was reported in 51.5% of cases; of these, 48.6% had the T1a/b stage. Analysis showed upregulation of miR-221-3p and miR-222-3p and downregulation of miR-204-5p in 68 paired cancer tissues (p < 0.001). These three miRNAs were not differentially expressed in RAI and non-RAI groups. The ATA risk score showed poor discriminative ability (AUC = 0.518, p = 0.80). In contrast, the microRNA-based risk score showed high accuracy in predicting tumor progression in the whole cohorts (median = 1.87 vs. 0.39, AUC = 0.944) and RAI group (2.23 vs. 0.37, AUC = 0.979) at the cutoff >0.86 (92.6% accuracy, 88.6% sensitivity, 97% specificity) in the whole cohorts (C-statistics = 0.943/Brier = 0.083) and RAI subgroup (C-statistic = 0.978/Brier = 0.049). The high-score group had a three-fold increased progression risk (hazard ratio = 2.71, 95%CI = 1.86–3.96, p < 0.001) and shorter survival times (17.3 vs. 70.79 months, p < 0.001). Our prognostic microRNA signature and nomogram showed excellent predictive accuracy for progression-free survival in DTC.

Helicobacter pylori induces gastric cancer via down-regulating miR-375 to inhibit dendritic cell maturation

BACKGROUND

Recent studies and clinical samples have demonstrated that Helicobacter pylori could induce the downregulation of miR-375 in the stomach and promote gastric carcinogenesis. However, whether the immune cells are affected by Helicobacter pylori due to the downregulation of miR-375 is unclear.

MATERIALS AND METHODS

In this study, we constructed an overexpression and knockdown of miR-375 and Helicobacter pylori infection cell models in vitro. In addition, the maturity of dendritic cells (DCs) and the expression of IL-6, IL-10, and VEGF at the transcriptional and translational levels were analyzed. Changes in the JAK2-STAT3 signaling pathway were detected. In vivo, the number changes in CD4+ T and CD8+ T cells and the size changes of tumors via models of transplantable subcutaneous tumors were also analyzed.

RESULTS

A cell model of Helicobacter pylori and gastric cancer was used to identify the expression of miR-375 and the maturity of dendritic cells. This study found that Helicobacter pylori could downregulate miR-375, which regulates the expression of cytokines IL-6, IL-10, and VEGF in the stomach. MiR-375 regulated the expression of cytokines IL-6, IL-10, and VEGF through the JAK2-STAT3 signaling pathway in vitro. In addition, we found that Helicobacter pylori regulates the maturation of dendritic cells through miR-375. These results were further verified in vivo, and miR-375 diminishes tumor size was also demonstrated. This study showed that immature DCs caused a decrease in the number of CD4+ and CD8+ T cells.

CONCLUSIONS

This study demonstrated that Helicobacter pylori can inhibit miRNA-375 expression in the stomach. Downregulated miR-375 activates the JAK2-STAT3 pathway. Activating the JAK2-STAT3 signaling pathway promotes the secretion of IL-6, IL-10, and VEGF, leading to immature differentiation of DCs and induction of gastric cancer.

Expression Profile of miRNA-17-3p and miRNA-17-5p Genes in Gastric Cancer Patients with Helicobacter pylori Infection

BACKGROUND

The most common chronic bacterial infection is Helicobacter pylori. The connection between chronic H. pylori infection and gastric cancer is recognized. The early detection of gastric cancer improves survival. miRNAs regulate gene expression in eukaryotes by inhibiting mRNA translocation or degradation. The objective of this study was to compare the expression of miRNA-17-3p and miRNA-17-5p genes in gastric cancer patients with Helicobacter pylori infection.

METHODS

Herein, 30 isolates were identified as H. pylori based on urease test, and 30 and 12 cases were isolated from gastric cancer patients and non-Helicobacter pylori cases as control, respectively. A peripheral blood sample was collected from patients. Analysis of total mRNA extracts from peripheral blood samples, for gene expression changes (miRNA-17-3p and miRNA-17-5p) by quantitative real-time polymerase chain reaction (qRT-PCR), was done.

RESULTS

As said by the results, p values showed that expression levels of miRNA-17-3p and miRNA-17-5p were significantly higher in H. pylori-positive GC patients and H. pylori-positive non-GC patients with comparing by healthy controls. So, there was no significant difference between expression levels of miRNA-17-3p and miRNA-17-5p in H. pylori-positive GC patients and H. pylori-positive non-GC patients.

CONCLUSION

Considering our results, the high expression of miRNA-17-3p and miRNA-17-5p has a direct relationship with increased cell proliferation, inhibition of tumor cell apoptosis and tumor angiogenesis, in addition to miRNAs play an important role as biomarkers in helping for detection of the patient by H. pylori infection to become cancerous. Therefore, it can be used to make specific diagnostic kits and to treat patients.

Vitamin D modulation and microRNAs in gastric cancer: prognostic and therapeutic role

Gastric adenocarcinoma arises after a complex interaction between the host and environmental factors. Tumor location and TNM are the tools that currently guide treatment decisions. Surgery is the only curative treatment, but relapse is common. After relapse or advanced staged disease survival is poor and systemic treatment has modestly improved survival. An association between sun exposure, vitamin D status and gastric cancer (GC) incidence and mortality has been reported. The molecular differences of the histological subtypes and the new molecular classifications account for the great heterogeneity of this disease and are the basis for the discovery of new therapeutic targets. New prognostic and predictive factors are essential and microRNAs (miRNAs) are endogenous small non-coding RNA molecules with a great potential for diagnosis, prognosis and treatment of cancer. There are hundreds of miRNAs with altered expression in tumor gastric tissue when compared to normal gastric tissue. Many of these miRNAs are associated with clinicopathological variables and survival in patients with GC. Furthermore, the expression of some of these miRNAs with prognostic importance in CG is influenced by vitamin D and others are mediators of some of the actions of this vitamin. This review aims to update the evidence on several miRNAs with prognostic value and therapeutic potential in GC, whose expression may be influenced by vitamin D or may regulate vitamin D signaling.

Oncogenesis and Tumor Inhibition by MicroRNAs and its Potential Therapeutic Applications: A Systematic Review

MicroRNAs appear as small molecule modifiers, which improve many new findings and mechanical illustrations for critically important biological phenomena and pathologic events. The best-characterized non-coding RNA family consists of about 2600 human microRNAs. Rich evidence has revealed their crucial importance in maintaining normal development, differentiation, growth control, aging, modulation of cell survival or apoptosis, as well as migration and metastasis as microRNAs dysregulation leads to cancer incidence and progression. By far, microRNAs have recently emerged as attractive targets for therapeutic intervention. The rationale for developing microRNA therapeutics is based on the premise that aberrantly expressed microRNAs play a significant role in the emergence of a variety of human diseases ranging from cardiovascular defects to cancer, and that repairing these microRNA deficiencies by either antagonizing or restoring microRNA function may yield a therapeutic benefit. Although microRNA antagonists are conceptually similar to other inhibitory therapies, improving the performance of microRNAs by microRNA replacement or inhibition that is a less well- described attitude. In this assay, we have condensed the last global knowledge and concepts regarding the involvement of microRNAs in cancer emergence, which has been achieved from the previous studies, consisting of the regulation of key cancer-related pathways, such as cell cycle control and the DNA damage response and the disruption of profile expression in human cancer. Here, we have reviewed the special characteristics of microRNA replacement and inhibition therapies and discussed explorations linked with the delivery of microRNA mimics in turmeric cells. Besides, the achievement of biomarkers based on microRNAs in clinics is considered as novel non-invasive biomarkers in diagnostic and prognostic assessments.

Gastric cancer-associated microRNA expression signatures: integrated bioinformatics analysis, validation, and clinical significance

Background

Gastric cancer (GC) is one of the common gastrointestinal malignancy worldwide and exhibits a poor prognosis. Increasing studies have indicated that microRNAs play critical roles in the cancer progression and have shown great potential as useful biomarkers. The search for potential diagnostic and prognostic biomarkers of gastric cancer (GC) with integrated bioinformatics analyses has been undertaken in previous studies.

Methods

In this study, the robust rank aggregation (RRA) method was used to perform an integrated analysis of differentially expressed miRNAs (DEMs) from five microarray datasets in the Gene Expression Omnibus (GEO) database to find robust biomarkers for GC. Ultimately, seven miRNAs were filtered from fourteen primary miRNAs using the validation set of The Cancer Genome Atlas (TCGA) database. Based on these results, diagnostic and survival analyses were performed, and logistic regression and Cox regression were used to determine the clinicopathological characteristics of the DEM expression and overall survival.

Results

Nine eligible miRNA datasets related to GC were selected from the GEO database for integrated analysis in this study. Diagnostic analysis implied that these miRNAs could be regarded as promising candidate diagnostic biomarkers in GC tissues, but whether the results of the tissue analysis are consistent with those of peripheral blood analysis requires further validation. The logistic regression indicated that the ectopic expression of these DEMs was relevant to the histological type, anatomical region, and pathological grade of GC. However, the survival and Cox regression analyses suggested that the poor prognosis of GC patients was not strongly dependent on the ectopic expression of the seven miRNAs, but rather, a poor prognosis was associated with age, metastasis, and histological grade.

Conclusions

Based on the results presented in this study it can be concluded that these miRNAs (miR-455-3p, miR-135b-5p, let-7a-3p, miR-195-5p, miR-204-5p, miR-149-5p, and miR-143-3p) might be potential biomarkers for the early diagnosis of GC patients, but this finding should be regarded with caution. A large-scale, prospective, and multicenter cohort study should be performed.

Association of sonic hedgehog signaling pathway genes IHH, BOC, RAB23a and MIR195-5p, MIR509-3-5p, MIR6738-3p with gastric cancer stage

Gastric cancer is the leading cause of cancer-related mortality worldwide. Given the importance of gastric cancer in public health, identifying biomarkers associated with disease onset is an important part of precision medicine. The hedgehog signaling pathway is considered as one of the most significant widespread pathways of intracellular signaling in the early events of embryonic development. This pathway contributes also to the maintenance of pluripotency of cancer stem cells pluripotency. In this study, we analyzed the expression levels of sonic hedgehog (Shh) signaling pathway genes IHH, BOC, RAB23a and their regulatory miRNAs including MIR-195-5p, MIR-509-3-5p, MIR-6738-3p in gastric cancer patients. In addition, the impact of infection status on the expression level of those genes and their regulatory miRNAs was investigated. One hundred samples taken from 50 gastric cancer patients (50 tumoral tissues and their adjacent non-tumoral counterparts) were included in this study. There was a significant difference in all studied genes and miRNAs in tumoral tissues in comparison with their adjacent non-tumoral counterparts. The lower expression of IHH, BOC, RAB23, miR-195-5p, and miR-6738-3p was significantly associated with more advanced cancer stage. Additionally, IHH upregulation was significantly associated with CMV infection (P < 0.001). Also, receiver operating characteristic (ROC) curve analysis indicated that mir-195 was significantly related to several clinicopathological features including tumor stage, grade, age, gender, and infection status of gastric cancer and can be considered as a potential diagnostic biomarker for gastric cancer. This study confirms the important role of Shh signaling pathway genes in gastric cancer tumorigenesis and their potential as novel molecular biomarkers and therapeutic targets.

MicroRNA-99 family in cancer and immunity

The microRNA (miR)-99 family comprising miR-99a, miR-99b, and miR-100 is an evolutionarily conserved family with existence dating prior to the bilaterians. Members are typically oncogenic in leukemia while their functional roles in other cancers alternate between that of a tumor suppressor and a tumor promoter. Targets of the miR-99 family rank in the lists of oncogenes and tumor suppressors, thereby illustrating the dual role of this miR family as oncogenic miRs (oncomiRs) and tumor suppressing miRs (TSmiRs) in different cellular contexts. In addition to their functional roles in cancers, miR-99 family is implicated in the modulation of macrophage inflammatory responses and T-cell subsets biology, thereby exerting critical roles in the maintenance of tissue homeostasis, establishment of peripheral tolerance as well as resolution of an inflammatory reaction. Here, we review emerging knowledge of this miR family and discuss remaining concerns linked to their activities. A better dissection of the functional roles of miR-99 family members in cancer and immunity will help in the development of novel miR-99-based therapeutics for the treatment of human cancer and immune-related diseases. This article is categorized under: RNA in Disease and Development > RNA in Disease.

MiR-548c-3p inhibits the proliferation, migration and invasion of human breast cancer cell by targeting E2F3

MiR-548 has been reported to be involved in a variety of tumor processes, but its function in breast cancer remains unclear. In this study, we found that miR-548 was low expressed in breast cancer tissues and cells compared with normal control. We then examined whether up-regulation of miR-548 could improve the progression of breast cancer. Our results indicate that up-regulation of miR-548 significantly inhibits cell proliferation, migration andinvasion, and induces apoptosis in breast cancer cells. Further studies showed that miR-548 could specifically inhibit E2F3 expression. Moreover, rescue test showed that up-regulation of E2F2 could reverse the effect of miR-548 on proliferation, migration, invasion and apoptosis of breast cancer cells. In general, miR-548 could improve the progression of breast cancer. By targeting E2F2, which may make a potential target for the treatment of breast cancer.

LINC00266-1/miR-548c-3p/SMAD2 feedback loop stimulates the development of osteosarcoma

Osteosarcoma (OS) is one of the most common primary bone malignancies and accounts for 3.4% of pediatric tumors. Its 5-year survival is as low as about 20%. Differentially expressed lncRNAs in OS profiling were searched in the downloaded profile of GSE12865. As a result, LINC00266-1 was detected to be upregulated in both GSE12865 and OS tissues we collected. SMAD2 was the downstream target binding to promoter sites of LINC00266-1, displaying a positive regulatory interaction. Knockdown of LINC00266-1 suppressed the proliferative and metastatic abilities, and promoted the apoptosis in OS cells. Besides, knockdown of LINC00266-1 significantly alleviated the growth of OS in vivo. MiR-548c-3p was the sponge miRNA of LINC00266-1, which was able to reverse the regulatory effects of LINC00266-1 on OS cell phenotypes. Moreover, miR-548c-3p bound to the 3'-UTR of SMAD2 and thus downregulated SMAD2. Overexpression of SMAD2 partially reversed the regulatory effects of LINC00266-1 on OS cell phenotypes. Finally, we have identified that LINC00266-1/miR-548c-3p/SMAD2 feedback loop was responsible for stimulating the development of OS.

Long non-coding RNA NPBWR1-2 affects the development of ovarian cancer via multiple microRNAs

Ovarian cancer has a high incidence rate and mortality in gynaecologic malignancies. Epithelial ovarian cancer (EOC) accounts for >95% of ovarian cancer cases. Most of the patients with EOC are difficult to diagnose in early stage. The aim of the present study was to compare the long non-coding (lnc)RNA expression profiles of five ovarian cancer cell lines (IGROV1, A2780, SKOV3, ES2, and Hey) and an ovarian epithelial cell line (IOSE80) in order to identify differentially expressed lncRNAs and their associated microRNAs (miRNAs). The expression profiles of lncRNAs and mRNAs in these cell lines were determined by microarray gene analysis and reverse transcription-quantitative PCR. lncRNA neuropeptides B and W receptor 1–2 (NPBWR1-2) overexpression was induced in the SKOV3 cell line. Cell viability, proliferation, migration, invasion and apoptosis were evaluated using MTT, colony-formation, Transwell and flow cytometry assays, respectively. The microarray results indicated that several lncRNAs were differentially expressed in the five ovarian cancer cell lines compared with the normal ovarian epithelial cell line. Compared with IOSE80, lncRNA NPBWR1-2 was downregulated by more than two-fold in all five ovarian cancer cell lines. Moreover, NPBWR1-2 overexpression in the SKOV3 cell line decreased cell viability, inhibited proliferation, migration and invasion, and promoted apoptosis compared with the control cells. A total of 20 miRNAs, which are involved in tumorigenesis and development, were predicted to be associated with NPBWR1-2 by bioinformatics analysis. The results of the present study suggest that lncRNA NPBWR1-2 affects the occurrence and development of ovarian cancer via multiple miRNAs, providing a theoretical basis for the development of novel clinical treatments.

Peripheral blood mononuclear cell microRNA profiles in syphilitic patients with serofast status

Syphilis is a chronic sexually transmitted disease caused by infection with Treponema pallidum, which can invade various system organs, leading to clinical manifestations such as neurosyphilis, ocular syphilis, and cardiovascular syphilis and seriously endangering human health. Serofast status is a common outcome after syphilis treatment that presents an important clinical problem. At present, the etiology of serofast status remains unknown. A systematic investigation of the microRNA (miRNA) expression profiles in peripheral blood mononuclear cells (PBMCs) of patients with serofast status or secondary syphilis and of healthy control subjects was conducted using small RNA-seq. The expression of miRNAs was further confirmed by real-time fluorescence quantitative PCR (qPCR) assays. The data reveal a specific miRNA expression profile that was displayed in cells from patients with serofast status. Known and novel predicted (np)-miRNAs were also identified and verified, such as miR-338-5p, np-miR-163, np-miR-128, np-miR-244, and np-miR-5, which together may be used as indicators for treatment evaluation. The functions of genes targeted by the miRNAs differentially expressed in serofast status patients were further analyzed; these genes were found to be involved in various biological functions, such as T-cell receptor signaling pathways, metabolism, and growth. Our study presents the first systematic landscape of miRNAs in PBMCs from patients with serofast status and proposes specific miRNAs linked with serofast status. Our results provide further evidence that serofast status is closely related to host immune function. Additionally, the miRNA expression profile in PBMCs of patients with serofast status generated by this work offers insight into the complex immune network in humans. We hope our results can provide new insights into the pathogenesis of serofast status.

Comprehensive analysis of Helicobacter pylori infection-associated diseases based on miRNA-mRNA interaction network

Helicobacter pylori (H. pylori) infection remains a cause of significant morbidity and mortality worldwide. Comprehensive understanding of the pathogenic mechanism of H. pylori and its interaction with host will contribute to developing novel prophylactical and therapeutical strategies. Here, we first determined microRNA (miRNA) levels in H. pylori-infected patients with gastritis, duodenal ulcer, gastric cancer or mucosa-associated lymphoid tissue lymphoma using miRNA data sets. Thirty-four differentially expressed miRNAs were identified and functional enrichment analysis of those miRNA target genes revealed that H. pylori infection were strongly associated with pathway in cancer and regulation of mRNA synthesis. Using disease connectivity analysis of 28 hub genes, we found that H. pylori may increase the risk of many extragastric diseases (e.g. cardiovascular disease, hemic and lymphatic diseases and nervous system disease). Altogether, our integrated analysis provided a new method to predict pathogen–human disease connectivity based on miRNA-mRNA interaction network and indicated anti-H. pylori therapy as an effective means of human diseases prevention.

[Effect of miR-204-5p on the proliferation, migration, and invasion on tongue squamous cell carcinoma SCC25 cells by targeting bromodomain-containing protein 4]

OBJECTIVE

This study aimed to explore the target relationship between miR-204-5p and bromodomain-containing protein (BRD) 4, as well as their effects on cell proliferation, migration, and invasion in tongue squamous cell carcinoma SCC25.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) was performed to detect miR-204-5p and BRD4 expression levels in tongue squamous cell carcinoma and different cell lines. TargetScan and dual luciferase reporter assay were used to confirm the target relationship between miR-204-5p and BRD4. The effects of miR-204-5p on SCC25 cell proliferation were examined by cell counting kit (CCK) 8 assay, whereas those on SCC25 cell migration and invasion were determined by Transwell assay. RT-qPCR and Western blot were used to detect the effects of miR-204-5p mimics and inhibitors on BRD4 expression. Transwell and CCK8 assays were used to detect the effects of miR-204-5p on proliferation, migration, and invasion through BRD4 regulation.

RESULTS

miR-204-5p was significantly downregulated in the tissues and cells of squamous cell carcinoma, and BRD4 showed the opposite result. The increase in miR-204-5p expression can inhibit the proliferation, migration, and invasion of SCC25 cells. TargetScan and luciferase test confirmed that miR-204-5p and BRD4 had a negative regulatory relationship with BRD4, respectively. Moreover, miR-204-5p mimics can inhibit BRD4 expression, and miR-204-5p inhibitors can promote BRD4 expression upregulation. When miR-204-5p and BRD4 were overexpressed in SCC25 cells, BRD4 can make up for the inhibitory effect of miR-204-5p on SCC25 cells.

CONCLUSIONS

miR-204-5p could inhibit proliferation, migration and invasion in tongue squamous cell carcinoma SCC25 cells by targeting BRD4 gene.

miR-204-5p Suppress Lymph Node Metastasis via Regulating CXCL12 and CXCR4 in Gastric Cancer

Gastric cancer (GC) exhibits a poor prognosis due to extensive invasion and lymphatic metastasis in the advanced stage. In this study, we firstly found that the expression of miR-204-5p markedly decreased in GC patients' tissue and serum, especially in GC with lymphatic metastasis. And ROC analysis showed miR-204-5p also served as a predicted factor for the lymphatic metastasis of GC. CXCL12 and CXCR4 were predicted and confirmed as the functional targets of miR-204-5p by Targetscan analysis, dual luciferase assay and western blotting analysis. In addition, we further determined that miR-204-5p suppresses migration and invasion in GC. This finding elucidates new functions and mechanisms for miR-204-5p in GC development and provides a new potential diagnostic marker and therapeutic targets for GC.

Helicobacter pylori Dampens HLA-II Expression on Macrophages via the Up-Regulation of miRNAs Targeting CIITA

Macrophages have a major role in infectious and inflammatory diseases, and the available data suggest that Helicobacter pylori persistence can be explained in part by the failure of the bacterium to be killed by professional phagocytes. Macrophages are cells ready to kill the engulfed pathogen, through oxygen-dependent and -independent mechanisms; however, their killing potential can be further augmented by the intervention of T helper (Th) cells upon the specific recognition of human leukocyte antigen (HLA)-II-peptide complexes on the surface of the phagocytic cells. As it pertains to H. pylori, the bacterium is engulfed by macrophages, but it interferes with the phagosome maturation process leading to phagosomes with an altered degradative capacity, and to megasomes, wherein H. pylori resists killing. We recently showed that macrophages infected with H. pylori strongly reduce the expression of HLA-II molecules on the plasma membrane and this compromises the bacterial antigen presentation to Th lymphocytes. In this work, we demonstrate that H. pylori hampers HLA-II expression in macrophages, activated or non-activated by IFN-γ, by down-regulating the expression of the class II major histocompatibility complex transactivator (CIITA), the "master control factor" for the expression of HLA class II genes. We provided evidence that this effect relies on the up-regulation of let-7f-5p, let-7i-5p, miR-146b-5p, and -185-5p targeting CIITA. MiRNA expression analysis performed on biopsies from H. pylori-infected patients confirmed the up-regulation of let-7i-5p, miR-146b-5p, and -185-5p in gastritis, in pre-invasive lesions, and in gastric cancer. Taken together, our results suggest that specific miRNAs may be directly involved in the H. pylori infection persistence and may contribute to confer the risk of developing gastric neoplasia in infected patients.

Differentiation of H. pylori-negative and positive gastric cancer via regulatory network analysis

AIM

To understand the molecular difference between H.pylori negative and positive gastric cancer, a regulatory network analysis is investigated.

BACKGROUND

Helicobacter pylori as the one of the most leading causes of gastric cancer is yet to be studied in terms of its molecular pathogenicity.

METHODS

Cytoscape version of 3.7.2 with its applications was employed to conduct this study via corresponding algorithms.

RESULTS

A total of 161 microRNAs were identified differentially expressed in the comparison of two groups of gastric cancer including negative and positive with H.pylori infection. CluePedia explored the regulatory network and found down-regulation dominant while considering the linked hub genes.

CONCLUSION

It can be concluded that the presented microRNAs and target genes could have associations with H.pylori carcinogenesis in gastric cancer through dysregulation of some vital biological processes. These microRNAs and target genes include hsa-miR-943, hsa-miR-935, hsa-miR-367, hsa-miR-363, hsa-miR-25, and hsa-miR-196b and ADRA1A, KCNA4, SOD1, and SESN3, respectively. However, verification analysis in this regard is required to establish these relationships.

The Prognostic and Predictive Value of microRNAs in Patients with H. pylori-positive Gastric Cancer

Gastric cancer (GC) has a high mortality rate with a poor 5-year survival. Helicobacter pylori (H. pylori) is present as part of the normal flora of stomach. It is found in the gastric mucosa of more than half of the world population. This bacterium is involved in developing H. pylori-induced GC due to the regulation of different micro ribonucleic acid (miRNA or miR). miRNAs are small noncoding RNAs and are recognized as prognostic biomarkers for GC that may control gene expression. miRNAs may function as tumor suppressors, or oncogenes. In this review, we evaluated studies that investigated the ectopic expression of miRNAs in the prognosis of H. pylori positive and negative GC.

Downregulated Expression of hsa_circ_0005556 in Gastric Cancer and Its Clinical Significance

Background

Gastric cancer (GC) has a poor prognosis due to the lack of ideal tumor markers. Circular RNAs (circRNAs) are a novel type of noncoding RNA related to the occurrence of GC. Among our research, we investigated the role of hsa_circ_0005556 in GC.

Materials and Methods

The expression of hsa_circ_0005556 of 100 paired GC tissues and adjacent normal tissues was detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). A receiver operating characteristic (ROC) curve was established to evaluate the diagnostic value of hsa_circ_0005556. The correlation between the expression of hsa_circ_0005556 and corresponding clinicopathological characteristic was explored.

Results

hsa_circ_0005556 was significantly downregulated in GC tissues contrasted with adjacent normal tissues (n = 100, p < 0.001). The areas under the ROC curve (AUC) of hsa_circ_0005556 were up to 0.773, while 64% sensitivity and 82% specificity, respectively. Moreover, its expression levels were significantly associated with differentiation (p = 0.001), TNM stage (p = 0.013), and lymphatic metastasis (p = 0.039). GC patients of high hsa_circ_0005556 levels had a longer overall survival (OS) than those of the low group (p = 0.047).

Conclusion

hsa_circ_0005556 is a potential biomarker for GC, which may guide judgment of the indication of endoscopic treatment for early gastric cancer (EGC).

SIRT1-targeted miR-543 autophagy inhibition and epithelial-mesenchymal transition promotion in Helicobacter pylori CagA-associated gastric cancer

Gastric cancer is an important cause of death worldwide with Helicobacter pylori (H. pylori) considered a leading and known risk factor for its development. More particularly and despite the underlying mechanisms not being very clear, studies have revealed that the H. pylori cytotoxin-associated gene A (CagA) protein plays a key role in this process. In this study it was found that H. pylori increased the expression of miR-543 in human gastric cancer tissue when compared with H. pylori-negative gastric cancer tissue samples. In vitro experiments showed that increased expression of miR-543 induced by CagA is a strong promoter of cell proliferation, migration, and invasion. Conversely, a miR-543 inhibitor suppressed or reversed these effects. It was furthermore found that silencing miR-543 inhibited autophagy and led to epithelial-mesenchymal transition (EMT) under in vitro. The mechanisms by which miR-543 targets SIRT1 to downregulate autophagy was also described. The results suggest that in the progression of H. pylori-associated gastric cancer, CagA induces overexpression of miR-543, which subsequently targets SIRT1 to suppress autophagy. This may be followed by increased expression of EMT causing cell migration and invasion. Consequently, miR-543 might be considered a therapeutic target for H. pylori-associated gastric cancer.

Identification of long noncoding RNA RP11-169F17.1 and RP11-669N7.2 as novel prognostic biomarkers of stomach adenocarcinoma based on integrated bioinformatics analysis

Aim: We aim to identify differentially expressed long noncoding RNAs (lncRNAs) and explored their functional roles in stomach adenocarcinoma. Materials & methods: Based on public omics data, we identified disregulated lncRNAs and investigated their prognostic values and potential functions based on ceRNA hypothesis. Results: Among the 52 differentially expressed lncRNAs, upregulated RP11-169F17.1 and RP11-669N7.2 were significantly associated with both poor overall survival and disease-free survival. RP11-169F17.1 and RP11-669N7.2 strongly correlated with microRNAs in cancer, cell proliferation and differentiation. RP11-169F17.1 and RP11-669N7.2 closely related to Helicobacter pylori infection-induced gastritis, duodenal ulcer, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Conclusion: RP11-169F17.1 and RP11-669N7.2 act as novel prognostic biomarkers of stomach adenocarcinoma and may also play an important role in H. pylori infection-induced gastric diseases.

Regulation of GKN1 expression in gastric carcinogenesis: A problem to resolve (Review)

Gastrokine 1 (GKN1) is a protein expressed on the surface mucosa cells of the gastric antrum and fundus, which contributes to maintaining gastric homeostasis, inhibits inflammation and is a tumor suppressor. The expression of GKN1 decreases in mucosa that are either inflamed or infected by Helicobacter pylori, and is absent in gastric cancer. The measurement of circulating GKN1 concentration, the protein itself, or the mRNA in gastric tissue may be of use for the early diagnosis of cancer. The mechanisms that modulate the deregulation or silencing of GKN1 expression have not been completely described. The modification of histones, methylation of the GKN1 promoter, or proteasomal degradation of the protein have been detected in some patients; however, these mechanisms do not completely explain the absence of GKN1 or the reduction in GKN1 levels. Only NKX6.3 transcription factor has been shown to be a positive modulator of GKN1 transcription, although others also have an affinity with sequences in the promoter of this gene. While microRNAs (miRNAs) are able to directly or indirectly regulate the expression of genes at the post‑transcriptional level, the involvement of miRNAs in the regulation of GKN1 has not been reported. The present review analyzes the information reported on the determination of GKN1 expression and the regulation of its expression at the transcriptional, post‑transcriptional and post‑translational levels; it proposes an integrated model that incorporates the regulation of GKN1 expression via transcription factors and miRNAs in H. pylori infection.

Circ-SERPINE2 promotes the development of gastric carcinoma by sponging miR-375 and modulating YWHAZ

Objectives

Circular RNAs (circRNAs) exist extensively in the eukaryotic genome. The study aimed to identify the role of hsa_circ_0008365 (Circ‐SERPINE2) in gastric carcinoma (GC) cells and its downstream mechanisms.

Materials and methods

Gene Expression Omnibus (GEO) database was applied to screen differentially expressed circRNAs. CircInteractome, TargetScan and miRecords websites were used to predict target relationships. qRT‐PCR and RNase R treatment were utilised to detect molecule expression and confirm the existence of circ‐SERPINE2. RNA pull‐down assay and dual‐luciferase reporter assay were performed for interaction between circRNA and miRNA or mRNA. EdU assay, colony formation assay, and flow cytometry for apoptosis and cell cycle detections were utilised to assess cell function. Western blot and immunohistochemistry (IHC) assays were applied for detection of proteins in tissues or cells.

Results

Circ‐SERPINE2 and YWHAZ were upregulated, and miR‐375 was downregulated in GC tissues and cells. Circ‐SERPINE2 and YWHAZ targetedly bound to miR‐375. Circ‐SERPINE2 promoted cell proliferation and cell cycle progress and inhibited cell apoptosis by sponging miR‐375 and regulating YWHAZ expression in vitro. Circ‐SERPINE2 repressed solid tumour growth through enhancing miR‐375 expression and reducing YWHAZ expression in vivo.

Conclusions

Circ‐SERPINE2 is a novel proliferative promoter through the regulation of miR‐375/YWHAZ. Circ‐SERPINE2/miR‐375/YWHAZ axis might provide a novel therapeutic target of GC.

Downregulation of microRNA-204 increases the expression of matrix metallopeptidase 9 in pediatric patients with pulpitis and Helicobacter pylori infection in the stomach

The present study examined the expression of microRNA (miRNA or miR)-204 in pulp tissues, blood and saliva from pediatric patients with pulpitis and an underlying Helicobacter pylori (Hp) infection in the stomach, and the mechanism of the associated regulation by miR-204 was assessed. A total of 26 children with pulpitis who received tooth extraction at the Children's Hospital of Nanjing Medical University (Nanjing, China) between December 2014 and August 2016 were diagnosed with Hp infection in the stomach and included in the present study (HP⁺ group); furthermore, 19 children with pulpitis but without Hp infection in the stomach were enrolled as a control (HP^- group). Pulp tissues, blood (serum) and saliva samples were collected from all subjects. Reverse-transcription quantitative polymerase chain reaction was used to determine the expression of miR-204 and matrix metalloproteinase 9 (MMP9) mRNA. Western blot analysis was performed to determine MMP9 protein expression in pulp tissues, while ELISA was performed to measure the contents of MMP9 in serum and saliva. A dual luciferase reporter assay was used to identify the direct interaction between miR-204 and its target protein. The results indicated that Hp infection in the stomach was associated with an upregulation of MMP9 mRNA and protein in pulp tissues, serum and saliva from children with pulpitis. Furthermore, the levels of miR-204 in pulp tissues, serum and saliva from children with pulpitis and Hp infection in the stomach were significantly reduced. miR-204 was confirmed to regulate the expression of MMP9 by directly binding with the 3'-untranslated region of MMP9 mRNA. The present study demonstrated that MMP9 expression in pulp tissues, blood and saliva from children with pulpitis and Hp infection in the stomach was upregulated, while miR-204 expression was downregulated. miR-204 may affect inflammatory processes and other oral diseases in children with pulpitis and Hp infection via MMP9, and may be a potential marker for the detection of Hp infection in children with pulpitis.

The expression profiling of circulating miR-204, miR-182, and lncRNA H19 as novel potential biomarkers for the progression of peptic ulcer to gastric cancer

Deregulation of noncoding RNAs, microRNAs (miRNAs) and long noncoding RNA (lncRNA), are implicated in the initiation and progression of gastric cancer (GC). This study is a pilot case-control study carried out on 75 subjects, 40 of them were Helicobacter pylori-gastric ulcer patients and 35 were GC patients recruited from the Gastrointestinal Endoscopy Unit in Al-Kasr Al-Aini Hospital, Cairo University in Egypt. Real-time PCR was performed to evaluate the expression level of serum miR-204, miR-182, and lncRNA H19 in patients with peptic ulcer-progressed GC vs nonprogressed peptic ulcer patients. Fibroblast growth factor 18 (FGF-18)/FGF receptor 2 (FGFR2) expression and their downstream immunological and inflammatory signaling markers were assessed and their association with the addressed noncoding RNAs investigated. As regards miR-204 and miR-182, they were significantly increased (12.5 and 2.6 folds, respectively) in GU samples, compared with those of healthy control levels. The elevated levels of these miRNAs were significantly de-escalated in GC samples compared with GU and the fold decrease valued 2.2 fold for miR-204 and 1.8 folds for miR-182. On the other hand, the significant escalation in the level of lnRNA H19 in GU recorded a 16.6 fold increase and further elevation in its levels was evident in GC samples. The herein assessed miRNAs are correlated with disease duration and FGFR2 with miR-182 being significantly correlated with all inflammatory markers, TAC, INF-γ, matrix metallopeptidase 9, and FGF-18. In terms of diagnostic accuracy of assessed miRNAs (stages III to IV), the receiver operating characteristic analysis indicated that serum lncRNA H19 showed the highest diagnostic accuracy (95.5%), specificity (100%), and sensitivity (90.9%), compared with miR-204 and miR-182, which showed the same specificity (60%), sensitivity (72.7%), and diagnostic accuracy (68.8%). Our findings conclude that lnRNA H19, miR-204, and miR-182 may function as novel prospective plasma biomarkers to detect GC and its progression from H. pylori-peptic ulcer, which would be helpful to improve the theranostics of GC.

miR-99b-3p promotes hepatocellular carcinoma metastasis and proliferation by targeting protocadherin 19

Hepatocellular carcinoma (HCC) is one of the most common cancers in the world, with characteristics of high morbidity and mortality. Identifying clinically practical targets and uncovering the potential mechanism for HCC were urgent for us. Though aberrantly expressed miR-99b-3p has been reported in several cancers, the expression and roles of miR-99b-3p in HCC remain uncovered. In the present study, we demonstrated for the first time that miR-99b-3p was overexpressed in HCC by our findings and data from GEO datasets. Statistical analysis revealed that highly expressed miR-99b-3p was closely related to malignant clinicopathological characteristics and poorer prognosis of HCC patients. Furthermore, results from Wound healing assay, Transwell assays, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay and 5-ethynyl-2'-deoxyuridine (EdU) assay revealed that miR-99b-3p played a promoting role in migration, invasion and proliferation of HCC cells. Then, by bioinformatics tools, luciferase reporter gene assay, integrative database analysis, and Pearson correlation analysis and so on, protocadherin 19 (PCDH19) was identified as the target of miR-99b-3p in HCC cells. Furthermore, rescue experiments were conducted to confirm the mediator role of PCDH19 for miR-99b-3p. Collectively, we demonstrate that miR-99b-3p promotes HCC metastasis and proliferation by directly targeting PCDH19. MiR-99b-3p may become a potential therapy target for HCC.

Epigenetic Field Cancerization in Gastric Cancer: microRNAs as Promising Biomarkers

Background: The biological role of microRNAs (miRNAs) in field cancerization is unknown. To investigate the involvement of miRNAs in gastric field cancerization, we evaluated the expression profile of ten miRNAs and their diagnostic value.

Methods: We used three groups of FFPE gastric samples: non-cancer (NC), cancer adjacent (ADJ) and gastric cancer (GC). The expression profiles of hsa-miR-10a, -miR-21, -miR-29c, -miR-135b, -miR-148a, -miR-150, -miR-204, -miR-215, -miR-483 and -miR-664a were investigated using qRT-PCR. The results obtained by qRT-PCR were validated in Small RNA-Seq data from the TCGA database. The search for target genes of the studied miRNAs was performed in the miRTarBase public database and miRTargetLink tool, using experimentally validated interactions. In addition, we also performed the functional analysis of these genes using enrichment in KEGG pathways. The potential as biomarker was evaluated using a receiver operating characteristic (ROC) curve and the derived area under the curve (AUC>0.85) analysis.

Results: The miRNAs hsa-miR-10a, -miR-21, -miR-135b, hsa-miR-148a, -miR-150, -miR-215, -miR-204, -miR-483 and -miR-664a were up-regulated in ADJ and GC compared to NC (P<0.03); and hsa-miR-21 and -miR-135b were up-regulated in GC compared to ADJ (P<0.01). Hsa-miR-148a, -miR-150, -miR-215, -miR-483 and -miR-664a were not differentially expressed between GC and ADJ, suggesting that both share similar changes (P>0.1). The TS-miR hsa-miR-29c was up-regulated in ADJ compared to NC and GC (P<0.01); we did not observe a significant difference in the expression of this miRNA between NC and GC. This feature may be an antitumor mechanism used by cancer-adjacent tissue because this miRNA regulates the BCL-2, CDC42 and DMNT3A oncogenes. The expression level of hsa-miR-204 was associated with Helicobacter pylori infection status (P<0.05). Functional analysis using the genes regulated by the studied miRNAs showed that they are involved in biological pathways and cellular processes that are critical for the establishment of H. pylori infection and for the onset, development and progression of GC. hsa-miR-10a, -miR-21, -miR-135b, -miR-148a, -miR-150, -miR-215, -miR-483 and -miR-664a were able to discriminate NC from other tissues with great accuracy (AUC>0.85).

Conclusion: The studied miRNAs are closely related to field cancerization, regulate genes important for gastric carcinogenesis and can be potentially useful as biomarkers in GC.

Role of abnormal microRNA expression in Helicobacter pylori associated gastric cancer

Epidemiological studies have shown that Helicobacter pylori (HP) infection is a risk factor for gastric cancer (GC). HP infection may induce the release of pro-inflammatory mediators, and abnormally increase the level of reactive oxygen species (ROS), nitric oxide (NO), and cytokines in mucosal epithelial cells of the stomach. However, the specific mechanism underlying the pathogenesis of HP-associated GC is still poorly understood. Recent studies have revealed that abnormal microRNA expression may affect the proliferation, differentiation, and apoptosis of mucosal epithelial cells of the stomach to further influence GC occurrence, development, and metastasis. Herein, we summarize the role of abnormal microRNAs in the regulation of HP-associated GC progression. Abnormal microRNA expression in HP-positive GC may be a biomarker for GC diagnosis, occurrence, and development as well as its targeted treatment and prognosis.

Minor allele of rs1057317 polymorphism in TLR4 is associated with increased risk of Helicobacter pylori -induced gastric cancer

BACKGROUND

Helicobacter pylori (HP) plays a significant role in the carcinogenesis of gastric cancer (GC), the second leading cause of cancer-related death worldwide. The aim of this study was to investigate the effect of rs1057317 polymorphism on the interaction between microRNA-034a (miR-034a) and toll-like receptor 4 (TLR4), and their involvement in the HP-associated GC.

METHODS

Computation analyses, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and luciferase assays were performed to identify potential miRNAs involved in the carcinogenesis of HP-induced GC. Subsequently, the effect of miR-34a and recombinant TNFα-interacting protein α (rTip-α) on the expression of TLR4, interleukin (IL)-6, and tumor necrosis factor α (TNF-α) was measured.

RESULTS

Three hundred and twelve HP-positive GC patients (HP+ GC) and 380 HP-negative GC patients (HP- GC) were enrolled into this study. It was found that, in HP-positive patient, the AA genotype of the rs1057317 polymorphism was closely associated with the risk of GC (95% confidence interval, 1.12 to 2.70; odds ratio, 1.74; P = 0.0129). Furthermore, between the HP+ GC and HP- GC groups, miR-34a was the only miRNA showing a significantly different expression. Subsequently, TLR4 was identified as a target gene of miR-34a. Interestingly, miR-34a evidently reduced the expression of TLR4 3'-untranslated region (3'-UTR) containing the C allele of the rs1057317 polymorphism, but the TLR4 3'-UTR containing the A allele in the rs1057317 was not affected by miR-34a. In addition, the expression of IL-6 and TNF-α was significantly downregulated by miR-34a, but increased by rTip-α. Both miR-34a and rTip-α could enhance the viability of cells, although the effect of rTip-α was stronger.

CONCLUSION

The data of this study suggested that the rs1057317 polymorphism in the miR-34a binding site of TLR4 may predict the risk of HP-induced GC.

Comprehensive Analysis of Aberrantly Expressed ceRNA network in gastric cancer with and without H.pylori infection

Objective: This study mainly focused on revealing ceRNA network in gastric cancer (GC) with Hp infection after comparing with GC without Hp infection and exploring the biological function and prognostic relevance of related molecules.

Methods: The RNA expression profile data of GC patients with or without Hp infection were extracted from TCGA GDC data portal, including 20 GC cases with Hp infection and 168 GC cases without Hp infection. Differentially expressed lncRNAs, miRNAs and mRNAs were unveiled by package edgeR of R, and lncRNA-miRNA-mRNA ceRNA network was constructed by integrating the miRNA target information and the expression data of lncRNAs, miRNAs and mRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of aberrantly expressed mRNAs were performed to identify the related biological functions and pathologic pathways, and protein-protein interaction (PPI) network was constructed by STRING database. The overall survival (OS) of aberrantly expression lncRNAs and miRNAs were analyzed by package survival of R. A total of 30 gastric cancer tissues were used to validate the bioinformatics analysis results by real-time PCR.

Results: Among the 32 differentially expressed miRNAs, 27 differentially expressed lncRNAs and 257 differentially expressed mRNAs were identified by comparing GC patients with and without Hp infection. Totally 10 miRNA, 11 lncRNA, 219 mRNA were included to build ceRNA network. GO and KEGG analysis revealed that differentially expressed mRNAs involved in the ceRNA network were mainly involved in extracellular exosomes, structural molecular activities, proteolysis and P13K-Akt signaling pathways. And PPI analysis obtained six hub genes of NTS, APOC3, OTX2, KRT13, CALCA, GNG4. Survival analysis showed that four lncRNAs (LINC01254, LINC01287, LINC01524, U95743.1) and four miRNAs (miR-302a, miR-302b, miR-1286, miR-378g) were associated with overall survival of GC with Hp infection. The real-time PCR results showed that, the levels of LINCO1254, LINCO1287, LINCO1524, U95743.1 were significantly higher in Hp positive GC patients than Hp negative patients (P=0.02, 0.048, 0.04, 0.036, respectively).

Conclusion: Using TCGA database for data mining, we have successfully constructed a ceRNA regulatory network of GC with Hp infection, consisting of 10 lncRNAs, 11 miRNAs and 219 mRNAs. These findings might provide critical clues for the regulatory role of ceRNA network in the development of GC with Hp infection.

The inhibitive effect of sh-HIF1A-AS2 on the proliferation, invasion, and pathological damage of breast cancer via targeting miR-548c-3p through regulating HIF-1α/VEGF pathway in vitro and vivo

Background

Breast cancer (BC) has been the commonest malignant tumor with a low survival rate among woman. Long non-coding RNA hypoxia-inducible factor-1 alpha antisense RNA-2 (HIF1A-AS2) was correlated with various cancers.

Purpose

The study aimed to investigate the roles and related underlying molecular mechanisms of HIF1A-AS2 in BC.

Material and methods

Target relationships were speculated by Targetscan 7.0 and confirmed by dual luciferase reporter assay. Proteins levels were monitored by RT-qPCR, Western blot and immunohistochemistry assays. CCK-8 assay, SA-β-gal staining and transwell assay were used to detect proliferation, senescence and invasion, respectively. Xenograft nude mice were put into use to evaluate the tumor growth and motility.

Results

The present study exhibited that HIF1A-AS2 and hypoxia-inducible factor-1 alpha (HIF-1α) were upregulated while miR-548c-3p was downregulated in MDA-MB-231, MCF-7, ZR-75-1, and BT-549 BC cell lines. Bioinformatics analysis showed HIF1A-AS2 and HIF-1α were two targets of miR-548c-3p, and the target relationship was further confirmed by dual luciferase reporter assay. Moreover, knockdown of HIF1A-AS2 by shRNA (sh-HIF1A-AS2) markedly elevated miR-548c-3p level, and the enhanced miR-548c-3p noticeably suppressed cell proliferation, invasion, and epithelial–mesenchymal transition, and promoted senescence in vitro. In addition, overexpression of HIF-1α promoted MCF-7 cell invasion. Intriguingly, low expression of HIF1A-AS2 reduced HIF-1α level by upregulating the expression of miR-548c-3p. Furthermore, experiment in xenograft nude mice has indicated that sh-HIF1A-AS2 inhibited tumor growth and motility by targeting miR-548c-3p through regulating HIF-1α/vascular endothelial growth factor (VEGF) pathway in vivo.

Conclusion

The inhibitive effect of HIF-1α/VEGF pathway by sh-HIF1A-AS2 through targeting miR-548c-3p plays crucial regulatory roles in BC. Therefore, designing targeted drugs against HIF1A-AS2 provides a new direction for the treatment of BC.

Mechanisms of Inflammasome Signaling, microRNA Induction and Resolution of Inflammation by Helicobacter pylori

Inflammasome-controlled transcription and subsequent cleavage-mediated activation of mature IL-1β and IL-18 cytokines exemplify a crucial innate immune mechanism to combat intruding pathogens. Helicobacter pylori represents a predominant persistent infection in humans, affecting approximately half of the population worldwide, and is associated with the development of chronic gastritis, peptic ulcer disease, and gastric cancer. Studies in knockout mice have demonstrated that the pro-inflammatory cytokine IL-1β plays a central role in gastric tumorigenesis. Infection by H. pylori was recently reported to stimulate the inflammasome both in cells of the mouse and human immune systems. Using mouse models and in vitro cultured cell systems, the bacterial pathogenicity factors and molecular mechanisms of inflammasome activation have been analyzed. On the one hand, it appears that H. pylori-stimulated IL-1β production is triggered by engagement of the immune receptors TLR2 and NLRP3, and caspase-1. On the other hand, microRNA hsa-miR-223-3p is induced by the bacteria, which controls the expression of NLRP3. This regulating effect by H. pylori on microRNA expression was also described for more than 60 additionally identified microRNAs, indicating a prominent role for inflammatory and other responses. Besides TLR2, TLR9 becomes activated by H. pylori DNA and further TLR10 stimulated by the bacteria induce the secretion of IL-8 and TNF, respectively. Interestingly, TLR-dependent pathways can accelerate both pro- and anti-inflammatory responses during H. pylori infection. Balancing from a pro-inflammation to anti-inflammation phenotype results in a reduction in immune attack, allowing H. pylori to persistently colonize and to survive in the gastric niche. In this chapter, we will pinpoint the role of H. pylori in TLR- and NLRP3 inflammasome-dependent signaling together with the differential functions of pro- and anti-inflammatory cytokines. Moreover, the impact of microRNAs on H. pylori-host interaction will be discussed, and its role in resolution of infection versus chronic infection, as well as in gastric disease development.

MicroRNA-99b promotes Helicobacter pylori-induced autophagyand suppresses carcinogenesis by targeting mTOR

The regulatory mechanism of Helicobacter pylori-induced gastric carcinogenesis remains unclear. Autophagy has previously been identified as an effective method of regulating carcinogenesis. In the present study, microRNA (miR)-99b levels increased in H. pylori-infected gastric cancer tissues and the BGC-823 gastric cancer cell line. Overexpression of miR-99b significantly enhanced autophagy, decreased intracellular bacterial loads and blocked cell proliferation. The effect on autophagy was demonstrated to be triggered by mammalian target of rapamycin inhibition. These results indicate that miR-99b expression serves a key role in preventing H. pylori-associated gastric cancer formation and this may provide potential targets for the future treatment of H. pylori-associated diseases.

MiR-338-5p Promotes Glioma Cell Invasion by Regulating TSHZ3 and MMP2

This study was designed to examine differential expression of miR-338-5p in gliomas and the role of miR-338-5p in glioma cell invasion via its potential target gene TSHZ3 encoding Teashirt zinc finger homobox 3, predicted by bioinformatics, and matrix metallopeptidase 2 (MMP2), the key pro-invasive protease overexpressed in gliomas. Quantitative real-time reverse transcription PCR (qRT-PCR) and Spearman correlation analysis were used to determine differential expressions of miR-338-5p and TSHZ3 in astrocytic gliomas of different grades (n = 35) and glioblastoma cell lines (U87 and U251) in comparison to non-neoplastic brain (NNB) tissues (n = 6). Western blotting was used to determine the protein levels of TSHZ3 and MMP2 in glioblastoma cell lines and Matrigel invasion assay to examine the role of miR-338-5p in cell invasiveness. The results showed that the expression of miR-338-5p, normalized to hsnRNA U6, was significantly higher in grade III and IV gliomas and glioblastoma cell lines compared to that in NNB and grade II gliomas, whereas TSHZ3 expression, normalized to GAPDH, was inversely related to miR-338-5p (R = -0.636, P < 0.01). Luciferase assays showed TSHZ3 to be a target gene of miR-338-5p. In both U87 and U251 cells, miR-338-5p mimics increased MMP2 and invasiveness of the cells. Overexpression of ectopic TSHZ3 suppressed the cell invasiveness and attenuated the pro-invasive effect of miR-338-5p mimics. Overall, our results showed that miR-338-5p has a function in promoting glioma cell invasion by targeting TSHZ3 suppression on MMP2. In conclusion, miR-338-5p is a possible potential biomarker for the diagnosis and target for therapy of high-grade glioma.