Dynamic changes in microRNA expression profiles reflect progression of Barrett's esophagus to esophageal adenocarcinoma

Unraveling Therapeutic Opportunities and the Diagnostic Potential of microRNAs for Human Lung Cancer

Lung cancer is a major public health problem and a leading cause of cancer-related deaths worldwide. Despite advances in treatment options, the five-year survival rate for lung cancer patients remains low, emphasizing the urgent need for innovative diagnostic and therapeutic strategies. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets for lung cancer due to their crucial roles in regulating cell proliferation, differentiation, and apoptosis. For example, miR-34a and miR-150, once delivered to lung cancer via liposomes or nanoparticles, can inhibit tumor growth by downregulating critical cancer promoting genes. Conversely, miR-21 and miR-155, frequently overexpressed in lung cancer, are associated with increased cell proliferation, invasion, and chemotherapy resistance. In this review, we summarize the current knowledge of the roles of miRNAs in lung carcinogenesis, especially those induced by exposure to environmental pollutants, namely, arsenic and benzopyrene, which account for up to 1/10 of lung cancer cases. We then discuss the recent advances in miRNA-based cancer therapeutics and diagnostics. Such information will provide new insights into lung cancer pathogenesis and innovative diagnostic and therapeutic modalities based on miRNAs.

Epigenetic Alterations from Barrett's Esophagus to Esophageal Adenocarcinoma

Barrett's esophagus (BE) is a disease entity that is a sequela of chronic gastroesophageal reflux disease that may result in esophageal adenocarcinoma (EAC) due to columnar epithelial dysplasia. The histological degree of dysplasia is the sole biomarker frequently utilized by clinicians. However, the cost of endoscopy and the fact that the degree of dysplasia does not progress in many patients with BE diminish the effectiveness of histological grading as a perfect biomarker. Multiple or more quantitative biomarkers are required by clinicians since early diagnosis is crucial in esophageal adenocancers, which have a high mortality rate. The presence of epigenetic factors in the early stages of this neoplastic transformation holds promise as a predictive biomarker. In this review, current studies on DNA methylations, histone modifications, and noncoding RNAs (miRNAs) that have been discovered during the progression from BE dysplasia to EAC were collated.

Intestinal metaplasia in progression of Barrett's esophagus to esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has been increasing year by year. The prognosis of EAC is poor, and the 5-year survival rate is less than 20%. Barrett's esophagus (BE) is the only known precancerous lesion of EAC. BE with intestinal metaplasia (IM) has a higher risk of progressing to EAC. Exploring the mechanism of IM and finding targeted therapeutic targets for BE has become an important measure for tumor prevention. Bile acid reflux is considered an important factor in the occurrence of IM and promotes the progression of BE to EAC. However, the molecular regulatory mechanism of bile reflux induced IM and carcinogenesis remains unclear. This article reviews the environment, significance, and cell origin theory of IM, toxic effects of bile reflux, and molecular changes of IM progression to tumor, aiming to improve clinicians' understanding of IM in BE and provide evidence for early intervention of BE and prevention and treatment of EAC.

Kyoto international consensus report on anatomy, pathophysiology and clinical significance of the gastro-oesophageal junction

OBJECTIVE

An international meeting was organised to develop consensus on (1) the landmarks to define the gastro-oesophageal junction (GOJ), (2) the occurrence and pathophysiological significance of the cardiac gland, (3) the definition of the gastro-oesophageal junctional zone (GOJZ) and (4) the causes of inflammation, metaplasia and neoplasia occurring in the GOJZ.

DESIGN

Clinical questions relevant to the afore-mentioned major issues were drafted for which expert panels formulated relevant statements and textural explanations.A Delphi method using an anonymous system was employed to develop the consensus, the level of which was predefined as ≥80% of agreement. Two rounds of voting and amendments were completed before the meeting at which clinical questions and consensus were finalised.

RESULTS

Twenty eight clinical questions and statements were finalised after extensive amendments. Critical consensus was achieved: (1) definition for the GOJ, (2) definition of the GOJZ spanning 1 cm proximal and distal to the GOJ as defined by the end of palisade vessels was accepted based on the anatomical distribution of cardiac type gland, (3) chemical and bacterial (Helicobacter pylori) factors as the primary causes of inflammation, metaplasia and neoplasia occurring in the GOJZ, (4) a new definition of Barrett's oesophagus (BO).

CONCLUSIONS

This international consensus on the new definitions of BO, GOJ and the GOJZ will be instrumental in future studies aiming to resolve many issues on this important anatomic area and hopefully will lead to better classification and management of the diseases surrounding the GOJ.

Barrett's esophagus: The pathomorphological and molecular genetic keystones of neoplastic progression

Barrett's esophagus is a widespread chronically progressing disease of heterogeneous nature. A life threatening complication of this condition is neoplastic transformation, which is often overlooked due to lack of standardized approaches in diagnosis, preventative measures and treatment. In this essay, we aim to stratify existing data to show specific associations between neoplastic transformation and the underlying processes which predate cancerous transition. We discuss pathomorphological, genetic, epigenetic, molecular and immunohistochemical methods related to neoplasia detection on the basis of Barrett's esophagus. Our review sheds light on pathways of such neoplastic progression in the distal esophagus, providing valuable insight into progression assessment, preventative targets and treatment modalities. Our results suggest that molecular, genetic and epigenetic alterations in the esophagus arise earlier than cancerous transformation, meaning the discussed targets can help form preventative strategies in at-risk patient groups.

Identification of miRNAs and genes for predicting Barrett's esophagus progressing to esophageal adenocarcinoma using miRNA-mRNA integrated analysis

Barrett's esophagus (BE) is defined as any metaplastic columnar epithelium in the distal esophagus, which predisposes to esophageal adenocarcinoma (EAC). Yet, the mechanism through which BE develops to EAC still remain unclear. Moreover, the miRNA-mRNA regulatory network in distinguishing BE from EAC still remains poorly understood. To identify differentially expressed miRNAs (DEMs) and genes (DEGs) between EAC and BE from tissue samples, gene expression microarray datasets GSE13898, GSE26886, GSE1420 and miRNA microarray datasets GSE16456, GSE20099 were downloaded from Gene Expression Omnibus (GEO) database. GEO2R was used to screen the DEMs and DEGs. Pathway and functional enrichment analysis were performed by DAVID database. The protein-protein interaction (PPI) network was constructed by STRING and been visualized by Cytoscape software. Finnal, survival analysis was performed basing TCGA database. A total of 21 DEMs were identified. The enriched functions and pathways analysis inclued Epstein-Barr virus infection, herpesvirus infection and TRP channels. GART, TNFSF11, GTSE1, NEK2, ICAM1, PSMD12, CTNNB1, CDH1, PSEN1, IL1B, CTNND1, JAG1, CDH17, ITCH, CALM1 and ITGA6 were considered as the hub-genes. Hsa-miR-143 and hsa-miR-133b were the highest connectivity target gene. JAG1 was predicted as the largest number of target miRNAs. The expression of hsa-miR-181d, hsa-miR-185, hsa-miR-15b, hsa-miR-214 and hsa-miR-496 was significantly different between normal tissue and EAC. CDH1, GART, GTSE1, NEK2 and hsa-miR-496, hsa-miR-214, hsa-miR-15b were found to be correlated with survival.

MiRNA-30e downregulation increases cancer cell proliferation, invasion and tumor growth through targeting RPS6KB1

Human esophagus carcinoma (EC) is one of the most common malignant tumors, especially in Africa and Asia including China. In EC initiation and progression, genetic and epigenetic aberrations have been reported to play a major role, but the underlying molecular mechanisms are largely unknown. In this study, the miR-30e levels were analyzed in human EC tissues and TCGA databases, and the results demonstrated that miR-30e expression in EC tissues was significantly decreased compared to adjacent normal tissues. To further investigate the role of miR-30e in cancer cells, we found that forced expression of miR-30e dramatically inhibited cell proliferation, invasion, tube formation, and colony formation of cancer cells. To determine the underlying mechanism of miR-30e, we found that RPS6KB1 was a direct target of miR-30e by binding to its 3′-UTR, which was verified by luciferase activity assay using reporters with wild-type miR-30e and its seed sequence mutant constructs and Western blotting assay. In vivo experiment showed that miR-30e overexpression significantly inhibited tumor growth and decreased RPS6KB1 expression in xenografts. In EC, high expression of RPS6KB1 in tumor tissues indicated poor prognosis of patients with less survival rate. High levels of RPS6KB1 and low levels of miR-30e closely correlated poor survival of patients with several other types of cancer. These findings show that miR-30e and its target RPS6KB1 are important in cancer development and clinical outcomes, and miR-30e/RPS6KB1 is a potential future therapeutic pathway for EC intervention.

miRNAs as Biomarkers for Diagnosing and Predicting Survival of Head and Neck Squamous Cell Carcinoma Patients

Simple Summary

Head and Neck Squamous Cell Carcinoma (HNSCC) is the sixth most common cancer worldwide. It arises from the epithelium of the upper aerodigestive tract. Increasing evidence suggests that there is a significant role of microRNAs in HNSCC formation and progression. The aim of this study was to explore and compare the expression of HNSCC related miRNAs in tumor vs neighboring healthy tissue of HNSCC patients with tumors located in either the oral cavity, oropharynx, or larynx. Our results demonstrated that expression of these miRNAs was significantly different not only between healthy and tumor tissues, but also among tumor locations. Further analysis indicated that microRNA expression could be used to distinguish between tumor and healthy tissues, and prognose the overall survival of patients.

Abstract

Head and Neck Squamous Cell Carcinoma (HNSCC) is the sixth most common cancer worldwide. These tumors originate from epithelial cells of the upper aerodigestive tract. HNSCC tumors in different regions can have significantly different molecular characteristics. While many microRNAs (miRNAs) have been found to be involved in the regulation of the carcinogenesis and pathogenesis of HNSCC, new HNSCC related miRNAs are still being discovered. The aim of this study was to explore potential miRNA biomarkers that can be used to diagnose HNSCC and prognose survival of HNSCC patients. For this purpose, we chose a panel of 12 miRNAs: miR-146a-5p, miR-449a, miR-126-5p, miR-34a-5p, miR-34b-5p, miR-34c-5p, miR-217-5p, miR-378c, miR-6510-3p, miR-96-5p, miR-149-5p, and miR-133a-5p. Expression of these miRNAs was measured in tumor tissue and neighboring healthy tissue collected from patients diagnosed with HNSCC (n = 79) in either the oral cavity, oropharynx, or larynx. We observed a pattern of differentially expressed miRNAs at each of these cancer locations. Our study showed that some of these miRNAs, separately or in combination, could serve as biomarkers distinguishing between healthy and tumor tissue, and their expression correlated with patients’ overall survival.

The role of SOX family transcription factors in gastric cancer

Gastric cancer (GC) is a leading cause of death worldwide. GC is the third-most common cause of cancer-related death after lung and colorectal cancer. It is also the fifth-most commonly diagnosed cancer. Accumulating evidence has revealed the role of signaling networks in GC progression. Identification of these molecular pathways can provide new insight into therapeutic approaches for GC. Several molecular factors involved in GC can play both onco-suppressor and oncogene roles. Sex-determining region Y (Sry)-box-containing (SOX) family members are transcription factors with a well-known role in cancer. SOX proteins can bind to DNA to regulate cellular pathways via a highly conserved domain known as high mobility group (HMG). In the present review, the roles of SOX proteins in the progression and/or inhibition of GC are discussed. The dual role of SOX proteins as tumor-promoting and tumor-suppressing factors is highlighted. SOX members can affect upstream mediators (microRNAs, long non-coding RNAs and NF-κB) and down-stream mediators (FAK, HIF-1α, CDX2 and PTEN) in GC. The possible role of anti-tumor compounds to target SOX pathway members in GC therapy is described. Moreover, SOX proteins may be used as diagnostic or prognostic biomarkers in GC.

Effect of miR-196a inhibition on esophageal cancer growth in vitro

Esophageal cancer has recent shown a higher incidence but lower 5-year survival rate after normal clinical treatment in China. The aim of this study was to observe whether the inhibition of miR-196a affects esophageal cancer cell growth by modulating the nuclear factor-κB target gene and to detect the possible cooperative therapeutic effects on esophageal cancer by knocking down miR-196a expression combined with the specific inhibitor of nuclear factor-κB target genes. Thus, anti-miR-196a or sotrastaurin, a protein kinase C (PKC) inhibitor, were used to alter PKC expression. We found that miR-196a knockdown or PKC inhibition by sotrastaurin changed PKC expression which then reduced esophageal cancer cell proliferation and downregulated proliferating cell nuclear antigen expression via the classical B-cell receptor-PKC nuclear factor-κB pathway but not the alternative pathway; in addition, miR-196a inhibition can increase the caspase level and induce esophageal cancer cell apoptosis. Our current results provided the evidence that miR-196a was related to the classical nuclear factor-κB pathway, and these new findings proved the potential therapeutic effect of miR-196a in targeted therapy for clinical esophageal cancer patients.

Artificial intelligence technique in detection of early esophageal cancer

Due to the rapid progression and poor prognosis of esophageal cancer (EC), the early detection and diagnosis of early EC are of great value for the prognosis improvement of patients. However, the endoscopic detection of early EC, especially Barrett's dysplasia or squamous epithelial dysplasia, is difficult. Therefore, the requirement for more efficient methods of detection and characterization of early EC has led to intensive research in the field of artificial intelligence (AI). Deep learning (DL) has brought about breakthroughs in processing images, videos, and other aspects, whereas convolutional neural networks (CNNs) have shone lights on detection of endoscopic images and videos. Many studies on CNNs in endoscopic analysis of early EC demonstrate excellent performance including sensitivity and specificity and progress gradually from in vitro image analysis for classification to real-time detection of early esophageal neoplasia. When AI technique comes to the pathological diagnosis, borderline lesions that are difficult to determine may become easier than before. In gene diagnosis, due to the lack of tissue specificity of gene diagnostic markers, they can only be used as supplementary measures at present. In predicting the risk of cancer, there is still a lack of prospective clinical research to confirm the accuracy of the risk stratification model.

The lncRNA PVT1 promotes invasive growth of lung adenocarcinoma cells by targeting miR-378c to regulate SLC2A1 expression

As an oncogene, plasmacytoma variant translocation 1 (PVT1) has been found to be highly expressed in several cancers. However, its specific role in lung adenocarcinoma (ADC) has not been fully elucidated. In this study, the expression of PVT1, miR-378c, and solute carrier family 2 member 1 (SLC2A1) was determined by quantitative real-time PCR and western blot. Dual-luciferase reporter assay was used to explore the relationship between PVT1 and miR-378c, as well as miR-378c and SLC2A1. The effects of PVT1 on the lung ADC cells proliferation, invasion, and migration were detected using MTT, wound-healing, and transwell assays. The results revealed that PVT1 was highly expressed in lung ADC cells, and the overexpression of PVT1 promoted the proliferation, migration, and invasion of lung ADC cells. In lung ADC cells, PVT1 negatively regulated miR-378c expression, and miR-378c negatively regulated SLC2A1 expression through binding to its 3'-untranslated coding regions. Knocking down of PVT1 inhibited the abilities of cell proliferation, migration, and invasion, while miR-378c inhibitor or SLC2A1 Vector diminished the effect. Together, silencing PVT1 downregulated SLC2A1 expression via targeting miR-378c, and then repressed lung ADC cells growth, migration, and invasion.

MicroRNAs: potential biomarkers for diagnosis and prognosis of different cancers

A thorough understanding of the tumor environment and underlying genetic factors helps in the better formulation of cancer management strategies. Availability of efficient diagnostic and prognostic biomarkers facilitates early detection and progression of the disease. MicroRNAs affect different biological processes participating in tumorigenesis through regulation of their target genes. An expanding list of unique RNAs and understanding of their regulatory role has opened up a new field in cancer research. Based on a comprehensive literature search, we identified 728 miRNAs dysregulated in sixteen cancer types namely bladder cancer (BC), breast cancer (BrC), cervical cancer (CC), colorectal cancer (CRC), esophageal cancer (EC), endometrial cancer (EnC), gastric cancer (GC), hepatocellular cancer (HCC), head and neck squamous cell cancer (HNSCC), lung cancer (LC), ovarian cancer (OC), pancreatic cancer (PC), prostate cancer (PrC), renal cell cancer (RCC), skin cancer (SC), and thyroid cancer (TC). Expression of 43 miRNAs was either upregulated or downregulated in six or more of these cancers. Finally, seven miRNAs namely mir-18a, mir-21, mir-143/145, mir-210, mir-218, mir-221, showing maximum dysregulation, either up- or down-regulation in the majority of cancers, were selected for a detailed presentation of their expression and evaluation of their potential as biomarkers in the diagnosis and prognosis of different cancers.

miR-28-5p targets MTSS1 to regulate cell proliferation and apoptosis in esophageal cancer

Esophageal cancer (EC) is one of the most common aggressive malignant diseases worldwide. miR-28-5p plays important regulatory roles in many cancers including human EC. However, the molecular mechanism and potential role of miR-28-5p in EC remain uncertain. In this study, qRT-PCR and western blot analysis revealed that miR-28-5p expression was up-regulated and metastasis suppressor-1 (MTSS1) was down-regulated in EC tissues relative to matched para-cancer tissues. Cell counting kit-8 (CCK-8) assay demonstrated that miR-28-5p mimics increased cell viability, and miR-28-5p inhibitor decreased it. Flow cytometry (FCM) assay indicated that miR-28-5p mimics promoted cell cycle entry, while miR-28-5p inhibitor reduced it and induced cell apoptosis. Moreover, miR-28-5p mimics up-regulated the expressions of cyclin A, cyclin dependent kinase 2 (CDK2), cyclin D1, and cyclin E but down-regulated the expressions of cleaved caspase-3 and cleaved caspase-9, which was abolished by miR-28-5p inhibitor. Furthermore, luciferase reporter assay verified that miR-28-5p directly targeted MTSS1 3'UTR and down-regulated its expression. MTSS1 overexpression in TE-1 cells inhibited cell proliferation and promoted apoptosis induced by miR-28-5p mimics, whereas silencing of MTSS1 reversed cell progression induced by miR-28-5p inhibitor. We also demonstrated that miR-28-5p could promote esophageal tumor formation in vivo. Hematoxylin-eosin staining, immunohistochemistry, and TUNEL assays confirmed that miR-28-5p antagomir inhibited cell growth and accelerated apoptosis. Our results suggest that miR-28-5p may induce cell proliferation and suppress apoptosis to promote EC tumor formation via decreasing MTSS1 expression. Thus, miR-28-5p may be a potential target for human EC therapy.

Circulating exosomal miRNAs as potential biomarkers for Barrett's esophagus and esophageal adenocarcinoma

Exosomes, a class of extracellular vesicles, are small membrane-bound vesicles derived from almost all cell types that can play important roles in intercellular communication. Exosomes contain proteins, lipids, and nucleic acids that are obtained from the parental cells and participate in various pathophysiological processes, including cell growth, migration, inflammation, immune regulation, and tumor pathogenesis. Moreover, exosomes might be applied in clinical settings, such as diagnosis, treatment, and outcome prediction of diseases, including various cancers. The incidence rates of Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) have increased in recent decades, and studies have proposed specific factors that may contribute to the development and progression of these diseases. However, how exosomes play a role in this pathological process needs to be clarified. Studies have identified candidate microRNAs (miRNAs) that might be related to BE/EAC. Further studies are needed to ascertain whether circulating exosomal miRNAs are altered before or after disease onset, which could also help understand the pathophysiology of and find potential targets for prevention, diagnosis, and therapy in BE/EAC. This review summarizes recent findings on the features of circulating exosomal miRNAs in BE/EAC, which could be valuable for the early diagnosis, therapeutic approaches, and outcome prediction of BE/EAC.

microRNA-mRNA network model in patients with achalasia

BACKGROUND

Achalasia is a rare idiopathic disease with a complex etio-pathogenesis still unknown. This study aimed to identify microRNA (miRNA)-mRNA regulatory networks underlying achalasia.

METHODS

The investigation was performed in tissue specimens from 11 patients and five controls using the microarray technology followed by an integrated bioinformatics analysis.

KEY RESULTS

One hundred and six miRNAs were significantly up-regulated and 64 were down-regulated in achalasia patients. The expression of the most 10 differential expressed miRNAs (miR-122-5p, miR-133a-3p, miR-504-5p, miR-187-3p, miR-133b, miR-200c-3p, miR-375, miR-200b-5p, miR-200b-3p, and miR203a) was confirmed by droplet digital PCR in an independent cohort. The interactions between the significant miRNAs and their targets uncovered 14 miRNA-mRNA interacting pairs with experimentally predicted genes (ie, FN1, ROCK2, DPYSL2), and 35 pairs with not experimentally target genes (ie, SULF1, MRVI1, PRKG1); all genes were involved in immune cell trafficking, skeletal and muscular system development, nervous system development macro-processes.

CONCLUSION & INFERENCES

The mRNA-miRNA regulatory networks described in this study provide new insights in the genetic background of the disease, suggesting further investigations in novel pathogenic mechanisms.

Expression of the microRNA-200 Family, microRNA-205, and Markers of Epithelial-Mesenchymal Transition as Predictors for Endoscopic Submucosal Dissection over Esophagectomy in Esophageal Adenocarcinoma: A Single-Center Experience

Endoscopic submucosal dissection (ESD) is an effective treatment of early esophageal adenocarcinomas (EACs). The decision of ESD over esophagectomy is based on clinical evaluation of tumor depth and invasion. On a molecular level, tumor invasion is strongly associated with epithelial-to-mesenchymal transition (EMT). Here, we investigated whether localized ESD-resected and surgically resected EAC samples displayed different expression profiles of EMT protein and microRNA markers and whether these different expression profiles were able to retrospectively discriminate localized and surgically resected samples. By doing this, we aimed to evaluate whether preoperative measurement of EMT marker expression might support the decision regarding ESD over surgery. The results showed that ESD-resected samples displayed an epithelial expression profile, i.e., high expression of epithelial protein markers, whereas surgically resected samples displayed high expression of mesenchymal markers. In addition, the anti-EMT microRNA-205 was significantly more expressed in ESD-resected samples, whereas we found no significant differences in the expression levels of microRNA-200 family members. Furthermore, in our retrospective approach, we have demonstrated that measurement of selected EMT markers and microRNA-205 has significant discrimination power to distinguish ESD-resected and surgically resected samples. We suggest that the assessment of EMT status of EAC samples on a molecular level may support clinical evaluation regarding the applicability of ESD.

Bioinformatic analyses of microRNA-targeted genes and microarray-identified genes correlated with Barrett's esophagus

Barrett's esophagus (BE) is defined as a metaplasia condition in the distal esophagus, in which the native squamous epithelium lining is replaced by a columnar epithelium with or without intestinal metaplasia. It is commonly accepted that BE is a precancerous lesion for esophageal adenocarcinoma. The aim of this study was to investigate the aberrant microRNAs (miRNAs) and differentially expressed genes (DEGs) associated with BE based on online microarray datasets. One miRNA and five gene expression profiling datasets were retrieved from the Gene Expression Omnibus Database. Aberrant microRNAs and DEGs were obtained using R/Bioconductor statistical analysis language and software. 23 dysregulated miRNAs and 632 DEGs demonstrating consistent expression tendencies in the five gene microarrays were identified in BE. Moreover, 1962 target genes of aberrant miRNAs were predicted using three bioinformatic tools, namely TargetScan, RNA22-HSA and miRDB. Ultimately, 93 target DEGs were obtained, after which functional annotation was performed on DAVID Bioinformatics Resources. Among Gene Ontology (GO) biological processes, digestive tract development and epithelial cell differentiation have demonstrated significant associations with BE pathogenesis. In addition, analysis of the KEGG pathways has revealed associations with cancer. To enable further study, one miRNA-target DEGs regulatory network was constructed using Cytoscape. 6 target DEGs demonstrated higher-degree distributions in the network, and ROC analysis indicated that FNDC3B may be the best potential biomarker for BE diagnosis. The data presented herein may provide new perspectives for exploring BE pathogenesis and may offer hits with regard to potential biomarkers in BE diagnosis, prediction and therapeutic evaluation.

SOX2 interferes with the function of CDX2 in bile acid-induced gastric intestinal metaplasia

Background

Intestinal metaplasia (IM) is a premalignant lesion associated with gastric cancer. Both animal and clinical studies have revealed that bile acid reflux and subsequent chronic inflammation are key causal factors of IM. Previous studies indicated that SOX2, the key transcription factor in gastric differentiation, was downregulated during IM development while CDX2, the pivotal intestine-specific transcription factor was upregulated significantly. However, it remains unclear whether the downregulation of SOX2 promotes gastric IM emergence or is merely a concomitant phenomenon. In addition, the underlying mechanisms of SOX2 downregulation during IM development are unclear.

Methods

Gastric cell lines were treated with deoxycholic acid (DCA) in a dose-dependent manner. The expression of CDX2 and miR-21 in gastric tissue microarray were detected by immunohistochemistry and in situ hybridization. Coimmunoprecipitation and immunofluorescence were performed to ascertain the interaction of SOX2 and CDX2. Luciferase reporter assays were used to detect the transcriptional activity of CDX2, and confirm miR-21 binding to SOX2 3′-UTR. The protein level of SOX2, CDX2 and downstream IM-specific genes were investigated using western blotting. mRNA level of miR-21, SOX2, CDX2 and downstream IM-specific genes were detected by qRT-PCR.

Results

Bile acid treatment could suppress SOX2 expression and simultaneously induce expression of CDX2 in gastric cell lines. Furthermore, we demonstrated that SOX2 overexpression could significantly inhibit bile acid- and exogenous CDX2-induced IM-specific gene expression, including KLF4, cadherin 17 and HNF4α expression. In contrast, SOX2 knockdown had the opposite effect. A dual-luciferase reporter assay demonstrated that SOX2 overexpression could significantly suppress CDX2 transcriptional activity in HEK293T cells. CDX2 and SOX2 could form protein complexes in the nucleus. In addition, bile acid induced the expression of miR-21. The inhibition of SOX2 in bile acid-treated gastric cell lines was rescued by miR-21 knockdown.

Conclusions

These findings suggested that SOX2 can interfere with the transcriptional activity of CDX2 in bile acid-induced IM and that miR-21 might play a key role in this process, which shed new lights in the prevention of gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0739-8) contains supplementary material, which is available to authorized users.

MicroRNA Expression Profiles in Gastric Carcinogenesis

Intestinal-type gastric carcinoma exhibits a multistep carcinogenic sequence from adenoma to carcinoma with a gradual increase in genomic alterations. But the roles of microRNAs (miRNA) in this multistage cascade are not fully explored. To identify differentially expressed miRNA (DEM) during early gastric carcinogenesis, we performed miRNA microarray profiling with 24 gastric cancers and precursor lesions (7 early gastric cancer [EGC], 3 adenomas with high-grade dysplasia, 4 adenomas with low-grade dysplasia, and 10 adjacent normal tissues). Alterations in the expression of 132 miRNA were detected; these were categorized into three groups based on their expression patterns. Of these, 42 miRNAs were aberrantly expressed in EGC. Five miRNA (miR-26a, miR-375, miR-574-3p, miR-145, and miR-15b) showed decreased expression since adenoma. Expression of two miRNA, miR-200C and miR-29a, was down-regulated in EGCs compared to normal mucosa or adenomas. Six miRNA (miR-601, miR-107, miR-18a, miR-370, miR-300, and miR-96) showed increased expression in gastric cancer compared to normal or adenoma samples. Five representative miRNAs were further validated with RT-qPCR in independent 77 samples. Taken together, these results suggest that the dysregulated miRNA show alterations at the early stages of gastric tumorigenesis and may be used as a candidate biomarker.

Global microarray profiling identified hsa_circ_0064428 as a potential immune-associated prognosis biomarker for hepatocellular carcinoma

BACKGROUND

Increasing evidence has shown that circular RNAs (circRNAs) are involved tumourigenesis and metastasis of hepatocellular carcinoma (HCC); however, progression about its function in HCC is relatively slow. Here, we aimed to investigate whether plasma circRNAs could reflect the tumour-infiltrating lymphocytes (TILs) in HCC tumour tissues and serve as prognosis biomarker for HCC.

METHODS

Tissue samples of patients with HCC were subjected to immunohistochemistry staining against CD8 to examine the TILs. Then, we investigated the expression profile of circRNAs by microarray between plasma of patients with HCC with high TILs and low TILs, and the differentially expressed circRNAs were validated with qRT-PCR. Statistical analysis was performed with SPSS software and GraphPad Prism.

RESULTS

We have demonstrated that patients with HCC with high TILs exhibit a significant better overall survival, suggesting clinical outcome could be predicted by TILs. Global circRNA microarray between plasma of patients with HCC with high TILs and low TILs successfully identified six differentially expressed novel circRNAs. Among them, the expression of hsa_circ_0064428 was significantly reduced in patients with HCC with high TILs but increased in patients with low TILs. Moreover, hsa_circ_0064428 was negatively correlated with patient's survival, tumour size and metastasis.

CONCLUSION

These findings together imply that hsa_circ_0064428 could be considered as a potential HCC prognosis biomarker. Future in-depth research is required to further illustrate the involvement of hsa_circ_0064428 in HCC tumourigenesis and metastasis.

A myriad of roles of miR-25 in health and disease

Small non-coding RNAs including microRNAs (miRNAs) have been recently recognized as important regulators of gene expression. MicroRNAs play myriads of roles in physiological processes as well as in the pathogenesis of a number of diseases by translational repression or mRNA destabilization of numerous target genes. The miR-106b-25 cluster is highly conserved in vertebrates and consists of three members including miR-106b, miR-93 and miR-25. MiR-106b and miR-93 share the same seed sequences; however, miR-25 has only a similar seed sequence resulting in different predicted target mRNAs. In this review, we specifically focus on the role of miR-25 in healthy and diseased conditions. Many of miR-25 target mRNAs are involved in biological processes such as cell proliferation, differentiation, and migration, apoptosis, oxidative stress, inflammation, calcium handling, etc. Therefore, it is no surprise that miR-25 has been reported as a key regulator of common cancerous and non-cancerous diseases. MiR-25 plays an important role in the pathogenesis of acute myocardial infarction, left ventricular hypertrophy, heart failure, diabetes mellitus, diabetic nephropathy, tubulointerstitial nephropathy, asthma bronchiale, cerebral ischemia/reperfusion injury, neurodegenerative diseases, schizophrenia, multiple sclerosis, etc. MiR-25 is also a well-described oncogenic miRNA playing a crucial role in the development of many tumor types including brain tumors, lung, breast, ovarian, prostate, thyroid, oesophageal, gastric, colorectal, hepatocellular cancers, etc. In this review, our aim is to discuss the translational therapeutic role of miR-25 in common diseased conditions based on relevant basic research and clinical studies.

Identification of molecular targets for esophageal carcinoma diagnosis using miRNA-seq and RNA-seq data from The Cancer Genome Atlas: a study of 187 cases

Esophageal carcinoma (ESCA) is one of the most common malignancies worldwide, and its pathogenesis is complex. In this study, we identified differentially expressed miRNAs (DEMs) and genes (DEGs) of ESCA from The Cancer Genome Atlas (TCGA) database. The diagnostic values of DEMs were determined by receiver operating characteristic (ROC) analyses and validated based on data from Gene Expression Omnibus (GEO). The top five DEMs with the best diagnostic values were selected, and their potential targets were predicted by various in silico methods. These target genes were then identified among the DEGs from TCGA. Furthermore, the overlapping genes were subjected to protein-protein interaction (PPI) analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. The miRNA-transcription factor (TF) regulatory relations were determined using CircuitsDB and TransmiR. Finally, the regulatory networks of miRNA-TF and miRNA-gene were constructed and analyzed. A total of 136 DEMs and 3541 DEGs were identified in ESCA. The top five DEMs with the highest area under the receiver operating characteristic curve (AUC) values were miRNA-93 (0.953), miRNA-21 (0.928), miRNA-4746 (0.915), miRNA-196a-1 (0.906) and miRNA-196a-2 (0.906). The combined AUC of these five DEMs was 0.985. The KEGG analysis with 349 overlapping genes showed that the calcium signaling pathway and the neuroactive ligand-receptor interaction were the most relevant pathways. The regulatory networks of miRNA-TF and miRNA-gene, including 38 miRNA-TF and 560 miRNA-gene pairs, were successfully established. Our findings may provide new insights into the molecular mechanisms of ESCA pathogenesis. Future research will aim to explore the role of novel miRNAs in the pathogenesis and improve the early diagnosis of ESCA.

Analysis of tissue and circulating microRNA expression during metaplastic transformation of the esophagus

Genetic changes involved in the metaplastic progression from squamous esophageal mucosa toward Barrett's metaplasia and adenocarcinoma are almost unknown. Several evidences suggest that some miRNAs are differentially expressed in Barrett's esophagus (BE) and esophageal adenocarcinoma. Among these, miR-143, miR-145, miR-194, miR-203, miR-205, miR-215 appear to have a key role in metaplasia and neoplastic progression. The aim of this study was to analyze deregulated miRNAs in serum and esophageal mucosal tissue biopsies to identify new biomarkers that could be associated with different stages of esophageal disease. Esophageal mucosal tissue biopsies and blood samples were collected and analyzed for BE diagnosis. Quantitative Real-time PCR was used to compare miRNA expression levels in serum and 60 disease/normal-paired tissues from 30 patients diagnosed with esophagitis, columnar-lined oesophagus (CLO) or BE. MiRNA expression analysis showed that miR-143, miR-145, miR-194 and miR-215 levels were significantly higher, while miR-203 and miR-205 were lower in BE tissues compared with their corresponding normal tissues. Esophageal mucosa analysis of patients with CLO and esophagitis showed that these miRNAs were similarly deregulated but to a lesser extent keeping the same trend and CLO appeared as intermediate step between esophagitis and BE. Analysis on circulating miRNA levels confirmed that miR-194 and miR-215 were significantly upregulated in both BE and CLO compared to esophagitis, while miR-143 was significantly upregulated only in the Barrett group. These findings suggest that miRNAs may be involved in neoplastic/metaplastic progression and miRNA analysis might be useful for progression risk prediction as well as for monitoring of BE/CLO patients.

microRNA involvement in the onset and progression of Barrett's esophagus: a systematic review

Esophageal adenocarcinoma (EAC) is a highly aggressive malignancy that develops from Barrett's esophagus (BE), an intestinal metaplasia of the distal esophagus. microRNAs (miRNAs), short non-coding regulatory RNAs, are frequently dysregulated in BE and are thought to play key roles in the onset of BE and its progression to EAC. miRNAs thus have potential diagnostic and prognostic value and are increasingly being used as cancer biomarkers. This review summarizes the current literature related to miRNAs that are dysregulated in BE within the context of Hedgehog, Notch, MAPK, NF kappa-B, Wnt and epithelial-mesenchymal transition (EMT) signaling which are thought to drive BE onset and progression. This comprehensive analysis of miRNAs and their associated signaling in the regulation of BE provides an overview of vital discoveries in this field and highlights gaps in our understanding of BE pathophysiology that warrant further investigation.

Omeprazole Inhibits Cell Proliferation and Induces G0/G1 Cell Cycle Arrest through Up-regulating miR-203a-3p Expression in Barrett's Esophagus Cells

Existing data suggest that proton pump inhibitors (PPIs), particularly omeprazole, have significant anti-tumor action in monotherapy and or combination chemotherapy. Hedgehog (Hh) signaling pathway represents a leading candidate as a molecular mediator of Barrett's esophagus (BE). Studies have indicated reduced miRNAs in BE progression, however, little is known about the latent anti-neoplasm effects of miRNAs in BE cells. Here, we investigated whether omeprazole could inhibit BE progression by regulating Hh pathway and explored the promising Hh-targeted miRNAs in BE cells. We conducted qRT-PCR and immunoblotting assay to evaluate the effects of omeprazole on the expression of Hh signaling components and miR-203a-3p in CP-A and CP-B cells. The promising target genes of miR-203a-3p were predicted by bioinformatics methods, and verified by luciferase assays and qRT-PCR. The effects of omeprazole on BE cell proliferation and cell cycle distribution were determined. The overexpression or silencing of miR-203a-3p was performed to test its anti-proliferative effects. Finally, rescue experiments that miR-203a-3p inhibitor alleviated the effects of omeprazole on decreasing the levels of Gli1 mRNA, protein and luciferase were performed. Mechanistic studies showed that omeprazole could inhibit the expression of Gli1 and the nuclear localization of Gli1. Moreover, we determined that omeprazole could selectively up-regulated the expression of miR-203a-3p, and Gli1 was a bona fide target of miR-203a-3p. miR-203a-3p inhibitor alleviated the suppressing effects of omeprazole on Gli1 luciferase activity, mRNA and protein level. The functional assay suggested that omeprazole could dose-dependently inhibit BE cell growth and induce cell cycle arrest in G0/G1 phase. Additionally, overexpression and silencing of miR-203a-3p in BE cells disrupted cell cycle progress, resulting in suppressing and accelerating cell proliferation, respectively. Taken together, these data provide a novel mechanism of potentially anti-neoplastic effects for omeprazole through modulation of miR-203a-3p expression and thus suppressing Hh/Gli1 signaling in BE cells.

Characteristic miRNA expression signature and random forest survival analysis identify potential cancer-driving miRNAs in a broad range of head and neck squamous cell carcinoma subtypes

AIM

To characterize the miRNA expression profile in head and neck squamous cell carcinoma (HNSSC) accounting for a broad range of cancer subtypes and consequently identify an optimal miRNA signature with prognostic value.

BACKGROUND

HNSCC is consistently among the most common cancers worldwide. Its mortality rate is about 50% because of the characteristic aggressive behavior of these cancers and the prevalent late diagnosis. The heterogeneity of the disease has hampered the development of robust prognostic tools with broad clinical utility.

MATERIALS AND METHODS

The Cancer Genome Atlas HNSC dataset was used to analyze level 3 miRNA-Seq data from 497 HNSCC patients. Differential expression (DE) analysis was implemented using the limma package and multivariate linear model that adjusted for the confounding effects of age at diagnosis, gender, race, alcohol history, anatomic neoplasm subdivision, pathologic stage, T and N stages, and vital status. Random forest (RF) for survival analysis was implemented using the randomForestSRC package.

RESULTS

A characteristic DE miRNA signature of HNSCC, comprised of 11 upregulated (i.e., miR-196b-5p, miR-1269a, miR-196a-5p, miR-4652-3p, miR-210-3p, miR-1293, miR-615-3p, miR-503-5p, miR-455-3p, miR-205-5p, and miR-21-5p) and 9 downregulated (miR-376c-3p, miR-378c, miR-29c-3p, miR-101-3p, miR-195-5p, miR-299-5p, miR-139-5p, miR-6510-3p, miR-375) miRNAs was identified. An optimal RF survival model was built from seven variables including age at diagnosis, miR-378c, miR-6510-3p, stage N, pathologic stage, gender, and race (listed in order of variable importance).

CONCLUSIONS

The joint differential miRNA expression and survival analysis controlling for multiple confounding covariates implemented in this study allowed for the identification of a previously undetected prognostic miRNA signature characteristic of a broad range of HNSCC.

Identification of key pathways and genes in Barrett's esophagus using integrated bioinformatics methods

Barrett's esophagus (BE) is a premalignant lesion of esophageal adenocarcinoma. The aim of the present study was to investigate the possible mechanisms and biomarkers of BE. To identify the differentially expressed microRNAs (DEmiRNAs) and genes (DEGs) in BE, the miRNA expression profile GSE20099 and the gene expression profiles GSE26886, GSE13083 and GSE34619 were obtained from the Gene Expression Omnibus (GEO) database. DEGs and DEmiRNAs were screened for using the GEO2R tool. Using DAVID, functional and pathway enrichment analysis was performed to explore the biological function of identified DEGs. The protein-protein interaction (PPI) network was detected using STRING and constructed by Cytoscape software. Furthermore, targets of identified DEmiRNAs were predicted by the miRecords database, then integrated with the identified DEGs to obtain key genes involved in BE. In total, 311 DEGs were identified. These genes were significantly enriched in the pancreatic secretion, metabolic pathways and cytochrome P450 drug metabolism pathways. In the PPI network, 16 hub genes, including keratin 16, cystic fibrosis transmembrane conductance regulator, involucrin, protein kinase C α and cadherin 17 were identified. Following integration of the predicted target genes of DEmiRNAs with DEGs, three key BE genes were identified: PRKCA, CDH17 and epiregulin. In conclusion, a comprehensive bioinformatics analysis of identified DEGs and DEmiRNAs was performed to elucidate potential pathways and biomarkers involved in the development of BE.

Detection of genetic alterations in cfDNA as a possible strategy to monitor the neoplastic progression of Barrett's esophagus

Barrett's esophagus (BE) is associated with an increased risk of developing esophageal adenocarcinoma. Despite the low absolute risk of neoplastic progression of BE, probability increases with the diagnosis of dysplasia. For this reason, BE patients undergo an endoscopy-based surveillance that is, however, burdensome for patients, subject to inter-observer subjectivity, and expensive for national health systems. Thus, less invasive and low-cost diagnostic tools are needed. This study is aimed at finding a simple and reliable method to detect in the circulating cell-free DNA (cfDNA) of BE patients evidence of the molecular instability that accompanies BE carcinogenesis. We chose the loss of heterozygosity analysis because chromosomal region gains or losses have been described in BE and esophageal adenocarcinoma. Furthermore, this analysis does not require an a priori knowledge of tumor specific mutations and/or rearrangements. Previous data showed a good consistency between tissue and cfDNA alterations. Here, we report that, in the cfDNA of dysplastic BE patients, the frequency of genetic alterations is statistically higher than that of metaplastic BE patients (P = 0.005). Interestingly, after endoscopic treatment, the alteration frequency dropped, suggesting that cfDNA can also be used to monitor curative effects. Among the used markers, those that map nearby TP53 gene were the most discriminant between metaplastic and dysplastic BE. Furthermore, longitudinal follow-up cases showed that genetic alterations can be found in cfDNA before the appearance of a detectable lesion. Altogether, our data suggest that the use of liquid biopsy could become a minimally invasive diagnostic tool to implement BE patient monitoring.

miR-194 inhibits the proliferation, invasion, migration, and enhances the chemosensitivity of non-small cell lung cancer cells by targeting forkhead box A1 protein

Recent studies have implied that miRNAs may play a crucial role in tumor progression and may be involved in the modulation of some drug resistance in cancer cells. Earlier studies have demonstrated that miR-194 was involved in tumor metastasis and drug resistance in non-small cell lung cancer (NSCLC), whereas their expression and roles on NSCLC still need further elucidation. In the current study, we found that miR-194 is decreased in NSCLC samples compared with adjacent non-cancerous lung samples, and low expression of miR-194 predicts poor patient survival. Both in vitro and in vivo experiments showed that ectopic stable expression miR-194 suppressed proliferation, migration, invasion and metastasis and induced apoptosis in NSCLC cells and that this suppression could be reversed by reintroducing forkhead box A1 (FOXA1), a functional target of miR-194. In addition, miR-194 was downregulated in in cisplatin-resisted human NSCLC cell line-A549/DDP and overexpression of miR-194 increases cisplatin sensitivity. These findings suggested that miR-194 inhibits proliferation and metastasis and reverses cisplatin-resistance of NSCLC cells and may be useful as a new potential therapeutic target for NSCLC.

Biological implications and clinical value of mir-210 in gastrointestinal cancer

Hypoxia, a common feature of tumor microenvironment, is known to accelerate tumor development and growth by promoting the formation of a neoplastic environment. Recent studies have provided a wealth of evidence that miRNAs are significant members of the adaptive response to low oxygen in tumors. miR-210 is one of the hypoxia-induced miRNAs, which has been reported extensively in cancer researches. However, there is no systematic discussion about the role of miR-210 in gastrointestinal cancer. We conducted a literature research in database including PubMed, Elsevier Science Direct and Medline before 16 September 2016, in order to collect articles of miR-210 in gastrointestinal cancer. Areas covered: In the present review, we mainly discuss the following aspects: hypoxia-induced dysregulation of miR-210, the expression of miR-210 and tumorigenesis, the resultant changes of miR-210 targets and its roles in different types of gastrointestinal cancer progression, the diagnostic, therapeutic and prognostic value of miR-210 in gastrointestinal cancer. Expert commentary: Numerous researches have demonstrated the values of miR-210 in cancer diagnosis, prognosis and targeted therapies, especially in gastrointestinal cancers. However, there are also some existing problems and challenges in translating the new research findings into clinical utility. Further investigations and studies are still urgently required.

Dietary Phytochemicals and Cancer Chemoprevention: A Perspective on Oxidative Stress, Inflammation, and Epigenetics

Oxidative stress occurs when cellular reactive oxygen species levels exceed the self-antioxidant capacity of the body. Oxidative stress induces many pathological changes, including inflammation and cancer. Chronic inflammation is believed to be strongly associated with the major stages of carcinogenesis. The nuclear factor erythroid 2-related factor 2 (Nrf2) pathway plays a crucial role in regulating oxidative stress and inflammation by manipulating key antioxidant and detoxification enzyme genes via the antioxidant response element. Many dietary phytochemicals with cancer chemopreventive properties, such as polyphenols, isothiocyanates, and triterpenoids, exert antioxidant and anti-inflammatory functions by activating the Nrf2 pathway. Furthermore, epigenetic changes, including DNA methylation, histone post-translational modifications, and miRNA-mediated post-transcriptional alterations, also lead to various carcinogenesis processes by suppressing cancer repressor gene transcription. Using epigenetic research tools, including next-generation sequencing technologies, many dietary phytochemicals are shown to modify and reverse aberrant epigenetic/epigenome changes, potentially leading to cancer prevention/treatment. Thus, the beneficial effects of dietary phytochemicals on cancer development warrant further investigation to provide additional impetus for clinical translational studies.

The role of microRNA-196a in tumorigenesis, tumor progression, and prognosis

MicroRNAs are a large group of non-coding RNAs that have emerged as regulators of various biological processes, especially carcinogenesis and cancer progression. Recent evidence has shown that microRNA-196a (miR-196a) is upregulated in most types of tumors and involved in multiple biological processes via translational inhibition and mRNA cleavage, such as cell proliferation, migration, and invasion, mostly functioning as an oncogene. Dysregulation of miR-196a promotes oncogenesis and tumor progression. In this review, we summarize the upstream regulators, target genes, signaling pathways, and single nucleotide polymorphisms of miR-196a, which collectively affect cell proliferation, migration, and invasion. In addition, we review the clinical outcomes and significance of miR-196a. miR-196a may serve as a novel biomarker or target for diagnosis, prognosis, and therapy in several human cancers.

miR-203 Expression in Exfoliated Cells of Tongue Coating Represents a Sensitive and Specific Biomarker of Gastroesophageal Reflux Disease

Background and Aim. MicroRNAs (miRNAs) have been implicated in the pathophysiology of numerous human diseases including gastroesophageal reflux disease (GERD). The objective of this study was to investigate the miRNA expression of exfoliated cells of the tongue in patients with GERD versus healthy controls (Ctrls). Methods. Using quantitative reverse-transcription PCR (qRT-PCR), expression levels of six candidate miRNAs (miR-143, miR-145, miR-192, miR-194, miR-203, and miR-205) were examined across a discovery cohort of patients with GERD (n = 24) versus Ctrls (n = 24). These findings were confirmed across a validation cohort (GERD, n = 142; Ctrls, n = 48). Differences in miRNA expression levels were evaluated using the Mann-Whitney U test while the specificity and sensitivity were obtained using receiver-operator characteristic (ROC) curves. Results. miR-203 was significantly downregulated in GERD patients as compared to Ctrls (P < 0.0001) with ROC curve of 0.94 (95% CI: 0.90-0.97). The sensitivity and the specificity of miR-203 were 91.7% and 87.3%, respectively, in the GERD and Ctrls. These results suggest that miR-203 may be a useful diagnostic marker for discriminating GERD from Ctrls. Conclusions. miR-203 testing may assist in the diagnosis of patients with symptoms suggestive of GERD.

Yesterday and today of Barrett's esophagus: Historical evolution and research hotspots

It has been more than 60 years since the concept of Barrett's esophagus (BE) was put forward, and over these a few decades, we have made great progress in the diagnosis and treatment of BE. BE does not cause clinical symptoms, but it attracts wide attention, because it is an important precursor lesion of esophageal adenocarcinoma. The purpose of this article is to review the process of the recognition of BE and the current research hotspots as well as to discuss the current status of esophageal adenocarcinoma screening in BE patients. We aim to provide clinicians with an overview of the ins and outs of the disease, which will help them improve the diagnosis and treatment of BE in clinical practice and provide patients with beneficial treatment.

A Systematic Review of Esophageal MicroRNA Markers for Diagnosis and Monitoring of Barrett's Esophagus

BACKGROUND

Esophageal epithelial microRNAs may be used to diagnose Barrett's esophagus (BE) and possibly monitor its progression to esophageal adenocarcinoma (EAC).

AIMS

We reviewed studies that have investigated this to identify microRNAs with high biomarker potential for screening and disease monitoring in BE.

METHODS

PubMed and EMBASE databases were searched for studies that quantified esophageal epithelial microRNAs. Publications reporting microRNA comparisons of normal, non-dysplastic BE, BE with high-grade dysplasia (HGD), and EAC tissues using both unbiased discovery and independent validation phases were reviewed.

RESULTS

Eleven studies on microRNA expression differences between normal epithelium and non-dysplastic BE (seven studies), HGD (4) or EAC (7), or between non-dysplastic BE and HGD (3) or EAC (6) were identified, and the findings of their validation phase were analyzed. Increased miR-192, -194, and -215, and reduced miR-203 and -205 expression in BE compared to normal was noticed by all 4-6 of the seven studies that examined these microRNAs. In heterogeneity tests of the reported fold-change values, the I (2) statistics were 7.9-17.1 % (all P < 0.05). Elevated miR-192, -194, and -215, and diminished miR-203 and -205 levels were also noted for comparisons of HGD or EAC against normal. In contrast, a consistent microRNA expression difference was absent for the comparisons of HGD or EAC against BE.

CONCLUSIONS

MicroRNAs miR-192, -194, -203, -205, and -215 are promising tissue biomarkers for diagnosing BE. Cross-sectional data suggest that microRNAs may have a limited role in separating BE from HGD/EAC epithelia but need further testing in longitudinal follow-up studies.

Regulatory Role of miR-203 in Occurrence and Progression of Kazakh Esophageal squamous cell carcinoma

Esophageal carcinoma is one of the most common malignant tumors and the Kazakh national minority (ethnic) in Xinjiang (northwest of China) has been reported to be one of the highest incidence of Esophageal squamous cell carcinoma (ESCC) in the world. MicroRNA-203 (miR-203) was described as a tumor-suppressive miRNA in several cancers, but little study about the role of miR-203 in Kazakh ESCC. Therefore, we aimed to investigate the role of miR-203 in the occurrence and progression of Kazakh ESCC. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-203 expression, and immunohistochemistry (IHC) was used to examine P63 expression. The expression level of miR-203 in ESCC was significantly lower than that of cancer adjacent normal (CAN) samples (P < 0.05). Whereas the expression level of P63 in ESCC was significantly higher than that of CAN samples (P < 0.05), an inverse association between the expression of P63 and miR-203 was found but was not statistically significant (P > 0.05). These findings suggest that miR-203 is a tumor suppressor gene that plays an important role in inhibiting the occurrence of Kazakh ESCC in Xinjiang, China.

MicroRNA-155 expression inversely correlates with pathologic stage of gastric cancer and it inhibits gastric cancer cell growth by targeting cyclin D1

PURPOSE

MicroRNAs (miRs) have been frequently reported dysregulating in tumors and playing a crucial role in tumor development and progression. However, the expression of miR-155 and its role in gastric cancer (GC) are still obscure.

METHODS

qRT-PCR was applied to detect miR-155 expression in 60 matched GC samples and four GC cell lines, and the relationship between miR-155 levels and clinicopathological features of GC was analyzed. Next, the effects of miR-155 on GC cell growth were evaluated by gain- and loss-of-function analysis. Finally, the target gene(s) of miR-155 in GC cells were explored.

RESULTS

Our results revealed that miR-155 levels were significantly lower in both GC tissues and GC cell lines than in their normal controls, and its expression inversely correlated with tumor size and the pathologic stage. Moreover, our study showed that enforced expression of miR-155 impaired GC cell proliferation, promoted G1 phase arrest and induced apoptosis in vitro. In addition, we identified cyclin D1 as the direct target of miR-155, and knockdown of cyclin D1 partially phenocopied the role of miR-155 in GC cells.

CONCLUSIONS

Our findings suggest that miR-155 may act as a potential diagnostic marker for early-stage GC and may represent a novel therapeutic target for GC treatment.

MicroRNA Expression Signatures During Malignant Progression From Barrett's Esophagus

The rapid increase and poor survival of esophageal adenocarcinoma (EAC) have led to significant efforts to promote early detection. Given that the premalignant lesion of Barrett's esophagus (BE) is the major known risk factor for EAC, multiple investigators have studied biomarker signatures that can predict malignant progression of BE to EAC. MicroRNAs, a novel class of gene regulators, are small non-coding RNAs and have been associated with carcinogenesis. MicroRNAs are ideal biomarkers because of their remarkable stability in fixed tissues, a common method for collection of clinical specimens, and in blood either within exosomes or as microRNA-protein complexes. Multiple studies show potential of microRNAs as tissue and blood biomarkers for diagnosis and prognosis of EAC but the results need confirmation in prospective studies. Although head-to-head comparisons are lacking, microRNA panels require less genes than messenger RNA panels for diagnosis of EAC in BE. MicroRNA diagnostic panels will need to be compared for accuracy against global measures of genome instability that were recently shown to be good predictors of progression but require sophisticated analytic techniques. Early studies on blood microRNA panels are promising but have found microRNA markers to be inconsistent among studies. MicroRNA expression in blood is different between various microRNA sub-compartments such as exosomes and microRNA-protein complexes and could affect blood microRNA measurements. Further standardization is needed to yield consistent results. We have summarized the current understanding of the tissue and blood microRNA signatures that may predict the development and progression of EAC.

Prevention strategies for esophageal cancer: Perspectives of the East vs. West

Esophageal cancer is the eighth most common cancer worldwide. Esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC) are the two major phenotypes in Western and Eastern countries, respectively. Because of different pathways in carcinogenesis, the risk factors and effective steps for prevention of esophageal cancer are different between EAC and ESCC. The carcinogenesis of EAC is initiated by the acid exposure of the esophageal mucosa from stomach while that of the ESCC are related to the chronic irritation of carcinogens mainly by the alcohol, cigarette, betel quid, and hot beverage. To eliminate the burden of esophageal cancer on the global health, the effective strategy should be composed of the primary, secondary, and tertiary prevention. In this article, we perform a systematic review of the preventive strategies for esophageal cancer with special emphasis on the differences from the perspectives of Western and Eastern countries.