MicroRNA-196a/-196b promote cell metastasis via negative regulation of radixin in human gastric cancer

miR-199a and miR-199b facilitate diffuse gastric cancer progression by targeting Frizzled-6

Pathological markers that can monitor the progression of gastric cancer (GC) may facilitate the diagnosis and treatment of patients with diffuse GC (DGC). To identify microRNAs (miRNAs) that can differentiate between early and advanced DGC in the gastric mucosa, miRNA expression profiling was performed using the NanoString nCounter method in human DGC tumors. Ectopic expression of miR-199a and miR-199b (miR-199a/b) in SNU601 human GC cells accelerated the growth rate, viability, and motility of cancer cells and increased the tumor volume and weight in a mouse xenograft model. To study their clinicopathological roles in patients with GC, miR-199a/b levels were measured in human GC tumor samples using in situ hybridization. High miR-199a/b expression level was associated with enhanced lymphovascular invasion, advanced T stage, and lymph-node metastasis. Using the 3'-untranslated region (UTR) luciferase assay, Frizzled-6 (FZD6) was confirmed to be a direct target of miR-199a/b in GC cells. siRNA-mediated depletion of FZD6 enhanced the motility of SNU601 cells, and addback of FZD6 restored cancer cell motility stimulated by miR-199a/b. In conclusion, miR-199a/b promotes DGC progression by targeting FZD6, implying that miR-199a/b can be used as prognostic and diagnostic biomarkers for the disease.

Tumor Microenvironment Remodeling in Gastrointestinal Cancer: Role of miRNAs as Biomarkers of Tumor Invasion

Gastrointestinal (GI) cancers are the most frequent neoplasm, responsible for half of all cancer-related deaths. Metastasis is the leading cause of death from GI cancer; thus, studying the processes that regulate cancer cell migration is of paramount importance for the development of new therapeutic strategies. In this review, we summarize the mechanisms adopted by cancer cells to promote cell migration and the subsequent metastasis formation by highlighting the key role that tumor microenvironment components play in deregulating cellular pathways involved in these processes. We, therefore, provide an overview of the role of different microRNAs in promoting tumor metastasis and their role as potential biomarkers for the prognosis, monitoring, and diagnosis of GI cancer patients. Finally, we relate the possible use of nutraceuticals as a new strategy for targeting numerous microRNAs and different pathways involved in GI tumor invasiveness.

Decreased TSPAN14 Expression Contributes to NSCLC Progression

Tspan14 is a transmembrane protein of the tetraspanin (Tspan) protein family. Different members of the Tspan family can promote or suppress tumor progression. The exact role of Tspan14 in tumor cells is unknown. Earlier, mutational inactivation of the TSPAN14 gene has been proposed to coincide with a low survival rate in NSCLC patients. This study aimed to investigate the correlation of TSPAN14 lack of function with clinicopathological features of NSCLC patients, and to elucidate the role TSPAN14 might have in NSCLC progression. TSPAN14 expression was lower in tumor cells than non-tumor cells in NSCLC patients’ samples. The decreased gene expression was correlated with a low survival rate of patients and was more frequent in patients with aggressive, invasive tumor types. Additionally, the role of decreased TSPAN14 expression in the metastatic potential of cancer cells was confirmed in NSCLC cell lines. The highly invasive NSCLC cell line (NCI-H661) had the lowest TSPAN14 gene and protein expression, whereas the NSCLC cell line with the highest TSPAN14 expression (NCI-H460) had no significant metastatic potential. Finally, silencing of TSPAN14 in these non-metastatic cancer cells caused an increased expression of matrix-degrading enzymes MMP-2 and MMP-9, followed by an elevated capacity of cancer cells to degrade gelatin. The results of this study propose TSPAN14 expression as an indicator of NSCLC metastatic potential and progression.

Novel biomarkers of microRNAs in gastric cancer; an overview from diagnosis to treatment

The fourth frequent disease in the world and the second cause of cancer-related death is gastric cancer (GC). In this way, over 80% of diagnoses are made in the middle to advanced degrees of the disease, underscoring the requirement for innovative biomarkers that can be identified quickly. Meaningly, biomarkers that can complement endoscopic diagnosis and be used to detect patients with a high risk of GC are desperately needed. These biomarkers will allow for the accurate prediction of therapy response and prognosis in GC patients, as well as the development of an optimal treatment strategy for each individual. Conspicoiusly, microRNAs (miRNAs) and small noncoding RNA regulates the expression of target mRNA and thereby modifies critical biological mechanisms. According to the data, abnormally miRNAs expression in GC is linked to tumor growth, carcinogenesis, aggression and distant metastasis. Importantly, miRNA expression patterns and next-generation sequencing (NGS) can also be applied to analyze kinds of tissues and cancers. Given the high death rates and poor prognosis of GC, and the absence of a clinical diagnostic factor that is adequately sensitive to GC, research into novel sensitive and specific markers for GC diagnosis is critical. In this review,we evaluate the latest research findings that suggest the feasibility and clinical utility of miRNAs in GC.

Quercetin exerts anti-inflammatory effects via inhibiting tumor necrosis factor-α-induced matrix metalloproteinase-9 expression in normal human gastric epithelial cells

BACKGROUND

Gastric injury is the most common digestive system disease worldwide and involves inflammation, which can lead to gastric ulcer or gastric cancer (GC). Matrix metallopeptidase-9 [MMP-9 (gelatinase-B)] plays an important role in inflammation and GC progression. Quercetin and quercetin-rich diets represent potential food supplements and a source of medications for treating gastric injury given their anti-inflammatory activities. However, the effects and mechanisms of action of quercetin on human chronic gastritis and whether quercetin can relieve symptoms remain unclear.

AIM

To assess whether tumor necrosis factor-α (TNF-α)-induced MMP-9 expression mediates the anti-inflammatory effects of quercetin in normal human gastric mucosal epithelial cells.

METHODS

The normal human gastric mucosa epithelial cell line GES-1 was used to establish a normal human gastric epithelial cell model of TNF-α-induced MMP-9 protein overexpression to evaluate the anti-inflammatory effects of quercetin. The cell counting Kit-8 assay was used to evaluate the effects of varying quercetin doses on cell viability in the normal GES-1 cell line. Cell migration was measured using Transwell assay. The expression of proto-oncogene tyrosine-protein kinase Src (c-Src), phospho (p)-c-Src, extracellular-signal-regulated kinase 2 (ERK2), p-ERK1/2, c-Fos, p-c-Fos, nuclear factor kappa B (NF-κB/p65), and p-p65 and the effects of their inhibitors were examined using Western blot analysis and measurement of luciferase activity. p65 expression was detected by immunofluorescence. MMP-9 mRNA and protein levels were measured by quantitative reverse transcription polymerase chain reaction (qRT–PCR) and gelatin zymography, respectively.

RESULTS

qRT-PCR and gelatin zymography showed that TNF-α induced MMP-9 mRNA and protein expression in a dose- and time-dependent manner. These effects were reduced by the pretreatment of GES-1 cells with quercetin or a TNF-α antagonist (TNFR inhibitor) in a dose- and time-dependent manner. Quercetin and TNF-α antagonists decreased the TNF-α-induced phosphorylation of c-Src, ERK1/2, c-Fos, and p65 in a dose- and time-dependent manner. Quercetin, TNF-α antagonist, PP1, U0126, and tanshinone IIA (TSIIA) reduced TNF-α-induced c-Fos phosphorylation and AP-1–Luciferase (Luc) activity in a dose- and time-dependent manner. Pretreatment with quercetin, TNF-α antagonist, PP1, U0126, or Bay 11-7082 reduced TNF-α-induced p65 phosphorylation and translocation and p65–Luc activity in a dose- and time-dependent manner. TNF-α significantly increased GES-1 cell migration, and these results were reduced by pretreatment with quercetin or a TNF-α antagonist.

CONCLUSION

Quercetin significantly downregulates TNF-α-induced MMP-9 expression in GES-1 cells via the TNFR-c-Src–ERK1/2 and c-Fos or NF-κB pathways.

MicroRNA-196a promotes renal cancer cell migration and invasion by targeting BRAM1 to regulate SMAD and MAPK signaling pathways

Rationale: MicroRNAs (miRNAs) are endogenous ~22nt RNAs that play critical regulatory roles in various biological and pathological processes, including various cancers. Their function in renal cancer has not been fully elucidated. It has been reported that miR-196a can act as oncogenes or as tumor suppressors depending on their target genes. However, the molecular target for miR-196a and the underlying mechanism in miR-196a promoted cell migration and invasion in renal cancer is still not clear.

Methods: The expression, survival and correlation between miR-196a and BRAM1 were investigated using TCGA analysis and validated by RT-PCR and western blot. To visualize the effect of Bram1 on tumor metastasis in vivo, NOD-SCID gamma (NSG) mice were intravenously injected with RCC4 cells (10⁶ cells/mouse) or RCC4 overexpressing Bram1. In addition, cell proliferation assays, migration and invasion assays were performed to examine the role of miR-196a in renal cells in vitro. Furthermore, immunoprecipitation was done to explore the binding targets of Bram1.

Results: TCGA gene expression data from renal clear cell carcinoma patients showed a lower level of Bram1 expression in patients' specimens compared to adjacent normal tissues. Moreover, Kaplan‑Meier survival data clearly show that high expression of Bram1correlates to poor prognosis in renal carcinoma patients. Our mouse metastasis model confirmed that Bram1 overexpression resulted in an inhibition in tumor metastasis. Target-prediction analysis and dual-luciferase reporter assay demonstrated that Bram1 is a direct target of miR-196a in renal cells. Further, our in vitro functional assays revealed that miR-196a promotes renal cell proliferation, migration, and invasion. Rescue of Bram1 expression reversed miR-196a-induced cell migration. MiR-196a promotes renal cancer cell migration by directly targeting Bram1 and inhibits Smad1/5/8 phosphorylation and MAPK pathways through BMPR1A and EGFR.

Conclusions: Our findings thus provide a new mechanism on the oncogenic role of miR-196a and the tumor-suppressive role of Bram1 in renal cancer cells. Dysregulated miR-196a and Bram1 represent potential prognostic biomarkers and may have therapeutic applications in renal cancer.

Anticancer Effects of Helminthostachys zeylanica Ethyl acetate Extracts on Human Gastric Cancer Cells through Downregulation of the TNF-α-activated COX-2-cPLA2-PGE2 Pathway

Background: Gastric cancer (GC) is the second most prevalent cancer worldwide and the eighth most common cause of tumor-related death in Taiwan. Helminthostachys zeylanica, a flavonoid compound, has anti-inflammatory, immunomodulatory, and anticancer effects. We examined whether an extract of H. zeylanica (E1 and E2) has potential as a treatment for GC. Methods: We investigated the effects (pro-apoptosis, pro-autophagy, and antiproliferation ability) of H. zeylanica-E2 on cell viability in healthy gastric epithelial (GES-1) and GC cells (AGS and BGC823). H. zeylanica-E2 was toxic to GC cells but had little or no toxicity to normal cells. Results: In this study, H. zeylanica-E2 induced apoptosis through caspase 3/7, Bcl-2, Bax, cyclooxygenase-2 (COX-2), and cleaved poly (ADP-ribose) polymerase pathways in GC cells. In addition, it increased autophagy by stimulating autophagy-related protein (ATG)5, ATG7, LC3-I/LC3-II, and inhibiting COX-2 activity in GC cells. We also found that H. zeylanica-E2 exhibited antiproliferation ability through cell cycle arrest in G0/G1 and G2/M and suppressed the migration of GC cells. The anticancer effects of H. zeylanica-E2 in GC cells might be mediated partly through inhibition of tumor necrosis factor-α (TNF-α)-activated proinflammatory cytosolic phospholipase A2 (cPLA2)-COX-2-prostaglandin E₂ (PGE₂) pathway. Conclusions: Our results suggest that H. zeylanica-E2 has potential as a novel adjunctive agent for the treatment of GC.

The Modulating Mechanisms of miRNA-196 in Malignancies and Its Prognostic Value: A Systematic Review and Meta-Analysis

Accumulating studies have revealed that up- or downregulated miRNA-196 expression correlates with the prognostic value in various malignancies; however, existing single studies lack robust evidence to elucidate the role of miRNA-196 in malignancy. The pooled results showed that the upregulation of miRNA-196 expression was significantly correlated with unfavorable OS [HR 2.14; 95% confidence interval (CI), 1.78-2.57; p < 0.001)] and worse PFS (HR 2.84; 95% CI, 1.29-6.23, P = 0.01) in various malignancies. According to the regulatory mechanisms, studies shown that multiple tumors associated with transcription processes could be modulated by the miRNA-196 family; correspondingly, the miRNA-196 family exerted biological functions that could be regulated by various molecules. The upregulation of miRNA-196a, miRNA-196b and miRNA-196 expression is correlated with significantly unfavorable OS in multiple malignancies; similarly, miRNA-196 overexpression predicts poor PFS in multiple malignancies. Taken together, these findings indicate that miRNA-196a and miRNA-196b may serve as oncogenic molecules and may be potential prognostic biomarkers in multiple malignancies.

Assessment of the Diagnostic Efficiency of a Liquid Biopsy Assay for Early Detection of Gastric Cancer

IMPORTANCE

Noninvasive detection of early-stage disease is a key strategy for reducing gastric cancer (GC)-associated patient mortality.

OBJECTIVE

To establish a novel, noninvasive, microRNA (miRNA)-based signature for the early detection of GC using a comprehensive biomarker discovery approach with retrospective and prospective validation.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted in 4 phases using publicly available genome sequences and tissue samples from patients at an academic medical center in Japan, and validated with retrospective multicenter cohorts of patients with GC. Three tissue miRNA data sets were used to identify a miRNA signature that discriminated GC vs normal tissues. The robustness of this signature was assessed in serum from 2 retrospective cohorts of patients with GC. A risk-scoring model was derived, then the performance of the miRNA signature was evaluated in a prospective cohort of patients with GC. The robustness of the miRNA signature was compared with current blood-based markers, and a cost-effectiveness analysis of the miRNA signature against the current practice of endoscopy was performed. All clinical samples used for this study were collected and data analyzed between April 1997 and March 2018.

MAIN OUTCOMES AND MEASURES

Assessment of diagnostic efficiency on the basis of area under the curve (AUC), specificity, and sensitivity.

RESULTS

The data sets for the genome-wide expression profiling analysis stage included 598 total patient samples (284 [55.4%] from men; mean [SE] patient age, 65.7 [0.5] years). The resulting 10-miRNA signature was validated in 2 retrospective GC serum cohorts (586 patients; 348 [59.4%] men, mean [SE] age, 66.0 [0.7] years), which led to the establishment of a 5-miRNA signature (AUC, 0.90; 95% CI, 0.85-0.94) that also exhibited high levels of diagnostic performance in patients with stage I disease (AUC, 0.89; 95% CI, 0.83-0.94). A risk-scoring model was derived and the assay was optimized to a minimal number of miRNAs. The performance of the resulting 3-miRNA signature was then validated in a prospective cohort of patients with GC (349 patients; 124 [70.5%] men, median [range] age, 66.0 [0.66] years). The final 3-miRNA signature (miR-18a, miR-181b, and miR-335) exhibited high diagnostic accuracy in all stages of patients (AUC, 0.86; 95% CI 0.83-0.90), including in patients with stage I disease (AUC, 0.85; 95% CI, 0.79-0.91). Furthermore, this miRNA signature was superior to currently used blood markers and outperformed the endoscopic screening in a cost-effectiveness analysis (incremental cost-effectiveness ratio, CNY ¥16162.5 per quality-adjusted life-year [USD $2304.80 per quality-adjusted life-year]).

CONCLUSIONS AND RELEVANCE

These results suggest the potential clinical significance of the 3-miRNA signature as a noninvasive, cost-effective, and facile assay for the early detection of GC.

Potential Therapeutic Effects of Melatonin Mediate via miRNAs in Cancer

miRNAs are evolutionarily conserved non-coding ribonucleic acids with a length of between 19 and 25 nucleotides. Because of their ability to regulate gene expression, miRNAs have an important function in the controlling of various biological processes, such as cell cycle, differentiation, proliferation, and apoptosis. Owing to the long-standing regulative potential of miRNAs in tumor-suppressive pathways, scholars have recently paid closer attention to the expression profile of miRNAs in various types of cancer. Melatonin, an indolic compound secreted from pineal gland and some peripheral tissues, has been considered as an effective anti-tumor hormone in a wide spectrum of cancers. Furthermore, it induces apoptosis, inhibits tumor metastasis and invasion, and also angiogenesis. A growing body of evidence indicates the effects of melatonin on miRNAs expression in broad spectrum of diseases, including cancer. Due to the long-term effects of the regulation of miRNAs expression, melatonin could be a promising therapeutic factor in the treatment of cancers via the regulation of miRNAs. Therefore, in this review, we will discuss the effects of melatonin on miRNAs expression in various types of cancers.

Hsa-miR-149-5p Suppresses Prostate Carcinoma Malignancy by Suppressing RGS17

Background

MicroRNAs (miRNAs) are key players in the progression of human cancers. While several miRNAs have been reported to regulate the development of tumors, the molecular mechanisms and roles of miR-149-5p in prostate carcinoma (PCa) remain unclear. Our aim was to investigate the interaction and functions of miR-149-5p and RGS17 in PCa.

Methods

Microarray analysis was performed to identify the key miRNA and gene involved in PCa progression. The expression levels of miRNA and mRNA in PCa tissues and cells were verified by qRT-PCR. MTT assay, BrdU proliferation assay and wound-healing assay were applied to assess the effect of miR-149-5p and RGS17 on PCa cells’ viability, proliferation, and migration ability. The association between RGS17 and miR-149-5p was identify using dual-luciferase reporter assay and Western blot assay.

Results

Data analysis indicated the reduction of miR-149-5p expression in PCa tissues and cells. Experimental investigations also showed that this miRNA suppressed the viability, proliferation and migration ability of PCa cells. RGS17 was found to be the target of miR-149-5p, and the low expression of miR-149-5p upregulated RGS17 in PCa tissues and cells. The results of the cell-function assays showed that RGS17 acted as an oncogene in PCa even though its promotive effect could be reversed by miR-149-5p.

Conclusion

This research confirmed that by targeting and inhibiting RGS17, miR-149-5p could suppress PCa development.

Cytoskeletal Remodeling in Cancer

Simple Summary

Cell migration is an essential process from embryogenesis to cell death. This is tightly regulated by numerous proteins that help in proper functioning of the cell. In diseases like cancer, this process is deregulated and helps in the dissemination of tumor cells from the primary site to secondary sites initiating the process of metastasis. For metastasis to be efficient, cytoskeletal components like actin, myosin, and intermediate filaments and their associated proteins should co-ordinate in an orderly fashion leading to the formation of many cellular protrusions-like lamellipodia and filopodia and invadopodia. Knowledge of this process is the key to control metastasis of cancer cells that leads to death in 90% of the patients. The focus of this review is giving an overall understanding of these process, concentrating on the changes in protein association and regulation and how the tumor cells use it to their advantage. Since the expression of cytoskeletal proteins can be directly related to the degree of malignancy, knowledge about these proteins will provide powerful tools to improve both cancer prognosis and treatment.

Abstract

Successful metastasis depends on cell invasion, migration, host immune escape, extravasation, and angiogenesis. The process of cell invasion and migration relies on the dynamic changes taking place in the cytoskeletal components; actin, tubulin and intermediate filaments. This is possible due to the plasticity of the cytoskeleton and coordinated action of all the three, is crucial for the process of metastasis from the primary site. Changes in cellular architecture by internal clues will affect the cell functions leading to the formation of different protrusions like lamellipodia, filopodia, and invadopodia that help in cell migration eventually leading to metastasis, which is life threatening than the formation of neoplasms. Understanding the signaling mechanisms involved, will give a better insight of the changes during metastasis, which will eventually help targeting proteins for treatment resulting in reduced mortality and longer survival.

MiR-196: emerging of a new potential therapeutic target and biomarker in colorectal cancer

Deregulation of microRNAs, as key elements in colorectal cancer (CRC) pathogenesis, is correlated with various stages of this cancer. miR-196 is involved in the initiation and progression of a verity of malignances, especially CRC. miR-196 in CRC cells could target different types of genes with oncogenic and/or tumor suppressor function such as HOX genes, GATA6, SOCS1, SOCS3, ANXA1, DFFA, PDCD4, ZG16 and ING5. Therefore, these genes could be up or down-regulated in cells and subsequently change the capacity of CRC cells in terms of tumor development, progression and, response to therapy. Comprehension of miR-196-associated aberrations underlying the CRC pathogenesis might introduce promising targets for therapy. Additionally, it seems that miR-196 expression profiling, especially circulatory exosomal miR-196, might be useful for diagnosis and prognosis determination of the CRC patients. In this review, at first, we summarize the roles of miR-196 in different types of cancers. After that, a detailed discussion about this miRNA and also their targets in CRC pathogenesis, progression, and response to treatment are represented. Moreover, we highlight the potential utilization of miR-196 and its targets as therapeutic targets and novel biomarkers in early detection and prediction of prognosis in CRC patients.

Non-coding RNAs in gastric cancer

Non-coding RNAs (ncRNAs) are functional RNA molecules that play crucial regulatory roles in many fundamental biological processes. The dysregulation of ncRNAs is significantly associated with the progression of human cancers, including gastric cancer. In this review, we have summarized the oncogenic or tumor-suppressive roles and the regulatory mechanisms of lncRNAs, miRNAs, circRNAs and piRNAs, and have discussed their potential as biomarkers or therapeutic targets in gastric cancer.

Investigating the role and mechanism of microRNA-196a in oral squamous cell carcinoma by targeting FOXO1

Oral squamous cell carcinoma (OSCC) is one of the most prevalent malignancies worldwide. MicroRNAs (miRNAs or miRs) serve crucial roles in the development of OSCC. miR-196a is upregulated in various tumors; however, the role of miR-196a in OSCC remains unclear. This present study aimed to determine the role and underlying mechanism of miR-196a in OSCC cells. Reverse transcription-quantitative PCR (RT-qPCR) was used to measure miR-196a levels in OSCC cells. MTT assays were also performed to determine cell proliferation. Cell migration was detected using wound healing assays and transwell assays, and cell apoptosis was analyzed via flow cytometry. The results indicated that the expression of miR-196a was increased in OSCC cells compared with normal oral squamous cells. TargetScan and luciferase reporter assays also confirmed that forkhead box O1 (FOXO1) was a target gene of miR-196a. It was demonstrated that FOXO1 small interfering RNA significantly promoted SCC9 cell proliferation and migration, and inhibited cell apoptosis. Furthermore, inhibition of miR-196a suppressed SCC9 cell proliferation and migration, and induced cell apoptosis. However, all effects of the miR-196a inhibitor were reversed following FOXO1 inhibition. Western blotting and RT-qPCR were subsequently performed to determine the effect of miR-196a on the PI3K/Akt signaling pathway. In the present study, transfection of miR-196a inhibitor suppressed the expression of phosphorylated (p)-PI3K and p-Akt, and enhanced the levels of FOXO1, while inhibition of FOXO1 exerted the opposite effects. Furthermore, it was demonstrated that miR-196a mimic significantly enhanced SCC9 cell proliferation and migration, and inhibited cell apoptosis. In conclusion, the results indicated that miR-196a serve as an oncogene in OSCCs. Downregulation of miR-196a inhibited the malignant biological processes of OSCC cells by targeting FOXO1. The current results may provide a novel therapeutic strategy for the treatment of patients with OSCC.

miR-200b regulates breast cancer cell proliferation and invasion by targeting radixin

Radixin is an important member of the Ezrin-Radixin-Moesin protein family that is involved in cell invasion, metastasis and movement. microRNA (miR)-200b is a well-studied microRNA associated with the development of multiple tumors. Previous bioinformatics analysis has demonstrated that miR-200b has a complementary binding site in the 3'-untranslated region of radixin mRNA. The present study aimed to investigate the role of miR-200b in regulating radixin expression, cell proliferation and invasion in breast cancer. Breast cancer tissues at different Tumor-Node-Metastasis (TNM) stages were collected; breast tissues from patients with hyperplasia were used as a control. miR-200b and radixin mRNA expression levels were tested by reverse transcription-quantitative PCR. Radixin protein expression was detected by western blotting. The highly metastatic MDA-MB-231 cells were divided into four groups and transfected with a miR-negative control (NC), miR-200b mimic, small interfering (si)RNA-NC or siRNA targeting radixin. Cell invasion was evaluated by Transwell assay and cell proliferation was assessed by 5-ethynyl-2'-deoxyuridine staining. Compared with the control group, radixin mRNA expression was significantly higher in breast cancer tissues and increased with TNM stage. miR-200b expression levels exhibited the opposite trend. Radixin mRNA expression in breast cancer cells was notably higher, whereas miR-200b expression was lower compared with that in normal breast epithelial MCF-10A cells. The expression of radixin was higher, whereas miR-200b was lower in MDA-MB-231 cells compared with that in MCF-7 cells. miR-200b mimic or siRNA-radixin transfection downregulated the expression of radixin in MDA-MB-231 cells and attenuated the invasive and proliferative abilities of these cells. miR-200b-knockdown and radixin overexpression were associated with enhanced cell invasion in breast cancer. In conclusion, miR-200b regulates breast cancer cell proliferation and invasion by targeting radixin expression.

DEK Is a Potential Biomarker Associated with Malignant Phenotype in Gastric Cancer Tissues and Plasma

Gastric cancer (GC) is the second most widespread cause of cancer-related mortality worldwide. The discovery of novel biomarkers of oncoproteins can facilitate the development of therapeutic strategies for GC treatment. In this study, we identified novel biomarkers by integrating isobaric tags for relative and absolute quantitation (iTRAQ), a human plasma proteome database, and public Oncomine datasets to search for aberrantly expressed oncogene-associated proteins in GC tissues and plasma. One of the most significantly upregulated biomarkers, DEK, was selected and its expression validated. Our immunohistochemistry (IHC) (n = 92) and quantitative real-time polymerase chain reaction (qRT-PCR) (n = 72) analyses disclosed a marked increase in DEK expression in tumor tissue, compared with paired nontumor mucosa. Importantly, significantly higher preoperative plasma DEK levels were detected in GC patients than in healthy controls via enzyme-linked immunosorbent assay (ELISA). In clinicopathological analysis, higher expression of DEK in both tissue and plasma was significantly associated with advanced stage and poorer survival outcomes of GC patients. Data from receiver operating characteristic (ROC) curve analysis disclosed a better diagnostic accuracy of plasma DEK than carcinoembryonic antigen (CEA), carbohydrate antigen 19.9 (CA 19.9), and C-reactive protein (CRP), highlighting its potential as an effective plasma biomarker for GC. Plasma DEK is also more sensitive in tumor detection than the other three biomarkers. Knockdown of DEK resulted in inhibition of GC cell migration via a mechanism involving modulation of matrix metalloproteinase MMP-2/MMP-9 level and vice versa. Our results collectively support plasma DEK as a useful biomarker for making diagnosis and prognosis of GC patients.

Malignant ascites-derived exosomes promote peritoneal tumor cell dissemination and reveal a distinct miRNA signature in advanced gastric cancer

Peritoneal dissemination (PD) is the most frequent metastasis with poor prognosis in patients with advanced gastric cancer (GC). However, the molecular mechanisms of PD remain poorly defined. Exosomes play a pivotal role in cancer progression. Thus, this study aims to investigate the effects of malignant ascites (MA)-derived exosomes from GC patients on tumor cells and to elucidate the underlying mechanism. In vitro and in vivo analysis showed that compared to exosome-depleted supernatants, exosomes from MA of GC patients promoted invasion of AGS cells by up-regulation of Epithelial-mesenchymal transition (EMT) signaling. In a mouse abdominal xenograft model, the median survival was shorter after MA-derived exosomes treatment than the control group (35.5 days versus 67 days, p = 0.0005). Moreover, 29 exosomal miRNAs from ascites were identified by high throughput sequencing among 8 paired GC patients before and after peritoneal chemotherapy and 3 individuals with non-malignant disease. In summary, MA-derived exosomes from patients with GC promote EMT signaling in GC cells and in mouse peritoneal tumor model. Differential exosomal miRNAs might be targeted therapeutically for inhibiting peritoneal metastasis, which provides new insights for the molecular mechanisms of PD in GC.

MicroRNA-196a/-196b regulate the progression of hepatocellular carcinoma through modulating the JAK/STAT pathway via targeting SOCS2

microRNAs (miRNAs) play essential roles in progression of hepatocellular carcinoma (HCC). However, the roles of miR-196a and miR-196b as well as mechanism in HCC progression remain poorly understood. The expressions of miR-196a, miR-196b and suppressor of cytokine signaling 2 (SOCS2) were measured in HCC tissues and cells by quantitative real-time polymerase chain reaction or immunohistochemistry. HCC progression was investigated by cell proliferation, glycolysis, cycle, clones, apoptosis, and necrosis. The interaction between SOCS2 and miR-196a or miR-196b was explored by luciferase activity and RNA immunoprecipitation analyses. The expressions of proteins in Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway were measured by western blot. A xenograft model was established to investigate the roles of miR-196a or miR-196b in vivo. We found that miR-196a and miR-196b were highly expressed in HCC tissues and cells. High expression of miR-196a or miR-196b was correlated with tumor size, tumor-node-metastasis stage, lymph node metastasis, albumin–bilirubin grade and poor 5-year survival. Knockdown of miR-196a or miR-196b suppressed cell proliferation, glycolysis, cell cycle process, colony formation but induced apoptosis or necrosis in HCC cells. SOCS2 was targeted by miR-196a and miR-196b and its interference ablated abrogation of miR-196a or miR-196b-mediated inhibitory effect on HCC progression. SOCS2 was negatively associated with activation of the JAK/STAT pathway. Besides, knockdown of miR-196a or miR-196b limited xenograft tumor growth by blocking the JAK/STAT pathway. We concluded that downregulation of miR-196a or miR-196b inhibited HCC progression through regulating the JAK/STAT pathway via targeting SOCS2, providing novel targets for prognosis and therapeutics of HCC.

An overview of the multifaceted roles of miRNAs in gastric cancer: Spotlight on novel biomarkers and therapeutic targets

MicroRNAs (miRNAs) are a group of small non-coding RNAs that have displayed strong association with gastric cancer (GC). Through the repression of target mRNAs, miRNAs regulate many biological pathways that are involved in cell proliferation, apoptosis, migration, invasion, metastasis as well as drug resistance. The detection of miRNAs in tissues and in body fluids emerges as a promising method in the diagnosis and prognosis of GC, due to their unique expression pattern in correlation with GC. Notably, miRNAs are also identified as potential therapeutic targets for GC therapy. The present review is thus to highlight the multifaceted roles of miRNAs in GC and in GC therapies, which would give indications for future research.

LncRNA NEAT1 promotes colorectal cancer cell proliferation and migration via regulating glial cell-derived neurotrophic factor by sponging miR-196a-5p

Colorectal cancer (CRC) is the one of the most common malignant tumors worldwide. Recent years, widespread long non-coding RNAs (lncRNAs) have been discovered and are known to regulate gene expression in cancers. However, the roles and underlying mechanisms of lncRNA in CRC remain largely unclear. Here, we firstly revealed that repression of lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) inhibited cell proliferation and migration in HCT116 cells and overexpression of NEAT1 promoted cell proliferation and migration in SW480 cells using CCK8 assay and transwell assay. Then, we found that suppression of NEAT1 increased the miR-196a-5p expression in HCT116 cells, while elevation of NEAT1 decreased the miR-196a-5p expression in SW480 cells using qPCR assay. Furthermore, miR-196a-5p could bind to the predicted binding site of NEAT1. We then found that miR-196a-5p was involved in the role of NEAT1 in CRCs. In addition, we demonstrated that miR-196a-5p mimics inhibited the glial cell-derived neurotrophic factor (GDNF) expression in HCT116 cells and meanwhile, miR-196a-5p inhibitor promoted GDNF expression in SW480 cells using qPCR and western blot analysis. Then, we proved that miR-196a-5p exerted its function via regulating GDNF expression in CRCs. Ultimately, our study demonstrated that NEAT1 exerted its role via miR-196a-5p/GDNF axis in CRCs. In summary, this work provided the first evidence of a NEAT1/miR-196a-5p/GDNF regulatory pathway in CRC.

Long noncoding RNA TUG1 promotes renal cell carcinoma cell proliferation, migration and invasion by downregulating microRNA‑196a

Long noncoding RNA taurine upregulated gene 1 (lncRNA TUG1) and microRNA‑196a (miR‑196a) have been reported to serve important roles in the development of renal cell carcinoma (RCC). However, their potential mechanisms have not been completely elucidated. The aim of the present study was to clarify the biological functions of lncRNA‑TUG1 and miR‑196a, in addition to investigating the interaction between lncRNA‑TUG1 and microRNA‑196a, providing a novel insight into RCC tumorigenesis. The present study comprised two parts. In the first part, lncRNA‑TUG1 was confirmed as an oncogene, via reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analysis, MTT assay, flow cytometry analysis, and migration and invasion assays. In the second part, the association between lncRNA‑TUG1 and miR‑196a, and the molecular mechanism, was illustrated via RT‑qPCR analysis, MTT assay, dual luciferase reporter assay and western blotting. The results of the present study demonstrated that lncRNA‑TUG1 was able to promote RCC cell proliferation, migration and invasion in vitro by suppressing miR‑196a. Additionally, lncRNA‑TUG1 achieved its biological functions by regulating the expression levels of RAC‑α serine/threonine‑protein kinase, mitogen‑activated protein kinase and extracellular signal‑regulated kinase via inhibition of miR‑196a. In conclusion, the present findings proposed a novel potential therapeutic target, the lncRNA‑TUG1‑miR‑196a axis, which may be applicable to the treatment of RCC.

MicroRNAs as potential biomarkers for diagnosis, therapy and prognosis of gastric cancer

Despite the widespread use of endoscopy and conventional tumor biomarkers, gastric cancer (GC) remains one of the most frequent causes of cancer-related deaths worldwide due to its late diagnosis and poor response to treatment. Valuable and practical biomarkers are urgently needed to screen patients with a high risk of GC that can complement endoscopic diagnosis. Such biomarkers will enable the efficient prediction of therapeutic response and prognosis of GC patients and favor the establishment of an effective treatment strategy for each and every patient. MicroRNAs (miRNAs) are a class of small non-coding RNA sequences that play important roles in modulating key biological processes by regulating the expression of target genes. Expectedly, miRNAs are abnormally expressed within the tumor tissue and in associated biological fluids of GC patients including their blood, gastric juice, and urine. Accumulating evidence indicates that miRNAs are potential biomarkers with multiple diagnostic functions for GC. Here, we review recent advances and challenges in using miRNAs, particularly biofluid miRNAs, as GC biomarkers with potential clinical applications including diagnosing, clinically staging, and predicting malignant behaviors, therapy response, recurrence after surgery and survival time.

MicroRNA-focused CRISPR-Cas9 library screen reveals fitness-associated miRNAs

MicroRNAs (miRNAs) are post-transcriptional gene regulators that play important roles in the control of cell fitness, differentiation, and development. The CRISPR-Cas9 gene-editing system is composed of the Cas9 nuclease in complex with a single guide RNA (sgRNA) and directs DNA cleavage at a predetermined site. Several CRISPR-Cas9 libraries have been constructed for genome-scale knockout screens of protein function; however, few libraries have included miRNA genes. Here we constructed a miRNA-focused CRISPR-Cas9 library that targets 1594 (85%) annotated human miRNA stem-loops. The sgRNAs in our LX-miR library are designed to have high on-target and low off-target activity, and each miRNA is targeted by four to five sgRNAs. We used this sgRNA library to screen for miRNAs that affect cell fitness of HeLa or NCI-N87 cells by monitoring the change in frequency of each sgRNA over time. By considering the expression in the tested cells and the dysregulation of the miRNAs in cancer specimens, we identified five HeLa pro-fitness and cervical cancer up-regulated miRNAs (miR-31-5p, miR-92b-3p, miR-146b-5p, miR-151a-3p, and miR-194-5p). Similarly, we identified six NCI-N87 pro-fitness and gastric cancer up-regulated miRNAs (miR-95-3p, miR-181a-5p, miR-188-5p, miR-196b-5p, miR-584-5p, and miR-1304-3p), as well as three anti-fitness and down-regulated miRNAs (let-7a-3p, miR-100-5p, and miR-149-5p). Some of those miRNAs are known to be oncogenic or tumor-suppressive, but others are novel. Taken together, the LX-miR library is useful for genome-wide unbiased screening to identify miRNAs important for cellular fitness and likely to be useful for other functional screens.

Linc00472 suppresses proliferation and promotes apoptosis through elevating PDCD4 expression by sponging miR-196a in colorectal cancer

Long intergenic non-coding RNA Linc00472 has been considered as a tumor suppressor in some cancers. However, the function and mechanism of Linc00472 in colorectal cancer has not been well elucidated. In this study, we found that Linc00472 was down-regulated in colorectal cancer tissues and cells. Elevated Linc00472 expression suppressed proliferation and induced apoptosis in colorectal cancer cells. Moreover, Linc00472 acted as a competing endogenous RNA (ceRNA) of miR-196a to release programmed cell death 4 (PDCD4). Furthermore, miR-196a overexpression or PDCD4 knockdown reversed Linc00472-mediated proliferation inhibition and apoptosis induction in colorectal cancer cells. Ectopic Linc00472 expression hindered tumor growth in vivo. Our study demonstrated that Linc00472 suppressed proliferation and induced apoptosis through up-regulating PDCD4 by decoying miR-196a, which may be an effective therapeutic target for colorectal cancer.

miR-409-3p suppresses the proliferation, invasion and migration of tongue squamous cell carcinoma via targeting RDX

The aim of the present study is to investigate the role of microRNA (miRNA/miR)-409-3p in the proliferation, invasion and migration of tongue squamous cell carcinoma (TSCC) cells via targeting radixin (RDX) gene. The expression of miR-409-3p was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in TSCC tissue and cell lines. The binding of miR-409-3p to RDX was investigated by performing a dual-luciferase reporter gene assay. Tca8113 cells were selected to transfect with miR-409-3p mimic/inhibitor, small interfering (si)-RDX, and miR-409-3p inhibitor + si-RDX, as well as negative control (NC) respectively. The proliferative, migratory and invasive abilities of transfected Tca8113 cells were investigated by cell-counting-kit-8, wound-healing and Transwell assays, respectively. Additionally, a tumor xenograft model was constructed to examine the effects of miR-409-3p on the tumor growth and lymphatic metastasis in nude mice. A significant downregulation was detected in miR-409-3p expression in TSCC tissues and cells (all P<0.05) compared with normal tongue mucosa tissues and cell line, which was associated with lymph node metastasis and tumor-node metastasis staging (both P<0.05). The results from the dual-luciferase reporter gene assay indicated that RDX is a potential target gene of miR-409-3p. Compared with the blank group, a marked reduction in RDX expression, cell proliferation, migration and invasion was detected in the miR-409-3p mimic group and si-RDX group (all P<0.05). Conversely, the reverse was observed in cells that were transfected with the miR-409-3p inhibitor. Furthermore, si-RDX is able to reverse the effect of miR-409-3p inhibitor on cell proliferation, invasion and migration (all P<0.05). The results form the tumor xenograft model of nude mice verified that miR-409-3p mimic is able to inhibit the growth of Tca8113 tumor cells and lymph node metastasis in nude mice. miR-409-3p may delay the proliferation of TSCC cells by inhibiting of RDX so as to decrease its migratory and invasive abilities. Therefore, miR-409-3p may be a potential target for the clinical treatment of TSCC.

MicroRNA-26b inhibits tumor metastasis by targeting the KPNA2/c-jun pathway in human gastric cancer

MicroRNAs (miRNA) play an important role in carcinogenesis. Previously, we identified miR-26b as a significantly downregulated miRNA in gastric cancer (GC) tissues (n = 106) based on differential quantitative RT-PCR (RT-qPCR) miRNA expression profiles. In the current study, we aimed to clarify the potential role of miR-26b and related target genes in GC progression. Downregulation of miR-26b was associated with advanced tumor-node-metastasis stage (TNM stage) and poor 5-year survival rate. Forced expression of miR-26b led to inhibition of GC cell migration and invasion in vitro and lung metastasis formation in vivo. Conversely, depletion of miR-26b had stimulatory effects. Additionally, miR-26b affected GC cell behavior through negative regulation of the metastasis promoter, karyopherin alpha 2 (KPNA2). Ectopic expression of miR-26b induced a reduction in KPNA2 protein levels, confirmed by luciferase assay data showing that miR-26b directly binds to the 3' untranslated regions (UTR) of KPNA2 mRNA. Furthermore, miR-26b and KPNA2 mRNA/protein expression patterns were inversely correlated in GC tissues. Cag A of Helicobacter pylori (Hp) enhanced miR-26b levels through regulation of the KPNA2/c-jun pathway. Taken together, our data indicate that miR-26b plays an anti-metastatic role and is downregulated in GC tissues via the KPNA2/c-jun pathway. Based on the study findings, we propose that miR-26b overexpression or KPNA2/c-jun suppression may have therapeutic potential in inhibiting GC metastasis.

Argininosuccinate synthetase 1 contributes to gastric cancer invasion and progression by modulating autophagy

Argininosuccinate synthetase 1 (ASS1) is a rate-limited enzyme in arginine biosynthesis. The oncogenic potential of ASS1 in terms of prognosis and cancer metastasis in arginine prototrophic gastric cancer (GC) remains unclear at present. We identify differentially expressed proteins in microdissected GC tumor cells relative to adjacent nontumor epithelia by isobaric mass tag for relative and absolute quantitation proteomics analysis. GC cells with stable expression or depletion of ASS1 were further analyzed to identify downstream molecules. We investigated their effects on chemoresistance and cell invasion in the presence or absence of arginine. ASS1 was highly expressed in GC and positively correlated with GC aggressiveness and poor outcome. Depletion of ASS1 led to inhibition of tumor growth and decreased cell invasion via induction of autophagy-lysosome machinery, resulting in degradation of active β-catenin, Snail, and Twist. Ectopic expression of ASS1 in GC cells reversed these effects and protected cancer cells from chemotherapy drug-induced apoptosis via activation of the AKT-mammalian target of rapamycin signaling pathway. ASS1 contributes to GC progression by enhancing aggressive potential resulting from active β-catenin, Snail, and Twist accumulation. Our results propose that ASS1 might contribute to GC metastasis and support its utility as a prognostic predictor of GC.-Tsai, C.-Y., Chi, H.-C., Chi, L.-M., Yang, H.-Y., Tsai, M.-M., Lee, K.-F., Huang, H.-W., Chou, L.-F., Cheng, A.-J., Yang, C.-W., Wang, C.-S., Lin, K.-H. Argininosuccinate synthetase 1 contributes to gastric cancer invasion and progression by modulating autophagy.

Circulating microRNA-196a is an early gastric cancer biomarker

MicroRNA-196a (miRNA-196a) is associated with the development of gastric cancer and metastasis. Intestinal metaplasia and low- or high-grade dysplasia are considered to be precursors of intestinal type gastric cancer. Accordingly, we investigated the expression of plasma miRNA-196a as an early detection biomarker in precancerous gastric lesions and early cancer (pT1a/b), which is otherwise treated with endoscopic submucosal dissection. Our data showed that levels of circulating (plasma) miRNA-196a were higher in patients with precancerous lesions/early gastric adenocarcinoma than in healthy controls. The area under the receiver operating characteristic curve (AUC) for healthy controls vs. intestinal metaplasia was 0.9736; healthy controls vs. low-grade/high-grade dysplasia 0.9495; and healthy controls vs. early gastric cancer 0.9318. These results indicate that circulating miRNA-196a is a novel biomarker for detection of early gastric cancer and its precursor.

MicroRNA profiling study reveals miR-150 in association with metastasis in nasopharyngeal carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs that play a crucial role in pathogenesis of human cancers. Several miRNAs have been shown to involve in nasopharyngeal carcinoma (NPC) pathogenesis through alteration of gene networks. A global view of the miRNA expression profile of clinical specimens would be the best way to screen out the possible miRNA candidates that may be involved in disease pathogenesis. In this study, we investigated the expression profiles of miRNA in formalin-fixed paraffin-embedded tissues from patients with undifferentiated NPC versus non-NPC controls using a miRNA real-time PCR platform, which covered a total of 95 cancer-related miRNAs. Hierarchical cluster analysis revealed that NPC and non-NPC controls were clearly segregated. Promisingly, 10 miRNA candidates were differentially expressed. Among them, 9 miRNAs were significantly up-regulated of which miR-205 and miR-196a showed the most up-regulated in NPC with the highest incidence percentage of 94.1% and 88.2%, respectively, while the unique down-regulated miR-150 was further validated in patient sera. Finally, the in vitro gain-of-function and loss-of-function assays revealed that miR-150 can modulate the epithelial-mesenchymal-transition property in NPC/HK-1 cells and led to the cell motility and invasion. miR-150 may be a potential biomarker for NPC and plays a critical role in NPC tumourigenesis.

Prognostic value of microRNAs in gastric cancer: a meta-analysis

BACKGROUND

Previous articles have reported that expression levels of microRNAs (miRNAs) are associated with survival time of patients with gastric cancer (GC). A systematic review and meta-analysis was performed to study the outcome of it.

DESIGN

Meta-analysis.

METHODS

English studies estimating expression levels of miRNAs with any of survival curves in GC were identified up till March 19, 2017 through performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews by two authors independently. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the correlation between miRNA expression and overall survival (OS).

RESULTS

Sixty-nine relevant articles about 26 miRNAs with 6148 patients were ultimately included. GC patients with high expression of miR-20b (HR=2.38, 95%CI=1.16-4.87), 21 (HR=1.77, 95%CI=1.01-3.08), 106b (HR=1.84, 95%CI=1.15-2.94), 196a (HR=2.66, 95%CI=1.94-3.63), 196b (HR=1.67, 95%CI=1.38-2.02), 214 (HR=1.84, 95%CI=1.27-2.67) or low expression of miR-125a (HR=2.06, 95%CI=1.26-3.37), 137 (HR=3.21, 95%CI=1.68-6.13), 141 (HR=2.47, 95%CI=1.34-4.56), 145 (HR=1.62, 95%CI=1.07-2.46), 146a (HR=2.60, 95%CI=1.63-4.13), 206 (HR=2.85, 95%CI=1.73-4.70), 218 (HR=2.61, 95%CI=1.74-3.92), 451 (HR=1.73, 95%CI=1.19-2.52), 486-5p (HR=2.45, 95%CI=1.65-3.65), 506 (HR=2.07, 95%CI=1.33-3.23) have significantly poor OS (P<0.05).

CONCLUSIONS

In summary, miR-20b, 21, 106b, 125a, 137, 141, 145, 146a, 196a, 196b, 206, 214, 218, 451, 486-5p and 506 demonstrate significantly prognostic value. Among them, miR-20b, 125a, 137, 141, 146a, 196a, 206, 218, 486-5p and 506 are strong biomarkers of prognosis in GC.

The role of miRNA and lncRNA in gastric cancer

Gastric cancer is one of the most common cancers and has the highest mortality rate worldwide. It is worthwhile to explore the mechanism of gastric cancer progression. An increasing number of studies have found that non-coding RNAs including miRNA and lncRNA play important roles in gastric cancer progression. This review summarized the role of ectopic miRNA in gastric cancer proliferation, growth, migration, invasion and apoptosis. Meantime, aberrantly expressed miRNA also received a great deal of attention as potential biomarker for gastric cancer diagnosis and therapy. Over the last decade, lncRNA was considered to regulate gastric cancer progression at the transcript and post-transcript level. At the transcript level, lncRNA induced gastric cancer progression by changing chromatin modification and mRNA stabilization to regulate mRNA and miRNA expression. Furthermore, lncRNA regulated gastric cancer progression by completely combining with miRNA to produce ceRNA or promote protein stabilization at the post-transcript level. Greater attention of miRNA and lncRNA in gastric cancer can provide new insight of mechanism of cancer development and may be acted as a new anticancer target.

miR-543 functions as a tumor suppressor in glioma in vitro and in vivo

Gliomas are the most common primary central nervous system tumors and account for approximately 80% of malignant brain tumors. MicroRNAs (miRNAs) are a class of small non-coding, regulatory RNA molecules that mediate the expression levels of specific proteins. As a member of the miRNA family, miR-543 plays a tumor suppressive or an oncogenic role in different types of tumors. However, the expression and role of miR-543 in glioma remain unknown. In the present study, the expression level of miR-543 in glioma cell lines and tissues was investigated. A series of in vitro and in vivo experiments was then performed to elucidate the function of miR-543 in glioma. Moreover, proteomic profiling was applied in this study to determine the landscape of differentially expressed proteins associated with miR-543-mediated carcinogenesis in glioma. We found that the expression level of miR-543 was greatly downregulated in glioma cell lines and tissues. Furthermore, the expression level of miR-543 was negatively associated with high-grade glioma. Functional studies demonstrated that miR-543 in glioma cells induced apoptosis and inhibited growth, the cell cycle, migration and invasion. In addition, the in vivo study showed that miR-543 suppressed tumorigenicity of glioma cells. In the present study, a label-free quantitative proteomic approach was performed and 339 proteins were identified as dysregulated after miR-543 was overexpressed. Among these dysregulated proteins, 165 were upregulated and 174 were downregulated. Moreover, multiple pathways were significantly enriched and were probably involved in miR-543-mediated tumorigenesis, including RNA degradation and the inositol phosphate metabolism pathway. In conclusion, miR-543 may function as a tumor suppressor in glioma and may serve as a future therapeutic target in therapy for patients with glioma.

Prognostic value of candidate microRNAs in gastric cancer: A validation study

BACKGROUND

Studies have reported the prognostic value of dysregulated microRNAs (miRNAs) in gastric cancer (GC). However, the results demonstrated so far are inconsistent.

OBJECTIVE

To better understand the miRNAs with prognostic relevance.

METHODS

Evaluable miRNAs were selected based on our selection criteria and further analyzed in formalin-fixed paraffin-embedded (FFPE) tissue samples of 169 GC patients using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

A total of 19 miRNAs were selected as candidate miRNAs. Among those miRNAs identified, high expression of miR-21-5p was related to poor overall survival (OS) and disease free survival (DFS) and was identified as an independent prognostic factor. Cases with high level of miR-200c-3p showed poor DFS. Subgroup analysis revealed that high expression of miR-21-5p and miR-222-3p was associated with poor OS and DFS in GC patients not received adjuvant chemotherapy. In male patients, high expression level of miR-21-5p was related to poor OS and DFS.

CONCLUSIONS

The present study confirmed that elevated level of miR-21-5p could serve as an independent predictor for poor OS and DFS of GC patients. Moreover, miR-200c-3p, miR-222-3p might also play important roles in the prognosis of GC patients. Further studies are warranted to validate our findings and identify the functions and mechanisms of these miRNAs.

MiR-26a performs converse roles in proliferation and metastasis of different gastric cancer cells via regulating of PTEN expression

Gastric cancer is the second leading cause of cancer-related death in the world. The exact molecular pathways in gastric cancer need for further study. We herein indicated miR-26a performed converse roles on oncogenicity in different gastric cancer cells. In gastric cancer cells MKN-28, miR-26a promoted cell proliferation, migration and invasion. However, in gastric cancer cells AGS, miR-26a reduced cell proliferation and metastasis. PTEN was identified as a direct target of miR-26a. In MKN-28 cells, PTEN was suppressed by miR-26a through 3'-UTR, and PTEN mediated miR-26a promoting oncogenicity including cell proliferation and metastasis. On the other hand, in AGS cells, the expression of PTEN was enhanced by miR-26a, and PTEN mediated miR-26a reducing oncogenicity. The mechanism in AGS cells may be the indirect regulation of PTEN by miR-26a overcame the direct targeting regulation. The model like MKN-28 cells was concordant with patients with a high level of miR-26a and a low level of PTEN and patients with a low level of miR-26a and a high level of PTEN which showed lower overall survival (OS); the model like AGS cells was concordant with patients with both high level of miR-26a and PTEN and both low level of miR-26a and PTEN which showed higher OS. These findings will facilitate a better understanding of the functions and mechanisms about miR-26a, miR-26a and PTEN are potential combined biomarkers in patients with gastric cancer.

Dysregulation of MicroRNA-196b-5p and MicroRNA-375 in Gastric Cancer

Purpose

Dysregulated microRNAs (miRNAs) can contribute to cancer development by leading to abnormal proliferation of cells, apoptosis, and differentiation. Although several miRNAs that are related to gastric cancer have been identified, the reported results have been inconsistent. The aim of this study was to determine miRNA expression profiles and validate miRNAs up- and down-regulated in gastric cancer.

Materials and Methods

We evaluated 34 primary gastric cancer tissues and paired adjacent nontumorous gastric tissues. Total RNA was extracted, and low-molecular-weight RNAs (<200 nucleotides) were isolated for further analysis. Two pairs of tissues were processed for GeneChip microarray analysis, and the identified up- and down-regulated miRNAs were validated by real-time quantitative polymerase chain reaction (qPCR).

Results

In the set of differentially expressed miRNAs, 5 were overexpressed by more than 2 fold, and 5 were reduced by 2 fold or less in gastric cancer tissues compared with normal gastric tissues. Four of these miRNAs (miR-196b-5p, miR-375, miR-483-5p, and miR-486-5p) were then validated by qPCR, and the relative expression levels of 2 miRNAs (miR-196b-5p and miR-375) were significantly different between cancer and normal tissues.

Conclusions

Our results revealed that the expression of miR-196b-5p and miR-375 significantly correlates with gastric cancer. These miRNAs could therefore serve as diagnostic biomarkers of gastric cancer.

Global DNA methylation patterns in Barrett's esophagus, dysplastic Barrett's, and esophageal adenocarcinoma are associated with BMI, gender, and tobacco use

BACKGROUND

The risk of developing Barrett's esophagus (BE) and/or esophageal adenocarcinoma (EAC) is associated with specific demographic and behavioral factors, including gender, obesity/elevated body mass index (BMI), and tobacco use. Alterations in DNA methylation, an epigenetic modification that can affect gene expression and that can be influenced by environmental factors, is frequently present in both BE and EAC and is believed to play a role in the formation of BE and its progression to EAC. It is currently unknown whether obesity or tobacco smoking influences the risk of developing BE/EAC via the induction of alterations in DNA methylation. To investigate this possibility, we assessed the genome-wide methylation status of 81 esophageal tissues, including BE, dysplastic BE, and EAC epithelia using HumanMethylation450 BeadChips (Illumina).

RESULTS

We found numerous differentially methylated loci in the esophagus tissues when comparing males to females, obese to lean individuals, and smokers to nonsmokers. Differences in DNA methylation between these groups were seen in a variety of functional genomic regions and both within and outside of CpG islands. Several cancer-related pathways were found to have differentially methylated genes between these comparison groups.

CONCLUSIONS

Our findings suggest obesity and tobacco smoking may influence DNA methylation in the esophagus and raise the possibility that these risk factors affect the development of BE, dysplastic BE, and EAC through influencing the epigenetic status of specific loci that have a biologically plausible role in cancer formation.

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.

Advances in Understanding How Heavy Metal Pollution Triggers Gastric Cancer

With the development of industrialization and urbanization, heavy metals contamination has become a major environmental problem. Numerous investigations have revealed an association between heavy metal exposure and the incidence and mortality of gastric cancer. The mechanisms of heavy metals (lead, cadmium, mercury, chromium, and arsenic) contamination leading to gastric cancer are concluded in this review. There are four main potential mechanisms: (1) Heavy metals disrupt the gastric mucosal barrier by decreasing mucosal thickness, mucus content, and basal acid output, thereby affecting the function of E-cadherin and inducing reactive oxygen species (ROS) damage. (2) Heavy metals directly or indirectly induce ROS generation and cause gastric mucosal and DNA lesions, which subsequently alter gene regulation, signal transduction, and cell growth, ultimately leading to carcinogenesis. Exposure to heavy metals also enhances gastric cancer cell invasion and metastasis. (3) Heavy metals inhibit DNA damage repair or cause inefficient lesion repair. (4) Heavy metals may induce other gene abnormalities. In addition, heavy metals can induce the expression of proinflammatory chemokine interleukin-8 (IL-8) and microRNAs, which promotes tumorigenesis. The present review is an effort to underline the human health problem caused by heavy metal with recent development in order to garner a broader perspective.

miR-196a Ameliorates Cytotoxicity and Cellular Phenotype in Transgenic Huntington's Disease Monkey Neural Cells

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by the expansion of polyglutamine (polyQ) tract that leads to motor, cognitive and psychiatric impairment. Currently there is no cure for HD. A transgenic HD nonhuman primate (HD-NHP) model was developed with progressive development of clinical and pathological features similar to human HD, which suggested the potential preclinical application of the HD-NHP model. Elevated expression of miR-196a was observed in both HD-NHP and human HD brains. Cytotoxicity and apoptosis were ameliorated by the overexpression of miR-196a in HD-NHP neural progenitor cells (HD-NPCs) and differentiated neural cells (HD-NCs). The expression of apoptosis related gene was also down regulated. Mitochondrial morphology and activity were improved as indicated by mitotracker staining and the upregulation of CBP and PGC-1α in HD-NPCs overexpressing miR-196a. Here we demonstrated the amelioration of HD cellular phenotypes in HD-NPCs and HD-NCs overexpressing miR-196a. Our results also suggested the regulatory role of miR-196a in HD pathogenesis that may hold the key for understanding molecular regulation in HD and developing novel therapeutics.

MiR-203 inhibits tumor invasion and metastasis in gastric cancer by ATM

Gastric cancer is one of the most common malignancies in the world. A number of miRNAs are aberrantly expressed during the progression of gastric cancer. In this study, we aimed to investigate the role of miR-203 in the invasion and metastasis of gastric cancer and the potential mechanism of the effect of miR-203 on the tumor progression of gastric cancer. Our results showed that miR-203 was significantly downregulated in gastric cancer tissues and cells, while ataxia telangiectasia mutated kinase (ATM) was upregulated in gastric cancer tissues and cells and was directly regulated by miR-203. Ectopic overexpression of miR-203 inhibited the colony formation, migration, and invasion of gastric cancer cells. In addition, miR-203 overexpression significantly suppressed the protein level of Snail and obviously promoted the protein level of E-cadherin in gastric cancer cells. ATM knockdown phenocopied the effect of miR-203 overexpression. These results suggested that miR-203 suppressed the migration and invasion of gastric cancer through regulating the level of ATM-mediated-Snail and E-cadherin. MiR-203 might be a novel therapeutic strategy for the treatment of gastric cancer.

Circulating microRNA-196a/b are novel biomarkers associated with metastatic gastric cancer

miR-196a and/or miR-196b, involved in cancer initiation and progression, are frequently upregulated in tumour tissues. However, the clinical significance of these microRNAs in gastric cancer (GC) remains to be clarified. In the current study, we investigated the potential utility of circulating miR-196a/b as novel biomarkers for early detection and/or metastatic prognosis of GC. The quantitative real time-polymerase chain reaction data revealed markedly higher pre-operative circulating miR-196a and miR-196b levels in GC patients than healthy controls. Receiver-operating characteristics curve analysis showed that circulating miR-196a, miR-196b and combined miR-196a and miR-196b (miR-196a/b) are more effective than carcinoembryonic antigen or carbohydrate antigen 19-9 alone in distinguishing GC patients from healthy controls, with higher sensitivity and specificity. Circulating miR-196a exhibited higher diagnostic capacity than combined miR-196a/b or miR-196b alone, highlighting its potential as an effective plasma biomarker for GC. In clinicopathological analysis, elevated circulating miR-196a/b levels were highly correlated with metastatic potential or more advanced stages of disease and poorer survival. In addition, the expression levels of circulating miR-196a/b were reduced after surgical resection in GC patients. Taken together, we propose that circulating miR-196a/b serve as a more sensitive and specific novel biomarker than carbohydrate antigen 19-9 for GC monitor, diagnosis and prognosis.

Potential Diagnostic, Prognostic and Therapeutic Targets of MicroRNAs in Human Gastric Cancer

Human gastric cancer (GC) is characterized by a high incidence and mortality rate, largely because it is normally not identified until a relatively advanced stage owing to a lack of early diagnostic biomarkers. Gastroscopy with biopsy is the routine method for screening, and gastrectomy is the major therapeutic strategy for GC. However, in more than 30% of GC surgical patients, cancer has progressed too far for effective medical resection. Thus, useful biomarkers for early screening or detection of GC are essential for improving patients’ survival rate. MicroRNAs (miRNAs) play an important role in tumorigenesis. They contribute to gastric carcinogenesis by altering the expression of oncogenes and tumor suppressors. Because of their stability in tissues, serum/plasma and other body fluids, miRNAs have been suggested as novel tumor biomarkers with suitable clinical potential. Recently, aberrantly expressed miRNAs have been identified and tested for clinical application in the management of GC. Aberrant miRNA expression profiles determined with miRNA microarrays, quantitative reverse transcription-polymerase chain reaction and next-generation sequencing approaches could be used to establish sample specificity and to identify tumor type. Here, we provide an up-to-date summary of tissue-based GC-associated miRNAs, describing their involvement and that of their downstream targets in tumorigenic and biological processes. We examine correlations among significant clinical parameters and prognostic indicators, and discuss recurrence monitoring and therapeutic options in GC. We also review plasma/serum-based, GC-associated, circulating miRNAs and their clinical applications, focusing especially on early diagnosis. By providing insights into the mechanisms of miRNA-related tumor progression, this review will hopefully aid in the identification of novel potential therapeutic targets.