miR-7 inhibits the invasion and metastasis of gastric cancer cells by suppressing epidermal growth factor receptor expression

Evaluation of the Rock1 and microRNA-148a expression in biopsies collected from patients with Helicobacter pylori induced gastritis

BACKGROUND

Helicobacter pylori infection is one of the most common chronic bacterial infections, especially in developing countries. MicroRNA-148a is involved in the regulation of various genes, including Rock1, which is altered in gastric cancer. Decreased expression of mir-148a leads to tumor metastasis and increased Rock1 gene expression in gastric cancer. This study aimed to investigate the expression of these genes in biopsies collected from patients with H. pylori induced gastritis.

METHODS

Informed consent forms were gotten from the studied patients with gastritis who needed endoscopy. Gastric biopsies were taken by a gastroenterologist from patients with inflammation. Rapid urease test, stool antigen detection, and histopathological staining were used to determine the H. pylori infected patients. Real time PCR was used to evaluate the miRNA and Rock1 expression levels.

RESULTS

The Rock1 expression level in biopsies that were positive for H. pylori was significantly increased compared to our control gastritis group that were H. pylori-negative, but the results were not statistically significant. Moreover, the mir-148a expression level in H. pylori-positive patients with gastritis was increased compared to our control group. However, the results were not statistically significant. We did not find a significant relation between the expression levels of Rock1 and mir-148a in samples with gastritis infected or uninfected by H. pylori. This result may be due to the small sample size.

CONCLUSION

We suggest that this test should be carried out with more samples, and the comparison should be done between biopsies with inflammation and no inflammation in a patient.

The Role of Methionine Restriction in Gastric Cancer: A Summary of Mechanisms and a Discussion on Tumor Heterogeneity

Gastric cancer is ranked as the fifth most prevalent cancer globally and has long been a topic of passionate discussion among numerous individuals. However, the incidence of gastric cancer in society has not decreased, but instead has shown a gradual increase in recent years. For more than a decade, the treatment effect of gastric cancer has not been significantly improved. This is attributed to the heterogeneity of cancer, which makes popular targeted therapies ineffective. Methionine is an essential amino acid, and many studies have shown that it is involved in the development of gastric cancer. Our study aimed to review the literature on methionine and gastric cancer, describing its mechanism of action to show that tumor heterogeneity in gastric cancer does not hinder the effectiveness of methionine-restricted therapies. This research also aimed to provide insight into the inhibition of gastric cancer through metabolic reprogramming with methionine-restricted therapies, thereby demonstrating their potential as adjuvant treatments for gastric cancer.

Expression of miR-let7b and miR-19b in progressive familial intrahepatic cholestasis (PFIC) children

BACKGROUND

MicroRNAs (miRNAs) are a group of small non-coding RNAs that bind to the target mRNA and regulate gene expression. Recently circulating microRNAs were investigated as markers of diseases and therapeutic targets. Although various studies analyze the miRNA expression in liver disease, these studies on PFIC are few. Progressive familial intrahepatic cholestasis (PFIC) is a rare liver disease with autosomal recessive inheritance. Most children with PFIC progress to cirrhosis and liver failure and consequently need to have a liver transplant. The aim of this study is the investigation of the miR-19b and miR-let7b expression levels in Iranian PFIC children.

METHODS

25 PFIC patients, 25 healthy children and 25 Biliary Atresia patients were considered as case and two control groups respectively. Blood samples were obtained and Liver function tests (LFTs) were measured. After RNA extraction and cDNA synthesis, quantitative PCR was performed using specific primers for miR-19b and miR-let7b. The U6 gene is used as an internal control.

RESULTS

qPCR on PFIC patients' samples demonstrated that the miR-19b and the miR-let7b expression were significantly decreased in patients compared to the control groups, with a p-value<0.0001 and p-value=0.0006 receptively.

CONCLUSION

In conclusion, circulating micro-RNA like miR-19b and miR-let7b have a potential opportunity to be a non-invasive diagnostic marker or therapeutic target for PFIC in the future.

Targeting AXL in Mesothelioma: from functional characterization to clinical implication

Malignant pleural mesothelioma (MM) is a highly aggressive and lethal cancer with a poor survival rate. Current treatment approaches primarily rely on chemotherapy and radiation, but their effectiveness is limited. Consequently, there is an urgent need for alternative treatment strategies, a comprehensive understanding of the molecular mechanisms underlying MM, and the identification of potential therapeutic targets. Extensive studies over the past decade have emphasized the role of Axl in driving tumor development and metastasis, while high levels of Axl expression have been associated with immune evasion, drug resistance, and reduced patient survival in various cancer types. Ongoing clinical trials are investigating the efficacy of Axl inhibitors for different cancers. However, the precise role of Axl in MM progression, development, and metastasis, as well as its regulatory mechanisms within MM, remain inadequately understood. This review aims to comprehensively investigate the involvement of Axl in MM. We discuss Axl role in MM progression, development, and metastasis, along with its specific regulatory mechanisms. Additionally, we examined the Axl associated signaling pathways, the relationship between Axl and immune evasion, and the clinical implications of Axl for MM treatment. Furthermore, we discussed the potential utility of liquid biopsy as a non-invasive diagnostic technique for early detection of Axl in MM. Lastly, we evaluated the potential of a microRNA signature that targets Axl. By consolidating existing knowledge and identifying research gaps, this review contributes to a better understanding of Axl's role in MM and sets the stage for future investigations and the development of effective therapeutic interventions.

The role of microRNA-21 (miR-21) in pathogenesis, diagnosis, and prognosis of gastrointestinal cancers: A review

MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of several target genes. miRNAs play a significant role in cancer biology, as they can downregulate their corresponding target genes by impeding the translation of mRNA (at the mRNA level) as well as degrading mRNAs by binding to the 3'-untranslated (UTR) regions (at the protein level). miRNAs may be employed as cancer biomarkers. Therefore, miRNAs are widely investigated for early detection of cancers which can lead to improved survival rates and quality of life. This is particularly important in the case of gastrointestinal cancers, where early detection of the disease could substantially impact patients' survival. MicroRNA-21 (miR-21 or miRNA-21) is one of the most frequently researched miRNAs, where it is involved in the pathophysiology of cancer and the downregulation of several tumor suppressor genes. In gastrointestinal cancers, miR-21 regulates phosphatase and tensin homolog (PTEN), programmed cell death 4 (PDCD4), mothers against decapentaplegic homolog 7 (SMAD7), phosphatidylinositol 3-kinase /protein kinase B (PI3K/AKT), matrix metalloproteinases (MMPs), β-catenin, tropomyosin 1, maspin, and ras homolog gene family member B (RHOB). In this review, we investigate the functions of miR-21 in pathogenesis and its applications as a diagnostic and prognostic cancer biomarker in four different gastrointestinal cancers, including colorectal cancer (CRC), pancreatic cancer (PC), gastric cancer (GC), and esophageal cancer (EC).

Investigations into the impact of non-coding RNA on the sensitivity of gastric cancer to radiotherapy

Non-coding RNAs (ncRNAs) are a newly discovered functional RNA different from messenger RNA, which can participate in regulating the occurrence and development of tumors. More and more research results show that ncRNAs can participate in the regulation of gastric cancer (GC) radiotherapy response, and its mechanism may be related to its effect on DNA damage repair, gastric cancer cell stemness, cell apoptosis, activation of epidermal growth factor receptor signaling pathway, etc. This article summarizes the relevant mechanisms of ncRNAs regulating the response to radiotherapy in gastric cancer, which will be directly important for the introduction of ncRNAs particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) into clinical medicine as biomarkers and therapeutic targets.

Autophagy-Related ncRNAs in Pancreatic Cancer

Pancreatic cancer (PC) is a malignancy accounting for only 3% of total cancers, but with a low 5-year relative survival rate. Approximately 80% of PC patients are diagnosed at a late stage when the disease has already spread from the primary site. Despite advances in PC treatment, there is an urgently needed for the identification of novel therapeutic strategies for PC, particularly for patients who cannot undergo classical surgery. Autophagy is an evolutionarily conserved process used by cells to adapt to metabolic stress via the degrading or recycling of damaged or unnecessary organelles and cellular components. This process is elevated in PC and, thus, it contributes to the onset, progression, and cancer cell resistance to chemotherapy in pancreatic tumors. Autophagy inhibition has been shown to lead to cancer regression and to increase the sensitivity of pancreatic cells to radiation and chemotherapy. Emerging studies have focused on the roles of non-coding RNAs (ncRNAs), such as miRNAs, long non-coding RNAs, and circular RNAs, in PC development and progression. Furthermore, ncRNAs have been reported as crucial regulators of many biological processes, including autophagy, suggesting that ncRNA-based autophagy targeting methods could be promising novel molecular approaches for specifically reducing autophagic flux, thus improving the management of PC patients. In this review, we briefly summarize the existing studies regarding the role and the regulatory mechanisms of autophagy-related ncRNAs in the context of this cancer.

S100A4 Is a Strong Negative Prognostic Marker and Potential Therapeutic Target in Adenocarcinoma of the Stomach and Esophagus

Deregulated Wnt-signaling is a key mechanism driving metastasis in adenocarcinoma of the gastroesophageal junction and stomach (AGE/S). The oncogene S100A4 was identified as a Wnt-signaling target gene and is known to promote metastasis. In this project, we illuminate the role of S100A4 for metastases development and disease prognosis of AGE/S. Five gastric cancer cell lines were assessed for S100A4 expression. Two cell lines with endogenous high S100A4 expression were used for functional phenotyping including analysis of proliferation and migration after stable S100A4 knock-down. The prognostic value of S100A4 was evaluated by analyzing the S100A4 expression of tissue microarrays with samples of 277 patients with AGE/S. S100A4 knock-down induced lower migration in FLO1 and NCI-N87 cells. Treatment with niclosamide in these cells led to partial inhibition of S100A4 and to reduced migration. Patients with high S100A4 expression showed lower 5-year overall and disease-specific survival. In addition, a larger share of patients in the S100A4 high expressing group suffered from metachronous metastasis. This study identifies S100A4 as a negative prognostic marker for patients with AGE/S. The strong correlation between S100A4 expression, metastases development and patient survival might open opportunities to use S100A4 to improve the prognosis of these patients and as a therapeutic target for intervention in this tumor entity.

Noncoding RNAs and hyperthermic intraperitoneal chemotherapy in advanced gastric cancer

Gastric cancer (GC) is one of the most common malignant tumors globally. About 20-30% of patients with gastric cancer show peritoneal implantation metastasis at the first diagnosis. Peritoneal metastasis is responsible for 70% of deaths of patients with advanced gastric cancer. Although there are many ways to treat advanced gastric cancer, the prognosis of patients with recurrence is unsatisfactory. An auxiliary treatment with hyperthermic intraperitoneal chemotherapy (HIPEC), is an internationally recognized recommended treatment for advanced gastric cancer. A series of clinical trials have shown that HIPEC significantly improves the overall survival of patients with cancer. Compared with the cytoreductive surgery (CRS) alone, HIPEC combined with CRS markedly reduced the rate of peritoneal metastasis in patients with ovarian cancer and colorectal cancer. It has been demonstrated that HIPEC alters transcription of many genes by affecting non-coding RNAs, which may contribute to the suppressive effect of HIPEC on the synthesis of nucleic acids and proteins in cancer cells. This paper reviews the recent advances in understanding the role of non-coding RNAs in tumor invasion and metastasis of advanced gastric cancer. We also consider changes in noncoding RNA levels and other molecules in advanced gastric cancer cases treated with HIPEC. We hope that our review will provide a reference for future research on molecular epidemiology and etiology of advanced gastric cancer and promote precise treatment of this malignancy using HIPEC.

Bone mesenchymal stem cell-derived exosomal microRNA-7-5p inhibits progression of acute myeloid leukemia by targeting OSBPL11

BACKGROUND

Acute myeloid leukemia (AML) is a malignant clonal disease of hematopoietic stem- and progenitor-cell origin. AML features massive proliferation of abnormal blasts and leukemia cells in the bone marrow and the inhibition of normal hematopoiesis at onset. Exosomes containing proteins or nucleic acids are secreted by cells; they participate in intercellular communication and serve as key modulators of hematopoiesis. The purpose of this study was to investigate the effects of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) on the regulation of AML and the underlying mechanisms mediated by microRNA (miRNA).

METHODS

Dysregulated miR-7-5p in AML patients was identified using qRT-PCR and its clinical significance was explored. Bioinformatic analysis revealed the target gene OSBPL11 that could be regulated by miR-7-5p. The findings were validated using a dual-luciferase reporter assay and western blotting. The functional genes of the PI3K/AKT/mTOR signaling pathway were identified, and the functional significance of miR-7-5p in AML cells was determined using a functional recovery assay. AML cells were co-cultured with exosomes originating from BMSCs overexpressing miR-7-5p to determine cell-cell regulation by Exo-miR-7-5p, as well as in vitro and in vivo functional validation via gain- and loss-of-function methods.

RESULTS

Expression of miR-7-5p was decreased in AML patients and cells. Overexpression of miR-7-5p curbed cellular proliferation and promoted apoptosis. Overexpression of OSBPL11 reversed the tumorigenic properties of miR-7-5p in AML cells in vitro. Exo-miR-7-5p derived from BMSCs induced formation of AML cells prone to apoptosis and a low survival rate, with OSBPL11 expression inhibited through the PI3K/AKT/mTOR signaling pathway. Exo-miR-7-5p derived from BMSCs exhibited tumor homing effects in vitro and in vivo, and inhibited AML development.

CONCLUSIONS

Exo-miR-7-5p derived from BMSCs negatively regulates OSBPL11 by suppressing the phosphorylation of the PI3K/AKT/mTOR signaling pathway, thereby inhibiting AML proliferation and promoting apoptosis. The data will inform the development of AML therapies based on BMSC-derived exosomes.

Zinc finger protein 852 is essential for the proliferation, drug sensitivity, and self-renewal of gastric cancer cells

Exploring cellular and molecular mechanisms responsible for gastric cancer growth, survival, self-renewal, and metastasis helps develop efficacious therapeutic strategies. In this study, the expression and function of Zinc finger protein 852 (ZNF852) in human gastric cancer cell lines were characterized. ZNF852 was up-regulated in gastric cancer cell lines relative to normal gastric epithelial cell line GES-1. When the ZNF852 gene was ablated in gastric cancer cell line MGC-803 using the CRISPR/Cas9-encoding lentivirus, the proliferation of MGC-803 was suppressed. ZNF852 deficiency also resulted in the inhibition of MGC-803 sphere formation, along with decreases in SRY-box 2 (SOX2), Octamer-binding transcription factor 4 (OCT4), and Nanog homeobox (NANOG), suggesting that ZNF852 sustains self-renewal of MGC-803 cells. Furthermore, ZNF852 deficiency increased oxaliplatin-induced MGC-803 cell death, implying the role of ZNF852 in drug sensitivity. Subcutaneous infusion of MGC-803 cells into nude mice illustrated the same effects of ZNF852 on the proliferation and self-renewal of gastric cancer cells. Similar effects of ANF852 were also seen in gastric cancer cell line SNU-1. Interestingly, ZNF852 deficiency caused down-regulation of epidermal growth factor receptor (EGFR) on gastric cancer cells. In summary, this study uncovers the positive regulatory role of ZNF852 in gastric cancer growth and maintenance. ZNF852 could be a potential therapeutic target for inhibiting gastric cancer initiation or progression. This article is protected by copyright. All rights reserved.

Linc00467 promotion of gastric cancer development by directly regulating miR-7-5p expression and downstream epidermal growth factor receptor

Linc00467 is a vital regulator in tumor progression. This study explores the molecular mechanisms of linc00467 in gastric cancer (GC). Linc00467 expression was obtained and analyzed in GC tissue through exploration in the cancer genome atlas database. Then, real-time quantitative polymerase chain reaction was used to detect linc000467 expression in GC cells. Cell functions were observed using cell counting Kit-8, Transwell assay, Western blotting to testify the proliferation, migration, invasion, and the relative expression of epidermal growth factor receptor (EGFR) in GC cells. Moreover, a dual-luciferase reporter gene assay was used to verify the relationship between linc00467 and miR-7-5p. Results showed that the expression of linc00467 was overexpressed in GC. Linc00467 silencing decreased the GC cell proliferation, migration, and invasion. With mRNA verification and combined previous research, linc00467 directly regulated the miR-7-5p expression and downstream EGFR expression. Inhibited miR-7-5p could restore cell function, EGFR expression of GC cells when linc00467 knockdown occurs. Altogether, linc00467 directly regulates the miR-7-5p and EGFR signaling pathway to promote GC proliferation, migration, and invasion.

emiRIT: a text-mining-based resource for microRNA information

microRNAs (miRNAs) are essential gene regulators, and their dysregulation often leads to diseases. Easy access to miRNA information is crucial for interpreting generated experimental data, connecting facts across publications and developing new hypotheses built on previous knowledge. Here, we present extracting miRNA Information from Text (emiRIT), a text-miningbased resource, which presents miRNA information mined from the literature through a user-friendly interface. We collected 149 ,233 miRNA –PubMed ID pairs from Medline between January 1997 and May 2020. emiRIT currently contains ‘miRNA –gene regulation’ (69 ,152 relations), ‘miRNA disease (cancer)’ (12 ,300 relations), ‘miRNA –biological process and pathways’ (23, 390 relations) and circulatory ‘miRNAs in extracellular locations’ (3782 relations). Biological entities and their relation to miRNAs were extracted from Medline abstracts using publicly available and in-house developed text-mining tools, and the entities were normalized to facilitate querying and integration. We built a database and an interface to store and access the integrated data, respectively. We provide an up-to-date and user-friendly resource to facilitate access to comprehensive miRNA information from the literature on a large scale, enabling users to navigate through different roles of miRNA and examine them in a context specific to their information needs. To assess our resource’s information coverage, we have conducted two case studies focusing on the target and differential expression information of miRNAs in the context of cancer and a third case study to assess the usage of emiRIT in the curation of miRNA information.

Database URL: https://research.bioinformatics.udel.edu/emirit/

The Multifaceted Role and Utility of MicroRNAs in Indolent B-Cell Non-Hodgkin Lymphomas

Normal B-cell development is a tightly regulated complex procedure, the deregulation of which can lead to lymphomagenesis. One common group of blood cancers is the B-cell non-Hodgkin lymphomas (NHLs), which can be categorized according to the proliferation and spread rate of cancer cells into indolent and aggressive ones. The most frequent indolent B-cell NHLs are follicular lymphoma and marginal zone lymphoma. MicroRNAs (miRNAs) are small non-coding RNAs that can greatly influence protein expression. Based on the multiple interactions among miRNAs and their targets, complex networks of gene expression regulation emerge, which normally are essential for proper B-cell development. Multiple miRNAs have been associated with B-cell lymphomas, as the deregulation of these complex networks can lead to such pathological states. The aim of the present review is to summarize the existing information regarding the multifaceted role of miRNAs in indolent B-cell NHLs, affecting the main B-cell subpopulations. We attempt to provide insight into their biological function, the complex miRNA-mRNA interactions, and their biomarker utility in these malignancies. Lastly, we address the limitations that hinder the investigation of the role of miRNAs in these lymphomas and discuss ways that these problems could be overcome in the future.

Urinary Exosomal MicroRNAs as Potential Non-invasive Biomarkers in Breast Cancer Detection

INTRODUCTION

Breast cancer (BC) is the most frequent malignant disease in women worldwide and is therefore challenging for the healthcare system. Early BC detection remains a leading factor that improves overall outcome and disease management. Aside from established screening procedures, there is a constant demand for additional BC detection methods. Routine BC screening via non-invasive liquid biopsy biomarkers is one auspicious approach to either complete or even replace the current state-of-the-art diagnostics. The study explores the diagnostic potential of urinary exosomal microRNAs with specific BC biomarker characteristics to initiate the potential prospective application of non-invasive BC screening as routine practice.

METHODS

Based on a case-control study (69 BC vs. 40 healthy controls), expression level quantification and subsequent biostatistical computation of 13 urine-derived microRNAs were performed to evaluate their diagnostic relevance in BC.

RESULTS

Multilateral statistical assessment determined and repeatedly confirmed a specific panel of four urinary microRNA types (miR-424, miR-423, miR-660, and let7-i) as a highly specific combinatory biomarker tool discriminating BC patients from healthy controls, with 98.6% sensitivity and 100% specificity.

DISCUSSION

Urine-based BC diagnosis may be achieved through the analysis of distinct microRNA panels with proven biomarker abilities. Subject to further validation, the implementation of urinary BC detection in routine screening offers a promising non-invasive alternative in women's healthcare.

LncRNA LINC00240 suppresses invasion and migration in non-small cell lung cancer by sponging miR-7-5p

Background

lncRNAs have important roles in regulating cancer biology. Accumulating evidence has established a link between the dysregulation of lncRNAs and microRNA in cancer progression. In previous studies, miR-7-5p has been found to be significantly down-regulated in mesenchymal-like lung cancer cell lines and directly regulated EGFR. In this work, we investigated the lncRNA partner of miR-7-5p in the progression of lung cancer.

Methods

We investigated the expression of miR-7-5p and the lncRNA after transfection with an miR-7-5p mimics using a microarray. The microarray results were validated using quantitative real time-polymerase Chain Reaction (qRT-PCR). The regulatory effects of lncRNA on miR-7-5p and its target were evaluated by changes in the expression of miR-7-5p after transfection with siRNAs for lncRNA and the synthesis of full-length lncRNA. The effect of miR-7-5p on lncRNA and the miRNA target was evaluated after transfection with miRNA mimic and inhibitor. The role of lncRNA in cancer progression was determined using invasion and migration assays. The level of lncRNA and EGFR in lung cancer and normal lung tissue was analyzed using TCGA data.

Results

We found that LINC00240 was downregulated in lung cancer cell line after miR-7-5p transfection with an miR-7-5p mimic. Further investigations revealed that the knockdown of LINC00240 induced the overexpression of miR-7-5p. The overexpression of miR-7-5p diminished cancer invasion and migration. The EGFR expression was down regulated after siRNA treatment for LINC00240. Silencing LINC00240 suppressed the invasion and migration of lung cancer cells, whereas LINC00240 overexpression exerted the opposite effect. The lower expression of LINC00240 in squamous lung cancer was analyzed using TCGA data.

Conclusions

Taken together, LINC00240 acted as a sponge for miR-7-5p and induced the overexpression of EGFR. LINC00240 may represent a potential target for the treatment of lung cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07755-8.

Elevated microRNA-7 inhibits proliferation and tumor angiogenesis and promotes apoptosis of gastric cancer cells via repression of Raf-1

OBJECTIVE

Since the essential involvement of microRNAs (miRNAs) in the development and progression of GC, the study was for the exploration of the value of microRNA-7 (miR-7) in the evaluation of neoadjuvant chemotherapy for gastric cancer (GC) and its effects on apoptosis, proliferation and angiogenesis of GC.

METHODS

miR-7 expression in serum of GC patients before and after neoadjuvant chemotherapy were detected to explore its role in neoadjuvant chemotherapy of GC. The GC cells were transfected with miR-7 mimics/inhibitors, or siRNA-Raf-1 to figure out their roles in proliferation, migration, invasion, cycle distribution and apoptosis. Tumor xenograft was conducted to test tumor growth. Microvessel density (MVD) in tumors was tested by immunohistochemical staining.

RESULTS

miR-7 expression in serum of GC patients was lower than that of healthy controls while it was elevated after neoadjuvant chemotherapy. Moreover, higher miR-7 expression was exhibited in chemotherapy-effective patients rather than chemotherapy-ineffective patients (P < 0.01). miR-7 expression in serum was connected with tumor size, degree of differentiation, TNM stage and lymphatic metastasis.miR-7 was decreased and Raf-1 was elevated in GC cells (both P < 0.05). Elevated miR-7 or declined Raf-1 inhibited GC cell migration, proliferation and invasion, cell cycle entry, xenografted tumor growth and MVD and stimulated apoptosis (all P < 0.05). Down-regulated Raf-1 reversed the impacts of miR-7 knockdown on GC cells (all P < 0.05).

CONCLUSION

Our study highlights that elevated miR-27a indicates the good efficacy of neoadjuvant chemotherapy in GC and miR-7 targets Raf-1 to suppress tumor development and angiogenesis of GC cells.

UV-type specific alteration of miRNA expression and its association with tumor progression and metastasis in SCC cell lines

PURPOSE

UV exposure is the main risk factor for development of cutaneous squamous cell carcinoma (cSCC). While early detection greatly improves cSCC prognosis, locally advanced or metastatic cSCC has a severely impaired prognosis. Notably, the mechanisms of progression to metastatic cSCC are not well understood. We hypothesized that UV exposure of already transformed epithelial cSCC cells further induces changes which might be involved in the progression to metastatic cSCCs and that UV-inducible microRNAs (miRNAs) might play an important role.

METHODS

Thus, we analyzed the impact of UV radiation of different quality (UVA, UVB, UVA + UVB) on the miRNA expression pattern in established cell lines generated from primary and metastatic cSCCs (Met-1, Met-4) using the NanoString nCounter platform.

RESULTS

This analysis revealed that the expression pattern of miRNAs depends on both the cell line used per se and on the quality of UV radiation. Comparison of UV-induced miRNAs in cSCC cell lines established from a primary tumor (Met-1) and the respective (un-irradiated) metastasis (Met-4) suggest that miR-7-5p, miR-29a-3p and miR-183-5p are involved in a UV-driven pathway of progression to metastasis. This notion is supported by the fact that these three miRNAs build up a network of 81 potential target genes involved e.g. in UVA/UVB-induced MAPK signaling and regulation of the epithelial-mesenchymal transition. As an example, PTEN, a target of UV-upregulated miRNAs (miR-29a-3p, miR-183-5p), could be shown to be down-regulated in response to UV radiation. We further identified CNOT8, the transcription complex subunit 8 of the CCR4-NOT complex, a deadenylase removing the poly(A) tail from miRNA-destabilized mRNAs, in the center of this network, targeted by all three miRNAs.

CONCLUSION

In summary, our results demonstrate that UV radiation induces an miRNA expression pattern in primary SCC cell line partly resembling those of metastatic cell line, thus suggesting that UV radiation impacts SCC progression beyond initiation.

miR-7-5p Promotes Hepatic Stellate Cell Activation by Targeting Fibroblast Growth Factor Receptor 4

Aims

Fibroblast growth factor receptor 4 (FGFR4) is a key mediator that protects the liver from chronic injury. MicroRNA-7 (miR-7) is a tumor suppressor and associated with lipid homeostasis in the liver. This study was designed to examine the role of the miR-7-5p/FGFR4 axis in liver fibrogenesis.

Methods

TargetScan was employed to predict microRNAs that targeted FGFR4 on the 3'-untranslated region (3'-UTR). miR-7-5p and FGFR4 expression in pathological liver tissues and LX-2 cells was determined using qRT-PCR and an immunoblotting assay. A dual-luciferase assay was conducted to validate the target prediction. A Cell Counting Lit-8 assay was performed to assess the proliferation ability of LX-2 cells. Hydroxyproline content in LX-2 cells was measured using a hydroxyproline assay. The expression of hepatic stellate cell (HSC) activation markers was examined using qRT-PCR and an immunoblotting assay.

Results

FGFR4 was a putative target of miR-7-5p. In LX-2 cells, miR-7-5p targeted FGFR4 by binding to 3'-UTR. FGFR4 was downregulated, but miR-7-5p was markedly enhanced in the liver samples as the degree of liver fibrosis rose. miR-7-5p was negatively associated with FGFR4 expression in liver tissues. The miR-7-5p inhibitor blocked the lipopolysaccharide-induced proliferation and activation of LX-2 cells, and FGFR4 overexpression inhibited LX-2 cell proliferation and activation triggered by miR-7-5p.

Conclusion

miR-7-5p promotes HSC proliferation and activation by downregulating FGFR4.

Down-regulation of lncRNA LINC00152 Suppresses Gastric Cancer Cell Migration and Invasion Through Inhibition of the ERK/MAPK Signaling Pathway

Purpose

The aim of this study was to explore the regulatory role and mechanism of long noncoding RNA LINC00152 in gastric cancer (GC) cells.

Methods

LINC00152 expression in GC tissues and cells was detected by reverse transcription-polymerase chain reaction (qRT-PCR). MKN45 and MGC-803 cells were selected and assigned into different groups after transfection with si-LINC00152, activated ERK/MAPK signaling pathway (SA), or negative control. Cell proliferation, apoptosis, cycle, migration and invasion were assessed by CCK-8, flow cytometry, Transwell assay and Scratch test, respectively. Western blot analysis was conducted to detect the expression of E-cadherin, N-cadherin and ERK/MAPK signaling pathway protein.

Results

Compared with the normal tissues, higher expression of LINC00152 was found in GC tissues and LINC00152 was remarkably correlative with clinical stage and lymphatic metastasis. LINC00152 expression in GC cells was higher than that in GES-1 cells. Compared with the NC group, the cell proliferation rate, cells in G2/M phase, migration and invasion abilities as well as the expression of N-cadherin and p-ERK-1/2 were significantly decreased, and the expression of E-cadherin, cells in G0/G1 phase and cell apoptosis rate were significantly increased in the si-LINC00152-1 group. ERK/MAPK signaling pathway activator SA could reverse the biological role of LINC00152 in GC cells.

Conclusion

These results demonstrated that the interference of LINC00152 expression may inhibit the invasion and migration of GC cells by inhibiting the ERK/MAPK signaling pathway.

MicroRNA-7 Inhibits Rotavirus Replication by Targeting Viral NSP5 In Vivo and In Vitro

Rotavirus (RV) is the major causes of severe diarrhea in infants and young children under five years of age. There are no effective drugs for the treatment of rotavirus in addition to preventive live attenuated vaccine. Recent evidence demonstrates that microRNAs (miRNAs) can affect RNA virus replication. However, the antiviral effect of miRNAs during rotavirus replication are largely unknown. Here, we determined that miR-7 is upregulated during RV replication and that it targets the RV NSP5 (Nonstructural protein 5). Results suggested that miR-7 affected viroplasm formation and inhibited RV replication by down-regulating RV NSP5 expression. Up-regulation of miR-7 expression is a common regulation method of different G-type RV-infected host cells. Then, we further revealed the antiviral effect of miR-7 in diarrhea suckling mice model. MiR-7 is able to inhibit rotavirus replication in vitro and in vivo. These data provide that understanding the role of cellular miR-7 during rotaviral replication may help in the identification of novel therapeutic small RNA molecule drug for anti-rotavirus.

Dissimilar Appearances Are Deceptive-Common microRNAs and Therapeutic Strategies in Liver Cancer and Melanoma

: In this review, we summarize the current knowledge on miRNAs as therapeutic targets in two cancer types that were frequently described to be driven by miRNAs-melanoma and hepatocellular carcinoma (HCC). By focusing on common microRNAs and associated pathways in these-at first sight-dissimilar cancer types, we aim at revealing similar molecular mechanisms that are evolved in microRNA-biology to drive cancer progression. Thereby, we also want to outlay potential novel therapeutic strategies. After providing a brief introduction to general miRNA biology and basic information about HCC and melanoma, this review depicts prominent examples of potent oncomiRs and tumor-suppressor miRNAs, which have been proven to drive diverse cancer types including melanoma and HCC. To develop and apply miRNA-based therapeutics for cancer treatment in the future, it is essential to understand how miRNA dysregulation evolves during malignant transformation. Therefore, we highlight important aspects such as genetic alterations, miRNA editing and transcriptional regulation based on concrete examples. Furthermore, we expand our illustration by focusing on miRNA-associated proteins as well as other regulators of miRNAs which could also provide therapeutic targets. Finally, design and delivery strategies of miRNA-associated therapeutic agents as well as potential drawbacks are discussed to address the question of how miRNAs might contribute to cancer therapy in the future.

MiR-21 in Substance P-induced exosomes promotes cell proliferation and migration in human colonic epithelial cells

Exosomes are cellular vesicles involved in intercellular communication via their specialized molecular cargo, such as miRNAs. Substance P (SP), a neuropeptide/hormone, and its high-affinity receptor, NK-1R, are highly expressed during colonic inflammation. Our previous studies show that SP/NK-1R signaling stimulates differential miRNA expression and promotes colonic epithelial cell proliferation. In this study, we examined whether SP/NK-1R signaling regulates exosome biogenesis and exosome-miRNA cargo sorting. Moreover, we examined the role of SP/NK-1R signaling in exosome-regulated cell proliferation and migration. Exosomes produced by human colonic NCM460 epithelial cells overexpressing NK-1R (NCM460-NK1R) were isolated from culture media. Exosome abundance and uptake were assessed by Western blot analysis (abundance) and Exo-Green fluorescence microscopy (abundance and uptake). Cargo-miRNA levels were assessed by RT-PCR. Cell proliferation and migration were assessed using xCELLigence technology. Colonic epithelial exosomes were isolated from mice pretreated with SP for 3 days. Cell proliferation in vivo was assessed by Ki-67 staining. SP/NK-1R signaling in human colonic epithelial cells (in vitro) and mouse colons (in vivo) increased 1) exosome production, 2) the level of fluorescence in NCM460s treated with Exo-Green-labeled exosomes, and 3) the level of miR-21 in exosome cargo. Moreover, our results showed that SP/NK-1R-induced cell proliferation and migration are at least in part dependent on intercellular communication via exosomal miR-21 in vitro and in vivo. Our results demonstrate that SP/NK-1R signaling regulates exosome biogenesis and induces its miR-21 cargo sorting. Moreover, exosomal miR-21 promotes proliferation and migration of target cells.NEW & NOTEWORTHY Substance P signaling regulates exosome production in human colonic epithelial cells and colonic crypts in wild-type mice. MiR-21 is selectively sorted into exosomes induced by Substance P stimulation and promotes cell proliferation and migration in human colonocytes and mouse colonic crypts.

MiR-7-5p suppresses tumor metastasis of non-small cell lung cancer by targeting NOVA2

Background

Non-small cell lung cancer (NSCLC) is the leading cause of cancer mortality worldwide. Distant metastasis is thought to be one of the most important factors responsible for the failure of NSCLC therapy. MicroRNA-7-5p (miR-7-5p) has been demonstrated to be a tumor suppressor in breast cancer, hepatocarcinoma, prostate cancer and glioblastoma multiforme (GBM). However, its role in NSCLC is still not fully understood. This study evaluated the role of miR-7-5p in the progression of NSCLC and explored the underlying mechanism.

Materials & methods

The quantitative real-time PCR (qPCR), MTT, migration and invasion assays were used to evaluate the effects of miR-7-5p on the proliferation, migration and invasion of A549 and SPCA-1 cells. A tumor xenograft model was created to determine the effects of miR-7-5p on metastasis in vivo. The dual-luciferase reporter gene, neuro-oncological ventral antigen 2 (NOVA2) overexpression and western blotting assays were performed to explore the underlying mechanism.

Results

MiR-7-5p is downregulated in NSCLC tissues and lung cancer cell lines. It suppresses proliferation, migration, invasion and EMT marker expression in vitro and in vivo. Further study showed that miR-7-5p suppresses tumor metastasis of NSCLC by targeting NOVA2. Overexpression of NOVA2 attenuates the miR-7-5p-mediated inhibitory effect on lung cancer cells.

Conclusion

MiR-7-5p suppresses NSCLC metastasis. Targeting miR-7-5p may contribute to the success of NSCLC therapy.

DNA-methylation-mediated silencing of miR-7-5p promotes gastric cancer stem cell invasion via increasing Smo and Hes1

Cancer stem cells are undifferentiated cancer cells that have self-renewal ability, a high tumorigenic activity, and a multilineage differentiation potential. MicroRNAs play a critical role in regulating gene expression during carcinogenesis. Here, we investigated the role of miR-7 and the mechanism by which it is dysregulated in gastric cancer stem cells (GCSCs). The stem cell marker, CD44, was used to sort GCSCs by fluorescence-activated cell sorting. We found that CD44 (+) cells have higher invasiveness and form more number of sphere colonies than CD44 (-) cells. Quantitative real-time polymerase chain reaction (PCR) revealed that the miR-7-5p expression was remarkably downregulated in GCSCs but was significantly increased in the methionine-deprived medium. The downregulation of miR-7-5p results from the increased DNA methylation in the promoter region using the methylation-specific PCR. Overexpression of miR-7-5p reduced the formation of colony and decreased the invasion of GCSCs through targeting Smo and Hes1 and subsequent repressing Notch and Hedgehog signaling pathways in vitro. Notably, upregulating miR-7-5p inhibited the growth of tumor in the xenograft model. Hence, these data demonstrated that miR-7-5p represses GCSC invasion through inhibition of Smo and Hes1, which provides a potential therapeutic target of gastric cancer treatment.

Deregulation of miRNA in Helicobacter pylori-Induced Gastric MALT Lymphoma: From Mice to Human

Gastric MALT lymphoma (GML) is directly caused by Helicobacter pylori infection but occurs only in a small number of infected subjects. Mechanisms underlying the initiation and progression of GML remain unclear. MicroRNAs (miRNAs) are small non-coding RNAs that are now considered as major players in inflammation and carcinogenesis, acting as oncogenes or tumor suppressors. Previous laboratory studies have shown in a GML mouse model that overexpression of a distinct set of five miRNAs (miR-21a, miR-135b, miR-142a, miR-150, miR-155) could play a critical role in the pathogenesis of GML. Our goal was to compare the miRNA expression profile obtained in the GML mouse model to that in human GML (11 cases of GML compared to 17 cases of gastritis control population). RTqPCR on the five dysregulated miRNAs in the GML mouse model and PCR array followed by RTqPCR confirmation showed that four miRNAs were up-regulated (miR-150, miR-155, miR-196a, miR-138) and two miRNAs down-regulated (miR-153, miR-7) in the stomachs of GML patients vs. gastritis control population. The analysis of their validated targets allowed us to postulate that these miRNAs (except miR-138) could act synergistically in a common signaling cascade promoting lymphomagenesis and could be involved in the pathogenesis of GML.

INHBA gene silencing inhibits gastric cancer cell migration and invasion by impeding activation of the TGF-β signaling pathway

Gastric cancer (GC) is the fourth largest cancer in the world, with a 5-year survival rate of <30%. Thus, this study intends to investigate the effects of inhibin βA (INHBA) gene silencing on the migration and invasion of GC cells via the transforming growth factor-β (TGF-β) signaling pathway. Initially, this study determined the expression of INHBA and the TGF-β signaling pathway-related genes in GC tissues. After that, to assess the effect of INHBA silencing on GC progression, GC cells were transfected with short hairpin RNAs that targeted INHBA in order to detect the expression of INHBA and the TGF-β signaling pathway-related genes, as well as cell migration, invasion, and proliferation abilities. Finally, a tumor xenograft model in nude mice was constructed to verify the effect that the silencing of INHBA had on tumor growth. Highly expressed INHBA and activated TGF-β signaling pathways were observed in GC tissues. In response to shINHBA-1 and shINHBA-2, the TGF-β signaling pathway was inhibited in GC cells, whereas the GC cell migration, invasion, proliferation, and tumor growth were significantly dampened. On the basis of the observations and findings of this study, INHBA gene silencing inhibited the progression of GC by inactivating the TGF-β signaling pathway, which provides a potential target in the treatment of GC.

Expression patterns and bioinformatic analysis of miR-1260a and miR-1274a in Prostate Cancer Tunisian patients

Currently, microRNAs (miRs) represent great biomarkers in cancer due to their stability and their potential role in diagnosis, prognosis and therapy. This study aims to evaluate the expression levels of miRs-1260 and -1274a in prostate cancer (PC) samples and to identify their eventual targets by using bioinformatic analysis. In this project, we evaluated the expression status of miRs-1260 and -1274a in 86 PC patients and 19 controls by using real-time quantitative PCR and 2^-ΔΔCt method. Moreover, we retrieved validated and predicted targets of miRs from several datasets by using the "multiMir" R/Bioconductor package. We have found that miRs-1260 and -1274a were over-expressed in PC patients compared to controls (p < 1 × 10^-5). Moreover ROC curve for miRs-1260 and 1274a showed a good performance to distinguish between controls group and PC samples with an area under the ROC curve of 0.897 and 0.784 respectively. However, no significant association could be shown between these two miRs and clinical parameters such as PSA levels, Gleason score, tumor stage, D'Amico classification, lymph node metastasis statues, tumor recurrence, metastasis status and progression after a minimum of 5 years follow-up. Finally, a bioinformatic analysis revealed the association between these two miRs and several targets implicated in prostate cancer initiation pathways.

MicroRNA-622 is a novel mediator of tumorigenicity in melanoma by targeting Kirsten rat sarcoma

The network of molecular players is similar when comparing neural crest-derived, actively migrating melanoblasts to melanoma cells. However, melanoblasts are sensitive to differentiation-initiating signals at their target site (epidermis), while melanoma cells maintain migratory and undifferentiated features. We aimed at identifying downregulated genes in melanoma that are particularly upregulated in melanoblasts. Loss of such genes could contribute to stabilization of a dedifferentiated, malignant phenotype in melanoma. We determined that microRNA-622 (miR-622) expression was strongly downregulated in melanoma cells and tissues compared to melanocytes and melanoblast-related cells. miR-622 expression correlated with survival of patients with melanoma. miR-622 re-expression inhibited clonogenicity, proliferation, and migration in melanoma. Inhibition of miR-622 in melanocytes induced enhanced migration. Kirsten rat sarcoma (KRAS) was identified as a major functional target of miR-622 in melanoma. We conclude that miR-622 is a novel tumor suppressor in melanoma and identify the miR-622-KRAS axis as potential therapeutic target.

Effects of Yangzheng Sanjie Decoction-containing serum mediated by microRNA-7 on cell proliferation and apoptosis in gastric cancer

Gastric cancer (GC) is one of the most common types of cancer and a leading cause of cancer-associated mortality. MicroRNAs (miRNAs/miRs) are demonstrated to function as oncomiRs or tumor-suppressor-miRs in GC. miR-7 has been identified to be a tumor suppressor of GC by targeting epidermal growth factor receptor (EGFR). In our previous study, Yangzheng Sanjie Decoction (YZSJD), a traditional Chinese formula, was identified to be effective in alleviating the symptoms and even postponing turnover of precancerous lesions. To elucidate the mechanism of YZSJD, the present study evaluated the effects of YZSJD of the GC MKN-45 cell line and investigated the underlying molecular mechanisms using YZSJD-containing serum (YCS). The expression of miR-7 in GC, normal and adjacent tissue samples was examined. The results demonstrated that YCS inhibited proliferation by inducing cell cycle arrest at the S phase, and significantly induced apoptosis compared with the control group. miR-7 was significantly downregulated in GC tissues compared with the matched ones. Using reverse transcription-quantitative polymerase chain reaction and western blot analysis, the expression of miR-7 was inversely associated with EGFR. This indicates that YCS inhibits proliferation and induces apoptosis of GC cells mediated by miR-7 targeting EGFR, which may be one of the mechanisms whereby YZSJD exerts its effects on GC.

Seven protective miRNA signatures for prognosis of cervical cancer

Cervical cancer is the second cause of cancer death in females in their 20s and 30s, but there were limited studies about its prognosis. This study aims to identify miRNA related to prognosis and study their functions. TCGA data of patients with cervical cancer were used to build univariate Cox's model with single clinical parameter or miRNA expression level. Multivariate Cox's model was built using both clinical information and miRNA expression levels. At last, STRING was used to enrich gene ontology or pathway for validated targets of significant miRNAs, and visualize the interactions among them. Using univariate Cox's model with clinical parameters, we found that two clinical parameters, tobacco use and clinical stage, and seven miRNAs were highly correlated with the survival status. Only using the expression level of miRNA signatures, the model could separate patients into high-risk and low-risk groups successfully. An optimal feature-selected model was proposed based on two clinical parameters and seven miRNAs. Functional analysis of these seven miRNAs showed they were associated to various pathways related to cancer, including MAPK, VEGF and P53 pathways. These results helped the research of identifying targets for targeted therapy which could potentially allow tailoring of treatment for cervical cancer patients.

miR-7 reverses the resistance to BRAFi in melanoma by targeting EGFR/IGF-1R/CRAF and inhibiting the MAPK and PI3K/AKT signaling pathways

MicroRNAs (miRNAs) are attractive therapeutic targets for various therapy-resistant tumors. However, the association between miRNA and BRAF inhibitor resistance in melanoma remains to be elucidated. We used microarray analysis to comprehensively study the miRNA expression profiling of vemurafenib resistant (VemR) A375 melanoma cells in relation to parental A375 melanoma cells. MicroRNA-7 (miR-7) was identified to be the most significantly down-regulated miRNA in VemR A375 melanoma cells. We also found that miR-7 was down-regulated in Mel-CVR cells (vemurafenib resistant Mel-CV melanoma cells). Reestablishment of miR-7 expression could reverse the resistance of both cells to vemurafenib. We showed that epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R) and CRAF were over-expressed in VemR A375 melanoma cells. Introduction of miR-7 mimics could markedly decrease the expressions of EGFR, IGF-1R and CRAF and further suppressed the activation of MAPK and PI3K/AKT pathway in VemR A375 melanoma cells. Furthermore, tumor growth was inhibited in an in vivo murine VemR A375 melanoma tumor model transfected with miR-7 mimics. Collectively, our study demonstrated that miR-7 could reverse the resistance to BRAF inhibitors in certain vemurafenib resistant melanoma cell lines. It could advance the field and provide the basis for further studies in BRAF inhibitor resistance in melanoma.

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.

The understanding of circular RNAs as special triggers in carcinogenesis

Circular RNAs (circRNAs) are a large type of noncoding RNAs characterized by their circular shape resulting from covalently closed continuous loops. They are known to regulate gene expression in mammals. These tissue-specific transcripts are largely generated from exonic or intronic sequences of their host genes. Although several models of circRNA biogenesis have been proposed, the understanding of their origin is far from complete. Unlike other noncoding RNAs, circRNAs are widely expressed, highly conserved and stable in cytoplasm, which confer special functionalities to them. They are known to serve as microRNA (miRNA) sponges, regulators of alternative splicing, transcription factors and encode for proteins. The expression of circRNAs is associated with several pathological states and may potentially serve as novel diagnostic or predictive biomarkers. CircRNAs are known to regulate the expression of numerous cancer-related miRNAs. The circRNA-miRNA-mRNA axis is a known regulatory pattern of several cancer-associated pathways, with both agonist and antagonist effects on carcinogenesis. In consideration of their potential clinical relevance, circRNAs are at the center of ongoing research initiatives on cancer prevention and treatment. In this review, we discuss the current understanding of circRNAs and the prospects for their potential clinical application in the management of cancer patients.

MicroRNA-7-5p mediates the signaling of hepatocyte growth factor to suppress oncogenes in the MCF-10A mammary epithelial cell

MicroRNA-7 (miR-7) is a non-coding RNA of 23-nucleotides that has been shown to act as a tumor suppressor in various cancers including breast cancer. Although there have been copious studies on the action mechanisms of miR-7, little is known about how the miR is controlled in the mammary cell. In this study, we performed a genome-wide expression analysis in miR-7-transfected MCF-10A breast cell line to explore the upstream regulators of miR-7. Analysis of the dysregulated target gene pool predicted hepatocyte growth factor (HGF) as the most plausible upstream regulator of miR-7. MiR-7 was upregulated in MCF-10A cells by HGF, and subsequently downregulated upon treatment with siRNA against HGF. However, the expression of HGF did not significantly change through either an upregulation or downregulation of miR-7 expression, suggesting that HGF acts upstream of miR-7. In addition, the target genes of miR-7, such as EGFR, KLF4, FAK, PAK1 and SET8, which are all known oncogenes, were downregulated in HGF-treated MCF-10A; in contrast, knocking down HGF recovered their expression. These results indicate that miR-7 mediates the activity of HGF to suppress oncogenic proteins, which inhibits the development of normal cells, at least MCF-10A, into cancerous cells.

Quantitative Proteomics Reveals the Regulatory Networks of Circular RNA CDR1as in Hepatocellular Carcinoma Cells

Circular RNAs (circRNAs), a class of widespread endogenous RNAs, play crucial roles in diverse biological processes and are potential biomarkers in diverse human diseases and cancers. Cerebellar-degeneration-related protein 1 antisense RNA (CDR1as), an oncogenic circRNA, is involved in human tumorigenesis and is dysregulated in hepatocellular carcinoma (HCC). However, the molecular mechanisms underlying CDR1as functions in HCC remain unclear. Here we explored the functions of CDR1as and searched for CDR1as-regulated proteins in HCC cells. A quantitative proteomics strategy was employed to globally identify CDR1as-regulated proteins in HCC cells. In total, we identified 330 differentially expressed proteins (DEPs) upon enhanced CDR1as expression in HepG2 cells, indicating that they could be proteins regulated by CDR1as. Bioinformatic analysis revealed that many DEPs were involved in cell proliferation and the cell cycle. Further functional studies of epidermal growth factor receptor (EGFR) found that CDR1as exerts its effects on cell proliferation at least in part through the regulation of EGFR expression. We further confirmed that CDR1as could inhibit the expression of microRNA-7 (miR-7). EGFR is a validated target of miR-7; therefore, CDR1as may exert its function by regulating EGFR expression via targeting miR-7 in HCC cells. Taken together, we revealed novel functions and underlying mechanisms of CDR1as in HCC cells. This study serves as the first proteome-wide analysis of a circRNA-regulated protein in cells and provides a reliable and highly efficient method for globally identifying circRNA-regulated proteins.

Inhibition of autophagy potentiates the proliferation inhibition activity of microRNA-7 in human hepatocellular carcinoma cells

MicroRNAs (miRNAs/miRs) are important molecules that are able to regulate multiple cellular processes in cancer cells. miR-7 has been previously identified as a tumor suppressive miRNA in several types of cancer. The aim of the present study was to investigate whether miR-7 is able to regulate autophagy in hepatocellular carcinoma (HCC) cells. It was identified that miR-7 was significantly downregulated in tumor tissues compared with adjacent normal tissues. Overexpression of miR-7 inhibited cell proliferative activity, which was partially reversed by miR-7 inhibitor. In addition, overexpression of miR-7 significantly induced an increasen in autophagic activity, and luciferase activity assay and western blot analysis identified that mammalian target of rapamycin (mTOR) was a direct target of miR-7. In addition, inhibition of autophagy by 3-methyladenine resulted in a marked enhancement of the proliferation inhibition effect of miR-7. In conclusion, miR-7 was identified to induce proliferation inhibition and autophagy in HCC cells by targeting mTOR, and inhibition of autophagy may be utilized to enhance the antitumor activity of miR-7.

microRNA-7 impairs autophagy-derived pools of glucose to suppress pancreatic cancer progression

Pancreatic cancer commonly addicts to aerobic glycolysis, and abnormally activates autophagy to adapt the stringent metabolic microenvironment. microRNA-7 (miR-7) was supposed to modulate various gastrointestinal cancer progression. We wonder whether miR-7 could destroy the reprogrammed metabolic homeostasis in pancreatic cancer via modulating the level of autophagy, and further affect tumor proliferation and survival. Herein, we first reported that pancreatic cancer could take advantage of autophagy as a survival strategy to provide essential glucose required for glycolysis metabolism. Of note, under the stressful tumor microenvironment, miR-7 could repress autophagy through up-regulation of LKB1-AMPK-mTOR signaling, and directly targeting the stages of autophagy induction and vesicle elongation to reduce the supply of intracellular glucose to glycolysis metabolism. Furthermore, miR-7 inhibited pancreatic cancer cell proliferation and metastasis in vitro and in vivo. Consistently, lentivirus-mediated miR-7 effectively reduced the growth of patient-derived xenograft by interfering glycolysis via inhibition of autophagy. Together, these data suggested miR-7 might function as an important regulator to impair autophagy-derived pools of glucose to suppress pancreatic cancer progress. Hence, miR-7 might be a potential therapeutic target in pancreatic cancer.

miR-7 Increases Cisplatin Sensitivity of Gastric Cancer Cells Through Suppressing mTOR

MicroRNAs have been reported to play an important role in diverse biological processes and cancer progression. MicroRNA-7 has been observed to be downregulated in human gastric cancer tissues, but the function of microRNA-7 in gastric cancer has not been well investigated. In this study, we demonstrate that the expression of microRNA-7 was significantly downregulated in 30 pairs of human gastric cancer tissues compared to adjacent normal tissues. Enforced expression of microRNA-7 inhibited cell proliferation and migration abilities of gastric cancer cells, BGC823 and SGC7901. Furthermore, microRNA-7 targeted mTOR in gastric cancer cells. In human clinical specimens, mTOR was higher expressed in gastric cancer tissues compared with adjacent normal tissues. More interestingly, microRNA-7 also sensitizes gastric cancer cells to cisplatin (CDDP) by targeting mTOR. Collectively, our results demonstrate that microRNA-7 is a tumor suppressor microRNA and indicate its potential application for the treatment of human gastric cancer in future.

Curcumin exerts its antitumor activity through regulation of miR-7/Skp2/p21 in nasopharyngeal carcinoma cells

Curcumin, a natural polyphenol compound, exhibits tumor suppressive activity in a wide spectrum of cancers, including nasopharyngeal carcinoma cells. However, the exact molecular mechanisms governing this tumor suppressive activity remain elusive. Multiple studies have revealed that miRNAs are critically involved in tumorigenesis, indicating that targeting miRNAs could be a therapeutic strategy for treating human cancer. In the current study, we set out to determine whether curcumin regulates miR-7 expression in nasopharyngeal carcinoma cells. We found that curcumin inhibited cell growth, induced apoptosis, retarded cell migration and invasion, and triggered cell cycle arrest in the human nasopharyngeal carcinoma cell lines CNE1 and CNE2. Importantly, we observed that curcumin upregulated the expression of miR-7 and subsequently inhibited Skp2, a direct miR-7 target. Our results identified that upregulation of miR-7 by curcumin could benefit nasopharyngeal carcinoma patients.

A proposed method for the relative quantification of levels of circulating microRNAs in the plasma of gastric cancer patients

Gastric cancer (GC) is the fifth most common type of malignancy and the third leading cause of cancer-associated mortality worldwide. It is necessary to identify novel methods aimed at improving the early diagnosis and treatment of GC. MicroRNA expression profiles in the plasma of patients with GC have demonstrated a potential use in the opportune diagnosis of this neoplasm. However, there are currently no standardized targets for use in the normalization of microRNA Cq values for different neoplasms. The present study tested two normalization approaches while analyzing plasma derived from patients with GC and non-atrophic gastritis. The first method utilized a panel of small nucleolar RNAs (snoRNAs) and a small nuclear RNA (snRNA) provided by a commercial array. The second normalization approach involved the use of hsa-miR-18a-5p and hsa-miR-29a-3p, which were identified by a stability analysis of the samples being tested. The results revealed that the snoRNAs and snRNA were not expressed in all samples tested. Only the stable microRNAs allowed a narrow distribution of the data and enabled the identification of specific downregulation of hsa-miR-200c-3p and hsa-miR-26b-5p in patients with GC. hsa-miR-200c-3p and hsa-miR-26b-5p have been previously linked to cancer, and a Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that these microRNAs were associated with cell adhesion, cell cycle and cancer pathways.

Significance of microRNA 21 in gastric cancer

Despite promising developments of treatment, the mortality due to gastric cancer remains high and the mechanisms of gastric cancer initiation and the development also remains elusive. It has been reported that patients with positive serologic tests for H. pylori have a higher risk of the development of gastric cancer. microRNAs (miRNAs) are short non-coding RNA molecules consisting of 21-25 nucleotides (nt) in length. The miRNAs silence their cognate target genes by inhibiting mRNA translation or degrading the mRNA molecules by binding to their 3'-untranslated (UTR) regions and plays a very important role in cancer biology. Recent evidences indicate that miR-21 is overexpressed in tumour tissue, including gastric cancer and plays a vital role in tumour cell proliferation, apoptosis, invasion and angiogenesis. Elevated levels of miR-21 is associated with downregulation of tumour suppressor genes, such as programmed cell death 4 (PDCD4), tissue inhibitor of metalloproteinase 3, phosphatase and tensin homolog (PTEN), tropomyosin 1, ras homolog gene family member B, and maspin. Silencing of miR-21 through the use of a miR-21 inhibitor affected cancer cell viability, induced cell cycle arrest and increased chemosensitivity to anticancer agents indicating that miR-21 functions as an oncogene. Although an increased expression level of miR-21 has been observed in gastric cancer, studies related to the role of miR-21 in gastric cancer progression is very limited. The main thrust of this mini review is to explain the potency of miR-21 as a prognostic and/or diagnostic biomarker and as a new target for clinical therapeutic for interventions of gastric cancer progression.

miR-326 Inhibits Gastric Cancer Cell Growth Through Downregulating NOB1

MicroRNAs (miRNAs) play a crucial role in the development and progression of human cancers, including gastric cancer (GC). The discovery of miRNAs may provide a new and powerful tool for studying the mechanism, diagnosis, and treatment of GC. In this study, we aimed to investigate the role of miR-326 in the development and progression of GC. Quantitative PCR (qPCR) was used to measure the expression level of miR-326 in GC tissues and cell lines. We found that miR-326 was significantly downregulated during GC. In addition, overexpression of miR-326 inhibited GC cell proliferation. Fluorescence-activated cell sorting (FACS) further showed that miR-326 significantly induced GC cell G2/M arrest. Subsequent dual-luciferase reporter assay identified one of the proto-oncogene NOB1 as a direct target of miR-326, and NOB1 can save growth inhibition caused by miR-326. We also confirmed that the growth inhibition caused by miR-326 is associated with AKT pathway activation. Taken together, our results indicate that miR-326 could serve as a potential diagnostic biomarker and therapeutic option for GC in the near future.

The roles of microRNAs related with progression and metastasis in human cancers

Metastasis is an important factor in predicting the prognosis of the patients with cancers and contributes to high cancer-related mortality. Recent studies indicated that microRNAs (miRNAs) played a functional role in the initiation and progression of human malignancies. MicroRNAs are small non-coding RNAs of about 22 nucleotides in length that can induce messenger RNA (mRNA) degradation or repress mRNA translation by binding to the 3' untranslated region (3'-UTR) of their target genes. Overwhelming reports indicated that miRNAs could regulate cancer invasion and metastasis via epithelial-to-mesenchymal transition (EMT)-related and/or non-EMT-related mechanisms. In this review, we concentrate on the underlying mechanisms of miRNAs in regulating cancer progression and metastasis.

Role of microRNA-7 in digestive system malignancy

There are several malignancies of the digestive system (including gastric, pancreatic and colorectal cancers, and hepatocellular carcinoma), which are the most common types of cancer and a major cause of death worldwide. MicroRNA (miR)-7 is abundant in the pancreas, playing an important role in pancreatic development and endocrine function. Expression of miR-7 is downregulated in digestive system malignancies compared with normal tissue. Although there are contrasting results for miR-7 expression, almost all research reveals that miR-7 is a tumor suppressor, by targeting various genes in specific pathways. Moreover, miR-7 can target different genes simultaneously in different malignancies of the digestive system. By acting on many cytokines, miR-7 is also involved in many gastrointestinal inflammatory diseases as a significant carcinogenic factor. Consequently, miR-7 might be a biomarker or therapeutic target gene in digestive system malignancies.

miR-362-3p targets nemo-like kinase and functions as a tumor suppressor in renal cancer cells

MicroRNAs (miRNAs) have been demonstrated to exhibit abnormal expression patterns in various types of human cancer. The aim of the present study was to identify a novel tumor suppressor microRNA (miR) and investigate its physiological function and mechanism in renal cell carcinoma (RCC). The expression levels of miRNA (miR)‑362‑3p expres were measured in 47 pairs of RCC and adjacent normal tissue samples, using reverse transcription-quantitative polymerase chain reaction analysis. In addition, miR‑362‑3p was transfected into renal cancer cells to investigate its role in the regulation of cell proliferation, migration, invasion, apoptosis and cell cycle. Identification of the target gene of miR‑362‑3p was performed using luciferase reporter assays and western blot analyses. The results demonstrated that the expression levels of miR‑362‑3p were downregulated in the RCC tissue samples, compared with the adjacent normal tissue samples. The upregulation of miR‑362‑3p using a synthesized mimic suppressed the proliferation, migration and invasion of the renal cancer cells, and induced cell apoptosis and G1 phase arrest. Further experiments demonstrated that the overexpression of miR‑362‑3p resulted in decrease expression levels of nemo-like kinase. These results suggested that miR-362-3p functions as a tumor suppressor in RCC, and may serve as a potential molecular target in the treatment of RCC.