MicroRNA-1269b inhibits gastric cancer development through regulating methyltransferase-like 3 (METTL3)

METTL3 as a potential therapeutic target in gastric cancer

Gastric cancer (GC) is one of the leading causes of cancer-related death worldwide. N6-methyladenosine (m6A) modification is the most prominent epigenetic modification of eukaryotic mRNAs, and methyltransferase-like 3 (METTL3), a core component of the methyltransferase complex, catalyzes m6A modification. The results of previous studies indicate that the expression level of METTL3 is significantly elevated in gastric cancer tissues and cells. In addition, fluctuations in m6A levels induced by METTL3 are closely associated with the malignant progression of tumors as well as the poor prognosis of patients with gastric cancer. In this review, we focus on the potential mechanism of METTL3 in gastric cancer, and through our analysis, we suggest that targeting METTL3 could be a new therapeutic tool for treating GC.

Recent advances in the reciprocal regulation of m6A modification with non-coding RNAs and its therapeutic application in acute myeloid leukemia

N6-methyladenosine (m6A) is one of the most common modifications of RNA in eukaryotic cells and is involved in mRNA metabolism, including stability, translation, maturation, splicing, and export. m6A also participates in the modification of multiple types of non-coding RNAs, such as microRNAs, long non-coding RNAs, and circular RNAs, thereby affecting their metabolism and functions. Increasing evidence has revealed that m6A regulators, such as writers, erasers, and readers, perform m6A-dependent modification of ncRNAs, thus affecting cancer progression. Moreover, ncRNAs modulate m6A regulators to affect cancer development and progression. In this review, we summarize recent advances in understanding m6A modification and ncRNAs and provide insights into the interaction between m6A modification and ncRNAs in cancer. We also discuss the potential clinical applications of the mechanisms underlying the interplay between m6A modifications and ncRNAs in acute myeloid leukemia (AML). Therefore, clarifying the mutual regulation between m6A modifications and ncRNAs is of great significance to identify novel therapeutic targets for AML and has great clinical application prospects.

Gastric Cancer in the Era of Epigenetics

Gastric cancer (GC) remains a significant contributor to cancer-related mortality. Novel high-throughput techniques have enlightened the epigenetic mechanisms governing gene-expression regulation. Epigenetic characteristics contribute to molecular taxonomy and give rise to cancer-specific epigenetic patterns. Helicobacter pylori (Hp) infection has an impact on aberrant DNA methylation either through its pathogenic CagA protein or by inducing chronic inflammation. The hypomethylation of specific repetitive elements generates an epigenetic field effect early in tumorigenesis. Epstein-Barr virus (EBV) infection triggers DNA methylation by dysregulating DNA methyltransferases (DNMT) enzyme activity, while persistent Hp-EBV co-infection leads to aggressive tumor behavior. Distinct histone modifications are also responsible for oncogene upregulation and tumor-suppressor gene silencing in gastric carcinomas. While histone methylation and acetylation processes have been extensively studied, other less prevalent alterations contribute to the development and migration of gastric cancer via a complex network of interactions. Enzymes, such as Nicotinamide N-methyltransferase (NNMT), which is involved in tumor's metabolic reprogramming, interact with methyltransferases and modify gene expression. Non-coding RNA molecules, including long non-coding RNAs, circular RNAs, and miRNAs serve as epigenetic regulators contributing to GC development, metastasis, poor outcomes and therapy resistance. Serum RNA molecules hold the potential to serve as non-invasive biomarkers for diagnostic, prognostic or therapeutic applications. Gastric fluids represent a valuable source to identify potential biomarkers with diagnostic use in terms of liquid biopsy. Ongoing clinical trials are currently evaluating the efficacy of next-generation epigenetic drugs, displaying promising outcomes. Various approaches including multiple miRNA inhibitors or targeted nanoparticles carrying epigenetic drugs are being designed to enhance existing treatment efficacy and overcome treatment resistance.

N6-methylation in the development, diagnosis, and treatment of gastric cancer

Gastric cancer (GC) ranks third among cancers in terms of mortality rate worldwide. A clear understanding of the mechanisms underlying the genesis and progression of GC will contribute to clinical decision making. N6-methyladenosine (m6A) is the most abundant among diverse mRNA modification types and regulates multiple facets of RNA metabolism. In recent years, emerging studies have shown that m6A modifications are involved in gastric carcinoma tumorigenesis and progression and can potentially be valuable new prospects for diagnosis and prognosis. This article reviews the recent progress regarding m6A in GC.

New insights into the regulation of METTL3 and its role in tumors

As one of the most abundant epigenetic modifications in RNA, N6-methyladenosine (m6A) affects RNA transcription, splicing, stability, and posttranscriptional translation. Methyltransferase-like 3 (METTL3), a key component of the m6A methyltransferase complex, dynamically regulates target genes expression through m6A modification. METTL3 has been found to play a critical role in tumorigenesis, tumor growth, metastasis, metabolic reprogramming, immune cell infiltration, and tumor drug resistance. As a result, the development of targeted drugs against METTL3 is becoming increasingly popular. This review systematically summarizes the factors that regulate METTL3 expression and explores the specific mechanisms by which METTL3 affects multiple tumor biological behaviors. We aim to provide fundamental support for tumor diagnosis and treatment, at the same time, to offer new ideas for the development of tumor-targeting drugs.

The emerging role of m6A modification of non-coding RNA in gastrointestinal cancers: a comprehensive review

Gastrointestinal (GI) cancer is a series of malignant tumors with a high incidence globally. Although approaches for tumor diagnosis and therapy have advanced substantially, the mechanisms underlying the occurrence and progression of GI cancer are still unclear. Increasing evidence supports an important role for N6-methyladenosine (m6A) modification in many biological processes, including cancer-related processes via splicing, export, degradation, and translation of mRNAs. Under distinct cancer contexts, m6A regulators have different expression patterns and can regulate or be regulated by mRNAs and non-coding RNAs, especially long non-coding RNAs. The roles of m6A in cancer development have attracted increasing attention in epigenetics research. In this review, we synthesize progress in our understanding of m6A and its roles in GI cancer, especially esophageal, gastric, and colorectal cancers. Furthermore, we clarify the mechanism by which m6A contributes to GI cancer, providing a basis for the development of diagnostic, prognostic, and therapeutic targets.

MicroRNA-146a-5p induces cell cycle arrest and enhances apoptosis in gastric cancer via targeting CDC14A

Objective: The present study was designed to investigate the expression of miRNA-146a-5p in gastric cancer (GC) tissues and the paired nonmalignant counterparts, to explore the influences of miRNA-146a-5p on the cell biological behavior of MKN-28 cells (highly metastatic human gastric cancer cells), and to identify the function of abnormal expression of its target gene cell division cycle 14 homolog A (CDC14A) in GC. Methods: We detected the expression of miRNA-146a-5p in formalin-fixed and paraffin-embedded (FFPE) GC tissues through microarray and quantitative real-time polymerase chain reaction (qRT-PCR). Then, we employed cell counting kit-8 (CCK-8) assays, cell cycle assays, and apoptosis analysis to uncover the latent function of miRNA-146a-5p in MKN-28 human GC cells. We also validated the target of miRNA-146a-5p via luciferase reporter assays. Results: miRNA-146a-5p levels were examined in the majority of primary GC tissues and several GC cell lines. As a result, miRNA-146a-5p levels were significantly declined in the GC tissues and cells. In addition, miRNA-146a-5p demonstrated a straight act on its 3'-untranslated region (3'-UTR) of CDC14A mRNA, accordingly decreasing the contents of CDC14A mRNA as well as its protein expression. An inverse correlation between CDC14A and miRNA-146a-5p was observed. Conclusion: The data suggest miRNA-146a-5p may contribute to inducing cell cycle arrest as well as prompting GC cell apoptosis via directly targeting CDC14A. Therefore, miRNA-146a-5p may be a potential indicator of the occurrence and development of GC.

Emerging Mutual Regulatory Roles between m6A Modification and microRNAs

N⁶-metyladenosine (m⁶A), one of the most common RNA methylation modifications in mammals, has attracted extensive attentions owing to its regulatory roles in a variety of physiological and pathological processes. As a reversible epigenetic modification on RNAs, m⁶A is dynamically mediated by the functional interplay among the regulatory proteins of methyltransferases, demethylases and methyl-binding proteins. In recent years, it has become increasingly clear that m⁶A modification is associated with the production and function of microRNAs (miRNAs). In this review, we summarize the specific kinds of m⁶A modification methyltransferases, demethylases and methyl-binding proteins. In particular, we focus on describing the roles of m⁶A modification and its regulatory proteins in the production and function of miRNAs in a variety of pathological and physiological processes. More importantly, we further discuss the mediating mechanisms of miRNAs in m⁶A modification and its regulatory proteins during the occurrence and development of various diseases.

Hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit beta gene as a tumour suppressor in stomach adenocarcinoma

BACKGROUND

Stomach adenocarcinoma (STAD) is the most common type of gastric cancer. In this study, the functions and potential mechanisms of hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit beta (HADHB) in STAD were explored.

METHODS

Different bioinformatics analyses were performed to confirm HADHB expression in STAD. HADHB expression in STAD tissues and cells was also evaluated using western blot, qRT-PCR, and immunohistochemistry. Further, the viability, proliferation, colony formation, cell cycle determination, migration, and wound healing capacity were assessed, and the effects of HADHB on tumour growth, cell apoptosis, and proliferation in nude mice were determined. The upstream effector of HADHB was examined using bioinformatics analysis and dual luciferase reporter assay. GSEA was also employed for pathway enrichment analysis and the expression of Hippo-YAP pathway-related proteins was detected.

RESULTS

The expression of HADHB was found to be low in STAD tissues and cells. The upregulation of HADHB distinctly repressed the viability, proliferation, colony formation, cell cycle progression, migration, invasion, and wound healing of HGC27 cells, while knockdown of HADHB led to opposite effects. HADHB upregulation impeded tumour growth and cell proliferation, and enhanced apoptosis in nude mice. KLF4, whose expression was low in STAD, was identified as an upstream regulator of HADHB. KLF4 upregulation abolished the HADHB knockdown-induced tumour promoting effects in AGS cells. Further, HADHB regulates the Hippo-YAP pathway, which was validated using a pathway rescue assay. Low expression of KLF4 led to HADHB downregulation in STAD.

CONCLUSION

HADHB might function as a tumour suppressor gene in STAD by regulation the Hippo-YAP pathway.

MicroRNA-34c-5p exhibits anticancer properties in gastric cancer by targeting MAP2K1 to inhibit cell proliferation, migration, and invasion

Purpose

Gastric cancer(GC)is one of the deadliest digestive tract tumors worldwide，existing studies suggest that dysregulated expression of microRNAs (miRNAs) plays an important role in the pathogenesis and progression of GC. This study aimed to investigate the expression, biological function, and downstream mechanism of miR-34c-5p in GC, provide new targets for gastric cancer diagnosis and treatment.

Methods

The expression of miR-34c-5p in GC tissues and cell lines was examined by RT-qPCR. Cell wound healing, transwell and cell cloning assays were used to detect the effect of miR-34c-5p on the migration and invasion abilities, respectively, of GC cells. Western blot was performed to detect the expression of related proteins. Bioinformatics analysis was used to predict the binding of MAP2K1 to miR-34c-5p and the targeting relationship was confirmed by dual luciferase reporter assay.

Results

The expression level of miR-34c-5p was significantly decreased in GC tissues and cell lines. miR-34c-5p overexpression inhibited migration, invasion, and colony formation of gastric cancer cells, the related protein E-cadherin expression was significantly increased and N-cadherin, vimentin, and PCNA expression were significantly decreased, while miR-34c-5p knockdown exerted the opposite effects. In addition, the targeting relationship between miR-34c-5p and MAP2K1 was predicted and confirmed, and further confirmed by rescue experiments that MAP2K1 alleviated the inhibitory effect of miR-34c-5p in GC.

Conclusion

MiR-34c-5p is lowly expressed in GC, and it can target MAP2K1 to exert inhibitory effects on GC proliferation, invasion, and migration. These findings provide a promising biomarker and a potential therapeutic target for gastric cancer.

Methyltransferase-like 3 (METTL3) mediated N6-methyladenosine (m6A) modifications facilitate mir-25-3p maturation to promote gastrointestinal stromal tumors (GISTs) progression

BACKGROUND

Methyltransferase-like 3 (METTL3) is an RNA N6-methyladenosine (m6A) methyltransferase, which plays a critical role in micorRNA (miRNAs) processing and maturation, but it is still unclear whether METTL3 regulated miRNAs participates in the regulation of cancer aggressiveness in gastrointestinal stromal tumors (GISTs).

OBJECTIVES

This study was designed to investigate this issue, and uncover the potential underlying mechanisms.

METHODS

the expression of METTL3 in GISTs tissues and cell lines were determined by RT-qPCR and Western blot. Cell proliferation and migration were assessed by colony formation, CCK-8 and Transwell. The mRNA expression of all proteins was detected by RT-qPCR, and tumor xenograft study was applied to confirm the effect of METTL3 on GISTs development in vivo.

RESULTS

In our study, we showed that METTL3 was significantly upregulated in GISTs tissues and cell lines. Functional experiments demonstrated that overexpression of METTL3 promoted GISTs cell malignant biological behavior and tumor growth in vitro and in vivo, and conversely, silencing of METTL3 had opposite effects and suppressed GISTs progression. Further mechanistical experiments verified that METTL3 promoted the maturation of miR-25-3p in an m6A-dependent manner. Similar to METTL3, miR-25-3p was also validated as an oncogene to promote cancer development in GISTs. Finally, our rescuing experiments hinted that silencing of miR-25-3p abrogated the tumor-initiating effects of METTL3 overexpression on GISTs.

CONCLUSION

Collectively, those results indicated that METTL3 played an oncogenic role in GISTs through positively modulating the miR-25-3p in an m6A-dependent manner, and we firstly discussed how the METTL3/m6A/miR-25-3p axis affected GISTs development.

MiR-4733-5p promotes gallbladder carcinoma progression via directly targeting kruppel like factor 7

Gallbladder carcinoma (GBC) is highly aggressive with poor prognosis. Accumulating reports show that miRNAs play critical roles in tumor progression. Previous studies have identified several miRNAs that promoted or inhibited GBC cell proliferation and/or metastasis. Here, we used the Gene Expression Omnibus (GEO) dataset to identify dysregulated miRNAs in GBC, followed by validating the upregulation of the miR-4733-5p and downregulation of kruppel-like factor 7 (KLF7) in GBC biopsies by quantitative real-time PCR (RT-qPCR), in situ hybridization (ISH) staining, and immunohistochemistry (IHC) assays. GBC cell proliferation and invasion capacities mediated by miR-4733-5p were evaluated by a series of function assays in vitro, including CCK-8, colony formation assay, wound healing assay and transwell assay. Xenograft tumor model found that miR-4733-5p promoted GBC tumor growth in vivo. This study clarified that miR-4733-5p was upregulated in GBC and promoted GBC cell proliferation via directly binding to 3' untranslated region (UTR) of KLF, which was downregulated and prohibited the proliferation and migration of GBC cells.

Role of lncRNA FAM83H antisense RNA1 (FAM83H-AS1) in the progression of non-small cell lung cancer by regulating the miR-545-3p/heparan sulfate 6-O-sulfotransferase (HS6ST2) axis

Long non-coding RNAs (lncRNAs) are crucial regulators of cancer pathogenesis and are potentially useful diagnostic and prognostic biomarker tools. FAM83H antisense RNA1 (FAM83H-AS1) has been reported to be a vital regulator of different cancers; however, little attention has been paid to its significance in lung cancer. Non-tumorigenic lung cell line BEAS-2B and adenocarcinoma lung cancer cell lines NCI-H1299 and HCC827 were used in the present study. In addition, RNA immunoprecipitation, Western blotting, quantitative reverse transcription-PCR (qRT-PCR), and luciferase reporter assays were used to dissect the role of FAM83H-AS1 in lung cancer progression. The results revealed that FAM83H-AS1 is highly expressed in lung cancer tissues, and its knockdown inhibits lung cancer cell invasion and proliferation reducing tumor growth in vivo. Besides, we found that FAM83H-AS1 targets miR-545-3p, and a negative correlation exists between their expression in lung cancer tissues. Simultaneously, miR-545-3p negatively regulates heparan sulfate 6-O-sulfotransferase (HS6ST2). Moreover, inhibition of miR-545-3p promoted HS6ST2 protein expression and lung cancer cell invasion. FAM83H-AS1 favors non-small cell lung cancer by targeting the miR-545-3p/HS6ST2 axis, supporting the possibility of developing FAM83H-AS1 as a target for NSCLC intervention.

Multiple transcriptome analysis of Piwil2-induced cancer stem cells, including piRNAs, mRNAs and miRNAs reveals the mechanism of tumorigenesis and development

BACKGROUND

Cancer stem cells play important roles in the process of tumorigenesis. Our research group obtained cancer stem cell-like cells named Piwil2-iCSCs by reprogramming human preputial fibroblasts (FBs) with the PIWIL2 gene, but the mechanism of Piwil2-iCSCs is still unclear.

METHODS

We sequenced the piRNAs, miRNAs and mRNAs of Piwil2-iCSCs and FBs, and analyzed the differences. Gene Ontology (GO) and, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses and gene set enrichment analysis (GSEA) were performed on the differentially expressed (DE) mRNAs. In addition, we analyzed the variable shear events and fusion genes in the Piwil2-iCSCs. Target gene prediction and functional enrichment analysis were performed for the DE miRNAs.

RESULTS

A total of 1119 DE mRNAs, 220 DE piRNAs, and 440 DE miRNAs were obtained between the Piwil2-iCSCs and FBs. Functional enrichment analysis showed that the genes with upregulated expression were mainly involved in DNA repair, mismatch repair, base excision repair, and nucleotide excision repair. Genes with downregulated expression were mainly involved in the TGF-β receptor signaling pathway, senescence and autophagy in cancer. More frequent shear events occurred in Piwil2-iCSCs and FBs, especially in intron retention (IR) events. We also identified three fusion genes MCM3AP-C21orf58, LRRFIP2-CAV3 and TMEM184B-DMC1. Enrichment analysis of DE miRNAs showed that they were associated with apoptosis, the TGF-β signaling pathway, and the stem cell regulatory signaling pathway. In particular, target gene prediction of the top three miRNAs with upregulated expression showed that they targeted SMAD, GREM1 and other genes to participate in the regulation of TGF-β and other pathways.

CONCLUSION

PIWIL2-induced cancer stem cells have significantly altered levels of miRNAs, piRNAs and mRNAs.TGF-β, autophagy, apoptosis and other pathways may play an important role in stem cell development. The occurrence of alternative splicing and fusion genes may be related to the occurrence of cancer stem cells.

miR-1269a and miR-1269b: Emerging Carcinogenic Genes of the miR-1269 Family

miRNAs play an important role in the occurrence and development of human cancer. Among them, hsa-mir-1269a and hsa-mir-1269b are located on human chromosomes 4 and 17, respectively, and their mature miRNAs (miR-1269a and miR-1269b) have the same sequence. miR-1269a is overexpressed in 9 cancers. The high expression of miR-1269a not only has diagnostic significance in hepatocellular carcinoma and non-small cell lung cancer but also is related to the poor prognosis of cancer patients such as esophageal cancer, hepatocellular carcinoma, and glioma. miR-1269a can target 8 downstream genes (CXCL9, SOX6, FOXO1, ATRX, RASSF9, SMAD7, HOXD10, and VASH1). The expression of miR-1269a is regulated by three non-coding RNAs (RP11-1094M14.8, LINC00261, and circASS1). miR-1269a participates in the regulation of the TGF-β signaling pathway, PI3K/AKT signaling pathway, p53 signaling pathway, and caspase-9-mediated apoptotic pathway, thereby affecting the occurrence and development of cancer. There are fewer studies on miR-1269b compared to miR-1269a. miR-1269b is highly expressed in hepatocellular carcinoma, non-small cell lung cancer, oral squamous cell carcinoma, and pharyngeal squamous cell carcinoma, but miR-1269b is low expressed in gastric cancer. miR-1269b can target downstream genes (METTL3, CDC40, SVEP1, and PTEN) and regulate the PI3K/AKT signaling pathway. In addition, sequence mutations on miR-1269a and miR-1269b can affect their regulation of cancer. The current studies have shown that miR-1269a and miR-1269b have the potential to be diagnostic and prognostic markers for cancer. Future research on miR-1269a and miR-1269b can focus on elucidating more of their upstream and downstream genes and exploring the clinical application value of miR-1269a and miR-1269b.At present, there is no systematic summary of the research on miR-1269a and miR-1269b. This paper aims to comprehensively analyze the abnormal expression, diagnostic and prognostic value, and molecular regulatory pathways of miR-1269a and miR-1269b in multiple cancers. The overview in our work can provide useful clues and directions for future related research.

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.

Long non-coding RNA CCL2 promoted gastric cancer function via miR-128/ PARP2 signal pathway

Amounts of studies have revealed long non-coding RNA (lncRNA) was related to the development of gastric cancer. Here, our results suggested the function and regulatory mechanism of CCL2 in gastric cancer. Quantitative polymerase-chain reaction (qPCR) was employed to inspect lncRNA CCL2 and miR-128 expression in normal gastric cell line (GES-1) and tumor cell lines (HGC-27 and MKN-45). The effects of CCL2 and miR-128 were measured via Luciferase reporter test. Western blot was used to check PARP2 protein expression. CCL2 expression and PARP2 protein levels were up-regulated, while miR-128 expression was obviously lower. Meanwhile, CCL2 down-regulating significantly repressed the proliferation, migration, and invasion by regulating miR-128. In addition, we proved miR-128 was a direct target of CCL2 through double luciferase assay and bioinformatics analysis. Moreover, miR-128 markedly inhibited the proliferation, migration, and invasion in gastric cancer. More importantly, miR-128 could reverse the effects of lncRNA CCL2 knocked down. PARP2-si obviously suppressed in gastric cancer proliferation, migration, and invasion. Meanwhile, miR-128 mimic and the knockout of CCL2 distinctly decreased PARP2 protein level. Additionally, luciferase report experiments certificated that PARP2 targeted miR-128, implying PARP2 directly interacted with miR-128 in gastric cancer. More interestingly, the downregulation of PARP could reverse the trend triggered by miR-128 inhibitor in gastric tumor. All over these results showed lncRNA CCL2 played importance of role in gastric tumor via miR-128/PARP2 axis signal pathway. LncRNA CCL2 accelerated gastric cancer progression by regulating miR-128/PARP2 signaling pathway, providing a novel possible strategy for the treatment of gastric cancer.

Aberrant miR-362-3p is Associated with EBV-Infection and Prognosis in Nasopharyngeal Carcinoma and Involved in Tumor Progression by Targeting JMJD2A

Background

Many microRNAs (miRNAs) are involved in the progression of nasopharyngeal carcinoma (NPC). This study aimed to examine the expression and clinical significance of microRNA (miR)-362-3p in NPC, especially in Epstein–Barr virus (EBV)-positive patients, and explore its potential mechanism in NPC progression.

Methods

miR-362-3p levels and Jumonji C domain 2A (JMJD2A) mRNA levels were detected by quantitative real-time PCR. The diagnostic value of miR-362-3p to distinguish NPC patients and EBV-positive cases was evaluated using receiver operating characteristic analysis. The association of miR-362-3p with NPC survival was assessed by Kaplan–Meier curves and Cox regression analysis. NPC cell proliferation, migration and invasion were determined using Cell Counting Kit-8 and Transwell assays, respectively. A luciferase reporter assay was used to confirm the interaction between miR-362-3p and JMJD2A.

Results

miR-362-3p expression was decreased in the serum and tissues of NPC patients and had diagnostic value for screening NPC. According to the survival follow-up, NPC survivors had significantly higher miR-362-3p, and miR-326-3p was demonstrated as an independent prognostic indicator of NPC. Interestingly, it is found that EBV-positive NPC patients and cells had significantly lower miR-362-3p compared with EBV-negative NPC patients and cells and had certain ability to distinguish EBV-positive patients. Moreover, miR-362-3p inhibited the proliferation, migration and invasion of both EBV-positive and -negative NPC cells, and these effects might be mediated by targeting JMJD2A.

Conclusion

Abnormal miR-362-3p expression is related to EBV-infection and prognosis in NPC patients and may be involved in NPC progression by targeting JMJD2A.

Ubiquitin-associated protein 2 like (UBAP2L) enhances growth and metastasis of gastric cancer cells

Ubiquitin-proteasome pathway has emerged as therapeutic targets for cancer. GEPIA database analysis showed that the expression of ubiquitin-associated protein 2 like (UBAP2L) in gastric cancer specimens was significantly higher than that in non-tumor tissue, and its high expression is associated with poor survival of gastric cancer patients. This study aims to investigate the role of UBAP2L in gastric cancer. Real-time PCR and western blot results showed that UBAP2L expression was upregulated in gastric cancer cell lines. Loss- and gain-of-function experiments demonstrated that silencing of UBAP2L inhibited proliferation, migration and invasion, and induced apoptosis of gastric cancer cells, and overexpression of UBAP2L played opposite roles. Nude mice inoculated with UBAP2L-silenced gastric cancer cells generated smaller xenografted tumors in vivo. Furthermore, UBAP2L activated Wnt/β-catenin signaling - the accumulation of nuclear β-catenin and the expression of its downstream targets (cyclin D1, AXIN-2 and c-MYC) was facilitated, whereas knockdown of UBAP2L deactivated this signaling. The tumor-suppressing effect of UBAP2L silencing was abolished by forced activation of β-cateninS33A. UBAP2L has been confirmed as a novel and direct target of miR-148b-3p. The anti-tumor effect of miR-148b-3p was partly reversed by UBAP2L overexpression. The expression of miR-148b-3p was negatively correlated with that of UBAP2L in gastric cancer samples. Overall, our study indicates that UBAP2L is required to maintain malignant behavior of gastric cancer cells, which involves the activation of Wnt/β-catenin signaling pathway. We propose UBAP2L as a potential therapeutic target against gastric cancer.

PIWI interacting RNAs perspectives: a new avenues in future cancer investigations

As a currently identified small non-coding RNAs (ncRNAs) category, the PIWI-interacting RNAs (piRNAs) are crucial mediators of cell biology. The human genome comprises over 30.000 piRNA genes. Although considered a new field in cancer research, the piRNA pathway is shown by the existing evidence as an active pathway in a variety of different types of cancers with critical impacts on main aspects of cancer progression. Among the regulatory molecules that contribute to maintaining the dynamics of cancer cells, the P-element Induced WImpy testis (PIWI) proteins and piRNAs, as new players, have not been broadly studied so far. Therefore, the identification of cancer-related piRNAs and the assessment of target genes of piRNAs may lead to better cancer prevention and therapy strategies. This review articleaimed to highlight the role and function of piRNAs based on existing data. Understanding the role of piRNA in cancer may provide perspectives on their applications as particular biomarker signature in diagnosis in early stage, prognosis and therapeutic strategies.

The microRNA-451a/chromosome segregation 1-like axis suppresses cell proliferation, migration, and invasion and induces apoptosis in nasopharyngeal carcinoma

MicroRNA-451a (miR-451a) has been implicated in the initiation and progression of multiple cancers. However, the regulatory mechanisms underlying its function in nasopharyngeal carcinoma (NPC) are poorly understood. Thus, we investigated in detail the role of the microRNA-451a/chromosome segregation 1-like (miR-45a/CSE1L) axis and its regulatory mechanism in NPC. We examined the levels of miR-451a and CSE1L in NPC, and assessed the effects of miR-451a and CSE1L on NPC by cell functional experiments. Furthermore, we elucidated the direct regulatory effect of miR-451a on CSE1L by the luciferase reporter assay, RNA pull-down assay, and RNA immunoprecipitation and validated our observations by calculating the Pearson's correlation coefficient. We found that miR-451a was down-regulated in NPC cells, and its over-expression attenuated cell proliferation, migration, and invasion, and tumor growth in 5-8 F and SUNE-1 cells and promoted apoptosis. Moreover, CSE1L was the direct gene target of miR-451a, and its over-expression abrogated miR-451a-dependent inhibition of malignancy in 5-8 F and SUNE-1 cells. The Pearson's correlation coefficient indicated a negative correlation between CSE1L and miR-451a. miR-451a serves as a tumor suppressor and targets CSE1L. miR-451a suppresses CSE1L expression, thereby reducing proliferation, invasion, and migration and increasing apoptosis of NPC cells.

Gentiopicroside inhibits proliferation, migration, and invasion of gastric cancer HGC-27 cells by regulating miR-34c-5p/XBP1 axis

BACKGROUND

Gentiopicroside (GPS) is a monomer compound of iridoid glycoside, which can inhibit the malignant behavior of lung cancer and ovarian cancer cells, but it is unknown whether it can inhibit the malignant behavior of gastric cancer cells. We hypothesized that GPS could inhibit the malignant behavior of gastric cancer cells by regulating the microRNA-34c-5p(miR-34c-5p)/X-box binding protein-1 (XBP1) axis.

AIM

To explore the effect of GPS on the proliferation, migration, and invasion of gastric cancer cells HGC-27 and the possible mechanism.

METHODS

HGC-27 cells were cultured in vitro and divided into a control group, low-, medium-, and high-dose GPS groups (6, 30, and 150 μg/mL, respectively), a miR-34c-5p group, a miR-NC group, a 150 μg/mL GPS + anti-miR-34c-5p group, and a 150 μg/mL GPS + anti-miR-NC group. Cell counting kit-8 (CCK-8) method was used to detect cell proliferation; cell migration and invasion were detected by Transwell assay; real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the expression of miR-34c-5p. The expression of XBP1 protein in cells was detected by Western blot. The dual luciferase reporter gene assay was used to verify the targeted relationship between miR-34c-5p and XBP1.

RESULTS

Compared with the control group, the cell viability, the number of migrated cells, the number of invaded cells, and the expression of XBP1 protein in the GPS groups (6, 30, and 150 μg/mL) were significantly reduced (P < 0.05), but the expression of miR-34c-5p was significantly increased (P < 0.05). The cell viability, the number of migrated cells, the number of invaded cells, and the expression of XBP1 protein in the miR-34c-5p group were significantly lower than those in the control group and miR-NC group (P < 0.05). miR-34c-5p could regulate the expression of XBP1. Compared with the 150 μg/mL GPS group or 150 μg/mL GPS + anti-miR-NC group, the viability of HGC-27 cells, the number of migrated cells, the number of invaded cells, and the expression of XBP1 protein in the 150 μg/mL GPS + anti-miR-34c-5p group were significantly increased (P < 0.05).

CONCLUSION

Gentiopicroside inhibits the proliferation, migration, and invasion of gastric cancer cells via mechanisms that may be related to the regulation of the miR-34c-5p/XBP1 axis.

Baicalin exerts anti-tumor effects in oral squamous cell carcinoma by inhibiting the microRNA-106b-5p-Wnt/β-catenin pathway via upregulating disabled homolog 2

OBJECTIVE

The aim of this study was to investigate the role and molecular regulatory mechanisms of baicalin in oral squamous cell carcinoma (OSCC) progression.

DESIGN

Gene expression in OSCC cells was detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR). OSCC cell viability, migration, invasion and stemness were measured by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), wound healing, Transwell, and sphere formation assays. The target genes of miR-106b-5p were predicted using bioinformatic tools. The interaction between microRNA-miR-106b-5p (miR-106b-5p) and disabled homolog 2 (DAB2) was confirmed by a luciferase reporter assay. TOP/FOP-Flash reporter assay and western blot analysis were used to analyze the activity of the Wnt/β-catenin pathway.

RESULTS

Baicalin inhibited OSCC cell viability, migration, invasion, and stemness. Baicalin downregulated miR-106b-5p expression. In addition, MiR-106b-5p upregulation reversed the effects of baicalin on OSCC cells. As a target gene of miR-106b-5p, DAB2 was negatively regulated by miR-106b-5p and upregulated by baicalin in OSCC cells. MiR-106b-5p activated Wnt/β-catenin pathway in OSCC cells by inhibiting DAB2. Baicalin suppressed Wnt/β-catenin pathway by upregulating DAB2. In rescue assays, miR-106b-5p overexpression-induced promotion of OSCC cellular processes was attenuated by DAB2 upregulation.

CONCLUSIONS

Baicalin exerts anti-tumor effects in OSCC by inhibiting the miR-106b-5p-Wnt/β-catenin pathway via upregulating DAB2.

MicroRNA-30b-5p promotes the proliferation and migration of human airway smooth muscle cells induced by platelet-derived growth factor by targeting phosphatase and tensin homolog deleted on chromosome ten

Dysfunction of airway smooth muscle (ASM) cells is crucial in asthma pathogenesis. Here, microRNA-30b-5p (miR-30b-5p)’s function and mechanism in ASM cells’ multiplication and migration were investigated. Microarray was utilized for identifying the differentially expressed miRNAs in the bronchial epithelial cells of the asthma patients and healthy controls. Platelet-derived growth factor (PDGF) was employed to treat ASM cells to establish an in-vitro asthma model. Quantitative real-time PCR (qRT-PCR) was conducted for detecting the expressions of miR-30b-5p and phosphatase and tensin homolog deleted on chromosome 10 (PTEN). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 5-bromo-2ʹ-deoxyuridine (BrdU) assays were used for examining cell multiplication; Transwell assay was performed for detecting cell migration; cell cycle was analyzed through flow cytometry. The targeted relationship between PTEN and miR-30b-5p was verified using a dual-luciferase reporter gene assay. Western blot was used for detecting the expressions of phosphorylated (p)-phosphatidylinositol 3-kinase (PI3K), PTEN, PI3K, protein kinase B (AKT) and p-AKT in ASM cells. We demonstrated that, miR-30b-5p expression in the bronchial epithelial cells of asthmatic patients was up-regulated. It was also increased in PDGF-stimulated ASM cells. Transfection of miR-30b-5p mimics facilitated ASM cells’ multiplication, migration and cycle progression, while inhibiting miR-30b-5p had the opposite effect. Furthermore, miR-30b-5p could target PTEN to repress PTEN expression. PTEN overexpression attenuated the effect of miR-30b-5p on ASM cells. Moreover, miR-30b-5p overexpression facilitated the expression of p-PI3K and p-AKT in PDGF-stimulated ASM cells. Collectively, miR-30b-5p activates the PI3K/AKT pathway by targeting PTEN to facilitate PDGF-induced dysfunction of ASM cells.

Long non-coding RNA LINC00511 regulates the expression of microRNA-625-5p and activates signal transducers and activators of transcription 3 (STAT3) to accelerate the progression of gastric cancer

This study aimed to investigate the expression, biological function, and downstream mechanism of LINC00511 in gastric cancer (GC). In paired GC samples, LINC00511, miR-625-5p and STAT3 mRNA expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR); STAT3 protein expression was detected by immunohistochemical (IHC). The gain-of-function and loss-of-function models were established, and the proliferative and migrative ability of GC cells were measured by CCK-8 and transwell assays, respectively. The regulatory relationship between miR-625-5p and LINC00511 or STAT3 was examined by bioinformatics analysis, luciferase reporter gene assay, qRT-PCR, and western blot. We reported that LINC00511 and STAT3 expressions in GC tissues and cell lines were observably up-regulated, while miR-625-5p expression was inhibited. High expression of LINC00511 could facilitate the proliferation and promote the migration of GC cells. miR-625-5p was proved to be a downstream target of LINC00511, and LINC00511 could induce the expression of STAT3 by inhibiting the expression of miR-625-5p. Additionally, knockdown of LINC00511 suppressed the growth and lung metastases of CRC cells in nude mice. In conclusion, LINC00511 promotes the GC cell proliferation and migration via targeting the miR-625-5p/STAT3 axis, implying that LINC00511 can function as a target for GC therapy.