Snail-regulated MiR-375 inhibits migration and invasion of gastric cancer cells by targeting JAK2

MiRNA-766-3p inhibits gastric cancer via targeting COL1A1 and regulating PI3K/AKT signaling pathway

Objective MiRNA-766-3p has been shown to be associated with a variety of cancers. However, few studies have been done in gastric cancer (GC). This study explores the mechanism of miR-766-3p in GC. Methods The potential targets of microRNA (miRNA) were predicted using Tarbase and Targetscan databases. The results are intersected with differential genes (DEGs) (fold change > 1.5, P < 0.05) in gastric cancer to obtain potential core targets. The hub targets screened by constructing PPI networks (degree > 5, expression > 0.5). Validating the differential expression and expression in immunohistochemistry of these targets through the database. And the binding sites between miRNAs and mRNAs were verified using dual-luciferase Assay. Finally, qRT-PCR and Western Blot experiments were conducted to validate the hub targets and signal pathways. Results The potential hub targets from the PPI network were THBS2, COL1A1, FGG, FGB, and PLAU. Combining database, luciferase Assay and experimental validation, miR-766-3p can sponge COL1A1 and it plays the most important role in gastric cancer progression. In GC, COL1A1 was upregulated and the enrichment analysis revealed that COL1A1 regulates PI3K/AKT signal pathway, and AKT is also highly expressed in gastric cancer. Conclusion The miR-766-3p can inhibit the progression of gastric cancer by targeting COL1A1 and regulating the PI3K/AKT signal pathway. It could be a potential therapy option for the GC.

Deregulation of miR-375 Inhibits HOXA5 and Promotes Migration, Invasion, and Cell Proliferation in Breast Cancer

Breast cancer (BC) is a highly aggressive tumour and one of the women's leading causes of cancer-related deaths in worldwide. MiR-375 overexpressed in BC cells, and its biological relevance is largely unknown. Here in, we explored the function of miR-375 in BC. MicroRNA-375 targets were predicted by online target prediction tools and found that HOXA5 is one of the potential targets. MTT assay was employed to assess the effect of miR-375 on cell proliferation, where migration and invasion transwell assays were applied to detect cell migratory and invasive ability. Besides, relative expression of miR-375 and HOXA5 was measured in BC and HEK-293 cells, and its downstream gene target expressions were evaluated by qRT-PCR and western blot. In this study, we found that miR-375 expression was higher in BC cell lines than in the HEK-293 cell line, whereas HOXA5 expression was significantly lower. Our study showed that exogenous inhibition of miR-375 promoted HOXA5 expression; on the contrary, miR-375 mimics down-regulated HOXA5 expression level. Knockdown of miR-375 expression in BC cells reduces cell proliferation, migration, and invasion by inverse correlation expression of HOXA5. Our findings associated that miR-375 accelerated apoptosis evasion, proliferation, migration, and invasion by targeting HOXA5. In addition, nucleolin interferes in miR-375 biogenesis while silencing of nucleolin significantly reduced miR-375 expression and increased HOXA5 expression in BC. Thus, miR-375/HOXA5 axis may represent a potential therapeutic target for BC treatment.

Epi-miRNAs: Regulators of the Histone Modification Machinery in Human Cancer

Cancer is a leading cause of death and disability worldwide. Epigenetic deregulation is one of the most critical mechanisms in carcinogenesis and can be classified into effects on DNA methylation and histone modification. MicroRNAs are small noncoding RNAs involved in fine-tuning their target genes after transcription. Various microRNAs control the expression of histone modifiers and are involved in a variety of cancers. Therefore, overexpression or downregulation of microRNAs can alter cell fate and cause malignancies. In this review, we discuss the role of microRNAs in regulating the histone modification machinery in various cancers, with a focus on the histone-modifying enzymes such as acetylases, deacetylases, methyltransferases, demethylases, kinases, phosphatases, desumoylases, ubiquitinases, and deubiquitinases. Understanding of microRNA-related aberrations underlying histone modifiers in pathogenesis of different cancers can help identify novel therapeutic targets or early detection approaches that allow better management of patients or monitoring of treatment response.

Long noncoding RNA TTTY15 promotes growth and metastasis of esophageal squamous cell carcinoma by sponging microRNA-337-3p to upregulate the expression of JAK2

Long noncoding RNA (lncRNA) testis-specific transcript, Y-linked 15 (TTTY15) plays an important regulatory role in prostate cancer, but its role in esophageal squamous cell carcinoma (ESCC) remains unclear. This study aimed to explore the expression pattern, biological function and underlying mechanism of TTTY15 in ESCC. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of TTTY15 and microRNA (miR)-337-3p in ESCC tissues and cell lines. Cell counting kit-8 method was used to detect the proliferation of ESCC cells. Transwell method was used to determine the migration and invasion of ESCC cells. Luciferase reporter assay was used to verify the interaction between TTTY15 and miR-337-3p. Western blot was used to analyze the effects of TTTY15 and miR-337-3p on Janus kinase 2 (JAK2) expression. In the present study, we demonstrated that the expression level of TTTY15 was significantly upregulated in ESCC tissues, while the expression of miR-337-3p was downregulated. In ESCC samples, the expression levels of TTTY15 and miR-337-3p were negatively correlated. TTTY15 knockdown could significantly reduce the proliferation, migration and invasion of ESCC cells, and miR-337-3p mimics had similar effects. In addition, overexpression of TTTY15 inhibited miR-337-3p by binding with it. TTTY15 could indirectly modulate JAK2, and overexpression of TTTY15 could reverse the inhibitory effects of miR-337-3p on malignant phenotypes of ESCC cells. In conclusion, TTTY15 plays an oncogenic role in ESCC by targeting miR-337-3p/JAK2 axis.

MicroRNA as an Important Target for Anticancer Drug Development

Cancer has become the second greatest cause of death worldwide. Although there are several different classes of anticancer drugs that are available in clinic, some tough issues like side-effects and low efficacy still need to dissolve. Therefore, there remains an urgent need to discover and develop more effective anticancer drugs. MicroRNAs (miRNAs) are a class of small endogenous non-coding RNAs that regulate gene expression by inhibiting mRNA translation or reducing the stability of mRNA. An abnormal miRNA expression profile was found to exist widely in cancer cell, which induces limitless replicative potential and evading apoptosis. MiRNAs function as oncogenes (oncomiRs) or tumor suppressors during tumor development and progression. It was shown that regulation of specific miRNA alterations using miRNA mimics or antagomirs can normalize the gene regulatory network and signaling pathways, and reverse the phenotypes in cancer cells. The miRNA hence provides an attractive target for anticancer drug development. In this review, we will summarize the latest publications on the role of miRNA in anticancer therapeutics and briefly describe the relationship between abnormal miRNAs and tumorigenesis. The potential of miRNA-based therapeutics for anticancer treatment has been critically discussed. And the current strategies in designing miRNA targeting therapeutics are described in detail. Finally, the current challenges and future perspectives of miRNA-based therapy are conferred.

MiR-375 reduces the stemness of gastric cancer cells through triggering ferroptosis

BACKGROUND

Gastric cancer stem cells (CSCs) are the main causes of metastasis and drug resistance. We previously indicated that miR-375 can inhibit Helicobacter pylori-induced gastric carcinogenesis; here, we aim to explore the effects and mechanisms of miR-375 on gastric cancer (GC) cell stemness.

METHODS

Lentivirus infection was used to construct GC cells with ectopic expression of miR-375. In vitro and in vivo experiments, including analysis of tumor spheroid formation, CD44+ sub-population with stemness, stemness marker expression, and tumor-initiating ability, were performed to evaluate the effects of miR-375 on the stemness of GC cells. Furthermore, microarray and bioinformatics analysis were performed to search the potential targets of miR-375 in GC cells. Luciferase reporter, RNA immunoprecipitation, and RNA-FISH assays were carried out to verify the targeting of miR-375. Subsequently, combined with tissue microarray analysis, erastin-resistant GC cells, transmission electron microscopy, a series of agonists and oxidative stress markers, the underlying mechanisms contributing to miR-375-mediated effects were explored.

RESULTS

MiR-375 reduced the stemness of GC cells in vitro and in vivo. Mechanistically, SLC7A11 was identified as a direct target of miR-375 and miR-375 attenuated the stemness of GC cells mainly through triggering SLC7A11-dependent ferroptosis.

CONCLUSION

MiR-375 can trigger the ferroptosis through targeting SLC7A11, which is essential for miR-375-mediated inhibition on GC cell stemness. These results suggest that the miR-375/SLC7A11 regulatory axis could serve as a potential target to provoke the ferroptosis and thus attenuate the stemness of GC cells.

MicroRNA Changes in Gastric Carcinogenesis: Differential Dysregulation during Helicobacter pylori and EBV Infection

Despite medical advances, gastric-cancer (GC) mortality remains high in Europe. Bacterial infection with Helicobacter pylori (H. pylori) and viral infection with the Epstein–Barr virus (EBV) are associated with the development of both distal and proximal gastric cancer. Therefore, the detection of these infections and the prediction of further cancer development could be clinically significant. To this end, microRNAs (miRNAs) could serve as promising new tools. MiRNAs are highly conserved noncoding RNAs that play an important role in gene silencing, mainly acting via translational repression and the degradation of mRNA targets. Recent reports demonstrate the downregulation of numerous miRNAs in GC, especially miR-22, miR-145, miR-206, miR-375, and miR-490, and these changes seem to promote cancer-cell invasion and tumor spreading. The dysregulation of miR-106b, miR-146a, miR-155, and the Let-7b/c complex seems to be of particular importance during H. pylori infection or gastric carcinogenesis. In contrast, many reports describe changes in host miRNA expression and outline the effects of bamHI-A region rightward transcript (BART) miRNA in EBV-infected tissue. The differential regulation of these miRNA, acting alone or in close interaction when both infections coexist, may therefore enable us to detect cancer earlier. In this review, we focus on the two different etiologies of gastric cancer and outline the molecular pathways through which H. pylori- or EBV-induced changes might synergistically act via miR-155 dysregulation to potentiate cancer risk. The three markers, namely, H. pylori presence, EBV infection, and miR-155 expression, may be checked in routine biopsies to evaluate the risk of developing gastric cancer.

Long non-coding RNA SNHG6 increases JAK2 expression by targeting the miR-181 family to promote colorectal cancer cell proliferation

BACKGROUND

Long non-coding RNA (lncRNA) small nucleolar RNA host gene 6 (SNHG6) exerts a regulatory role in cancer biology, although its detailed functions and mechanisms in colorectal cancer (CRC) still remain unclear.

METHODS

A quantitative reverse transcriptase-polymerase chain reaction was implemented to investigate the expression of SNHG6, miR-181 family and Janus kinase 2 (JAK2) in CRC tissues and cell lines. The proliferation of CRC cells was detected by a cell counting kit-8 assay, and the apoptosis of CRC cells was determined by flow cytometry analysis. The interaction of the miR-181 family with SNHG6 or with the 3'-untranslated region of JAK2 was validated by the luciferase reporter gene method. The effects of SNHG6 and the miR-181 family on JAK2 expression were analyzed by western blotting.

RESULTS

SNHG6 was significantly up-regulated in CRC samples. The knockdown of SNHG6 reduced the proliferation of CRC cells and promoted the apoptosis, whereas the over-expression of SNHG6 had the opposite effect. SNHG6 could bind with all the four members of the miR-181 family, and expression in miR-181 family members was significantly down-regulated in CRC samples. SNHG6 expression was negatively correlated with the miR-181 family member expression in CRC samples. Moreover, over-expressed SNHG6 significantly counteracted the inhibitory effect of miR-181 mimics on CRC cell proliferation, as well as the promoting effect on apoptosis. Furthermore, SNHG6 over-expression and knockdown can promote and inhibit JAK2 expression, respectively, and miR-181 family member function is opposite to that of SNHG6 by repressing JAK2.

CONCLUSIONS

SNHG6 can exert a cancer-promoting effect in CRC by targeting miR-181 family members and up-regulating JAK2.

The regulatory mechanism and biological significance of the Snail-miR590-VEGFR-NRP1 axis in the angiogenesis, growth and metastasis of gastric cancer

Vascular endothelial growth factor receptor (VEGFR) and neuropilins (NRPs), a co-receptor of VEGF, play a key role in the formation and development of blood vessels and in tumour growth and metastasis. However, whether VEGFR1/2 and NRP1 are regulated by the same upstream mechanism is unclear, especially in gastric cancer. We used prediction tools to detect miRNAs that may simultaneously regulate VEGFR1/2 and NRP1, and we finally determined that miR-590 can simultaneously regulate VEGFR1/2 and NRP1 in gastric cancer. We discovered that miR-590 was downregulated in gastric cancer tissues and cell lines, and this was related to the dysregulation of the transcription factor SNAIL. In addition, the overexpression of miR-590 inhibits the migration, invasion, proliferation and D-MVA levels of gastric cancer cells in vivo and in vitro by targeting VEGFR1/2 and NRP1. We also demonstrated that miR-590 may be a useful marker for the prognosis of gastric cancer with Kaplan–Meier survival analysis. Since the epithelial-to-mesenchymal transition (EMT) is an important mechanism of tumour invasion and metastasis and VEGFR1/2 and NRP1 can promote the occurrence of EMT, we speculated that miR-590 can regulate the occurrence of EMT. Immunoblot and immunofluorescence analyses confirmed that the overexpression of miR-590 can inhibit the EMT in gastric cancer cells. Since SNAIL is also a mesenchymal marker, our results revealed a new, positive feedback loop. As a transcription factor, SNAIL inhibits the expression of miR-590, thereby upregulating the expression levels of NRP1 and VEGFR1/2; this leads to the development of EMT in gastric cancer and the upregulation of SNAIL.

MicroRNA (miR) dysregulation during Helicobacter pylori-induced gastric inflammation and cancer development: critical importance of miR-155

Dysregulation of noncoding microRNA molecules has been associated with immune cell activation in the context of Helicobacter pylori induced gastric inflammation as well as carcinogenesis, but also with downregulation of mismatch repair genes, and may interfere with immune checkpoint proteins that lead to the overexpression of antigens on gastric tumor cells. Numerous miR-molecules have been described as important tools and markers in gastric inflammation and cancer development -including miR-21, miR-143, miR-145, miR-201, and miR-335- all of which are downregulated in gastric tumors, and involved in cell cycle growth or tumor invasion. Among the many microRNAs involved in gastric inflammation, adenocarcinoma development and immune checkpoint regulation, miR-155 is notable in that its upregulation is considered a key marker of chronic gastric inflammation that predisposes a patient to gastric carcinogenesis. Among various other miRs, miR-155 is highly expressed in activated B and T cells and in monocytes/macrophages present in chronic gastric inflammation. Notably, miR-155 was shown to downregulate the expression of certain MMR genes, such as MLH1, MSH2, and MSH6. In tumor-infiltrating miR-155-deficient CD8⁺ T cells, antibodies against immune checkpoint proteins restored the expression of several derepressed miR-155 targets, suggesting that miR-155 may regulate overlapping pathways to promote antitumor immunity. It may thus be of high clinical impact that gastric pathologies mediated by miR-155 result from its overexpression. This suggests that it may be possible to therapeutically attenuate miR-155 levels for gastric cancer treatment and/or to prevent the progression of chronic gastric inflammation into cancer.

Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.

The Role of MicroRNAs upon Epithelial-to-Mesenchymal Transition in Inflammatory Bowel Disease

Increasing evidence suggest the significance of inflammation in the progression of cancer, for example the development of colorectal cancer in Inflammatory Bowel Disease (IBD) patients. Long-lasting inflammation in the gastrointestinal tract causes serious systemic complications and breaks the homeostasis of the intestine, where the altered expression of regulatory genes and miRNAs trigger malignant transformations. Several steps lead from acute inflammation to malignancies: epithelial-to-mesenchymal transition (EMT) and inhibitory microRNAs (miRNAs) are known factors during multistage carcinogenesis and IBD pathogenesis. In this review, we outline the interactions between EMT components and miRNAs that may affect cancer development during IBD.

Decreased expression of serum miR-647 is associated with poor prognosis in gastric cancer

MicroRNAs (miRNAs) have been demonstrated to be critical players in different types of tumors including gastric cancer (GC). However, the expression level of serum miR-647 in patients with GC and its potential prognostic significance were poorly known. The aim of this study was to investigate the clinical significance of serum miR-647 in GC. A total of 105 patients with GC and 50 healthy volunteers were recruited into this study. Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) was used to analyze the expression of serum miR-647. Diagnostic accuracy of serum miR-647 in distinguishing GC patients from healthy controls was assessed by the receiver operating characteristic (ROC) curve analysis. Chi-square was used to evaluate the association between serum miR-647 level and clinicopathologic parameters. Kaplan-Meier method was used to analyze the overall survival (OS) and relapse-free survival (RFS). Multivariate Cox proportional hazards analyses were further used to identify prognostic factors. Our results showed that a significantly downregulated expression of serum miR-647 was found in patients with GC. ROC curve analyses showed that serum miR-647 was highly efficient for discriminating patients with GC from healthy controls. In addition, low serum miR-647 expression was associated with aggressive clinical features and unfavorable survival in GC. Mechanistically downregulation of miR-647 in GC cell lines increased the expression levels of STX6, STX7, and PRKCA. In conclusion, our results demonstrate that serum miR-647 might serve as a novel serum biomarker for monitoring GC progression.

Magnesium isoglycyrrhizinate ameliorates high fructose-induced liver fibrosis in rat by increasing miR-375-3p to suppress JAK2/STAT3 pathway and TGF-β1/Smad signaling

Increasing evidence has demonstrated that excessive fructose intake induces liver fibrosis. Epithelial-mesenchymal transition (EMT) driven by transforming growth factor-β1 (TGF-β1)/mothers against decapentaplegic homolog (Smad) signaling activation promotes the occurrence and development of liver fibrosis. Magnesium isoglycyrrhizinate is clinically used as a hepatoprotective agent to treat liver fibrosis, but its underlying molecular mechanism has not been identified. Using a rat model, we found that high fructose intake reduced microRNA (miR)-375-3p expression and activated the janus-activating kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) cascade and TGF-β1/Smad signaling, which is consistent with the EMT and liver fibrosis. To further verify these observations, BRL-3A cells and/or primary rat hepatocytes were exposed to high fructose and/or transfected with a miR-375-3p mimic or inhibitor or treated with a JAK2 inhibitor, and we found that the low expression of miR-375-3p could induce the JAK2/STAT3 pathway to activate TGF-β1/Smad signaling and promote the EMT. Magnesium isoglycyrrhizinate was found to ameliorate high fructose-induced EMT and liver fibrosis in rats. More importantly, magnesium isoglycyrrhizinate increased miR-375-3p expression to suppress the JAK2/STAT3 pathway and TGF-β1/Smad signaling in these animal and cell models. This study provides evidence showing that magnesium isoglycyrrhizinate attenuates liver fibrosis associated with a high fructose diet.

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

Objectives

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

Materials and methods

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

Results

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

Conclusions

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

Deregulation of MicroRNA-375 Inhibits Proliferation and Migration in Gastric Cancer in Association With Autophagy-Mediated AKT/mTOR Signaling Pathways

Gastric cancer is a deadly disease. Some microRNAs are involved in tumor invasion and metastasis. Underexpression of miR-375 has been correlated with tumorigenesis, treatment resistance, and poor prognosis. In this study, we first analyzed the profiles and prognostic values of miR-375 expression in gastric cancer tissues from a public database, and the expression level of miR-375 in gastric cancer samples and gastric cancer cell lines was then analyzed by quantitative real- time polymerase chain reaction. Significant underexpression of miR-375 was seen in all the gastric cancer samples compared to paired paracarcinoma tissues, and the expression level of miR-375 in the gastric cancer cell lines was negatively associated with the cell migration ability. A Cell proliferation (CCK-8) assay was performed to examine cell viability. Overexpression of miR-375 suppressed the proliferation of gastric cancer cells. A Western blot analysis was carried out to test protein expression. Overexpression of miR-375 inhibited autophagy through the AKT/ mammalian target of rapamycin signaling pathway. MiR-375 regulated invasion and migration via AKT/ mammalian target of rapamycin pathway-mediated epithelial-to-mesenchymal transition. Wound healing and migration assays were used to determine the motility of gastric cancer cells. A gastric cancer xenograft nude mouse model was used for an in vivo efficacy evaluation. Overexpression of miR-375 significantly suppressed cell proliferation in the established gastric cancer xenograft nude mouse model. Our results demonstrate that increasing the expression level of miR-375 suppresses proliferation in vitro and in vivo, and they provide a mechanistic and applicable rationale for the future clinical evaluation of miR-375 in gastric cancer treatment. Our findings provide not only new information about the molecular mechanism of microRNAs in regulating invasion and migration in gastric cancer but also a theoretical principle for a potential targeted therapy for gastric cancer.

MiR-133 inhibits cell proliferation, migration, and invasion in gastric cancer cells by targeting JAK2

AIM

To investigate the role of miR-133 in the proliferation, migration, and invasion of gastric cancer (GC) cells, and to explore the underlying mechanism.

METHODS

The expression of miR-133 and JAK2 mRNA in tissues and cells was detected by qRT-PCR. AGS and MGC-803 cells were transfected with miR-133 mimic (miR-133 group), miR-133 inhibitor (miR-133 inhibitor group), nonspecific inhibitor (inhibitor-NC group), psiCHECK2-JAK2-3 UTR WT vector and miR-133 mimic (JAK2 WT group), psiCHECK2-JAK2-3 UTR MUT vector and miR-133 mimic (JAK2 MUT group), miR-133 mimic and JAK2 (miR-133 + JAK2 group), or miR-133 mimic and pc-DNA 3.1 (miR-133 + vector group) using a liposome-mediated method. Untransfected cells (miR-NC group) were also included as a control. The protein expression of JAK2 was detected by Western blot. Cell proliferation was detected by MTT assay. Cell migration and invasion were detected by Transwell assay. The luciferase activity was detected by double luciferase reporter assay.

RESULTS

Compared with human paracancerous tissues or normal gastric mucosal cells (GES-1), miR-133 was down-regulated in GC tissues and GC cells (AGS and MGC-803), and JAK2 was highly expressed in GC tissues and AGS and MGC-803 cells (P < 0.05). Overexpression of miR-133 or silencing JAK2 could inhibit cell proliferation, migration, and invasion in GC cells. JAK2 is a target of miR-133, and JAK2 could rescue the inhibitory effect of miR-133 on cell proliferation, migration, and invasion in GC cells.

CONCLUSION

MiR-133 could inhibit the proliferation, migration, and invasion of GC cells via mechanisms possibly related to targeting of JAK2, which will provide a new target for the clinical diagnosis and treatment of GC.

The biological functions of target genes in pan-cancers and cell lines were predicted by miR-375 microarray data from GEO database and bioinformatics

BACKGROUND

MicroRNA is endogenous non-coding small RNA that negative regulate and control gene expression, and increasing evidence links microRNA to oncogenesis and the pathogenesis of cancer. The goal of this study was to explore the potential molecular mechanism of miR-375 in various cancers.

METHODS

MiR-375 overexpression in different tumor cell lines was probed with microarray data from Gene Expression Omnibus (GEO). The common target genes of miR-375 were obtained by Robust Rank Aggregation (RRA), and identified by miRWalk2.0 software for target gene prediction. Additionally, we directed in silico analysis including Protein-Protein Interactions (PPI) analysis, gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways annotations to provide a summary of the function of miR-375 in various carcinomas. Eventually, data was obtained from The Cancer Genome Atlas (TCGA) were utilized for a validation in 7 cancers.

RESULTS

The nine miR-375 related chips were acquired by the GEO data. The 5 down regulated genes came from 9 available microarray datasets, which overlapped with the potential target genes predicted by miRWalk2.0 software. The target genes were intensely enriched in amino acid biosynthetic and metabolic process from biological process (GO) and Cysteine and methionine metabolism (KEGG analysis). In view of these approaches, VASN, MAT2B, HERPUD1, TPAPPC6B and TAT are probably the most important miR-375 targets. In addition, miR-375 was negatively correlated with MAT2B, which was verified in 5 tumors of TCGA.

CONCLUSION

In summary, this study based on common target genes provides an innovative perspective for exploring the molecular mechanism of miR-375 in human tumors.

MicroRNA Expression Profiles in Gastric Carcinogenesis

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

Novel serum microRNAs panel on the diagnostic and prognostic implications of hepatocellular carcinoma

AIM

To determine a panel of serum microRNAs (miRNAs) that could be used as novel biomarkers for diagnosis of hepatocellular carcinoma (HCC).

METHODS

We initially screened 9 out of 754 serum miRNAs by TaqMan Low Density Array in two pooled samples respectively from 35 HCC and 35 normal controls, and then validated individually by RT-qPCR in another 114 patients and 114 controls arranged in two phases. The changes of the selected miRNAs after operation and their prognostic value were examined.

RESULTS

miR-375, miR-10a, miR-122 and miR-423 were found to be significantly higher in HCC than in controls (P < 0.0001), and the area under the receiver-operating-characteristic curve for the 4-miRNA panel was 0.995 (95%CI: 0.985-1). All the four miRNAs were significantly reduced after surgical removal of the tumors (P < 0.0001), while still higher than normal controls (at least P < 0.05)

CONCLUSION

The four serum miRNAs (miR-375, miR-10a, miR-122 and miR-423) could potentially serve as novel biomarkers for the diagnostic and prognostic of HCC.

The SNAIL/miR-128 axis regulated growth, invasion, metastasis, and epithelial-to-mesenchymal transition of gastric cancer

miR-128 is expressed in various tumors, but its expression and function in gastric cancer have not been defined. Thus, the goal of this study was to characterize miR-128 in gastric cancer. We found first that miR-128 is down-regulated in gastric cancer cell lines and tissues, and this dysregulation is correlated with DNA methylation and the transcription factor SNAIL. Using prediction tools, western blotting, and luciferase reporter assays, we found that Bmi-1 was the direct target of miR-128. Additionally, overexpression of miR-128 inhibited gastric cancer cell migration, invasion, and proliferation by targeting Bmi-1 in vitro and in vivo. We also documented, with receiver operating characteristic curves and Kaplan-Meier survival analysis, that miR-128 and Bmi-1 may be useful markers for diagnosing and estimating the prognosis of gastric cancer patients. As the epithelial-to-mesenchymal transition is an important mechanism associated with cancer invasion and metastasis, we inferred that miR-128 could regulate this mechanism in gastric cancer. In fact, we found that miR-128 could reverse epithelial-to-mesenchymal transition induced by Bmi-1 via the PI3K/AKT pathway. Because SNAIL also acts as a mesenchymal marker, our findings identified a novel positive feedback loop in which the transcription factor SNAIL curbs the expression of miR-128, and then down-regulated miR-128 promotes the expression of Bmi-1; finally, overexpression of Bmi-1 drives the epithelial-to-mesenchymal transition process via the PI3K/AKT pathway, and the expression of SNAIL is up-regulated.

MicroRNA-28-5p inhibits the migration and invasion of gastric cancer cells by suppressing AKT phosphorylation

Gastric cancer is a polygenic disease with a high mortality rate worldwide. Although a number of dysregulated genes have been confirmed to be involved in development and progression of gastric cancer, the molecular mechanisms by which this occurs remain unclear. The present study identified that microRNA (miR-28-5p) was involved in the migration and invasion of gastric cancer cells, and was able to affect the prognosis of patients with gastric cancer. Reverse transcription-quantitative polymerase chain reaction analysis indicated that the expression of miR-28-5p was significantly downregulated in gastric cancer tissues, and that patients with higher expression had a good prognosis. miR-28-5p expression was significantly associated with depth of invasion, lymph node metastasis and pathological stage. Gastric cancer cells overexpressing miR-28-5p exhibited a marked reduction of migration and invasion by Transwell and wound scratch assay. The phosphorylation of RAC serine/threonine-protein kinase (AKT), which affected cellular invasion and metastasis, was significantly inhibited by overexpression of miR-28-5p. In conclusion, miR-28-5p is a tumor suppressor that inhibits gastric cancer cell migration and invasion through repressing AKT phosphorylation. miR-28-5p may therefore represent a potential biomarker for the prognosis of gastric cancer and a novel therapeutic target in advanced gastric cancer.

A novel miR-375-HOXB3-CDCA3/DNMT3B regulatory circuitry contributes to leukemogenesis in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous group of hematopoietic malignancies due to sophisticated genetic mutations and epigenetic dysregulation. MicroRNAs (miRNAs), a class of small non-coding RNAs, are important regulators of gene expression in all biological processes, including leukemogenesis. Recently, miR-375 has been reported to be a suppressive miRNA in multiple types of cancers, but its underlying anti-leukemia activity in AML is largely unknown.

METHODS

Quantitative reverse transcriptase PCR (qRT-PCR) was used to measure the expression of miR-375 and HOXB3 in leukemic cells and normal controls. Targets of miR-375 were confirmed by western blot and luciferase assay. Phenotypic effects of miR-375 overexpression and HOXB3 knockdown were assessed using viability (trypan blue exclusion assay), colony formation/replating, as well as tumor xenograft assays in vivo.

RESULTS

The expression of miR-375 was substantially decreased in leukemic cell lines and primary AML blasts compared with normal controls, because DNA hypermethylation of precursor-miR-375 (pre-miR-375) promoter was discovered in leukemic cells but not in normal controls. Lower expression of miR-375 predicted poor outcome in AML patients. Furthermore, forced expression of miR-375 not only decreased proliferation and colony formation in leukemic cells but also reduced xenograft tumor size and prolonged the survival time in a leukemia xenograft mouse model. Mechanistically, overexpression of miR-375 reduced HOXB3 expression and repressed the activity of a luciferase reporter through binding 3'-untranslated regions (3'-UTR) of HOXB3 mRNA. Overexpression of HOXB3 partially blocked miR-375-induced arrest of proliferation and reduction of colony number, suggesting that HOXB3 plays an important role in miR-375-induced anti-leukemia activity. Knockdown of HOXB3 by short hairpin RNAs reduced the expression of cell division cycle associated 3 (CDCA3), which decreased cell proliferation. Furthermore, HOXB3 induced DNA methyltransferase 3B (DNMT3B) expression to bind in the pre-miR-375 promoter and enhanced DNA hypermethylation of pre-miR-375, leading to the lower expression of miR-375.

CONCLUSIONS

Collectively, we have identified a miR-375-HOXB3-CDCA3/DNMT3B regulatory circuitry which contributes to leukemogenesis and suggests a therapeutic strategy of restoring miR-375 expression in AML.

miR-375 is involved in Hippo pathway by targeting YAP1/TEAD4-CTGF axis in gastric carcinogenesis

miR-375 is a tumor-suppressive microRNA (miRNA) in gastric cancer (GC). However, its molecular mechanism remains unclear. The aim of this study is to comprehensively investigate how miR-375 is involved in Hippo pathway by targeting multiple oncogenes. miR-375 expression in gastric cancer cell lines and primary GC was investigated by qRT-PCR. The regulation of YAP1, TEAD4, and CTGF expression by miR-375 was evaluated by qRT-PCR, western blot, and luciferase reporter assays, respectively. The functional roles of the related genes were examined by siRNA-mediated knockdown or ectopic expression assays. The clinical significance and expression correlation analysis of miR-375, YAP1, and CTGF were performed in primary GCs. TCGA cohort was also used to analyze the expression correlation of YAP1, TEAD4, CTGF, and miR-375 in primary GCs. miR-375 was down-regulated in GC due to promoter methylation and histone deacetylation. miR-375 downregulation was associated with unfavorable outcome and lymph node metastasis. Ectopic expression of miR-375 inhibited tumor growth in vitro and in vivo. Three components of Hippo pathway, YAP1, TEAD4 and CTGF, were revealed to be direct targets of miR-375. The expression of three genes showed a negative correlation with miR-375 expression and YAP1 re-expression partly abolished the tumor-suppressive effect of miR-375. Furthermore, CTGF was confirmed to be the key downstream of Hippo-YAP1 cascade and its knockdown phenocopied siYAP1 or miR-375 overexpression. YAP1 nuclear accumulation was positively correlated with CTGF cytoplasmic expression in primary GC tissues. Verteporfin exerted an anti-oncogenic effect in GC cell lines by quenching CTGF expression through YAP1 degradation. In short, miR-375 was involved in the Hippo pathway by targeting YAP1-TEAD4-CTGF axis and enriched our knowledge on the miRNA dysregulation in gastric tumorigenesis.

Soft-shelled turtle peptide modulates microRNA profile in human gastric cancer AGS cells

Cancer prevention using natural micronutrition on epigenetic mechanisms primarily revolves around plant extracts. However, the role of macronutrition, including animal peptides, on epigenetic modification in cancer has been elusive. In traditional Chinese medicine, the soft-shelled turtle has a long-history of being a functional food that strengthens immunity through unknown mechanisms. The present study aimed to investigate the impact of soft-shelled turtle peptide on microRNA (miRNA) expression in gastric cancer (GC) cells and to analyze the potential anticancer mechanisms for GC. Affymetrix GeneChip miRNA 3.0 Array and quantitative polymerase chain reaction were used to detect the miRNA expression profile in human GC AGS cells treated with the soft-shelled turtle peptide. The results demonstrated that 101 miRNAs (49 upregulated miRNAs and 52 downregulated miRNAs) were significantly differentially expressed in the AGS cells following soft-shelled turtle peptide treatment. Several tumor suppressor miRNAs were upregulated markedly, including miRNA-375, let-7d, miRNA-429, miRNA-148a/148b and miRNA-34a. Pathway analysis indicated that soft-shelled turtle peptide may function with anticancer properties through the Hippo signaling pathway and the forkhead box O signaling pathway. Therefore, these results demonstrated that soft-shelled turtle peptide has the capacity to influence cancer-related pathways through the regulation of miRNA expression in GC cells.

Emblica officinalis extract downregulates pro-angiogenic molecules via upregulation of cellular and exosomal miR-375 in human ovarian cancer cells

Ovarian cancer (OC) is highly resistant to current treatment strategies based on a combination of surgery, chemotherapy and radiation therapy. We have recently demonstrated the anti-neoplastic effect of Amla extract (Emblica officinalis, AE) on OC cells in vitro and in vivo. We hypothesized that AE attenuates growth of OC through microRNA (miR)-regulated mechanism(s). The inhibitory effect of AE on proliferation, migration and invasiveness (P≤0.001) of SKOV3 cells and >90% attenuation of tumor growth in a xenograft mouse model suggested multiple targets. RT-qPCR analysis of microRNAs associated with OC showed a >2,000-fold increase in the expression of miR-375 in AE-treated SKOV3 cells that was blocked by an exogenous miR-375 inhibitor (P≤0.001). AE also decreased the gene and protein expression of IGF1R, a target of miR-375 (P≤0.001), and SNAIL1 (P≤0.002), an EMT-associated transcription factor that represses E-cadherin expression (P≤0.003). AE increased E-cadherin expression (P≤0.001). Treatment of SKOV3 cells with AE resulted in increased miR-375 in exosomes in the medium (P≤0.01). Finally, AE significantly decreased the expression of IGF1R and SNAIL1 proteins during attenuation of SKOV3-derived xenograft tumor. Together, these results show that AE modulates cancer cells and the tumor microenvironment via activation of miR-375 and by targeting IGF1R and SNAIL1 in OC cells.

Overexpression of microRNA-375 impedes platelet-derived growth factor-induced proliferation and migration of human fetal airway smooth muscle cells by targeting Janus kinase 2

The abnormal proliferation and migration of airway smooth muscle (ASM) cells play a critical role in airway remodeling during the development of asthma. MicroRNAs (miRNAs) have emerged as critical regulators of ASM cell proliferation and migration in airway remodeling. In this study, we aimed to investigate the potential role of miR-375 in the regulation of platelet-derived growth factor (PDGF)-induced fetal ASM cell proliferation and migration. Our results showed that miR-375 expression was significantly decreased in fetal ASM cells that were treated with PDGF. Functional data showed that overexpression of miR-375 inhibited the proliferation and migration of fetal ASM cells, whereas inhibition of miR-375 enhanced the proliferation and migration of fetal ASM cells. The results of bioinformatics analysis and a dual-luciferase reporter assay showed that miR-375 binds directly to the 3'-untranslated region of Janus kinase 2 (JAK2). Further data confirmed that miR-375 negatively regulates the expression of JAK2 in fetal ASM cells. Moreover, miR-375 also impeded the PDGF-induced activation of signal transducer and activator of transcription 3 (STAT3) in fetal ASM cells. However, restoration of JAK2 expression partially reversed the inhibitory effect of miR-375 on fetal ASM cell proliferation and migration. Overall, our results demonstrate that miR-375 inhibits fetal ASM cell proliferation and migration by targeting JAK2/STAT3 signaling. Our study provides a potential therapeutic target for the development of novel treatment strategies for pediatric asthma.

Downregulation of microRNA-375, combined with upregulation of its target gene Janus kinase 2, predicts unfavorable prognosis in patients with gastric cancer

MicroRNA (miR)-375 has been reported to function as a tumor suppressor in gastric cancer via targeting Janus kinase 2 (JAK2). Until now, no clinical evidence of miR-375-JAK2 combination in gastric cancer has been documented. Here, quantitative real-time PCR was performed to detect the serum levels of miR-375 and JAK2 mRNA in 100 patients with gastric cancer and 50 healthy controls. Receiver operating characteristic (ROC) analysis was used to assess the predictive diagnostic value of serum miR-375 and/or JAK2 mRNA for gastric cancer. Associations of serum miR-375 and/or JAK2 mRNA levels with various clinicopathological features and prognosis in patients with gastric cancer were also analyzed. As a result, miR-375 expression was significantly downregulated, while JAK2 mRNA expression was dramatically upregulated, in patients' sera of gastric cancer (both P<0.001), compared to healthy controls. Notably, the areas under ROC curve for serum miR-375 and JAK2 discriminating gastric cancer patients from healthy controls were respectively 0.871 (sensitivity = 82.00%, specificity = 72.00%) and 0.864 (sensitivity = 55.00%, specificity = 100.00%). Moreover, miR-375 downregulation and/or JAK2 upregulation were all significantly associated with positive lymph node metastasis, high tumor-node-metastasis stage and the presence of H. pylori infection in patients with gastric cancer (all P<0.05). Furthermore, serum miR-375 and/or JAK2 were all independent prognostic factors for patients with gastric cancer. Importantly, the prognostic value of miR-375-JAK2 combination was more significant than considered alone. Collectively, serum miR-375 and JAK2 combination may be a potential diagnostic and prognostic predictor of gastric cancer. miR-375-JAK2 axis might be a promising candidate for a molecular targeted therapy of this malignancy.

Down-regulated microRNA-375 expression as a predictive biomarker in non-small cell lung cancer brain metastasis and its prognostic significance

Brain metastases (BM) are common among patients with non-small cell lung cancer (NSCLC) and have been associated with significant morbidity and limited survival. Early and sensitive detection of BM is essential for improving prognosis. Recently, microRNA-375(miR-375) which is specifically expressed in the brain has been found significantly dysregulated in many human cancers. However, there is still no data whether miR-375 is associated with higher risk of BM development in NSCLC. In this study, we detected the miR-375 expression using quantitative real-time PCR (qRT-PCR) and assessed its predictive and prognostic significance. Our result showed that miR-375 expression was significantly down-regulated in NSCLC patients with BM(BM+, N=30) compared with NSCLC without BM(BM-, N=30) (P<0.001). Statistical analysis indicated that low miR-375 expression was linked to advanced disease stage (P<0.001) and brain metastasis (P<0.001) in NSCLC patient. Survival analysis suggested that low-expression group had significantly shorter overall survival than high-expression group in NSCLC patients with BM(log-rank test: P<0.05) as well as the total cases(log-rank test: P<0.01). Multivariate Cox proportional hazards model analysis indicated that low miR-375 expression was independently linked to poor survival of patients with NSCLC (HR=5.48, 95% CI: 1.93-15.56, P=0.001). In addition, we found that VEGF and MMP-9 were over-expressed in down-regulated miR-375 expression cases. Collectively, this study demonstrated that miR-375 may play an important role as a predictive biomarker in brain metastasis and an independent prognostic factor in NSCLC. Over-expression of VEGF and MMP-9 may be the reason for poor prognosis of NSCLC patients with low miR-375 expression.

Inhibitors of the PI3K/mTOR pathway prevent STAT5 phosphorylation in JAK2V617F mutated cells through PP2A/CIP2A axis

Inhibition of the constitutively activated JAK/STAT pathway in JAK2V617F mutated cells by the JAK1/JAK2 inhibitor ruxolitinib resulted in clinical benefits in patients with myeloproliferative neoplasms. However, evidence of disease-modifying effects remains scanty; furthermore, some patients do not respond adequately to ruxolitinib, or have transient responses, thus novel treatment strategies are needed. Here we demonstrate that ruxolitinib causes incomplete inhibition of STAT5 in JAK2V617F mutated cells due to persistence of phosphorylated serine residues of STAT5b, that conversely are targeted by PI3K and mTORC1 inhibitors. We found that PI3K/mTOR-dependent phosphorylation of STAT5b serine residues involves Protein Phosphatase 2A and its repressor CIP2A. The levels of CIP2A were found increased in cells harboring the JAK2V617F mutation, and we provide evidence of a correlation between clinical responses and the extent of CIP2A downregulation in myelofibrosis patients receiving the mTOR inhibitor RAD001 in a phase II clinical trial. To achieve maximal inhibition of STAT5 phosphorylation, we combined ruxolitinib with BKM120, a PI3K inhibitor, and RAD001, an mTOR inhibitor, obtaining improved efficacy in JAK2V617F mutated cell lines, primary patients’ cells, and JAK2V617F knock-in mice. These findings contribute to understanding the effectiveness of PI3K/mTOR inhibitors in MPN and argue for the rationale to develop combination clinical trials.

Astaxanthin Inhibits PC-3 Xenograft Prostate Tumor Growth in Nude Mice

Prostate cancer (PCa), the most common malignancy in men, is a major cause of cancer deaths. A better understanding of the mechanisms that drive tumor initiation and progression may identify actionable targets to improve treatment of this patient group. As a dietary carotenoid, astaxanthin has been demonstrated to exert beneficial effects against inflammation, cardiovascular disease, oxidative damage, or different cancer sites. This study used intragastric administration of astaxanthin to detect its role on tumor proliferation, apoptosis, microRNA (miRNA) overexpression, and microbacteria composition change by establishing androgen-independent PCa cell PC-3 xenograft nude mice. Nude mice were inoculated with androgen-independent prostate cancer PC-3 cells subcutaneously. The intervention was started when tumors reached 0.5–0.6 cm in diameter. Mice were intragastrically administered 100 mg/kg astaxanthin (HA), 25 mg/kg astaxanthin (LA), or olive oil (TC). The results showed that 100 mg/kg astaxanthin significantly inhibited tumor growth compared to the TC group, with an inhibitory rate of 41.7%. A decrease of Ki67 and proliferating cell nuclear antigen (PCNA) as well as an increase of cleaved caspase-3 were observed in HA-treated tumors, along with increasing apoptotic cells, obtained by TUNEL assay. The HA significantly elevated the levels of tumor suppressors miR-375 and miR-487b in tumor tissues and the amount of Lactobacillus sp. and Lachnospiraceae in mice stools, while there was no significant difference between LA and TC groups. These results provide a promising regimen to enhance the therapeutic effect in a dietary supplement manner.

MiR-146a suppresses hepatocellular carcinoma by downregulating TRAF6

MicroRNAs have been proven to play important roles in many biological processes such as cellular growth and differentiation, apoptosis, and modulation of host response to viral infection. In the present study, we find that the expression of miR-146a was decreased in hepatocellular carcinoma (HCC) tissues compared with corresponding adjacent tissues, and the expression level in HCC cell lines was lower than in a normal liver cell. Over-expression suppressed the proliferation and invasion of HCC cells. In addition, luciferase reporter assays and western blotting confirmed that miR-146a directly target TRAF6 which attenuated the effect of miR-146a on cell proliferation and invasion in HepG2 and SMMC7721 cells. Meanwhile, lentivirus-mediated increased expression of miR146a repressed tumor formation in nude mice. Taken together, our findings demonstrate that miR-146a suppresses HCC by down-regulating TRAF6. We also discovered that miR-146a may represent a novel potential candidate of the HCC carcinoma diagnostic marker in the long term.

miR-30 functions as an oncomiR in gastric cancer cells through regulation of P53-mediated mitochondrial apoptotic pathway

The present study was designed to investigate the role of miR-30 in the development of Gastric cancer (GC). miR-30 expression was increased in GC tissues and cell lines. Downregulation of miR-30 inhibited cell proliferation and promoted apoptosis in HGC-27 cells. Upregulation of miR-30 enhanced the proliferation and inhibited apoptosis. P53 expression was decreased in GC tissues. P53 expression was correlated with miR-30 expression. Downregulation of miR-30 increased P53 expression. Knockdown of P53 inhibited miR-30-inhibitor-induced suppression of cell proliferation and increase of apoptosis. Downregulation of miR-30 increased ROS generation which was inhibited by shP53. miR-30 inhibitors induced a decrease in mitochondrial oxygen consumption, cytoplasmic release of cytochrome c, and activation of Caspase 3 and 9, activating mitochondrial apoptotic pathway. Downregulation of P53 and N-acetyl-cysteine suppressed miR-30 inhibitors-activated mitochondrial dysfunction and apoptotic events. In conclusion, we identified that miR-30 functioned as a potential oncomiR through P53/ROS-mediated regulation of mitochondrial apoptotic pathway.

MiR-300 suppresses laryngeal squamous cell carcinoma proliferation and metastasis by targeting ROS1

Laryngeal squamous cell carcinoma (LSCC) is a common aggressive head and neck cancer with high mortality and incidence. MicroRNAs (miRNAs) are short, non-coding and endogenous RNAs that posttranscriptionally inhibit gene expression. In this study, we showed that miR-300 expression was downregulated in LSCC tissues compared with adjacent no-tumor tissues. MiR-300 overexpression inhibited Hep-2 cell proliferation, as well as the expression of ki-67 and PCNA. Moreover, overexpression of miR-300 repressed the cell invasion in Hep-2 cells. We identified c-ros oncogene 1 receptor tyrosine kinase (ROS1) as a direct target gene of miR-300 in Hep-2 cell. Furthermore, ROS1 expression was upregulated in LSCC tissues compared with adjacent no-tumor tissues. Interesting, there were an inverse correlation between ROS1 and miR-300 expression in the LSCC tissues. Overexpression of ROS1 increased the Hep-2 cells proliferation and invasion. Overexpression of ROS1 abrogated miR-300 induced cell growth and invasion inhibition. Therefore, our data suggested that miR-300 acted as a tumor suppressive gene in LSCC.

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

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

Targeting oncomiRNAs and mimicking tumor suppressor miRNAs: Νew trends in the development of miRNA therapeutic strategies in oncology (Review)

MicroRNA (miRNA or miR) therapeutics in cancer are based on targeting or mimicking miRNAs involved in cancer onset, progression, angiogenesis, epithelial-mesenchymal transition and metastasis. Several studies conclusively have demonstrated that miRNAs are deeply involved in tumor onset and progression, either behaving as tumor-promoting miRNAs (oncomiRNAs and metastamiRNAs) or as tumor suppressor miRNAs. This review focuses on the most promising examples potentially leading to the development of anticancer, miRNA-based therapeutic protocols. The inhibition of miRNA activity can be readily achieved by the use of miRNA inhibitors and oligomers, including RNA, DNA and DNA analogues (miRNA antisense therapy), small molecule inhibitors, miRNA sponges or through miRNA masking. On the contrary, the enhancement of miRNA function (miRNA replacement therapy) can be achieved by the use of modified miRNA mimetics, such as plasmid or lentiviral vectors carrying miRNA sequences. Combination strategies have been recently developed based on the observation that i) the combined administration of different antagomiR molecules induces greater antitumor effects and ii) some anti-miR molecules can sensitize drug-resistant tumor cell lines to therapeutic drugs. In this review, we discuss two additional issues: i) the combination of miRNA replacement therapy with drug administration and ii) the combination of antagomiR and miRNA replacement therapy. One of the solid results emerging from different independent studies is that miRNA replacement therapy can enhance the antitumor effects of the antitumor drugs. The second important conclusion of the reviewed studies is that the combination of anti-miRNA and miRNA replacement strategies may lead to excellent results, in terms of antitumor effects.

MicroRNAs May Serve as Emerging Molecular Biomarkers for Diagnosis and Prognostic Assessment or as Targets for Therapy in Gastric Cancer

Gastric cancer (GC) is one of the most common cancers, with high incidences in East Asia countries. Most GC patients have been reported with low early diagnosis rate and show extremely poor prognosis. Therefore, it is necessary to develop novel and more sensitive biomarkers to improve early diagnosis and therapy in order to provide longer survival and better quality of life for gastric cancer patients. MicroRNAs (miRNAs) play crucial roles in GC development and progression. miRNAs have emerged as a novel molecular biomarker for cancer diagnosis, prognosis and therapy with surprising stability in tissues, serum or other body fluids. This review summarizes major advances in our current knowledge about potential miRNA biomarkers for GC that have been reported in the past two years.

Tissue microRNAs as predictive markers for gastric cancer patients undergoing palliative chemotherapy

MicroRNAs have the potential to become valuable predictive markers for gastric cancer. Samples of biopsy tissue, routinely taken from gastric cancer patients undergoing palliative chemotherapy, constitute suitable material for microRNA profiling with the aim of predicting the effect of chemotherapy. Our study group consisted of 54 patients, all of whom underwent palliative chemotherapy based on 5-fluorouracil (5-FU) or 5-FU in combination with platinum derivatives between 2000 and 2013. The expression of 29 selected microRNAs and genes BRCA1, ERCC1, RRM1 and TS, in gastric cancer tissue macrodissected from FFPE tissue samples, was measured by quantitative RT-PCR. The relationship between gene expression levels and time to progression (TTP) and overall survival (OS) was analysed. From the set of the 29 microRNAs of interest, we found high expression of miR-150, miR-342-3p, miR-181b, miR-221, miR-224 and low levels of miR-520h relate to shorter TTP. High levels of miR-150, miR-192, miR-224, miR-375 and miR-342-3p related to shorter OS. In routinely available FFPE tissue samples, we found 6 miRNAs with a relation to TTP, which may serve as predictors of the effectiveness of palliative treatment in gastric cancer patients. These miRNAs could also help in deciding whether to indicate palliative chemotherapy.

Emerging molecular basis of hematogenous metastasis in gastric cancer

Lymphatic metastasis is commonly observed in gastric cancer (GC), but hematogenous metastasis is more likely responsible for the cancer-related mortality. Since Stephen Paget first introduced the “seed and soil hypothesis” a century ago, growing evidence recognizes that numerous essential secreted factors and signaling pathway effectors participate in the pre-metastatic niche formation and distant organ metastasis. The cross-talk between GC cells and surrounding microenvironment may consist of a series of interrelated steps, including epithelial mesenchymal transition, intravasation into blood vessels, circulating tumor cell translocation, and secondary organ metastasis. Secreted factors including vascular endothelial growth factor (VEGF), matrix metalloproteinases and cancer-derived extracellular vesicles, especially exosomes, are essential in formation of premetastatic niche. Circulating tumor cells and microRNAs represent as ‘‘metastatic intermediates’’ between primary tumors and sites of dissemination. Many biomarkers have been identified as novel metastatic markers and prognostic effectors. In addition, molecular therapy has been designed to target biomarkers such as growth factors (human epidermal growth factor receptor 2, VEGF) and chemokines, although they have not clearly proven to be effective in inhibiting GC metastasis in clinical trials. In this review, we will systematically discuss the emerging molecules and their microenvironment in hematogenous metastasis of GC, which may help us to find new therapeutic strategies in the future.

miR-211 suppresses hepatocellular carcinoma by downregulating SATB2

Dysregulation of microRNAs (miRs) is involved in carcinogenesis. Deregulation of miR-211 has recently been observed in many tumors, but its function in hepatocellular carcinoma (HCC) is still unknown. Here we found that miR-211 was decreased in HCC cancer tissues compared with adjacent normal tissues. We also found that overexpression of miR-211 repressed proliferation and invasion in HepG2 and SMMC7721 cells. Luciferase reporter assays and western blot indicated that special AT-rich sequence-binding protein-2 (SATB2), is a direct target of miR-211. The expression of SATB2 was upregulated in HCC cancer tissues and cell lines and miR-211 levels inversely correlated with SATB2 levels in HCC. Importantly, SATB2 rescued the miR-211-mediated inhibition of cell invasion and proliferation. Finally, reintroduction of miR-211 repressed tumor formation of HCC in xenograft mice. This study provides insights into molecular mechanisms that miR-211 contributed to HCC.

Emerging roles of non-coding RNAs in gastric cancer: Pathogenesis and clinical implications

Gastric cancer is a leading cause of cancer-related deaths. However, the mechanisms underlying gastric carcinogenesis remain largely unclear. The association of non-coding RNAs (ncRNAs) with cancer has been widely studied during the past decade. In general, ncRNAs have been classified as small ncRNAs, including microRNAs (miRNAs), and long non-coding RNAs (lncRNAs). Emerging evidence shows that miRNAs and lncRNAs play key roles in the formation and progression of many cancers. In this review, we focus on the regulation of miRNAs and lncRNAs in gastric cancer. miRNAs and lncRNAs appear to be involved in gastric tumor growth, invasion, and metastasis and in establishment of the gastric tumor microenvironment through various mechanisms. Furthermore, we also discuss the possibilities of establishing miRNAs and lncRNAs as potential biomarkers and therapeutic targets for gastric cancer. Taken together, we summarize the emerging roles of ncRNAs in gastric cancer development and their possible clinical significance.

Dysregulation of non-coding RNAs in gastric cancer

Gastric cancer (GC) is one of the most common cancers in the world and a significant threat to the health of patients, especially those from China and Japan. The prognosis for patients with late stage GC receiving the standard of care treatment, including surgery, chemotherapy and radiotherapy, remains poor. Developing novel treatment strategies, identifying new molecules for targeted therapy, and devising screening techniques to detect this cancer in its early stages are needed for GC patients. The discovery of non-coding RNAs (ncRNAs), primarily microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), helped to elucidate the mechanisms of tumorigenesis, diagnosis and treatment of GC. Recently, significant research has been conducted on non-coding RNAs and how the regulatory dysfunction of these RNAs impacts the tumorigenesis of GC. In this study, we review papers published in the last five years concerning the dysregulation of non-coding RNAs, especially miRNAs and lncRNAs, in GC. We summarize instances of aberrant expression of the ncRNAs in GC and their effect on survival-related events, including cell cycle regulation, AKT signaling, apoptosis and drug resistance. Additionally, we evaluate how ncRNA dysregulation affects the metastatic process, including the epithelial-mesenchymal transition, stem cells, transcription factor activity, and oncogene and tumor suppressor expression. Lastly, we determine how ncRNAs affect angiogenesis in the microenvironment of GC. We further discuss the use of ncRNAs as potential biomarkers for use in clinical screening, early diagnosis and prognosis of GC. At present, no ideal ncRNAs have been identified as targets for the treatment of GC.

Circulating microRNAs and long non-coding RNAs in gastric cancer diagnosis: An update and review

Gastric cancer (GC) is the fourth most common cancer and the third leading cause of cancer mortality worldwide. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most popular non-coding RNAs in cancer research. To date, the roles of miRNAs and lncRNAs have been extensively studied in GC, suggesting that miRNAs and lncRNAs represent a vital component of tumor biology. Furthermore, circulating miRNAs and lncRNAs are found to be dysregulated in patients with GC compared with healthy individuals. Circulating miRNAs and lncRNAs may function as promising biomarkers to improve the early detection of GC. Multiple possibilities for miRNA secretion have been elucidated, including active secretion by microvesicles, exosomes, apoptotic bodies, high-density lipoproteins and protein complexes as well as passive leakage from cells. However, the mechanism underlying lncRNA secretion and the functions of circulating miRNAs and lncRNAs have not been fully illuminated. Concurrently, to standardize results of global investigations of circulating miRNAs and lncRNAs biomarker studies, several recommendations for pre-analytic considerations are put forward. In this review, we summarize the known circulating miRNAs and lncRNAs for GC diagnosis. The possible mechanism of miRNA and lncRNA secretion as well as methodologies for identification of circulating miRNAs and lncRNAs are also discussed. The topics covered here highlight new insights into GC diagnosis and screening.

miR-375 Modulates Radiosensitivity of HR-HPV-Positive Cervical Cancer Cells by Targeting UBE3A through the p53 Pathway

Background

Prediction of radioresistance of HR-HPV-positive (+) cervical cancer, especially before the course of radiotherapy, is quite beneficial to develop an optimal treatment strategy for individual patients. Unfortunately, the mechanisms responsible for radioresistance of cervical cancer are still largely unexplored. HR-HPV infection leads to a series of changes to normal biophysical process, including miRNAs expression. In this study, we explored the association between miR-375 and radioresistance in HR-HPV (+) cervical cancer.

Material/Methods

qRT-PCR analysis was performed to determine miR-375 expression in HR-HPV-positive (+) cervical cancer patients and in HPV-16-positive SiHa and HPV-18-positive HeLa cervical cancer cell lines. The influence of miR-375 on radiosensitivity and the downstream regulative network were further explored in the cell line models.

Results

The results verified a putative binding site between miR-375 and UBE3A. miR-375 overexpression could significantly reduce UBE3A expression. UBE3A knockdown led to significantly reduced cell survival under radiation treatment. miR-375 promoted radiosensitivity of HR-HPV (+) cancer through decreasing p53 degradation and thereby increasing radiation-induced apoptosis.

Conclusions

The miR-375-UBE3A axis is important in modulating radiosensitivity of HR-HPV (+) cervical cancer.

MicroRNA-375 Suppresses Extracellular Matrix Degradation and Invadopodial Activity in Head and Neck Squamous Cell Carcinoma

CONTEXT

Head and neck squamous cell carcinoma (HNSCC) is a highly invasive cancer with an association with locoregional recurrence and lymph node metastasis. We have previously reported that low microRNA-375 (miR-375) expression levels correlate with poor patient survival, increased locoregional recurrence, and distant metastasis. Increasing miR-375 expression in HNSCC cell lines to levels found in normal cells results in suppressed invasive properties. HNSCC invasion is mediated in part by invadopodia-associated degradation of the extracellular matrix.

OBJECTIVE

To determine whether elevated miR-375 expression in HNSCC cell lines also affects invadopodia formation and activity.

DESIGN

For evaluation of the matrix degradation properties of the HNSCC lines, an invadopodial matrix degradation assay was used. The total protein levels of invadopodia-associated proteins were measured by Western blot analyses. Immunoprecipitation experiments were conducted to evaluate the tyrosine phosphorylation state of cortactin. Human protease arrays were used for the detection of the secreted proteases. Quantitative real time-polymerase chain reaction measurements were used to evaluate the messenger RNA (mRNA) expression of the commonly regulated proteases.

RESULTS

Increased miR-375 expression in HNSCC cells suppresses extracellular matrix degradation and reduces the number of mature invadopodia. Higher miR-375 expression does not reduce cellular levels of selected invadopodia-associated proteins, nor is tyrosine phosphorylation of cortactin altered. However, HNSCC cells with higher miR-375 expression had significant reductions in the mRNA expression levels and secreted levels of specific proteases.

CONCLUSIONS

MicroRNA-375 regulates invadopodia maturation and function potentially by suppressing the expression and secretion of proteases.

Analysis of Deregulated microRNAs and Their Target Genes in Gastric Cancer

BACKGROUND

MicroRNAs (miRNAs) are widely studied non-coding RNAs that modulate gene expression. MiRNAs are deregulated in different tumors including gastric cancer (GC) and have potential diagnostic and prognostic implications. The aim of our study was to determine miRNA profile in GC tissues, followed by evaluation of deregulated miRNAs in plasma of GC patients. Using available databases and bioinformatics methods we also aimed to evaluate potential target genes of confirmed differentially expressed miRNA and validate these findings in GC tissues.

METHODS

The study included 51 GC patients and 51 controls. Initially, we screened miRNA expression profile in 13 tissue samples of GC and 12 normal gastric tissues with TaqMan low density array (TLDA). In the second stage, differentially expressed miRNAs were validated in a replication cohort using qRT-PCR in tissue and plasma samples. Subsequently, we analyzed potential target genes of deregulated miRNAs using bioinformatics approach, determined their expression in GC tissues and performed correlation analysis with targeting miRNAs.

RESULTS

Profiling with TLDA revealed 15 deregulated miRNAs in GC tissues compared to normal gastric mucosa. Replication analysis confirmed that miR-148a-3p, miR-204-5p, miR-223-3p and miR-375 were consistently deregulated in GC tissues. Analysis of GC patients' plasma samples showed significant down-regulation of miR-148a-3p, miR-375 and up-regulation of miR-223-3p compared to healthy subjects. Further, using bioinformatic tools we identified targets of replicated miRNAs and performed disease-associated gene enrichment analysis. Ultimately, we evaluated potential target gene BCL2 and DNMT3B expression by qRT-PCR in GC tissue, which correlated with targeting miRNA expression.

CONCLUSIONS

Our study revealed miRNA profile in GC tissues and showed that miR-148a-3p, miR-223-3p and miR-375 are deregulated in GC plasma samples, but these circulating miRNAs showed relatively weak diagnostic performance as sole biomarkers. Target gene analysis demonstrated that BCL2 and DNMT3B expression in GC tissue correlated with their targeting miRNA expression.

MicroRNA-410 promotes cell proliferation by targeting BRD7 in non-small cell lung cancer

miR-410 acts as an oncogene or tumor suppressor gene in some malignancies. However, its role in NSCLC is still unknown. In this study, we showed that the expression of miR-410 was up-regulated in both human NSCLC tissues and cells. Overexpression of miR-410 promoted cell proliferation, migration, and invasion of NSCLC. In addition, bromodomain-containing protein 7 (BRD7) was a direct target of miR-410. MiR-410-mediated downregulation of BRD7 led to increase Akt phosphorylation. Inhibition of Akt phosphorylation can rescue the effect of miR-410 on NSCLC cell. The expression of BRD7 was downregulated in NSCLC and was inversely expressed with miR-410 in NSCLC. Our data provided new knowledge regarding the role of miR-410 in the lung cancer progression.