miR-218 Inhibits Proliferation, Migration, and EMT of Gastric Cancer Cells by Targeting WASF3

High Expression of miR-218-5p in the Peripheral Blood Stream and Tumor Tissues of Pediatric Patients with Sarcomas

Sarcomas are malignant tumors that may metastasize and the course of the disease is highly aggressive in children and young adults. Because of the rare incidence of sarcomas and the heterogeneity of tumors, there is a need for non-invasive diagnostic and prognostic biomarkers in sarcomas. The aim of the study was to investigate the level of miR-218-5p in peripheral blood and tumor tissue samples of Ewing's sarcoma, osteosarcoma, spindle cell sarcoma patients, and healthy controls, and assessed whether the corresponding molecule was a diagnostic and prognostic biomarker. The study was performed patients (n = 22) diagnosed and treated with Ewing's sarcoma and osteosarcoma and in a control group of 22 healthy children who were matched for age, gender, and ethnicity with the patient group. The expression level of miR-218-5p in RNA samples from peripheral blood and tissue samples were analyzed using the RT-PCR and the expression level of miR-218-5p was evaluated by comparison with the levels in patients and healthy controls. The expression level of miR-218-5p was found to be statistically higher (3.33-fold, p = 0.006) in pediatric patients with sarcomas and when the target genes of miR-218-5p were investigated using the bioinformatics tools, the miR-218-5p was found as an important miRNA in cancer. In this study, the miR-218-5p was shown for the first time to have been highly expressed in the peripheral blood and tumor tissue of sarcoma patients. The results suggest that miR-218-5p can be used as a diagnostic and prognostic biomarker in sarcomas and will be evaluated as an important therapeutic target.

Role of STAT3 in cancer cell epithelial‑mesenchymal transition (Review)

Since its discovery, the role of the transcription factor, signal transducer and activator of transcription 3 (STAT3), in both normal physiology and the pathology of numerous diseases, including cancer, has been extensively studied. STAT3 is aberrantly activated in different types of cancer, fulfilling a critical role in cancer progression. The biological process, epithelial‑mesenchymal transition (EMT), is indispensable for embryonic morphogenesis. During the development of cancer, EMT is hijacked to confer motility, tumor cell stemness, drug resistance and adaptation to changes in the microenvironment. The aim of the present review was to outline recent advances in knowledge of the role of STAT3 in EMT, which may contribute to the understanding of the function of STAT3 in EMT in various types of cancer. Delineating the underlying mechanisms associated with the STAT3‑EMT signaling axis may generate novel diagnostic and therapeutic options for cancer treatment.

Biological and therapeutic viewpoints towards role of miR-218 in human cancers: Revisiting molecular interactions and future clinical translations

Understanding the exact pathogenesis of cancer is difficult due to heterogenous nature of tumor cells and multiple factors that cause its initiation and development. Treatment of cancer is mainly based on surgical resection, chemotherapy, radiotherapy and their combination, while gene therapy has been emerged as a new kind of therapy for cancer. Post-transcriptional regulation of genes has been of interest in recent years and among various types of epigenetic factors that can modulate gene expression, short non-coding RNAs known as microRNAs (miRNAs) have obtained much attention. The stability of mRNA decreases by miRNAs to repress gene expression. miRNAs can regulate tumor malignancy and biological behavior of cancer cells and understanding their function in tumorigenesis can pave the way towards developing new therapeutics in future. One of the new emerging miRNAs in cancer therapy is miR-218 that increasing evidence highlights its anti-cancer activity, while a few studies demonstrate its oncogenic function. The miR-218 transfection is promising in reducing progression of tumor cells. miR-218 shows interactions with molecular mechanisms including apoptosis, autophagy, glycolysis and EMT, and the interaction is different. miR-218 induces apoptosis, while it suppresses glycolysis, cytoprotective autophagy and EMT. Low expression of miR-218 can result in development of chemoresistance and radio-resistance in tumor cells and direct targeting of miR-218 as a key player is promising in cancer therapy. LncRNAs and circRNAs are nonprotein coding transcripts that can regulate miR-218 expression in human cancers. Moreover, low expression level of miR-218 can be observed in human cancers such as brain, gastrointestinal and urological cancers that mediate poor prognosis and low survival rate.

Targeting the WASF3 complex to suppress metastasis

Wiskott-Aldrich syndrome protein family members (WASF) regulate the dynamics of the actin cytoskeleton, which plays an instrumental role in cancer metastasis and invasion. WASF1/2/3 forms a hetero-pentameric complex with CYFIP1/2, NCKAP1/1 L, Abi1/2/3 and BRK1 called the WASF Regulatory Complex (WRC), which cooperatively regulates actin nucleation by WASF1/2/3. Activation of the WRC enables actin networking and provides the mechanical force required for the formation of lamellipodia and invadopodia. Although the WRC drives cell motility essential for several routine physiological functions, its aberrant deployment is observed in cancer metastasis and invasion. WASF3 expression is correlated with metastatic potential in several cancers and inversely correlates with overall progression-free survival. Therefore, disruption of the WRC may serve as a novel strategy for targeting metastasis. Given the complexity involved in the formation of the WRC which is largely comprised of large protein-protein interfaces, there are currently no inhibitors for WASF3. However, several constrained peptide mimics of the various protein-protein interaction interfaces within the WRC were found to successfully disrupt WASF3-mediated migration and invasion. This review explores the role of the WASF3 WRC in driving metastasis and how it may be selectively targeted for suppression of metastasis.

LncRNA LNCOC1 is Upregulated in Melanoma and Serves as a Potential Regulatory Target of miR-124 to Suppress Cancer Cell Invasion and Migration

Background

A cascade of genes and pathways have been reported in the precise regulation of malignant melanoma (MM). Previous study has demonstrated that lncRNA LNCOC1 is an oncogenic factor in the pathogenesis and development of various cancers. The present study explored the functionalities of LNCOC1 and its interactions with miR-124 in MM.

Methods

A total of 65 melanoma patients were enrolled in this study. The expression of LNCOC1 and miR-124 after cell transfection were detected by RT-qPCR. The migration rates of SK-MEL-3 and A375 cells after transient transfection with LNCOC1 expression vector and miR-124 mimic was detected by trans-well assay.

Results

LNCOC1 was accumulated to high levels in melanoma, and it was significantly correlated with the low survival rate of melanoma patients. Our bioinformatics data showed that miR-124 could target LNCOC1. Overexpression of miR-124 could downregulate LNCOC1. However, up-regulated the expression of LNCOC1 did not affect the expression of miR-124. Our correlation analysis also revealed that the expression of LNCOC1 and miR-124 were inversely correlated in both melanoma tissues and non-tumor tissues. The trans-well invasion and migration assays indicated that overexpression of miR-124 inhibited the melanoma cell invasion and migration. However, overexpression of LNCOC1 promoted melanoma cell invasion and migration.

Conclusion

LNCOC1 is upregulated in melanoma, which can be considered as a potential target of miR-124 in modulating melanoma cell invasion and migration. LNCOC1 may also be an interfering target of MM therapy.

In Silico Optimized Stapled Peptides Targeting WASF3 in Breast Cancer

Wiskott-Aldrich Syndrome Protein Family (WASF) members regulate actin cytoskeletal dynamics, and WASF3 is directly associated with breast cancer metastasis and invasion. WASF3 forms a heteropentameric complex with CYFIP, NCKAP, ABI, and BRK1, called the WASF Regulatory Complex (WRC), which cooperatively regulates actin nucleation by WASF3. Since aberrant deployment of the WRC is observed in cancer metastasis and invasion, its disruption provides a novel avenue for targeting motility in breast cancer cells. Here, we report the development of a second generation WASF3 mimetic peptide, WAHMIS-2, which was designed using a combination of structure-guided design, homology modeling, and in silico optimization to disrupt binding of WASF3 to the WRC. WAHMIS-2 was found to permeate cells and inhibit cell motility, invasion, and MMP9 expression with greater potency than its predecessor, WAHM1. Targeted disruption of WASF3 from the WRC may serve as a useful strategy for suppression of breast cancer metastasis.

Identification of Key Circulating Exosomal microRNAs in Gastric Cancer

Exosomal miRNAs (EmiRs) can be used for prediction of gastric cancer (GC) development. Supposedly, both plasma and urinary microRNAs can also be potential biomarkers for screening, but the diagnostic values of EmiRs in blood and urine are not fully studied. We here collected both types of samples from GC patients and healthy individuals and conducted miRNA sequencing to identify key members of EmiRs in GC. The exosomes samples derived from blood and urine were collected from 3 healthy individuals and 7 GC patients. Differentially expressed miRNAs (DEmiRNAs) were acquired, ontology enrichment analysis and Protein-protein Interaction (PPI) enrichment analysis were performed. There were 8 DEmiRNAs in the serum and 3 DEmiRNAs in the urine. For GC patients, there were three up-regulated DEmiRNAs (hsa-miR-130b-3p, hsa-miR-151a-3p and hsa-miR-15b-3p) in the serum exosomes, and one up-regulated DEmiRNA (hsa-miR-1246) in the urinary exosomes. Using miRNA target prediction databases, we found 418 common targets of hsa-miR-15b-3p, 35 common targets of hsa-miR-151a-3p, 117 common targets of hsa-miR-130b-3p, and 357 common targets of hsa-miR-1246. Some commonly enriched ontology terms were found, including GO BP terms like cell surface receptor signaling pathway involved in cell-cell signaling, positive regulation of catabolic process, morphogenesis of an epithelium, and GO CC terms perinuclear region of cytoplasm. The PPI network show some key nodes, including TAOK1, CMTM6, SCN3A, WASF3, IGF1, CNOT7, GABRG1, PRKD1. Together, this study provided an integrative analysis of expression profile of key circulating exosomal microRNAs. Four key exosomal miRNAs (hsa-miR-130b-3p, hsa-miR-151a-3p and hsa-miR-15b-3p) and the interaction network or enrichments based on their targets (TAOK1, CMTM6, SCN3A, WASF3, IGF1, CNOT7, GABRG1, PRKD1) may provide a reference of the molecular mechanisms in the GC development.

The Role of Extracellular Vesicles in Mediating Resistance to Anticancer Therapies

Although advances in targeted therapies have driven great progress in cancer treatment and outcomes, drug resistance remains a major obstacle to improving patient survival. Several mechanisms are involved in developing resistance to both conventional chemotherapy and molecularly targeted therapies, including drug efflux, secondary mutations, compensatory genetic alterations occurring upstream or downstream of a drug target, oncogenic bypass, drug activation and inactivation, and DNA damage repair. Extracellular vesicles (EVs) are membrane-bound lipid bilayer vesicles that are involved in cell-cell communication and regulating biological processes. EVs derived from cancer cells play critical roles in tumor progression, metastasis, and drug resistance by delivering protein and genetic material to cells of the tumor microenvironment. Understanding the biochemical and genetic mechanisms underlying drug resistance will aid in the development of new therapeutic strategies. Herein, we review the role of EVs as mediators of drug resistance in the context of cancer.

The Impact of Non-coding RNAs in the Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is a course of action that enables a polarized epithelial cell to undertake numerous biochemical alterations that allow it to adopt features of mesenchymal cells such as high migratory ability, invasive properties, resistance to apoptosis, and importantly higher-order formation of extracellular matrix elements. EMT has important roles in implantation and gastrulation of the embryo, inflammatory reactions and fibrosis, and transformation of cancer cells, their invasiveness and metastatic ability. Regarding the importance of EMT in the invasive progression of cancer, this process has been well studies in in this context. Non-coding RNAs (ncRNAs) have been shown to exert critical function in the regulation of cellular processes that are involved in the EMT. These processes include regulation of some transcription factors namely SNAI1 and SNAI2, ZEB1 and ZEB2, Twist, and E12/E47, modulation of chromatin configuration, alternative splicing, and protein stability and subcellular location of proteins. In the present paper, we describe the influence of ncRNAs including microRNAs and long non-coding RNAs in the EMT process and their application as biomarkers for this process and cancer progression and their potential as therapeutic targets.

Targeting WASF3 Signaling in Metastatic Cancer

Increasing evidence indicates that cancer metastasis is regulated by specific genetic pathways independent of those controlling tumorigenesis and cancer growth. WASF3, a Wiskott–Aldrich syndrome protein family member, appears to play a major role not only in the regulation of actin cytoskeleton dynamics but also in cancer cell invasion/metastasis. Recent studies have highlighted that WASF3 is a master regulator and acts as a pivotal scaffolding protein, bringing the various components of metastatic signaling complexes together both spatially and temporally. Herein, targeting WASF3 at the levels of transcription, protein stability, and phosphorylation holds great promise for metastasis suppression, regardless of the diverse genetic backgrounds associated with tumor development. This review focuses on the critical and distinct contributions of WASF3 in the regulation of signal pathways promoting cancer cell invasion and metastasis.

Silencing of Long Noncoding RNA LINC00324 Interacts with MicroRNA-3200-5p to Attenuate the Tumorigenesis of Gastric Cancer via Regulating BCAT1

PURPOSE

This study was aimed at exploring the effect of long noncoding RNA LINC00324 (LINC00324) on gastric cancer (GC) and the potential molecular mechanisms.

METHODS

The expression of LINC00324 and miR-3200-5p in GC tissues and cells was detected by qRT-PCR. LINC00324 was silenced in GC cells by transfection of si-LINC00324. Then, the proliferation, migration, and invasion of GC cells were analyzed by MTT, wound healing, and transwell assays, respectively. The interactions between LINC00324 and miR-3200-5p and between miR-3200-5p and BCAT1 were determined by a dual-luciferase reporter and/or RNA pull-down assay.

RESULTS

The expression of LINC00324 was upregulated in GC cells and tissues, but miR-3200-5p was downregulated. Silencing of LINC00324 inhibited the proliferation, migration, and invasion of GC cells. LINC00324 directly targeted miR-3200-5p, and miR-3200-5p directly targeted BCAT1. si-LINC00324 negatively regulated BCAT1 expression via binding to miR-3200-5p. Furthermore, silencing of LINC00324 reversed the promoting effects of BCAT1 on the proliferation, migration, and invasion of GC cells.

CONCLUSION

Silencing of LINC00324 inhibited the proliferation, migration, and invasion of GC cells through regulating the miR-3200-5p/BCAT1 axis.

microRNA-501-5p promotes cell proliferation and migration in gastric cancer by downregulating LPAR1

In spite of the achievement in treatment, the gastric cancer (GC) mortality still remains high. MicroRNAs (miRNAs) are a group of small noncoding RNAs that play a crucial part in tumor progression. In this study, we explored the expression and function of microRNA-501-5p (miR-501-5p) in GC cell lines. Quantitative real-time polymerase chain reaction assay results suggested that miR-501-5p was significantly upregulated in GC tissues and cell lines. And, the Cell Counting Kit-8 colony formation and cell migration assay results showed that the downregulation of miR-501-5p decreased GC cell proliferation and migration. Besides that, we found that GC cell cycle was arrested in G2 phase and cell apoptosis rate was increased by silencing the expression of miR-501-5p in GC cell lines using the flow cytometry. We also found that miR-501-5p could directly target lysophosphatidic acid receptor 1 (LPAR1) and negatively regulate LPAR1 expression in GC cell lines by performing dual-luciferase reporter gene assay and Western blot analysis. And, LPAR1 was significantly downregulated in GC tissues and inversely correlated with miR-501-5p expression. Furthermore, LPAR1 downregulation promoted cell proliferation and migration, which were attenuated by cotransfection of miR-501-5p inhibitor in GC cells. In conclusion, miR-501-5p can promote GC cell proliferation and migration by targeting and downregulating LPAR1. miR-501-5p/LPAR1 may become a potential therapeutic target for GC treatment.

MicroRNA-561 Affects Proliferation and Cell Cycle Transition Through PTEN/AKT Signaling Pathway by Targeting P-REX2a in NSCLC

MicroRNAs (miRNAs) play crucial roles in tumorigenesis and tumor progression. miR-561 has been reported to be downregulated in gastric cancer and affects cancer cell proliferation and metastasis. However, the role and underlying molecular mechanism of miR-561 in human non-small cell lung cancer (NSCLC) remain unknown and need to be further elucidated. In this study, we discovered that miR-561 expression was downregulated in human NSCLC tissues and cell lines. The overexpression of miR-561 inhibited NSCLC cell proliferation and cell cycle G₁/S transition and induced apoptosis. The inhibition of miR-561 facilitated cell proliferation and G₁/S transition and suppressed apoptosis. miR-561 expression was inversely correlated with P-REX2a expression in NSCLC tissues. P-REX2a was confirmed to be a direct target of miR-561 using a luciferase reporter assay. The overexpression of miR-561 decreased P-REX2a expression, and the suppression of miR-561 increased P-REX2a expression. Particularly, P-REX2a silencing recapitulated the cellular and molecular effects observed upon miR-561 overexpression, and P-REX2a overexpression counteracted the effects of miR-561 overexpression on NSCLC cells. Moreover, both exogenous expression of miR-561 and silencing of P-REX2a resulted in suppression of the PTEN/AKT signaling pathway. Our study demonstrates that miR-561 inhibits NSCLC cell proliferation and G₁/S transition and induces apoptosis through suppression of the PTEN/AKT signaling pathway by targeting P-REX2a. These findings indicate that miR-561 plays a significant role in NSCLC progression and serves as a potential therapeutic target for NSCLC.

miRNome Reveals New Insights Into the Molecular Biology of Field Cancerization in Gastric Cancer

BACKGROUND

MicroRNAs (miRNAs) play an important role in gastric carcinogenesis and have been associated with gastric field cancerization; however, their role is not fully understood in this process. We performed the miRNome sequencing of non-cancerous, adjacent to tumor and gastric cancer samples to understand the involvement of these small RNAs in gastric field cancerization.

METHODS

We analyzed samples of patients without cancer as control (non-cancerous gastric samples) and adjacent to cancer and gastric cancer paired samples, and considered miRNAs with |log2(fold change)| > 2 and Padj < 0.05 to be statistically significant. The identification of target genes, functional analysis and enrichment in KEGG pathways were realized in the TargetCompare, miRTargetLink, and DAVID tools. We also performed receiver operating characteristic (ROC) curves and miRNAs that had an AUC > 0.85 were considered to be potential biomarkers.

RESULTS

We found 14 miRNAs exclusively deregulated in gastric cancer, of which six have potential diagnostic value for advanced disease. Nine miRNAs with known tumor suppressor activities (TS-miRs) were deregulated exclusively in adjacent tissue. Of these, five have potential diagnostic value for the early stages of gastric cancer. Functional analysis of these TS-miRs revealed that they regulate important cellular signaling pathways (PI3K-Akt, HIF-1, Ras, Rap1, ErbB, and MAPK signaling pathways), that are involved in gastric carcinogenesis. Seven miRNAs were differentially expressed in both gastric cancer and adjacent regarding to non-cancerous tissues; among them, hsa-miR-200a-3p and hsa-miR-873-5p have potential diagnostic value for early and advanced stages of the disease. Only hsa-miR-196a-5p was differentially expressed between adjacent to cancer and gastric cancer tissues. In addition, the other miRNAs identified in this study were not differentially expressed between adjacent to cancer and gastric cancer, suggesting that these tissues are very similar and that share these molecular changes.

CONCLUSION

Our results show that gastric cancer and adjacent tissues have a similar miRNA expression profile, indicating that studied miRNAs are intimately associated with field cancerization in gastric cancer. The overexpression of TS-miRs in adjacent tissues may be a barrier against tumorigenesis within these pre-cancerous conditions prior to the eventual formation or relapse of a tumor. Additionally, these miRNAs have a great accuracy in discriminating non-cancerous from adjacent to tumor and cancer tissues and can be potentially useful as biomarkers for gastric cancer.

Roles of E-cadherin and Noncoding RNAs in the Epithelial-mesenchymal Transition and Progression in Gastric Cancer

The epithelial–mesenchymal transition (EMT) is thought to be at the root of invasive and metastatic cancer cell spreading. E-cadherin is an important player in this process, which forms the structures that establish and maintain cell–cell interactions. A partial or complete loss of E-cadherin expression in the EMT is presumably mediated by mechanisms that block the expression of E-cadherin regulators and involve the E-cadherin-associated transcription factors. The protein is involved in several oncogenic signaling pathways, such as the Wnt/β-catenin, Rho GTPase, and EGF/EGFR, whereby it plays a role in many tumors, including gastric cancer. Such noncoding transcripts as microRNAs and long noncoding RNAs—critical components of epigenetic control of gene expression in carcinogenesis—contribute to regulation of the E-cadherin function by acting directly or through numerous factors controlling transcription of its gene, and thus affecting not only cancer cell proliferation and metastasis, but also the EMT. This review focuses on the role of E-cadherin and the non-coding RNAs-mediated mechanisms of its expressional control in the EMT during stomach carcinogenesis.

Piwi like RNA-mediated gene silencing 1 gene as a possible major player in gastric cancer

AIM

To establish a permanent piwi like RNA-mediated gene silencing 1 (PIWIL1) gene knockout in AGP01 gastric cancer cell line using CRISPR-Cas9 system and analyze phenotypic modifications as well as gene expression alterations.

METHODS

CRISPR-Cas9 system used was purchased from Dharmacon GE Life Sciences (Lafayette, CO, United States) and permanent knockout was performed according to manufacturer’s recommendations. Wound-healing assay was performed to investigate the effect of PIWIL1 knockout on migration capability of cells and Boyden chamber invasion assay was performed to investigate the effect on invasion capability. For the gene expression analysis, a one-color microarray-based gene expression analysis kit (Agilent Technologies, Santa Clara, CA, United States) was used according to the protocol provided by the manufacturer.

RESULTS

PIWIL1 gene knockout caused a significant decrease in AGP01 migration capacity as well as a significant decrease in cell invasiveness. Moreover, functional analysis based on grouping of all differentially expressed mRNAs identified a total of 35 genes (5 up-regulated and 30 down-regulated) encoding proteins involved in cellular invasion and migration. According to current literature, 9 of these 35 genes (DOCK2, ZNF503, PDE4D, ABL1, ABL2, LPAR1, SMAD2, WASF3 and DACH1) are possibly related to the mechanisms used by PIWIL1 to promote carcinogenic effects related to migration and invasion, since their functions are consistent with the changes observed (being up- or down-regulated after knockout).

CONCLUSION

Taken together, these data reinforce the idea that PIWIL1 plays a crucial role in the signaling pathway of gastric cancer, regulating several genes involved in migration and invasion processes; therefore, its use as a therapeutic target may generate promising results in the treatment of gastric cancer.

Exosomal miR-1228 From Cancer-Associated Fibroblasts Promotes Cell Migration and Invasion of Osteosarcoma by Directly Targeting SCAI

Cancer-associated fibroblasts (CAFs) play a predominant role in regulating tumor progression. Understanding how CAFs communicate with osteosarcoma is crucial for developing novel approaches for osteosarcoma therapy. Exosomes are able to transmit messages between cells. In this study, we demonstrated that CAFs transfer exosomes to osteosarcoma cells, which promotes osteosarcoma cell migration and invasion. Using a miRNA microarray analysis, we identified 13 miRNAs that are significantly increased in exosomes derived from cancer-associated fibroblasts (CAFs) and corresponding paracancer fibroblasts (PAFs). In vitro studies further validated that the levels of microRNA-1228 (miR-1228) were increased in CAFs, its secreted exosomes, and in recipient osteosarcoma cells, which can downregulate endogenous SCAI mRNA and protein level in osteosarcoma. Furthermore, our findings demonstrate that SCAI was downregulated in osteosarcoma tissues. Taken together, this study provides evidence that CAF exosomal miR-1228 is able to promote osteosarcoma invasion and migration by targeting SCAI, which may represent a critical therapeutic target for osteosarcoma treatment.

Long non-coding RNA NNT-AS1 sponges miR-424/E2F1 to promote the tumorigenesis and cell cycle progression of gastric cancer

Long non‐coding RNAs (lncRNAs) have been illustrated to function as important regulators in carcinogenesis and cancer progression. However, the roles of lncRNA NNT‐AS1 in gastric cancer remain unclear. In the present study, we investigate the biological role of NNT‐AS1 in gastric cancer tumorigenesis. Results revealed that NNT‐AS1 expression level was significantly up‐regulated in GC tissue and cell lines compared with adjacent normal tissue and normal cell lines. The ectopic overexpression of NNT‐AS1 indicated the poor prognosis of GC patients. In vitro experiments validated that NNT‐AS1 knockdown suppressed the proliferation and invasion ability and induced the GC cell cycle progression arrest at G0/G1 phase. In vivo xenograft assay, NNT‐AS1 silencing decreased the tumour growth of GC cells. Bioinformatics online program predicted that miR‐424 targeted the 3′‐UTR of NNT‐AS1. Luciferase reporter assay, RNA‐immunoprecipitation (RIP) and RNA pull‐down assay validated the molecular binding within NNT‐AS1 and miR‐424, therefore jointly forming the RNA‐induced silencing complex (RISC). Moreover, E2F1 was verified to act as the target gene of NNT‐AS1/miR‐424, indicating the NNT‐AS1/miR‐424/E2F1 axis. In conclusion, our study indicates that NNT‐AS1 sponges miR‐424/E2F1 to facilitate GC tumorigenesis and cycle progress, revealing the oncogenic role of NNT‐AS1 for GC.

MicroRNA-599 suppresses glioma progression by targeting RAB27B

MicroRNAs (miRNAs/miRs) serve tumor promoting or suppressive roles in different human cancer types, including glioma; however, the regulatory underlying mechanism by which miR-599 affects glioma progression remains largely unknown. The aim of the present study was to investigate the expression of miR-599 in glioma, as well as the underlying regulatory mechanism. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to examine mRNA and protein expression, respectively. MTT, wound healing and transwell assays were conducted to study cell proliferation, migration and invasion, respectively. A dual-luciferase reporter gene assay was used to confirm the targeting association between miR-599 and Ras-related protein Rab-27B (hereafter RAB27B). In the present study, miR-599 expression was observed to be significantly downregulated in human glioma tissues and cell lines, when compared with normal brain tissues and normal human astrocyte cells, respectively. Low miR-599 expression was significantly associated with glioma progression. Ectopic expression of miR-599 caused a significant reduction in the proliferation, migration and invasion of U-87MG Uppsala and U251 cells. Bioinformatics analysis and dual-luciferase reporter gene assay data identified that RAB27B was a direct target gene of miR-599. The mRNA and protein expression of RAB27B was significantly downregulated following miR-599 overexpression in U-87MG Uppsala and U251 cells. Rescue experiments demonstrated that RAB27B rescued the miR-599-induced inhibition of glioma cell growth, migration and invasion. In addition, RAB27B expression was significantly upregulated in glioma tissues and cell lines, and the expression levels of RAB27B were inversely correlated with miR-599 levels in glioma tissues; therefore, the present study demonstrated that miR-599 exerts a tumor-suppressive role in glioma progression by targeting RAB27B, indicating that miR-599 may be used as a potential candidate for glioma treatment.

MicroRNA-218 inhibits the migration, epithelial-mesenchymal transition and cancer stem cell properties of prostate cancer cells

MicroRNA (miRNA) is a class of non-coding single-stranded RNA, able to regulate tumor-associated genes via binding the 3'-UTR of the target gene mRNA. Previous publications have demonstrated that miRNA-218 (miR-218) acts as a tumor-suppressive miRNA in various types of human cancer, including prostate cancer (PCa). However, the role of miR-218 in regulating PCa cell stemness and epithelial-mesenchymal transition remains unknown and requires further research. In the present study, it is demonstrated that miR-218 was downregulated in 2 PCa cell lines and could suppress cell migration, EMT and the exhibition of cancer stem cell-like properties. The expression of GLI family zinc finger 1 (Gli1) was inhibited by miR-218 overexpression, suggesting miR-218-suppression of Gli1 as a potential mechanism for the tumor-suppressive effect of miR-218. Overall, the results indicate that miR-218 served a critical role in the inhibition of PCa development. This may provide new insight for elucidating the mechanisms of PCa oncogenesis and suggests that miR-218 may be a novel therapeutic target for PCa.

MicroRNA-153 functions as a tumor suppressor in gastric cancer via targeting Kruppel-like factor 5

Various microRNAs (miRs) have been demonstrated to serve important roles in gastric cancer (GC). miR-153 in particular has been reported to serve a suppressive role in GC; however, the underlying mechanism remains unclear. In the present study Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to examine the mRNA and protein expression of Kruppel-like factor 5. An MTT, wound healing and transwell assay were used to study cell proliferation, migration and invasion, respectively. In the present study, quantitative polymerase chain reaction data indicated that miR-153 was significantly downregulated in GC tissues compared with the adjacent non-tumor tissues. In addition, the reduced expression of miR-153 was significantly associated with GC aggressiveness and poor prognosis of patients. The expression of miR-153 was also reduced in GC cell lines, including KATO III, NCI-N87, SNU-16 and SNU-5, when compared with normal gastric epithelial GES-1 cells. Overexpression of miR-153 in the GC SNU-5 cells by miR-153 mimic transfection significantly inhibited the cell proliferation, migration and invasion. Furthermore, KLF5 was identified as a target gene of miR-153 in SNU-5 cells by bioinformatics prediction. It was observed that KLF5 was significantly upregulated in GC tissues and cell lines, and its expression was negatively regulated by miR-153 in SNU-5 cells. Overexpression of KLF5 impaired the suppressive effects of miR-153 on the proliferation, migration and invasion of SNU-5 cells. In conclusion, the present study demonstrated that miR-153 serves a tumor suppressive role in GC, at least partly, through directly targeting KLF5, thus highlighting the clinical significance of miR-153 in GC.

MicroRNA‑195 inhibits cell proliferation, migration and invasion by targeting defective in cullin neddylation 1 domain containing 1 in cervical cancer

MicroRNAs (miRs), a class of small non-coding RNAs, have been demonstrated to perform promoting or suppressive roles in various types of human malignancy. Deregulation of miR-195 has been observed in numerous types of human cancer, including cervical cancer; however, the detailed molecular mechanism of miR-195 underlying the malignant progression of cervical cancer remains largely unclear. In the present study, miR-195 was significantly down-regulated in cervical cancer tissue samples compared with adjacent non-tumor tissue samples, and the reduced expression level of miR-195 was associated with node metastasis and an advanced clinical stage in cervical cancer. Furthermore, the patients with low miR-195 expression levels demonstrated shorter survival times when compared with those with high miR-195 expression levels. In vitro experiments indicated that miR-195 exerted suppressive effects on the proliferation, migration and invasion of cervical cancer cells. Luciferase reporter gene assay identified defective in cullin neddylation 1 domain containing 1 (DCUN1D1) as a novel target gene of miR-195 and the expression level of DCUN1D1 was identified to be negatively regulated by miR-195 in cervical cancer cells. DCUN1D1 was significantly upregulated in cervical cancer, with a negative correlation to miR-195 expression. Furthermore, upregulation of DCUN1D1 was associated with the malignant progression and poor prognosis of cervical cancer. DCUN1D1 overexpression attenuated the suppressive effects of miR-195 on the malignant phenotypes of cervical cancer cells. Notably, the expression levels of miR-195 were significantly lower in HeLa [human papilloma virus (HPV)18⁺] and SiHa (HPV16⁺) cells compared with those in C33A (HPV⁻) cells, and knockdown of E6 using small interfering RNA significantly increased the miR-195 expression while the DCUN1D1 expression level was reduced in HeLa and SiHa cells. Thus, these findings indicate that miR-195 exerts a suppressive role in cervical cancer by targeting DCUN1D1. Therefore, miR-195 may present as a potential therapeutic candidate for cervical cancer.

Nicotinamide N-methyltransferase promotes epithelial-mesenchymal transition in gastric cancer cells by activating transforming growth factor-β1 expression

Previous studies have demonstrated that nicotinamide N-methyltransferase (NNMT) is aberrantly expressed in a number of tumors. In the present study, it was demonstrated that the gene and protein levels of NNMT were significantly increased in gastric cancer cells. Furthermore, upregulation of NNMT significantly increased the expression of mesenchymal markers, including α-smooth muscle actin (SMA), vimentin and fibronectin, but decreased the levels of epithelial cadherin. Since transforming growth factor (TGF)-β1 may serve a key function in epithelial-mesenchymal transition (EMT), the effects of NNMT on the expression of TGF-β1 were investigated in BGC-823 cells. The results demonstrated that overexpression of NNMT significantly induced the expression of TGF-β1. However, knockdown of NNMT inhibited the expression of TGF-β1, mothers against decapentaplegic homolog (Smad)2 and α-SMA. Additionally, pre-incubation with TGF-β1 partially eliminated NNMT-mediated changes in EMT. Collectively, the results demonstrated that upregulation of NNMT in gastric cancer cells may increase the expression of TGF-β1, therefore activating TGF-β1/Smad signaling, which in turn promotes EMT.

microRNA-23a promotes cell growth and metastasis in gastric cancer via targeting SPRY2-mediated ERK signaling

microRNAs (miRs) serve important roles in various human cancer types. Recently, miR-23a has been indicated as an oncogene in gastric cancer, but the underlying mechanism remains unclear. In the present study, reverse transcription-quantitative polymerase chain reaction and western blot analysis was used to explore the effects of miR-23a in gastric cancer. Additionally, cell proliferation, migration and invasion were examined using an MTT assay, wound healing assay and Transwell assay, respectively. Furthermore, a luciferase reporter gene assay was used to confirm the target association. It was determined that miR-23a was significantly upregulated in gastric cancer tissues and cell lines compared with adjacent tissues, and a normal gastric epithelial cell line. Furthermore, its upregulation was significantly associated with cancer progression and poor prognosis of patients. Knockdown of miR-23a caused a notable reduction in the proliferation, migration and invasion of gastric cancer AGS cells. Sprouty homolog 2 (SPRY2) was then predicted to be target gene of miR-23a. A luciferase reporter gene assay data demonstrated that miR-23a has the ability to directly bind to the 3′-untranslational region of SPRY2 mRNA. Further investigation demonstrated that SPRY2 was significantly downregulated in gastric cancer tissues and cell lines, and the protein expression of SPRY2 was negatively regulated by miR-23a in AGS cells. Furthermore, knockdown of SPRY2 reduced the suppressive effects of miR-23a inhibition in AGS cell proliferation, migration and invasion. In addition, the activity of extracellular signal-regulated kinase (ERK) signaling was also inhibited by the miR-23a/SPRY2 knockdown in AGS cells. The present study indicated that miR-23a serves a promoting role in gastric cancer via targeting SPRY2 and downstream ERK signaling.

Apoptosis induction and cell cycle arrest induced by Sinkiangenone B, a novel phenylpropanoid derivative from the resin of Ferula sinkiangensis K. M. Shen

A new compound from Ferula sinkiangensis has the potential to treat gastric cancer through apoptosis induction and cell cycle arrest.

MicroRNA-34a directly targets high-mobility group box 1 and inhibits the cancer cell proliferation, migration and invasion in cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the second most common type of skin cancer with increasing incidence. In recent years, several microRNAs (miRs) have been demonstrated to serve an oncogenic or tumor suppressive role in CSCC. However, the exact role of miR-34a in CSCC and the underlying regulatory mechanism remain unclear. The present study aimed to investigate the regulatory mechanism of miR-34a in the malignant phenotypes of CSCC cells using MTT assay, wound healing assay and transwell assay. It was observed that miR-34a was significantly downregulated in CSCC tissues and cell lines, and low miR-34a expression was associated with the aggressive progression of CSCC. Restoration of miR-34a significantly suppressed the proliferation, migration and invasion of CSCC SCL-1 cells. High-mobility group box 1 (HMGB1) was then identified as a target gene of miR-34a in SCL-1 cells using bioinformatics prediction. The expression of HMGB1 was significantly upregulated in the CSCC tissues and cell lines. Furthermore, the protein expression of HMGB1 was negatively regulated by miR-34a in SCL-1 cells, while overexpression of HMGB1 impaired the inhibitory effects of miR-34a on SCL-1 cells. These findings suggest that miR-34a represses the malignant phenotypes of CSCC cells, at least partly, via the inhibition of HMGB1. Therefore, miR-34a may be used as a promising therapeutic candidate for CSCC.

miR-124 inhibits proliferation, migration and invasion of malignant melanoma cells via targeting versican

MicroRNA (miR)-124 has been implicated in malignant melanoma (MM). However, the detailed regulatory mechanism of miR-124 in the malignant phenotypes of MM cells has remained largely elusive. A total of 68 pairs of MM tissues and adjacent tissues were collected. Reverse-transcription quantitative polymerase chain reaction was used to examine the mRNA expression of versican as well as the expression of miR-124, and the protein expression of versican was assessed by western blot analysis. MTT, wound healing and Transwell assays were used to determine cell proliferation, migration and invasion, respectively. A bioinformatics analysis and a luciferase reporter assay were used to confirm the targeting association between miR-124 and versican. miR-124 was significantly downregulated in MM tissues compared with that in adjacent non-tumorous tissues, and decreased expression of miR-124 was associated with increased tumor thickness, advanced clinical stage and node metastasis of MM. Furthermore, the expression levels of miR-124 were also reduced in MM cell lines compared with normal human skin HACAT cells. Forced overexpression of miR-124 caused a significant reduction in the proliferation, migration and invasion of MM A375 cells. Versican was significantly upregulated in MM tissues and cell lines, and was identified as a novel target of miR-124 in A375 cells using a luciferase reporter gene assay, and miR-124 was revealed to negatively regulate the protein expression of versican in A375 cells. Overexpression of versican impaired the suppressive effects of miR-124 on the proliferation, migration and invasion of A375 cells. In conclusion, miR-124 inhibited the malignant phenotypes of MM cells at least partly via inhibition of versican. Therefore, the miR-124/versican axis may be used as a promising therapeutic target for inhibiting MM growth and metastasis.

Methylation-induced downregulation and tumor suppressive role of microRNA-29b in gastric cancer through targeting LASP1

MicroRNAs (miRs) have been demonstrated to play promoting or tumor suppressive roles in various human cancers, but the regulatory mechanism of miR-29b underlying gastric cancer development and progression still remains largely unclear. In the present study, we found that miR-29b was significantly downregulated in gastric cancer tissues and cell lines. Low expression of miR-29b was significantly associated with DNA methylation, and treatment with DNA methyltransferase inhibitor 5-Aza-20-deoxycytidine upregulated miR-29b in gastric cancer cells. In addition, both reduced miR-29b expression and miR-29b methylation were associated with disease progression and poor prognosis in gastric cancer. Restoration of miR-29b caused a reduction in gastric cancer cell proliferation, migration, and invasion, and inhibited tumor growth in vivo. LASP1 was then identified as a target gene of miR-29b in gastric cancer cells. Moreover, upregulation of LASP1 was significantly associated with gastric cancer progression and poor prognosis. Knockdown of LASP1 also suppressed the proliferation, migration, and invasion of gastric cancer cells. Moreover, overexpression of LASP1 impaired the suppressive effects of miR-29b on the malignant phenotypes of gastric cancer cells, suggesting that miR-29b may inhibit gastric cancer growth and metastasis via targeting LASP1. According to these data, miR-29b may be used as a potential therapeutic candidate for gastric cancer.

Targeting epithelial-mesenchymal plasticity in cancer: clinical and preclinical advances in therapy and monitoring

The concept of epithelial-mesenchymal plasticity (EMP), which describes the dynamic flux within the spectrum of phenotypic states that invasive carcinoma cells may reside, is being increasingly recognised for its role in cancer progression and therapy resistance. The myriad of events that are able to induce EMP, as well as the more recently characterised control loops, results in dynamic transitions of cancerous epithelial cells to more mesenchymal-like phenotypes through an epithelial-mesenchymal transition (EMT), as well as the reverse transition from mesenchymal phenotypes to an epithelial one. The significance of EMP, in its ability to drive local invasion, generate cancer stem cells and facilitate metastasis by the dissemination of circulating tumour cells (CTCs), highlights its importance as a targetable programme to combat cancer morbidity and mortality. The focus of this review is to consolidate the existing knowledge on the strategies currently in development to combat cancer progression via inhibition of specific facets of EMP. The prevalence of relapse due to therapy resistance and metastatic propensity that EMP endows should be considered when designing therapy regimes, and such therapies should synergise with existing chemotherapeutics to benefit efficacy. To further improve upon EMP-targeted therapies, it is imperative to devise monitoring strategies to assess the impact of such treatments on EMP-related phenomenon such as CTC burden, chemosensitivity/-resistance and micrometastasis in patients.

MicroRNA‑497 inhibits cellular proliferation, migration and invasion of papillary thyroid cancer by directly targeting AKT3

Thyroid cancer is the most common tumor of the endocrine organs. Emerging studies have indicated the critical roles of microRNAs (miRs) in papillary thyroid cancer (PTC) formation and progression through function as tumor suppressors or oncogenes. The present study investigated the expression level and biological roles of miR-497 in PTC and its underlying mechanisms. It was demonstrated that the expression level of miR-497 was reduced in both PTC tissues and cell lines. Enforced expression of miR-497 suppressed PTC cell proliferation, migration and invasion. According to bioinformatics analysis, a luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction and western blotting, RAC-γ serine/threonine-protein kinase (AKT3) was demonstrated to be the direct target gene of miR-497. In addition, AKT3 expression increased in PTC tissues and negatively correlated with miR-497 expression. Furthermore, downregulation of AKT3 also suppressed cell proliferation, migration and invasion of PTC, which had similar roles to miR-497 overexpression in PTC cells. Taken together, these results suggested that this newly identified miR-497/AKT3 signaling pathway may contribute to PTC occurrence and progression. These findings provide novel potential therapeutic targets for the therapy of PTC.

miR-663b promotes tumor cell proliferation, migration and invasion in nasopharyngeal carcinoma through targeting TUSC2

The authors' previous study revealed that the serum levels of microRNA (miR)-663b are significantly increased in patients with nasopharyngeal carcinoma (NPC), and are associated with NPC progression and poor prognosis. However, the molecular mechanism of underlying NPC growth and metastasis remains unclear. In the present study, quantitative polymerase chain reaction and western blot analyses were performed to examine changes to mRNA and protein expression, respectively. MTT, wound healing and Transwell assays were used to examine cell proliferation, migration and invasion, respectively. Luciferase reporter gene assays were performed to identify target genes of miR-663b. It was demonstrated that miR-663b was significantly upregulated in NPC tissue compared with non-tumor nasopharyngeal epithelial tissue samples. Furthermore, miR-663b expression gradually increased with advancing stages of NPC, with the highest expression being observed in the latest stage IV. The increased expression of miR-663b was associated with advanced clinical stage and lymph node metastasis. In addition, miR-663b expression was increased in NPC cell lines compared with normal nasopharyngeal epithelial NP69 cells. Knockdown of miR-663b resulted in a significant reduction in the proliferation, migration and invasion of NPC CNE1 cells. Tumor suppressor candidate 2 (TUSC2) was identified as a novel target gene of miR-663b. It was further demonstrated that TUSC2 was significantly downregulated in NPC tissue samples and cell lines. miR-663b negatively regulated the expression of TUSC2 at the post-transcriptional level in CNE1 cells. Additionally, inhibition of TUSC2 expression attenuated the suppressive effects of miR-663b downregulation on the proliferation, migration and invasion of CNE1 cells. To the best of our knowledge, this is the first study to demonstrate that miR-663b, which is upregulated in NPC, promotes the proliferation, migration and invasion of NPC cells, partially through the inhibition of TUSC2 expression. Therefore, it is suggested that miR-663b is a promising therapeutic target for the treatment of patients with NPC.

MiR-218 suppresses the metastasis and EMT of HCC cells via targeting SERBP1

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related deaths worldwide. Although many efforts for treating HCC have been made, the survival rate remains unsatisfied. Accumulating evidence indicates that microRNA-218 (miR-218) functions as a tumor suppressor and involves in many biological processes such as tumor initiation, development, and metastasis in certain types of human cancers. However, the potential function and underlying molecular mechanism of miR-218 in HCC still remains to be elucidated. Since HCC is a genetic disease, exploring the mechanisms of the pathogeny and integration are essential for the discovery of novel treatment targets for HCC. Therefore, the aim of the present study was to investigate the abnormal expression level of miR-218 in clinical HCC tissues and HCC cells, and to evaluate its function and underlying mechanisms in HCC. Our results revealed that miR-218 expression was significantly downregulated in HCC tissues and cell lines. Gain-of-function and loss-of-function assays indicated that forced expression of miR-218 in HCC cells inhibited cell migration/invasion and reversed epithelial-mesenchymal transition (EMT) to mesenchymal-epithelial transition (MET), while deletion of miR-218 promoted cell migration/invasion and contributed to the EMT phenotype formation. Bioinformatics analysis and luciferase reporter assay confirmed that serpine mRNA binding protein 1 (SERBP1) was a target gene of miR-218 and rescue assay further confirmed that SERBP1 involved in the function of miR-218 in HCC. All these results suggested that miR-218/SERBP1 signal pathway could inhibit the malignant phenotype formation and that targeting this pathway may be a potential novel way for HCC therapeutics.

MicroRNA-219-5p Represses the Proliferation, Migration, and Invasion of Gastric Cancer Cells by Targeting the LRH-1/Wnt/β-Catenin Signaling Pathway

MicroRNAs (miRNAs) are reportedly involved in gastric cancer development and progression. In particular, miR-219-5p has been reported to be a tumor-associated miRNA in human cancer. However, the role of miR-219-5p in gastric cancer remains unclear. In this study, we investigated for the first time the potential role and underlying mechanism of miR-219-5p in the proliferation, migration, and invasion of human gastric cancer cells. miR-219-5p was found to be markedly decreased in gastric cancer tissues and cell lines compared with adjacent tissues and normal gastric epithelial cells. miR-219-5p mimics or anti-miR-219-5p was transfected into gastric cancer cell lines to overexpress or suppress miR-219-5p expression, respectively. Results showed that miR-219-5p overexpression significantly decreased the proliferation, migration, and invasion of gastric cancer cells. Conversely, miR-219-5p suppression demonstrated a completely opposite effect. Bioinformatics and luciferase reporter assays indicated that miR-219-5p targeted the 3′-untranslated region of the liver receptor homolog-1 (LRH-1), a well-characterized oncogene. Furthermore, miR-219-5p inhibited the mRNA and protein levels of LRH-1. LRH-1 mRNA expression was inversely correlated with miR-219-5p expression in gastric cancer tissues. miR-219-5p overexpression significantly decreased the Wnt/β-catenin signaling pathway in gastric cancer cells. Additionally, LRH-1 restoration can markedly reverse miR-219-5p-mediated tumor suppressive effects. Our study suggests that miR-219-5p regulated the proliferation, migration, and invasion of human gastric cancer cells by suppressing LRH-1. miR-219-5p may be a potential target for gastric cancer therapy.