MALAT1/miR-124/Capn4 axis regulates proliferation, invasion and EMT in nasopharyngeal carcinoma cells

Identification of a lncRNA/circRNA-miRNA-mRNA network in Nasopharyngeal Carcinoma by deep sequencing and bioinformatics analysis

Background: Accumulating evidence indicates that non-coding RNAs (ncRNA), including long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), can function as competitive endogenous RNAs (ceRNAs) by binding to microRNAs (miRNAs) and regulating host gene expression at the transcriptional or post-transcriptional level. Dysregulation in ceRNA network regulation has been implicated in the occurrence and development of cancer. However, the lncRNA/circRNA-miRNA-mRNA regulatory network is still lacking in nasopharyngeal carcinoma (NPC). Methods: Differentially expressed genes (DEGs) were obtained from our previous sequencing data and Gene Expression Omnibus (GEO). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) were used to explore the biological functions of these common DEGs. Through a series of bioinformatic analyses, the lncRNA/circRNA-miRNA-mRNA network was established. In additional, the external data GSE102349 was used to test the prognostic value of the hub mRNAs through the Kaplan-Meier method. Results: We successfully constructed a lncRNA/circRNA-miRNA-mRNA network in NPC, consisting of 16 lncRNAs, 6 miRNAs, 3 circRNAs and 10 mRNAs and found that three genes (TOP2A, ZWINT, TTK) were significantly associated with overall survival time (OS) in patients. Conclusion: The regulatory network revealed in this study may help comprehensively elucidate the ceRNA mechanisms driving NPC, and provide novel candidate biomarkers for evaluating the prognosis of NPC.

MALAT-1 Is a Key Regulator of Epithelial-Mesenchymal Transition in Cancer: A Potential Therapeutic Target for Metastasis

Metastasis-associated lung adenocarcinoma transcript-1 (MALAT-1) is a long intergenic non-coding RNA (lncRNA) located on chr11q13. It is overexpressed in several cancers and controls gene expression through chromatin modification, transcriptional regulation, and post-transcriptional regulation. Importantly, MALAT-1 stimulates cell proliferation, migration, and metastasis and serves a vital role in driving the epithelial-to-mesenchymal transition (EMT), subsequently acquiring cancer stem cell-like properties and developing drug resistance. MALAT-1 modulates EMT by interacting with various intracellular signaling pathways, notably the phosphoinositide 3-kinase (PI3K)/Akt and Wnt/β-catenin pathways. It also behaves like a sponge for microRNAs, preventing their interaction with target genes and promoting EMT. In addition, we have used bioinformatics online tools to highlight the disparities in the expression of MALAT-1 between normal and cancer samples using data from The Cancer Genome Atlas (TCGA). Furthermore, the intricate interplay of MALAT-1 with several essential targets of cancer progression and metastasis renders it a good candidate for therapeutic interventions. Several innovative approaches have been exploited to target MALAT-1, such as short hairpin RNAs (shRNAs), antisense oligonucleotides (ASOs), and natural products. This review emphasizes the interplay between MALAT-1 and EMT in modulating cancer metastasis, stemness, and chemoresistance in different cancers.

Hsa_circ_0013561 promotes progression of nasopharyngeal carcinoma by activating JAK2/STAT3 signaling pathway

OBJECTIVE

Nasopharyngeal Carcinoma (NPC) is a malignancy of epithelium of epithelium of the nasopharynx, with the highest incidence of otolaryngeal malignancies. A growing number of studies confirm that Circular RNA (circRNA) plays an important role in tumor development, including Hsa_circ_0013561. This study aims to elucidate the process and mechanism of NPC regulation hsa_circ_0013561.

METHODS

In this study, circRNA expression nodes and subcellular localization in NPC tissues were analyzed by fluorescence in situ hybridization. The expression of hsa_circ_0013561 in NPC cells was further clarified by RT-qPCR. At the same time, the lentivirus vector interfered by hsa_circ_0013561 was constructed and transfected. The cell proliferation was detected by CCK-8 method, EdU assay and plate cloning assay. The cell cycle and apoptosis were detected by flow cytometry, and the cell migration ability was detected by wound healing assay and Transwell assay. Western blotting examined the expression of apoptosis, Epithelial-Mesenchymal Transition (EMT)-associated proteins, and Janus Kinase/Signal Transductor and Activator of Transcription (JAK/STAT) signaling pathway-related proteins.

RESULTS

The results showed that the expression of hsa_circ_0013561 in NPC samples was significantly upregulated and hsa_circ_0013561 localized in the cytoplasm. After down-regulating hsa_circ_0013561 expression, it significantly inhibited the proliferation and metastasis ability of NPC, inhibited EMT progression, and promoted apoptosis. Further studies showed that interference hsa_circ_0013561 significantly inhibited JAK2/STAT3 signaling pathway activation and induced the expression of apoptosis-related proteins.

CONCLUSION

In summary, we found that hsa_circ_0013561 is a pro-tumor circRNA in NPC, which can reduce the activation of JAK2/STAT3 pathway by knocking down hsa_circ_0013561, thereby slowing down the malignant progression of NPC. OXFORD CENTRE FOR EVIDENCE-BASED MEDICINE 2011 LEVELS OF EVIDENCE: Level 4.

Capn4 regulates Snail to promote the epithelial-mesenchymal transition of nasopharyngeal carcinoma by mediating the transcriptional activity of claudin-11

The metastasis and recurrence of nasopharyngeal carcinoma (NPC) contribute to the poor prognosis of patients. Inhibiting epithelial-mesenchymal transition (EMT) is an effective strategy to obstruct metastasis. Therefore, this study aimed to explore the effects of Capn4 on the EMT of NPC cells and its specific mechanism of action. The mRNA and protein expression levels of objective genes in NPC cell lines (5-8F and CNE-2) were evaluated by qRT-PCR and western blotting methods. The subcellular localization of Capn4 was detected by immunofluorescence (IF). Migration and invasion abilities of NPC cells were examined via wound-healing and trans-well methods, and the linkage between Snail and its downstream effector gene (claudin-11) was validated by chromatin immunoprecipitation (ChIP), dual-luciferase, and the yeast one-hybrid assays in series. Over-expression of Capn4 activated the PI3K/AKT signaling pathway and improved the expression of Snail, thus promoting the migration and invasion abilities of NPC cells. Mechanically, claudin-11 is one of the target genes in NPC cells that Snail regulates in a transcriptional regulatory manner. By blocking the regulatory axis of CAPN4/AKT/Snail/claudin-11 can significantly inhibit the invasion and metastasis of NPC cells. Capn4 promoted the EMT of NPC cells by activating the PI3K/AKT/Snail/claudin-11 axis, thereby promoting the malignant development of NPC. The Capn4/PI3K/AKT/Snail/claudin-11 axis might be a novel target to prevent NPC progression.

Regulation of the Inflammatory Response, Proliferation, Migration, and Epithelial-Mesenchymal Transition of Human Lens Epithelial Cells by the lncRNA-MALAT1/miR-26a-5p/TET1 Signaling Axis

Background

The ocular inflammatory microenvironment has been reported to be closely associated with the occurrence and progression of highly myopic cataract (HMC). Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) could alter the biological properties of mammalian cells by modulating the expression of inflammatory mediators; therefore, it may contribute to the development of HMC.

Objective

To investigate the function of MALAT1 in the inflammatory response, proliferation, migration, and epithelial-mesenchymal transition (EMT) of inflammatory and injured human lens epithelial cells (HLECs) and to reveal the underlying molecular signals.

Methods

Patients with HMC and age-related cataract (ARC) with an axial length of more than 26 mm were selected, and the anterior capsular tissue was obtained during cataract surgery. TNF-α (20 ng/mL) was chosen to induce inflammatory damage in HLECs to simulate the inflammatory microenvironment in HMC eyes. Specific siRNAs, inhibitors, and mimics were used to suppress or enhance the functions of MALAT1 and miR-26a-5p. RT-qPCR and Western blot analysis were performed to measure gene and protein expression, respectively.

Results

The expression of MALAT1 and the inflammatory mediators IL-6, MMP-2, and MMP-9 were significantly higher in HMC anterior capsule tissues than in ARC. TNF-α treatment increased the expression of MALAT1, while it also promoted the proliferation, migration, and EMT of HLECs. MALAT1 interference decreased the expression of IL-6 and MMP-2 and inhibited the aforementioned processes. Furthermore, MALAT1 negatively regulated the expression of miR-26a-5p and then promoted TET1 expression. TET1 was identified as a direct target of miR-26a-5p, and the promoting effect of MALAT1 on TET1 expression could be reversed by miR-26a-5p mimics.

Conclusion

The inflammatory environment and MALAT1 expression could be reciprocally induced in HLECs. MALAT1 may act as a ceRNA via the "sponge" miR-26a-5p and target TET1 to regulate the inflammatory response, proliferation, migration, and EMT processes in HLECs.

Regulation of the Key Epithelial Cancer Suppressor miR-124 Function by Competing Endogenous RNAs

A decrease in the miR-124 expression was observed in various epithelial cancers. Like a classical suppressor, miR-124 can inhibit the translation of multiple oncogenic proteins. Epigenetic mechanisms play a significant role in the regulation of miR-124 expression and involve hypermethylation of the MIR-124-1/-2/-3 genes and the effects of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) according to the model of competing endogenous RNAs (ceRNAs). More than 40 interactomes (lncRNA/miR-124/mRNA) based on competition between lncRNAs and mRNAs for miR-124 binding have been identified in various epithelial cancers. LncRNAs MALAT1, NEAT1, HOXA11-AS, and XIST are the most represented in these axes. Fourteen axes (e.g., SND1-IT1/miR-124/COL4A1) are involved in EMT and/or metastasis. Moreover, eight axes (e.g., OIP5-AS1/miR-124-5p/IDH2) are involved in key pathways, such as Wnt/b-catenin, E2F1, TGF-β, SMAD, ERK/MAPK, HIF-1α, Notch, PI3K/Akt signaling, and cancer cell stemness. Additionally, 15 axes impaired patient survival and three axes reduced chemo- or radiosensitivity. To date, 14 cases of miR-124 regulation by circRNAs have been identified. Half of them involve circHIPK3, which belongs to the exonic ecircRNAs and stimulates cell proliferation, EMT, autophagy, angiogenesis, and multidrug resistance. Thus, miR-124 and its interacting partners may be considered promising targets for cancer therapy.

LncRNA MALAT1 inhibits the proliferation and invasiveness of laryngeal squamous cell carcinoma Hep-2 cells by modulating miR-362-3p

OBJECTIVE

To investigate the mechanism of lncRNA MALAT1 (MALAT1) inhibiting the proliferation and invasiveness of laryngeal squamous cell carcinoma (LSCC) Hep-2 cells by modulating miR-362-3p.

METHODS

We collected the expression profile of lncRNAs and miRNAs in LSCC downloaded from The Cancer Genome Atlas (TCGA) database as well as LSCC tissue samples and adjacent normal counterparts resected from LSCC patients in Lvliang People's Hospital and First Hospital of Shanxi Medical University between January 2018 and June 2020 for analysis. Human LSCC Hep-2 cells were selected for experiments. The expression of miR-362-3p and MALAT1 was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cells were subsequently transfected to knock out MALAT1, and the growth, metastasis and invasiveness of cells were evaluated by CCK-8 assay, plate clone formation, wound healing, and Transwell invasion assays respectively. The binding of MALAT1 to miR-362-3p was verified by RNA pull-down, RNA binding protein immunoprecipitation (RIP), and dual-luciferase reporter assays.

RESULTS

MALAT1 was highly expressed while miR-362-3p was lowly expressed in both LSCC tissues and cells compared with normal counterparts. MALAT1 knockdown inhibited the viability of Hep-2 cells, reducing the number of plate clone-forming cells as well as the number of migrated and invaded cells. Transfection of miR-362-3p inhibitor into Hep-2 cells treated by si-MALAT1 reversed the inhibition of si-MALAT1 on the proliferation of Hep-2 cells, and promoted cell invasiveness and migration. MALAT1 can sponge miR-362-3p and inhibit its expression.

CONCLUSIONS

Knockdown of MALAT can inhibit Hep-2 cell proliferation and reduce its invasiveness and migration by modulating miR-362-3p.

miRNA‑124 regulates palmitic acid‑induced epithelial‑mesenchymal transition and cell migration in human retinal pigment epithelial cells by targeting LIN7C

The present study revealed that palmitic acid (PA) treatment induced epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells, which are involved in the progression of proliferative vitreoretinopathy (PVR). ARPE-19 cells were treated with PA followed by miRNA screening and EMT marker detection using qRT-PCR. Then, miR-124 mimic or inhibitor was transfected into ARPE-19 cells to explore the role of miR-124 on the EMT of ARPE-19 cells using transwell assay. The underlying mechanism of miRNA were predicted by bioinformatics method and confirmed by luciferase activity reporter assay. Furthermore, gain-of-function strategy was also used to explore the role of LIN7C in the EMT of ARPE-19 cells. The expression of miRNA or mRNA expression was determined by qRT-PCR and the protein expression was determined using western blot assay. The result presented that PA reduced the expression of E-cadherin/ZO-1 whilst increasing the expression of fibronectin/α-SMA. In addition, PA treatment enhanced the expression of microRNA (miR)-124 in ARPE-19 cells. Overexpression of miR-124 enhanced PA-induced upregulation of E-cadherin and ZO-1 expression and downregulation of fibronectin and α-SMA. Moreover, miR-124 mimic also enhanced the migration of ARPE-19 cells induced by PA treatment. Inversely, miR-124 inhibitor presented opposite effect on PA-induced EMT and cell migration in ARPE-19 cells. Luciferase activity reporter assay confirmed that Lin-7 homolog C (LIN7C) was a direct target of miR-124 in ARPE-19 cells. Overexpression of LIN7C was found to suppress the migration ability and expression of fibronectin and α-SMA, while increasing expression of E-cadherin and ZO-1; miR-124 mimic abrogated the inhibitive effect of LIN7C on the EMT of ARPE-19 cells and PA further enhanced this abolishment. Collectively, these findings suggest that miR-124/LIN7C can modulate EMT and cell migration in RPE cells, which may have therapeutic implications in the management of PVR diseases.

Major Role for Cellular MicroRNAs, Long Noncoding RNAs (lncRNAs), and the Epstein-Barr Virus-Encoded BART lncRNA during Tumor Growth In Vivo

This study assessed the effects of Epstein-Barr virus (EBV) and one form of virally encoded BART long noncoding RNAs (lncRNAs) on cellular expression in epithelial cells grown in vitro and as tumors in vivo determined by high-throughput RNA sequencing of mRNA and small RNAs. Hierarchical clustering based on gene expression distinguished the cell lines from the tumors and distinguished the EBV-positive tumors and the BART tumors from the EBV-negative tumors. EBV and BART expression also induced specific expression changes in cellular microRNAs (miRs) and lncRNAs. Multiple known and predicted targets of the viral miRs, the induced cellular miRs, and lncRNAs were identified in the altered gene set. The changes in expression in vivo indicated that the suppression of growth pathways in vivo reflects increased expression of cellular miRs in all tumors. In the EBV and BART tumors, many of the targets of the induced miRs were not changed and the seed sequences of the nonfunctional miRs were found to have homologous regions within the BART lncRNA. The inhibition of these miR effects on known targets suggests that these induced miRs have reduced function due to sponging by the BART lncRNA. This composite analysis identified the effects of EBV on cellular miRs and lncRNAs with a functional readout through identification of the simultaneous effects on gene expression. Major shifts in gene expression in vivo are likely mediated by effects on cellular noncoding RNAs. Additionally, a predicted property of the BART lncRNA is to functionally inhibit the induced cellular miRs.

The Epithelial-Mesenchymal Transition at the Crossroads between Metabolism and Tumor Progression

The transition between epithelial and mesenchymal phenotype is emerging as a key determinant of tumor cell invasion and metastasis. It is a plastic process in which epithelial cells first acquire the ability to invade the extracellular matrix and migrate into the bloodstream via transdifferentiation into mesenchymal cells, a phenomenon known as epithelial–mesenchymal transition (EMT), and then reacquire the epithelial phenotype, the reverse process called mesenchymal–epithelial transition (MET), to colonize a new organ. During all metastatic stages, metabolic changes, which give cancer cells the ability to adapt to increased energy demand and to withstand a hostile new environment, are also important determinants of successful cancer progression. In this review, we describe the complex interaction between EMT and metabolism during tumor progression. First, we outline the main connections between the two processes, with particular emphasis on the role of cancer stem cells and LncRNAs. Then, we focus on some specific cancers, such as breast, lung, and thyroid cancer.

MiRNA-124 regulates the sensitivity of renal cancer cells to cisplatin-induced necroptosis by targeting the CAPN4-CNOT3 axis

Background

Currently, drug-resistance is a major challenge in the treatment of renal cancer. Although microRNAs (miRNAs) have been reported to contribute to the incidence of drug resistance in renal cancer, the bio-functional roles and underlying regulatory mechanisms of novel miRNAs in cisplatin resistance remain largely unclear.

Methods

In this study, miRNA microarray analysis was applied to evaluate miRNA changes induced by cisplatin on RCC (renal cell carcinoma) cell lines. Then, Caki-1 and 786-0 cells were transfected with miR (miRNA)-124 mimics to observe cisplatin resistance in RCC cell lines after up-regulation of miR-124. TargetScan was used to identify putative protein-coding gene targets of miR-124. Further, the interaction between calpain small subunit 1 (Capn4) and CCR4-NOT transcription complex subunit 3 (CNOT3) was detected by quantitative real-time PCR (qPCR) and western blotting, and confirmed by co-immunoprecipitation. The effect of Capn4 and/or CNOT3 on cell viability and half maximal inhibitory concentration (IC50) value of miR-124 overexpressed Caki-1 and 786-O cells to cisplatin was evaluated using the Cell Counting Kit-8 (CCK-8) assay. And the effect of Capn4 and/or CNOT3 on the level of necroptosis in miR-124 overexpressed Caki-1 and 786-O cells to cisplatin was evaluated by flow cytometric analysis. Then, four groups of 786-0 cells (miR-124, miR-124+ Capn4, miR-124+ CNOT3, miR-124+ Capn4+ CNOT3) were inoculated into nude mice to observe the effect of cisplatin on tumor formation.

Results

miR-124 was found to be markedly elevated in renal cancer cells by cisplatin. Functionally, the overexpression of miR-124 reduced the sensitivity of renal cancer cells to cisplatin and CAPN4 was found to be a direct target of miR-124, which can negatively regulated CAPN4 expression. Moreover, ectopic expression of CAPN4 reversed the impairment of miR-124 on cisplatin-sensitivity and cisplatin-induced necroptosis. Mechanically, the present study revealed that CAPN4 could directly interact with CNOT3 and promote its degradation, and that the cisplatin-resistant phenotype was reversed by up-regulation of CNOT3.

Conclusions

Therefore, miR-124 is an important inhibitor in cisplatin-induced necroptosis, and the miR-124-CAPN4-CNOT3 signaling axis plays a critical role in the emergence of cisplatin-resistance.

The Role and Mechanism of MALAT1 Long Non-Coding RNA in the Diagnosis and Treatment of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the most common malignant tumor of the head and neck. HNSCC mainly affects the oral cavity and the laryngeal, laryngopharyngeal, and oropharyngeal tracts. The high incidence, hidden onset, low survival rate, and unsatisfactory effects of treatment effect underscore the importance of identify the mechanisms of HNSCC occurrence and development. Although there is a very urgent need for early diagnosis and treatment, there are currently no reliable early HNSCC diagnosis biomarkers or effective treatment targets. Long non-coding RNA (lncRNA) is widely involved in biological processes, especially as a key regulator of tumorigenesis and development. Lung adenocarcinoma metastasis-associated transcript 1 (MALAT1) is an important member of the lncRNA family that can regulate the occurrence and development of a variety of malignant tumors and is anticipated to be an ideal marker for early tumor diagnosis and an effective therapeutic target. Here, we review the research progress into the role of MALAT1 in the diagnosis and treatment of HNSCC and its regulatory mechanism.

MALAT1: A Promising Therapeutic Target for the Treatment of Metastatic Colorectal Cancer

Cancer metastasis research has emerged in recent years as one of the most important topics of debate in the discovery and development of novel anticancer therapies. Colorectal cancer (CRC), the third most common cancer worldwide, has a high mortality rate due to recurrence and distant metastasis to the liver. Several non-coding RNAs (ncRNAs) have been linked to metastatic CRC (mCRC), including the long non-coding RNA (lncRNA) Metastasis-Associated Lung-Adenocarcinoma Transcript 1 (MALAT1). MALAT1 is an RNA that has been linked to tumor cell proliferation, progression, epithelial-mesenchymal transition (EMT), cell migration and invasion, metastasis, and survival in mammalian species. Previously, there was no convincing evidence linking MALAT1 to mCRC. Studies have shown that MALAT1 functions as a competitive endogenous RNA (ceRNA) with microRNAs (miRNAs) and interacts directly with oncogenes and proteins. This RNA also activates several signaling pathways, including Wnt/β-catenin, PI3K/Akt/mTOR, and EMT. Meanwhile, standard chemotherapy and immunotherapy are the current treatment options for mCRC patients. However, evidence-based studies have recently demonstrated that inhibiting the MALAT1 RNA transcript can be considered as a treatment option for mCRC, highlighting the need to investigate its roles as a therapeutic target in mCRC. Thus, in this review, we looked at studies that linked MALAT1 to multiple signaling pathways implicated in mCRC, as well as its potential as a therapeutic target for the treatment of mCRC.

MicroRNA-124-3p inhibited progression of nasopharyngeal carcinoma by interaction with PCDH8 and the inactivation of PI3K/AKT/mTOR pathway

Nasopharyngeal carcinoma (NPC) is characterised by distinct geographical distribution and is particularly prevalent in Asian countries. But the mechanisms related to the progression of nasopharyngeal carcinoma (NPC) are not completely understood. MiR-124-3p functions as a tumor suppressor in many kinds of human cancers. Here, we explored the effects and mechanism of miR-124-3p on the proliferation and colony formation in NPC. In our study, we reported that miR-124-3p was significantly downregulated in NPC tissues and cell lines. Overexpression miR-124-3p decreased NPC cell proliferation and colony formation abilities. Meanwhile, knockdown miR-124-3p increased proliferation and colony formation abilities. Additionally, dual-luciferase assay showed that miR-124-3p could positively regulated PCDH8 by targeting its 3'-UTR. Overexpression of PCDH8 could partially rescue the proliferation and colony formation role of miR-124-3p inhibitor. Our study indicated that miR-124-3p played a tumor suppressor by directly interacting with PCDH8 and inhibiting the activation of the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) signaling pathway. Overall, we found that miR-124-3p inhibited the activation of the PI3K/AKT/mTOR signaling pathway in NPC by interacting with PCDH8. Thus, PCDH8 may be a potential molecular target that impeded NPC proliferation and colony formation.

Tumor Suppressive Effects of miR-124 and Its Function in Neuronal Development

MicroRNA-124 (miR-124) is strongly expressed in neurons, and its expression increases as neurons mature. Through DNA methylation in the miR-124 promoter region and adsorption of miR-124 by non-coding RNAs, miR-124 expression is known to be reduced in many cancer cells, especially with high malignancy. Recently, numerous studies have focused on miR-124 due to its promising tumor-suppressive effects; however, the overview of their results is unclear. We surveyed the tumor-suppressive effect of miR-124 in glial cell lineage cancers, which are the most frequently reported cancer types involving miR-124, and in lung, colon, liver, stomach, and breast cancers, which are the top five causes of cancer death. Reportedly, miR-124 not only inhibits proliferation and accelerates apoptosis, but also comprehensively suppresses tumor malignant transformation. Moreover, we found that miR-124 exerts its anti-tumor effects by regulating a wide range of target genes, most notably STAT3 and EZH2. In addition, when compared to the original role of miR-124 in neuronal development, we found that the miR-124 target genes that contribute to neuronal maturation share similarities with genes that cause cancer cell metastasis and epithelial-mesenchymal transition. We believe that the two apparently unrelated fields, cancer and neuronal development, can bring new discoveries to each other through the study of miR-124.

Long non-coding RNAs in nasopharyngeal carcinoma: biological functions and clinical applications

Nasopharyngeal carcinoma (NPC) is one of the most common head and neck malignancies. It has obvious ethnic and regional specificity. Long non-coding RNAs (LncRNAs) are a class of non-protein coding RNA molecules. Emerging research shows that lncRNAs play a key role in tumor development, prognosis, and treatment. With the deepening of sequence analysis, a large number of functional LncRNAs have been found in NPC, which interact with coding genes, miRNAs, and proteins to form a complex regulatory network. However, the specific role and mechanism of abnormally expressed lncRNAs in the pathogenesis of NPC is not fully understood. This article briefly introduced the concept, classification, and functional mechanism of lncRNAs and reviewed their biological functions and their clinical applications in NPC. Specifically, we described lncRNAs related to the occurrence, growth, invasion, metastasis, angiogenesis, and cancer stem cells of NPC; discussed lncRNAs related to Epstein-Barr virus infection; and summarized the role of lncRNAs in NPC treatment resistance. We have also sorted out lncRNAs related to Chinese medicine treatment. We believe that with the deepening of lncRNAs research, tumor-specific lncRNAs may become a new target for the treatment and a biomarker for predicting prognosis.

LncRNA LINC01503 aggravates the progression of cervical cancer through sponging miR-342-3p to mediate FXYD3 expression

Cervical cancer (CC), an aggressive malignancy, has a high risk of relapse and death, mainly occurring in females. Accumulating investigations have confirmed the critical role of long noncoding RNAs (lncRNAs) in diverse cancers. LncRNA LINC01503 has been reported as an oncogene in several cancers. Nonetheless, its role and molecular mechanism in CC have not been explored. In the present study, we found that FXYD3 expression was considerably up-regulated in CC tissues and cells. Moreover, FXYD3 deficiency conspicuously hampered cell proliferation and migration while facilitated cell apoptosis in CC cells. Subsequently, molecular mechanism experiments implied that FXYD3 was a downstream target gene of miR-342-3p, and FXYD3 expression was reversely mediated by miR-342-3p. Moreover, we discovered that LINC01503 acted as the endogenous sponge for miR-342-3p. Besides, LINC01503 negatively regulated miR-342-3p expression and positively regulated FXYD3 expression in CC. Rescue assays revealed that LINC01503 depletion-induced repression on CC progression could be partly recovered by miR-342-3p inhibition, and then the co-transfection of sh-FXYD3#1 rescued this effect. Conclusively, LINC01503 aggravated CC progression through sponging miR-342-3p to mediate FXYD3 expression, providing promising therapeutic targets for CC patients.

Long Non-Coding RNA CRYBG3 Promotes Lung Cancer Metastasis via Activating the eEF1A1/MDM2/MTBP Axis

The occurrence of distant tumor metastases is a major barrier in non-small cell lung cancer (NSCLC) therapy, and seriously affects clinical treatment and patient prognosis. Recently, long non-coding RNAs (lncRNAs) have been demonstrated to be crucial regulators of metastasis in lung cancer. The aim of this study was to reveal the underlying mechanisms of a novel lncRNA LNC CRYBG3 in regulating NSCLC metastasis. Experimental results showed that LNC CRYBG3 was upregulated in NSCLC cells compared with normal tissue cells, and its level was involved in these cells' metastatic ability. Exogenously overexpressed LNC CRYBG3 increased the metastatic ability and the protein expression level of the metastasis-associated proteins Snail and Vimentin in low metastatic lung cancer HCC827 cell line. In addition, LNC CRYBG3 contributed to HCC827 cell metastasis in vivo. Mechanistically, LNC CRYBG3 could directly combine with eEF1A1 and promote it to move into the nucleus to enhance the transcription of MDM2. Overexpressed MDM2 combined with MDM2 binding protein (MTBP) to reduce the binding of MTBP with ACTN4 and consequently increased cell migration mediated by ACTN4. In conclusion, the LNC CRYBG3/eEF1A1/MDM2/MTBP axis is a novel signaling pathway regulating tumor metastasis and may be a potential therapeutic target for NSCLC treatment.

Regulation of Long Non-Coding RNAs by Plant Secondary Metabolites: A Novel Anticancer Therapeutic Approach

Simple Summary

Cancer is caused by the rapid and uncontrolled growth of cells that eventually lead to tumor formation. Genetic and epigenetic alterations are among the most critical factors in the onset of carcinoma. Phytochemicals are a group of natural compounds that play an essential role in cancer prevention and treatment. Long non-coding RNAs (lncRNAs) are potential therapeutic targets of bioactive phytochemicals, and these compounds could regulate the expression of lncRNAs directly and indirectly. Here, we critically evaluate in vitro and in vivo anticancer effects of phytochemicals in numerous human cancers via regulation of lncRNA expression and their downstream target genes.

Abstract

Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs that play an essential role in various cellular activities, such as differentiation, proliferation, and apoptosis. Dysregulation of lncRNAs serves a fundamental role in the progression and initiation of various diseases, including cancer. Precision medicine is a suitable and optimal treatment method for cancer so that based on each patient’s genetic content, a specific treatment or drug is prescribed. The rapid advancement of science and technology in recent years has led to many successes in this particular treatment. Phytochemicals are a group of natural compounds extracted from fruits, vegetables, and plants. Through the downregulation of oncogenic lncRNAs or upregulation of tumor suppressor lncRNAs, these bioactive compounds can inhibit metastasis, proliferation, invasion, migration, and cancer cells. These natural products can be a novel and alternative strategy for cancer treatment and improve tumor cells’ sensitivity to standard adjuvant therapies. This review will discuss the antineoplastic effects of bioactive plant secondary metabolites (phytochemicals) via regulation of expression of lncRNAs in various human cancers and their potential for the treatment and prevention of human cancers.

Long Non-coding RNAs in Gammaherpesvirus Infections: Their Roles in Tumorigenic Mechanisms

Long non-coding RNAs (lncRNAs) regulate gene expression at the epigenetic, transcriptional, or posttranscriptional level by interacting with protein, DNA, and RNA. Emerging evidence suggests that various lncRNAs are abnormally expressed and play indispensable roles in virus-triggered cancers. Besides, a growing number of studies have shown that virus-encoded lncRNAs participate in tumorigenesis. However, the functions of most lncRNAs in tumors caused by oncogenic viruses and their underlying mechanisms remain largely unknown. In this review, we summarize current findings regarding lncRNAs involved in cancers caused by Epstein–Barr virus (EBV) and Kaposi’s sarcoma herpesvirus (KSHV). Additionally, we discuss the contribution of lncRNAs to tumor occurrence, development, invasion, and metastasis; the roles of lncRNAs in key signaling pathways and their potential as biomarkers and therapeutic targets for tumor diagnostics and treatment.

An update on the role of miR-124 in the pathogenesis of human disorders

MicroRNA-124 (miR-124) is a copious miRNA in the brain, but it is expressed in a wide range of human/animal tissues participating in the pathogenesis of several disorders. Based on its important function in the development of the nervous system, abnormal expression of miR-124 has been detected in nervous system diseases including Alzheimer's disease, Parkinson's disease, Hypoxic-Ischemic Encephalopathy, Huntington's disease, and ischemic stroke. In addition to these conditions, miR-124 contributes to the pathogenesis of cardiovascular disorders, hypertension, and atherosclerosis. Besides, it has been shown to be down-regulated in a wide range of human cancers such as colorectal cancer, breast cancer, gastric cancer, glioma, pancreatic cancer, and other types of cancer. Yet, few studies have reported upregulation of miR-124 in some cancer types. In the current study, we describe the role of miR-124 in these malignant and non-malignant conditions.

The roles of miRNAs and lncRNAs in Epstein-Barr virus associated epithelial cell tumors

Epstein-Barr virus (EBV) infection is highly prevalent in the population and is known to be associated with a variety of human tumors, such as nasopharyngeal carcinoma, gastric cancer, and lymphoma; however, the mechanisms of EBV carcinogenesis remain unclear. Recent studies have revealed that many non-coding RNAs participate in the regulation of proliferation, migration, invasion, and other processes in EBV-associated tumor, and the interaction between ncRNAs and the potential target genes has gradually become a research hotspot. Therefore, here, we discuss the expression and roles of ncRNAs in EBV-associated epithelial tumors.

Regulatory Networks of LncRNA MALAT-1 in Cancer

Long noncoding (lnc)RNAs are a group of RNAs with a length greater than 200 nt that do not encode a protein but play an essential role in regulating the expression of target genes in normal biological contexts as well as pathologic processes including tumorigenesis. The lncRNA metastasis-associated lung adenocarcinoma transcript (MALAT)-1 has been widely studied in cancer. In this review, we describe the known functions of MALAT-1; its mechanisms of action; and associated signaling pathways and their clinical significance in different cancers. In most malignancies, including lung, colorectal, thyroid, and other cancers, MALAT-1 functions as an oncogene and is upregulated in tumors and tumor cell lines. MALAT-1 has a distinct mechanism of action in each cancer type and is thus at the center of large gene regulatory networks. Dysregulation of MALAT-1 affects cellular processes such as alternative splicing, epithelial–mesenchymal transition, apoptosis, and autophagy, which ultimately results in the abnormal cell proliferation, invasion, and migration that characterize cancers. In other malignancies, such as glioma and endometrial carcinoma, MALAT-1 functions as a tumor suppressor and thus forms additional regulatory networks. The current evidence indicates that MALAT-1 and its associated signaling pathways can serve as diagnostic or prognostic biomarker or therapeutic target in the treatment of many cancers.

miR-331-3p Inhibits Proliferation and Promotes Apoptosis of Nasopharyngeal Carcinoma Cells by Targeting elf4B-PI3K-AKT Pathway

BACKGROUND

The incidence of nasopharyngeal carcinoma is increasing gradually, but the pathogenesis is not completely clear. MicroRNA, a highly conserved endogenous noncoding small molecule RNA, plays an essential role in the regulation of gene expression and is a hotspot in cancer research worldwide.

OBJECTIVES

Although previous studies have confirmed that the abnormal expression of microRNAs is closely related to the progression of nasopharyngeal carcinoma, the role of miRNA-331-3p in nasopharyngeal carcinoma has not been studied. The purpose of this study was to explore the role and mechanism of miRNA-331-3p in the progression of nasopharyngeal carcinoma.

MATERIALS AND METHODS

Real-time quantitative reverse transcription polymerase chain reaction was performed to detect the expression of miRNA-331-3p in nasopharyngeal carcinoma clinical samples and cell lines (CNE-1 and 5-8F cells). After overexpression of miRNA-331-3p in CNE-1 cells, cell proliferation was measured by Cell Counting Kit-8 assay, cell invasion was detected by Transwell assay, and apoptosis was tested by flow cytometry. In addition, the dual-luciferase reporter assay was used to identify the target gene of miRNA-331-3p and Western blotting was performed to measure the relative protein expression.

RESULTS

The expression of miRNA-331-3p in nasopharyngeal carcinoma clinical samples and cells was decreased significantly. Overexpression of miRNA-331-3p markedly inhibited the proliferation and invasion of CNE-1 cells and promoted cell apoptosis. Moreover, overexpression of miRNA-331-3p reduced the expression of target gene elF4B, leading to inhibition of the phosphorylation of Phosphoinositide 3-kinase (PI3K) and Serine/ threonine kinase (AKT).

CONCLUSION

miRNA-331-3p inhibited cell proliferation and induced cell apoptosis in nasopharyngeal carcinoma by targeting elF4B gene and then blocked the PI3K-AKT signaling pathway.

SIGNIFICANCE

The role of miRNA-331-3p in the development of NPC and its mechanism provide new ideas for the treatment of nasopharyngeal carcinoma.

The HMGB1-2 Ovarian Cancer Interactome. The Role of HMGB Proteins and Their Interacting Partners MIEN1 and NOP53 in Ovary Cancer and Drug-Response

High mobility group box B (HMGB) proteins are overexpressed in different types of cancers such as epithelial ovarian cancers (EOC). We have determined the first interactome of HMGB1 and HMGB2 in epithelial ovarian cancer (the EOC-HMGB interactome). Libraries from the SKOV-3 cell line and a primary transitional cell carcinoma (TCC) ovarian tumor were tested by the Yeast Two Hybrid (Y2H) approach. The interactome reveals proteins that are related to cancer hallmarks and their expression is altered in EOC. Moreover, some of these proteins have been associated to survival and prognosis of patients. The interaction of MIEN1 and NOP53 with HMGB2 has been validated by co-immunoprecipitation in SKOV-3 and PEO1 cell lines. SKOV-3 cells were treated with different anti-tumoral drugs to evaluate changes in HMGB1, HMGB2, MIEN1 and NOP53 gene expression. Results show that combined treatment of paclitaxel and carboplatin induces a stronger down-regulation of these genes in comparison to individual treatments. Individual treatment with paclitaxel or olaparib up-regulates NOP53, which is expressed at lower levels in EOC than in non-cancerous cells. On the other hand, bevacizumab diminishes the expression of HMGB2 and NOP53. This study also shows that silencing of these genes affects cell-viability after drug exposure. HMGB1 silencing causes loss of response to paclitaxel, whereas silencing of HMGB2 slightly increases sensitivity to olaparib. Silencing of either HMGB1 or HMGB2 increases sensitivity to carboplatin. Lastly, a moderate loss of response to bevacizumab is observed when NOP53 is silenced.

Capn4 contributes to tumor invasion and metastasis in gastric cancer via activation of the Wnt/β-catenin/MMP9 signalling pathways

Capn4, a small regulatory subunit of the calpain proteolytic system, functions as a potential tumor promoter in several cancers. However, the biological functions and molecular mechanisms of Capn4 in gastric cancer (GC) remain poorly understood. In the current study, we found that upregulation of Capn4 was detected frequently in GC tissues, and was associated with significantly worse survival among the GC patients. Multivariate analyses revealed that abundance of Capn4 was an independent predictive marker for the poor prognosis of GC. Further, Capn4 knockdown notably suppressed GC invasion and metastasis in vitro. Consistently, a xenograft assay showed that silencing of Capn4 in GC cells suppressed their dissemination to lung tissue in vivo. Moreover, our results indicated that Capn4 promotes gastric cancer metastasis by increasing MMP9 expression, and demonstrated that MMP9 is crucial for the pro-metastasis role of Capn4 in GC cells. Further investigation revealed that Capn4 regulated MMP9 expression via activation of Wnt/β-catenin signaling pathway. Mechanistically, we found that Capn4 can decreased β-catenin ubiquitination to enhance the protein stability of β-catenin in GC cells. Collectively, Capn4 has a central role in gastric cancer metastasis, which could be a potential diagnostic and therapeutic target for GC.

Multiple Mechanisms Involving in Radioresistance of Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is the malignant tumor with ethnic and geographical distribution preference. Although intensity-modulated radiotherapy (IMRT)-based radiotherapy combined with chemotherapy and targeted therapy has dramatically improved the overall survival of NPC patients, there are still some patients suffering from recurrent tumors and the prognosis is poor. Multiple mechanisms may be responsible for radioresistance of NPC, such as cancer stem cells (CSCs) existence, gene mutation or aberrant expression of genes, epigenetic modification of genes, abnormal activation of certain signaling pathways, alteration of tumor microenvironment, stress granules (SGs) formation, etc. We conduct a comprehensive review of the published literatures focusing on the causes of radioresistance, retrospect the regulation mechanisms following radiation, and discuss future directions of overcoming the resistance to radiation.

Calpain Small Subunit 1 Protein in the Prognosis of Cancer Survivors and Its Clinicopathological Correlation

Background/Aims. Calpain small subunit 1 (Capn4) is implicated in tumorigenesis and plays a key role in multiple tumors. This study aimed to fully illustrate the prognostic value of Capn4 protein in cancer patients.

Long noncoding RNA cytoskeleton regulator RNA promotes cell invasion and metastasis by titrating miR-613 to regulate ANXA2 in nasopharyngeal carcinoma

Background

Nasopharyngeal carcinoma (NPC) is one of the most frequent head and neck malignant tumors. Long noncoding RNAs play critical roles in tumorigenesis.

Methods

Real‐time quantitative PCR arrays were used to evaluate the expression levels of cytoskeleton regulator RNA (CYTOR) in NPC tissues and cells. Cell counting kit‐8 and colony formation analyses were used to test the NPC cell viability, while wound healing and transwell assays were employed to detect cell invasion and migration ability. Luciferase reporter assay and Western blot analyses were employed to explore the relationships among CYTOR, miR‐613, and ANXA2.

Results

We found that CYTOR expression was elevated both in NPC tissues and cells. Functional assays revealed that CYTOR promoted the invasion and migration of NPC cells. The established spontaneous lymph node metastasis model also confirmed that CYTOR promoted NPC cell metastasis in vivo. Mechanically, we found that the subcellular localization of CYTOR mostly occurred in the cell cytoplasm. Luciferase reporter and RIP assays confirmed that CYTOR functioned as the molecular sponge of miR‐613. Subsequent experiments confirmed that ANXA2 was directly targeted by miR‐613. Gain‐ and loss‐of‐function studies further confirmed that CYTOR induced the upregulation of ANXA2 by competitively binding to miR‐613, thus leading to NPC metastasis.

Conclusion

Our results highlight the importance of CYTOR in NPC development and provide new insights into potential therapeutic targets for NPC.

Silencing of long noncoding RNA SRRM2-AS exerts suppressive effects on angiogenesis in nasopharyngeal carcinoma via activating MYLK-mediated cGMP-PKG signaling pathway

Long noncoding RNAs (lncRNAs) play a crucial role in several malignances, involving nasopharyngeal carcinoma (NPC), a heterogeneous disease. This study investigated mechanism of serine/arginine repetitive matrix protein 2-alternative splicing (SRRM2-AS) in NPC cell proliferation, differentiation, and angiogenesis. Initially, differentially expressed lncRNAs were screened out via microarray analysis. Vascular endothelial growth factor (VEGF) protein positive rate and microvessel density (MVD) were determined in NPC and adjacent tissues. NPC CNE-2 cells were treated with a series of vector and small interfering RNA to explore the effect of SRRM2-AS in NPC. The target relationship between myosin light chain kinase (MYLK) and SRRM2-AS was verified. Levels of SRRM2-AS, MYLK, cGMP, PKG, VEGF, PCNA, Ki-67, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and Caspase 3 were determined after transfection. Finally, the effect of SRRM2-AS on cell proliferation, colony formation, angiogenesis, cell cycle, and apoptosis in NPC was evaluated. SRRM2-AS was highly expressed and MYLK was poorly expressed in NPC tissues. VEGF protein positive rate and MVD were elevated in NPC tissues. MYLK was confirmed to be a target gene of SRRM2-AS. Silencing of SRRM2-AS elevated levels of MYLK, cGMP, PKG, Bax, and Caspase 3, but decreased levels of VEGF, PCNA, Ki-67, and Bcl-2. Especially, silencing of SRRM2-AS suppressed cell proliferation, colony formation and angiogenesis, blocked cell cycle, and enhanced cell apoptosis in NPC. Our results suggested that silencing of SRRM2-AS protected against angiogenesis of NPC cells by upregulating MYLK and activating the cGMP-PKG signaling pathway, which provides a new target for NPC treatment.

Metastasis Associated Lung Adenocarcinoma Transcript 1: An update on expression pattern and functions in carcinogenesis

The Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is among long non-coding RNAs (lncRNAs) which has disapproved the old term of "junk DNA" which was used for majority of human genome which are not transcribed to proteins. An extensive portion of literature points to the fundamental role of this lncRNA in tumorigenesis process of diverse cancers ranging from solid tumors to leukemia. Being firstly identified in lung cancer, it has prognostic and diagnostic values in several cancer types. Consistent with the proposed oncogenic roles for this lncRNA, most of studies have shown up-regulation of MALAT1 in malignant tissues compared with non-malignant/normal tissues of the same source. However, few studies have shown down-regulation of MALAT1 in breast cancer, endometrial cancer, colorectal cancer and glioma. In the current study, we have conducted a comprehensive literature search and provided an up-date on the role of MALAT1 in cancer biology. Our investigation underscores a potential role as a diagnostic/prognostic marker and a putative therapeutic target for MALAT1.

LncRNA SOX2-OT regulates proliferation and metastasis of nasopharyngeal carcinoma cells through miR-146b-5p/HNRNPA2B1 pathway

Nasopharyngeal carcinoma (NPC) is an aggressive malignancy with a high mortality on account of its frequent metastasis and poor prognosis. An extensive body of investigations has proven that long noncoding RNAs are implicated in a variety of biological processes. Although SOX2-OT has been reported to play an oncogenic role in osteosarcoma, the mechanism of SOX2-OT-driven NPC progression is still obscure. The aim of this study was to elucidate the biological function of SOX2-OT and the related possible mechanism in NPC. In our study, SOX2-OT was notably elevated in NPC samples and cells. Further, a high expression level of SOX2-OT was correlated with poor clinical outcomes of NPC. Results from loss-of-function experiments suggested that knockdown of SOX2-OT repressed cell proliferation, arrested cell cycle, facilitated cell apoptosis, and inhibited cell metastasis of NPC. To further investigate the molecular mechanism of SOX2-OT, miR-146b-5p was found to directly bind to SOX2-OT, which mediated the role of SOX2-OT in NPC tumorigenesis. In addition, HNRNPA2B1 was a target of miR-146b-5p and SOX2-OT modulated the expression of HNRNPA2B1 through competitively binding to miR-146b-5p. At last, we discovered that SOX2-OT regulated NPC progression by targeting miR-146b-5p/HNRNPA2B1 pathway, which may provide more innovative targets for the treatment of patients with NPC.

MicroRNA-124 regulates TRAF6 expression and functions as an independent prognostic factor in colorectal cancer

An increasing number of studies have confirmed that miR-124 exhibits a suppressive role in glioblastoma, cervical cancer and breast cancer; however, the function of miR-124 in colorectal cancer (CRC) has not been completely elucidated. In the present study, miR-124 expression was confirmed by reverse transcription-quantitative PCR in 80 colorectal tissues and para-cancerous tissues. The influence of altered miR-124 expression was analyzed by statistical approaches including Cox multivariate regression analysis and the Kaplan-Meier method, and the target genes of miR-124 were confirmed by luciferase reporter assays. Immunohistochemical techniques were also performed in order to measure the expression levels of target proteins. miR-124 expression was observed to be decreased in colorectal tissue samples, and this phenomenon was correlated with adverse clinical indicators and poor patient survival time. Luciferase reporter assays indicated that miR-124 directly regulated TNF receptor associated factor 6 (TRAF6) 3′-untranslated region (UTR). Hence, it was proposed that miR-124 dysregulation may negatively influence the expression of TRAF6 and therefore serve as a biomarker of epithelial-mesenchymal transition in CRC tissues. In summary, the present study demonstrated that miR-124 regulates the expression of TRAF6, and may potentially function as an independent prognostic factor and therapeutic target in patients with CRC.

miR-429 suppresses cell proliferation, migration and invasion in nasopharyngeal carcinoma by downregulation of TLN1

Background

miR-429 and TLN1 have been shown to affect the biological behaviours of many carcinomas. However, their effects in nasopharyngeal carcinoma (NPC) are not yet clear. Here, we investigated their regulatory relationships and effects on NPC cells.

Methods

TargetScan was used to predict the regulatory relationships of miR-429 and TLN1 in NPC cells. Then, Western blotting and quantitative real-time PCR (qPCR) were performed to examine TLN1 levels, and qPCR was used to determine miR-429 levels in NPC cell lines with different metastatic characteristics (5-8F, CNE-2, CNE-1, 6-10B and NP69), to investigate whether TLN1 and miR-429 are correlated with the metastatic characteristics of these cells. Next, we upregulated or downregulated miR-429 in 5-8F and 6-10B cells, which have different tumourigenicity and transferability, and examined TLN1 expression by western blotting and qPCR after transfection. QPCR was also performed to confirm successful transfection of miR-429 mimic into 5-8F and 6-10B cells. Dual luciferase reporter gene assay was performed to investigate whether miR-429 regulates TLN1 by binding to its 3′UTR. After transfection, Cell Counting Kit-8 (CCK8) and IncuCyte were used to examine the proliferation of these cells, and wound-healing assay, Transwell migration assay, and invasion assays were performed to investigate the changes in migration and invasion after transfection.

Results

Western blotting and qPCR analyses showed that the protein level of TLN1 was negatively correlated with miR-429 in NPC cell lines (P < 0.05), while the mRNA level showed no relation with miR429 expression (P > 0.05). In addition, cells with high transferability showed high TLN1 expression at the protein level, while miR429 expression showed the opposite trend (P < 0.05), but there were no differences at the mRNA level between the different cell lines. Overexpression of miR429 in 5-8F and 6-10B cells was accompanied by downregulation of TLN1 at the protein level (P < 0.05), while there were no significant differences at the mRNA level (P > 0.05). In addition, transferability, proliferation, and invasion were downregulated by miR429 overexpression (P < 0.05). However, dual-luciferase reporter gene assay indicated that TLN1 was not a direct target of miR-429.

Conclusion

This study showed that miR-429 functions as a tumour suppressor in NPC by downregulation of TLN1, although the relationship is not direct.

Long Noncoding RNA MALAT1 Acts as a Competing Endogenous RNA to Regulate TGF-β2 Induced Epithelial-Mesenchymal Transition of Lens Epithelial Cells by a MicroRNA-26a-Dependent Mechanism

The aim of the present study was to characterize whether the long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/miR-26a/Smad4 axis is involved in epithelial–mesenchymal transition (EMT) of lens epithelial cells (LECs). Primary human LECs were separated and cultured. Microarray analysis showed that a total of 568 lncRNAs are differentially expressed in primary HLECs in the presence of TGF-β2 and MALAT1 is mostly significantly dysregulated lncRNAs, which is increased by nearly 17-fold. In addition, upregulation of MALAT1 and downregulation of miR-26a were detected in human posterior capsule opacification (PCO) attached LECs and the LECs obtained from patients with anterior polar cataracts by quantitative RT-PCR (qRT-PCR). Next, our results showed that TGF-β2 induces overexpression of EMT markers in primary HLECs via a MALAT1-dependent mechanism. The mechanism is that MALAT1 negatively regulates miR-26a and miR-26a directly targets Smad4 by luciferase reporter assays and RNA-binding protein immunoprecipitation assay. In summary, TGF-β2 induces MALAT1 overexpression, which in turn MALAT1 acts as a ceRNA targeting Smad4 by binding miR-26a and promotes the progression of EMT of LECs.

Keratin 6A gene silencing suppresses cell invasion and metastasis of nasopharyngeal carcinoma via the β‑catenin cascade

Nasopharyngeal carcinoma (NPC) is a type of head and neck cancer. This study aimed to study the mechanisms of ectopic keratin 6A (KRT6A) in NPC. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were performed to detect KRT6A levels in NPC cell lines (C666-1, 5-8F and SUNE-1) and a nasopharyngeal epithelial cell line (NP69, as a control). After SUNE-1 NPC cells had been silenced by KRT6A, cell viability, metastasis and invasion were determined using Cell Counting Kit-8, wound healing and Transwell assays, respectively. KRT6A levels, metastasis-associated factors and the Wnt/β-catenin pathway were measured using RT-qPCR and western blotting. It was demonstrated that KRT6A was upregulated in all detected NPC cells, among which KRT6A was the highest in SUNE-1 cells. In SUNE-1 cells, cell viability was inhibited at 24 and 48 h, and that cell metastasis and invasion were demonstrated to be suppressed by KRT6A silencing. Both the mRNA and protein levels of KRT6A, matrix metalloproteinase (MMP)-2, MMP-9, β-catenin, lymphoid enhancer binding factor 1 and T-cell specific factor 4 were reduced in the small interfering (si)KRT6A group. However, the results demonstrated that the levels of epithelial-cadherin and tissue inhibitor of metalloproteinase-2 (TIMP-2) were promoted in the siKRT6A group. The activation of the Wnt/β-catenin pathway by lithium chloride reversed the effect of si-KRT6A by modulating the expression of MMP-2/9 and TIMP2. It was observed that KRT6A silencing suppressed cell invasion and metastasis of NPC via the β-catenin cascade. Together these results provide important insights into a novel approach for the diagnosis and treatment of NPC.

LncRNA MALAT1 modulates ox-LDL induced EndMT through the Wnt/β-catenin signaling pathway

Background

Endothelial-to-mesenchymal transition (EndMT) plays significant roles in atherosclerosis, but the regulatory mechanisms involving lncRNAs remain to be elucidated. Here we sort to identify the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in ox-LDL-induced EndMT.

Methods

The atherosclerosis model was established by feeding ApoE^−/− mice with high-fat diet, and the levels of lncRNA MALAT1 in mouse arterial tissue were detected by RT-qPCR. Cell model was established by treating human umbilical vein endothelial cells (HUVECs) with ox-LDL, and the levels of EndMT markers, such as CD31, vWF, α-SMA and Vimentin and lncRNA MALAT1 levels were detected and their correlations were analyzed. The role of MALAT1 in EndMT and its dependence on Wnt/β-catenin signaling pathway was further detected by knocking down or overexpressing MALAT1.

Results

MALAT1 was upregulated in high-fat food fed ApoE^−/− mice. HUVECs treated with ox-LDL showed a significant decrease in expression of CD31 and vWF, a significant increase in expression of α-SMA and vimentin, and upregulated MALAT1. An increased MALAT1 level facilitated the nuclear translocation of β-catenin induced by ox-LDL. Inhibition of MALAT1 expression reversed nuclear translocation of β-catenin and EndMT. Moreover, overexpression of MALAT1 enhanced the effects of ox-LDL on HUVEC EndMT and Wnt/β-catenin signaling activation.

Conclusions

Our study revealed that the pathological EndMT required the activation of the MALAT1-dependent Wnt/β-catenin signaling pathway, which may be important for the onset of atherosclerosis.

Trial registration

Not applicable.

Knockdown of long non-coding RNA SNHG5 inhibits malignant cellular phenotypes of glioma via Wnt/CTNNB1 signaling pathway

Objective: Human brain glioma is the most malignant primary intracranial tumor, which has poor prognosis and high mortality. Long noncoding RNAs are considered to take part in cellular phenotypes and are emerging as diagnostic and prognostic biomarkers of glioma. This study will research the effects of Small Nucleolar RNA Host Gene 5 (SNHG5) gene on malignant cellular phenotypes in glioma and explore the possible mechanisms. Materials and Methods: The expression level of SNHG5 was examined using quantitative Real-time PCR in glioma tissues and cell lines. Loss-of-function experiments of SNHG5 together with Enhanced Cell Counting Kit-8, flow cytometry and cell invasion assay were used to investigate the effects of SNHG5 on malignant cellular phenotypes of glioma cells. Finally, luciferase assay and western blotting were applied to determine the activity of WNT/CTNNB1 signaling pathway. Results: SNHG5 gene was high-expressed in glioma tissues and cell lines. Knockdown of SNHG5 gene depressed cell proliferation and invasiveness as well as promoted the apoptosis of U251 and U87 cells. In addition, online database analysis showed SNHG5 was closely related to Wnt/CTNNB1 signaling pathway. Knockdown of SNHG5 inactivated Wnt/CTNNB1 signaling pathway, and the activating of Wnt/CTNNB1 signaling pathway partly restored the influences of SNHG5 knockdown on malignant cellular phenotypes of U251 and U87 cells. Conclusion: SNHG5 gene was high-expressed in glioma, knockdown of SNHG5 inhibits malignant cellular phenotypes of glioma via Wnt/CTNNB1 signaling pathway.

LncRNA ZFAS1 promotes proliferation and migration and inhibits apoptosis in nasopharyngeal carcinoma via the PI3K/AKT pathway in vitro

BACKGROUND

Increasing evidence shows that long non-coding RNAs (lncRNAs) play a key role in the development of various cancers. Zinc finger antisense 1 (ZFAS1) is a novel lncRNA with previously demonstrated associations with several types of cancer. Here we examined the expression and potential function of the ZFAS1 in nasopharyngeal carcinoma (NPC).

METHODS

We detected ZFAS1 expression in GSE12452, a human microarray dataset, and NPC cell lines. Small interfering RNA against ZFAS1 was used to elucidate the cellular functions of ZFAS1 using MTT, colony formation, cell cycle, cell apoptosis, transwell invasion and migration and western blot assays. An activator of the PI3K/AKT signaling pathway (740Y-P) was used to determine the contribution of PI3K/AKT.

RESULTS

ZFAS1 was significantly upregulated in NPC tissues and cell lines. Silencing ZFAS1 significantly inhibited cell proliferation and invasion, arrested cell cycle progression and promoted cell apoptosis, as well as reduced epithelial-mesenchymal transition. Moreover, 740Y-P could rescue the effects of ZFAS1 knockdown on proliferation, apoptosis and invasion in 5-8F cells.

CONCLUSIONS

ZFAS1 might play an oncogenic role in NPC and facilitate cell proliferation and invasion via the PI3K/AKT signaling pathway in NPC cells.

Capn4 promotes esophageal squamous cell carcinoma metastasis by regulating ZEB1 through the Wnt/β-catenin signaling pathway

BACKGROUND

Capn4 and ZEB1 play important roles in the metastasis of several types of cancer. However, the roles and relationship of Capn4 and ZEB1 in esophageal squamous cell carcinoma (ESCC) remain unclear.

METHODS

ESCC tumor tissues and corresponding normal esophageal epithelial tissues were obtained from 86 patients undergoing resection surgery at the Department of General Surgery, First Affiliated Hospital of Chinese PLA General Hospital from 2012 to 2017. Cell migration and invasion were examined via quantitative real-time PCR and Western blot assay.

RESULTS

Our results indicate that both Capn4 and ZEB1 are significantly upregulated in ESCC tissues compared to corresponding adjacent tissues, and a positive correlation between expression and associated malignant characteristics was found. Silencing of Capn4 expression markedly inhibited ESCC invasion and metastasis in vitro and in vivo, and was accompanied by decreased ZEB1 expression. Furthermore, the anti-metastasis role of Capn4 silencing was reversed by ZEB1 overexpression, whereas knockdown of ZEB1 decreased ESCC metastasis driven by the upregulation of Capn4. Mechanistically, Capn4 regulated ZEB1 expression via activation of the Wnt/β-catenin signaling pathway in ESCC cells.

CONCLUSION

Overall, our results show that enhanced Capn4 expression activates the Wnt/β-catenin signaling pathway, resulting in increased ZEB1 expression and the promotion of ESCC cell metastasis.

The regulatory network of nasopharyngeal carcinoma metastasis with a focus on EBV, lncRNAs and miRNAs

Metastasis of nasopharyngeal carcinoma (NPC) remains a main cause of death for NPC patients even though great advances have been made in therapeutic approaches. An in-depth study into the molecular mechanisms of NPC metastasis will help us combat NPC. Epstein-Barr virus (EBV) infection is an evident feature of nonkeratinizing NPC and is strongly associated with tumor metastasis. Recently, long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have become a hot topic of research due to their epigenetic regulatory roles in NPC metastasis. The EBV products, lncRNAs and miRNAs can target each other and share several common signaling pathways, which form an interconnected, complex molecular regulatory network. In this review, we discuss the features of this regulatory network and summarize the molecular mechanisms of NPC metastasis, focusing on EBV, lncRNAs and miRNAs with updated knowledge.

The long non-coding RNA CRNDE competed endogenously with miR-205 to promote proliferation and metastasis of melanoma cells by targeting CCL18

Melanoma was the most malignant skin neoplasm with an increasing morbidity around the world. Although new immunotherapies and targeted therapies have emerged recently, the long-term survival of melanoma patients still remains low. To reveal effective diagnostic methods and therapeutic strategies, the potential mechanism of melanoma is urgently needed to be studied. Long non-coding RNAs (lncRNAs) have become an important regulatory factor in the occurrence and development of cancer, and it can be used as a new prognostic and diagnostic marker. In this study, we aimed to inspect the effects of lncRNA colorectal neoplasia differentially expressed (CRNDE) on the melanoma cell viability, invasion and migration. After microarray analysis, 106 dysregulated lncRNAs and 1187 abnormally expressed mRNAs were screened out. Further, the lncRNA CRNDE and CCL18 expression in melanoma tissues and cell lines were examined. It was determined that they were both overexpressed in melanoma tissues and cell lines. The down-regulation of lncRNA CRNDE and CCL18 induced melanoma cell apoptosis and inhibited cell viability. Then, miR-205 which had binding site with lncRNA CRNDE and CCL18 was involved in the next experiment, and it was down-regulated in melanoma that negatively correlated with lncRNA CRNDE expression. In addition, overexpression of miR-205 results in the restore of cell viability and aggressiveness. In conclusion, LncRNA CRNDE promotes the migration and invasion of melanoma by sponging miR-205 and releasing CCL18.

MALAT1-miR663a negative feedback loop in colon cancer cell functions through direct miRNA-lncRNA binding

The lncRNA MALAT1 has multiple biological functions, including influencing RNA processing, miRNA sponging, and cancer development. It is acknowledged that miR663a and its targets are inflammation-related genes frequently deregulated in many cancers. The associations between MALAT1 and miR663a and their target genes remain unknown. In this study, it was found that in colon cancer (CC) cells, MALAT1 and miR663a were reciprocally repressed in cDNA array screening and qRT-PCR analysis. However, MALAT1 was significantly upregulated in CC tissues, and miR663a was significantly downregulated relative to the corresponding surgical margin (SM) tissues. An inverse relationship between MALAT1 and miR663a expression was detected among CC tissue samples (n = 172, r = -0.333, p < 0.0001). The RNA-pulldown results showed MALAT1 lncRNA-miR663a binding. The results of luciferase-reporter analysis further revealed that the MALAT1 7038-7059 nt fragment was the miR663a seed sequence. Both miR663a knockdown and MALAT1 activation alone significantly upregulated the expression levels of miR663a targets, including TGFB1, PIK3CD, P53, P21, and JUND, in the CC cell lines HCT116 and SW480. A positive relationship was also observed between the expression levels of MALAT1 and these miR663a targets in the above 172 CC samples and 160 CC samples in publicly available databases. In addition, reciprocal abolishment of the effects of miR663a overexpression and MALAT1 activation on the proliferation, migration, and invasion of cancer cells was also observed, while miR663a upregulation and MALAT1 activation alone inhibited and promoted the behaviors of these CC cell lines, respectively. All these suggested that, as a competing endogenous lncRNA, MALAT1 maybe a dominant protector for the degradation of miR663a targets. miR663a and MALAT1 may consist of a negative feedback loop to determine their roles in CC development.

Association of twelve polymorphisms in three onco-lncRNA genes with hepatocellular cancer risk and prognosis: A case-control study

AIM

To evaluate the association of 12 tag single nucleotide polymorphisms (tagSNPs) in three onco-long non-coding RNA (lncRNA) genes (HOTTIP, CCAT2, MALAT1) with the risk and prognosis of hepatocellular cancer (HCC).

METHODS

Twelve tagSNPs covering the three onco-lncRNAs were genotyped by the KASP method in a total of 1338 samples, including 521 HCC patients and frequency-matched 817 controls. The samples were obtained from an unrelated Chinese population at the First Hospital of China Medical University from 2012-2015. The expression quantitative trait loci (eQTL) analyses were conducted to explore further the potential function of the promising SNPs.

RESULTS

Three SNPs in HOTTIP, one promoter SNP in MALAT1, and one haplotype of HOTTIP were associated with HCC risk. The HOTTIP rs17501292, rs2067087, and rs17427960 SNPs were increased to 1.55-, 1.20-, and 1.18-fold HCC risk under allelic models (P = 0.012, 0.017 and 0.049, respectively). MALAT1 rs4102217 SNP was increased to a 1.32-fold HCC risk under dominant models (P = 0.028). In addition, the two-way interaction of HOTTIP rs17501292-MALAT1 rs619586 polymorphisms showed a decreased effect on HCC risk (P_interaction = 0.028, OR = 0.30) and epistasis with each other. HOTTIP rs3807598 variant genotype showed significantly longer survival time in HBV negative subgroup (P = 0.049, HR = 0.12), and MALAT1 rs591291 showed significantly better prognosis in female and HBV negative subgroups (P = 0.022, HR = 0.37; P = 0.042, HR = 0.25, respectively). In the study, no significant effect was observed in eQTL analysis.

CONCLUSION

Specific lncRNA (HOTTIP and MALAT1) SNPs have potential to be biomarkers for HCC risk and prognosis.

NRP1 promotes cell migration and invasion and serves as a therapeutic target in nasopharyngeal carcinoma

Neuropilin 1 (NRP1) promotes tumor growth, angiogenesis, tumor migration, and invasion. Its higher expression is closely related to the metastasis and poor outcome of many cancers. We have reported that NRP1 was expressed at higher levels in highly metastatic cells in comparison to minimally metastatic cells in nasopharyngeal carcinoma (NPC). However, the role of NRP1 in NPC cell migration and invasion is still unclear, and whether it could serve as a potential therapeutic target for patients with NPC still needs further investigation. In this study, our results demonstrated that ectopic expression of NRP1 in S26 and 6-10B cells promoted cell migration and invasion via wound healing and transwell assays. In contrast, knockdown of NRP1 in HONE1, CNE1 and S18 cells through Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) technology suppressed cell migration and invasion. Moreover, we found that EG00229, a small molecule inhibitor of NRP1, significantly suppressed NRP1-mediated promotion of NPC cells migration and invasion. Mechanistically, we demonstrated that NRP1 promoted migration and invasion by decreasing E-cadherin levels and increasing N-cadherin levels. Collectively, our results showed that NRP1 promotes cell migration and invasion and could function as a promising target for the future treatment of patients with NPC.

The emerging co-regulatory role of long noncoding RNAs in epithelial-mesenchymal transition and the Warburg effect in aggressive tumors

Malignant tumor cells have several unique characteristics, and their ability to undergo epithelial-mesenchymal transition (EMT) is a molecular gateway to invasive behavior. Rapid proliferation and increased invasiveness during EMT enhance aberrant glucose metabolism in tumor cells. Meanwhile, aerobic glycolysis provides energy, biosynthesis precursors, and an appropriate microenvironment to facilitate EMT. Reciprocal crosstalk between the processes synergistically contributes to malignant cancer behaviors, but the regulatory mechanisms underlying this interaction remain unclear. Long non-coding RNAs (lncRNAs) are a recently recognized class of RNAs involved in multiple physiological and pathological tumor activities. Increasing evidence indicates that lncRNAs play overlapping roles in both EMT and cancer metabolism. In this review, we describe the lncRNAs reportedly involved in the two biological processes and explore the detailed mechanisms that could help elucidate this co-regulatory network and provide a theoretical basis for clinical management of EMT-related malignant phenotypes.