Long noncoding RNA BC032469, a novel competing endogenous RNA, upregulates hTERT expression by sponging miR-1207-5p and promotes proliferation in gastric cancer

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

Impact of MICA 3'UTR allelic variability on miRNA binding prediction, a bioinformatic approach

MicroRNAs (miRNAs) are small non-coding RNAs that participate as powerful genetic regulators. MiRNAs can interfere with cellular processes by interacting with a broad spectrum of target genes under physiological and pathological states, including cancer development and progression. Major histocompatibility complex major histocompatibility complex class I-related chain A (MICA) belongs to a family of proteins that bind the natural-killer group 2, member D (NKG2D) receptor on Natural Killer cells and other cytotoxic lymphocytes. MICA plays a crucial role in the host's innate immune response to several disease settings, including cancer. MICA harbors various single nucleotide polymorphisms (SNPs) located in its 3'-untranslated region (3'UTR), a characteristic that increases the complexity of MICA regulation, favoring its post-transcriptional modulation by miRNAs under physiological and pathological conditions. Here, we conducted an in-depth analysis of MICA 3'UTR sequences according to each MICA allele described to date using NCBI database. We also systematically evaluated interactions between miRNAs and their putative targets on MICA 3'UTR containing SNPs using in silico analysis. Our in silico results showed that MICA SNPs rs9266829, rs 1880, and rs9266825, located in the target sequence of miRNAs hsa-miR-106a-5p, hsa-miR-17-5p, hsa-miR-20a-5p, hsa-miR-20b-5p, hsa-miR-93, hsa-miR-1207.5p, and hsa-miR-711 could modify the binding free energy between -8.62 and -18.14 kcal/mol, which may affect the regulation of MICA expression. We believe that our results may provide a starting point for further exploration of miRNA regulatory effects depending on MICA allelic variability; they may also be a guide to conduct miRNA in silico analysis for other highly polymorphic genes.

Telomerase and hallmarks of cancer: An intricate interplay governing cancer cell evolution

Transformed cells must acquire specific characteristics to be malignant. Weinberg and Hanahan characterize these characteristics as cancer hallmarks. Though these features are independently driven, substantial signaling crosstalk in transformed cells efficiently promotes these feature acquisitions. Telomerase is an enzyme complex that maintains telomere length. However, its main component, Telomere reverse transcriptase (TERT), has been found to interact with various signaling molecules like cMYC, NF-kB, BRG1 and cooperate in transcription and metabolic reprogramming, acting as a strong proponent of malignant features such as cell death resistance, sustained proliferation, angiogenesis activation, and metastasis, among others. It allows cells to avoid replicative senescence and achieve endless replicative potential. This review summarizes both the canonical and noncanonical functions of TERT and discusses how they promote cancer hallmarks. Understanding the role of Telomerase in promoting cancer hallmarks provides vital insight into the underlying mechanism of cancer genesis and progression and telomerase intervention as a possible therapeutic target for cancer treatment. More investigation into the precise molecular mechanisms of telomerase-mediated impacts on cancer hallmarks will contribute to developing more focused and customized cancer treatment methods.

Hypoxia-responsive lncRNA G077640 promotes ESCC tumorigenesis via the H2AX-HIF1α-glycolysis axis

Long noncoding RNAs (lncRNAs) contribute to esophageal squamous cell carcinoma (ESCC) progression, but the underlying mechanisms remain elusive. In this study, we verified a hitherto uncharacterized hypoxia-responsive lncRNA, G077640, which is upregulated in human ESCC cells and tissues, supporting the proliferation and migration of ESCC cells. Mechanistically, G077640 prevented hypoxia-inducible factor-1α (HIF1α) from being degraded by directly interacting with histone H2AX and further modulated the interaction of HIF1α and H2AX. In addition, G077640 reprogrammed glycolytic metabolism by regulating the expression of glucose transporter 4 (GLUT4), hexokinase 2 (HK2) and pyruvate dehydrogenase kinase 1 (PDK1) for ESCC proliferation and migration. Clinically, G077640 was associated with poor prognosis in ESCC patients. Taken together, our findings identified a hypoxia-responsive lncRNA that contributes to ESCC cells proliferation and migration, and targeting G077640 and its pathway might be a potential therapeutic strategy for ESCC.

MiR-200/183 family-mediated module biomarker for gastric cancer progression: an AI-assisted bioinformatics method with experimental functional survey

BACKGROUND

Gastric cancer (GC) is a major cancer burden throughout the world with a high mortality rate. The performance of current predictive and prognostic factors is still limited. Integrated analysis is required for accurate cancer progression predictive biomarker and prognostic biomarkers that help to guide therapy.

METHODS

An AI-assisted bioinformatics method that combines transcriptomic data and microRNA regulations were used to identify a key miRNA-mediated network module in GC progression. To reveal the module's function, we performed the gene expression analysis in 20 clinical samples by qRT-PCR, prognosis analysis by multi-variable Cox regression model, progression prediction by support vector machine, and in vitro studies to elaborate the roles in GC cells migration and invasion.

RESULTS

A robust microRNA regulated network module was identified to characterize GC progression, which consisted of seven miR-200/183 family members, five mRNAs and two long non-coding RNAs H19 and CLLU1. Their expression patterns and expression correlation patterns were consistent in public dataset and our cohort. Our findings suggest a two-fold biological potential of the module: GC patients with high-risk score exhibited a poor prognosis (p-value < 0.05) and the model achieved AUCs of 0.90 to predict GC progression in our cohort. In vitro cellular analyses shown that the module could influence the invasion and migration of GC cells.

CONCLUSIONS

Our strategy which combines AI-assisted bioinformatics method with experimental and clinical validation suggested that the miR-200/183 family-mediated network module as a "pluripotent module", which could be potential marker for GC progression.

An Updated Review of Contribution of Long Noncoding RNA-NEAT1 to the Progression of Human Cancers

Long non-coding RNAs (lncRNAs) present pivotal roles in cancer tumorigenesis and progression. Recently, nuclear paraspeckle assembly transcript 1 (NEAT1) as a lncRNA has been shown to mediate cell proliferation, migration, and EMT in tumor cells. NEAT1 by targeting several miRNAs/mRNA axes could regulate cancer cell behavior. Therefore, NEAT1 may function as a potent biomarker for the prediction and treatment of some human cancers. In this review, we summarized various NEAT1-related signaling pathways that are critical in cancer initiation and progression.

Tetramethylpyrazine Inhibits the Proliferation and Invasion of Glioma Cells by Regulating the UBL7-AS1/miR-144-3p Pathway

This work aims to investigate the effects of tetramethylpyrazine (TMP) on the proliferation, migration, and invasion of glioma cells and to analyze the regulation mechanism of TMP on the long noncoding RNA UBL7-AS1/miR-144-3p pathway. Glioma cell line and normal astrocytes were collected. The expression of UBL7-AS1 was detected by real-time PCR. The glioma cells were overexpressed with UBL7-AS1. CCK-8 and Transwell assays were used to detect cell proliferation and cell invasion ability, respectively. Bioinformatics was adopted to predict the possible regulatory mechanisms of UBL7-AS1. The dual luciferase reporter gene was applied to verify the regulatory effect of RNA UBL7-AS1 with miR-144-3p. TMP inhibited the proliferation and invasion of glioma cells. UBL7-AS1 was highly expressed in glioma tissues and cells. The overexpression of UBL7-AS1 promotes the cell proliferation and invasion of glioma. UBL7-AS1 can act as a sponge for miR-144-3p in glioma cells. The overexpression of UBL7-AS1 can reverse the inhibition of TMP on proliferation, migration, and invasion of glioma cells. TMP inhibits the proliferation, migration, and invasion of glioma cells by regulating the UBL7-AS1/miR-144-3p pathway.

Novel biomarkers of microRNAs in gastric cancer; an overview from diagnosis to treatment

The fourth frequent disease in the world and the second cause of cancer-related death is gastric cancer (GC). In this way, over 80% of diagnoses are made in the middle to advanced degrees of the disease, underscoring the requirement for innovative biomarkers that can be identified quickly. Meaningly, biomarkers that can complement endoscopic diagnosis and be used to detect patients with a high risk of GC are desperately needed. These biomarkers will allow for the accurate prediction of therapy response and prognosis in GC patients, as well as the development of an optimal treatment strategy for each individual. Conspicoiusly, microRNAs (miRNAs) and small noncoding RNA regulates the expression of target mRNA and thereby modifies critical biological mechanisms. According to the data, abnormally miRNAs expression in GC is linked to tumor growth, carcinogenesis, aggression and distant metastasis. Importantly, miRNA expression patterns and next-generation sequencing (NGS) can also be applied to analyze kinds of tissues and cancers. Given the high death rates and poor prognosis of GC, and the absence of a clinical diagnostic factor that is adequately sensitive to GC, research into novel sensitive and specific markers for GC diagnosis is critical. In this review,we evaluate the latest research findings that suggest the feasibility and clinical utility of miRNAs in GC.

LncRNA THRIL promotes high glucose-induced proliferation and migration of human retina microvascular endothelial cells through enhancing autophagy

AIMS

Diabetes retinopathy (DR) is associated with retinal microvascular system injury induced by high glucose (HG). This study aims to explore the role and mechanism of long non-coding RNA THRIL in regulating cell proliferation and migration of human retina microvascular endothelial cells (hRMECs) under HG condition.

METHOD

The gene and protein expression were detetced by RT-PCR and western blot, respectively. Cell proliferation and migration of hRMECs were examined using MTT assay and Transwell assay, respectively. The interaction between miR-125b-5p and THRIL or autophagy-related gene 4D (ATG4D) was analyzed using luciferase activity assay.

RESULTS

THRIL expression was induced by HG in hRMECs. THRIL overexpression enhanced the proliferation and migration of hRMECs induced by HG, whereas THRIL silencing yielded the opposite results. Furthermore, THRIL overexpression induced autophagy activation, and inhibition of autophagy by 3-methyladenine abrogated the promotory effects of THRIL overexpression on cell proliferation and migration of hRMECs. Mechanismly, THRIL inhibited miR-125b-5p to upregulate the expression of ATG4D (an important autophagy-related gene), thereby promoting autophagy. Moreover, miR-125b-5p overexpression or ATG4D silencing alone abolished the promoting effects of THRIL overexpression on HG-induced autophagy, proliferation and migration of hRMECs.

CONCLUSIONS

THRIL promotes HG-induced cell proliferation and migration of hRMECs through activation of autophagy via the miR-125b-5p/ATG4D axis. THRIL may serve as a potential therapeutic target for DR.

The novel lncRNA GPC5-AS1 stabilizes GPC5 mRNA by competitively binding with miR-93/106a to suppress gastric cancer cell proliferation

Long non-coding RNAs (lncRNAs) are of importance in the genesis and progression of gastric cancer (GC). GPC5-AS1 is a novel lncRNA associated with methyl-CpG-binding protein 2 (MeCP2), identified in our previous microarray analysis; however, the role of GPC5-AS1 in GC remains unknown. In the present study, we demonstrate that GPC5-AS1 is downregulated in GC cells and tissues, and this aberrant expression is regulated by MeCP2 through CpG site binding in the promoter region. Importantly, we also demonstrate that GPC5-AS1 overexpression suppresses cell proliferation, colony formation, and cell cycle transition; induces apoptosis in vitro; and inhibits tumorigenicity in vivo. The expression of the controversial gene GPC5 was downregulated in GC tissues, and elevated GPC5 level could inhibit GC cell growth. Mechanistically, we demonstrated that GPC5-AS1 stabilizes GPC5 mRNA by acting as a molecular sponge for miR-93 and miR-106a, thereby reducing GC tumor progression. In conclusion, our results suggest that GPC5-AS1 may play a pivotal role in GC and serve as a potential diagnostic biomarker and a powerful therapeutic target for GC.

Telomerase in Cancer: Function, Regulation, and Clinical Translation

Simple Summary

Cells undergoing malignant transformation must circumvent replicative senescence and eventual cell death associated with progressive telomere shortening that occurs through successive cell division. To do so, malignant cells reactivate telomerase to extend their telomeres and achieve cellular immortality, which is a “Hallmark of Cancer”. Here we review the telomere-dependent and -independent functions of telomerase in cancer, as well as its potential as a biomarker and therapeutic target to diagnose and treat cancer patients.

Abstract

During the process of malignant transformation, cells undergo a series of genetic, epigenetic, and phenotypic alterations, including the acquisition and propagation of genomic aberrations that impart survival and proliferative advantages. These changes are mediated in part by the induction of replicative immortality that is accompanied by active telomere elongation. Indeed, telomeres undergo dynamic changes to their lengths and higher-order structures throughout tumor formation and progression, processes overseen in most cancers by telomerase. Telomerase is a multimeric enzyme whose function is exquisitely regulated through diverse transcriptional, post-transcriptional, and post-translational mechanisms to facilitate telomere extension. In turn, telomerase function depends not only on its core components, but also on a suite of binding partners, transcription factors, and intra- and extracellular signaling effectors. Additionally, telomerase exhibits telomere-independent regulation of cancer cell growth by participating directly in cellular metabolism, signal transduction, and the regulation of gene expression in ways that are critical for tumorigenesis. In this review, we summarize the complex mechanisms underlying telomere maintenance, with a particular focus on both the telomeric and extratelomeric functions of telomerase. We also explore the clinical utility of telomeres and telomerase in the diagnosis, prognosis, and development of targeted therapies for primary, metastatic, and recurrent cancers.

Insights Into the Molecular Mechanisms of Late Flowering in Prunus sibirica by Whole-Genome and Transcriptome Analyses

Freezing during the flowering of Prunus sibirica is detrimental to fruit production. The late flowering (LF) type, which is delayed by 7-15 days compared with the normal flowering (NF) type, avoids damages at low temperature, but the molecular mechanism of LF remains unclear. Therefore, this study was conducted to comprehensively characterize floral bud differentiation. A histological analysis showed that initial floral bud differentiation was delayed in the LF type compared to the NF type. Genome-wide associated studies (GWAS) showed that a candidate gene (PaF106G0600023738.01) was significantly associated with LF type. It was identified as trehalose-6-phosphate phosphatase (PsTPPF), which is involved in trehalose-6-phosphate (Tre6P) signaling pathway and acts on floral transition. A whole-transcriptome RNA sequencing analysis was conducted, and a total of 6,110 differential expression (DE) mRNAs, 1,351 DE lncRNAs, and 148 DE miRNAs were identified. In addition, 24 DE mRNAs related with floral transition were predicted, and these involved the following: three interactions between DE lncRNAs and DE mRNAs of photoperiod pathway with two mRNAs (COP1, PaF106G0400018289.01 and CO3, MXLOC_025744) and three lncRNAs (CCLR, LTCONS_00031803, COCLR1, LTCONS_00046726, and COCLR2, LTCONS_00046731); one interaction between DE miRNAs and DE mRNAs with one mRNA, encoding trehalose-6-phosphate synthase (PsTPS1, PaF106G0100001132.01), and one miRNA (miRNA167h). Combined with the expression profiles and Tre6P levels, functions of PsTPPF and PsTPS1 in Tre6P regulation were considered to be associated with flowering time. A new network of ceRNAs correlated with LF was constructed, and it consisted of one mRNA (PsTPS1), one lncRNA (TCLR, LTCONS_00034157), and one miRNA (miR167h). This study provided insight into the molecular regulatory mechanism of LF in Prunus sibirica.

A Novel Ferroptosis-Related Gene Risk Signature for Predicting Prognosis and Immunotherapy Response in Gastric Cancer

Background

Gastric cancer (GC) is the third leading cause of cancer death worldwide with complicated molecular and cellular heterogeneity. Iron metabolism and ferroptosis play crucial roles in the pathogenesis of GC. However, the prognostic role and immunotherapy biomarker potential of ferroptosis-related genes (FRGs) in GC still remains to be clarified.

Methods

We comprehensively analyzed the prognosis of different expression FRGs, based on gastric carcinoma patients in the TCGA cohort. The functional enrichment and immune microenvironment associated with these genes in gastric cancer were investigated. The prognostic model was constructed to clarify the relation between FRGs and the prognosis of GC. Meanwhile, the ceRNA network of FRGs in the prognostic model was performed to explore the regulatory mechanisms.

Results

Gastric carcinoma patients were classified into the A, B, and C FRGClusters with different features based on 19 prognostic ferroptosis-related differentially expressed genes in the TCGA database. To quantify the FRG characteristics of individual patients, FRGScore was constructed. And the research shows the GC patients with higher FRGScore had worse survival outcome. Moreover, thirteen prognostic ferroptosis-related differentially expressed genes (DEGs) were selected to construct a prognostic model for GC survival outcome with a superior accuracy in this research. And we also found that FRG RiskScore can be an independent biomarker for the prognosis of GC patients. Interestingly, GC patients with lower RiskScore had less immune dysfunction and were more likely to respond to immunotherapy according to TIDE value analysis. Finally, a ceRNA network based on FRGs in the prognostic model was analyzed to show the concrete regulation mechanisms.

Conclusions

The ferroptosis-related gene risk signature has a superior potent in predicting GC prognosis and acts as the biomarkers for immunotherapy, which may provide a reference in clinic.

Integrative analysis of long non-coding RNAs and mRNAs associated with tumorigenesis of salivary gland pleomorphic adenoma

OBJECTIVE

The current study investigated long non-coding RNA (lncRNA) and mRNA profiles of the human salivary gland pleomorphic adenoma (SGPA).

DESIGN

Microarray analysis was used to study the expression of lncRNAs and mRNAs and the differentially expressed lncRNAs in human SGPA (all from parotid gland) were identified. The differentially expressed lncRNAs were subjected to qRT-PCR to verify and quantify their expression and a lncRNA-mRNA co-expression network was constructed. The lncRNAs correlated to pleomorphic adenoma gene 1 (PLAG1), a known key transcription factor, were identified and analyzed.

RESULTS

In the present study, 17,382 lncRNAs and 8132 mRNAs were found to be significantly differentially expressed in SGPA (fold change > 2, P < 0.05). The expression of three lncRNAs (NR_110874, NR_110875 and T087085) was significantly altered in SGPA compared to the corresponding healthy tissues, and it was confirmed using the lncRNA-mRNA co-expression network analysis that several lncRNAs interact with 5 key regulators (PLAG1, CTNNB1, CCND1, IGF2, and TP53). Furthermore, T042819 was significantly upregulated in SGPA, which may upregulate PLAG1 by sponging has-miR195-5p.

CONCLUSION

These data suggested that the differently expressed lncRNAs may contribute to the tumorigenesis of SGPA, and analyzing the differences in the lncRNA expression profiles may provide novel insights into the pathogenesis of SGPA.

LncRNA Hmrhl regulates expression of cancer related genes in chronic myelogenous leukemia through chromatin association

Long non-coding RNA has emerged as a key regulator of myriad gene functions. One such lncRNA mrhl, reported by our group, was found to have important role in spermatogenesis and embryonic development in mouse. Recently, its human homolog, Hmrhl was shown to have differential expression in several type of cancers. In the present study, we further characterize molecular features of Hmrhl and gain insight into its functional role in leukemia by gene silencing and transcriptome-based studies. Results indicate its high expression in CML patient samples as well as in K562 cell line. Silencing experiments suggest role of Hmrhl in cell proliferation, migration & invasion. RNA-seq and ChiRP-seq data analysis further revealed its association with important biological processes, including perturbed expression of crucial TFs and cancer-related genes. Among them ZIC1, PDGRFβ and TP53 were identified as regulatory targets, with high possibility of triplex formation by Hmrhl at their promoter site. Further, overexpression of PDGRFβ in Hmrhl silenced cells resulted in rescue effect of cancer associated cellular phenotypes. In addition, we also found TAL-1 to be a potential regulator of Hmrhl expression in K562 cells. Thus, we hypothesize that Hmrhl lncRNA may play a significant role in the pathobiology of CML.

UNC5B-AS1 promotes the proliferation, migration and EMT of hepatocellular carcinoma cells via regulating miR-4306/KDM2A axis

Being one of the most prevalent malignancies, hepatocellular carcinoma (HCC) threatens the health of population all over the world. Numerous researches have confirmed that long noncoding RNAs (lncRNAs) play an important role in tumor progression. Nonetheless, the mechanisms of unc-5 netrin receptor B antisense RNA 1 (UNC5B-AS1) in HCC remain obscure. Thus, this study aims to investigate the regulatory role and mechanism of UNC5B-AS1 in HCC cells. In our research, UNC5B-AS1 was subjected to gene expression analysis by RT-qPCR. Biological functions of UNC5B-AS1 in HCC cells were measured by MTT, colony formation, EdU and transwell assays. The combination between UNC5B-AS1, lysine demethylase 2A (KDM2A) and miR-4306 was validated by mechanism assays. Result showed UNC5B-AS1 was upregulated in HCC tissues and cells, contributing to the development of cancer staging and survival rate of HCC patients. Moreover, UNC5B-AS1 deficiency inhibited the proliferation, migration and epithelial-mesenchymal transition (EMT) of HCC cells. Furthermore, UNC5B-AS1 could interact with miR-4306 in HCC cells. Similarly, KDM2A was proved as the target gene of miR-4306. Finally, miR-4306 downregulation or KDM2A overexpression reversed the prohibitive role of UNC5B-AS1 knockdown in HCC progression. In short, UNC5B-AS1 accelerates the proliferation, migration and EMT of HCC cells via the regulation of miR-4306/KDM2A axis.

Development of a long noncoding RNA BC032469-dependent gold nanoparticle molecular beacon for the detection of gastric cancer cells

Aim: Long noncoding RNA (lncRNA) BC032469-dependent gold nanoparticle molecular beacons (AuNP-MB) were constructed for the detection of gastric cancer cells. Materials & methods: The AuNP-MBs were prepared according to well-established procedures based on the Au-S interaction between the gold lattice and thiol functionalized oligonucleotides. More importantly, the stability and targeting ability of AuNP-MB were verified by a series of in vitro and in vivo experiments. Results: The lncRNA-dependent probes were successfully utilized for AuNP-MB-based intracellular imaging, with fluorescence effectively emitted in GC cells, but not in normal cells. Notably, such fluorescent emission was positively correlated with lncRNA BC032469 expression. Conclusion: The authors developed an effective fluorescent imaging probe for the recognition of gastric cancer cells.

miR-1207-5p suppresses laryngeal squamous cell carcinoma progression by downregulating SKA3 and inhibiting epithelial-mesenchymal transition

Laryngeal squamous cell carcinoma (LSCC) is the second most common head and neck cancer. Previously, we discovered that miR-1207-5p was downregulated in LSCC. In this study, the clinical significance, function, and mechanism of miR-1207-5p in LSCC were investigated. Downregulation of miR-1207-5p was found to be strongly linked to the malignant progression of LSCC. Functional studies revealed that miR-1207-5p upregulation suppressed LSCC cell proliferation, invasion, migration, and xenograft tumor growth. Bioinformatics analysis revealed that miR-1207-5p target genes were involved in cell cycle regulation, proliferation, adhesion, and the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Mechanistic studies revealed that miR-1207-5p interacts directly with the 3′ untranslated region of spindle and kinetochore associated complex subunit 3 (SKA3) and downregulates SKA3 expression. Furthermore, SKA3 was found to be overexpressed in LSCC, and its high expression was associated with tumor progression and a poor prognosis. Rescue experiments demonstrated that miR-1207-5p inhibited the malignant phenotypes of LSCC via SKA3. Furthermore, miR-1207-5p upregulation or knockdown of SKA3 inhibited the epithelial-mesenchymal transition (EMT). Collectively, miR-1207-5p inhibited LSCC malignant progression by downregulating SKA3 and preventing EMT. These findings provide new insights into the mechanism of LSCC progression, as well as new potential biomarkers and therapeutic targets for LSCC diagnosis and treatment.

Long Non-coding RNAs: Potential Players in Cardiotoxicity Induced by Chemotherapy Drugs

One of the most important side effects of chemotherapy is cardiovascular complications, such as cardiotoxicity. Many factors are involved in the pathogenesis of cardiotoxicity; one of the most important of which is long non-coding RNAs (lncRNAs). lncRNA has 200-1000 nucleotides. It is involved in important processes such as cell proliferation, regeneration and apoptosis; today it is used as a prognostic and diagnostic factor. A, various drugs by acting on lncRNAs can affect cells. Therefore, by accurately identifying IncRNAs function, we can play an effective role in preventing the development of cardiotoxicity-induced chemotherapy drugs, and use them as a therapeutic strategy to improve clinical symptoms and increase patient survival.

MiRNA-Wnt signaling regulatory network in colorectal cancer

Colorectal cancer (CRC) is one of the common malignancies worldwide and the Wnt signaling pathway is recognized as the main disrupted pathway in this malignancy. MicroRNAs (miRNAs) are recognized to contribute to the pathogenesis of CRC by triggering or impeding the Wnt signaling pathway. In addition, transcriptional regulation of miRNAs by canonical Wnt signaling also participates in CRC cell progression. In this review, we present comprehensive literature of the existing data on the interaction of miRNAs and Wnt signaling that could be useful in future studies in the field of CRC management.

Roles of ncRNAs as ceRNAs in Gastric Cancer

Although ignored in the past, with the recent deepening of research, significant progress has been made in the field of non-coding RNAs (ncRNAs). Accumulating evidence has revealed that microRNA (miRNA) response elements regulate RNA. Long ncRNAs, circular RNAs, pseudogenes, miRNAs, and messenger RNAs (mRNAs) form a competitive endogenous RNA (ceRNA) network that plays an essential role in cancer and cardiovascular, neurodegenerative, and autoimmune diseases. Gastric cancer (GC) is one of the most common cancers, with a high degree of malignancy. Considerable progress has been made in understanding the molecular mechanism and treatment of GC, but GC’s mortality rate is still high. Studies have shown a complex ceRNA crosstalk mechanism in GC. lncRNAs, circRNAs, and pseudogenes can interact with miRNAs to affect mRNA transcription. The study of the involvement of ceRNA in GC could improve our understanding of GC and lead to the identification of potential effective therapeutic targets. The research strategy for ceRNA is mainly to screen the different miRNAs, lncRNAs, circRNAs, pseudogenes, and mRNAs in each sample through microarray or sequencing technology, predict the ceRNA regulatory network, and, finally, conduct functional research on ceRNA. In this review, we briefly discuss the proposal and development of the ceRNA hypothesis and the biological function and principle of ceRNAs in GC, and briefly introduce the role of ncRNAs in the GC’s ceRNA network.

LncRNA HCG11/miR-579-3p/MDM2 axis modulates malignant biological properties in pancreatic carcinoma via Notch/Hes1 signaling pathway

BACKGROUND

Increasing reports have revealed that dysregulated expression of long non-coding RNAs (lncRNAs) is involved in pancreatic carcinoma progression. This study intends to explore the function and molecular mechanism of lncRNA HLA complex group 11 (HCG11) in pancreatic carcinoma.

METHODS

The expression profiles of HCG11 in pancreatic carcinoma samples were detected by qPCR. Bioinformatics analysis was applied to detect the associations among HCG11/miR-579-3p/MDM2. The malignant properties of pancreatic carcinoma cells were measured by numerous biological assays. Xenograft model was exploited to detect the effect of HCG11 on tumor growth.

RESULTS

A significant increase of HCG11 was occurred in pancreatic carcinoma samples. Knockdown of HCG11 suppressed the progression of pancreatic carcinoma cells. Bioinformatics analysis revealed that HCG11 upregulated MDM2 expression by competitively targeting miR-579-3p. The rescue assays showed that miR-579-3p reversed cell behaviors caused by HCG11, and MDM2 reversed cell properties induced by miR-579-3p. The Notch1 intracellular domain (NICD) and Hes1 protein levels were increased by overexpression of HCG11/MDM2. The tumor growth was suppressed after depletion of HCG11, followed by suppressing Ki67, PCNA and Vimentin expression, increasing TUNEL-positive cells and E-cadherin expression.

CONCLUSIONS

Our observations highlighted that HCG11 contributed to the progression of pancreatic carcinoma by promoting growth and aggressiveness, and inhibiting apoptosis via miR-579-3p/MDM2/Notch/Hes1 axis.

Exosomal LINC00355 derived from cancer-associated fibroblasts promotes bladder cancer cell proliferation and invasion by regulating miR-15a-5p/HMGA2 axis

We have previously demonstrated that exosomes derived from cancer-associated fibroblasts (CAFs) promote bladder cancer (BC) cell proliferation and invasion by transferring LINC00355. In this study, the molecular mechanisms underlying the pro-bladder cancer action of exosomal LINC00355 were explored. CAFs were obtained from BC tumor tissues, and normal fibroblasts (NFs) were obtained from adjacent normal tissues. Human BC cell lines (T24 and 5367) were incubated with NF-Exo (exosomes from NFs), CAF-Exo (exosomes from CAFs), CAFsi-Ctrl-Exo (exosomes from si-Ctrl-transfected CAFs), and CAFsi-LINC00355-Exo (exosomes from si-LINC00355-transfected CAFs). BC cell proliferation and invasion were evaluated by MTT and Transwell assays, respectively. The interaction between miR-15a-5p and LINC00355 or HMGA2 was examined by online bioinformatics analysis and luciferase activity assay. Results showed that HMGA2 is a direct target of miR-15a-5p, and LINC00355 functions as a sponge of miR-15a-5p to upregulate HMGA2 expression. The promoting effects of CAF-Exo on HMGA2 expression, cell proliferation, and cell invasion were hindered when LINC00355 expression was inhibited in BC cells. These promoting effects were also hindered when miR-15a-5p was overexpressed or HMGA2 was silenced in BC cells. In conclusion, exosomal LINC00355 derived from CAFs promotes BC cell proliferation and invasion by regulating miR-15a-5p/HMGA2 axis.

Exosomal LINC00355 derived from cancer-associated fibroblasts promotes bladder cancer cell resistance to cisplatin by regulating miR-34b-5p/ABCB1 axis

Cisplatin resistance is a major challenge for bladder cancer (BC). Evidence indicates that exosome derived from cancer-associated fibroblasts (CAF-Exo) can promote chemotherapy resistance in various human tumors by delivering bioactive molecules. We have previously demonstrated that CAF-derived exosomal LINC00355 promotes BC cell proliferation and invasion. However, the underlying mechanisms are still unclear. In this study, we aimed to investigate the role and mechanisms of CAF-derived exosomal LINC00355 in BC cell resistance to cisplatin. Exosomes were isolated from normal fibroblasts (NFs) and BC tumor-derived CAFs, namely, NF-Exo and CAF-Exo. CAFs were transfected with si-Ctrl or si-LINC00355 and then different exosomes were isolated, namely, CAFsi-Ctrl-Exo and CAFsi-LINC00355-Exo. The human BC cell lines (T24 and 5367) were incubated with NF-Exo, CAF-Exo, CAFsi-Ctrl-Exo, and CAFsi-LINC00355-Exo in the presence of cisplatin. MTT proliferation assay and flow cytometric analysis showed that CAF-Exo promoted BC cell resistance to cisplatin and upregulated ABCB1 expression in BC cells by transferring LINC00355 to BC cells. Luciferase activity assay confirmed the interaction between miR-34b-5p and LINC00355 or ABCB1. qRT-PCR and western blot analysis further showed that LINC00355 sponged miR-34b-5p to upregulate ABCB1 expression. However, the promoting effects of CAF-Exo on BC cell resistance to cisplatin were abolished by miR-34b-5p overexpression and ABCB1 silencing. In conclusion, exosomal LINC00355 derived from CAFs promotes BC cell resistance to cisplatin by regulating the miR-34b-5p/ABCB1 axis.

Long noncoding RNA SNHG9 facilitates growth of glioma stem-like cells via miR-326/SOX9 axis

BACKGROUND

Glioma stem-like cells (GSCs) are greatly responsible for the progression of glioma. Long noncoding RNAs (lncRNAs) play an important role in glioma tumor progression. This study aims to explore the role and underlying mechanism of lncRNA SNHG9 in regulating GSC cell growth.

METHODS

GSCs were obtained from glioma cells (U87 and U251) and referred to as GSC-87 and GSC-251, respectively. The interactions between miR-326 and SNHG9 or SOX9 were analyzed using luciferase reporter assay. Cell growth of GSCs was evaluated by EdU assay and sphere formation assay.

RESULTS

SNHG9 expression was significantly higher in GSC-87 and GSC-251 cells than in U87 and U251 cells. SNHG9 overexpression promoted GSC cell growth, whereas SNHG9 knockdown inhibited GSC cell growth. Mechanistically, SNHG9 acted as a competitive endogenous RNA of miR-326 to elevate the expression of SOX9, a direct target of miR-326. Moreover, transfection with miR-326 inhibitor counteracted SNHG9 knockdown-mediated inhibition of GSC cell growth.

CONCLUSIONS

SNHG9 facilitates growth of GSCs via the miR-326/SOX9 axis. This study provides a promising therapeutic target for glioma treatment.

Telomerase Regulation: A Role for Epigenetics

Simple Summary

Maintenance of telomeres is a fundamental step in human carcinogenesis and is primarily regulated by telomerase and the human telomerase reverse transcriptase gene (TERT). Improved understanding of the transcriptional control of this gene may provide potential therapeutic targets. Epigenetic modifications are a prominent mechanism to control telomerase activity and regulation of the TERT gene. TERT-targeting miRNAs have been widely studied and their function explained through pre-clinical in vivo model-based validation studies. Further, histone deacetylase inhibitors are now in pre and early clinical trials with significant clinical success. Importantly, TERT downregulation through epigenetic modifications including TERT promoter methylation, histone deacetylase inhibitors, and miRNA activity might contribute to clinical study design. This review provides an overview of the epigenetic mechanisms involved in the regulation of TERT expression and telomerase activity.

Abstract

Telomerase was first described by Greider and Blackburn in 1984, a discovery ultimately recognized by the Nobel Prize committee in 2009. The three decades following on from its discovery have been accompanied by an increased understanding of the fundamental mechanisms of telomerase activity, and its role in telomere biology. Telomerase has a clearly defined role in telomere length maintenance and an established influence on DNA replication, differentiation, survival, development, apoptosis, tumorigenesis, and a further role in therapeutic resistance in human stem and cancer cells including those of breast and cervical origin. TERT encodes the catalytic subunit and rate-limiting factor for telomerase enzyme activity. The mechanisms of activation or silencing of TERT remain open to debate across somatic, cancer, and stem cells. Promoter mutations upstream of TERT may promote dysregulated telomerase activation in tumour cells but additional factors including epigenetic, transcriptional and posttranscriptional modifications also have a role to play. Previous systematic analysis indicated methylation and mutation of the TERT promoter in 53% and 31%, respectively, of TERT expressing cancer cell lines supporting the concept of a key role for epigenetic alteration associated with TERT dysregulation and cellular transformation. Epigenetic regulators including DNA methylation, histone modification, and non-coding RNAs are now emerging as drivers in the regulation of telomeres and telomerase activity. Epigenetic regulation may be responsible for reversible silencing of TERT in several biological processes including development and differentiation, and increased TERT expression in cancers. Understanding the epigenetic mechanisms behind telomerase regulation holds important prospects for cancer treatment, diagnosis and prognosis. This review will focus on the role of epigenetics in telomerase regulation.

The regulatory effect of 6-TG on lncRNA-miRNA-mRNA ceRNA network in triple-negative breast cancer cell line

Breast cancer is one of the most prevalent and recurring cancer types that leads to deaths in women. Triple-negative breast cancer (TNBC) is difficult to treat due to the lack of therapeutic targets. Many studies have focused on identifying drugs for use as alternative treatments for breast cancer. Thioguanine (6-TG) exerts antitumor effects in cancer. Increasing evidence has demonstrated that competitive endogenous ribonucleic acids (ceRNAs) are involved in cancer processes. However, the mechanism by which 6-TG regulates lncRNA-miRNA-mRNAs has not been elucidated. We evaluated the antitumor effect of 6-TG in MDA-MB-231 cells and comprehensively analyzed the RNA-Seq data of MDA-MB-231 cells treated with 6-TG. Our results showed that most tumor pathways were blocked by 6-TG. The hub genes were FN1, FLNA, FLNB, VCL, GSN, MYH10, ACTN4, KDR and EREG, and they were all down-regulated after 6-TG treatment. The coexpression network consisted of 18 microRNAs (miRNAs), 9 long noncoding RNAs (lncRNAs) and 20 mRNAs. Hsa-mir-16-5p and Hsa-mir-335-5p targeted the greatest number of mRNAs in the network. These molecules could bind to PAX8-AS1 and eliminate the inhibition of target mRNA expression. We showed that PAX8-AS1 is the main lncRNA affected by 6-TG and that PAX8-AS1 regulates the hub genes in tumor pathways by competitively binding with miR-16-5p and miR-335-5p.

Long Non-Coding RNA PCED1B-AS1 Promotes the Progression of Clear Cell Renal Cell Carcinoma Through miR-484/ZEB1 Axis

Background

Long non-coding RNA (lncRNA) has been recognized as the new regulator and biomarker for cancers. However, in clear cell renal cell carcinoma (ccRCC), the functions of lncRNAs are not well characterized. This research aimed to probe the function of lncRNA PCED1B-AS1 in the progression of ccRCC.

Materials and Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to detect the expression levels of PCED1B-AS1, microRNA-484 (miR-484), and zinc finger E-box binding homeobox 1 (ZEB1) in 40 pairs of human ccRCC tissues and corresponding adjacent kidney tissue samples. Chi-square test was employed to evaluate the association between PCED1B-AS1 expression level and clinicopathological characteristics. The effects of PCED1B-AS1, miR-484 and ZEB1 on the cell proliferation, migration and epithelial-mesenchymal transition (EMT) process of ccRCC cells were studied by CCK-8 assay, EdU cell proliferation assay, wound healing test and Western blotting. The regulatory relationships among PCED1B-AS1, miR-484, ZEB1 were examined by luciferase reporter gene assay and RNA immunoprecipitation assay.

Results

PCED1B-AS1 was remarkably up-regulated in ccRCC tissues and cell lines. High expression of PCED1B-AS1 was associated with poor prognosis of the patients. Loss-of-function experiments showed that PCED1B-AS1 could regulate the proliferation, migration and EMT of ccRCC cells. PCED1B-AS1 sponged miR-484 to suppress its expression, and miR-484 targeted the 3ʹ-UTR of ZEB1 to repress the expression of ZEB1. MiR-484 counteracted the functions of PCED1B-AS1 in promoting the proliferation, migration and EMT of ccRCC cells, and PCED1B-AS1 promotes the expression of ZEB1 via repressing miR-484.

Conclusion

PCED1B-AS1/miR-484/ZEB1 axis is involved in regulating the progression of ccRCC.

lncRNA PVT1 promotes the migration of gastric cancer by functioning as ceRNA of miR-30a and regulating Snail

Although the incidence and mortality of gastric cancer (GC) are slowly decreasing, the overall prognosis of GC patients with distal metastasis remains dismal. Long non-coding RNA PVT1 has been verified to function as a tumor promoter in several types of cancer. However, the role of PVT1 in GC metastasis remains obscure. Herein, we found that PVT1 was highly expressed in GC tissues and high PVT1 level was associated with tumor stage, lymph node metastasis, and poor prognosis. Overexpression of PVT1 significantly elevated epithelial-to-mesenchymal transition (EMT) marker (N-cadherin, ZEB1, and ZEB2) levels and promoted GC cell EMT process and tumor metastasis in vitro and in vivo. Mechanistically, Snail was identified as a direct target of miR-30a. PVT1 could bind with miR-30a and increase the expression of Snail by acting as a competing endogenous RNA, whereas re-expression of miR-30a in GC cells rescued the EMT markers, decreased Snail level, and inhibited GC cell migration. Taken together, these findings provide a new light on PVT1 in the pathogenesis and development of GC and an important implication for future therapy of the GC.

Telomere-related Markers for Cancer

Telomeres are structurally nucleoprotein complexes at termini of linear chromosomes and essential to chromosome stability/integrity. In normal human cells, telomere length erodes progressively with each round of cell divisions, which serves as an important barrier to uncontrolled proliferation and malignant transformation. In sharp contrast, telomere maintenance is a key feature of human malignant cells and required for their infinite proliferation and maintenance of other cancer hallmarks as well. Thus, a telomere-based anti-cancer strategy has long been suggested. However, clinically efficient and specific drugs targeting cancer telomere-maintenance have still been in their infancy thus far. To achieve this goal, it is highly necessary to elucidate how exactly cancer cells maintain functional telomeres. In the last two decades, numerous studies have provided profound mechanistic insights, and the identified mechanisms include the aberrant activation of telomerase or the alternative lengthening of telomere pathway responsible for telomere elongation, dysregulation and mutation of telomere-associated factors, and other telomere homeostasis-related signaling nodes. In the present review, these various strategies employed by malignant cells to regulate their telomere length, structure and function have been summarized, and potential implications of these findings in the rational development of telomere-based cancer therapy and other clinical applications for precision oncology have been discussed.

FOXD1-AS1 regulates FOXD1 translation and promotes gastric cancer progression and chemoresistance by activating the PI3K/AKT/mTOR pathway

Gastric cancer (GC) is a common gastrointestinal cancer with a high global mortality. Recent reports have suggested that long noncoding RNA (lncRNA) are implicated in multiple aspects of GC, including pathogenesis, progression, and therapeutic response. Herein, we investigated the function of FOXD1-AS1 in GC progression and chemoresistance. Expression of FOXD1-AS1 was low in normal stomach tissues but was upregulated in GC cell lines. Silencing of FOXD1-AS1 impaired GC cell proliferation and motility in vitro, and repressed tumor growth and metastasis in vivo. Importantly, FOXD1-AS1 upregulation increased the resistance of GC cells to cisplatin. Moreover, we found that FOXD1-AS1 promoted FOXD1 protein translation through the eIF4G-eIF4E-eIF4A translational complex. We also demonstrated that FOXD1-AS1 released eIF4E from phosphorylated 4E-BP1 and thereby strengthened the interaction of eIF4E with eIF4G by activating the PI3K/AKT/mTOR pathway. Activation of the PI3K/AKT/mTOR pathway was due to the post-transcriptional upregulation of PIK3CA, in turn induced by FOXD1-AS1-mediated sequestering of microRNA (miR)-466. Furthermore, we verified that FOXD1-AS1 facilitated GC progression and cisplatin resistance in a FOXD1-dependent manner. In conclusion, FOXD1-AS1 aggravates GC progression and chemoresistance by promoting FOXD1 translation via PIK3CA/PI3K/AKT/mTOR signaling. These findings highlight a novel target for treatment of patients GC, particularly patients with cisplatin resistance.

Long noncoding RNA HNF1A-AS1 regulates proliferation and apoptosis of glioma through activation of the JNK signaling pathway via miR-363-3p/MAP2K4

Long noncoding RNAs (lncRNAs) have been proven to exert important functions in the various biological processes of human cancers. It has been reported that lncRNA HNF1 homeobox A antisense RNA 1 (HNF1A-AS1) was abnormally expressed and played a role in the initiation and development of various human cancers. In this study, we confirmed that the expression level of HNF1A-AS1 was increased in glioma tissues and cells. Knockdown of HNF1A-AS1 inhibited cell proliferation and promoted cell apoptosis in glioma. Then, we disclosed the downregulation of miR-363-3p in glioma tissues and cell lines. The interaction between HNF1A-AS1 and miR-363-3p was identified in glioma cells. Furthermore, an inverse correlation between HNF1A-AS1 and miR-363-3p was observed in glioma tissues. Afterwards, we recognized that MAP2K4 was a direct target of miR-363-3p. The expression of MAP2K4 was negatively correlated with miR-363-3p while positively related to HNF1A-AS1 in glioma tissues. We also found the regulatory effect of HNF1A-AS1 on the MAP2K4-dependent JNK signaling pathway. All findings indicated that HNF1A-AS1 induces the upregulation of MAP2K4 to activate the JNK signaling pathway to promote glioma cell growth by acting as a miR-363-3p sponge.

A newly identified lncRNA H1FX-AS1 targets DACT1 to inhibit cervical cancer via sponging miR-324-3p

Background

Cervical cancer (CC) is the 4th most common cancer-related death in gynecological cancer worldwide. It has been reported that many lncRNAs contribute to oncogenesis although the fundamental mechanisms are basically unknown. Here, we aimed to identify a novel lncRNA H1FX-AS1 and explore a ceRNA network in CC oncogenesis and progression.

Methods

The expression level and the association with the prognosis of H1FX-AS1 in CC patients were analyzed based on Cancer Genome Atlas (TCGA) datasets, and further verified in 50 CC patients. The biological role of H1FX-AS1 was investigated in vitro and in vivo by over-expression of H1FX-AS1 in CC cells; the potential binding sites between H1FX-AS1 and miRNA, between miR-324-3p and DACT1 were predicted by LncBASE and Targetscan respectively, which were further verified by dual-luciferase reporter assay, RNA pull-down and point mutation; the relationship between genes was analyzed by Pearson correlation; the rescue experiments were used to further explore the involved molecular mechanism.

Results

Lower H1FX-AS1 expression in CC tissues was found to be associated with the poor prognosis of CC patients. Over-expression of H1FX-AS1 inhibited CC cell proliferation, migration and invasion, while induced apoptosis by sponging miR-324-3p to up-regulate the DACT1 expression level.

Conclusion

A novel lncRNA H1FX-AS1 was identified, which acted as a competing endogenous RNA (ceRNA) of miR-324-3p to inhibit DACT1 mediated CC progression. Therefore, H1FX-AS1 is a new prognostic predictor and targeting the factors in the H1FX-AS1/miR-324-3p/DACT1 axis is the novel potential therapeutic strategy for CC.

Long non-coding RNA LINC01426 facilitates glioblastoma progression via sponging miR-345-3p and upregulation of VAMP8

Background

Long non-coding RNAs (lncRNAs) has been extensively reported play important roles in regulating the development and progression of cancers, including Glioblastoma (GBM). LINC01426 is a novel lncRNA that has been identified as an oncogenic gene in GBM. Herein, we attempted to elucidate the detailed functions and underlying mechanisms of LINC01426 in GBM.

Methods

LINC01426 expression in GBM cell lines and tissues were detected by quantitative real-time PCR (qRT-PCR). Cell Counting Kit-8 (CCK8) assays, colony formation assays, subcutaneous tumor formation assays were utilized to investigate the biological functions of LINC01426 in GBM. Dual-luciferase reporter assays, RNA immunoprecipitation (RIP) and bioinformatic analysis were performed to determine the underlying mechanisms.

Results

LINC01426 is up-regulated in malignant GBM tissues and cell lines and it is capable to promote GBM cell proliferation and growth. Mechanistically, LINC01426 serves as a molecular sponge to sequester the miR345-3p and thus enhancing the level of VAMP8, an oncogenic coding gene, to promote GBM progression.

Conclusions

Our results revealed the detailed mechanisms of LINC01426 facilitated cell proliferation and growth in GBM and report the clinical value of LINC01426 for GBM prognosis and treatment.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

Long non-coding RNA NBAT1 inhibits the progression of glioma through the miR-21/SOX7 axis

Glioma is one of the most prevalent types of malignancy in the central nervous system worldwide, and the prognosis of patients with late stage glioma remains poor. Thus, the development of promising therapeutic strategies against glioma is essential. Long non-coding RNAs (lncRNAs) are functional RNA molecules involved in the initiation and progression of tumors, including glioma. Investigation on the regulatory roles of lncRNAs may facilitate the development of effective treatments. lncRNA NBAT1 is associated with the growth and metastasis of cancer; however, its underlying molecular mechanisms remain unknown. Thus, the present study aimed to investigate the effects of NBAT1 in glioma. The expression levels of NBAT1, microRNA (miRNA/miR)-21 and SOX7 in patients with glioma, and healthy donors using reverse transcription-quantitative PCR analysis. Human glioma cells (A172 and AM138) and normal astrocytes were used to establish the NBAT1-knockdown and overexpression models. Cell Counting Kit-8 and Transwell assays were performed to determine whether NBAT1 exerted effects on cell proliferation, migration and invasion. The results demonstrated that NBAT1 expression decreased in glioma tissues compared to normal samples. Additionally, downregulation of NBAT1 was detected in human glioma cells compared with normal astrocytes. Overexpression of NBAT1 inhibited glioma cell proliferation, migration and invasion. In addition, miR-21 was identified as a potential target of NBAT1, and the effects of miR-21-induced cell proliferation and metastasis were reversed following overexpression of NBAT1. Furthermore, SOX7 was predicted as the potential target of miR-21, and its expression was upregulated in glioma cells by overexpression of NBAT1 compared with the vehicle only control. Taken together, the results of the present study provide novel insight into the functions of NBAT1 in glioma, suggesting that the NBAT1/miR-21/SOX7 axis may act as a potential therapeutic target for the treatment of patients with glioma.

The prognostic value of COL3A1/FBN1/COL5A2/SPARC-mir-29a-3p-H19 associated ceRNA network in Gastric Cancer through bioinformatic exploration

Increasing studies on malignant tumors have proposed a new competing endogenous RNA (ceRNA) regulatory mechanism that mRNA, miRNA and lncRNA interact with each other. However, the mRNA-miRNA-lncRNA associated ceRNA network in gastric cancer remains unknown. We used online bioinformatic softwares to predict the hub genes and their upstream miRNAs and lncRNAs in gastric cancer, and then performed survival analyses. After collecting gastric cancer tissue samples and performing PCR experiments, the correlations among predicted mRNA, miRNA and lncRNA were further verified. A total of 101 up-regulated significant differentially expressed genes (DEGs) and 219 down-regulated significant DEGs in gastric cancer were confirmed. Functional enrichment analyses of these significant DEGs indicated that they were potentially enriched in some pathways involved in tumor malignant biological processes or metabolism. Then, we identified 20 hub genes in the PPI networks. Combined with expression and survival analyses, 8 up-regulated genes and 1 down-regulated gene were identified as central genes and acted as important prognostic roles in gastric cancer. 17 miRNAs were confirmed that might potentially regulate the expressions of these central genes. But only 8 out of them indicated better outcome in gastric cancer. Further, 79 lncRNAs were predicted that might have the potence to combine with the 8 central miRNAs. The lncRNA H19 was eventually defined as a central lncRNA by survival analyses. Stimultaneously, we found that there were certain interactions among lncRNA, miRNA and mRNAs in 50 gastric cancer tissues by qRT-PCR. Moreover, the high expression of H19 is associated with advanced TNM stage, primary tumor and lymph nodes, indicating a poor prognosis. In summary, we uncovered the prognostic value of COL3A1/FBN1/COL5A2/SPARC-mir-29a-3p-H19 ceRNA network in gastric cancer.

Long non-coding RNA RP11-59H7.3 promotes cell proliferation and invasion metastasis in colorectal cancer by miR-139-5p/NOTCH1 axis

Increasing evidence suggests long non-coding RNAs (lncRNAs) are distinctively expressed in several cancers. However, the functions of these lncRNAs in cancer development remain unknown. In the current study, we report high expression of a novel lncRNA, RP11-59H7.3, and its association with prognosis in colorectal cancer (CRC) patients. Functional analyses of this lncRNA revealed its role in promoting proliferation and progression of the cell cycle, as well as enhancement of cell migration and invasion. Furthermore, our results revealed that knockdown of RP11-59H7.3 promoted cell apoptosis, with luciferase reporter assays showing that it directly binds to miR-139-5p. Knockdown of this lncRNA significantly reduced expression of NOTCH1, a direct target of miR-139-5p. Additionally, we show that suppression NOTCH1 by miR-139-5p could be partially rescued by overexpressing RP11-59H7.3. Analysis of the relationship between RP11-59H7.3 and miR-139-5p, in CRC tissues, showed a negative correlation while a positive association was observed between the RP11-59H7.3 expression and levels of NOTCH1. Taken together, these results demonstrated that the RP11-59H7.3/miR-139-5p/NOTCH1 axis functions as a key regulator in CRC metastasis. RP11-59H7.3 represents a potential biomarker for CRC diagnosis and could be an important target for development of novel therapies to manage the disease.

Construction and Analysis of a ceRNA Network Reveals Potential Prognostic Markers in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide and is derived from an accumulation of genetic and epigenetic changes. This study explored potential prognostic markers in CRC via the construction and in-depth analysis of a competing endogenous RNA (ceRNA) network, which was generated through a three-step process. First, we screened candidate hub genes in CRC as the primary gene markers to survey their related regulatory non-coding RNAs, miRNAs. Second, the interacting miRNAs were used to search for associated lncRNAs. Thus, candidate RNAs were first constructed into ceRNA networks based on close associations with miRNAs. Further analysis at the isomiR level was also performed for each miRNA locus to understand the detailed expression patterns of the multiple variants. Finally, RNAs were performed an in-depth analysis of expression correlations, which contributed to further screening and validation of potential RNAs with close correlations to each other. Using this approach, nine hub genes, 13 related miRNAs, and 29 candidate lncRNAs were collected and used to construct the ceRNA network. Further in-depth analysis identified the MFAP5-miR-200b-3p-AC005154.6 axis as a potential prognostic marker in CRC. MFAP5 and miR-200b-3p have previously been reported to play important roles in tumorigenesis. These RNAs showed potential prognostic values, and the combination of them may have more sensitivity than using them alone. In conclusion, MFAP5, miR-200b-3p, and AC005154.6 may have potential prognostic value in CRC and may provide a prognostic reference for this patient population.

Long non-coding RNA UCA1 promotes autophagy by targeting miR-96-5p in acute myeloid leukaemia

Long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been identified as an oncogene and is involved in acute myeloid leukaemia (AML). Autophagy contributes to tumourigenesis and cancer cell survival. The purpose of this study was to investigate the regulatory role and mechanism of UCA1 in AML cell viability by its effect on autophagy. The expression of UCA1, miR-96-5p, and ATG7 was determined by qRT-PCR and western blot. Cell proliferation was examined by MTT assay. The autophagy level was assessed by green fluorescent protein (GFP)-LC3 immunofluorescence and western blot. The interaction between UCA1 and miR-96-5p or ATG7 was analyzed by luciferase reporter activity. The results showed that UCA1 promoted AML cell proliferation by inducing autophagy. Mechanistically, UCA1 acted as a sponge of miR-96-5p by binding to miR-96-5p. ATG7 was a direct target of miR-96-5p and positively regulated by UCA1. Further results showed that the miR-96-5p mimic effectively counteracted the UCA1 overexpression-mediated induction of the ATG7/autophagy pathway. Collectively, UCA1 functions as a sponge of miR-96-5p to upregulate its target ATG7, thereby resulting in autophagy induction. Our findings reveal a UCA1-mediated molecular mechanism responsible for autophagy induction in AML and help to improve the understanding of the molecular mechanism of AML progression.

Long noncoding RNA RP11-626G11.3 promotes the progression of glioma through miR-375-SP1 axis

Gliomas are the most common malignant tumor in the central nervous system and are also one of the leading causes of death in cancer patients. Recently, mounting evidence suggested that both long noncoding RNAs (lncRNAs) and microRNAs play important roles in the proliferation and invasion of cancers, including gliomas. However, the role of lncRNA RP11-626G11.3 in glioma-genesis is still uncovered. Results indicated that lncRNA RP11-626G11.3 was up-regulated in glioma tissues and cell lines, moreover, its overexpression positively correlated with the poor prognosis and advanced pathological stages. Gain and loss of functional experiments demonstrated that lncRNA RP11-626G11.3 promoted the proliferation and invasion of glioma cells in vitro. The knockdown of lncRNA RP11-626G11.3 repressed the tumor growth in vivo. Mechanistically, lncRNA RP11-626G11.3 positively regulated the SP1 expression via competitively sponging with miR-375. Overall, our study shows that lncRNA RP11-626G11.3 promotes glioma progression by sponging miR-375 to regulate SP1 expression, which may provide a novel therapeutic strategy for glioma.

LncRNA OIP5-AS1 promotes cell proliferation and migration and induces angiogenesis via regulating miR-3163/VEGFA in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs) have been reported to play a significant role in the occurrence and progression of tumors. In different tumors, they can either act as an oncogene or tumor suppressor via modulating various target mRNAs. OIP5-AS1 belongs to lncRNA family. It has been reported to be involved in the tumorigenesis of some cancers, such as bladder cancer, gastric cancer, and multiple myeloma. However, the role it plays in hepatocellular carcinoma (HCC) remains unclear. This study aims to explore the inherent mechanism of lncRNA OIP5-AS1 in HCC. In the first place, qRT-PCR found that OIP5-AS1 and VEGFA expressions were significantly increased while miR-3163 was obviously reduced in HCC cells and tissues. Next, a series of functional experiments found that knockdown of OIP5-AS1 suppressed HCC cell proliferation, migration and angiogenesis abilities while promoting cell apoptosis simultaneously. Last but not least, miR-3163 inhibition or VEGFA overexpression can reverse the anti-tumor effect of OIP5-AS1. In summary, OIP5-AS1 affects HCC proliferation, metastasis, and angiogenesis in HCC by regulating VEGFA expression through sponging miR-3163.

YY1-induced upregulation of FOXP4-AS1 and FOXP4 promote the proliferation of esophageal squamous cell carcinoma cells

Esophageal squamous cell carcinoma (ESCC) belongs to one of the most common malignant tumors worldwide and possesses high mortality. Long non-coding RNAs (lncRNAs) have been demonstrated to be essential biological participants in the progression of ESCC. On the basis of bio-informatics prediction, forkhead box P4 antisense RNA 1 (FOXP4-AS1) and forkhead box P4 (FOXP4) were upregulated in esophageal carcinoma samples and were positively correlated with each other. The present study aimed to explore the function of FOXP4-AS1 and FOXP4 in ESCC cells. Function assays disclosed that knockdown of FOXP4-AS1 or FOXP4 efficiently suppressed cell proliferation and induced cell apoptosis. Moreover, FOXP4-AS1 positively regulated FOXP4 by interacting with insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) to stabilize FOXP4 messenger RNA. In addition, FOXP4-AS1 could upregulate the expression of FOXP4 by sponging miR-3184-5p. Finally, we found that Yin Yang 1 (YY1) is a transcription factor that can transcriptionally activate both FOXP4-AS1 and FOXP4 in ESCC cells. In a word, YY1-induced upregulation of FOXP4-AS1 and FOXP4 promote the proliferation of ESCC cells.

Long non-coding RNA UCA1 modulates cell proliferation and apoptosis by regulating miR-296-3p/Myc axis in acute myeloid leukemia

Acute myeloid leukemia (AML) is a common hematopoietic malignancy with a generally poor prognosis. Long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been identified as an oncogene in various malignancies including AML. However, the role and mechanisms of UCA1 in AML tumorigenesis were incompletely understood. Hence, this study aims to investigate whether UCA1 regulates AML progression by miR-296-3p/Myc axis. Cell proliferation and apoptosis were evaluated by MTT assay and flow cytometry, respectively. Luciferase reporter assay was performed to analyze the interaction between miR-296-3p and UCA1 or Myc. The results showed that UCA1 knockdown inhibited proliferation and induced apoptosis in AML cells (U937 and HL60). Mechanistically, UCA1 acted as a sponge of miR-296-3p by binding to miR-296-3p. Myc, a target of miR-296-3p, was positively regulated by UCA1. Functional assay showed that the anti-AML effect of UCA1 knockdown could be abrogated by miR-296-3p inhibition and Myc overexpression. Moreover, UCA1 knockdown inhibited AML cell tumorigenesis in vivo, which was associated with regulation of miR-296-3p and Myc expression. In conclusion, UCA1 modulates AML progression by regulating miR-296-3p/Myc axis.

Non-coding RNAs in GI cancers: from cancer hallmarks to clinical utility

One of the most unexpected discoveries in molecular oncology, in the last decades, was the identification of a new layer of protein coding gene regulation by transcripts that do not codify for proteins, the non-coding RNAs. These represent a heterogeneous category of transcripts that interact with many types of genetic elements, including regulatory DNAs, coding and other non-coding transcripts and directly to proteins. The final outcome, in the malignant context, is the regulation of any of the cancer hallmarks. Non-coding RNAs represent the most abundant type of hormones that contribute significantly to cell-to cell communication, revealing a complex interplay between tumour cells, tumour microenvironment cells and immune cells. Consequently, profiling their abundance in bodily fluids became a mainstream of biomarker identification. Therapeutic targeting of non-coding RNAs represents a new option for clinicians that is currently under development. This review will present the biology and translational value of three of the most studied categories on non-coding RNAs, the microRNAs, the long non-coding RNAs and the circular RNAs. We will also focus on some aspirational concepts that can help in the development of clinical applications related to non-coding RNAs, including using pyknons to discover new non-coding RNAs, targeting human-specific transcripts which are expressed specifically in the tumour cell and using non-coding RNAs to increase the efficiency of immunotherapy.

Hypoxia-induced lncRNA ANRIL promotes cisplatin resistance in retinoblastoma cells through regulating ABCG2 expression

Cisplatin (DDP) resistance limits its efficacy for retinoblastoma (Rb). Hypoxia-inducible factor-1α (HIF-1α) has been shown to contribute to chemotherapy resistance in tumours under hypoxic conditions. This study was designed to explore the role and mechanism of long non-coding RNA (lncRNA) antisense non-coding RNA in the INK4 locus (ANRIL) in regulating DDP resistance in Rb cells under hypoxia and to validate whether HIF-1α was involved in this process. The interaction between HIF-1α and the promoter of ANRIL was analyzed using ChIP assay. Cell proliferation and apoptosis, as well as protein levels of drug resistance-related proteins (ABCG2 and MDR1) were examined to evaluate DDP resistance in Rb cells. The interactions between miR-328 and ANRIL as well as miR-328 and ABCG2 were analyzed using dual-luciferase reporter assays. Upon hypoxia, HIF-1α directly bound to the ANRIL promoter region to transcriptionally activate ANRIL. The hypoxia-induced ANRIL promoted Rb cell resistance to DDP, as evidenced by facilitation of cell proliferation, inhibition of cell apoptosis and upregulation of ABCG2 and MDR1. Mechanistically, ANRIL promoted Rb cell resistance to DDP by acting as a sponge of miR-328 to upregulate expression of ABCG2, which was confirmed as a direct target of miR-328. Collectively, hypoxia-induced ANRIL promotes DDP resistance in Rb cells by sponging miR-328 to upregulate ABCG2 expression.

Long Noncoding RNA Lnc-TLN2-4:1 Suppresses Gastric Cancer Metastasis and Is Associated with Patient Survival

Gastric cancer (GC) is one of the most common malignancies worldwide, and the tumor metastasis leads to poor outcomes of GC patients. Long noncoding RNAs (lncRNAs) have emerged as new regulatory molecules that play a crucial role in tumor metastasis. However, the biological function and underlying mechanism of numerous lncRNAs in GC metastasis remain largely unclear. Here, we report a novel lncRNA, lnc-TLN2-4:1, whose expression is decreased in GC tissue versus matched normal tissue, and its low expression is involved in the lymph node and distant metastases of GC, as well as poor overall survival rates of GC patients. We further found that lnc-TLN2-4:1 inhibits the ability of GC cells to migrate and invade but does not influence GC cell proliferation and confirmed that lnc-TLN2-4:1 is mainly located in the cytoplasm of GC cells. We then found that lnc-TLN2-4:1 increases the mRNA and protein expression of TLN2 in GC cells and there is a positive correlation between the expression of lnc-TLN2-4:1 and TLN2 mRNA in GC tissue. Collectively, we identified a novel lncRNA, lnc-TLN2-4:1, in GC, where lnc-TLN2-4:1 represses cell migration and invasion. The low expression of lnc-TLN2-4:1 is associated with poor overall survival rates of GC patients. These suggest that lnc-TLN2-4:1 may be a tumor suppressor during GC metastasis.