Therapeutic Targeting of Long Non-Coding RNAs in Cancer

Epigenetic regulation in human cancer: the potential role of epi-drug in cancer therapy

Epigenetics is dynamic and heritable modifications to the genome that occur independently of DNA sequence. It requires interactions cohesively with various enzymes and other molecular components. Aberrant epigenetic alterations can lead to inappropriate onset of genetic expressions and promote tumorigenesis. As the epigenetic modifiers are susceptible to extrinsic factors and reversible, they are becoming promising targets in multiple cancer therapies. Recently, various epi-drugs have been developed and implicated in clinical use. The use of epi-drugs alone, or in combination with chemotherapy or immunotherapy, has shown compelling outcomes, including augmentation of anti-tumoral effects, overcoming drug resistance, and activation of host immune response.

Decreased ZNF750 promotes angiogenesis in a paracrine manner via activating DANCR/miR-4707-3p/FOXC2 axis in esophageal squamous cell carcinoma

ZNF750 is one novel significantly mutated gene identified in esophageal squamous cell carcinoma (ESCC) using next-generation sequencing. However, its clinically relevant and potential mechanisms have remained elusive. Using genomic sequencing of 612 ESCC patients, we analyzed the associations of ZNF750 mutations with clinicopathologic features and its prognostic value. We further investigated the function and underlying mechanism of ZNF750 in angiogenesis. The results showed ZNF750 mutations/deletions are significantly associated with malignant progression and poor prognosis of ESCC patients. Decreased ZNF750 in ESCC cells induces enhanced angiogenesis of human umbilical vein endothelial cells (HUVECs) and human arterial endothelial cells (HAECs), and the effect may be indirectly mediated by FOXC2. RNA-seq and ChIP shows lncRNA DANCR is a direct downstream target of ZNF750. Furtherly, knockdown ZNF750 evokes DANCR expression, which prevents miR-4707-3p to interact with FOXC2 as a microRNA sponge in a ceRNA manner, leading to enhanced FOXC2 signaling and angiogenesis. In contrast, ZNF750 expression reverses the effect. Our study reveals a novel mechanism of ZNF750, highlights a significance of ZNF750 as a metastatic and prognostic biomarker, and offers potential therapeutic targets for ESCC patients harboring ZNF750 mutations.

A long non-coding RNA LINC00461-dependent mechanism underlying breast cancer invasion and migration via the miR-144-3p/KPNA2 axis

Background

The purpose of this study was to explore the regulatory mechanism of the long non-coding RNA (lncRNA) LINC00461 underlying the breast cancer invasion and migration via the miR-144-3p/KPNA2 axis.

Methods

Bioinformatics methods were applied to screen differentially expressed mRNAs, miRNAs and lncRNAs for construction of a competing endogenous RNA (ceRNA) network. LINC00461, KPNA2 and miR-144-3p were identified, and KPNA2 was predicted to be a target of miR-144-3p and significantly correlated with breast cancer prognosis. To make the findings more convincible, we used qRT-PCR to detect the expression levels of LINC00461 and miR-144-3p in breast cancer cells, and conducted western blot to determine KPNA2 protein level. Then, RIP was performed to assess the combination between miR-144-3p and LINC00461 or KPNA2, and dual-luciferase reporter assay was used to validate the targeted relationship between miR-144-3p and KPNA2. Furthermore, Transwell was employed for the examination of cell invasion and migration in breast cancer.

Results

LINC00461 was predicted to regulate KPNA2 through sponging miR-144-3p as revealed by the ceRNA network. Besides, LINC00461 and KPNA2 were found to be remarkably highly-expressed in breast cancer cells, while miR-144-3p was poorly-expressed. Silencing LINC00461 could promote miR-144-3p expression, thus inhibiting cell invasion and migration. In addition, KPNA2 was confirmed to be a direct target of miR-144-3p. Silencing miR-144-3p or overexpressing KPNA2 could reverse the inhibitory effect of LINC00461 silencing on cell invasion and migration in breast cancer.

Conclusion

LINC00461 promoted the expression of KPNA2 by competitively binding to miR-144-3p, thereby promoting the invasion and migration of breast cancer cells.

Crosstalk of lncRNA and Cellular Metabolism and Their Regulatory Mechanism in Cancer

The imbalanced regulation of metabolic homeostasis and energy production is highly associated with inflammation, tumor growth, metastasis and cancer progression. Both glycolysis and oxidative phosphorylation maintain metabolic homeostasis and energy production in cells. Long noncoding RNAs (lncRNAs) are a class of non-protein-coding transcripts longer than 200 nucleotides. Furthermore, lncRNAs can function as either tumor suppressors or oncogenes in cancer. Dysregulated lncRNAs reportedly regulate cancer hallmarks such as tumor growth, metabolism and metastasis. Accordingly, uncovering the interaction between lncRNAs and cellular metabolism has become a necessity when attempting to identify effective therapeutic and preventive strategies in cancer progression. This review summarizes important knowledge of the actions of known lncRNAs-mediated cancer metabolism.

Epigenetic Biomarkers in Gallbladder Cancer

Gallbladder cancer (GBC) is associated with various nongenetic and genetic factors. Lack of specific and sensitive diagnostic markers has significantly impacted the mortality of this disease. Here we discuss the recent discovery of epigenetic changes that show great promise as diagnostic biomarkers as well as potential therapeutic targets for GBC.

Emerging Roles and Potential Applications of Non-Coding RNAs in Glioblastoma

Non-coding RNAs (ncRNAs) comprise a diversity of RNA species, which do not have the potential to encode proteins. Non-coding RNAs include two classes of RNAs, namely: short regulatory ncRNAs and long non-coding RNAs (lncRNAs). The short regulatory RNAs, containing up to 200 nucleotides, include small RNAs, such as microRNAs (miRNA), short interfering RNAs (siRNAs), piwi-interacting RNAs (piRNAs), and small nucleolar RNAs (snoRNAs). The lncRNAs include long antisense RNAs and long intergenic RNAs (lincRNAs). Non-coding RNAs have been implicated as master regulators of several biological processes, their expression being strictly regulated under physiological conditions. In recent years, particularly in the last decade, substantial effort has been made to investigate the function of ncRNAs in several human diseases, including cancer. Glioblastoma is the most common and aggressive type of brain cancer in adults, with deregulated expression of small and long ncRNAs having been implicated in onset, progression, invasiveness, and recurrence of this tumor. The aim of this review is to guide the reader through important aspects of miRNA and lncRNA biology, focusing on the molecular mechanism associated with the progression of this highly malignant cancer type.

Roles of lncRNAs in cancer: Focusing on angiogenesis

Approximately 98% of the human genome consists of non-coding sequences that are classified into two classes by size: small non-coding RNAs (≤200 nucleotides) and long non-coding RNAs (≥200 nucleotides). Long non-coding RNAs (lncRNAs) are involved in various cellular events and act as guides, signals, decoys, and dynamic scaffolds. Due to their oncogenic and tumor suppressive roles, lncRNAs are important in cancer development and growth. LncRNAs play their roles by modulating cancer hallmarks, including DNA damage, metastasis, immune escape, cell stemness, drug resistance, metabolic reprogramming, and angiogenesis. Angiogenesis is vital for solid tumors which guarantees their growth beyond 2 mm³. Tumor angiogenesis is a complex process and is regulated through interaction between pro-angiogenic and anti-angiogenic factors within the tumor microenvironment. There are accumulating evidence that different lncRNAs regulate tumor angiogenesis. In this paper, we described the functions and mechanisms of lncRNAs in tumor angiogenesis.

An Emerging Class of Long Non-coding RNA With Oncogenic Role Arises From the snoRNA Host Genes

The small nucleolar RNA host genes (SNHGs) are a group of long non-coding RNAs, which are reported in many studies as being overexpressed in various cancers. With very few exceptions, the SNHGs (SNHG1, SNHG3, SNHG5, SNHG6, SNHG7, SNHG12, SNHG15, SNHG16, SNHG20) are recognized as inducing increased proliferation, cell cycle progression, invasion, and metastasis of cancer cells, which makes this class of transcripts a viable biomarker for cancer development and aggressiveness. Through our literature research, we also found that silencing of SNHGs through small interfering RNAs or short hairpin RNAs is very effective in both in vitro and in vivo experiments by lowering the aggressiveness of solid cancers. The knockdown of SNHG as a new cancer therapeutic option should be investigated more in the future.

LncRNA-ATB in cancers: what do we know so far?

Cancer-related deaths did not apparently decrease in the past decades despite aggressive treatments. It's reported that cancer will become the leading cause of death worldwide in the twenty-first century. Increasing evidence has revealed that lncRNAs will emerge as promising cancer biomarkers or therapeutic targets in cancer treatment. LncRNA-ATB, a long noncoding RNA activated by TGF-β, was found to be abnormally expressed in certain cancers and participate in the development and progression of tumors. In addition, aberrant lncRNA-ATB expression was also associated with clinical characteristics of tumors. The purpose of this review is to summarize functions and underlying mechanisms of lncRNA-ATB in tumors, and discuss whether lncRNA-ATB can be a biomarker and therapeutic target in cancers.

The Epigenetic Drug Discovery Landscape for Metabolic-associated Fatty Liver Disease

Despite decades of research, effective therapies for metabolic (dysfunction)-associated fatty liver disease (MAFLD) are lacking. An increasing body of evidence suggests that epigenetic dysregulation is frequent in MAFLD, and orchestrates many aspects of its development and progression. Furthermore, the high plasticity of epigenetic modifications in response to environmental cues renders epigenetics a novel area for therapeutic drug discovery. Over recent years, several epigenetics-based drugs and diagnostic biomarkers have entered clinical development and/or obtained regulatory approval. Here, we review recent advances in our understanding of epigenetic regulation and programming during MAFLD, including DNA methylation, histone modifications, chromatin remodelling, transcriptional control, and noncoding (nc)RNAs. We also discuss the potential translational implications and challenges of epigenetics in the context of MAFLD.

The long non-coding RNA PIK3CD-AS2 promotes lung adenocarcinoma progression via YBX1-mediated suppression of p53 pathway

The underlying mechanisms of long non-coding RNAs (lncRNA) participating in the progression of lung cancers are largely unknown. We found a novel lncRNA, PIK3CD antisense RNA 2 (PIK3CD-AS2), that contributes to lung adenocarcinoma (LUAD) progression. The expression characteristics of PIK3CD-AS2 in LUAD were analyzed using microarray expression profile, The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, and validated in 92 paired LUAD tissues by chromogenic in situ hybridization. Our data confirmed that PIK3CD-AS2 expression is a crucial regulator of LUAD progression and associated with shorter patient survival. In vitro studies showed that PIK3CD-AS2 increased cell growth and slowed apoptosis in p53^wt cells but not in p53^null cells. Mechanically, it is demonstrated that PIK3CD-AS2 bound to and maintained the stability of Y-box binding protein 1 (YBX1), a potent destabilizer of p53, by impeding its ubiquitination and degradation. Downexpression of YBX1 reversed PIK3CD-AS2-mediated inhibition of p53 signaling. Additionally, the therapeutic effect evaluation of a locked nuclear acid (LNA) specifically targeting PIK3CD-AS2 showed an anti-tumor activity in mice with A549 cells xenograft and p53 wild-type LUAD patient-derived tumor xenograft (PDTX) model. Clinically, the high expression of PIK3CD-AS2 showed a poor disease-free survival in p53 wild-type patients in TCGA database. Our findings suggest that PIK3CD-AS2 regulates LUAD progression and elucidate a new PIK3CD-AS2/YBX1/p53 signaling axis, providing a potential lncRNA-directed therapeutic strategy especially in p53 wild-type LUAD patients.

Integrated proteogenomic deep sequencing and analytics accurately identify non-canonical peptides in tumor immunopeptidomes

Efforts to precisely identify tumor human leukocyte antigen (HLA) bound peptides capable of mediating T cell-based tumor rejection still face important challenges. Recent studies suggest that non-canonical tumor-specific HLA peptides derived from annotated non-coding regions could elicit anti-tumor immune responses. However, sensitive and accurate mass spectrometry (MS)-based proteogenomics approaches are required to robustly identify these non-canonical peptides. We present an MS-based analytical approach that characterizes the non-canonical tumor HLA peptide repertoire, by incorporating whole exome sequencing, bulk and single-cell transcriptomics, ribosome profiling, and two MS/MS search tools in combination. This approach results in the accurate identification of hundreds of shared and tumor-specific non-canonical HLA peptides, including an immunogenic peptide derived from an open reading frame downstream of the melanoma stem cell marker gene ABCB5. These findings hold great promise for the discovery of previously unknown tumor antigens for cancer immunotherapy.

The clinical prognostic value of lncRNA FAM83H-AS1 in cancer patients: a meta-analysis

Background

Family with sequence similarity 83 member H antisense RNA 1 (FAM83H-AS1) is a novel long non-coding RNA. Increasing studies have reported that FAM83H-AS1 is abnormally expressed in a variety of tumors and is associated with poor outcome. However, the clinical prognostic significance of lncRNA FAM83H-AS1 in tumors is not completely known.

Methods

In this meta-analysis, literature was collected up until February 5, 2020 through multifarious retrieval strategies by searching through electronic databases of PubMed, Cochrane Library, EMBASE, Medline, Web of Science, CNKI, Weipu, and Wanfang. A total of 14 studies that met the inclusion criteria with relevant clinical data and prognostic information were included in the meta-analysis.

Results

The combined results revealed that high expression of FAM83H-AS1 was associated with poor overall survival (OS) (HR = 1.63, 95% CI 1.24–2.14, P = 0.0004) in a variety of cancers. Additionally, upregulated FAM83H-AS1 expression was significantly correlated with tumor TNM stage (III/IV vs. I/II, OR = 2.40, 95% CI 1.36–4.23, P = 0.003) and lymph node metastasis (positive vs. negative, OR = 1.70, 95% CI 1.14–2.52, P = 0.008) in patients with cancer.

Conclusions

Our results of this meta-analysis indicated that elevated FAM83H-AS1 expression could predict poor prognosis in patients with cancer and suggested that FAM83H-AS1 might serve as a novel biomarker for cancer.

Recent advances in risk factors associated with ocular exfoliation syndrome

Exfoliation syndrome is generally considered a progressive age-related systemic disorder of the extracellular matrix, which is clinically characterized through the observation of flaky white aggregates on ocular tissues. Exfoliation syndrome is directly linked to exfoliative glaucoma in elderly patients, where it is known as the most common identifiable cause of open-angle glaucoma. Despite the identification of various risk factors associated with exfoliation syndrome, the exact pathogenesis of this syndrome has not been fully elucidated. There is a growing number of genome-wide association studies in different populations around the world to identify genetic factors underlying exfoliation syndrome. Besides variants in LOXL1 and CACNA1A genes, new loci have been recently identified which are believed to be associated with exfoliation syndrome. Among different genetic factors, functional variants might help to better understand mechanisms underlying this systemic disorder. Besides genetic factors, epigenetic regulation of different gene expression patterns has been thought to play a role in its pathogenesis. Other factors have been also considered to be involved in the development of exfoliation syndrome at cellular organelles level where mitochondrial impairment and autophagy dysfunction have been suggested in relation to exfoliation syndrome. This review addresses the most recent findings on genetic factors as well as cellular and molecular mechanisms involved in both the development and progression of exfoliation syndrome.

Comprehensive expression profile of long non-coding RNAs in Peripheral blood mononuclear cells from patients with neuropsychiatric systemic lupus erythematosus

Background

Long noncoding RNAs (lncRNAs) are emerging as critical regulators of gene expression in the immune system, but their impact on neuropsychiatric systemic lupus erythematosus (NPSLE) remains unknown.

Methods

RNA sequencing analysis was used to screen the comprehensive expression profile of lncRNAs and messenger RNAs (mRNAs) in peripheral blood mononuclear cells (PBMCs) from NPSLE patients, active SLE patients who had never experienced neuropsychiatric manifestations (Non-NPSLE) and healthy controls. Differentially expressed (DE) lncRNA levels were validated by qRT-PCR in 26 NPSLE patients, 31 Non-NPSLE patients and 30 healthy controls. Further, correlations of DE lncRNAs with clinical manifestations of NPSLE patients were analyzed. Finally, a bioinformatic analysis was performed to investigate the potential functions of DE genes.

Results

Four hundred and fifty-one lncRNAs and 272 mRNAs were DE between the NPSLE patients and Non-NPSLE patients, among which, significantly upregulated expression levels of NONHSAT208182.1, NONHSAT182114.1, NONHSAT106801.2, NONHSAT039491.2, ENST00000356215, NONHSAT087499.2 and NONHSAT207026.1 while downregulated expression levels of NONHSAT001281.2 and NONHSAT024353.2 were further validated in PBMCs from NPSLE patients by qRT-PCR. Bioinformatic analysis suggested several gene ontology (GO) terms and signal pathways may play important roles in NPSLE development. Co-expression networks analysis indicated that 170 lncRNAs and 46 mRNAs were included in the co-expression network. The expression level of NONHSAT039491.2 was associated with the activity of SLE and the presence of anti-dsDNA, anti-RNP antibody, dizziness and headache. NONHSAT087499.2 level correlated with anti-RNA antibody, ENST00000356215 level correlated with olfactory threshold and oral ulcer. NONHSAT208182.1 level correlated with the presence of fever, unstable walking and urinary red blood cells. NONHSAT106801.2 correlated with frequency of B cells and the presence of fever. NONHSAT024353.2 level was associated with serum IgG levels and the presence of anti-SSA and disorder of consciousness.

Conclusions

Our data provided comprehensive evidence regarding the differential expression of lncRNAs in PBMCs from NPSLE patients, indicating that these DE lncRNAs may play roles in NPSLE development. Our finding shed light on the understanding of the molecular mechanisms of lncRNAs in the pathogenesis of NPSLE.

Clinical significance of expression of MEG8 and TGM2 genes in gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the common malignant tumors, and its incidence and mortality rates are among the highest in China and even the world, posing an important threat to human health. There is still a lack of early diagnosis, treatment, and prognosis-related gene targets for GC.

AIM

To investigate the expression of maternally expressed gene 8 (MEG8) and transglutaminase-2 (TGM2) in GC and analyze their clinical significance.

METHODS

The expression of MEG8 and TGM2 in 30 pairs of GC and tumor-adjacent tissues was detected by fluorescence quantitative polymerase chain reaction. The correlation between MEG8 and TGM2 expression and clinicopathological features of GC patients was analyzed. The difference of TGM2 expression and its correlation with the survival status of GC patients were analyzed by employing the relevant research data in Oncomine database.

RESULTS

The expression of MEG8 in GC tissues was significantly lower than that in tumor-adjacent tissues (0.462 ± 0.082 vs 1.048 ± 0.149, P < 0.05), and the expression of TGM2 in GC tissues was significantly higher than that in tumor-adjacent tissues (1.202 ± 0.143 vs 0.742 ± 0.083, P < 0.05). The expression of MEG8 was correlated with age and clinical stage, and the expression of TGM2 was correlated with clinical stage (P < 0.05). The expression of TGM2 was not related to the survival status of patients with GC (P > 0.05).

CONCLUSION

MEG8 and TGM2 may be involved in the occurrence and development of GC and can be used as potential targets for the diagnosis and prognosis of GC.

Splicing dysregulation in cancer: from mechanistic understanding to a new class of therapeutic targets

RNA splicing dysregulation is widespread in cancer. Accumulating evidence demonstrates that splicing defects resulting from splicing dysregulation play critical roles in cancer pathogenesis and can serve as new biomarkers and therapeutic targets for cancer intervention. These findings have greatly deepened the mechanistic understandings of the regulation of alternative splicing in cancer cells, leading to rapidly growing interests in targeting cancer-related splicing defects as new therapies. Here we summarize the current research progress on splicing dysregulation in cancer and highlight the strategies available or under development for targeting RNA splicing defects in cancer.

Long noncoding RNA, LINC00460, as a prognostic biomarker in head and neck squamous cell carcinoma (HNSCC)

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy characterized by frequent mutations and metastasis. Long noncoding RNAs (lncRNAs) have been implicated in tumorigenesis and serve as novel prognostic biomarkers in different cancers. To enhance our understanding of lncRNAs that may have biological significance in HNSCC and may serve as prognostic biomarkers, we globally profiled lncRNAs in HNSCC by analyzing the RNA-seq data from The Atlas of Noncoding RNAs in Cancer (TANRIC) database. Of 3576 lncRNAs, we identified 926 (higher-688, lower-238) lncRNAs with a 2-fold abundance difference among the forty HNSCC and paired adjacent normal tissue. We investigated differential abundance of lncRNAs based on TP53 mutation and p16 status. We found 133 lncRNAs to have differential abundance by 2-fold among the mutant vs wild-type TP53 samples, whereas among p16-negative vs positive samples, we identified 710 lncRNAs with the same criteria. Meanwhile, analysis of the 15 most abundant lncRNAs in the tumor samples identified five lncRNAs whose higher abundance was associated with poor overall patient survival. Among these five, higher abundance of LINC00460 associated with poor patient survival in an independent cohort of 82 HNSCC patients. To further evaluate the potential function of LINC00460, we performed lncRNA-mRNAs co-expression analysis and found that higher abundance of LINC00460 associated with cancer-related biological pathways including EMT and other inflammatory response pathways. In summary, we report LINC00460 is more abundant in tumors compared to adjacent normal tissue and that it may serve as a potential prognostic biomarker in HNSCC.

Downregulated expression of lncRNA TUBA4B predicts unfavorable prognosis and suppresses glioma progression by sponging miR-183 to regulate SMAD4 expression

Introduction

Accumulating evidence has proved that long non-coding RNAs (lncRNAs) are involved in progression of glioma. Nevertheless, the role of TUBA4B in glioma remains unclear.

Material and methods

The expression of the target gene was measured by quantitative RT-PCR. The prognostic role of TUBA4B was analyzed by Meier survival analysis. Cell proliferation, colony formation, apoptosis, cell cycle, migration and invasion were detected by MTS, soft agar colony forming assay, flow cytometry, and transwell assay. The target interaction of the target gene was validated by the luciferase reporter assay, biotin pull-down assay, and RNA immunoprecipitation.

Results

We found that the expression of TUBA4B was lower in glioma tissues and cells. Moreover, patients with a low TUBA4B expression level exhibited poorer prognosis than those with high TUBA4B expression. Meanwhile, ROC analysis revealed that TUBA4B had diagnostic value to distinguish tumor patients from the healthy population. Overexpression of TUBA4B prohibited the malignancy of glioma, such as inhibition of proliferation, decrease of colony formation, arrest of the cell cycle, decline of migration and invasion, and promotion of cell apoptosis. In addition, we found that TUBA4B directly interacted with miR-183 and negatively regulated the expression of miR-183. We also observed that SMAD4 was a downriver target of miR-183 and TUBA4B subsequently exerted its tumor-suppressive effects by coordinating the expression of SMAD4 in glioma.

Conclusions

This study revealed for the first time that TUBA4B could be a tumor suppressor gene in glioma by adjustment of the TUBA4B/miR-183/SMAD4 axis, which may provide a useful prognostic biomarker and promising therapeutic target for glioma treatment.

PVT1 Long Non-coding RNA in Gastrointestinal Cancer

Whole genome and transcriptome sequencing technologies have led to the identification of many long non-coding RNAs (lncRNAs) and stimulated the research of their role in health and disease. LncRNAs participate in the regulation of critical signaling pathways including cell growth, motility, apoptosis, and differentiation; and their expression has been found dysregulated in human tumors. Thus, lncRNAs have emerged as new players in the initiation, maintenance and progression of tumorigenesis. PVT1 (plasmacytoma variant translocation 1) lncRNA is located on chromosomal 8q24.21, a large locus frequently amplified in human cancers and predictive of increased cancer risk in genome-wide association studies (GWAS). Combined, colorectal and gastric adenocarcinomas are the most frequent tumor malignancies and also the leading cause of cancer-related deaths worldwide. PVT1 expression is elevated in gastrointestinal tumors and correlates with poor patient prognosis. In this review, we discuss the mechanisms of action underlying PVT1 oncogenic role in colorectal and gastric cancer such as MYC upregulation, miRNA production, competitive endogenous RNA (ceRNA) function, protein stabilization, and epigenetic regulation. We also illustrate the potential role of PVT1 as prognostic biomarker and its relationship with resistance to current chemotherapeutic treatments.

Idiopathic Pulmonary Fibrosis: Pathogenesis and the Emerging Role of Long Non-Coding RNAs

Idiopathic pulmonary fibrosis (IPF) is a progressive chronic disease characterized by excessing scarring of the lungs leading to irreversible decline in lung function. The aetiology and pathogenesis of the disease are still unclear, although lung fibroblast and epithelial cell activation, as well as the secretion of fibrotic and inflammatory mediators, have been strongly associated with the development and progression of IPF. Significantly, long non-coding RNAs (lncRNAs) are emerging as modulators of multiple biological processes, although their function and mechanism of action in IPF is poorly understood. LncRNAs have been shown to be important regulators of several diseases and their aberrant expression has been linked to the pathophysiology of fibrosis including IPF. This review will provide an overview of this emerging role of lncRNAs in the development of IPF.

Long noncoding RNA LEF1-AS1 binds with HNRNPL to boost the proliferation, migration, and invasion in osteosarcoma by enhancing the mRNA stability of LEF1

Osteosarcoma (OS) is the most frequent type of cancer that starts in the bones, with a rather high tendency to metastasize to other bones at the early stages. Although many types of research have demonstrated that long noncoding RNAs commonly take part in the development of various cancers, the modulating mechanism of LEF1-AS1 in OS was unknown yet. In this study, our results disclosed that LEF1-AS1, as well as LEF1, had higher expression levels in OS cells than that in normal bone cells. LEF1-AS1 knockdown dramatically inhibited the proliferation, migration, as well as invasion in OS, which proved that LEF1-AS1 contributed to the growth of OS. Furthermore, HNRNPL knockdown suppressed the expression of LEF1. LEF1-AS1 was confirmed to sponge HNRNPL and HNRNPL could bind with LEF1. Both LEF1-AS1 and HNRNPL could enhance the stability of LEF1 mRNA. LEF1-AS1 acted as a promoter in stimulating the Wnt signaling pathway in OS. In rescue experiments, overexpression of LEF1 partially offset the inhibition LEF1-AS1 knockdown brought in the proliferation, migration as well as invasion of OS cells. Collectively, this study had investigated that LEF1-AS1 bound with HNRNPL to promote OS cell proliferation, migration as well as invasion by enhancing the messenger RNA stability of LEF1.

LncRNA NNT-AS1 promotes non-small cell lung cancer progression through regulating miR-22-3p/YAP1 axis

Background

Lung cancer is the leading cause of cancer‐related mortality worldwide. Studies have demonstrated that long noncoding RNA nicotinamide nucleotide transhydrogenase‐antisense RNA1 (NNT‐AS1) functioned as an oncogene in most malignancies, including non‐small cell lung cancer (NSCLC). This study aimed to investigate the underlying mechanisms of NNT‐AS1 in NSCLC progression.

Methods

The levels of NNT‐AS1, miR‐22‐3p and Yes‐associated protein (YAP1) were detected by qRT‐PCR in NSCLC tissues and cells. Kaplan‐Meier analysis was conducted to analyze the correlation between NNT‐AS1 expression and overall survival of NSCLC patients. Cell proliferation was evaluated by MTT assay. Cell migration and invasion were assessed using transwell assay. The protein levels of YAP1 and EMT‐related proteins were detected by western blot. The molecular mechanism was predicted by starBase2.0 and validated by dual‐luciferase reporter assay or RNA pull‐down assay. Xenograft analysis was carried out to analyze tumor growth in vivo.

Results

We found that the levels of NNT‐AS1 and YAP1 were enhanced, while miR‐22‐3p expression was decreased in NSCLC tissues and cells. High NNT‐AS1 expression was correlated with poor prognosis. NNT‐AS1 knockdown impeded proliferation, migration, invasion and EMT of NSCLC cells. NNT‐AS1 targeted miR‐22‐3p, and YAP1 was a target of miR‐22‐3p in NSCLC cells. Furthermore, NNT‐AS1 facilitated the progression of NSCLC by regulating miR‐22‐3p/YAP1 axis. NNT‐AS1 knockdown repressed tumor growth in vivo.

Conclusion

NNT‐AS1 facilitated proliferation, migration, invasion and EMT of NSCLC cells by sponging miR‐22‐3p and regulating YAP1 expression, which might provide a potential biomarker and therapeutic target for NSCLC.

Knockdown of LINC00473 Enhances Radiosensitivity in Hepatocellular Carcinoma via Regulating the miR-345-5p/FOXP1 Axis

Background

Hepatocellular carcinoma (HCC) is the most common form of liver cancer. Radioresistance is a significant obstacle in HCC therapy. Long non-coding RNA 473 (LINC00473) has been found to impair the effect of radiotherapy. This study aimed to explore the function and molecular basis of LINC00473 in the radiosensitivity of HCC cells.

Methods

The levels of LINC00473, miR-345-5p and Forkhead Box P1 (FOXP1) were determined by quantitative real-time polymerase chain reaction. Cell viability was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Survival fraction was calculated by colony survival assay after exposure to different doses of radiation. Cell apoptosis was evaluated by flow cytometry. The interaction among LINC00473, miR-345-5p and FOXP1 was confirmed by dual-luciferase reporter assay. The protein level of FOXP1 was detected by Western blot assay.

Results

LINC00473 and FOXP1 were up-regulated, while miR-345-5p was down-regulated in HCC tissues and cells. Radiation elevated LINC00473 expression in a dose- and time-dependent manner. Depletion of LINC00473 inhibited proliferation and heightened radiosensitivity and apoptosis in HCC cells. In addition, LINC00473 was a sponge of miR-345-5p. Also, miR-345-5p overexpression sensitized HCC cells to radiation. Moreover, miR-345-5p directly targeted FOXP1. MiR-345-5p inhibition or FOXP1 up-regulation reversed the enhanced radiosensitivity caused by LINC00473 knockdown.

Conclusion

LINC00473 contributed to radioresistance in HCC via modulating the miR-345-5p/FOXP1 axis, which might provide a promising diagnostic marker for HCC radiotherapy.

LncRNA KCNQ1OT1 regulates microRNA-9-LMX1A expression and inhibits gastric cancer cell progression

LMX1A (LIM homeobox transcription factor 1α) is a tumor suppressor protein. Our previous study has shown that microRNA-9 (“miR-9”), being upregulated in human gastric cancer (GC), targets LMX1A to promote GC cell progression. Through searching long non-coding RNA (LncRNA) database, we identified that LncRNA KCNQ1OT1 is the competing endogenous RNA (ceRNA) of miR-9. KCNQ1OT1 putatively targets miR-9. Its level is downregulated in human GC tissues. In AGS cells and primary human GC cells, forced overexpression of KCNQ1OT1, by a lentiviral construct, induced miR-9 downregulation and LMX1A upregulation. Furthermore, KCNQ1OT1 overexpression inhibited GC cell survival, proliferation, migration and invasion, but inducing apoptosis activation. Contrarily, KCNQ1OT1 silencing, by targeted siRNAs, induced miR-9 accumulation and LMX1A downregulation. Consequently, GC cell proliferation, migration and invasion were enhanced. Importantly, KCNQ1OT1 overexpression or silencing was ineffective in LMX1A knockout AGC cells. Taken together, KCNQ1OT1 inhibits GC cell progression via regulating miR-9 and LMX1A expression.

Long Non-Coding RNAs as Key Modulators of Pancreatic β-Cell Mass and Function

Numerous studies have sought to decipher the genetic and other mechanisms contributing to β-cell loss and dysfunction in diabetes mellitus. However, we have yet to fully understand the etiology of the disease or to develop satisfactory treatments. Since the majority of diabetes susceptibility loci are mapped to non-coding regions within the genome, understanding the functions of non-coding RNAs in β-cell biology might provide crucial insights into the pathogenesis of type 1 (T1D) and type 2 (T2D) diabetes. During the past decade, numerous studies have indicated that long non-coding RNAs play important roles in the maintenance of β-cell mass and function. Indeed, lncRNAs have been shown to be involved in controlling β-cell proliferation during development and/or β-cell compensation in response to hyperglycaemia. LncRNAs such as TUG-1 and MEG3 play a role in both β-cell apoptosis and function, while others sensitize β-cells to apoptosis in response to stress signals. In addition, several long non-coding RNAs have been shown to regulate the expression of β-cell-enriched transcription factors in cis or in trans. In this review, we provide an overview of the roles of lncRNAs in maintaining β-function and mass, and discuss their relevance in the development of diabetes.

Long Non-coding RNA LINC-PINT Suppresses Cell Proliferation and Migration of Melanoma via Recruiting EZH2

Long non-coding RNAs (lncRNAs) have been identified as crucial regulators in many human cancers. Many lncRNAs show aberrant expression in cancer, and some of them play critical roles in tumor proliferation, invasion, and metastasis. However, the regulatory functions of lncRNAs in melanoma progression remain to be elucidated. We utilized the Real-time PCR methodology to determine the expression of LINC-PINT in melanoma cell lines. To evaluate the effect of LINC-PINT on tumorigenesis of melanoma, we used Cell Counting Kit-8 (CCK8) and colony formation assay. Flow cytometry assay was used to detect the function of LINC-PINT on cell cycle status. PINT-interacting proteins were identified by chromatin isolation using RNA purification (ChIRP). Microarray assay and bioinformatics analysis were used to find the potential target genes of LINC-PINT and the status of LINC-PINT target gene candidate was verified using chromatin immunoprecipitation assay (ChIP). LINC-PINT plays a role in suppressing the tumorigenicity of melanoma, which was further determined by xenograft model assay. LINC-PINT was significantly downregulated in melanoma tissues and cell lines. The overexpression of LINC-PINT in tumor cells resulted in significant tumor growth reduction and migration inhibition in A375, Mum2B and CRMM1 cells. Results based on the in vivo xenograft model were further consistent with the in vitro findings that LINC-PINT impeded growth and metastasis of melanoma cells. Microarray assay and bioinformatics analysis indicated that CDK1, CCNA2, AURKA, and PCNA were potential targets of LINC-PINT. In conclusion, LINC-PINT inhibits the tumorigenicity of melanoma through recruiting EZH2 to the promoter of its target genes, leading to H3K27 trimethylation and epigenetic silencing of target genes. LINC-PINT may serve as a novel diagnostic and therapeutic target for melanoma.

Long Non-Coding RNA in Drug Resistance of Non-Small Cell Lung Cancer: A Mini Review

Lung cancer is one of main causes of cancer mortality and 83% of lung cancer cases are classified as non-small cell lung cancer (NSCLC). Patients with NSCLC usually have a poor prognosis and one of the leading causes is drug resistance. With the progress of drug therapy, the emergence and development of drug resistance affected the prognosis of patients severely. Accumulating evidence reveals that long non-coding RNAs (lncRNAs), as “dark matters” of the human genome, is of great significance to drug resistance in NSCLC. Herein, we review the role of lncRNAs in drug resistance in NSCLC.

Novel Breast-Specific Long Non-coding RNA LINC00993 Acts as a Tumor Suppressor in Triple-Negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) was characterized by breast cancers that do not express estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor (HER)-2 genes. TNBC patients are associated with a shorter median time to relapse and death for the lack of available treatment targets. Long non-coding RNAs (LncRNAs) have been reported to play an important role in the development of TNBC. We identified a novel breast-specific long non-coding RNA LINC00993, but less was known about its expression pattern and functional role in TNBC.

Methods: LINC00993 RNA expression was detected across different types of clinical breast cancer samples by using qRT-PCR. Bioinformatic methods “guilt by association” and gene set enrichment analysis (GSEA) were used to predict LINC00993 functions. Subcellular localization of LINC00993 in cells was detected by RNA fluorescence in situ hybridization (FISH). Effect of LINC00993 on cell growth was measured by plate colony formation assays, typical growth curve, and an in vivo tumor model. Cell cycle analysis was done by flow cytometry analysis. Key cell cycle regulators were detected by Western blot.

Results: LINC00993 was largely downregulated in TNBC, and higher expression indicated better outcome. LINC00993 located mainly in the nucleus. LINC00993 suppressed TNBC growth both in vitro and in vivo. LINC00993 was predicted to be involved in cell cycle pathways by using “guilt by association” and GSEA methods. Key cell cycle regulators like p16^INK4A, p14^ARF, p53, and p21 were affected by LINC00993 overexpression.

Conclusions: A new breast-specific lincRNA LINC00993 was identified with a tumor-suppressive feature and with prognostic value. This is the first research on LINC00993 function. Our results suggest that controlling LINC00993 level may be beneficial for breast cancer treatment.

LINC00682 inhibits gastric cancer cell progression via targeting microRNA-9-LMX1A signaling axis

microRNA-9 (“miR-9”), upregulated in human gastric cancer (GC) tissues, targets LMX1A (LIM homeobox transcription factor 1α) to promote GC cell progression. The underlying mechanism of miR-9 upregulation in GC is still unknown. Through searching multiple long non-coding RNA (LncRNA) databases, we here discovered that the long non-coding RNALINC00682 (long intergenic non-protein coding RNA 682) putatively targets miR-9. We show that ectopic overexpression of LINC00682 induced miR-9 downregulation but LMX1A upregulation, inhibiting AGS cell survival, proliferation, migration and invasion. Significant apoptosis activation was detected in LINC00682-overexpressed AGS cells. Contrarily, LINC00682 knockdown induced miR-9 upregulation but LMX1A downregulation, promoting AGS cell survival, proliferation, migration and invasion. In the primary human GC cells, forced LINC00682 overexpression similarly induced miR-9 downregulation and LMX1A upregulation, causing proliferation inhibition and apoptosis activation. Significantly, restoring miR-9 expression by a lentiviral construct reversed LINC00682-induced actions in GC cells. Furthermore, LINC00682 was ineffective in LMX1A KO AGS cells. Importantly, LINC00682 expression levels are significantly downregulated in human GC tissues. We conclude that LINC00682 inhibits GC cell progression via targeting miR-9-LMX1A signaling axis.

Microarray expression profiles and bioinformatics analysis of mRNAs, lncRNAs, and circRNAs in the secondary temozolomide-resistant glioblastoma

Temozolomide is a first line anti-tumor drug used for the treatment of patients with Glioblastoma multiforme (GBM). However, the drug resistance to temozolomide limits its clinical application. Therefore, novel strategies to overcome chemoresistance are desperately needed for improved treatment of human GBM. Here, we simultaneously detected, for the first time, the expression profiles of mRNAs, lncRNAs, and circRNAs in three pairs of secondary temozolomide-resistant glioblastoma (STRG) and matched primary glioblastoma tissues by microarrays. Using these data, we discovered a total of 92 mRNA, 299 lncRNAs and 53 circRNAs were altered in human glioma tissue after chemotherapy with temozolomide. The functions of differentially expressed lncRNAs, circRNAs were annotated by analysis of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). The results showed that the highest enriched GO terms of the upregulated lncRNAs were embryonic forelimb morphogenesis (BP), extracellular space (CC), and serine-type endopeptidase activity (MF). Meanwhile, GO:0035360(BP), PRC1 complex (CC), and ubiquitin-protein transferase activity (MF) were the highest enriched GO terms targeted by downregulated lncRNAs. The NF-kappa B signaling pathway were significantly enriched in the STRG. However, circRNAs highest enriched GO term was viral process, chromosome, and protein transporter activity, respectively. KEGG pathway analysis showed that circRNAs in the network were enriched in ErbB signaling pathway. Furthermore, we also predicted the potential role of these differentially expressed ncRNAs and constructed a network of lncRNAs-mRNAs and circRNAs-miRNAs to show their interactions. After a series of bioinformatics analyses, we found that low expression of NONHSAT163779 and high expression of circ_0043949 are closely related to the chemoresistance of STRG. Our findings revealed the alteration of expression patterns of mRNAs, lncRNAs, and circRNAs in the secondary temozolomide-resistant glioblastoma for the first time. NONHSAT163779 and hsa_circ_0043949 might be potential therapeutic targets and prognostic biomarkers for the treatment of glioblastoma.

A New Era of Prostate Cancer Precision Medicine

Prostate cancer is the second most common male cancer affecting Western society. Despite substantial advances in the exploration of prostate cancer biomarkers and treatment strategies, men are over diagnosed with inert prostate cancer, while there is also a substantial mortality from the invasive disease. Precision medicine is the management of treatment profiles across different cancers predicting therapies for individual cancer patients. With strategies including individual genomic profiling and targeting specific cancer pathways, precision medicine for prostate cancer has the potential to impose changes in clinical practices. Some of the recent advances in prostate cancer precision medicine comprise targeting gene fusions, genome editing tools, non-coding RNA biomarkers, and the promise of liquid tumor profiling. In this review, we will discuss these recent scientific advances to scale up these approaches and endeavors to overcome clinical barriers for prostate cancer precision medicine.

Long Non-coding RNA DANCR as an Emerging Therapeutic Target in Human Cancers

Long noncoding RNAs (lncRNAs) are emerging as important regulators of numerous biological processes, especially in cancer development. Aberrantly expressed and specifically located in tumor cells, they exert distinct functions in different cancers via regulating multiple downstream targets such as chromatins, RNAs, and proteins. Differentiation antagonizing non-protein coding RNA (DANCR) is a cytoplasmic lncRNA that generally works as a tumor promoter. Mechanically, DANCR promotes the functions of vital components in the oncogene network by sponging their corresponding microRNAs or by interacting with various regulating proteins. DANCR's distinct expression in tumor cells and collective involvement in pro-tumor pathways make it a promising therapeutic target for broad cancer treatment. Herein, we summarize the functions and molecular mechanism of DANCR in human cancers. Furthermore, we introduce the use of CRISPR/Cas9, antisense oligonucleotides and small interfering RNAs as well as viral, lipid, or exosomal vectors for onco-lncRNA targeted treatment. Conclusively, DANCR is a considerable promoter of cancers with a bright prospect in targeted therapy.

Long Non-coding RNA PVT1 as a Prognostic and Therapeutic Target in Pediatric Cancer

In recent decades, biomedical research has focused on understanding the functionality of the human translated genome, which represents a minor part of all genetic information transcribed from the human genome. However, researchers have become aware of the importance of non-coding RNA species that constitute the vast majority of the transcriptome. In addition to their crucial role in tissue development and homeostasis, mounting evidence shows non-coding RNA to be deregulated and functionally contributing to the development and progression of different types of human disease including cancer both in adults and children. Small non-coding RNAs (i.e., microRNA) are in the vanguard of clinical research which revealed that RNA could be used as disease biomarkers or new therapeutic targets. Furthermore, many more expectations have been raised for long non-coding RNAs, by far the largest fraction of non-coding transcripts, and still fewer findings have been translated into clinical applications. In this review, we center on PVT1, a large and complex long non-coding RNA that usually confers oncogenic properties on different tumor types. We focus on the compilation of early advances in the field of pediatric tumors which often lags behind clinical improvements in adult tumors, and provide a rationale to continue studying PVT1 as a possible functional contributor to pediatric malignancies and as a potential prognostic marker or therapeutic target.

LINC00673 is activated by YY1 and promotes the proliferation of breast cancer cells via the miR-515-5p/MARK4/Hippo signaling pathway

Background

An increasing number of studies have shown that long noncoding RNAs (lncRNAs) play essential roles in tumor initiation and progression. LncRNAs act as tumor promoters or suppressors by targeting specific genes via epigenetic modifications and competing endogenous RNA (ceRNA) mechanisms. In this study, we explored the function and detailed mechanisms of long intergenic nonprotein coding RNA 673 (LINC00673) in breast cancer progression.

Methods

Quantitative real-time PCR (qRT-PCR) was used to examine the expression of LINC00673 in breast cancer tissues and in adjacent normal tissues. Gain-of-function and loss-of function experiments were conducted to investigate the biological functions of LINC00673 in vitro and in vivo. We also explored the potential role of LINC00673 as a therapeutic target using antisense oligonucleotide (ASO) in vivo. RNA sequencing (RNA-seq), dual-luciferase reporter assays, chromatin immunoprecipitation (ChIP) assay, and rescue experiments were performed to uncover the detailed mechanism of LINC00673 in promoting breast cancer progression.

Results

In the present study, LINC00673 displayed a trend of remarkably increased expression in breast cancer tissues and was associated with poor prognosis in breast cancer patients. Importantly, LINC00673 depletion inhibited breast cancer cell proliferation by inhibiting the cell cycle and increasing apoptosis. Furthermore, ASO therapy targeting LINC00673 substantially suppressed breast cancer cell proliferation in vivo. Mechanistically, LINC00673 was found to act as a ceRNA by sponging miR-515-5p to regulate MARK4 expression, thus inhibiting the Hippo signaling pathway. Finally, ChIP assay showed that the transcription factor Yin Yang 1 (YY1) could bind to the LINC00673 promoter and increase its transcription in cis.

Conclusions

YY1-activated LINC00673 may exert an oncogenic function by acting as a sponge for miR-515-5p to upregulate the MARK4 and then inhibit Hippo signaling pathway, and may serve as a potential therapeutic target.

Systematic analysis identifies three-lncRNA signature as a potentially prognostic biomarker for lung squamous cell carcinoma using bioinformatics strategy

Background

Lung squamous cell carcinoma (LUSC) is the second most common histological subtype of lung cancer (LC), and the prognoses of most LUSC patients are so far still very poor. The present study aimed at integrating lncRNA, miRNA and mRNA expression data to identify lncRNA signature in competitive endogenous RNA (ceRNA) network as a potentially prognostic biomarker for LUSC patients.

Methods

Gene expression data and clinical characteristics of LUSC patients were retrieved from The Cancer Genome Atlas (TCGA) database, and were integratedly analyzed using bioinformatics methods including Differentially Expressed Gene Analysis (DEGA), Weighted Gene Co-expression Network Analysis (WGCNA), Protein and Protein Interaction (PPI) network analysis and ceRNA network construction. Subsequently, univariate and multivariate Cox regression analyses of differentially expressed lncRNAs (DElncRNAs) in ceRNA network were performed to predict the overall survival (OS) in LUSC patients. Receiver operating characteristic (ROC) analysis was used to evaluate the performance of multivariate Cox regression model. Gene expression profiling interactive analysis (GEPIA) was used to validate key genes.

Results

WGCNA showed that turquoise module including 1,694 DElncRNAs, 2,654 DEmRNAs as well as 113 DEmiRNAs was identified as the most significant modules (cor=0.99, P<1e-200), and differentially expressed RNAs in the module were used to subsequently analyze. PPI network analysis identified FPR2, GNG11 and ADCY4 as critical genes in LUSC, and survival analysis revealed that low mRNA expression of FPR2 and GNG11 resulted in a higher OS rate of LUSC patients. A lncRNA-miRNA-mRNA ceRNA network including 121 DElncRNAs, 18 DEmiRNAs and 3 DEmRNAs was established, and univariate and multivariate Cox regression analysis of those 121 DElncRNAs showed a group of 3 DElncRNAs (TTTY16, POU6F2-AS2 and CACNA2D3-AS1) had significantly prognostic value in OS of LUSC patients. ROC analysis showed that the area under the curve (AUC) of the 3-lncRNA signature associated with 3-year survival was 0.629.

Conclusions

The current study provides novel insights into the lncRNA-related regulatory mechanisms underlying LUSC, and identifying 3-lncRNA signature may serve as a potentially prognostic biomarker in predicting the OS of LUSC patients.

LncRNA RHPN1-AS1 Targeting miR-625/REG3A Promotes Cell Proliferation And Invasion Of Glioma Cells

Introduction

Glioma arises from the proliferation of neuroglial cells differentiated from the ectoderm. Evidence has confirmed that differentially expressed long non-coding RNAs (lncRNAs) may be involved in the development and progression of various tumors. The present study aimed to explore the biological function of lncRNA RHPN1-AS1 in glioma.

Materials and methods

The expressions of RHPN1-AS1 in glioma tissues and cells were examined using RT-PCR. Colony formation assay, MTT assay, wound healing assay and transwell assay were performed to detect cell cloning efficiency, proliferation, migration and invasion of glioma cells, respectively. Western blot was applied to assess the expression levels of migration-related and invasion-related proteins. Online bioinformatic tools and luciferase reporter assay were, respectively, employed to predict and verify the downstream target microRNA/gene of RHPN1-AS1.

Results

RHPN1-AS1 was up-regulated in glioma tissues and cells. The cell proliferation, migration and invasion of glioma were inhibited when the expression of RHPN1-AS1 was down-regulated in glioma cells. The expressions of migration-related and invasion-related proteins were also suppressed in siRHPN1-AS1 groups. Furthermore, we predicted and verified that RHPN1-AS1 was directly targeted to miR-625-5p/REG3A. Our study demonstrated that the knockdown of RHPN1-AS1 inhibited the proliferation, migration and invasion activity of glioma cells via regulating miR-625-5p/REG3A expression.

Conclusion

The results revealed that the lncRNA RHPN1-AS1 may be a molecular target in glioma therapy.

Noncoding RNAs: new insights into the odontogenic differentiation of dental tissue-derived mesenchymal stem cells

Odontoblasts are cells that contribute to the formation of the dental pulp complex. The differentiation of dental tissue-derived mesenchymal stem cells into odontoblasts comprises many factors and signaling pathways. Noncoding RNAs (ncRNAs), comprising a substantial part of poly-A tail mature RNAs, are considered “transcriptional noise.” Emerging evidence has shown that ncRNAs have key functions in the differentiation of mesenchymal stem cells. In this review, we discussed two major types of ncRNAs, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), in terms of their role in the odontogenic differentiation of dental tissue-derived stem cells. Recent findings have demonstrated important functions for miRNAs and lncRNAs in odontogenic differentiation. It is expected that ncRNAs will become promising therapeutic targets for dentin regeneration based on stem cells.

lncRNA miat functions as a ceRNA to upregulate sirt1 by sponging miR-22-3p in HCC cellular senescence

Hepatocellular carcinoma (HCC) is a leading cause of cancer related deaths and lacks effective therapies. Cellular senescence acts as a barrier against cancer progression and plays an important role in tumor suppression. Senescence associated long noncoding RNAs (SAL-RNAs) are thought to be critical regulators of cancer development. Here, the long noncoding RNA (lncRNA) myocardial infarction-associated transcript (miat) was first identified as an HCC specific SALncRNA. Knockdown of miat significantly promoted cellular senescence and inhibited HCC progression. Mechanistic study revealed that SAL-miat acted as a competitive endogenous RNA (ceRNA) that upregulated the expression of sirt1 by sponging miR-22-3p. Moreover, miat downregulation activated the tumor suppressor pathway (p53/p21 and p16/pRb) and stimulated senescent cancer cells to secrete senescence-associated secretory phenotype (SASP), which contributed to inhibition of tumor cell proliferation, and resulted in the suppression of HCC tumorigenesis. Together, our study provided mechanistic insights into a critical role of miat as a miRNA sponge in HCC cellular senescence, which might offer a potential therapeutic strategy for HCC treatment.

Genetic Variants of lncRNA MALAT1 Exert Diverse Impacts on the Risk and Clinicopathologic Characteristics of Patients with Hepatocellular Carcinoma

The long noncoding (lnc)RNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), plays a crucial role in the development of hepatocellular carcinoma (HCC). However, potential genetic variants (single nucleotide polymorphisms, SNPs) in MALAT1 that affect the susceptibility and progression of HCC have rarely been explored. Three tagging SNPs, viz., rs3200401 C > T, rs619586 A > G, and rs1194338 C > A, in MALAT1 were genotyped by a TaqMan allelic discrimination assay in 394 HCC patients and 1199 healthy controls. A stratified analysis showed that younger patients (<55 years) with the MALAT1 rs619586 G allele had a decreased risk of HCC under a codominant model (AOR = 0.289, 95% CI: 0.108–0.773, p = 0.013) and dominant model (AOR = 0.286, 95% CI: 0.107–0.765, p = 0.013). Female patients and patients with a smoking habit who carried the CA + AA genotype of rs1194338 had a lower risk of developing vascular invasion (p = 0.049) and a high Child–Pugh grade (B or C) (p = 0.036), respectively. Under the dominant model, smokers with the MALAT1 rs3200401 CT + TT genotype had a higher frequency of hepatitis B virus (HBV) infection (p = 0.034). Moreover, the aspartate aminotransferase was higher in patients with the rs3200401 CT + TT genotype. Furthermore, analyses of clinical datasets revealed that MALAT1 expression level was gradually unregulated during HCC development from normal liver, cirrhotic liver, dysplastic liver to HCC and correlated with poor survival rates in HCC patients, especially in the hepatitis virus-infected population.

The therapeutic and diagnostic potential of regulatory noncoding RNAs in medulloblastoma

Medulloblastoma, a central nervous system tumor that predominantly affects children, always requires aggressive therapy. Nevertheless, it frequently recurs as resistant disease and is associated with high morbidity and mortality. While recent efforts to subclassify medulloblastoma based on molecular features have advanced our basic understanding of medulloblastoma pathogenesis, optimal targets to increase therapeutic efficacy and reduce side effects remain largely undefined. Noncoding RNAs (ncRNAs) with known regulatory roles, particularly long noncoding RNAs (lncRNAs) and microRNAs (miRNAs), are now known to participate in medulloblastoma biology, although their functional significance remains obscure in many cases. Here we review the literature on regulatory ncRNAs in medulloblastoma. In providing a comprehensive overview of ncRNA studies, we highlight how different lncRNAs and miRNAs have oncogenic or tumor suppressive roles in medulloblastoma. These ncRNAs possess subgroup specificity that can be exploited to personalize therapy by acting as theranostic targets. Several of the already identified ncRNAs appear specific to medulloblastoma stem cells, the most difficult-to-treat component of the tumor that drives metastasis and acquired resistance, thereby providing opportunities for therapy in relapsing, disseminating, and therapy-resistant disease. Delivering ncRNAs to tumors remains challenging, but this limitation is gradually being overcome through the use of advanced technologies such as nanotechnology and rational biomaterial design.

Identifying targets for preventing epilepsy using systems biology of the human brain

Approximately one third of all epilepsy patients are resistant to current therapeutic treatments. Some patients with focal forms of epilepsy benefit from invasive surgical approaches that can lead to large surgical resections of human epileptic neocortex. We have developed a systems biology approach to take full advantage of these resections and the brain tissues they generate as a means to understand underlying mechanisms of neocortical epilepsy and to identify novel biomarkers and therapeutic targets. In this review, we will describe our unique approach that has led to the development of a 'NeuroRepository' of electrically-mapped epileptic tissues and associated data. This 'Big Data' approach links quantitative measures of ictal and interictal activities corresponding to a specific intracranial electrode to clinical, imaging, histological, genomic, proteomic, and metabolomic measures. This highly characterized data and tissue bank has given us an extraordinary opportunity to explore the underlying electrical, cellular, and molecular mechanisms of the human epileptic brain. We describe specific examples of how an experimental design that compares multiple cortical regions with different electrical activities has led to discoveries of layer-specific pathways and how these can be 'reverse translated' from animal models back to humans in the form of new biomarkers and therapeutic targets. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

The Eleanor ncRNAs activate the topological domain of the ESR1 locus to balance against apoptosis

MCF7 cells acquire estrogen-independent proliferation after long-term estrogen deprivation (LTED), which recapitulates endocrine therapy resistance. LTED cells can become primed for apoptosis, but the underlying mechanism is largely unknown. We previously reported that Eleanor non-coding RNAs (ncRNAs) upregulate the ESR1 gene in LTED cells. Here, we show that Eleanors delineate the topologically associating domain (TAD) of the ESR1 locus in the active nuclear compartment of LTED cells. The TAD interacts with another transcriptionally active TAD, which is 42.9 Mb away from ESR1 and contains a gene encoding the apoptotic transcription factor FOXO3. Inhibition of a promoter-associated Eleanor suppresses all genes inside the Eleanor TAD and the long-range interaction between the two TADs, but keeps FOXO3 active to facilitate apoptosis in LTED cells. These data indicate a role of ncRNAs in chromatin domain regulation, which may underlie the apoptosis-prone nature of therapy-resistant breast cancer cells and could be good therapeutic targets.

Long term estrogen deprivation can result in apoptosis in breast cancer cells. Here, the authors show that this apoptosis is induced by the long-range chromatin interaction of loci containing the ESR1 and FOXO3 genes, resulting in FOXO3-mediated apoptosis.

Integrated analysis of lncRNA-miRNA-mRNA ceRNA network in squamous cell carcinoma of tongue

Background

Numerous studies have highlighted that long non-coding RNAs (lncRNAs) can bind to microRNA (miRNA) sites as competing endogenous RNAs (ceRNAs), thereby affecting and regulating the expression of mRNAs and target genes. These lncRNA-associated ceRNAs have been theorized to play a significant role in cancer initiation and progression. However, the roles and functions of the lncRNA-miRNA-mRNA ceRNA network in squamous cell carcinoma of the tongue (SCCT) are still unclear.

Methods

The miRNA, mRNA and lncRNA expression profiles from 138 patients with SCCT were downloaded from The Cancer Genome Atlas database. We identified the differential expression of miRNAs, mRNAs, and lncRNAs using the limma package of R software. We used the clusterProfiler package for GO and KEGG pathway annotations. The survival package was used to estimate survival analysis according to the Kaplan-Meier curve. Finally, the GDCRNATools package was used to construct the lncRNA-miRNA-mRNA ceRNA network.

Results

In total, 1943 SCCT-specific mRNAs, 107 lncRNAs and 100 miRNAs were explored. Ten mRNAs (CSRP2, CKS2, ADGRG6, MB21D1, GMNN, RIPOR3, RAD51, PCLAF, ORC1, NAGS), 9 lncRNAs (LINC02560, HOXC13 − AS, FOXD2 − AS1, AC105277.1, AC099850.3, STARD4 − AS1, SLC16A1 − AS1, MIR503HG, MIR100HG) and 8 miRNAs (miR − 654, miR − 503, miR − 450a, miR − 379, miR − 369, miR − 190a, miR − 101, and let−7c) were found to be significantly associated with overall survival (log-rank p < 0.05). Based on the analysis of the lncRNA-miRNA-mRNA ceRNA network, one differentially expressed (DE) lncRNA, five DEmiRNAs, and three DEmRNAs were demonstrated to be related to the pathogenesis of SCCT.

Conclusions

In this study, we described the gene regulation by the lncRNA-miRNA-mRNA ceRNA network in the progression of SCCT. We propose a new lncRNA-associated ceRNA that could help in the diagnosis and treatment of SCCT.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5983-8) contains supplementary material, which is available to authorized users.

Macrophage-associated lncRNA ELMO1-AS1: a novel therapeutic target and prognostic biomarker for hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor. Long non-coding RNAs (lncRNAs) have been demonstrated to be abnormally expressed in many tumors and act as crucial regulators in various biological processes. However, the expression and function of the recently identified macrophage-associated lncRNA ELMO1 antisense RNA 1 (ELMO1-AS1) in HCC are unclear.

Methods

The expression of ELMO1-AS1 was determined in HCC tissues and adjacent nontumorous tissues by quantitative real-time polymerase chain reaction (qRT-PCR). The Kaplan-Meier survival analysis and Cox regression analysis were performed to establish the correlation between the expression level and survival of HCC patients in a training set and a validation set, respectively. The overexpression experiments were also conducted to investigate the biological role of ELMO1-AS1 in HCC cells.

Results

We uncovered that ELMO1-AS1 was significantly downregulated in HCC tissues, and high expression of ELMO1-AS1 is correlated with optimistic treatment outcome suggesting its potential as an independent prognostic biomarker for HCC. It was also found that overexpression of ELMO1-AS1 in HCC cells suppressed cell proliferation, migration and invasion and engulfment and cell motility 1 (ELMO1) may be a target of ELMO1-AS1.

Conclusion

Our results suggested that macrophage-associated lncRNA ELMO1-AS1 could be a crucial regulator involved in HCC progression and considered as a potential prognostic biomarker and therapeutic target for HCC.

An antisense transcript mediates MALAT1 response in human breast cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) represent a substantial portion of the human transcriptome. LncRNAs present a very stringent cell-type/tissue specificity being potential candidates for therapeutical applications during aging and disease. As example, targeting of MALAT1, a highly conserved lncRNA originally identified in metastatic non-small cell lung cancer, has shown promising results in cancer regression. Nevertheless, the regulation and specificity of MALAT1 have not been directly addressed. Interestingly, MALAT1 locus is spanned by an antisense transcript named TALAM1.

METHODS

Here using a collection of breast cancer cells and in vitro and in vivo migration assays we characterized the dynamics of expression and demonstrated that TALAM1 regulates and synergizes with MALAT1 during tumorigenesis.

RESULTS

Down-regulation of TALAM1 was shown to greatly impact on the capacity of breast cancer cells to migrate in vitro or to populate the lungs of immunocompromised mice. Additionally, we demonstrated that TALAM1 cooperates with MALAT1 in the regulation of the properties guiding breast cancer aggressiveness and malignancy.

CONCLUSIONS

By characterizing this sense/anti-sense pair we uncovered the complexity of MALAT1 locus regulation, describing new potential candidates for cancer targeting.

A highly ordered, nonprotective MALAT1 ENE structure is adopted prior to triplex formation

The 3' end of the ∼7 kb lncRNA MALAT1 contains an evolutionarily and structurally conserved element for nuclear expression (ENE) which confers protection from cellular degradation pathways. Formation of an ENE triple helix is required to support transcript accumulation, leading to persistent oncogenic activity of MALAT1 in multiple cancer types. Though the specific mechanism of triplex-mediated protection remains unknown, the MALAT1 ENE triplex has been identified as a promising target for therapeutic intervention. Interestingly, a maturation step of the nascent lncRNA 3' end is required prior to triplex formation. We hypothesize that disruption of the maturation or folding process may be a viable mechanism of inhibition. To assess putative cotranscriptional ENE conformations prior to triplex formation, we perform microsecond MD simulations of a partially folded ENE conformation and the ENE triplex. We identify a highly ordered ENE structure prior to triplex formation. Extensive formation of U•U base pairs within the large U-rich internal loops produces a global rod-like architecture. We present a three-dimensional structure of the isolated ENE motif, the global features of which are consistent with small angle X-ray scattering (SAXS) experiments. Our structural model represents a nonprotective conformation of the MALAT1 ENE, providing a molecular description useful for future mechanistic and inhibition studies. We anticipate that targeting stretches of U•U pairs within the ENE motif will prove advantageous for the design of therapeutics targeting this oncogenic lncRNA.

Long Non-Coding RNA Function in CD4+ T Cells: What We Know and What Next?

The non-coding genome has previously been regarded as "junk" DNA; however, emerging evidence suggests that the non-coding genome accounts for some of the greater biological complexity observed in mammals. Research into long non-coding RNAs (lncRNAs) has gathered speed in recent years, and a growing body of evidence has implicated lncRNAs in a vast range of cellular functions including gene regulation, chromosome organisation and splicing. T helper cells offer an ideal platform for the study of lncRNAs given they function as part of a complex cellular network and undergo remarkable and finely regulated gene expression changes upon antigenic stimulation. Using various knock down and RNA interaction studies several lncRNAs have been shown to be crucial for T helper cell differentiation, activation and function. Given that RNA targeting therapeutics are rapidly gaining attention, further understanding the mechanistic role of lncRNAs in a T helper context is an exciting area of research, as it may unearth a wide range of new candidate targets for treatment of CD4⁺ mediated pathologies.

LncRNA CASC9 interacts with CPSF3 to regulate TGF-β signaling in colorectal cancer

Background

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer-related death worldwide. Increasing evidence indicates that the deregulation of long noncoding RNAs (lncRNAs) contributes to tumor initiation and progression; however, little is known about the biological role of cancer susceptibility candidate 9 (CASC9) in CRC.

Methods

Novel lncRNAs potentially involved in CRC tumorigenesis were identified from datasets downloaded from The Cancer LncRNome Atlas and The Atlas of Noncoding RNAs in Cancer. The CRC cell lines HCT-116, HCT-116 p53^−/−, SW620, SW480, HT-29, LoVo, LS-174T, and RKO were used. Colony-formation, MTS, cell-cycle, apoptosis, and in-vivo tumorigenesis assays were used to determine the role of CASC9 in CRC cell growth in vitro and in vivo. Potential interaction between CASC9 and cleavage and polyadenylation specificity factor subunit 3 (CPSF3) was evaluated using RNA immunoprecipitation and RNA-protein pull-down assays. RNA-sequencing was performed to analyze gene expression following CASC9 knockdown. RT-qPCR, western blotting, and mRNA decay assays were performed to study the mechanisms involved.

Results

CASC9 was frequently upregulated in CRC, which was correlated with advanced TNM stage, and higher CASC9 levels were associated with poor patient outcomes. Knockdown of CASC9 inhibited growth and promoted apoptosis in CRC cells, whereas ectopic CASC9 expression promoted cell growth in vitro and in vivo. We demonstrated that CPSF3 is a CASC9-interacting protein, and knockdown of CPSF3 mimicked the effects of CASC9 knockdown in CRC cells. Furthermore, we found that CASC9 exerts its oncogenic activity by modulating TGFβ2 mRNA stability and upregulating the levels of TGFβ2 and TERT, resulting in an increase in phosphorylated SMAD3 and activation of TGF-β signaling, and enhanced TERT complex function in CRC cells. Finally, CPSF3 was significantly upregulated in CRC tissues as compared with adjacent or non-adjacent normal colon tissues, and CASC9, CPSF3, and TGFβ2 levels in human CRC tissues were positively correlated.

Conclusions

CASC9 is a promising prognostic predictor for patients with CRC and the CASC9-CPSF3-TGFβ2 axis is a potential therapeutic target for CRC treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1263-3) contains supplementary material, which is available to authorized users.

Non-coding RNAs and chromatin domains

Large-scale transcriptome analyses have identified a variety of non-coding RNAs (ncRNAs) that are not translated into proteins. Many of them are in the nucleus, where they associate with chromatin and regulate its structure and function. Interphase chromosomes are intricately folded into multiple layers and composed of domains. Recent studies using Hi-C technologies have identified a mega-base self-associating chromatin domain: the topologically associating domain (TAD). The domain boundaries are demarcated with the chromatin regulatory proteins CTCF and cohesin, which are often bound to or recruited by ncRNAs. Some ncRNAs form RNA clouds in the nucleus and coordinate the transcription of multiple genes in a chromatin domain. In this review, we describe the emerging link between long ncRNAs and chromatin domains in the nucleus.