Long Noncoding RNA GAS5 Suppresses Cell Growth and Epithelial-Mesenchymal Transition in Osteosarcoma by Regulating the miR-221/ARHI Pathway

Role of long noncoding RNAs in the regulation of epithelial‑mesenchymal transition in osteosarcoma (Review)

Osteosarcoma (OS) is one of the most widespread malignant bone tissue tumors. However, its early diagnosis is difficult, leading to poor prognoses. Long noncoding RNA (lncRNA) can serve as a molecular marker for the early diagnosis and treatment of OS. lncRNAs regulate the epithelial‑mesenchymal transition (EMT) process to control the occurrence and progression of OS. The present review summarizes the studies on lncRNA regulation of OS via the EMT process. A search of the PubMed database yielded 93 published articles since January 2015, of which 73 focused on lncRNA regulation of OS via the EMT process. The present review has classified lncRNAs based on their relationship with tumors (promoting or inhibiting), mechanism of action and naming convention. Most lncRNAs promote OS through EMT and act via microRNA sponging. Previous studies have focused on lncRNAs with known functions, antisense lncRNAs and long intergenic noncoding RNAs. The findings indicated that lncRNAs can regulate the EMT process through various mechanisms to control OS progression. Further studies on specific lncRNAs and their underlying mechanisms will provide insights for the development of strategies for the diagnosis, prevention and treatment of OS.

Epigenetic Regulation by lncRNA GAS5/miRNA/mRNA Network in Human Diseases

The interplay between long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) is crucial in the epigenetic regulation of mRNA and protein expression, impacting the development and progression of a plethora of human diseases, such as cancer, cardiovascular disease, inflammatory-associated diseases, and viral infection. Among the many lncRNAs, growth arrest-specific 5 (GAS5) has garnered substantial attention for its evident role in the regulation of significant biological processes such as proliferation, differentiation, senescence, and apoptosis. Through miRNA-mediated signaling pathways, GAS5 modulates disease progression in a cell-type-specific manner, typically by influencing proteins involved in inflammation and cell death. While GAS5 is recognized as a tumor suppressor in cancer, recent reports highlight its broader regulatory capacity in non-cancerous diseases. Its modulation of protein expression through the GAS5/miRNA network has been shown to both mitigate and exacerbate disease, depending on the specific context. Furthermore, the therapeutic potential of GAS5 manipulation, via knockdown or overexpression, offers promising avenues for targeted interventions across human diseases. This review explores the dualistic impacts of the GAS5/miRNA network in conditions such as cancer, cardiovascular disease, viral infections, and inflammatory disorders. Through the evaluation of current evidence, we aim to provide insight into GAS5's biological functions and its implications for future research and therapeutic development.

Development and validation of a novel endoplasmic reticulum stress-related lncRNAs signature in osteosarcoma

Osteosarcoma (OS) is a cancerous tumor, and its development is greatly influenced by long non-coding RNA (lncRNA). Endoplasmic reticulum stress (ERS) is an essential biological defense process in cells and contributes to the progression of tumors. However, the exact mechanisms remain elusive. This study aims to develop a signature of lncRNAs associated with ERS in OS. This signature will guide the prognosis prediction and the determination of appropriate treatment strategies. The UCSC Xena database collected transcriptional and clinical data of OS and muscle, after identifying ERS differentially expressed genes, we utilized correlation analysis to determine the endoplasmic reticulum stress lncRNAs (ERLs). The Least Absolute Shrinkage and Selection Operator (LASSO) and Cox regression analysis were utilized to develop an ERLs signature. To clarify the fundamental mechanisms controlling gene expression in low and high-risk groups, Gene Set Variation Analysis (GSVA) were conducted. In addition, the distinction between the two groups regarding drug sensitivity and immune-related activity was investigated to determine the immunotherapy effects. Utilizing RT-qPCR, the expression of model lncRNAs in OS cell lines was ascertained. The functional analysis of LINC02298 was carried out through in vitro experiments and pan-cancer analysis. This study successfully constructed an ERLs prognostic signature for OS, which comprised 5 lncRNAs (AC023157.3, AL031673.1, LINC02298, LINC02328, SNHG26). The risk signature predicted overall survival in patients with OS and was confirmed by assessing the validation and whole cohorts. Further, it was discovered that individuals classified as high-risk displayed suppressed immune activation, decreased infiltration of immune cells, and decreased responsiveness to immunotherapy. The RT-qPCR showed that the constructed risk prognosis model is reliable. Experimental validation has demonstrated that LINC02298 can promote OS cells' invasion, migration, and proliferation. In addition, LINC02298 exhibited significant differential expression in many types of cancer. Moreover, LINC02298 is an important biomarker in a variety of tumors. This study established a novel ERLs signature, which successfully predicted the prognosis of OS. The function of LINC02298 in OS was elucidated via in vitro experiments. Therefore, it offers new opportunities for predicting the clinical prognosis of OS and establishes the basis for targeted therapy in OS.

New emerging targets in osteosarcoma therapy: PTEN and PI3K/Akt crosstalk in carcinogenesis

Osteosarcoma (OS) is a malignant bone carcinoma that affects people in childhood and adulthood. The heterogeneous nature and chromosomal instability represent certain characteristics of OS cells. These cancer cells grow and migrate abnormally, making the prognosis undesirable for patients. Conventional and current treatments fail to completely eradicate tumor cells, so new therapeutics targeting genes may be considered. PI3K/Akt is a regulator of events such as growth, cell death, migration, and differentiation, and its expression changes during cancer progression. PTEN reduces PI3K/Akt expression, and its mutations and depletions have been reported in various tumors. Experimental evidence shows that there is upregulation of PI3K/Akt and downregulation of PTEN in OS. Increasing PTEN expression may suppress PI3K/Akt to minimize tumorigenesis. In addition, PI3K/Akt shows a positive association with growth, metastasis, EMT and metabolism of OS cells and inhibits apoptosis. Importantly, overexpression of PI3K/Akt causes drug resistance and radio-resistance and its level can be modulated by miRNAs, lncRNAs and circRNAs. Silencing PI3K/Akt by compounds and drugs can suppress OS. Here, we review in detail the function of the PTEN/PI3K/Akt in OS, revealing its biological function, function in tumor progression, resistance to therapy, and pharmacological significance.

Regulation of the Epithelial to Mesenchymal Transition in Osteosarcoma

The epithelial to mesenchymal transition (EMT) is a cellular process that has been linked to the promotion of aggressive cellular features in many cancer types. It is characterized by the loss of the epithelial cell phenotype and a shift to a more mesenchymal phenotype and is accompanied by an associated change in cell markers. EMT is highly complex and regulated via multiple signaling pathways. While the importance of EMT is classically described for carcinomas-cancers of epithelial origin-it has also been clearly demonstrated in non-epithelial cancers, including osteosarcoma (OS), a primary bone cancer predominantly affecting children and young adults. Recent studies examining EMT in OS have highlighted regulatory roles for multiple proteins, non-coding nucleic acids, and components of the tumor micro-environment. This review serves to summarize these experimental findings, identify key families of regulatory molecules, and identify potential therapeutic targets specific to the EMT process in OS.

Recent advances in machine learning methods for predicting LncRNA and disease associations

Long non-coding RNAs (lncRNAs) are involved in almost the entire cell life cycle through different mechanisms and play an important role in many key biological processes. Mutations and dysregulation of lncRNAs have been implicated in many complex human diseases. Therefore, identifying the relationship between lncRNAs and diseases not only contributes to biologists' understanding of disease mechanisms, but also provides new ideas and solutions for disease diagnosis, treatment, prognosis and prevention. Since the existing experimental methods for predicting lncRNA-disease associations (LDAs) are expensive and time consuming, machine learning methods for predicting lncRNA-disease associations have become increasingly popular among researchers. In this review, we summarize some of the human diseases studied by LDAs prediction models, association and similarity features of LDAs prediction, performance evaluation methods of models and some advanced machine learning prediction models of LDAs. Finally, we discuss the potential limitations of machine learning-based methods for LDAs prediction and provide some ideas for designing new prediction models.

LncRNA GAS5 promotes spermidine‑induced autophagy through the miRNA‑31‑5p/NAT8L axis in pulmonary artery endothelial cells of patients with CTEPH

Chronic thromboembolic pulmonary hypertension (CTEPH) is a leading cause of pulmonary hypertension. The present study investigated the mechanisms of long non-coding RNA growth arrest-specific transcript 5 (GAS5) on spermidine (SP)-induced autophagy. Pulmonary artery endothelial cells (PAECs) were collected from patients with CTEPH and the rat model. Immunofluorescence, Western blots, reverse transcription-quantitative polymerase chain reaction, bioinformatics, rapid amplification of cDNA ends assays, luciferase reporter assays, RNA-binding protein immunoprecipitation assays, GFP-LC3 adenoviruses, tfLC3 assays and transmission electron microscopy were performed. The results revealed that SP-induced autophagy increased GAS5 in PAECs. The upregulation of GAS5 enhanced and the downregulation of GAS5 reversed the roles of SP in PAECs. Furthermore, GAS5 promoted SP-induced autophagy in PAECs by targeting miRNA-31-5p. The miRNA-31-5p mimic suppressed and the inhibitor promoted SP-induced autophagy. Furthermore, N-Acetyltransferase 8 Like (NAT8L) was a target gene of miRNA-31-5p and knockdown of NAT8L inhibited the autophagic levels of PAECs. In vivo, SP treatment decreased miRNA-31-5p and increased NAT8L levels, which was reversed by the knockdown of GAS5. The downregulation of GAS5 abolished the stimulatory role of SP in PAECs of CTEPH rats. In conclusion, GAS5 promoted SP-induced autophagy through miRNA-31-5p/NAT8L signaling pathways in vitro and in vivo and GAS5 may be a promising molecular marker for therapies of CTEPH.

Novel Method of Full-Length RNA-seq That Expands the Identification of Non-Polyadenylated RNAs Using Nanopore Sequencing

The occurrence of diseases displayed transcriptome alteration, including both coding and non-coding transcripts. The third-generation sequencing (TGS) technologies allow for intensive and comprehensive research of the transcriptome. However, the present standard TGS RNA sequencing method is unable to detect many of the non-polyadenylated [non-poly(A)] RNAs. To obtain more complete transcriptome information, we presented a new comprehensive sequencing approach by performing conventional poly(A) RNA-sequencing combined with the sequencing of non-poly(A) RNA fraction which was tailed by poly(U) on HepG2 and HL-7702 cell lines, enabling the detection of multiple categories of non-poly(A) RNAs excluded by the existing standard approach. Moreover, the length distribution of the full-splice match transcripts was longer than that assembled by short-reads, which contributed to characterizing alternative splicing events and provided a comprehensive portrait of transcriptional complexity. Besides the detection of genes with differential expression patterns in the poly(A) library between HepG2 and HL-7702, we also found a cancer-related non-coding gene in the poly(U) data, that is, growth arrest special 5 (GAS5). Collectively, our results suggested that the novel method effectively captured both poly(A) and non-poly(A) transcripts in the tested cell lines and allowed a deeper exploration of the transcriptome.

DSCAM-AS1 promotes cervical carcinoma cell proliferation and invasion via sponging miR-338-3p

Deregulated lncRNA DSCAM-AS1 expression was found in several tumors. However, mechanism and functional role of DSCAM-AS1 in cervical carcinoma remain unknown. DSCAM-AS1 was detected in cervical carcinoma specimens and cells by RT-qPCR. CCK-8, Matrigel transwell, and flow cytometry were conducted to determine cell functions. In this research, we firstly we explored DSCAM-AS1 expression in cervical carcinoma cells and specimens. We revealed that DSCAM-AS1 was upregulated in cervical carcinoma lines (C4-1, Caski, Hela, and Siha) compared to GH329 cells. DSCAM-AS1 was upregulated in cervical carcinoma specimens compared to control no-tumor specimens. Overexpression of DSCAM-AS1 induced cervical carcinoma cell growth and cycle. Moreover, our data revealed that miR-338-3p expression was downregulated in cervical carcinoma cells and specimens. There was a negative correlation between miR-338-3p expression and DSCAM-AS1 expression in cervical carcinoma specimens. Elevated expression of miR-338-3p decreased cervical carcinoma cell growth and cycle and invasion. Furthermore, luciferase reporter analysis revealed that miR-338-3p overexpression suppressed luciferase activity of WT-DSCAM-AS1 vector but not the mut-DSCAM-AS1. Ectopic expression of DSCAM-AS1 decreased miR-338-3p expression in the Siha cell. Overexpression of DSCAM-AS1 promoted cervical carcinoma cell growth and cycle via regulating miR-338-3p. These results suggested that DSCAM-AS1 functions as one oncogene through sponging miR-338-3p in cervical carcinoma.

Long noncoding RNAs (lncRNAs) in HIV-mediated carcinogenesis: Role in cell homeostasis, cell survival processes and drug resistance

There is accruing data implicating long non-coding RNAs (lncRNAs) in the development and progression of non-communicable diseases such as cancer. These lncRNAs have been implicated in many diverse HIV-host interactions, some of which are beneficial to HIV propagation. The virus-host interactions induce the expression of HIV-regulated long non-coding RNAs, which are implicated in the carcinogenesis process, therefore, it is critical to understand the molecular mechanisms that underpin these HIV-regulated lncRNAs, especially in cancer formation. Herein, we summarize the role of HIV-regulated lncRNAs targeting cancer development-related processes including apoptosis, cell cycle, cell survival signalling, angiogenesis and drug resistance. It is unclear how lncRNAs regulate cancer development, this review also discuss recent discoveries regarding the functions of lncRNAs in cancer biology. Innovative research in this field will be beneficial for the future development of therapeutic strategies targeting long non-coding RNAs that are regulated by HIV, especially in HIV associated cancers.

The role of lncRNA-mediated ceRNA regulatory networks in pancreatic cancer

Non-coding RNAs (ncRNAs), which occupy the vast majority of human transcripts are known for their inability to encode proteins. NcRNAs consist of a diverse range of RNA species, including long non-coding RNAs (lncRNAs), which have significant meaning for epigenetic modification, post-transcriptional regulation of target genes, molecular interference, etc. The dysregulation of ncRNAs will mediate the pathogenesis of diverse human diseases, like cancer. Pancreatic cancer, as one of the most lethal malignancies in the digestive system that is hard to make a definite diagnosis at an early clinicopathological stage with a miserable prognosis. Therefore, the identification of potential and clinically applicable biomarker is momentous to improve the overall survival rate and positively ameliorate the prognosis of patients with pancreatic carcinoma. LncRNAs as one kind of ncRNAs exert multitudinous biological functions, and act as molecular sponges, relying on microRNA response elements (MREs) to competitively target microRNAs (miRNAs), thereby attenuating the degradation or inhibition of miRNAs to their own downstream protein-coding target genes, also thus regulating the initiation and progression of neoplasms. LncRNAs, which emerge aforementioned function are called competing endogenous RNAs (ceRNAs). Consequently, abundant research of lncRNAs as potential biomarkers is of critical significance for the molecular diagnosis, targeted therapy, as well as prognosis monitoring of pancreatic cancer.

lncRNA GAS5 promotes pyroptosis in COPD by functioning as a ceRNA to regulate the miR‑223‑3p/NLRP3 axis

Chronic obstructive pulmonary disease (COPD) is characterized by irreversible and progressive airflow limitation and encompasses a spectrum of diseases, including chronic obstructive bronchitis and emphysema. Pyroptosis is a unique form of inflammatory cell death mediated by the activation of caspase-1 and inflammasomes. The long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) is a well-documented tumor suppressor, which is associated with cell proliferation and death in various diseases. The aim of the present study was to evaluate whether lncRNA GAS5 is associated with the pyroptosis in COPD. To create a COPD cell model, MRC-5 cells were treated with 10 µg/ml lipopolysaccharide (LPS) for 48 h. Then the level of pro-caspase 1, caspase 1, IL-1β, IL-18, NLRP3 and cleaved gasdermin D (GSDMD) was examined by western blotting. GAS5 mRNA level was detected by qualitative PCR following LPS treatment in MRC-5 cells. Subsequently, IL-2, IL-6, IL-10 and TNF-α in MRC-5 cells was measured by ELISA. Then the proliferation ability of MRC-5 cells was detected by CCK-8. Cell death was detected by TUNEL assay. LDH release was measured using an LDH Cytotoxicity Assay kit. The Magna RIP kit was used to validate the interaction between GAS5 and miR-223-3p. The present study revealed that increased expression levels of caspase-1, IL-1β, IL-18 and cleaved GSDMD were observed in LPS-treated MRC-5 cells, indicating that pyroptosis is involved in COPD progression. Additionally, LPS induced the increase in GAS5 mRNA expression levels and the release of inflammatory factors (IL-2, IL-6, IL-10 and TNF-α), suggesting that GAS5 is implicated in pyroptosis in COPD. Furthermore, upregulation of GAS5 promoted cell death and inhibited proliferation in the MRC-5 cell line. Additionally, increased GAS5 expression significantly promoted the production of caspase-1, IL-1β, IL-18, cleaved GSDMD and NLR pyrin domain containing protein 3 (NLRP3). A dual-luciferase assay demonstrated that GAS5 could directly bind to microRNA-223-3p (miR-223-3p), and NLRP3 is a direct target of miR-223-3p. Furthermore, GAS5 reduced the expression levels of miR-223-3p, while it increased the expression levels of NLRP3. The present study concluded that lncRNA GAS5 promoted pyroptosis in COPD by targeting the miR-223-3p/NLRP3 axis, implying that GAS5 could be a potential target for COPD.

LDICDL: LncRNA-Disease Association Identification Based on Collaborative Deep Learning

It has been proved that long noncoding RNA (lncRNA) plays critical roles in many human diseases. Therefore, inferring associations between lncRNAs and diseases can contribute to disease diagnosis, prognosis and treatment. To overcome the limitation of traditional experimental methods such as expensive and time-consuming, several computational methods have been proposed to predict lncRNA-disease associations by fusing different biological data. However, the prediction performance of lncRNA-disease associations identification needs to be improved. In this study, we propose a computational model (named LDICDL) to identify lncRNA-disease associations based on collaborative deep learning. It uses an automatic encoder to denoise multiple lncRNA feature information and multiple disease feature information, respectively. Then, the matrix decomposition algorithm is employed to predict the potential lncRNA-disease associations. In addition, to overcome the limitation of matrix decomposition, the hybrid model is developed to predict associations between new lncRNA (or disease) and diseases (or lncRNA). The ten-fold cross validation and de novo test are applied to evaluate the performance of method. The experimental results show LDICDL outperforms than other state-of-the-art methods in prediction performance.

lncRNA DARS-AS1 Promoted Osteosarcoma Progression through Regulating miR-532-3p/CCR7

Background

lncRNAs have been indicated to involve in cell invasion, proliferation, and metastasis. However, function of DARS-AS1 in osteosarcoma remains poorly explored.

Methods

DARS-AS1 and miR-532-3p level were measured using qRT-PCR. CCK-8 assay and cell invasion assay were done to study cell functions. Luciferase reporter assay was performed to study the mechanism about DARS-AS1 and miR-532-3p.

Results

We firstly showed that DARS-AS1 expression is upregulated in 73.5% (25/34) of cases with osteosarcoma. Moreover, DARS-AS1 expression is overexpressed in osteosarcoma specimens than in nontumor samples. The DARS-AS1 is overexpressed in the osteosarcoma cell lines (Saos-2, SOSP-9607, U2OS, and MG-63) compared to hFOB. Overexpression of DARS-AS1 promotes cell growth and invasion in MG-63 osteosarcoma cell. DARS-AS1 plays as one sponge for miR-532-3p in osteosarcoma cell, and miR-532-3p overexpression inhibits luciferase activity of DARS-AS1-WT, not DARS-AS1-MUT in MG-63 cell. Ectopic expression of DARS-AS1 inhibits miR-532-3p expression in MG-63 cell. Furthermore, miR-532-3p expression is downregulated in osteosarcoma specimens compared to in paired nontumor samples. MiR-532-3p expression is downregulated in osteosarcoma cell lines compared to hFOB. MiR-532-3p expression is negatively associated with DARS-AS1 expression in osteosarcoma specimens. miR-532-3p directly regulates CCR7 expression in osteosarcoma cell. Elevated DARS-AS1 expression enhances cell growth and invasion via regulating CCR7.

Conclusions

These data firstly suggested that DARS-AS1 exerted as one oncogene in osteosarcoma partly via regulating miR-532-3p/CCR7.

Identification of an Iron Metabolism-Related lncRNA Signature for Predicting Osteosarcoma Survival and Immune Landscape

Background: Long noncoding RNAs (lncRNAs) act as epigenetic regulators in the process of ferroptosis and iron metabolism. This study aimed to identify an iron metabolism-related lncRNA signature to predict osteosarcoma (OS) survival and the immune landscape.

Methods: RNA-sequencing data and clinical information were obtained from the TARGET dataset. Univariate Cox regression and LASSO Cox analysis were used to develop an iron metabolism-related lncRNA signature. Consensus clustering analysis was applied to identify subtype-based prognosis-related lncRNAs. CIBERSORT was used to analyze the difference in immune infiltration and the immune microenvironment in the two clusters.

Results: We identified 302 iron metabolism-related lncRNAs based on 515 iron metabolism-related genes. The results of consensus clustering showed the differences in immune infiltration and the immune microenvironment in the two clusters. Through univariate Cox regression and LASSO Cox regression analysis, we constructed an iron metabolism-related lncRNA signature that included seven iron metabolism-related lncRNAs. The signature was verified to have good performance in predicting the overall survival, immune-related functions, and immunotherapy response of OS patients between the high- and low-risk groups.

Conclusion: We identified an iron metabolism-related lncRNA signature that had good performance in predicting survival outcomes and showing the immune landscape for OS patients. Furthermore, our study will provide valuable information to further develop immunotherapies of OS.

miR-221/222 as biomarkers and targets for therapeutic intervention on cancer and other diseases: A systematic review

Among deregulated microRNAs (miRs) in human malignancies, miR-221 has been widely investigated for its oncogenic role and as a promising biomarker. Moreover, recent evidence suggests miR-221 as a fine-tuner of chronic liver injury and inflammation-related events. Available information also supports the potential of miR-221 silencing as promising therapeutic intervention. In this systematic review, we selected papers from the principal databases (PubMed, MedLine, Medscape, ASCO, ESMO) between January 2012 and December 2020, using the keywords "miR-221" and the specific keywords related to the most important hematologic and solid malignancies, and some non-malignant diseases, to define and characterize deregulated miR-221 as a valuable therapeutic target in the modern vision of molecular medicine. We found a major role of miR-221 in this view.

Long noncoding RNA Gas5 induces cell apoptosis and inhibits tumor growth via activating the CHOP-dependent endoplasmic reticulum stress pathway in human hepatoblastoma HepG2 cells

In recent years, long noncoding RNAs (lncRNAs) have been demonstrated to be important tumor-associated regulatory factors. LncRNA growth arrest-specific transcript 5 (Gas5) acts as an anti-oncogene in most cancers. Whether Gas5 acts as an oncogene or anti-oncogene in hepatocellular carcinoma (HCC) remains unclear. In the present study, the expression and role of Gas5 in HCC were investigated in vitro and in vivo. Lower expression levels of Gas5 were determined in HCC tissues and cells by quantitative reverse transcription-polymerase chain reaction. Overexpressed Gas 5 lentiviral vectors were constructed to analyze their influence on cell viability, migration, invasion, and apoptosis. Fluorescence in situ hybridization was used to identify the subcellular localization of Gas5. Protein complexes that bound to Gas5 were isolated from HepG2 cells through pull-down experiments and analyzed by mass spectrometry. A series of novel Gas5-interacting proteins were identified and bioinformatics analysis was carried out. These included ribosomal proteins, proteins involved in protein folding, sorting, and transportation in the ER, some nucleases and protein enzymes involved in gene transcription, translation, and other proteins with various functions.78 kDa glucose-regulated protein (GRP78) was identified as a direct target of Gas5 by Rip-qPCR and Western blot analysis assay. Gas5 inhibited HepG2 cell growth and induced cell apoptosis via upregulating CHOP to activate the ER stress signaling pathway. Further studies indicated that the knockdown of CHOP by shRNA partially reversed Gas5-mediated apoptosis in HepG2 cells. Magnetic resonance imaging showed that the ectopic expression of Gas5 inhibited the growth of HCC in nude mice. These findings suggest that Gas5 functions as a tumor suppressor and induces apoptosis through activation of ER stress by targeting the CHOP signal pathway in HCC.

LncRNA GAS5 rs145204276 Polymorphism Reduces Renal Cell Carcinoma Susceptibility in Southern Chinese Population

Objective

Methods

Results

Conclusions

Long Noncoding RNA GAS5: A New Factor Involved in Bone Diseases

Long noncoding RNAs (lncRNAs), as an important type of RNA encoded in the human transcriptome, have shown to regulate different genomic processes in human cells, altering cell type and function. These factors are associated with carcinogenesis, cancer metastasis, bone diseases, and immune system diseases, among other pathologies. Although many lncRNAs are involved in various diseases, the molecular mechanisms through which lncRNAs contribute to regulation of disease are still unclear. The lncRNA growth arrest-specific 5 (GAS5) is a key player that we initially found to be associated with regulating cell growth, differentiation, and development. Further work has shown that GAS5 is involved in the occurrence and prognosis of bone diseases, such as osteoporosis, osteosarcoma, and postosteoporotic fracture. In this review, we discuss recent progress on the roles of GAS5 in bone diseases to establish novel targets for the treatment of bone diseases.

Growth arrest-specific 5 lncRNA as a valuable biomarker of chemoresistance in osteosarcoma

Osteosarcoma is the most common primary malignant bone tumour in children and teenagers, and it is characterised by drug resistance and high metastatic potential. Increasing studies have highlighted the critical roles of long noncoding RNAs (lncRNAs) as oncogenes or tumour suppressors as well as new biomarkers and therapeutic targets in osteosarcoma. The growth arrestspecific 5 (GAS5) lncRNA can function as a tumour suppressor in several cancers. The present study aimed to validate GAS5 and other chemoresistanceassociated lncRNAs as biomarkers in a cohort of primary osteosarcoma samples, to obtain predictive information on resistance or sensitivity to treatment. The GAS5 and a panel of lncRNAs related to chemoresistance [SNGH1, FOXD2-AS1, deleted in lymphocytic leukemia (DLEU2) and LINC00963] were evaluated in a cohort of osteosarcoma patients enrolled at the Careggi University Hospital. Total RNA was extracted from formalin-fixed paraffin-embedded (FFPE) tissue sections and the expression levels of the lncRNAs were quantified by qPCR. A bioinformatic analysis on deposited RNA-seq data was performed to validate the qPCR results. Clustering analysis shows that GAS5 could be linked to the expression of isoforms 02 and 04 of the lncRNA DLEU2, whereas the DLEU2 isoform 08 is linked to the lncRNA LINC00963. We found that GAS5 is significantly increased in patients with a good prognosis and is expressed differently between chemosensitive and chemoresistant osteosarcoma patients. However, the results obtained are not concordant with the in-silico analysis performed on the TARGET osteosarcoma dataset. In the future, we would enlarge the case series, including different disease settings.

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

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

Advances in the Biological Functions and Mechanisms of miRNAs in the Development of Osteosarcoma

Osteosarcoma is one of the most common primary malignant bone tumors, mainly occurring in children and adolescents, and is characterized by high morbidity and poor prognosis. MicroRNAs, a class of noncoding RNAs consisting of 19 to 25 nucleotides, are involved in cell proliferation, invasion, metastasis, and apoptosis to regulate the development and progression of osteosarcoma. Studies have found that microRNAs are closely related to the diagnosis, treatment, and prognosis of osteosarcoma patients and have an important role in improving drug resistance in osteosarcoma. This paper reviews the role of microRNAs in the pathogenesis of osteosarcoma and their clinical value, aiming to provide a new research direction for diagnosing and treating osteosarcoma and achieving a better prognosis.

DIRAS3: An Imprinted Tumor Suppressor Gene that Regulates RAS and PI3K-driven Cancer Growth, Motility, Autophagy, and Tumor Dormancy

DIRAS3 is an imprinted tumor suppressor gene that encodes a 26 kDa GTPase with 60% amino acid homology to RAS, but with a distinctive 34 amino acid N-terminal extension required to block RAS function. DIRAS3 is maternally imprinted and expressed only from the paternal allele in normal cells. Loss of expression can occur in a single "hit" through multiple mechanisms. Downregulation of DIRAS3 occurs in cancers of the ovary, breast, lung, prostate, colon, brain, and thyroid. Reexpression of DIRAS3 inhibits signaling through PI3 kinase/AKT, JAK/STAT, and RAS/MAPK, blocking malignant transformation, inhibiting cancer cell growth and motility, and preventing angiogenesis. DIRAS3 is a unique endogenous RAS inhibitor that binds directly to RAS, disrupting RAS dimers and clusters, and preventing RAS-induced transformation. DIRAS3 is essential for autophagy and triggers this process through multiple mechanisms. Reexpression of DIRAS3 induces dormancy in a nu/nu mouse xenograft model of ovarian cancer, inhibiting cancer cell growth and angiogenesis. DIRAS3-mediated induction of autophagy facilitates the survival of dormant cancer cells in a nutrient-poor environment. DIRAS3 expression in dormant, drug-resistant autophagic cancer cells can serve as a biomarker and as a target for novel therapy to eliminate the residual disease that remains after conventional therapy.

Osteosarcoma and Metastasis

Osteosarcoma is the most common primary bone malignancy in adolescents. Its high propensity to metastasize is the leading cause for treatment failure and poor prognosis. Although the research of osteosarcoma has greatly expanded in the past decades, the knowledge and new therapy strategies targeting metastatic progression remain sparse. The prognosis of patients with metastasis is still unsatisfactory. There is resonating urgency for a thorough and deeper understanding of molecular mechanisms underlying osteosarcoma to develop innovative therapies targeting metastasis. Toward the goal of elaborating the characteristics and biological behavior of metastatic osteosarcoma, it is essential to combine the diverse investigations that are performed at molecular, cellular, and animal levels from basic research to clinical translation spanning chemical, physical sciences, and biology. This review focuses on the metastatic process, regulatory networks involving key molecules and signaling pathways, the role of microenvironment, osteoclast, angiogenesis, metabolism, immunity, and noncoding RNAs in osteosarcoma metastasis. The aim of this review is to provide an overview of current research advances, with the hope to discovery druggable targets and promising therapy strategies for osteosarcoma metastasis and thus to overcome this clinical impasse.

Long noncoding RNA GAS5 in age-related diseases

Aging refers to a natural process and a universal phenomenon in all cells, tissues, organs and the whole organism. Long non-coding RNAs (lncRNAs) are non-coding RNAs with the length of 200 nucleotides. LncRNA growth arrest-specific 5 (lncRNA GAS5) is often down-regulated in cancer. The accumulation of lncRNA GAS5 has been found to be able to inhibit cancer growth, invasion and metastasis, while enhancing the sensitivity of cells to chemotherapy drugs. LncRNA GAS5 can be a signaling protein, which is specifically transcribed under different triggering conditions. Subsequently, it is involved in signal transmission in numerous pathways as a signal node. LncRNA GAS5, with a close relationship to multiple miRNAs, was suggested to be involved in the signaling pathway under three action modes (i.e., signal, bait and guidance). LncRNA GAS5 was found to be involved in different age-related diseases (e.g., rheumatoid arthritis, type 2 diabetes, atherosclerosis, osteoarthritis, osteoporosis, multiple sclerosis, cancer etc.). This study mainly summarized the regulatory effect exerted by lncRNA GAS5 on age-related diseases.

Growth arrest-specific 5 (GAS5) insertion/deletion polymorphism and cancer susceptibility in Asian populations: A meta-analysis

BACKGROUND

Previous studies have reported the association of an insertion/deletion (Ins/Del) polymorphism (rs145204276 AGGCA/-) in the promoter region of growth arrest-specific 5 (GAS5) with the risk of cancer, such as breast cancer, gastric cancer, and hepatocellular carcinoma. However, the results are still controversial. We aimed to clarify the association of GAS5 rs145204276 polymorphism with cancer risk by meta-analysis.

METHODS

PubMed, Embase, Web of Science, China National Knowledge Infrastructure, Wanfang, and Cochrane Library were searched for studies concerning GAS5 and cancer published up to November 25, 2019. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate cancer risk.

RESULTS

A total of 12 case-control studies with 8729 cases and 10,807 controls were included in this meta-analysis. We found that the GAS5 rs145204276 polymorphism was not significantly associated with cancer risk (Del vs Ins: OR = 0.96, 95% CI: 0.81-1.13; Del/Del vs Ins/Ins: OR = 1.00, 95% CI: 0.70-1.43; Ins/Del vs Ins/Ins: OR = 0.92, 95% CI: 0.78-1.08; Ins/Del and Del/Del vs Ins/Ins: OR = 0.93, 95% CI: 0.76-1.13; Del/Del vs Ins/Del and Ins/Ins: OR = 1.04, 95% CI: 0.78-1.38). In the stratified analyses, significant effects on gastric cancer were found (Del vs Ins: OR = 0.79, 95% CI: 0.72-0.86; Del/Del vs Ins/Ins: OR = 0.65, 95% CI: 0.52-0.82; Ins/Del vs Ins/Ins: OR = 0.76, 95% CI: 0.68-0.86; Ins/Del + Del/Del vs Ins/Ins: OR = 0.74, 95% CI: 0.66-0.83; Del/Del vs Ins/Ins + Ins/Del: OR = 0.74, 95% CI: 0.59-0.91).

CONCLUSION

Our meta-analysis showed that GAS5 rs145204276 polymorphisms were not related to overall cancer risk. However, the GAS5 rs145204276 polymorphism may be a protective factor for gastric cancer in the stratification analyses.

LncRNA GACAT1 induces tongue squamous cell carcinoma migration and proliferation via miR-149

Recent studies have observed that lncRNAs (long non‐coding RNAs) are involved in the progression of various tumours including tongue squamous cell carcinoma (TSCC). Recently, a new lnRNA, GACAT1, has been firstly identified in gastric cancer. However, its potential role in TSCC remains unknown. In this reference, we observed that GACAT1 was overexpressed in TSCC samples and cell lines. Of 25 TSCC specimens, GACAT1 expression was overexpressed in 18 patients (18/25, 72%) compared to non‐tumour specimens. Ectopic expression of GACAT1 induced cell growth and migration and promoted epithelial to mesenchymal transition in TSCC. In addition, ectopic expression of GACAT1 decreased miR‐149 expression in SCC1 cell. We observed that miR‐149 expression was down‐regulated in TSCC cell lines. Moreover, we observed that GACAT1 expression was negatively correlated with miR‐149 expression. GACAT1 overexpression induced TSCC cell growth and migration via regulating miR‐149 expression. These data provided that GACAT1 played an oncogenic role in the progression of TSCC partly through modulating miR‐149 expression.

Downregulated lncRNA GAS5 and Upregulated miR-21 Lead to Epithelial-Mesenchymal Transition and Lung Metastasis of Osteosarcomas

Lung is the primary site of osteosarcoma metastasis, but the underlying genetic or epigenetic factors determining lung metastasis of osteosarcoma are unknown. In this study, we report the status of growth arrest specific 5 (GAS5) in lung metastatic osteosarcomas. GAS5 was generally downregulated in osteosarcoma patients (n = 24) compared to healthy controls (n = 10) and even more so in patients with lung metastatic disease(n = 11) compared to the patients without metastasis (n = 13). We also report a role of miR-21 in GAS5-mediated effects. Downregulation of GAS5 in hFOB 1.19 and U2OS osteosarcoma cells enhanced their migration and invasion, along with an upregulated epithelial–mesenchymal transition (EMT), as evidenced by downregulated E-cadherin and upregulated vimentin, ZEB1, and ZEB2. Downregulation of GAS5 also resulted in a significantly increased expression of miR-21. Moreover, downregulation of such elevated miR-21 was found to reverse the effects of GAS5 silencing. miR-21 was also found to be elevated in osteosarcoma patients with its levels particularly high in patients with lung metastasis. Our observations reveal a possible role of GAS5 and miR-21 in lung metastasis of osteosarcoma, presenting them as novel targets for therapy.

LncRNA BCRT1 facilitates osteosarcoma progression via regulating miR-1303/FGF7 axis

Growing studies noted that lncRNA was closely related with the initiation and progression of tumors. However, the role of BCRT1 in the progression of osteosarcoma remains unknown. We noted that BCRT1 is significantly upregulated in osteosarcoma specimens and cells. Elevated expression of BCRT1 promotes cell growth and cell cycle in osteosarcoma cell. Moreover, BCRT1 induces EMT and secretion of inflammatory mediators in osteosarcoma cell. We illustrated that elevated expression of BCRT1 decreases miR-1303 expression in MG-63 cell. The expression of miR-1303 is lower in osteosarcoma specimens than in non-tumor specimens. There is an inverse interrelation between miR-1303 levels and BCRT1 levels in osteosarcoma specimens. Furthermore, we identified FGF7 is one direct target gene of miR-1303 in osteosarcoma cell. Ectopic expression of miR-1303 suppresses FGF7 expression and elevated expression of BCRT1 enhanced FGF7 expression in MG-63 cell. Finally, we illustrated that BCRT1 induces osteosarcoma cell cycle and proliferation and promotes EMT progression and inflammatory mediators secretion via modulating FGF7 expression. Our study suggested that BCRT1 acts as one oncogene in osteosarcoma progression.

The Involvement of Long Non-Coding RNAs in Bone

A harmonious balance between osteoblast and osteoclast activity guarantees optimal bone formation and resorption, pathological conditions affecting the bone may arise. In recent years, emerging evidence has shown that epigenetic mechanisms play an important role during osteoblastogenesis and osteoclastogenesis processes, including long non-coding RNAs (lncRNAs). These molecules are a class of ncRNAs with lengths exceeding 200 nucleotides not translated into protein, that have attracted the attention of the scientific community as potential biomarkers to use for the future development of novel diagnostic and therapeutic approaches for several pathologies, including bone diseases. This review aims to provide an overview of the lncRNAs and their possible molecular mechanisms in the osteoblastogenesis and osteoclastogenesis processes. The deregulation of their expression profiles in common diseases associated with an altered bone turnover is also described. In perspective, lncRNAs could be considered potential innovative molecular biomarkers to help with earlier diagnosis of bone metabolism-related disorders and for the development of new therapeutic strategies.

Role of PRPS2 as a prognostic and therapeutic target in osteosarcoma

AIMS

Osteosarcoma (OS) is the most common primary malignant tumour of the bone. However, further improvement in survival has not been achieved due to a lack of well-validated prognostic markers and more effective therapeutic agents. Recently, the c-Myc-phosphoribosyl pyrophosphate synthetase 2 (PRPS2) pathway has been shown to promote nucleic acid metabolism and cancer cell proliferation in malignant melanoma; phosphorylated mammalian target of rapamycin (p-mTOR) has been upregulated and an effective therapeutic target in OS. However, the p-mTOR-PRPS2 pathway has not been evaluated in OS.

METHODS

In this study, the expression level of PRPS2, p-mTOR and marker of proliferation (MKI-67) was observed in a cohort of specimens (including 236 OS cases and 56 control samples) using immunohistochemistry, and the association between expression level and clinicopathological characteristics of patients with OS was analysed.

RESULTS

PRPS2 protein level, which is related to tumour proliferation, was higher in OS cells (p=0.003) than in fibrous dysplasia, and the higher PRPS2 protein level was associated with a higher tumour recurrence (p=0.001). In addition, our statistical analysis confirmed that PRPS2 is a novel, independent prognostic indicator of OS. Finally, we found that the expression of p-mTOR was associated with the poor prognosis of patients with OS (p<0.05).

CONCLUSIONS

PRPS2 is an independent prognostic marker and a potential therapeutic target for OS.

The critical roles of lncRNAs in the development of osteosarcoma

Osteosarcoma is rare malignancy of childhood and adolescence, with high morbidity and mortality despite accomplishment of diverse therapeutic modalities. Identification of the underlying mechanism of osteosarcoma evolution would help in better management of this rare malignancy. Lots of investigations have described abnormal regulation of long non-coding RNAs (lncRNAs) in clinical specimens of osteosarcoma and the established cell lines. This malignancy has been associated with over-expression of TUG1, LOXL1-AS1, MIR100HG, NEAT1, HULC, ANRIL and a number of other lncRNAs, while under-expression of lots of lncRNAs including LncRNA-p21, FER1L4, GAS5, LncRNA NR_136400 and LINC-PINT. Expression amounts of LUCAT1, LINC00922, SNHG12, FOXC2-AS1 and OIP5-AS1 lncRNAs have been associated with response to a number of chemotherapeutic agents. Taken together, lncRNAs are possible targets for proposing novel advanced therapeutic modalities for osteosarcoma.

EMT-associated microRNAs and their roles in cancer stemness and drug resistance

Epithelial‐to‐mesenchymal transition (EMT) is implicated in a wide array of malignant behaviors of cancers, including proliferation, invasion, and metastasis. Most notably, previou studies have indicated that both cancer stem‐like properties and drug resistance were associated with EMT. Furthermore, microRNAs (miRNAs) play a pivotal role in the regulation of EMT phenotype, as a result, some miRNAs impact cancer stemness and drug resistance. Therefore, understanding the relationship between EMT‐associated miRNAs and cancer stemness/drug resistance is beneficial to both basic research and clinical treatment. In this review, we preliminarily looked into the various roles that the EMT‐associated miRNAs play in the stem‐like nature of malignant cells. Then, we reviewed the interaction between EMT‐associated miRNAs and the drug‐resistant complex signaling pathways of multiple cancers including lung cancer, gastric cancer, gynecologic cancer, breast cancer, liver cancer, colorectal cancer, pancreatic cancer, esophageal cancer, and nasopharyngeal cancer. We finally discussed the relationship between EMT, cancer stemness, and drug resistance, as well as looked forward to the potential applications of miRNA therapy for malignant tumors.

LncRNA GAS5 Silencing Attenuates Oxygen-Glucose Deprivation/Reperfusion-Induced Injury in Brain Microvascular Endothelial Cells via miR-34b-3p-Dependent Regulation of EPHA4

BACKGROUND

The aim of our study was to explore the role of long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) in ischemic stroke using oxygen-glucose deprivation/reperfusion (OGD/R)-induced bEnd.3 cells as in vitro cell model.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were adopted to analyze RNA and protein expression. Cell viability and apoptosis were analyzed by Cell Counting Kit-8 (CCK8) assay and flow cytometry. The levels of nitric oxide (NO) and endothelin-1 (ET-1) in culture supernatant were examined by their matching commercial kits. The intermolecular target interaction was predicted by starBase software and tested by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.

RESULTS

OGD/R-induced apoptosis and dysregulation in vascular endocrine system were largely alleviated by the knockdown of GAS5. GAS5 interacted with microRNA-34b-3p (miR-34b-3p), and GAS5 silencing protected bEnd.3 cells from OGD/R-induced injury partly through up-regulating miR-34b-3p. EPH receptor A4 (EPHA4) was a target of miR-34b-3p. GAS5 acted as the molecular sponge of miR-34b-3p to up-regulate EPHA4 in bEnd.3 cells. GAS5 interference protected against OGD/R-induced damage in bEnd.3 cells partly through down-regulating EPHA4.

CONCLUSION

LncRNA GAS5 knockdown protected brain microvascular endothelial cells bEnd.3 from OGD/R-induced injury depending on the regulation of miR-34b-3p/EPHA4 axis.

LINC01410 accelerated the invasion and proliferation of osteosarcoma by sponging miR-3128

Increasing evidence has shown that lncRNAs are closely correlated with cell apoptosis, autophagy and progression. However, the role of LINC01410 in osteosarcoma has not been verified. We determined that LINC01410 was overexpressed in osteosarcoma specimens and cell lines. The expression of LINC01410 was upregulated in 22 osteosarcoma patients (22/30, 73%) compared to control normal samples. Ectopic expression of LINC01410 promoted the osteosarcoma cell cycle, proliferation and invasion. Overexpression of LINC01410 induced N-cadherin and Vimentin expression and inhibited E-cadherin expression in osteosarcoma cells. LINC01410 acted as a sponge for miR-3128. The results showed that miR-3128 overexpression decreased the luciferase activity of WT-LINC01410 but not mut-LINC01410 in MG-63 cells. Upregulation of LINC01410 expression suppressed miR-3128 expression in MG-63 cells. Moreover, LINC01410 overexpression increased osteosarcoma cell invasion and growth by modulating miR-3128. These data indicated that LINC01410 acted as an oncogene in osteosarcomagenesis and might be a potential new strategy for osteosarcoma treatment.

LncRNA ROR1-AS1 accelerates osteosarcoma invasion and proliferation through modulating miR-504

Long non-coding RNAs (LncRNAs) play vital roles in the progression and development of tumors. However, the functional role of ROR1-AS1 in osteosarcoma has not been investigated. We found that ROR1-AS1 was upregulated in osteosarcoma tissues compared to non-tumor samples. Elevated expression of ROR1-AS1 promoted cyclin D1, PCNA and ki-67 expression and increased cell cycle and growth in MG-63 cell. Moreover, overexpression of ROR1-AS1 induced cell migration in MG-63 cell, promoting N-cadherin and vimentin expression and inhibiting E-cadherin expression. Dual-luciferase assay proved that ROR1-AS1 served as one sponge for miR-504 and ROR1-AS1 overexpression suppressed miR-504 expression in MG-63 cell. ROR1-AS1 expression was lower in osteosarcoma tissues compared to non-tumor samples. Pearson's correlation assay showed a negative correlation between miR-504 and ROR1-AS1 expression. MiR-504 overexpression partly abrogated ROR1-AS1-induced effects on osteosarcoma cell migration and proliferation. These data implied that ROR1-AS1 played as an oncogene and might be a new treatment target for osteosarcoma.

ICLRBBN: a tool for accurate prediction of potential lncRNA disease associations

Growing evidence has elucidated that long non-coding RNAs (lncRNAs) are involved in a variety of complex diseases in human bodies. In recent years, it has become a hot topic to develop effective computational models to identify potential lncRNA-disease associations. In this article, a novel method called ICLRBBN (Internal Confidence-Based Local Radial Basis Biological Network) is proposed to detect potential lncRNA-disease associations by adopting an internal confidence-based radial basis biological network. In ICLRBBN, a novel internal confidence-based collaborative filtering recommendation algorithm was designed first to mine hidden features between lncRNAs and diseases, which guarantees that ICLRBBN can be more effectively applied to predict new diseases. Then, a unique three-layer local radial basis function network consisting of diseases and lncRNAs was constructed, based on which the association probability between diseases and lncRNAs was calculated by combining different characteristics of lncRNAs with local information of diseases. Finally, we compared ICLRBBN with 6 state-of-the-art methods based on two different validation frameworks. Simulation results showed that area under the receiver operating characteristic curve (AUC) values achieved by ICLRBBN outperformed all competing methods. Furthermore, case studies illustrated that ICLRBBN has a promising future as a powerful tool in the practical application of lncRNA-disease association prediction. A web service for prediction of potential lncRNA-disease associations is available at http://leelab2997.cn/.

TNK2-AS1 upregulated by YY1 boosts the course of osteosarcoma through targeting miR-4319/WDR1

Mounting research papers have suggested that long non-coding RNAs (lncRNAs) elicit important functions in the progression of osteosarcoma (OS). This study focused on the role of TNK2-AS1 in OS. TNK2-AS1 was powerfully expressed in OS tissues and cell lines. In addition, TNK2-AS1 downregulation inhibited proliferative, migratory, and invasive capacities while promoting apoptosis in OS cells. miR-4319 was removed by TNK2-AS1 and therefore TNK2-AS1 elevated WDR1 expression in OS cells. miR-4319 had an inhibitory influence on OS progression, while WDR1 was a contributor to OS progression. Rescue assays certified that TNK2-AS1 promoted malignant phenotypes in vitro and the growth in vivo of OS cells by upregulating WDR1. In depth, we found that YY1 accelerated the transcription of TNK2-AS1 in OS cells, and that its role in OS also depended on TNK2-AS1-regulated WDR1. In conclusion, TNK2-AS1 was positively modulated by YY1 and aggravated the development of OS by 'sponging' miR-4319 to elevate WDR1. The findings highlighted that TNK2-AS1 might be a promising target for the treatment of OS.

Long Non-Coding RNA GAS5 Targeting microRNA-21 to Suppress the Invasion and Epithelial-Mesenchymal Transition of Uveal Melanoma

Objective

Human uveal melanoma (UM) is a common ocular malignant tumor with a high risk of metastasis. Emerging evidence indicates that long non-coding RNAs (lncRNAs) are correlated with the development of UM. Here, we aimed to determine the biological significance of lncRNA growth arrest-specific transcript 5 (GAS5) in UM.

Methods

The expression levels of GAS5 and microRNA-21 (miR-21) in UM tissues and cells were detected by qRT-PCR analysis. CCK-8 assay was performed to investigate the viability of UM cells after cell transfections, and the migration and invasion of UM cells were determined by transwell assay. The protein expression levels were detected by Western blot assay. The relationship between miR-21 and GAS5 in UM cells was confirmed by bioinformatics prediction and luciferase report assay.

Results

Our experiments demonstrated that GAS5 was markedly downregulated in UM cells and clinical specimens. Overexpression of GAS5 inhibited, whereas knockdown of GAS5 promoted the viability, migration, and invasion of UM cells. The epithelial-to-mesenchymal transition (EMT) process of UM cells was also suppressed by upregulating of GAS5 and enhanced by downregulating of GAS5. Additionally, as a competitive endogenous RNA (ceRNA), GAS5 directly binded to the oncogenic miR-21 in UM cells, and overexpression of miR-21 attenuated the EMT-suppressing effect of GAS5.

Conclusion

Taken together, our findings suggest that GAS5/miR-21 axis is implicated in the pathogenesis of UM and might serve as a potential therapeutic target.

Noncoding RNAs in drug-resistant pancreatic cancer: A review

Pancreatic cancer is the fourth-leading cause of cancer-related deaths and is expected to be the second-leading cause of cancer-related deaths in Europe and the United States by 2030. The high fatality rate of pancreatic cancer is ascribed to untimely diagnosis, early metastasis and limited responses to both chemotherapy and radiotherapy. Although gemcitabine, 5-fluorouracil and some other drugs can profoundly improve patient prognosis, most pancreatic cancer patients eventually develop drug resistance, leading to poor clinical outcomes. The underlying mechanisms of pancreatic cancer drug resistance are complicated and inconclusive. Interestingly, accumulating evidence has demonstrated that different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play a crucial role in pancreatic cancer resistance to chemotherapy reagents. In this paper, we systematically summarize the molecular mechanism underlying the influence of ncRNAs on the generation and development of drug resistance in pancreatic cancer and discuss the potential role of ncRNAs as prognostic markers and new therapeutic targets for pancreatic cancer.

The Non-Coding RNA GAS5 and Its Role in Tumor Therapy-Induced Resistance

The growth arrest-specific transcript 5 (GAS5) is a >200-nt lncRNA molecule that regulates several cellular functions, including proliferation, apoptosis, invasion and metastasis, across different types of human cancers. Here, we reviewed the current literature on the expression of GAS5 in leukemia, cervical, breast, ovarian, prostate, urinary bladder, lung, gastric, colorectal, liver, osteosarcoma and brain cancers, as well as its interaction with various miRNAs and its effect on therapy-related resistance in these malignancies. The general consensus is that GAS5 acts as a tumor suppressor across different tumor types and that its up-regulation results in tumor sensitization to chemotherapy or radiotherapy. GAS5 seems to play a previously unappreciated, but significant role in tumor therapy-induced resistance.

LINC01133: an emerging tumor-associated long non-coding RNA in tumor and osteosarcoma

Emerging evidence suggested that long non-coding RNAs (lncRNAs) play pivotal roles in tumorigenesis. LINC01133 is a newly identified lncRNA first discovered as an oncogene in lung squamous cell carcinoma. Subsequent studies further demonstrated this lncRNA was deregulated in a wide spectrum of tumors, including colorectal, gastric, lung, and pancreatic ductal adenocarcinoma as well as osteosarcoma and hepatocellular carcinoma. Intriguingly, this lncRNA exerted oncogenic or tumor-suppressive action in a tissue-dependent manner. This review sought to summarize our current understanding concerning the deregulation of LINC01133 in human tumors in relation to its molecular mechanisms and cellular functions. The clinical utilization of LINC01133 as a potential prognostic biomarker and a treatment target is also discussed.

Clinical significance of long non-coding RNA DUXAP8 and its protein coding genes in hepatocellular carcinoma

Backgrounds: Hepatocellular carcinoma (HCC) is a lethal malignancy worldwide that is difficult to diagnose during the early stages and its tumors are recurrent. Long non-coding RNAs (lncRNAs) have increasingly been associated with tumor biomarkers for diagnosis and prognosis. This study attempts to explore the potential clinical significance of lncRNA DUXAP8 and its co-expression related protein coding genes (PCGs) for HCC.

Method: Data from a total of 370 HCC patients from The Cancer Genome Atlas were utilized for the analysis. DUXAP8 and its top 10 PCGs were explored for their diagnostic and prognostic implications for HCC. A risk score model and nomogram were constructed for prognosis prediction using prognosis-related genes and DUXAP8. Molecular mechanisms of DUXAP8 and its PCGs involved in HCC initiation and progression were investigated. Then, potential target drugs were identified using genome-wide DUXAP8-related differentially expressed genes in a Connectivity Map database.

Results: The top 10 PCGs were identified as: RNF2, MAGEA1, GABRA3, MKRN3, FAM133A, MAGEA3, CNTNAP4, MAGEA6, MALRD1, and DGKI. Diagnostic analysis indicated that DUXAP8, MEGEA1, MKRN3, and DGKI show diagnostic implications (all area under curves ≥0.7, p≤0.05). Prognostic analysis indicated that DUXAP8 and RNF2 had prognostic implications for HCC (adjusted p=0.014 and 0.008, respectively). The risk score model and nomogram showed an advantage for prognosis prediction. A total of 3 target drugs were determined: cinchonine, bumetanide and amiprilose and they may serve as potential therapeutic targets for HCC.

Conclusion: Functioning as an oncogene, DUXAP8 is overexpressed in tumor tissue and may serve as both a diagnostic and prognosis biomarker for HCC. MEGEA1, MKRN3, and DGKI maybe potential diagnostic biomarkers and DGKI may also be potentially prognostic biomarkers for HCC.

Comparative analysis of long noncoding RNAs in long-lived mammals provides insights into natural cancer-resistance

Mouse and rats are staple model organisms that have been traditionally used for oncological studies; however, their short lifespan and highly prone to cancers limit their utilizationsin understanding the mechanisms of cancer resistance. In recent years, several studies of the non-standard long-lived mammalian species like naked mole rat (NMR) have provided new insights of mechanisms in natural anti-cancer. How long-lived species genetically maintain longevity and cancer-resistance remains largely elusive. To better understand the underlying anti-cancer mechanisms in long-lived mammals, we genome widely identified long noncoding RNA (lncRNA) transcripts of two longevous mammals, bowhead whale (BW, Balaena mysticetus) and Brandt's bat (BB, Myotis brandtii) and featured their sequence traits, expression patterns, and their correlations with cancer-resistance. Similar with naked mole rat (NMR, Heterocephalus glaber), the most long-lived rodent, BW and BB lncRNAs show low sequence conservation and dynamic expressions among tissues and physiological stages. By utilizing k-mers clustering, 75-136 of BW, BB and NMR lncRNAs were found in close relation (Pearson's r ≥0.9, p < 0.01) with human ageing diseases related lncRNAs (HAR-Lncs). In addition, we observed thousands of BB and BW lncRNAs strongly co-expressed (r > 0.8 or r <-0.8, p < 0.01) with potential tumour suppressors, indicating that lncRNAs are potentially involved in anti-cancer regulation in long-lived mammals. Our study provides the basis for lncRNA researches in perspectives of evolution and anti-cancer studies. Abbreviations: BW: bowhead whale; BB: Brandt's bat; NMR: naked mole rat; LLM: long-lived mammal; HTS: human tumour-suppressors; PTS: potential tumour suppressor; ARD: ageing related diseases; HAR-Lncs: lncRNAs that related with human ageing diseases; Kmer-lncs: lncRNAs in long-lived mammal species that corelated (Pearson'sr ≥0.9, p < 0.01) with the 10 HAR-Lncs by k-mers clustering; All-lncs: all the lncRNAs in long-lived mammal species; SDE-lncs: significant differentially expressed lncRNAs.

MiR-663a, regulated by lncRNA GAS5, contributes to osteosarcoma development through targeting MYL9

Osteosarcoma is characterized by high malignancy and high metastasis rate, resulting in high mortality and disability. MiR-663a has been reported in a variety of tumors to promote tumorigenesis. However, miR-663a has not been reported in the pathogenesis of osteosarcoma. Bioinformatics analysis and experiments including real-time quantitative polymerase chain reaction (RT-qPCR), luciferase reporter, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Western blot, RNA immunoprecipitation, and flow cytometry assay were applied to explore the function and mechanism of miR-663a in MG63, U2OS, Saos-2, SF-86, and hFOB1.19 cells. In this study, we found that miR-663a is highly expressed in osteosarcoma. At the same time, we discovered that miR-663a facilitates cell proliferation and migration, whereas suppresses cell apoptosis in osteosarcoma. Through a series of biological experiments, it was found that miR-663a regulates the cellular process in osteosarcoma by modulating the expression of MYL9. In addition, we also found that long noncoding RNA (lncRNA) GAS5 serves as a molecular sponge for miR-663a and regulates the progression of osteosarcoma via the ceRNA mechanism. We uncover that miR-663a promotes osteosarcoma development through targeting MYL9, which was regulated by lncRNA GAS5.

Long non-coding RNA GAS5 in human cancer

Long non-coding RNAs (lncRNAs) constitute a group of >200-nucleotide ncRNA molecules. lncRNAs regulate several cell functions, such as proliferation, apoptosis, invasion and metastasis. Meanwhile, lncRNAs are abnormally expressed in human malignancies, where they suppress or promote tumor growth. The present study focused on growth arrest-specific transcript 5 (GAS5), a well-known lncRNA that acts as a tumor suppressor but is suppressed in multiple types of cancer, including mammary carcinoma, prostate cancer, colorectal cancer, gastric cancer, melanoma, esophageal squamous cell carcinoma, lung cancer, ovarian cancer, cervical cancer, gliomas, osteosarcoma, pancreatic cancer, bladder cancer, kidney cancer, papillary thyroid carcinoma, neuroblastoma, endometrial cancer and liver cancer. Notably, GAS5 is overexpressed in liver cancer, potentially functioning as an oncogene. In the present study, the diagnostic and therapeutic roles of GAS5 in different tumors were reviewed, with a summary of the potential clinical application of the lncRNA, which may help identify novel study directions for GAS5.

Long non-coding RNA SCARNA2 induces cutaneous squamous cell carcinoma progression via modulating miR-342-3p expression

BACKGROUND

Long non-coding RNAs (lncRNAs) play important roles in the progression of tumors. However, the function and expression of SCARNA2 in cutaneous squamous cell carcinoma (cSCC) is still unreported.

METHODS

A quantitative polymerase chain reaction was applied to study the expression of SCARNA2 and miR-342-3p. Cell counting kit-8, flow cytometry and transwell assays were performed to study cell growth, cycle and cell invasion.

RESULTS

We found that SCARNA2 expression is up-regulated in cSCC cell lines and SCARNA2 expression is higher in cSCC tissues than in adjacent non-tumor specimens. Ectopic expression of SCARNA2 promoted cell growth, cell cycle and invasion in SCC13 cells. In addition, the data indicate that miR-342-3p expression is down-regulated in cSCC cell lines and miR-342-3p is down-regulated in cSCC tissues compared to adjacent non-tumor specimens. We showed that the SCARNA2 expression is negatively associated with miR-342-3p in cSCC. Moreover, we noted that SCARNA2 sponges miR-342-3p expression in cSCC cells. Overexpression of SCARNA2 suppressed the miR-342-3p expressed in SCC13 cells. We found that elevated expression of SCARNA2 promotes cell growth, cell cycle and invasion via regulating miR-342-3p expression in SCC13 cells.

CONCLUSIONS

These data suggest that SCARNA2 acts in an oncogenic role and may be a potential target for cSCC.

Long noncoding RNA GAS5 promotes microglial inflammatory response in Parkinson's disease by regulating NLRP3 pathway through sponging miR-223-3p

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Neuroinflammation induced by microglia plays an important role in the pathogenesis of PD. Long noncoding RNA GAS5 was showed to have significant effects on regulating inflammatory response. Here, we aim to investigate the effects of GAS5 on the inflammatory response of PD, and the underlying mechanism. An in vivo model of PD was established in C57BL/6 mice by rotenone and an in vitro cell model was conducted on microglia by lipopolysaccharide (LPS). Our results indicated that GAS5 was upregulated in tissues in a mice model of PD and microglia activated by LPS. Gain- and loss- of functional experiments demonstrated that GAS5 promoted the inflammation of microglia in vitro. Besides, the knockdown of GAS5 repressed the PD progression in vivo. Mechanistically, GAS5 positively regulated the NLRP3 expression via competitively sponging miR-223-3p. Overall, our finding illuminates that GAS5 accelerates PD progression through targeting miR-223-3p/NLRP3 axis.

LncRNA ILF3-AS1 mediated the occurrence of epilepsy through suppressing hippocampal miR-212 expression

Increased expression of some matrix metalloproteinases (MMPs) is closely associated with epilepsy. However, factors that promote their expression have not been clarified. Long noncoding RNAs (lncRNAs) play crucial roles in the development of human diseases, including various cancers, but its potential function in temporal lobe epilepsy (TLE) has remained unexplored. In this study, we showed that hippocampal and serum ILF3-AS1 levels are higher in TLE patients than in matched controls. Interleukin (IL)-1β and tumor necrosis factor (TNF)-α induced ILF3-AS1 expression in astrocytes, while ectopic expression of ILF3-AS1 enhanced IL-6 and TNF-α expression. Ectopic ILF3-AS1 in astrocytes also increased expression of MMP2, MMP3, MMP9 and MMP14, but suppressed expression of miR-212. Consistent with that finding, miR-212 levels were lower in the hippocampus and serum of TLE patients than their controls. This suggests that ILF3-AS1 promotes expression of inflammatory cytokines and MMPs by targeting miR-212 and that ILF3-AS1 plays a crucial role in the development of TLE.