Long noncoding RNA GAS5 promotes bladder cancer cells apoptosis through inhibiting EZH2 transcription

LncRNA MEG3 Inhibits the Epithelial-mesenchymal Transition of Bladder Cancer Cells through the Snail/E-cadherin Axis

OBJECTIVE

This study aimed to investigate the role of the long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) in the epithelial-mesenchymal transition (EMT) of bladder cancer cells and the potential mechanisms.

METHODS

Cell invasion, migration, and wound healing assays were conducted to assess the effects of MEG3 on the invasive and migratory capabilities of bladder cancer cells. The expression levels of E-cadherin were measured using Western blotting, RT-qPCR, and dual luciferase reporter assays. RNA immunoprecipitation and pull-down assays were performed to investigate the interactions between MEG3 and its downstream targets.

RESULTS

MEG3 suppressed the invasion and migration of bladder cancer cells and modulated the transcription of E-cadherin. The binding of MEG3 to the zinc finger region of the transcription factor Snail prevented its ability to transcriptionally repress E-cadherin. Additionally, MEG3 suppressed the phosphorylation of extracellular regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and P38, thereby decreasing the expression of Snail and stimulating the expression of E-cadherin.

CONCLUSION

MEG3 plays a vital role in suppressing the EMT in bladder cancer cells, indicating its potential as a promising therapeutic target for the treatment of bladder cancer.

Serum EZH2 is a novel biomarker for bladder cancer diagnosis and prognosis

Objective

The primary objective of this study was to examine the levels of serum EZH2 in patients diagnosed with bladder cancer, and subsequently evaluate its potential as a biomarker for both the diagnosis and prognosis of bladder cancer.

Methods

Blood samples were obtained from 115 bladder cancer patients and 115 healthy persons. We measured the EZH2 concentrations in the serum of these subjects via enzyme-linked immunosorbent assay (ELISA). To assess the diagnostic performance of serum EZH2 in detecting bladder cancer, we plotted receiver operating characteristic (ROC) curves and calculated their corresponding area under the curve (AUC). We also used the Cox regression model and log-rank test to investigate the correlation between EZH2 levels and clinicopathological characteristics, and survival rates of bladder cancer patients.

Results

Serum EZH2 levels were significantly higher in bladder cancer patients when compared to those in healthy persons. Serum EZH2 levels exhibited a significant correlation with TNM stage, lymph node metastasis, muscle invasion, and tumor size. At a cutoff value of 8.23 ng/mL, EZH2 was able to differentiate bladder cancer patients from healthy persons, with an AUC of 0.87, a sensitivity of 81.31%, and a specificity of 78.42%. High EZH2 levels correlated with poor overall survival rates and progression-free survival rates of bladder cancer patients.

Conclusions

Serum EZH2 levels were elevated in bladder cancer patients, and patients with higher serum EZH2 levels exhibited a poorer prognosis. This indicates that serum EZH2 could be a novel biomarker for bladder cancer diagnosis and prognosis. Such findings could improve the prognosis of bladder cancer patients by facilitating early detection and continuous monitoring.

Recent progress and the emerging role of lncRNAs in cancer drug resistance; focusing on signaling pathways

It is becoming more and more apparent that many of the genetic alterations associated with cancer are located in areas that do not encode proteins. lncRNAs are a class of RNAs that do not code for proteins but play a crucial role in maintaining cell function and regulating various cellular processes. By doing this, they have recently introduced what may be a brand-new and essential layer of biological control. These have more than 200 nucleotides and are linked to several diseases; as a result, they have become potential tools for therapeutic intervention. Emerging technologies suggest the presence of mutations on genomic loci that give rise to lncRNAs rather than proteins in a disease as complex as cancer. These lncRNAs play essential parts in gene regulation, which impacts several cellular homeostasis processes, including proliferation, survival, migration, and genomic stability. The leading cause of death in the world today is cancer. Delays in diagnosis and a lack of standard and efficient treatments are the leading causes of the high death rate. Clinically, surgery is frequently used successfully to remove cancers that have not spread, but it is less successful in treating metastatic cancer, which has a drastically lower chance of survival. Chemotherapeutic drugs are a typical therapy to treat the cancer that has spread to other organs. Drug resistance to chemotherapy, however, presents a significant challenge to achieving positive outcomes and is frequently the cause of treatment failure. A substantial barrier to progress in medical oncology is cancer drug resistance. Resistance can develop clinically either before or after cancer treatment. According to this study, lncRNAs influence drug resistance through several different methods. LncRNAs often impact drug resistance by controlling the expression of a few intermediary regulatory variables rather than by directly affecting drug resistance. Additionally, lncRNAs have a variety of roles in cancer medication resistance. Most lncRNAs induce drug resistance when overexpressed; however, other lncRNAs have inhibitory effects. This study provides an overview of the current understanding of lncRNAs, relevance to cancer, and potential therapeutic applications.

Intron Editing Reveals SNORD-Dependent Maturation of the Small Nucleolar RNA Host Gene GAS5 in Human Cells

The GAS5 gene encodes a long non-coding RNA (lncRNA) and intron-located small nucleolar RNAs (snoRNAs). Its structure, splice variants, and diverse functions in mammalian cells have been thoroughly investigated. However, there are still no data on a successful knockout of GAS5 in human cells, with most of the loss-of-function experiments utilizing standard techniques to produce knockdowns. By using CRISPR/Cas9 to introduce double-strand breaks in the terminal intronic box C/D snoRNA genes (SNORDs), we created monoclonal cell lines carrying continuous deletions in one of the GAS5 alleles. The levels of GAS5-encoded box C/D snoRNAs and lncRNA GAS5 were assessed, and the formation of the novel splice variants was analyzed. To comprehensively evaluate the influence of specific SNORD mutations, human cell lines with individual mutations in SNORD74 and SNORD81 were obtained. Specific mutations in SNORD74 led to the downregulation of all GAS5-encoded SNORDs and GAS5 lncRNA. Further analysis revealed that SNORD74 contains a specific regulatory element modulating the maturation of the GAS5 precursor transcript. The results demonstrate that the maturation of GAS5 occurs through the m6A-associated pathway in a SNORD-dependent manner, which is a quite intriguing epitranscriptomic mechanism.

Exploring GAS5's impact on prostate cancer: Recent discoveries and emerging paradigms

Novel treatment targets must be discovered to improve the results for patients with prostate cancer, which continues to be a significant worldwide health problem. Growth Arrest-Specific 5 (GAS5) is a long non-coding RNA (lncRNA) that has emerged as a promising target. GAS5 is a non-coding RNA that is a tumour suppressor in many different cancers by reducing cell proliferation and increasing apoptosis. GAS5 influences cell cycle control and apoptosis via interactions with important signalling pathways and microRNAs, as has been shown by recent studies. Furthermore, GAS5 has attracted interest for its diagnostic and prognostic potential in prostate cancer. GAS5 expression is a promising biomarker for disease classification and individualized treatment approaches because of its association with clinicopathological characteristics such as tumour stage, Gleason score, and metastatic potential. Preclinical models have revealed encouraging anticancer benefits from experimental techniques employing GAS5 overexpression or synthetic analogues, indicating the possibility of translational treatments. Whether GAS5 can be used as a diagnostic biomarker and therapeutic target might lead to more effective and individualized ways to fight prostate cancer, improving patient outcomes and quality of life. To utilize its potential for therapy and establish it as a useful addition to the clinical arsenal against this pervasive malignancy, more investigation into the complex molecular pathways of GAS5 in prostate cancer is essential. This review highlights the recent advancements and insights into the role of GAS5 in prostate cancer pathogenesis and progression.

Integrative Genomic Analyses Identify LncRNA Regulatory Networks across Pediatric Leukemias and Solid Tumors

Long noncoding RNAs (lncRNA) play an important role in gene regulation and contribute to tumorigenesis. While pan-cancer studies of lncRNA expression have been performed for adult malignancies, the lncRNA landscape across pediatric cancers remains largely uncharted. Here, we curated RNA sequencing data for 1,044 pediatric leukemia and extracranial solid tumors and integrated paired tumor whole genome sequencing and epigenetic data in relevant cell line models to explore lncRNA expression, regulation, and association with cancer. A total of 2,657 lncRNAs were robustly expressed across six pediatric cancers, including 1,142 exhibiting histotype-elevated expression. DNA copy number alterations contributed to lncRNA dysregulation at a proportion comparable to protein coding genes. Application of a multidimensional framework to identify and prioritize lncRNAs impacting gene networks revealed that lncRNAs dysregulated in pediatric cancer are associated with proliferation, metabolism, and DNA damage hallmarks. Analysis of upstream regulation via cell type-specific transcription factors further implicated distinct histotype-elevated and developmental lncRNAs. Integration of these analyses prioritized lncRNAs for experimental validation, and silencing of TBX2-AS1, the top-prioritized neuroblastoma-specific lncRNA, resulted in significant growth inhibition of neuroblastoma cells, confirming the computational predictions. Taken together, these data provide a comprehensive characterization of lncRNA regulation and function in pediatric cancers and pave the way for future mechanistic studies.

SIGNIFICANCE

Comprehensive characterization of lncRNAs in pediatric cancer leads to the identification of highly expressed lncRNAs across childhood cancers, annotation of lncRNAs showing histotype-specific elevated expression, and prediction of lncRNA gene regulatory networks.

GAS5 silencing attenuates hypoxia-induced cardiomyocytes injury by targeting miR-21/PTEN

INTRODUCTION

Myocardial hypoxia is an important factor causing myocardial infarction (MI). Interestingly, many unknown factors in the molecular mechanism of MI remain unclear. Our study explored the role of lncRNA growth arrest-specific 5 (GAS5) in cell injury under hypoxia.

METHODS

AS5 expression was assessed in MI and human cardiomyocytes under hypoxia through RT-qPCR assay. Methyl thiazolyl tetrazolium assay, flow cytometry assay, and transwell assay was carried out for cell viability, cell apoptosis, cell migration, and invasion, respectively. The regulatory target of GAS5 was explored through a dual-luciferase reporter assay.

RESULTS

Our findings indicated that the upregulation of GAS5 was related to hypoxia. Downregulation of GAS5 expression could decrease hypoxia-induced cell apoptosis and increase cell migration and invasion. Moreover, GAS 5 targeted miR-21, which regulated the phosphatase and tension homology deleted on chromosome ten gene (PTEN) expression. Furthermore, the knockdown of miR-21 eliminated the effect of GAS5 silencing on cell injury.

CONCLUSION

These results indicated that lncRNA GAS5 silencing decreased cardiomyocyte injury by hypoxia-induced through regulating miR-21/PTEN.

Epigenetic and Immunological Features of Bladder Cancer

Bladder cancer (BLCA) is one of the most common types of malignant tumors of the urogenital system in adults. Globally, the incidence of BLCA is more than 500,000 new cases worldwide annually, and every year, the number of registered cases of BLCA increases noticeably. Currently, the diagnosis of BLCA is based on cystoscopy and cytological examination of urine and additional laboratory and instrumental studies. However, cystoscopy is an invasive study, and voided urine cytology has a low level of sensitivity, so there is a clear need to develop more reliable markers and test systems for detecting the disease with high sensitivity and specificity. Human body fluids (urine, serum, and plasma) are known to contain significant amounts of tumorigenic nucleic acids, circulating immune cells and proinflammatory mediators that can serve as noninvasive biomarkers, particularly useful for early cancer detection, follow-up of patients, and personalization of their treatment. The review describes the most significant advances in epigenetics of BLCA.

Roles of non-coding RNAs in the metabolism and pathogenesis of bladder cancer

Bladder cancer (BC) is featured as the second most common malignancy of the urinary tract worldwide with few treatments leading to high incidence and mortality. It stayed a virtually intractable disease, and efforts to identify innovative and effective therapies are urgently needed. At present, more and more evidence shows the importance of non-coding RNA (ncRNA) for disease-related study, diagnosis, and treatment of diverse types of malignancies. Recent evidence suggests that dysregulated functions of ncRNAs are closely associated with the pathogenesis of numerous cancers including BC. The detailed mechanisms underlying the dysregulated role of ncRNAs in cancer progression are still not fully understood. This review mainly summarizes recent findings on regulatory mechanisms of the ncRNAs, long non-coding RNAs, microRNAs, and circular RNAs, in cancer progression or suppression and focuses on the predictive values of ncRNAs-related signatures in BC clinical outcomes. A deeper understanding of the ncRNA interactive network could be compelling framework for developing biomarker-guided clinical trials.

The Diagnostic and Therapeutic Role of snoRNA and lincRNA in Bladder Cancer

Bladder cancer is one of the most common malignancies of the urinary tract and can be divided into non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC). Although the means of diagnosis and treatment have continually improved in recent years, the recurrence rate of bladder cancer remains high, and patients with MIBC typically have an unfavourable prognosis and a low quality of life. Emerging evidence demonstrates that long noncoding RNAs play a crucial role in the carcinogenesis and progression of bladder cancer. Long intergenic noncoding RNAs (lincRNAs) are a subgroup of long noncoding RNAs (lncRNAs) that do not overlap protein-coding genes. The potential role of lincRNAs in the regulation of gene expression has been explored in depth in recent years. Small nucleolar RNAs (snoRNAs) are a class of noncoding RNAs (ncRNAs) that mainly exist in the nucleolus, are approximately 60-300 nucleotides in length, and are hosted inside the introns of genes. Small nucleolar RNA host genes (SNHGs) have been associated with the origin and development of bladder cancer. In this review, we aim to comprehensively summarize the biological functions of these molecules in bladder cancer.

Tumor Suppressive Effects of GAS5 in Cancer Cells

In recent years, long non-coding RNAs (lncRNAs) have been shown to play important regulatory roles in cellular processes. Growth arrests specific transcript 5 (GAS5) is a lncRNA that is highly expressed during the cell cycle arrest phase but is downregulated in actively growing cells. Growth arrests specific transcript 5 was discovered to be downregulated in several cancers, primarily solid tumors, and it is known as a tumor suppressor gene that regulates cell proliferation, invasion, migration, and apoptosis via multiple molecular mechanisms. Furthermore, GAS5 polymorphism was found to affect GAS5 expression and functionality in a cell-specific manner. This review article focuses on GAS5’s tumor-suppressive effects in regulating oncogenic signaling pathways, cell cycle, apoptosis, tumor-associated genes, and treatment-resistant cells. We also discussed genetic polymorphisms of GAS5 and their association with cancer susceptibility.

The long non-coding RNA LIMT inhibits metastasis of hepatocellular carcinoma and is suppressed by EGF signaling

Background

The long non-coding RNA LIMT (lncRNA inhibiting metastasis) acts as a tumor suppressor factor in some cancers. However, the biological role of LIMT in hepatocellular carcinoma (HCC) has not been explored.

Methods and Results

Quantitative real-time PCR was performed to evaluate the expression of LIMT in HCC tissue. The effects of LIMT on tumor growth and metastasis were assessed by in vitro experiments, including colony formation and transwell assays, and in vivo in nude mouse models. Western blot analysis was used to evaluate the expression levels of proteins associated with epithelial-mesenchymal transition (EMT). LIMT expression was significantly lower in HCC than in normal liver tissue. Functionally, overexpression of LIMT repressed the proliferation, invasion, and EMT of HCC cells, while LIMT knockdown increased proliferation, invasion, and EMT of HCC cells in vitro. Furthermore, LIMT overexpression suppressed HCC growth and metastasis while silencing of LIMT had an opposite effect in vivo. Finally, LIMT overexpression reversed EGF-induced EMT.

Conclusions

Our results suggest that LIMT could play an anti-cancer effect in HCC and might be a potential novel therapeutic target in HCC.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11033-022-07325-0.

The various regulatory functions of long noncoding RNAs in apoptosis, cell cycle, and cellular senescence

Long noncoding RNAs (lncRNAs) are a group of noncoding cellular RNAs involved in significant biological phenomena such as differentiation, cell development, genomic imprinting, adjusting the enzymatic activity, regulating chromosome conformation, apoptosis, cell cycle, and cellular senescence. The misregulation of lncRNAs interrupting normal biological processes has been implicated in tumor formation and metastasis, resulting in cancer. Apoptosis and cell cycle, two main biological phenomena, are highly conserved and intimately coupled mechanisms. Hence, some cell cycle regulators can influence both programmed cell death and cell division. Apoptosis eliminates defective and unwanted cells, and the cell cycle enables cells to replicate themselves. The improper regulation of apoptosis and cell cycle contributes to numerous disorders such as neurodegenerative and autoimmune diseases, viral infection, anemia, and mainly cancer. Cellular senescence is a tumor-suppressing response initiated by environmental and internal stress factors. This phenomenon has recently attained more attention due to its therapeutic implications in the field of senotherapy. In this review, the regulatory roles of lncRNAs on apoptosis, cell cycle, and senescence will be discussed. First, the role of lncRNAs in mitochondrial dynamics and apoptosis is addressed. Next, the interaction between lncRNAs and caspases, pro/antiapoptotic proteins, and also EGFR/PI3K/PTEN/AKT/mTORC1 signaling pathway will be investigated. Furthermore, the effect of lncRNAs in the cell cycle is surveyed through interaction with cyclins, cdks, p21, and wnt/β-catenin/c-myc pathway. Finally, the function of essential lncRNAs in cellular senescence is mentioned.

Phytochemicals mediated modulation of microRNAs and long non-coding RNAs in cancer prevention and therapy

MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are two main categories of noncoding RNAs (ncRNAs) that can influence essential biological functions in various ways, as well as their expression and function are tightly regulated in physiological homeostasis. Additionally, the dysregulation of these ncRNAs seems to be crucial to the pathogenesis of human diseases. The latest findings indicate that ncRNAs execute vital roles in cancer initiation and progression, and the cancer phenotype can be reversed by modulating their expression. Available scientific discoveries suggest that phytochemicals such as polyphenols, alkaloids, terpenoids, and organosulfur compounds can significantly modulate multiple cancer-associated miRNAs and lncRNAs, thereby inhibiting cancer initiation and development. However, despite promising outcomes of experimental research, only a few clinical trials are currently being conducted to evaluate the therapeutic effectiveness of these compounds. Nevertheless, understanding phytochemical-mediated ncRNA regulation in cancer and the underlying molecular mechanisms on tumor pathophysiology can aid in the development of novel therapeutic strategies to combat this deadly disease.

Knockdown of long noncoding RNA GAS5 reduces vascular smooth muscle cell apoptosis by inactivating EZH2-mediated RIG-I signaling pathway in abdominal aortic aneurysm

Background

Abdominal aortic aneurysm (AAA), an irreversible cardiovascular disease prevalent in the artery, causes the increase of the aneurysm diameter over time, and is a fatal phenomenon inducing sidewall rupture. Long noncoding RNAs (lncRNAs) serve as promising biomarkers for AAA. In the present study, we sought to define the role of lncRNA growth-arrest-specific transcript 5 (GAS5) in growth of smooth muscle cells (SMC) and progression of AAA.

Methods

Initially, we established angiotensin II (Ang II)-induced AAA mouse models and Ang II-treated vascular SMC model. RT-qPCR and Western blot analysis were adopted to determine expression of GAS5 and zeste homolog 2 (EZH2). After ectopic expression and depletion experiments in Ang II-treated mice and vascular SMCs, cell apoptosis was detected in SMCs using flow cytometry and in mice using TUNEL staining. The binding of GAS5 and EZH2 was evaluated using RNA binding protein immunoprecipitation (RIP) and Co-IP assays.

Results

Increased GAS5 and RIG-I but decreased EZH2 were found in aortic tissues of AAA mice. EZH2 overexpression inhibited AAA formation and suppressed SMC apoptosis. Functionally, EZH2 blocked the RIG-I signaling pathway and consequently inhibited SMC apoptosis. GAS5 regulated EZH2 transcription in a negative manner in SMCs. Knockdown of GAS5 attenuated SMC apoptosis, which was reversed by EZH2 inhibition or RIG-I overexpression.

Conclusions

The current study demonstrated that GAS5 induced SMC apoptosis and subsequent AAA onset by activating EZH2-mediated RIG-I signaling pathway, highlighting GAS5 as a novel biomarker for AAA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03023-w.

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.

Emerging Roles of LncRNAs in the EZH2-regulated Oncogenic Network

Cancer is a life-threatening disease, but cancer therapies based on epigenetic mechanisms have made great progress. Enhancer of zeste homolog 2 (EZH2) is the key catalytic component of Polycomb repressive complex 2 (PRC2) that mediates the tri-methylation of lysine 27 on histone 3 (H3K27me3), a well-recognized marker of transcriptional repression. Mounting evidence indicates that EZH2 is elevated in various cancers and associates with poor prognosis. In addition, many studies revealed that EZH2 is also involved in transcriptional repression dependent or independent of PRC2. Meanwhile, long non-coding RNAs (lncRNAs) have been reported to regulate numerous and diverse signaling pathways in oncogenesis. In this review, we firstly discuss functional interactions between EZH2 and lncRNAs that determine PRC2-dependent and -independent roles of EZH2. Secondly, we summarize the lncRNAs regulating EZH2 expression at transcription, post-transcription and post-translation levels. Thirdly, we review several oncogenic pathways cooperatively regulated by lncRNAs and EZH2, including the Wnt/β-catenin and p53 pathways. In conclusion, lncRNAs play a key role in the EZH2-regulated oncogenic network with many fertile directions to be explored.

Regulation of Mitochondrial Function by Noncoding RNAs in Heart Failure and Its Application in Diagnosis and Treatment

ABSTRACT

Heart failure (HF) is the terminal stage of multiple cardiovascular diseases. However, the pathogenesis of HF remains unclear and prompt; appropriate diagnosis and treatment of HF are crucial. Cardiomyocytes isolated from HF subjects frequently present mitochondrial impairment and dysfunction. Many studies have suggested that the regulation by noncoding RNAs (ncRNAs) of mitochondria can affect the occurrence and progression of HF. The regulation by ncRNAs of myocardial mitochondria during HF and the recent applications of ncRNAs in the diagnosis and treatment of HF are summarized in this review that is intended to gain keen insights into the mechanisms of HF and more effective treatments.

Long Non-Coding RNAs as Potential Diagnostic and Prognostic Biomarkers in Breast Cancer: Progress and Prospects

Breast cancer is the most common malignancy among women worldwide, excluding non-melanoma skin cancer. It is now well understood that breast cancer is a heterogeneous entity that exhibits distinctive histological and biological features, treatment responses and prognostic patterns. Therefore, the identification of novel ideal diagnostic and prognostic biomarkers is of utmost importance. Long non-coding RNAs (lncRNAs) are commonly defined as transcripts longer than 200 nucleotides that lack coding potential. Extensive research has shown that lncRNAs are involved in multiple human cancers, including breast cancer. LncRNAs with dysregulated expression can act as oncogenes or tumor-suppressor genes to regulate malignant transformation processes, such as proliferation, invasion, migration and drug resistance. Intriguingly, the expression profiles of lncRNAs tend to be highly cell-type-specific, tissue-specific, disease-specific or developmental stage-specific, which makes them suitable biomarkers for breast cancer diagnosis and prognosis.

Role of Long Non-coding RNAs on Bladder Cancer

Bladder cancer (BC) is the most common malignant tumor in the urinary system, and its early diagnosis is conducive to improving clinical prognosis and prolonging overall survival time. However, few biomarkers with high sensitivity and specificity are used as diagnostic markers for BC. Multiple long non-coding RNAs (lncRNAs) are abnormally expressed in BC, and play key roles in tumorigenesis, progression and prognosis of BC. In this review, we summarize the expression, function, molecular mechanisms and the clinical significance of lncRNAs on bladder cancer. There are more than 100 dysregulated lncRNAs in BC, which are involved in the regulation of proliferation, cell cycle, apoptosis, migration, invasion, metabolism and drug resistance of BC. Meanwhile, the molecular mechanisms of lncRNAs in BC was explored, including lncRNAs interacting with DNA, RNA and proteins. Additionally, the abnormal expression of thirty-six lncRNAs is closely associated with multiple clinical characteristics of BC, including tumor size, metastasis, invasion, and drug sensitivity or resistance of BC. Furthermore, we summarize some potential diagnostic and prognostic biomarkers of lncRNA for BC. This review provides promising novel biomarkers in early diagnosis, prognosis and monitoring of BC based on lncRNAs.

miR-4293 upregulates lncRNA WFDC21P by suppressing mRNA-decapping enzyme 2 to promote lung carcinoma proliferation

Non-coding RNAs (ncRNAs) involve in diverse biological processes by post-transcriptional regulation of gene expression. Emerging evidence shows that miRNA-4293 plays a significant role in the development of non-small cell lung cancer. However, the oncogenic functions of miR-4293 have not been studied. Our results demonstrated that miR-4293 expression is markedly enhanced in lung carcinoma tissue and cells. Moreover, miR-4293 promotes tumor cell proliferation and metastasis but suppresses apoptosis. Mechanistic investigations identified mRNA-decapping enzyme 2 (DCP2) as a target of miR-4293 and its expression is suppressed by miR-4293. DCP2 can directly or indirectly bind to WFDC21P and downregulates its expression. Consequently, miR-4293 can further promote WFDC21P expression by regulating DCP2. With a positive correlation to miR-4293 expression, WFDC21P also plays an oncogenic role in lung carcinoma. Furthermore, knockdown of WFDC21P results in functional attenuation of miR-4293 on tumor promotion. In vivo xenograft growth is also promoted by both miR-4293 and WFDC21P. Overall, our results establish oncogenic roles for both miR-4293 and WFDC21P and demonstrate that interactions between miRNAs and lncRNAs through DCP2 are important in the regulation of carcinoma pathogenesis. These results provided a valuable theoretical basis for the discovery of lung carcinoma therapeutic targets and diagnostic markers based on miR-4293 and WFDC21P.

Long non-coding RNA PCAT6 regulates bladder cancer progression via the microRNA-143-3p/PDIA6 axis

Although long non-coding (lnc)RNAs have been reported to be involved in the pathological development of bladder cancer, the functions of lncRNA prostate cancer-associated transcript 6 (PCAT6) and its underlying mechanism of action in bladder cancer remain unknown. The present study aimed to investigate the effect of PCAT6 in bladder cancer progression and explore its potential application as a novel treatment target. The expression of PCAT6 and miR-143-3p in bladder cancer tissues, adjacent normal tissues and cell lines was measured using reverse transcription-quantitative PCR. Fluorescence in situ hybridization assay was used to detect the subcellular localization of PCAT6. MTT, EdU, Transwell and wound healing assays were conducted to assess the biological function of PCAT6 on cell proliferation, migration and invasion. Putative binding sites between miR-143-3p and PCAT6 or PDIA6 were predicted using starBase, Lncbase and TargetScan analyzes. Dual-luciferase reporter assay was also used to confirm the potential binding between PCAT6 and miR-143-3p. RNA immunoprecipitation assay was performed to verify the possible interaction between PCAT6 and miR-143-3p. Western blotting was used to measure the expression of PDIA6. The results demonstrated that the expression levels of PCAT6 were upregulated in bladder cancer tissues relative to those in adjacent normal bladder tissues. Knockdown of PCAT6 served a role in suppressing the proliferation, migration and invasion of T24T and EJ bladder cancer cells. PCAT6 knockdown contributed to a reduction of PDIA6 expression at the mRNA and protein levels compared with that in negative control-transfected cells, whilst the miR-143-3p inhibitor partially mitigated this reduction effect. In addition, rescue experiments revealed that the miR-143-3p inhibitors reversed the effects of PCAT6 silencing on the malignant phenotypes of bladder cancer. Collectively, the results of the present study demonstrated that PCAT6 may serve an oncogenic role in bladder cancer via the miR-143-3p/PDIA6 axis. These results may provide a potential therapeutic target for the treatment of bladder cancer.

Long noncoding RNA network: Novel insight into hepatocellular carcinoma metastasis (Review)

Hepatocellular carcinoma (HCC) is one of the most common, aggressive malignancies with poor prognosis and high mortality. Although great progress has been made in recent decades, overall survival of HCC patients remains unsatisfactory due to high recurrence and metastasis. Accordingly, understanding and clarifying the underlying molecular mechanisms of metastasis has become increasingly important. Recently, accumulated reports have supported that long noncoding RNAs (lncRNAs) are dysregulated in HCC and are involved in various pivotal biological processes, including metastasis. The aim of this review was to investigate the dysregulation of lncRNAs in HCC and their function as oncogenes or tumour suppressors. Furthermore, reciprocal regulatory networks between lncRNAs and various molecules that were identified in HCC metastasis, including regulating epithelial-mesenchymal transition (EMT), controlling metastasis-associated genes, and regulating tumour angiogenesis were examined. Numerous reports and information on lncRNAs may help identify lncRNAs that are potential novel diagnostic markers, prognostic markers and therapeutic targets.

Long Noncoding RNA SNHG1 Activates Autophagy and Promotes Cell Invasion in Bladder Cancer

LncRNAs play important roles in bladder cancer. However, only a few studies report on the correlation between lncRNAs expression and autophagy in bladder cancer. This study aimed to explore the effect of lncRNA on autophagy in bladder cancer. The findings showed high expression of SNHG1 in the bladder cancer cells and tumor tissues. The high expression of SNHG1 was positively correlated with bladder cancer cell invasion, proliferation, and autophagy. This finding implies that SNHG1 promotes bladder cancer cell invasion and proliferation via autophagy. Further analysis of the mechanism of action of SNHG1 showed that it functions as a sponge of miRNA-493 in bladder cancer. miRNA-493 binds on the 3’ -UTR of ATG14 mRNA thus affecting ATG14 protein expression, which is implicated in autophagy. These findings are supported by previous preclinical studies using multiple Bca cell lines and TCGA, which demonstrate that SNHG1 plays an oncogenic role by acting as a sponge of miR-493-5p or as its ceRNA. Upregulation of SNHG1 promotes proliferation, invasion, and autophagy of bladder cancer cells through the miR-493-5p/ATG14/autophagy pathway. Therefore, SNHG1 may act as a potential therapeutic target for the treatment of bladder cancer.

Long Noncoding RNA KCNMB2-AS1 Promotes SMAD5 by Targeting miR-3194-3p to Induce Bladder Cancer Progression

Purpose

Bladder cancer is a common malignant tumor of the urinary system, with the fourth-highest incidence of male malignant tumors in Europe and the United States. So far, the mechanism of bladder cancer progression and metastasis has not been clarified. The aim of our study was to validate the way of long noncoding RNA (lncRNA) KCNMB2-AS1 on the metabolism and growth of bladder cancer cells by miR-3194-3p/SMAD5.

Patients and Methods

The Gene Expression was analyzed by qRT-PCR in bladder cancer tissues and cell lines, with the highly expressed KCNMB2-AS1 screened out. Cell proliferation was detected by Edu staining and clone formation assay, cell migration, and invasion by wound healing and transwell assays. Cell stemness was determined by assessing sphere-forming ability and stemness marker. Correlation between miRNA and lncRNA/gene was verified by dual‐luciferase assay and RIP, and the effect of KCNMB2-AS1 on bladder cancer growth by nude mice tumor formation experiment.

Results

Here, we revealed the increased level of KCNMB2-AS1 in bladder cancer for the first time. Knockdown of KCNMB2-AS1 in vitro prevented the ability of proliferation, metastasis, and stemness of cancer cells. In vivo, the silencing of KCNMB2-AS1 also prevented tumor growth in vivo. Next, we revealed that KCNMB2-AS1 could interact with miR-3194-3p and uncovered that SAMD5 was a downstream target of miR-3194-3p.

Conclusion

In conclusion, KCNMB2-AS1 mediated the bladder cancer cells progress by regulating the miR-3194-3p/SAMD5 signal pathway, which would provide a new target for bladder cancer research.

Long Noncoding RNA Small Nucleolar Host Gene: A Potential Therapeutic Target in Urological Cancers

The incidence of urological cancer has been gradually increasing in the last few decades. However, current diagnostic tools and treatment strategies continue to have limitations. Substantial evidence shows that long noncoding RNAs (lncRNAs) play essential roles in carcinogenesis and the progression, treatment response and prognosis of multiple human cancers, including urological cancers, gastrointestinal tumours, reproductive cancers and respiratory neoplasms. LncRNA small nucleolar RNA host genes (SNHGs), a subgroup of lncRNAs, have been found to be dysregulated in tumour cell biology. In this review, we summarize the impacts of lncRNA SNHGs in urological malignancies and the underlying mechanisms.

Malat-1 expression in bladder carcinoma tissues and its clinical significance

OBJECTIVE

To investigate the expression of metastasis-associated lung adenocarcinoma transcript 1 (Malat-1) in bladder carcinoma and its relationship with clinicopathological characteristics and prognosis.

METHODS

Specimens were collected from 90 patients with bladder carcinoma who underwent urological surgery in our hospital. Twenty patients diagnosed with benign prostatic hyperplasia were selected as the negative control. The expression of Malat-1 was detected by real-time reverse transcription PCR, and its relationship with clinicopathological factors and prognosis was analyzed.

RESULTS

The expression of Malat-1 in bladder carcinoma tissues (2.55±0.31) was higher than that in adjacent tissues (1.62±0.42) and normal bladder mucosa tissues (0.84±0.06); the differences were statistically significant (t=13.647 and 27.302, both P<0.001). The high expression rate of Malat-1 in bladder carcinoma tissues (86.67%) was significantly higher than that in adjacent tissues (22.22%) and normal bladder mucosa tissues (5.00%; P=0.000 and 0.000). The high expression rate of Malat-1 was correlated with age, tumor staging, degree of differentiation and lymph node metastasis (P=0.018, 0.000, 0.000, and 0.000). The median survival time and the 1-year, 3-year and 5-year survival rates of patients with high Malat-1 expression were lower than those with low expression of Malat-1 (P=0.006, 0.011, 0.000 and 0.002). High expression of Malat-1 is an independent risk factor for poor overall survival (OS) in bladder cancer patients.

CONCLUSION

Overexpression of Malat-1 in bladder carcinoma tissues is associated with malignant biological characteristics and poor prognosis of patients.

The interplay between HIF-1α and long noncoding GAS5 regulates the JAK1/STAT3 signalling pathway in hypoxia-induced injury in myocardial cells

Background

Long non-coding RNA (lncRNA) GAS5 is associated with hypoxia-induced diseases whereas hypoxia-inducible factor-1α (HIF-1α) plays an important role in hypoxic injury of cells. The current study explores the regulatory functions of GAS5/HIF-1α which co-play in anoxic injury among rat cardiomyocytes H9C2 cells.

Methods

Hypoxia in vitro model was established through anoxic incubation while normal culture of H9C2 cells was considered as control. The expression levels of GAS5 and HIF-1α were quantified through RT-qPCR. CCK-8 was applied to determine cell viability. Cell apoptosis rate was calculated using flow cytometry whereas inflammatory cytokines were detected using ELISA method. The impact of downregulating GAS5 or HIF-1α or both upon hypoxic cells was assessed on the basis of changes in cell viability, apoptosis, and inflammatory response. The activity of JAK1/STAT3 signaling was evaluated through RT-qPCR for mRNA expression. AG490 was introduced to inactivate JAK1/STAT3 pathway and to unveil the impact of JAK1/STAT3 signaling on GAS5/HIF-1α and cell viability, apoptosis and inflammation in hypoxic cells.

Results

The results infer that hypoxia suppressed cell viability, promoted inflammation and apoptosis among H9C2 cells. GAS5 or HIF-1α recorded higher expression in hypoxia-induced cells whereas the cell viability got restored with reduction in inflammation and apoptosis. The downregulation of HIF-1α enhanced the protective effect of knocking down GAS5 in hypoxia H9C2 cells. JAK1/STAT3 signaling pathway got activated in hypoxic cells and was regulated by GAS5 and HIF-1α. The inhibition of signaling pathway increased the cell viability but it decreased both inflammation and apoptosis.

Conclusions

GAS5 and HIF-1α could regulate hypoxic injury in H9C2 cells through JAK1/STAT3 signaling pathway. This scenario suggests that the inhibitors of GAS5 and HIF-1α may synergize with AG-490 to protect myocardial cells from hypoxic injury.

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

Simple Summary

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

Abstract

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

Long Noncoding RNAs as Innovative Urinary Diagnostic Biomarkers

The characterization of circulating tumor cells (CTCs) is now widely studied as a promising source of cancer-derived biomarkers because of their role in tumor formation and progression. However, CTCs analysis presents some limitations and no standardized method for CTCs isolation from urine has been defined so far. In fact, besides blood, urine represents an ideal source of noninvasive biomarkers, especially for the early detection of genitourinary tumors. Besides CTCs, long noncoding RNAs (lncRNAs) have also been proposed as potential noninvasive biomarkers, and the evaluation of the diagnostic accuracy of urinary lncRNAs has dramatically increased over the last years, with many studies being published. Therefore, this review provides an update on the clinical utility of urinary lncRNAs as novel biomarkers for the diagnosis of bladder and prostate cancers.

LINC00649 promotes bladder cancer malignant progression by regulating the miR‑15a‑5p/HMGA1 axis

The aim of the present study was to explore the effects of LINC00649 on the proliferation, migration and invasion of bladder cancer (BC) and identify possible mechanisms. Through TCGA database analysis of LINC00649 expression in bladder cancer and the association of LINC00649 with the BC patient prognosis, RT‑qPCR was employed for detecting LINC00649 expression in 60 clinical tissue specimens and cell lines of bladder cancer. The lentivirus stable transfection or small interfering RNA was used to increase or decrease the LINC00649 expression level in T24 and UM‑UC‑3 cells. CCK8 and clone formation assay were utilized to observe the effects of LINC00649 on the proliferation and colony formation of BC cells. Transwell experiment was performed to detect the effects of LINC00649 on the migration and invasion of bladder cancer. Bioinformatics database was used to identify the possible downstream targets of LINC00649 while RT‑qPCR, western blot analysis and dual luciferase reporter gene experiments were carried out to verify the possible molecular mechanism. The TCGA database analysis revealed a significantly high expression of LINC00649 in bladder cancer and an association of LINC00649 expression with overall survival rate of BC patients. As shown by RT‑qPCR detection, LINC00649 expression was notably upregulated in BC tissues and BC cell lines. In addition, statistical analyses unveiled that highly expressed LINC00649 was clearly associated with poor overall survival of bladder cancer. Based on the in vitro cell experiment, upregulated LINC00649 considerately enhanced the proliferation, migration and invasion of BC cells, as opposed to those in T24 and UM‑UC‑3 cells by suppressing LINC00649. Mechanically, LINC00649 may promote the malignant progression of bladder cancer by regulating miR‑15a‑5p to promote the HMGA1 expression axis. Overall, LINC00649 upregulates HMGA1 expression by binding to miR‑15a‑5p to enhance the proliferation, migration and invasion of BC cells. Thus, LINC00649 is a potential biomarker and therapeutic target for bladder cancer.

LINC01106 post-transcriptionally regulates ELK3 and HOXD8 to promote bladder cancer progression

Bladder cancer (BCa) is a kind of common urogenital malignancy worldwide. Emerging evidence indicated that long noncoding RNAs (lncRNAs) play critical roles in the progression of BCa. In this study, we discovered a novel lncRNA LINC01116 whose expression increased with stages in BCa patients and closely related to the survival rate of BCa patients. However, the molecular mechanism dictating the role of LINC01116 in BCa has not been well elucidated so far. In our study, we detected that the expression of LINC01116 was boosted in BCa cells. Moreover, the results of a series of functional assays showed that LINC01116 knockdown suppressed the proliferation, migration, and invasion of BCa cells. Thereafter, GEPIA indicated the closest correlation of LINC01116 with two protein-coding genes, ELK3 and HOXD8. Interestingly, LINC01116 was mainly a cytoplasmic lncRNA in BCa cells, and it could modulate ELK3 and HOXD8 at post-transcriptional level. Mechanically, LINC01116 increased the expression of ELK3 by adsorbing miR-3612, and also stabilized HOXD8 mRNA by binding with DKC1. Rescue experiments further demonstrated that the restraining influence of LINC01116 knockdown on the progression of BCa, was partly rescued by ELK3 promotion, but absolutely reversed by the co-enhancement of ELK3 and HOXD8. More intriguingly, HOXD8 acted as a transcription factor to activate LINC01116 in BCa. In conclusion, HOXD8-enhanced LINC01116 contributes to the progression of BCa via targeting ELK3 and HOXD8, which might provide new targets for treating patients with BCa.

The roles of long noncoding RNAs in myocardial pathophysiology

Long noncoding RNAs (lncRNAs), more than 200 nt in length, are functional molecules found in various species. These lncRNAs play a vital role in cell proliferation, differentiation, and degeneration and are also involved in pathophysiological processes of cancer and neurodegenerative, autoimmune, and cardiovascular diseases (CVDs). In recent years, emerging challenges for intervention studies on ischemic heart diseases have received much attention. LncRNAs have a key function in the alleviation of myocardial infarction (MI) injury and myocardial ischemia–reperfusion injury. During cardiac hypertrophy (CH) and fibrosis, cardiac cells undergo structural changes and become dysfunctional due to the effects of neurohormonal factors. LncRNAs may serve as important therapeutic targets that promote cardiac remodeling and then retard the development of heart failure (HF). In addition, studies on the roles and mechanisms of action of lncRNAs participating in cardiac pathophysiology via other factors have become the focus of research worldwide. Here, we review the current knowledge on various lncRNAs and their functions in cardiac biology, particularly concentrating on ischemic heart disease, CH, and cardiac fibrosis. We next discuss the predictive value of lncRNAs as diagnostic biomarkers of CVDs.

The long non-coding RNA SNHG1 promotes bladder cancer progression by interacting with miR-143-3p and EZH2

The long non-coding RNA (lncRNA) SNHG1 has been shown to be implicated in the progression of multiple human carcinomas. Nevertheless, the biological functions and potential mechanism of SNHG1 in bladder cancer (BC) are uncharacterized. In the present study, SNHG1 was found to be substantially up-regulated in BC tissues and cells and was intimately correlated with the TNM stage, lymphatic invasion, metastasis and recurrence-free survival in BC patients. Down-regulation of SNHG1 dramatically attenuated the proliferation, migration and invasion of BC cells, whereas the ectopic overexpression of SNHG1 had the opposite effects in vitro. The in vivo experimental results also indicated that SNHG1 down-regulation hampered the tumour growth and metastasis of BC cells. Mechanistic investigations revealed that SNHG1 enhances HK2 expression by serving as an endogenous sponge to regulate miR-143-3p in the cytoplasm of BC cells. In the nucleus, SNHG1 could interact with EZH2 and regulate the histone methylation of the CDH1 promoter, altering the biological behaviours of BC cells. Overall, these findings elucidate an oncologic role of SNHG1 in BC and provide a new therapeutic strategy against BC.

Determination of long non-coding RNAs associated with EZH2 in neuroblastoma by RIP-seq, RNA-seq and ChIP-seq

Neuroblastoma (NB) is the most common type of extracranial solid tumor found in children. Despite several treatment options, patients with advanced stage disease have a poor prognosis. Previous studies have reported that enhancer of zeste homolog 2 (EZH2) and long non-coding RNAs (lncRNAs) have abnormal expression levels in NB and participate in tumorigenesis and NB development. However, the association between EZH2 and lncRNAs remain unclear. In the present study, RNA immunoprecipitation-sequencing (RIP-seq) was used to analyze the lncRNAs binding to EZH2. Following EZH2 knockdown via short hairpin RNA, RNA-seq was performed in shEZH2 and control groups in SH-SY5Y cells. Chromatin IP (ChIP)-seq was used to determine the genes that may be regulated by EZH2. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to identify the signaling pathways involved in NB. The results from RIP-seq identified 94 lncRNAs, including SNHG7, SNHG22, KTN-AS1 and Linc00843. Furthermore, results from RNA-seq demonstrated that, following EZH2 knockdown, 448 genes were up- and 571 genes were downregulated, with 32 lncRNAs up- and 35 downregulated and differentially expressed compared with control groups. Certain lncRNAs, including MALAT1, H19, Linc01021 and SNHG5, were differentially expressed in EZH2-knockdown group compared with the control group. ChIP-seq identified EZH2 located in the promoter region of 138 lncRNAs including CASC16, CASC15, LINC00694 and TBX5-AS1. In summary, the present study demonstrated that certain lncRNAs directly bound EZH2 and regulated EZH2 expression levels. A number of these lncRNAs that are associated with EZH2 may participate in NB tumorigenesis.

Long non‑coding RNA growth arrest‑specific 5 (GAS5) acts as a tumor suppressor by promoting autophagy in breast cancer

Growth arrest-specific 5 (GAS5) is a known tumor suppressor which negatively regulates cell survival and malignancy in several cancer cell types. The present study aimed to establish the correlation between GAS5 and unc-51 like autophagy activating kinase (ULK)1/2, two key regulators of autophagy initiation in breast cancer (BC). To address this, expression levels of these genes were quantitively analyzed in BC clinical samples by performing reverse transcription-quantitative PCR. GAS5 was downregulated in BC clinical samples compared with adjacent samples and was positively correlated with ULK1/2. Detection methods including cell cycle analysis, annexin V-FITC/PI double staining and flow cytometry analysis, Transwell cell invasion assay, transfection and western blotting were used for BC cells. In MCF-7 cells, it was also observed that overexpression of GAS5 upregulated ULK1/2 protein levels without disturbing other autophagy initiation-associated proteins and inhibited cell proliferation, invasion and tumor formation. These effects were reversed by blocking autophagy with 3-methyladenine (3-MA). These results demonstrated that the suppressive effects of overexpressed GAS5 were mediated via autophagy induction, at least in part. Overexpression of GAS5 induced chemoresistance to cisplatin, which was not reversed by 3-MA-mediated inhibition of autophagy, indicating that GAS5 promotes chemosensitivity in an autophagy-independent manner. Collectively, these results indicated that GAS5 contributes to the pathogenesis of BC potentially by promoting autophagy. However, the mechanism by which GAS5 functions as a tumor suppressor in an autophagy-independent manner remains unknown.

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.

CASC9 Facilitates Cell Proliferation in Bladder Cancer by Regulating CBX2 Expression

BACKGROUND

As the seventh most common urologic carcinoma worldwide, approximately 430,000 patients are diagnosed with bladder cancer (BC) every year. Increasing evidence indicates that long noncoding RNAs (lncRNAs) play crucial roles in the progression of BC.

OBJECTIVES

This study is aimed to explore the function and mechanism of CASC9 in BC.

METHODS

Bioinformatics analysis and experiments including RT-qPCR, luciferase reporter, Cell Counting Kit-8 assay, Western blot, RNA immunoprecipitation assay, and TUNEL staining were applied to explore the function and mechanism of CASC9 in BC tissues and cell lines.

RESULTS

Our study demonstrated that CASC9 was upregulated in BC tissues and cell lines. Moreover, we found that CASC9 knockdown notably decreased proliferation while increased apoptotic rate in BC cells. Mechanistically, bioinformatics prediction and following experiments indicated that CASC9 worked as a competing endogenous RNA (ceRNA) of CBX2 through sponging miR-497-5p. Meanwhile, we recognized that CASC9 and miR-497-5p negatively regulated each other in a mutual way. Furthermore, we found that miR-497-5p shared binding site with CBX2. In addition, miR-497-5p could negatively regulated CBX2, while CASC9 could positively regulated CBX2. Rescue assays reveled that CBX2 overexpression could reversed the reduction of cell proliferation or the enhancement of cell apoptosis induced by CASC9 suppression.

CONCLUSIONS

Our study manifests the first evidence that CASC9 serves as an oncogene in BC and accelerates cell proliferation by modulating miR-497-5p/CBX2 axis. The present study may provide a cogitable target for BC therapy.

Long non-coding RNA GAS5, by up-regulating PRC2 and targeting the promoter methylation of miR-424, suppresses multiple malignant phenotypes of glioma

PURPOSE

Malignant gliomas remain significant challenges in clinic and pose dismal prognosis on patients. In this study, we focused on growth arrest-specific 5 (GAS5), a tumor suppressive long non-coding RNA in glioma, explored its crosstalk with miR-424, and examined their biological functions in glioma.

METHODS

Expressions of GAS5 and miR-424 were measured using qRT-PCR. The regulation of GAS5 on miR-424 expression was examined in GAS5-overexpressing glioma cells by combining methylation-specific PCR, western blotting, and RNA immunoprecipitation. Functional significance of GAS5 and miR-424 on in vitro cell proliferation, apoptosis, migration, invasion, and in vivo tumor growth was examined using colony formation, flow cytometry, wound healing, transwell assay, and the xenograft model, respectively. The potential targeting of AKT3 by miR-424 was investigated using luciferase reporter assay.

RESULTS

GAS5 and miR-424 were significantly down-regulated in glioma cells. GAS5 directly interacted with enhancer of zeste homolog 2 (EZH2), stimulated the formation of polycomb repressive complex 2 (PRC2), reduced the levels of DNA methyltransferases (Dnmts), alleviated promoter methylation of miR-424, and promoted miR-424 expression. Functionally, GAS5, by up-regulating miR-424, inhibited cell proliferation, migration, and invasion, while increased apoptosis of glioma cells in vitro, and suppressed xenograft growth in vivo. miR-424 directly inhibited AKT3 and altered the expressions of AKT3 targets, cyclinD1, c-Myc, Bax, and Bcl-2, which might contribute to its tumor suppressive activities.

CONCLUSIONS

GAS5, by inhibiting methylation and boosting expression of miR-424, inhibits AKT3 signaling and suppresses multiple malignant phenotypes. Therefore, stimulating GAS5/miR-424 signaling may benefit the treatment of glioma.

Non-coding RNA in bladder cancer

Bladder cancer is the tenth most common cancer worldwide and has been associated with high mortality and morbidity. Although the treatment of bladder cancer is based on well-defined tumor classifications and gradings, patients still experience different clinical response. The heterogeneity of this disease calls for substantial research with more in-depth molecular characterization, with the hope of identifying new diagnostic and treatment options. In recent years, non-coding RNAs (ncRNAs), particularly, microRNAs (miRNAs), long non-coding RNA (lncRNAs), and circular RNAs (circRNAs) were found to be associated with bladder cancer occurrence and development. This review highlights the recent findings concerning ncRNAs and their relevance to the pathogenesis of bladder cancer. This may provide a foundation for developing highly specific diagnostic tools and more robust therapeutic strategies in the future.

Comprehensive analysis of long non‑coding RNA using an associated competitive endogenous RNA network in Wilms tumor

Wilms tumor (WT) is the most common malignant renal neoplasm in children; however, the underlying molecular mechanisms are not well understood. According to the competing endogenous RNA (ceRNA) theory, long non-coding RNAs (lncRNAs) can regulate the expression of target genes by adsorbing microRNAs (miRNAs/miRs). However, the role of lncRNAs in WT has not been fully elucidated. The aim of the present study was to construct a ceRNA network to identify the potential lncRNAs involved in WT. The expression profiles of lncRNAs, miRNAs and mRNAs in 120 WT and six normal tissues were obtained from the Therapeutically Applicable Research to Generate Effective Treatments database. A total of 442 lncRNAs, 214 miRNAs and 4,912 mRNAs were identified as differentially expressed in WT and were enriched in 472 Gene Ontology terms (355 biological processes, 89 cellular components and 29 molecular functions) and 18 Kyoto Encyclopedia of Genes and Genomes pathways. A lncRNA-miRNA-mRNA ceRNA network of WT consisting of with 32 lncRNAs, 14 miRNAs and 158 mRNAs was constructed, based on the bioinformatics analysis of the miR target prediction database and the miRNAcode, miRTarBase and TargetScan databases. Subsequently, three lncRNAs, three miRNAs and 17 mRNAs, which had a significant effect on the overall survival rate of patients with WT, were identified based on the survival analysis. The three lncRNAs were also differentially expressed in the late and early stages of WT and were validated using the GSE66405 dataset obtained from the Gene Expression Omnibus database. In conclusion, the present study generated a specific lncRNA-related ceRNA network of WT, which may provide a novel perspective on the molecular mechanisms underlying the progression and prognosis of the disease.

LncRNA HAND2-AS1 represses cervical cancer progression by interaction with transcription factor E2F4 at the promoter of C16orf74

Cervical cancer is one of the major malignancies, the pathophysiology and progression of which remain to be scarcely understood. Long non-coding RNAs (lncRNAs) have been previously implicated in the progression of cervical cancer. Here, the purpose of this study was to identify whether lncRNA heart- and neural crest derivative-expressed 2-antisense RNA 1 (HAND2-AS1) affect the development of cervical cancer through regulation of chromosome 16 open reading frame 74 (C16orf74) by mediating a transcription factor E2F4. RT-qPCR was performed to determine the expression of HAND2-AS1 in cervical cancer cells. Then, cervical cancer cells were treated with HAND2-AS1 or si-E2F4 RNA, or C16orf74, after which the proliferation, colony formation, migration and invasion were detected. Moreover, the binding between HAND2-AS1 and E2F4 or between E2F4 and C16orf74 was explored. Finally, the tumorigenesis of cervical cancer cells was measured in nude mice with altered HAND2-AS1/E2F4/C16orf74 expression. HAND2-AS1 exhibited poor expression in cervical cancer, and HAND2-AS1 overexpression suppressed the proliferation, colony formation, migration and invasion of cervical cancer cells. In addition, HAND2-AS1 was found to recruit transcription factor E2F4 to C16orf74 promoter region and down-regulate C16orf74 expression. Lastly, HAND2-AS1/E2F4/C16orf74 modulated the tumorigenesis of cervical cancer in nude mice. In conclusion, this study provided evidence on the inhibitory effect of HAND2-AS1 on the development of cervical cancer through the suppression of C16orf74 expression by recruiting transcription factor E2F4. This study highlights the potential of lncRNA HAND2-AS1 as a target in the treatment of cervical cancer.

LncRNA-GAS5 regulates PDCD4 expression and mediates myocardial infarction-induced cardiomyocytes apoptosis via targeting MiR-21

The present study was designed to investigate whether and how lncRNA-GAS5 regulates cardiomyocyte apoptosis in MI. MI rat model was established by the left anterior descending (LAD) coronary artery ligation. MI model was further evaluated by biomarkers detection and TUNEL, HE and Masson staining. The roles of lncRNA-GAS5 on hypoxia/reoxygenation (H/R)-induced cardiomyocytes survival, cell cycle arrest, and apoptosis were examined by MTT and flow cytometry in rat heart-derived H9c2 cells. Western blot was used to determine the effect of GAS5 on the expression of apoptosis-associated proteins and PI3 K/AKT signaling pathway. The direct bindings of GAS5 to miR-21 and miR-21 to PDCD4 were measured by dual-luciferase reporter assay or RNA immunoprecipitation. Decreased expressions of GAS5 and PDCD4 as well as increased miR-21 level were observed in the hearts of MI-modeled rat, accompanying with morphologically myocardial cell injury, as well as collagen deposition and fibrosis, and elevated levels of cTnl, CK, CK-MB and LDH. In the cell model, the knockdown of GAS5 promoted cell survival, prevented cell cycle arrest and inhibited cell apoptosis while the overexpression of GAS5 showed the opposite effects. GAS5 was found to downregulate miR-21 and the effects of GAS5 were attenuated by miR-21 mimics. GAS5 positively regulated PDCD4 expression by functioning as a sponge of miR-21 in H/R model. Moreover, GAS5 stimulated PDCD4 and suppressed PI3 K/AKT signal pathway. LncRNA-GAS5 regulates PDCD4 expression to mediate MI-induced cardiomyocyte apoptosis via targeting miR-21, suggesting that GAS5 could be a therapeutic target for MI.

Long non-coding RNA GAS5 accelerates oxidative stress in melanoma cells by rescuing EZH2-mediated CDKN1C downregulation

Background

The significance of long non-coding RNAs (lncRNAs) in mediating oxidative stress of cancers has been implicated recently. This study proposed a potential therapeutic target lncRNA growth arrest-specific transcript 5 (GAS5) for melanoma, due to its crucial role in oxidative stress and apoptosis of melanoma cells by regulating the enhancer of zeste homolog 2 (EZH2)-mediated CDKN1C expression.

Methods

The lncRNA GAS5 expression pattern was examined in melanoma tissues and cells. The correlation of lncRNA GAS5, EZH2, and CDKN1C with survival rate of melanoma patients was analyzed. In melanoma cell lines, lncRNA GAS5 expression was overexpressed or knocked down to clarify its effects on cell viability, apoptosis, and oxidative stress. The interaction between lncRNA GAS5 and EZH2 was examined by RIP and RNA pull-down assays followed by verification of the target relationship between EZH2 and CDKN1C.

Results

High expression of EZH2 and poor expression of lncRNA GAS5 and CDKN1C was observed in melanoma tissues and found to be correlated with the reduction in survival expectancy of melanoma patients. Overexpression of lncRNA GAS5 or CDKN1C or EZH2 knockdown could inhibit cell viability but enhance melanoma cell apoptosis and oxidative stress. Importantly, lncRNA GAS5 attenuated EZH2 expression by recruiting E2F4 to the EZH2 promoter region and knockdown of EZH2 upregulated CDKN1C expression by inhibiting the H3K27me3.

Conclusion

The evidence provided by our study highlighted the involvement of lncRNA GAS5 in the translational suppression of EZH2 as well as the upregulation of CDKN1C, resulting in the promotion of melanoma cell apoptosis and oxidative stress.

Long noncoding RNA LINC00324 exerts protumorigenic effects on liver cancer stem cells by upregulating fas ligand via PU box binding protein

Hepatocellular carcinoma (HCC) represents a major cause of cancer death, but the molecular mechanism for its development has not yet been well characterized. Long noncoding RNAs (lncRNAs) are involved in a wide range of biological processes via their roles as oncogenes or tumor suppressor genes. The present study aimed to elucidate the role of LINC00324 in HCC through its interaction with Fas ligand (FasL). Initially, microarray-based gene expression profiling of HCC was employed to identify differentially expressed genes. Next, the expression of LINC00324 in HCC tissues and liver cancer stem cell (LCSC) lines was examined using RT-qPCR. Then, the interaction among LINC00324, PU box binding protein (PU.1) and FasL was identified with RIP, ChIP and dual-luciferase reporter gene assays. The effect of LINC00324 on viability, proliferation, migration, invasion, and apoptosis as well as the tumorigenesis of transfected cells was examined with gain- and loss-of-function experiments. LINC00324 and FasL were highly expressed in HCC. LINC00324 regulated FasL expression via interaction with PU.1. Silencing of LINC00324 or FasL suppressed expression of stemness-related genes, cell viability, proliferation, migration, invasion, self-renewal, and tumorigenesis, but enhanced cell apoptosis. Taken together, LINC00324 promotes the expression of FasL through the recruitment of PU.1, which ultimately maintains the biological properties of LCSCs, thus, highlighting LINC00324 as a promising therapeutic candidate for HCC.

LncRNA GAS5 enhanced the killing effect of NK cell on liver cancer through regulating miR-544/RUNX3

This study aimed to explore the role of lncRNA GAS5 in the regulation of the killing effect of NK cells on liver cancer. Compared with a control group, lncRNA GAS5, RUNX3, and NCR1 were down-regulated in NK cells of patients with liver cancer, whereas miR-544 expression was up-regulated in NK cells of patients with liver cancer. Activated NK cells had higher IFN-γ level. Knockdown of GAS5 in activated NK cells decreased IFN-γ secretion, NK cell cytotoxicity, the percentage of CD107a+ NK cells, and the apoptosis rate of HepG2 and Huh7 cells. We also proved the interaction of GAS5 and miR-544, and the negative regulation role of GAS5 on miR-544. GAS5 overexpression in activated NK cells increased RUNX3 expression, IFN-γ secretion, the NK cell cytotoxicity, the percentage of CD107a+ NK cells, and the apoptosis rate of HepG2 cells, while miR-544 mimic abolished the promotion effect of GAS5 overexpression. Finally, in vivo experiments indicated an inhibition effect of GAS5 in tumor growth. LncRNA GAS5 overexpression enhances the killing effect of NK cell on liver cancer through regulating miR-544/RUNX3.

Long non-coding RNA in bladder cancer

Bladder cancer (BC) is the ninth most common malignant disease and ranks fourteenth in cancer mortality worldwide. Moreover, among cancers, the incidence and mortality of BC in males increased to the 6th and 9th place, respectively. The overall survival (OS) declines dramatically as the cancer progresses, especially when urothelial cells transition from noninvasive to invasive. It is well known that epithelial cells can acquire invasive properties and a propensity to metastasize through the epithelial-to-mesenchymal transition (EMT) process in tumourigenesis and progression. However, the potential molecular mechanisms and key pathways are still unclear. As the sequencing technology advances, long non-coding RNAs (lncRNAs) have been proven to play an important role in regulating biological processes and cellular pathways. Here, we reviewed important lncRNAs, such as H19, UCA1 and MALAT1, that participate in the malignant phenotype of BC and regulate EMT signalling networks in the invasion-metastasis cascade during BC development. We further discuss MALAT1, PCAT-1 and SPRY4-IT1, and also urine and blood exosomal H19 and PTENP as potential noninvasive biomarkers. Moreover, antisense oligonucleotides (ASOs) and a double-stranded DNA plasmid (BC-819) have been designed for use in preclinical cancer models and clinical trials in patients. Therefore, the results of investigations have gradually prompted the utility of lncRNAs.

Long noncoding RNA growth arrest-specific transcript 5 alleviates renal fibrosis in diabetic nephropathy by downregulating matrix metalloproteinase 9 through recruitment of enhancer of zeste homolog 2

Diabetic nephropathy (DN) is a frequently occurred microvascular complication associated with type I and type II diabetes mellitus. The participation of long noncoding RNAs (lncRNAs) in diabetes-related microvascular complications has been reported extensively. We attempted to unveil the possible regulatory mechanism of lncRNA growth arrest-specific transcript 5 (GAS5) and matrix metalloproteinase 9 (MMP9), an important inflammatory protein, in the progression of DN. A rat DN model was induced by streptozocin (STZ). The low expression of GAS5 and high expression of MMP9 in DN rats with DN was then determined by RT-qPCR and western blot analysis, and lentivirus-mediated GAS5 overexpression was shown to ameliorate STZ-induced renal interstitial fibrosis (RIF) and inflammatory reaction in the kidney of DN rats. Moreover, MMP9 was found to be upregulated in STZ-induced DN, while MMP9 silencing induced by lentivirus expressing shRNA against MMP9 reduced RIF and suppressed inflammation in the kidney of DN rats. RIP, RNA pull-down, and ChIP assays demonstrated that GAS5 downregulated MMP9 via recruiting enhancer of zeste homolog 2 (EZH2) in the promoter region of MMP9. Overall, our study reveals that GAS5 downregulates MMP9 expression through recruiting EZH2 to MMP9 promoter region and alleviates the progression of renal fibrosis in DN rats, which sheds new light on the therapeutic potential of GAS5-targeted therapies in combating that disease.