Knockdown of long non-coding RNA HOTAIR increases miR-454-3p by targeting Stat3 and Atg12 to inhibit chondrosarcoma growth. Cell Death Dis. 2017;8:e2605. [PMID: 28182000 PMCID: PMC5386479 DOI: 10.1038/cddis.2017.31]

HOTAIR in cancer: diagnostic, prognostic, and therapeutic perspectives

The long non-coding RNA HOTAIR is overexpressed in many cancers and is associated with several cancer-promoting effects, including increased cell proliferation, migration and treatment resistance. HOTAIR levels correlate with tumor stage, lymph node metastasis and overall survival in patients with various types of cancer. This highlights the potential uses of HOTAIR, including early cancer detection, predicting patient outcome, identifying high-risk individuals and assisting in therapy selection and monitoring. The aim of this review is to provide a comprehensive summary of the research progress, molecular mechanisms and clinical significance of HOTAIR in various human cancers. In addition, the clinical applications of HOTAIR, such as targeted therapy, radiotherapy, chemotherapy and immunotherapy, are discussed, and relevant information on the potential future advances of HOTAIR in cancer research is provided.

MiR-454-3p regulates high glucose-induced mesothelial-mesenchymal transition and glycolysis in peritoneal mesothelial cells by targeting STAT3

BACKGROUND

The quality of life of patients receiving long-term peritoneal dialysis (PD) is significantly impacted by the onset of peritoneal fibrosis (PF), and one of the pathological changes is mesothelial-mesenchymal transition (MMT). In this study, we investigated the potential roles of miR-454-3p and signal transducer and activator of transcription 3 (STAT3) in the progression of peritoneal MMT and the underlying mechanisms.

METHODS

Peritoneums were collected to detect morphology via hematoxylin-eosin staining and differentially expressed miRNAs were detected via RT-qPCR. PD effluent-derived cell populations in the peritoneal cavity were isolated from the effluents of 20 PD patients to determine miR-454-3p, STAT3, and MMT markers via Western blotting and RT-qPCR. The relationship between miR-454-3p and STAT3 was examined via a dual-luciferase reporter assay. Western blotting and RT-qPCR were utilized to evaluate the expression of STAT3, MMT markers, and glycolytic enzymes. Immunofluorescence staining revealed the localization and expression of MMT markers and STAT3.

RESULTS

MiR-454-3p was downregulated in the peritoneums and PD effluent-derived cell populations of long-term PD patients. High glucose (HG) treatment promoted HMrSV5 cell MMT and glycolysis. MiR-454-3p overexpression alleviated HG-induced MMT and suppressed the expression of STAT3 and glycolytic enzymes. In contrast, the miR-454-3p inhibitor exacerbated HG-induced MMT and promoted the expression of glycolytic enzymes and STAT3. Moreover, STAT3 was the target of miR-454-3p.

CONCLUSIONS

This study demonstrated the protective role of miR-454-3p in HG-induced MMT and glycolysis in HMrSv5 cells, suggesting that miR-454-3p may prevent MMT by suppressing glycolytic enzymes via the STAT3/PFKFB3 pathway in the HG environment.

LncRNA-miRNA interactions prediction based on meta-path similarity and Gaussian kernel similarity

Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) are two typical types of non-coding RNAs that interact and play important regulatory roles in many animal organisms. Exploring the unknown interactions between lncRNAs and miRNAs contributes to a better understanding of their functional involvement. Currently, studying the interactions between lncRNAs and miRNAs heavily relies on laborious biological experiments. Therefore, it is necessary to design a computational method for predicting lncRNA-miRNA interactions. In this work, we propose a method called MPGK-LMI, which utilizes a graph attention network (GAT) to predict lncRNA-miRNA interactions in animals. First, we construct a meta-path similarity matrix based on known lncRNA-miRNA interaction information. Then, we use GAT to aggregate the constructed meta-path similarity matrix and the computed Gaussian kernel similarity matrix to update the feature matrix with neighbourhood information. Finally, a scoring module is used for prediction. By comparing with three state-of-the-art algorithms, MPGK-LMI achieves the best results in terms of performance, with AUC value of 0.9077, AUPR of 0.9327, ACC of 0.9080, F1-score of 0.9143 and precision of 0.8739. These results validate the effectiveness and reliability of MPGK-LMI. Additionally, we conduct detailed case studies to demonstrate the effectiveness and feasibility of our approach in practical applications. Through these empirical results, we gain deeper insights into the functional roles and mechanisms of lncRNA-miRNA interactions, providing significant breakthroughs and advancements in this field of research. In summary, our method not only outperforms others in terms of performance but also establishes its practicality and reliability in biological research through real-case analysis, offering strong support and guidance for future studies and applications.

LINC00665 aggravates the malignant phenotypes in chondrosarcoma cells through miR-665/FGF9 pathway

Long non-coding RNAs (lncRNAs) have been demonstrated to participate in a variety of physiological and pathological processes, including tumor initiation and development. Nevertheless, few of them have been investigated in chondrosarcoma. Here, we were intended to unveil the role of long intergenic non-protein coding RNA 665 (LINC00665) in chondrosarcoma. RT-qPCR was adopted for gene expression detection. The biological processes in chondrosarcoma cells were detected by CCK-8, EdU, TUNEL, Transwell and wound healing assays. The relationships between genes in chondrosarcoma cells were evaluated by a series of mechanism experiments including RIP, luciferase reporter assays and so on.LINC00665 expressed at a high level in chondrosarcoma cell lines. LINC00665 interference suppressed cell proliferation, migration and invasion in chondrosarcoma. Besides, LINC00665 interacted with microRNA-665 (miR-665), which was then verified to be down-regulated in chondrosarcoma cells. Additionally, LINC00665 and miR-665 were mutually inhibited by each other in chondrosarcoma cells. Importantly, LINC00665 stimulated fibroblast growth factor 9 (FGF9) expression in chondrosarcoma cells via sponging miR-665. Furthermore, FGF9 participated in the regulation of LINC00665-promoted chondrosarcoma development. CONCLUSION: LINC00665 facilitates chondrosarcoma progression via miR-665/FGF9 axis, which might indicate a new path for the treatment of chondrosarcoma.

Non-nucleoside inhibitors of DNMT1 and DNMT3 for targeted cancer therapy

DNA methylation can deactivate tumor suppressor genes thus causing cancers. Two DNA methylation inhibitors have been approved by the Food and Drug Administration (FDA) and have entered clinical use. However, these inhibitors are nucleoside analogues that can be incorporated into DNA or RNA and induce significant side effects. DNMT1 and DNMT3 are key enzymes involved in DNA methylation. In the acute myeloid leukemia model, a non-nucleoside DNMT1-specific inhibitor has shown lower toxicity and improved pharmacokinetics compared to traditional nucleoside drugs. DNMT3 is also implicated in certain specific cancers. Thus, developing non-nucleoside inhibitors for DNMT1 or DNMT3 can help in understanding their roles in carcinogenesis and provide targeted treatment options in certain cancers. Although no non-nucleoside inhibitors have yet entered clinical trials, in this review, we focus on DNMT1 or DNMT3 selective inhibitors. For DNMT1 selective inhibitors, we have compiled information on the repurposed drugs, derivative compounds and selective inhibitors identified through virtual screening. Additionally, we have outlined potential targets for DNMT1, including protein-protein complex, RNA mimics and aptamers. Compared to DNMT1, research on DNMT3-specific inhibitors has been less extensive. In this context, our exploration has identified a limited number of molecular inhibitors, and we have proposed specific long non-coding RNAs (lncRNAs) as potential contributors to the selective inhibition of DNMT3. This collective effort aims to offer valuable insights into the development of non-nucleoside inhibitors that selectively target DNMT1 or DNMT3.

Participation of Long Noncoding RNA FOXP4-AS1 in the Development and Progression of Endometrioid Carcinoma with Epigenetically Silencing DUSP5

Background: Long noncoding RNAs (lncRNAs), as emerging regulators of a wide variety of biological processes via diverse mechanisms, have been demonstrated to be of increasing importance in biology. Genome-wide association studies of tumor samples have identified several lncRNAs as either oncogenes or tumor suppressors in various types of cancers. In recent years, the importance of lncRNAs, especially in endometrioid cancer (EEC), has become increasingly well understood. The lncRNA Forkhead box P4 antisense RNA 1 (FOXP4-AS1) has been reported to fulfill roles in several types of cancers; however, the main biological function and associated underlying molecular mechanism of FOXP4-AS1 in EEC have yet to be fully elucidated. The present study therefore aimed to investigate how RNA FOXP4-AS1 may participate in the development and progression of endometrioid carcinoma tissues. Materials and Methods: In the present study, the expression level of FOXP4-AS1 was investigated in endometrioid carcinoma tissues and matching nearby normal endometrial tissues collected from patients receiving surgery at the hospital. A series of molecular biological assays were performed to investigate the effect of FOXP4-AS1 on cell proliferation, cell migration, and cell invasion. Results: An increased concentration of FOXP4-AS1 was identified in endometrioid carcinoma samples and cell lines compared with the corresponding controls, and this lncRNA was found to be positively correlated with advanced FIGO stages in patients with endometrial cancer. Furthermore, knocking down endogenous FOXP4-AS1 led to a significant reduction in the colony formation number and a significant inhibition of cell proliferation, cell migration, and cell invasion in endometrioid carcinoma cells. Moreover, dual-specificity phosphatase 5 (DUSP5), which is lowly expressed in endometrioid carcinoma tissues cells and negatively modulated by FOXP4-AS1, was identified as the downstream target molecule of FOXP4-AS1. Subsequently, the mechanistic experiments confirmed that, through binding to enhancer of zeste homolog 2 (EZH2; one of the catalytic subunits of polycomb repressive complex 2 [PRC2]), FOXP4-AS1 could epigenetically suppress the expression of DUSP5. Finally, the oncogenic function of the FOXP4-AS1/EZH2/DUSP5 axis in endometrioid carcinoma was confirmed via rescue assays. Conclusions: The findings of the present study have highlighted how FOXP4-AS1 fulfills an oncogenic role in endometrioid carcinoma, and targeting FOXP4-AS1 and its pathway may provide new biomarkers for patients with endometrioid carcinoma.

Hyaluronic Acid Viscosupplement Modulates Inflammatory Mediators in Chondrocyte and Macrophage Coculture via MAPK and NF-κB Signaling Pathways

Osteoarthritis (OA) is a chronic musculoskeletal disorder characterized by cartilage degeneration and synovial inflammation. Paracrine interactions between chondrocytes and macrophages play an essential role in the onset and progression of OA. In this study, in replicating the inflammatory response during OA pathogenesis, chondrocytes were treated with interleukin-1β (IL-1β), and macrophages were treated with lipopolysaccharide and interferon-γ. In addition, a coculture system was developed to simulate the biological situation in the joint. In this study, we examined the impact of hyaluronic acid (HA) viscosupplement, particularly Hyruan Plus, on chondrocytes and macrophages. Notably, this viscosupplement has demonstrated promising outcomes in reducing inflammation; however, the underlying mechanism of action remains elusive. The viscosupplement attenuated inflammation, showing an inhibitory effect on nitric oxide production, downregulating proinflammatory cytokines such as matrix metalloproteinases (MMP13 and MMP3), and upregulating the expression levels of type II collagen and aggrecan in chondrocytes. HA also reduced the expression level of inflammatory cytokines such as IL-1β, TNF-α, and IL-6 in macrophages, and HA exerted an overall protective effect by partially suppressing the MAPK pathway in chondrocytes and p65/NF-κB signaling in macrophages. Therefore, HA shows potential as a viscosupplement for treating arthritic joints.

LncRNA HOTAIR regulates autophagy and proliferation mechanisms in premature ovarian insufficiency through the miR-148b-3p/ATG14 axis

Premature ovarian insufficiency (POI) is a serious disease significantly affecting the physical and mental health of women of reproductive age, not just impacting fertility outcomes. Ovarian damage due to chemotherapy remains a major cause of this condition. Recent studies have indicated the involvement of the long non-coding RNA HOTAIR in the progression of various diseases, showcasing important biological functions, yet its role in POI remains unclear. We conducted microarray dataset analysis and qRT-PCR experiments, demonstrating downregulation of HOTAIR expression in ovarian tissue and granulosa cells. Various functional experiments using plasmids overexpressing HOTAIR confirmed its promotion of cisplatin-induced granulosa cell autophagy and proliferation. Mechanistically, dual-luciferase assays showed that HOTAIR modulates ATG14 levels in POI by binding miR-148b-3p, thereby enhancing levels of autophagy and proliferation. In this study, we first explored the impact of miR-148b-3p on POI and found that overexpression of miR-148b-3p reversed the promotion of autophagy and proliferation induced by HOTAIR overexpression. The inhibitory effect of miR-148b-3p inhibitor on KGN cell autophagy and proliferation improvement could also be reversed by silencing ATG14. Overall, our findings indicate the promoting role of HOTAIR in POI and its potential as a biomarker for POI by modulating the miR-148b-3p/ATG14 axis to improve mechanisms of autophagy and proliferation in POI.

The Landscape of microRNAs in Bone Tumor: A Comprehensive Review in Recent Studies

Cancer, the second greatest cause of mortality worldwide, frequently causes bone metastases in patients with advanced-stage carcinomas such as prostate, breast, and lung cancer. The existence of these metastases contributes to the occurrence of skeletal-related events (SREs), which are defined by excessive pain, pathological fractures, hypercalcemia, and spinal cord compression. These injurious incidents leave uncomfortably in each of the cancer patient's life quality. Primary bone cancers, including osteosarcoma (OS), chondrosarcoma (CS), and Ewing's sarcoma (ES), have unclear origins. MicroRNA (miRNA) expression patterns have been changed in primary bone cancers such as OS, CS, and ES, indicating a role in tumor development, invasion, metastasis, and treatment response. These miRNAs are persistent in circulation and exhibit distinct patterns in many forms of bone tumors, making them potential biomarkers for early detection and treatment of such diseases. Given their crucial regulatory functions in various biological processes and conditions, including cancer, this study aims to look at miRNAs' activities and possible contributions to bone malignancies, focusing on OS, CS, and ES. In conclusion, miRNAs are valuable tools for diagnosing, monitoring, and predicting OS, CS, and ES outcomes. Further research is required to fully comprehend the intricate involvement of miRNAs in these bone cancers and to develop effective miRNA-based treatments.

miRNA Expression Profiling in Human Breast Cancer Diagnostics and Therapy

Breast cancer is one of the most commonly diagnosed cancer types worldwide. Regarding molecular characteristics and classification, it is a heterogeneous disease, which makes it more challenging to diagnose. As is commonly known, early detection plays a pivotal role in decreasing mortality and providing a better prognosis for all patients. Different treatment strategies can be adjusted based on tumor progression and molecular characteristics, including personalized therapies. However, dealing with resistance to drugs and recurrence is a challenge. The therapeutic options are limited and can still lead to poor clinical outcomes. This review aims to shed light on the current perspective on the role of miRNAs in breast cancer diagnostics, characteristics, and prognosis. We discuss the potential role of selected non-coding RNAs most commonly associated with breast cancer. These include miR-21, miR-106a, miR-155, miR-141, let-7c, miR-335, miR-126, miR-199a, miR-101, and miR-9, which are perceived as potential biomarkers in breast cancer prognosis, diagnostics, and treatment response monitoring. As miRNAs differ in expression levels in different types of cancer, they may provide novel cancer therapy strategies. However, some limitations regarding dynamic alterations, tissue-specific profiles, and detection methods must also be raised.

Polynucleotides Suppress Inflammation and Stimulate Matrix Synthesis in an In Vitro Cell-Based Osteoarthritis Model

Osteoarthritis (OA) is characterized by degeneration of the joint cartilage, inflammation, and a change in the chondrocyte phenotype. Inflammation also promotes cell hypertrophy in human articular chondrocytes (HC-a) by activating the NF-κB pathway. Chondrocyte hypertrophy and inflammation promote extracellular matrix degradation (ECM). Chondrocytes depend on Smad signaling to control and regulate cell hypertrophy as well as to maintain the ECM. The involvement of these two pathways is crucial for preserving the homeostasis of articular cartilage. In recent years, Polynucleotides Highly Purified Technology (PN-HPT) has emerged as a promising area of research for the treatment of OA. PN-HPT involves the use of polynucleotide-based agents with controlled natural origins and high purification levels. In this study, we focused on evaluating the efficacy of a specific polynucleotide sodium agent, known as CONJURAN, which is derived from fish sperm. Polynucleotides (PN), which are physiologically present in the matrix and function as water-soluble nucleic acids with a gel-like property, have been used to treat patients with OA. However, the specific mechanisms underlying the effect remain unclear. Therefore, we investigated the effect of PN in an OA cell model in which HC-a cells were stimulated with interleukin-1β (IL-1β) with or without PN treatment. The CCK-8 assay was used to assess the cytotoxic effects of PN. Furthermore, the enzyme-linked immunosorbent assay was utilized to detect MMP13 levels, and the nitric oxide assay was utilized to determine the effect of PN on inflammation. The anti-inflammatory effects of PN and related mechanisms were investigated using quantitative PCR, Western blot analysis, and immunofluorescence to examine and analyze relative markers. PN inhibited IL-1β induced destruction of genes and proteins by downregulating the expression of MMP3, MMP13, iNOS, and COX-2 while increasing the expression of aggrecan (ACAN) and collagen II (COL2A1). This study demonstrates, for the first time, that PN exerted anti-inflammatory effects by partially inhibiting the NF-κB pathway and increasing the Smad2/3 pathway. Based on our findings, PN can potentially serve as a treatment for OA.

HOX cluster-embedded lncRNAs and epithelial-mesenchymal transition in cancer: Molecular mechanisms and therapeutic opportunities

Although there has been substantial improvement in the treatment modalities, cancer remains the major cause of fatality worldwide. Metastasis, recurrence, and resistance to oncological therapies are the leading causes of cancer mortality. Epithelial-mesenchymal transition (EMT) is a complex biological process that allows cancer cells to undergo morphological transformation into a mesenchymal phenotype to acquire invasive potential. It encompasses reversible and dynamic ontogenesis by neoplastic cells during metastatic dissemination. Hence, understanding the molecular landscape of EMT is imperative to identify a reliable clinical biomarker to combat metastatic spread. Accumulating evidence reveals the role of HOX (homeobox) cluster-embedded long non-coding RNAs (lncRNAs) in EMT and cancer metastasis. They play a crucial role in the induction of EMT, modulating diverse biological targets. The present review emphasizes the involvement of HOX cluster-embedded lncRNAs in EMT as a molecular sponge, chromatin remodeler, signaling regulator, and immune system modulator. Furthermore, the molecular mechanisms behind therapy resistance and the potential use of novel drugs targeting HOX cluster-embedded lncRNAs in the clinical management of distant metastasis will be discussed.

Insights into the role of long non-coding RNAs in DNA methylation mediated transcriptional regulation

DNA methylation is one of the most important epigenetic mechanisms that governing regulation of gene expression, aberrant DNA methylation patterns are strongly associated with human malignancies. Long non-coding RNAs (lncRNAs) have being discovered as a significant regulator on gene expression at the epigenetic level. Emerging evidences have indicated the intricate regulatory effects between lncRNAs and DNA methylation. On one hand, transcription of lncRNAs are controlled by the promoter methylation, which is similar to protein coding genes, on the other hand, lncRNA could interact with enzymes involved in DNA methylation to affect the methylation pattern of downstream genes, thus regulating their expression. In addition, circular RNAs (circRNAs) being an important class of noncoding RNA are also found to participate in this complex regulatory network. In this review, we summarize recent research progress on this crosstalk between lncRNA, circRNA, and DNA methylation as well as their potential functions in complex diseases including cancer. This work reveals a hidden layer for gene transcriptional regulation and enhances our understanding for epigenetics regarding detailed mechanisms on lncRNA regulatory function in human cancers.

Regulatory roles of noncoding RNAs in intervertebral disc degeneration as potential therapeutic targets (Review)

Intervertebral disc degeneration (IDD) is the leading cause of lower back pain, which is one of the primary factors that lead to disability and pose a serious economic burden. The key pathological processes involved are extracellular matrix degradation, autophagy, apoptosis, and inflammation of nucleus pulposus cells. Non-coding RNAs (ncRNAs), including microRNAs, long ncRNAs and circular RNAs, are key regulators of the aforementioned processes. ncRNAs are differentially expressed in tissues of the intervertebral disc between healthy individuals and patients and participate in the pathological progression of IDD via a complex pattern of gene regulation. However, the regulatory mechanisms of ncRNAs in IDD remain unclear. The present review summarizes the latest insights into the regulatory role of ncRNAs in IDD and sheds light on potentially novel therapeutic strategies for IDD that may be implemented in the future.

JSCSNCP-LMA: a method for predicting the association of lncRNA-miRNA

Non-coding RNAs (ncRNAs) have long been considered the "white elephant" on the genome because they lack the ability to encode proteins. However, in recent years, more and more biological experiments and clinical reports have proved that ncRNAs account for a large proportion in organisms. At the same time, they play a decisive role in the biological processes such as gene expression and cell growth and development. Recently, it has been found that short sequence non-coding RNA(miRNA) and long sequence non-coding RNA(lncRNA) can regulate each other, which plays an important role in various complex human diseases. In this paper, we used a new method (JSCSNCP-LMA) to predict lncRNA-miRNA with unknown associations. This method combined Jaccard similarity algorithm, self-tuning spectral clustering similarity algorithm, cosine similarity algorithm and known lncRNA-miRNA association networks, and used the consistency projection to complete the final prediction. The results showed that the AUC values of JSCSNCP-LMA in fivefold cross validation (fivefold CV) and leave-one-out cross validation (LOOCV) were 0.9145 and 0.9268, respectively. Compared with other models, we have successfully proved its superiority and good extensibility. Meanwhile, the model also used three different lncRNA-miRNA datasets in the fivefold CV experiment and obtained good results with AUC values of 0.9145, 0.9662 and 0.9505, respectively. Therefore, JSCSNCP-LMA will help to predict the associations between lncRNA and miRNA.

Effect of Diacerein on HOTAIR/IL-6/STAT3, Wnt/β-Catenin and TLR-4/NF-κB/TNF-α axes in colon carcinogenesis

Colorectal cancer (CRC) is a common malignancy with high mortality and poor prognosis. Diacerein (DIA) is an anti-inflammatory used for treatment of osteoarthritis. We delineated some underlying molecular mechanisms of DIA's anti-carcinogenic effect in CRC using in vivo and in vitro models. Human Caco-2 cells were treated with DIA followed by MTT and Annexin V assays and CRC was experimentally induced using 1,2-dimethylhydrazine. DIA (50 mg/kg/day, orally) was administrated for 8 weeks. The MTT assay confirmed cytotoxic effect of DIA in vitro and Annexin V confirmed its apoptotic effect. DIA resulted in regression of tumour lesions with reduced colonic TLR4, NF-κB and TNF-α protein levels and down-regulated VEGF expression, confirming anti-angiogenic impact. DIA triggered caspase-3 expression and regulated Wnt/β-Catenin pathway, by apparently interrupting the IL-6/STAT3/ lncRNA HOTAIR axis. In conclusion, DIA disrupted IL-6/STAT3/ lncRNA HOTAIR axis which could offer an effective therapeutic strategy for the management of CRC.

ALKBH5 regulates STAT3 activity to affect the proliferation and tumorigenicity of osteosarcoma via an m6A-YTHDF2-dependent manner

Background

N6-methyladenosine (m6A) is the most common and abundant mRNA modification and it plays crucial roles in many biological processes. However, as a key RNA demethylase, alkylation repair homolog protein 5 (ALKBH5) has not been well studied in human osteosarcoma. The present study sought to explore ALKBH5-mediated m6A modification and the underlying mechanisms in human osteosarcoma.

Methods

The expression of ALKBH5 and its correlation with clinicopathological features were examined by bioinformatics analysis and tissue microarrays. Cellular proliferation was detected by CCK8 assays. Cell cycle and apoptosis were analyzed by TUNEL and Flow cytometry assay. Finally, investigation of the regulatory mechanism of ALKBH5 in human osteosarcoma was performed by MeRIP assay, RNA-sequencing, dual luciferase reporter assay, RNA pull-down and RNA stability assay. Tumor xenograft models were established for in vivo experiments.

Findings

Our data showed that low expression of ALKBH5 was associated with worse overall survival for osteosarcoma patients. Reducing m6A mRNA levels in human osteosarcoma cells through ALKBH5 up-regulation lead to cell proliferation inhibition, cell apoptosis and cycle arrest. We identified SOCS3, a negative regulator of STAT3, as a downstream target of ALKBH5-mediated m6A modification. And the m6A modified SOCS3 mRNA was recognized by YTHDF2, which promotes the decay of SOCS3. Mechanistically, our data revealed that ALKBH5 inactivated STAT3 pathway by increasing SOCS3 expression via an m6A-YTHDF2-dependent manner.

Interpretation

M6A methylation is rising as a pathway affecting tumorigenicity and tumor progression. Our findings illuminate the clinical significance of ALKBH5-mediated m6A modification in human osteosarcoma and the regulatory mechanisms underlying tumor proliferation and growth, suggesting that ALKBH5 is a potential biomarker for treatment in human osteosarcoma.

Funding

This work was supported by and Science and Technology foundation of Hubei, China (Grant No.2017CFB762); the Tongji hospital foundation (Grant No.2201103013); and the National Natural Science Foudation of China (No.82002849).

LncRNA-mediated DNA methylation: an emerging mechanism in cancer and beyond

DNA methylation is one of the most important epigenetic mechanisms to regulate gene expression, which is highly dynamic during development and specifically maintained in somatic cells. Aberrant DNA methylation patterns are strongly associated with human diseases including cancer. How are the cell-specific DNA methylation patterns established or disturbed is a pivotal question in developmental biology and cancer epigenetics. Currently, compelling evidence has emerged that long non-coding RNA (lncRNA) mediates DNA methylation in both physiological and pathological conditions. In this review, we provide an overview of the current understanding of lncRNA-mediated DNA methylation, with emphasis on the roles of this mechanism in cancer, which to the best of our knowledge, has not been systematically summarized. In addition, we also discuss the potential clinical applications of this mechanism in RNA-targeting drug development.

The Roles of Noncoding RNAs in the Development of Osteosarcoma Stem Cells and Potential Therapeutic Targets

Osteosarcoma (OS) is the common bone tumor in children and adolescents. Because of chemotherapy resistance, the OS patients have a poor prognosis. The one reason of chemotherapeutic resistance is the development of cancer stem cells (CSCs). CSCs represent a small portion of tumor cells with the capacity of self-renewal and multipotency, which are associated with tumor initiation, metastasis, recurrence and drug resistance. Recently, noncoding RNAs (ncRNAs) have been reported to critically regulate CSCs. Therefore, in this review article, we described the role of ncRNAs, especially miRNAs, lncRNAs and circRNAs, in regulating CSCs development and potential mechanisms. Specifically, we discussed the role of multiple miRNAs in targeting CSCs, including miR-26a, miR-29b, miR-34a, miR-133a, miR-143, miR-335, miR-382, miR-499a, miR-1247, and let-7days. Moreover, we highlighted the functions of lncRNAs in regulating CSCs in OS, such as B4GALT1-AS1, DANCR, DLX6-AS1, FER1L4, HIF2PUT, LINK-A, MALAT1, SOX2-OT, and THOR. Due to the critical roles of ncRNAs in regulation of OS CSCs, targeting ncRNAs might be a novel strategy for eliminating CSCs for OS therapy.

Targeting long non coding RNA by natural products: Implications for cancer therapy

In spite of achieving substantial progress in its therapeutic strategies, cancer-associated prevalence and mortality are persistently rising globally. However, most malignant cancers either cannot be adequately diagnosed at the primary phase or resist against multiple treatments such as chemotherapy, surgery, radiotherapy as well as targeting therapy. In recent decades, overwhelming evidences have provided more convincing words on the undeniable roles of long non-coding RNAs (lncRNAs) in incidence and development of various cancer types. Recently, phytochemical and nutraceutical compounds have received a great deal of attention due to their inhibitory and stimulatory effects on oncogenic and tumor suppressor lncRNAs respectively that finally may lead to attenuate various processes of cancer cells such as growth, proliferation, metastasis and invasion. Therefore, application of phytochemicals with anticancer characteristics can be considered as an innovative approach for treating cancer and increasing the sensitivity of cancer cells to standard prevailing therapies. The purpose of this review was to investigate the effect of various phytochemicals on regulation of lncRNAs in different human cancer and evaluate their capabilities for cancer treatment and prevention.

The Role of lncRNAs in Rare Tumors with a Focus on HOX Transcript Antisense RNA (HOTAIR)

Rare cancers are identified as those with an annual incidence of fewer than 6 per 100,000 persons and includes both epithelial and stromal tumors from different anatomical areas. The advancement of analytical methods has produced an accurate molecular characterization of most human cancers, suggesting a “molecular classification” that has allowed the establishment of increasingly personalized therapeutic strategies. However, the limited availability of rare cancer samples has resulted in very few therapeutic options for these tumors, often leading to poor prognosis. Long non coding RNAs (lncRNAs) are a class of non-coding RNAs mostly involved in tumor progression and drug response. In particular, the lncRNA HOX transcript antisense RNA (HOTAIR) represents an emergent diagnostic, prognostic and predictive biomarker in many human cancers. The aim of this review is to highlight the role of HOTAIR in rare cancers, proposing it as a new biomarker usable in the management of these tumors.

HOTAIR beyond repression: In protein degradation, inflammation, DNA damage response, and cell signaling

Long noncoding RNAs (lncRNAs) are pervasively transcribed from the mammalian genome as transcripts that are usually >200 nucleotides long. LncRNAs generally do not encode proteins but are involved in a variety of physiological processes, principally as epigenetic regulators. HOX transcript antisense intergenic RNA (HOTAIR) is a well-characterized lncRNA that has been implicated in several cancers and in various other diseases. HOTAIR is a repressor lncRNA and regulates various repressive chromatin modifications. However, recent studies have revealed additional functions of HOTAIR in regulation of protein degradation, microRNA (miRNA) sponging, NF-κB activation, inflammation, immune signaling, and DNA damage response. Herein, we have summarized the diverse functions and modes of action of HOTAIR in protein degradation, inflammation, DNA repair, and diseases, beyond its established functions in gene silencing.

Epigenetic regulation of autophagy: A key modification in cancer cells and cancer stem cells

Aberrant epigenetic alterations play a decisive role in cancer initiation and propagation via the regulation of key tumor suppressor genes and oncogenes or by modulation of essential signaling pathways. Autophagy is a highly regulated mechanism required for the recycling and degradation of surplus and damaged cytoplasmic constituents in a lysosome dependent manner. In cancer, autophagy has a divergent role. For instance, autophagy elicits tumor promoting functions by facilitating metabolic adaption and plasticity in cancer stem cells (CSCs) and cancer cells. Moreover, autophagy exerts pro-survival mechanisms to these cancerous cells by influencing survival, dormancy, immunosurveillance, invasion, metastasis, and resistance to anti-cancer therapies. In addition, recent studies have demonstrated that various tumor suppressor genes and oncogenes involved in autophagy, are tightly regulated via different epigenetic modifications, such as DNA methylation, histone modifications and non-coding RNAs. The impact of epigenetic regulation of autophagy in cancer cells and CSCs is not well-understood. Therefore, uncovering the complex mechanism of epigenetic regulation of autophagy provides an opportunity to improve and discover novel cancer therapeutics. Subsequently, this would aid in improving clinical outcome for cancer patients. In this review, we provide a comprehensive overview of the existing knowledge available on epigenetic regulation of autophagy and its importance in the maintenance and homeostasis of CSCs and cancer cells.

Soft Tissue Sarcoma: An Insight on Biomarkers at Molecular, Metabolic and Cellular Level

Simple Summary

Soft tissue sarcoma is a rare mesenchymal malignancy. Despite the advancements in the fields of radiology, pathology and surgery, these tumors often recur locally and/or with metastatic disease. STS is considered to be a diagnostic challenge due to the large variety of histological subtypes with clinical and histopathological characteristics which are not always distinct. One of the important clinical problems is a lack of useful biomarkers. Therefore, the discovery of biomarkers that can be used to detect tumors or predict tumor response to chemotherapy or radiotherapy could help clinicians provide more effective clinical management.

Abstract

Soft tissue sarcomas (STSs) are a heterogeneous group of rare tumors. Although constituting only 1% of all human malignancies, STSs represent the second most common type of solid tumors in children and adolescents and comprise an important group of secondary malignancies. Over 100 histologic subtypes have been characterized to date (occurring predominantly in the trunk, extremity, and retroperitoneum), and many more are being discovered due to molecular profiling. STS mortality remains high, despite adjuvant chemotherapy. New prognostic stratification markers are needed to help identify patients at risk of recurrence and possibly apply more intensive or novel treatments. Recent scientific advancements have enabled a more precise molecular characterization of sarcoma subtypes and revealed novel therapeutic targets and prognostic/predictive biomarkers. This review aims at providing a comprehensive overview of the most relevant cellular, molecular and metabolic biomarkers for STS, and highlight advances in STS-related biomarker research.

LncRNA MEG8 promotes TNF-α expression by sponging miR-454-3p in bone-invasive pituitary adenomas

There are few studies on the mechanism of pituitary adenoma (PA) destroying bone. The current study aimed to investigate the role of MEG8/miR-454-3p/TNF-α in bone-invasive pituitary adenomas (BIPAs). In this study, we report that lncRNA MEG8 and TNF-α are upregulated in BIPA tissues while miR-454-3p is downregulated, which is associated with poor progression-free survival (PFS). Functional assays revealed the role of up-regulated MEG8 and down-regulated miR-454-3p in promoting bone destruction. Mechanistically, MEG8 promotes TNF-α expression by sponging miR-454-3p, which ultimately leads to the occurrence of bone destruction. The mechanism is confirmed in vivo and in vitro. Therefore, our data illustrated a new regulatory mechanism of MEG8/miR-454-3p/TNF-α in BIPAs. It may provide a useful strategy for diagnosis and treatment for BIPA patients.

LncRNAs as Therapeutic Targets for Autophagy-involved Cardiovascular Diseases: A Review of Molecular Mechanism and T herapy Strategy

BACKGROUND

Cardiovascular diseases (CVDs) remain the leading cause of death worldwide. The concept of precision medicine in CVD therapy today requires the incorporation of individual genetic and environmental variability to achieve personalized disease prevention and tailored treatment. Autophagy, an evolutionarily conserved intracellular degradation process, has been demonstrated to be essential in the pathogenesis of various CVDs. Nonetheless, there have been no effective treatments for autophagy- involved CVDs. Long noncoding RNAs (lncRNAs) are noncoding RNA sequences that play versatile roles in autophagy regulation, but much needs to be explored about the relationship between lncRNAs and autophagy-involved CVDs.

SUMMARY

Increasing evidence has shown that lncRNAs contribute considerably to modulate autophagy in the context of CVDs. In this review, we first summarize the current knowledge of the role lncRNAs play in cardiovascular autophagy and autophagy-involved CVDs. Then, recent developments of antisense oligonucleotides (ASOs) designed to target lncRNAs to specifically modulate autophagy in diseased hearts and vessels are discussed, focusing primarily on structure-activity relationships of distinct chemical modifications and relevant clinical trials.

PERSPECTIVE

ASOs are promising in cardiovascular drug innovation. We hope that future studies of lncRNA-based therapies would overcome existing technical limitations and help people who suffer from autophagy-involved CVDs.

Long noncoding RNAs in bacterial infection

Infectious and inflammatory diseases remain major causes of mortality and morbidity worldwide. To combat bacterial infections, the mammalian immune system employs a myriad of regulators, which secure the effective initiation of inflammatory responses while preventing pathologies due to overshooting immunity. Recently, the human genome has been shown to be pervasively transcribed and to generate thousands of still poorly characterized long noncoding RNAs (lncRNAs). A growing body of literature suggests that lncRNAs play important roles in the regulatory circuitries controlling innate and adaptive immune responses to bacterial pathogens. This review provides an overview of the roles of lncRNAs in the interaction of human and rodent host cells with bacterial pathogens. Further decoding of the lncRNA networks that underlie pathological inflammation and immune subversion could provide new insights into the host cell mechanisms and microbial strategies that determine the outcome of bacterial infections. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Long non-coding RNA SNHG1 stimulates ovarian cancer progression by modulating expression of miR-454 and ZEB1

Ovarian cancer (OC) is highly prevalent and is associated with high mortality rates due to metastasis and relapse. In this study, we assessed the role of long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) in OC to gain further insight into mechanisms that contribute to its aggressiveness. We analyzed the correlation between SNHG1, miR-454 and zinc finger E-box-binding homeobox 1 (ZEB1) using a dual-luciferase reporter assay. Alterations in cell metastasis and invasiveness were observed using wound-healing and Transwell invasion assays, respectively. Tumor xenografts allowed us to monitor liver metastasis of mice injected with A2780 cells. We found that SNHG1 is overexpressed in OC. Downregulation of SNHG1 promoted miR-454 expression and reduced ZEB1 levels. In addition, knockdown of SNHG1, also reduced the aggressiveness of A2780 and SK-OV3 cells. Furthermore, SNHG1 downregulation by siRNA hindered cell migration and invasion; however, this effect was reversed by co-transfection of miR-454 into A2780 and SK-OV3 cells. Moreover, SNHG1 increased ZEB1 expression by downregulating miR-454 and activated Akt signaling, thereby promoting epithelial-mesenchymal transition and enhancing the invasiveness of OC cells. Tumor xenograft analyses confirmed that SNHG1 affects OC proliferation and metastasis in vivo. In summary, our data demonstrate that SNHG1 plays crucial roles in tumor progression and may be a useful maker for OC prognosis.

Epigenetic Regulation of MicroRNA Clusters and Families during Tumor Development

MicroRNAs are small non-coding single-stranded RNA molecules regulating gene expression on a post-transcriptional level based on the seed sequence similarity. They are frequently clustered; thus, they are either simultaneously transcribed into a single polycistronic transcript or they may be transcribed independently. Importantly, microRNA families that contain the same seed region and thus target related signaling proteins, may be localized in one or more clusters, which are in a close relationship. MicroRNAs are involved in basic physiological processes, and their deregulation is associated with the origin of various pathologies, including solid tumors or hematologic malignancies. Recently, the interplay between the expression of microRNA clusters and families and epigenetic machinery was described, indicating aberrant DNA methylation or histone modifications as major mechanisms responsible for microRNA deregulation during cancerogenesis. In this review, the most studied microRNA clusters and families affected by hyper- or hypomethylation as well as by histone modifications are presented with the focus on particular mechanisms. Finally, the diagnostic and prognostic potential of microRNA clusters and families is discussed together with technologies currently used for epigenetic-based cancer therapies.

miR-454-3p prevents ox-LDL-induced apoptosis in HAECs by targeting TRPC3

Endothelial-cell (EC) apoptosis serves a vital role in the pathogenesis of atherosclerosis. Accumulating evidence has implicated microRNA (miRNA/miR) dysregulation in EC apoptosis. Although the role of miR-454-3p in carcinogenesis has been well documented, its role and underlying mechanism in EC apoptosis remain unclear. In the present study, the results revealed that miR-454-3p expression was substantially downregulated in human aortic endothelial cells (HAECs) following oxidized low-density lipoprotein (ox-LDL) treatment. miR-454-3p suppression significantly attenuated the viability of HAECs, while miR-454-3p overexpression repressed ox-LDL-induced HAEC apoptosis. Bioinformatics analysis and luciferase reporter assays revealed that transient receptor potential canonical 3 (TRPC3), a key regulator of atherosclerosis development, was the direct target of miR-454-3p. Furthermore, TRPC3 overexpression abolished the anti-apoptotic effect of miR-454-3p on HAECs. These results revealed a novel role of miR-454-3p in ox-LDL-induced apoptosis in HAECs.

Functional Interaction among lncRNA HOTAIR and MicroRNAs in Cancer and Other Human Diseases

Simple Summary

This review aimed to describe the contribution of functional interaction between the lncRNA HOTAIR and microRNAs in human diseases, including cancer. HOTAIR/miRNAs complexes interfere with different cellular processes during carcinogenesis, mainly deregulating a series of oncogenic signaling pathways. A great number of ncRNAs-related databases have been established, supported by bioinformatics technologies, to identify the ncRNA-mediated sponge regulatory network. These approaches need experimental validation through cells and animal models studies. The optimization of systems to interfere with HOTAIR/miRNAs interplay could represent a new tool for the definition of diagnostic therapeutics in cancer patients.

Abstract

LncRNAs are a class of non-coding RNAs mostly involved in regulation of cancer initiation, metastatic progression, and drug resistance, through participation in post-transcription regulatory processes by interacting with different miRNAs. LncRNAs are able to compete with endogenous RNAs by binding and sequestering miRNAs and thereby regulating the expression of their target genes, often represented by oncogenes. The lncRNA HOX transcript antisense RNA (HOTAIR) represents a diagnostic, prognostic, and predictive biomarker in many human cancers, and its functional interaction with miRNAs has been described as crucial in the modulation of different cellular processes during cancer development. The aim of this review is to highlight the relation between lncRNA HOTAIR and different microRNAs in human diseases, discussing the contribution of these functional interactions, especially in cancer development and progression.

The Biological Roles of lncRNAs and Future Prospects in Clinical Application

Chemo and radiation therapies are the most commonly used therapies for cancer, but they can induce DNA damage, resulting in the apoptosis of host cells. DNA double-stranded breaks (DSBs) are the most lethal form of DNA damage in cells, which are constantly caused by a wide variety of genotoxic agents, both environmentally and endogenously. To maintain genomic integrity, eukaryotic organisms have developed a complex mechanism for the repair of DNA damage. Researches reported that many cellular long noncoding RNAs (lncRNAs) were involved in the response of DNA damage. The roles of lncRNAs in DNA damage response can be regulated by the dynamic modification of N6-adenosine methylation (m6A). The cellular accumulation of DNA damage can result in various diseases, including cancers. Additionally, lncRNAs also play roles in controlling the gene expression and regulation of autophagy, which are indirectly involved with individual development. The dysregulation of these functions can facilitate human tumorigenesis. In this review, we summarized the origin and overview function of lncRNAs and highlighted the roles of lncRNAs involved in the repair of DNA damage.

SP1-induced long non-coding RNA SNHG6 facilitates the carcinogenesis of chondrosarcoma through inhibiting KLF6 by recruiting EZH2

Small nucleolar RNA host gene 6 (SNHG6) is a newly discovered long non-coding RNA (lncRNA), while the regulatory mechanism of SNHG6 in chondrosarcoma is largely unknown. Here we found that SNHG6 expression was upregulated and showed positive correlation with the progression of chondrosarcoma. Functional assays demonstrated that SNHG6 was required for the proliferation, migration, and invasion of chondrosarcoma cells. Mechanistic study revealed that SNHG6 could recruit EZH2 and maintain high level of H3K27me3 to repress the transcription of tumor-suppressor genes, including KLF6. KLF6 was found to bind to the promoter region of SP1 and restrained its transcription, while SP1 could be recruited to the promoter region of SNHG6 and promoted its transcription to form a positive loop. In summary, this study reveals that SP1-induced SNHG6 forms a positive loop to facilitate the carcinogenesis of chondrosarcoma through the suppression of KLF6 by recruiting EZH2, which manifests the oncogenic function of SNHG6 in chondrosarcoma.

Dual relationship between long non-coding RNAs and STAT3 signaling in different cancers: New insight to proliferation and metastasis

Uncontrolled growth and metastasis of cancer cells is an increasing challenge for overcoming cancer, and improving survival of patients. Complicated signaling networks account for proliferation and invasion of cancer cells that need to be elucidated for providing effective cancer therapy, and minimizing their malignancy. Long non-coding RNAs (lncRNAs) are RNA molecules with a length of more than 200 nucleotides. They participate in cellular events, and their dysregulation in a common phenomenon in different cancers. Noteworthy, lncRNAs can regulate different molecular pathways, and signal transducer and activator of transcription 3 (STAT3) is one of them. STAT3 is a tumor-promoting factors in cancers due to its role in cancer proliferation (cell cycle progression and apoptosis inhibition) and metastasis (EMT induction). LncRNAs can function as upstream mediators of STAT3 pathway, reducing/enhancing its expression. This dual relationship is of importance in affecting proliferation and metastasis of cancer cells. The response of cancer cells to therapy such as chemotherapy and radiotherapy is regulated by lncRNA/STAT3 axis. Tumor-promoting lncRNAs including NEAT1, SNHG3 and H19 induces STAT3 expression, while tumor-suppressing lncRNAs such as MEG3, PTCSC3 and NKILA down-regulate STAT3 expression. Noteworthy, upstream mediators of STAT3 such as microRNAs can be regulated by lncRNAs. These complicated signaling networks are mechanistically described in the current review.

EZH2-Inhibited MicroRNA-454-3p Promotes M2 Macrophage Polarization in Glioma

Glioma is a primary intracranial tumor with high incidence and mortality. The oncogenic role of EZH2 has been reported in glioma. EZH2 inhibited microRNA-454-3p (miR-454-3p) by binding to its promoter in chondrosarcoma cells. Therefore, our study aimed to identify whether EZH2 regulated M2 macrophage polarization in glioma via miR-454-3p. Clinical samples of different grades of glioma and glioma cells were collected and immunohistochemistry and RT-qPCR demonstrated that EZH2 was highly expressed in glioma tissues. Expression of EZH2 was positively correlated with the degree of M2 macrophage polarization in glioma tissues. EZH2 was silenced by lentivirus in glioma cells, which were subsequently co-cultured with macrophages to evaluate its effect on macrophage polarization. miR-454-3p, a down-regulated miR in glioma, was found to be increased after silencing of EZH2. Furthermore, MethPrimer analysis showed that EZH2 silencing inhibited the DNA methylation level of miR-454-3p. Additionally, MS-PCR, dual-luciferase reporter, RIP and RNA pull down assays revealed that miR-454-3p promoted PTEN expression by inhibiting m⁶A modification through binding to the enzyme YTHDF2. Either inhibition of miR-454-3p or PTEN resulted in promotion of M2 macrophage polarization. Collectively, histone methyltransferase EZH2 inhibited miR-454-3p through methylation modification and promoted m⁶A modification of PTEN to induce glioma M2 macrophage polarization.

Sirtuins' control of autophagy and mitophagy in cancer

Mammalian cells use a specialized and complex machinery for the removal of altered proteins or dysfunctional organelles. Such machinery is part of a mechanism called autophagy. Moreover, when autophagy is specifically employed for the removal of dysfunctional mitochondria, it is called mitophagy. Autophagy and mitophagy have important physiological implications and roles associated with cellular differentiation, resistance to stresses such as starvation, metabolic control and adaptation to the changing microenvironment. Unfortunately, transformed cancer cells often exploit autophagy and mitophagy for sustaining their metabolic reprogramming and growth to a point that autophagy and mitophagy are recognized as promising targets for ongoing and future antitumoral therapies. Sirtuins are NAD+ dependent deacylases with a fundamental role in sensing and modulating cellular response to external stresses such as nutrients availability and therefore involved in aging, oxidative stress control, inflammation, differentiation and cancer. It is clear, therefore, that autophagy, mitophagy and sirtuins share many common aspects to a point that, recently, sirtuins have been linked to the control of autophagy and mitophagy. In the context of cancer, such a control is obtained by modulating transcription of autophagy and mitophagy genes, by post translational modification of proteins belonging to the autophagy and mitophagy machinery, by controlling ROS production or major metabolic pathways such as Krebs cycle or glutamine metabolism. The present review details current knowledge on the role of sirtuins, autophagy and mitophagy in cancer to then proceed to discuss how sirtuins can control autophagy and mitophagy in cancer cells. Finally, we discuss sirtuins role in the context of tumor progression and metastasis indicating glutamine metabolism as an example of how a concerted activation and/or inhibition of sirtuins in cancer cells can control autophagy and mitophagy by impinging on the metabolism of this fundamental amino acid.

LncRNA, Important Player in Bone Development and Disease

BACKGROUND

Bone is an important tissue and its normal function requires tight coordination of transcriptional networks and signaling pathways, and many of these networks/ pathways are dysregulated in pathological conditions affecting cartilage and bones. Long non-coding RNA (lncRNA) refers to a class of RNAs with a length of more than 200 nucleotides, lack of protein-coding potential, and exhibiting a wide range of biological functions. Although studies on lcnRNAs are still in their infancy, they have emerged as critical players in bone biology and bone diseases. The functions and exact mechanism of bone-related lncRNAs have not been fully classified yet.

OBJECTIVE

The objective of this article is to summarize the current literature on lncRNAs on the basis of their role in bone biology and diseases, focusing on their emerging molecular mechanism, pathological implications and therapeutic potential.

DISCUSSION

A number of lncRNAs have been identified and shown to play important roles in multiple bone cells and bone disease. The function and mechanism of bone-related lncRNA remain to be elucidated.

CONCLUSION

At present, majority of knowledge is limited to cellular levels and less is known on how lncRNAs could potentially control the development and homeostasis of bone. In the present review, we highlight some lncRNAs in the field of bone biology and bone disease. We also delineate some lncRNAs that might have deep impacts on understanding bone diseases and providing new therapeutic strategies to treat these diseases.

Prognostic significance of an autophagy-related long non-coding RNA signature in patients with oral and oropharyngeal squamous cell carcinoma

Traditional clinicopathological indices are insufficient in predicting the prognosis of patients diagnosed with oral and oropharyngeal squamous cell carcinoma (OSCC/OPSCC). Notably, autophagy and long non-coding RNAs (lncRNAs) regulate the development and progression of various types of cancer. The present study aimed to assess the association between autophagy-related lncRNAs and the prognosis of patients diagnosed with OSCC/OPSCC. Gene sequencing and clinicopathological data of patients with OSCC/OPSCC were downloaded from The Cancer Genome Atlas database, while gene set functional classification was downloaded from the Gene Set Enrichment Analysis database. Out of the 413 transcriptome data samples and 402 clinicopathological data samples retrieved, a total of nine autophagy-related lncRNAs, including PTCSC2, AC099850.3, LINC01963, RTCA-AS1, AP002884.1, UBAC2-AS1, AL512274.1, MIR600HG and AL354733.3, were screened. This was geared towards establishing a signature through gene co-expression network, univariate and Least Absolute Shrinkage and Selection Operator Cox regression analyses. Based on this signature, the patients were subdivided into a high-risk group and a low-risk group. Kaplan-Meier survival analysis revealed that the overall survival of the high-risk group was significantly lower than that of the low-risk group. Furthermore, principal components analysis demonstrated that the patients diagnosed with OSCC/OPSCC could be distinguished into low-survival and high-survival groups according to the signature. Univariate and multivariate Cox regression analyses of clinicopathological data and the signature revealed that the signature could potentially be used as an independent prognostic factor for OSCC/OPSCC. In addition, reverse transcription-quantitative PCR analysis of clinical samples demonstrated the validity of the signature. In summary, the present study revealed that the signature based on autophagy-related lncRNAs potentially acts as an independent prognostic indicator for patients with OSCC/OPSCC. Furthermore, it promotes research on targeted diagnosis and treatment of patients diagnosed with OSCC/OPSCC.

Autophagy-related long noncoding RNAs can predict prognosis in patients with bladder cancer

We investigated whether autophagy-related long noncoding RNAs (lncRNAs) can predict prognosis in bladder cancer. We obtained bladder cancer lncRNA data from The Cancer Genome Atlas and autophagy-related genes from the Human Autophagy Database. Fifteen autophagy-related lncRNAs with prognostic significance were identified. Multivariate Cox analysis was used to construct a risk score model, which divided bladder cancer patients into high-risk and low-risk groups. We found that patients in the low-risk group had better survival than those in the high-risk group. Subgroup analysis showed that patients in the high-risk group also had worse OS than that in the low-risk group in subgroups based on age, gender, clinical stage, and TNM stage. We next established a nomogram according to the results of multivariate Cox regression, which included age, gender, clinical stage, TNM stage, and risk score. The area under the curve for 3- and 5-year overall survival predicted by the nomogram were 0.711 and 0.719, respectively. Bioinformatics analysis demonstrated that the 15 identified lncRNAs are involved in the cell cycle, DNA replication, cell adhesion, cancer pathway, WNT signaling pathway, and oxidative stress. These findings confirm that autophagy-related lncRNAs are predictive of prognosis in bladder cancer patients and may affect tumor progression.

Long Noncoding RNA HOXA11-AS Modulates the Resistance of Nasopharyngeal Carcinoma Cells to Cisplatin via miR-454-3p/c-Met

To elucidate the mechanism of action of HOXA11-AS in modulating the cisplatin resistance of nasopharyngeal carcinoma (NPC) cells. HOXA11-AS and miR-454-3p expression in NPC tissue and cisplatin-resistant NPC cells were measured via quantitative reverse transcriptase polymerase chain reaction. NPC parental cells (C666-1 and HNE1) and cisplatin-resistant cells (C666-1/DDP and HNE1/DDP) were transfected and divided into different groups, after which the MTT method was used to determine the inhibitory concentration 50 (IC50) of cells treated with different concentrations of cisplatin. Additionally, a clone formation assay, flow cytometry and Western blotting were used to detect DDP-induced changes. Thereafter, xenograft mouse models were constructed to verify the in vitro results. Obviously elevated HOXA11-AS and reduced miR-454-3p were found in NPC tissue and cisplatin-resistant NPC cells. Compared to the control cells, cells in the si-HOXA11-AS group showed sharp decreases in cell viability and IC50, and these results were reversed in the miR-454-3p inhibitor group. Furthermore, HOXA11-AS targeted miR-454-3p, which further targeted c-Met. In comparison with cells in the control group, HNE1/DDP and C666-1/DDP cells in the si-HOXA11-AS group demonstrated fewer colonies, with an increase in the apoptotic rate, while the expression levels of c-Met, p-Akt/Akt and p-mTOR/mTOR decreased. Moreover, the si-HOXA11-AS-induced enhancement in sensitivity to cisplatin was abolished by miR-454-3p inhibitor transfection. The in vivo experiment showed that DDP in combination with si-HOXA11-AS treatment could inhibit the growth of xenograft tumors. Silencing HOXA11-AS can inhibit the c-Met/AKT/mTOR pathway by specifically upregulating miR-454-3p, thus promoting cell apoptosis and enhancing the sensitivity of cisplatin-resistant NPC cells to cisplatin.

Regulatory effects of noncoding RNAs on the interplay of oxidative stress and autophagy in cancer malignancy and therapy

Noncoding RNAs (ncRNAs) regulation of various diseases including cancer has been extensively studied. Reactive oxidative species (ROS) elevated by oxidative stress are associated with cancer progression and drug resistance, while autophagy serves as an ROS scavenger in cancer cells. However, the regulatory effects of ncRNAs on autophagy and ROS in various cancer cells remains complex. Here, we explore how currently investigated ncRNAs, mainly miRNAs and lncRNAs, are involved in ROS production through modulating antioxidant genes. The regulatory effects of miRNAs and lncRNAs on autophagy-related (ATG) proteins to control autophagy activity in cancer cells are discussed. Moreover, differential expression of ncRNAs in tumor and normal tissues of cancer patients are further analyzed using The Cancer Genome Atlas (TCGA) database. This review hypothesizes links between ATG genes- or antioxidant genes-modulated ncRNAs and ROS production, which might result in tumorigenesis, malignancy, and cancer recurrence. A better understanding of the regulation of ROS and autophagy by ncRNAs might advance the use of ncRNAs as diagnostic and prognostic markers as well as therapeutic targets in cancer therapy.

MicroRNA-454-3p inhibits cell proliferation and invasion in esophageal cancer by targeting insulin-like growth factor 2 mRNA-binding protein 1

Esophageal cancer (ESCA) is the eighth most common cause of cancer-associated mortality in humans. An increasing number of studies have demonstrated that microRNAs (miRs) serve important roles in mediating tumor initiation and progression. miR-454-3p has been found to be involved in the development of various human malignancies; however, little is known about the role of miR-454-3p in esophageal cancer. In the present study, the protein and gene expression levels of miR-454-3p in ESCA tissues and cells were downregulated compared with adjacent normal tissues and normal human esophageal epithelial cells. Additionally, miR-454-3p downregulation resulted in improved survival rates in patients with ESCA, and miR-454-3p overexpression significantly suppressed cell proliferation, migration and invasion and promoted apoptosis in four ESCA cell lines (EC9706, ECA109, TE-1 and TE-8). It was found that miR-454-3p overexpression inhibited the expression of insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) at the protein and mRNA expression levels. Furthermore, it was demonstrated that miR-454-3p inhibited ESCA cell proliferation, migration and apoptosis by targeting IGF2BP1 via the ERK and AKT signaling pathways in a subcutaneous xenograft tumor mouse model. These results showed that miR-454-3p functioned as an important tumor suppressor in ESCA by targeting IGFBP1. Therefore, miR-454-3p may be a novel prognostic biomarker and therapeutic target for patients with ESCA.

The Roles of ceRNAs-Mediated Autophagy in Cancer Chemoresistance and Metastasis

Simple Summary

Chemoresistance and metastasis are the main causes of treatment failure in cancers. Autophagy contribute to the survival and metastasis of cancer cells. Competing endogenous RNA (ceRNA), particularly long non-coding RNAs and circular RNA (circRNA), can bridge the interplay between autophagy and chemoresistance or metastasis in cancers via sponging miRNAs. This review aims to discuss on the function of ceRNA-mediated autophagy in the process of metastasis and chemoresistance in cancers. ceRNA network can sequester the targeted miRNA expression to indirectly upregulate the expression of autophagy-related genes, and thereof participate in autophagy-mediated chemoresistance and metastasis. Our clarification of the mechanism of autophagy regulation in metastasis and chemoresistance may greatly improve the efficacy of chemotherapy and survival in cancer patients. The combination of the tissue-specific miRNA delivery and selective autophagy inhibitors, such as hydroxychloroquine, is attractive to treat cancer patients in the future.

Abstract

Chemoresistance and metastasis are the main causes of treatment failure and unfavorable outcome in cancers. There is a pressing need to reveal their mechanisms and to discover novel therapy targets. Autophagy is composed of a cascade of steps controlled by different autophagy-related genes (ATGs). Accumulating evidence suggests that dysregulated autophagy contributes to chemoresistance and metastasis via competing endogenous RNA (ceRNA) networks including lncRNAs and circRNAs. ceRNAs sequester the targeted miRNA expression to indirectly upregulate ATGs expression, and thereof participate in autophagy-mediated chemoresistance and metastasis. Here, we attempt to summarize the roles of ceRNAs in cancer chemoresistance and metastasis through autophagy regulation.

The Role of lncRNA Crosstalk in Leading Cancer Metastasis of Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common type of human malignancy. For decades, research into HNSCC invasion and metastasis has been dedicated to the study of protein-coding genes. Along with whole-genome and transcriptome sequencing development, long non-coding RNA (lncRNA) has attracted greater attention. Compelling evidence has proven the critical role of lncRNAs in the occurrence and development of HNSCC by means of epigenetic modifications, regulation of gene transcription, and post-transcription level. More importantly, crosstalk between lncRNAs and microRNAs was recently proven to regulate HNSCC metastasis through EMT modification. Based on these, this review summarizes the critical roles of lncRNAs in HNSCC metastasis and the crosstalk between lncRNAs and microRNAs as well as the detailed regulatory mechanism of the interaction. Thus, a deeper understanding of the lncRNA network in cancer metastasis is finally uncovered in order to provide a rationale and innovative concepts toward new therapeutic strategies for the highly metastatic HNSCC.

The roles of long noncoding RNAs in breast cancer metastasis

Breast cancer is the most significant threat to female health. Breast cancer metastasis is the major cause of mortality in breast cancer patients. To fully unravel the molecular mechanisms that underlie the breast cancer cell metastasis is critical for developing strategies to improve survival and prognosis in breast cancer patients. Recent studies have revealed that the long noncoding RNAs (lncRNAs) are involved in breast cancer metastasis through a variety of molecule mechanisms, though the precise functional details of these lncRNAs are yet to be clarified. In the present review, we focus on the functions of lncRNAs in breast cancer invasion and metastasis, with particular emphasis on the functional properties, the regulatory factors, the therapeutic promise, as well as the future challenges in studying these lncRNA.

Mechanisms of JAK-STAT signaling pathway mediated by CXCL8 gene silencing on epithelial-mesenchymal transition of human cutaneous melanoma cells

Effect of CXCL8 gene silencing-mediated JAK-STAT signaling pathway on epithelial-mesenchymal transition (EMT) of human cutaneous melanoma cells was explored. Eighty patients with cutaneous melanoma were enrolled in the study. Cells were transfected accordingly and divided into five groups: The blank group (human cutaneous melanoma cells), NC group (human cutaneous melanoma cells + blank vector plasmid transfection), CXCL8 siRNA group (human cutaneous melanoma cells + CXCL8 silent expression vector plasmid transfection), AG490 group (human cutaneous melanoma cells + JAK-STAT signal pathway inhibitor transfection), CXCL8 siRNA + AG490 group (human cutaneous melanoma cells + JAK-STAT signaling pathway inhibitor + CXCL8 silent expression vector plasmid transfection). The expression levels of CXCL8, JAK2, STAT3, epithelial cadherin (E-cadherin), neurotrophic cadherin (N-cadherin) and vimentin in tissues and cells were detected by RT-qPCR and western blot analysis. CCK-8 and flow cytometry were used to detect cell proliferation and apoptosis. Compared with adjacent normal tissues, the expression of E-cadherin in human cutaneous melanoma tissues was significantly decreased, whereas the expression of CXCL8, JAK2, STAT3, vimentin and N-cadherin was significantly increased (P<0.05). Compared with the blank group, CXCL8 siRNA group and CXCL8 siRNA + AG490 group had significantly lower expression of CXCL8 (P<0.05). Compared with the blank group, the expression levels of JAK2, STAT3, vimentin and N-cadherin in CXCL8 siRNA group, AG490 group and CXCL8 siRNA + AG490 group were decreased, the expression of E-cadherin was increased, the cell proliferation ability was decreased and apoptosis was increased (P<0.05). Compared with CXCL8 siRNA group, the expression of JAK2, STAT3, vimentin and N-cadherin in CXCL8 siRNA + AG490 group were significantly decreased, the expression of E-cadherin was significantly increased, cell proliferation ability was decreased and apoptosis was increased (P<0.05). In conclusion, CXCL8 gene expression silencing may inhibit EMT and cell proliferation while promoting cell apoptosis of human cutaneous melanoma cells by inhibiting the activation of JAK-STAT signaling pathway.

Knockdown of long non-coding RNA HOTAIR reverses cisplatin resistance of ovarian cancer cells through inhibiting miR-138-5p-regulated EZH2 and SIRT1

Background

Cisplatin resistance (DDP-resistance) remains one of the major causes of poor prognosis in females with ovarian cancer. Long non-coding RNAs (lncRNAs) have been shown to participate in the regulation of cellular processes, including chemoresistance. The aim of this study was to explore the role of HOX transcript antisense RNA (HOTAIR) in DDP-resistant ovarian cancer cells.

Methods

DDP-resistant ovarian cancer cell lines (SKOV3/DDP and A2780/DDP) were established. Real-time PCR, western blot, dual-luciferase reporter assay, and flow cytometry were then used to evaluate the effect of HOTAIR/miR-138-5p axis on chemoresistance of DDP-resistant ovarian cancer cells to DDP.

Results

We found that HOTAIR was upregulated in DDP-resistant cells, while miR-138-5p was downregulated. Knockdown of HOTAIR increased the expression of miR-138-5p in DDP-resistant cells and miR-138-5p is directly bound to HOTAIR. Upregulation of miR-138-5p induced by HOTAIR siRNA or by its mimics enhanced the chemosensitivity of DDP-resistant cells and decreased the expression of EZH2 (enhancer of zeste 2 polycomb repressive complex 2 subunit) and SIRT1 (sirtuin 1). Furthermore, the HOTAIR silencing-induced chemosensitivity of DDP-resistant cells was weakened by miR-138-5p inhibitor.

Conclusions

These data demonstrate that HOTAIR acts as a sponge of miR-138-5p to prevent its binding to EZH2 and SIRT1, thereby promoting DDP-resistance of ovarian cancer cells. Our work will shed light on the development of therapeutic strategies for ovarian cancer treatment.

Long non-coding RNA HOTAIR knockdown enhances radiosensitivity through regulating microRNA-93/ATG12 axis in colorectal cancer

Colorectal cancer (CRC) is a global healthcare problem. Radioresistance is a huge setback for CRC radiotherapy. In this text, the roles and molecular mechanisms of long non-coding RNA HOTAIR in CRC tumorigenesis and radioresistance were further investigated. ATG12 mRNA, HOTAIR, and microRNA-93 (miR-93) levels were measured by quantitative reverse transcription polymerase chain reaction (RT-qPCR) assay. Protein levels of LC3 I, LC3 II, p62, ATG12, cleaved caspase 3, Bax, and Bcl-2 were detected by western blotting assay in cells and were examined by immunohistochemistry (IHC) assay in tissues. Cell survival fractions, viability, and apoptotic rates were determined by clonogenic survival assay, CCK-8 assay, and flow cytometry analysis, respectively. The relationships of HOTAIR, miR-93, and ATG12 were tested by bioinformatics analysis and luciferase reporter assay. Mouse xenograft tumor models were established to investigate the influence of HOTAIR knockdown on CRC radioresistance in vivo. We found that HOTAIR expression was markedly upregulated in plasma from CRC patients after radiotherapy and CRC cells after irradiation. HOTAIR knockdown, miR-93 overexpression, or ATG12 silencing weakened cell viability, induced cell apoptosis, inhibited cell autophagy, and enhanced cell radiosensitivity in CRC. HOTAIR exerted its functions by downregulating miR-93. Moreover, HOTAIR functioned as a molecular sponge of miR-93 to regulate ATG12 expression. ATG12 protein expression was markedly upregulated and associated with miR-93 and HOTAIR expression in CRC tissues. Furthermore, HOTAIR knockdown enhanced radiosensitivity of CRC xenograft tumors by regulating miR-93/ATG12 axis. In conclusion, HOTAIR knockdown potentiated radiosensitivity through regulating miR-93/ATG12 axis in CRC, further elucidating the roles and molecular basis of HOTAIR in CRC radioresistance.

MicroRNAs as major regulators of the autophagy pathway

Autophagy is a cellular stress response mechanism activation of which leads to degradation of cellular components, including proteins as well as damaged organelles in lysosomes. Defects in autophagy mechanisms were associated with several pathologies (e.g. cancer, neurodegenerative diseases, and rare genetic diseases). Therefore, autophagy regulation is under strict control. Transcriptional and post-translational mechanisms that control autophagy in cells and organisms studied in detail. Recent studies introduced non-coding small RNAs, and especially microRNAs (miRNAs) in the post-translational orchestration of the autophagic activity. In this review article, we analyzed in detail the current status of autophagy-miRNA connections. Comprehensive documentation of miRNAs that were directly involved in autophagy regulation resulted in the emergence of common themes and concepts governing these complex and intricate interactions. Hence, a better and systematic understanding of these interactions reveals a central role for miRNAs in the regulation of autophagy.