Human colorectal cancer-specific CCAT1-L lncRNA regulates long-range chromatin interactions at the MYC locus. Cell Res. 2014;24:513-531. [PMID: 24662484 PMCID: PMC4011346 DOI: 10.1038/cr.2014.35]

Tumor-associated long non-coding RNAs show variable expression across diffuse gliomas and effect on cell growth upon silencing in glioblastoma

Long noncoding RNAs (lncRNAs) have been recently recognized as critical components of cancer biology linked to oncogenic processes. Certain lncRNAs are known to act as oncogenes, and the disease-specific expression of many lncRNAs makes them informative biomarkers. We identified 22 uncharacterized lncRNAs from RNA-seq data of 169 glioblastoma (GBM) tumor samples sequenced by The Cancer Genome Atlas (TCGA) consortium and studied their expression in TCGA diffuse glioma cohort including also IDH-mutant astrocytomas and oligodendrogliomas as well as in normal brain samples from the Genotype-Tissue Expression cohort. All of the 22 lncRNAs were clearly upregulated in diffuse gliomas samples compared to the normal brain. Interestingly, 20 (91%) of these lncRNAs had significant expression differences between tumor grades and/or entities, and 14 (64%) were associated with overall patient survival. All 22 lncRNAs were expressed in at least one of the studied GBM cell lines and 10 (45%) were expressed in all four. When six of the lncRNAs were silenced in the SNB19 GBM cell line, the knock-down was associated with reduced growth and colony formation for three lncRNAs: TCONS_l2_00001282, lnc-GBMT-6, and lnc-NBN-1. In conclusion, the studied lncRNAs are associated with survival in patients with diffuse glioma and have functional relevance in GBM.

The roles of enhancer, especially super-enhancer-driven genes in tumor metabolism and immunity

Abnormal metabolism is a characteristic of malignant tumors. Numerous factors play roles in the regulation of tumor metabolism. As epigenetic regulators, enhancers, especially the super-enhancers (SEs), serve as platforms for transcription factors that regulate the expression of metabolism-related enzymes or transporters at the gene level. In this study, we review the effects of enhancer/ SE-driven genes on tumor metabolism and immunity. Enhancers/SEs play regulatory roles in glucose metabolism (glycolysis, gluconeogenesis, tricarboxylic acid (TCA) cycle, pyruvate, and pentose phosphate pathway, lipid metabolism (cholesterol, fatty acid, phosphatide, and sphingolipid), and amino acid metabolism (glutamine, tryptophan, arginine, and cystine). By regulating tumor metabolism, enhancers and SEs can reprogram tumor microenvironment, especially the status of various immune cells. Therefore, interfering enhancers/SEs that regulate the tumor metabolism is likely to enhance the effectiveness of immunotherapy.

Biomolecules Interacting with Long Noncoding RNAs

This review explores the complex interactions between long noncoding RNAs (lncRNAs) and other biomolecules, highlighting their pivotal roles in gene regulation and cellular function. LncRNAs, defined as RNA transcripts exceeding 200 nucleotides without encoding proteins, are involved in diverse biological processes, from embryogenesis to pathogenesis. They interact with DNA through mechanisms like triplex structure formation, influencing chromatin organization and gene expression. LncRNAs also modulate RNA-mediated processes, including mRNA stability, translational control, and splicing regulation. Their versatility stems from their forming of complex structures that enable interactions with various biomolecules. This review synthesizes current knowledge on lncRNA functions, discusses emerging roles in development and disease, and evaluates potential applications in diagnostics and therapeutics. By examining lncRNA interactions, it provides insights into the intricate regulatory networks governing cellular processes, underscoring the importance of lncRNAs in molecular biology. Unlike the majority of previous reviews that primarily focused on individual aspects of lncRNA biology, this comprehensive review uniquely integrates structural, functional, and mechanistic perspectives on lncRNA interactions across diverse biomolecules. Additionally, this review critically evaluates cutting-edge methodologies for studying lncRNA interactions, bridges fundamental molecular mechanisms with potential clinical applications, and highlights their potential.

A specific pluripotency-associated eRNA controls Nanog locus by shaping the epigenetic landscape and stabilizing enhancer-promoter interaction

Despite a plethora of studies exploring the transcriptional regulation of the Nanog gene, the role of the enhancer RNAs (eRNAs) derived from Nanog-interacting super-enhancers (SEs) remains under-investigated. In the present study, we examined the functional role of the eRNAs transcribed from the -5 kb Nanog SE in mouse embryonic stem cells (mESCs) and found that an eRNA, here defined as -5KNAR, was essential to maintain the Nanog locus in an epigenetically active configuration, thereby ensuring pluripotency. We found that the here identified -5KNAR functionally interacts with the RAD21 protein, suggesting a role in stabilizing a cohesin complex at the Nanog locus, ensuring the generation and maintenance of an enhancer-promoter loop. Silencing of -5KNAR caused a cascade of events, including the generation of a DNA methylation wave (likely spreading from a single methylated CpG site), substantial chromatin remodeling, and loss of the enhancer-promoter loop, inducing Nanog silencing and mESC differentiation. Under these conditions, exogenous re-expression of Nanog was unable to restore either the endogenous Nanog expression or the enhancer-promoter interaction, suggesting that, at hierarchical level, the expression of the -5KNAR plays a prominent role in maintaining the pluripotency in mESCs.

A transcription coupling model for how enhancers communicate with their target genes

How enhancers communicate with their target genes to influence transcription is an unresolved question of fundamental importance. Current models of the mechanism of enhancer-target gene or enhancer-promoter (E-P) communication are transcription-factor-centric and underappreciate major findings, including that enhancers are themselves transcribed by RNA polymerase II, which correlates with enhancer activity. In this Perspective, we posit that enhancer transcription and its products, enhancer RNAs, are elementary components of enhancer-gene communication. Specifically, we discuss the possibility that transcription at enhancers and at their cognate genes are linked and that this coupling is at the basis of how enhancers communicate with their targets. This model of transcriptional coupling between enhancers and their target genes is supported by growing experimental evidence and represents a synthesis of recent key discoveries.

An ensemble learning method combined with multiple feature representation strategies to predict lncRNA subcellular localizations

Long non-coding RNAs (lncRNAs) are strongly associated with cellular physiological mechanisms and implicated in the numerous diseases. By exploring the subcellular localizations of lncRNAs, we can not only gain crucial insights into the molecular mechanisms of lncRNA-related biological processes but also make valuable contributions towards the diagnosis, prevention, and treatment of various human diseases. However, conventional experimental techniques tend to be laborious and time-intensive. In this context, computational methods are in increased demand. The focus of this paper is the development of an innovative ensemble method that incorporates hybrid features to accurately predict the subcellular localizations of lncRNAs. To address the issue of incomplete reflection of inherent correlation with the intended target using singular source features, the utilization of heterogeneous multi-source features is implemented by introducing information on sequence composition, physicochemical properties, and structure. To address the issue of the imbalance classes in the benchmark dataset, the Synthetic Minority Over-sampling Technique (SMOTE) is employed. Finally, the resulting predictor termed lncSLPre is developed by integrating the outputs of the individual classifiers. Experimental findings suggest that the complementarity of multi-source heterogeneous features improves prediction performance. Additionally, it is demonstrated that the application of SMOTE is effective in mitigating the issue of the imbalanced dataset, while the feature selection approach is critical in eliminating extraneous and redundant features. Compared with existing advanced methods, lncSLPre achieves better performance with an overall accuracy improvement of 13.13%, 2.15%, and 3.23%, respectively, indicating that lncSLPre can effectively predict lncRNA subcellular localizations.

The LncRNA lnc-POTEM-4:14 promotes HCC progression by interacting with FOXK1

Hepatocellular carcinoma (HCC) is one of the most common malignant tumours of the digestive tract and poses a serious threat to human life. This study first analysed two GEO datasets (GSE166705 and GSE115018) to screen for differentially expressed lncRNAs between HCC and adjacent tissues. The lncRNA lnc-POTEM-4:14 was determined via a series of methods to be closely related to liver cancer. Further research was subsequently performed to investigate the role of the lncRNA lnc-POTEM-4:14 in the progression of HCC. The lncRNA lnc-POTEM-4:14 is localized primarily within the nucleus and is highly expressed in liver cancer tissues. We established lnc-POTEM-4:14 knockdown and overexpression cell lines to analyse the role of lnc-POTEM-4:14 in liver cancer through functional experiments such as qPCR and WB. We identified FOXK1 as an RNA-binding protein (RBP) of lnc-POTEM-4:14 that participates in MAPK signal activation and cell cycle progression by regulating the activation or expression levels of the downstream target protein TAB1 as a transcription factor. The restoration of FOXK1 can rescue the limited proliferation and increased apoptosis caused by lnc-POTEM-4:14 knockdown. Finally, we validated our hypothesis in a nude mouse tumour-bearing model. In conclusion, lnc-POTEM-4:14 affects the progression of HCC through the FOXK1/TAB1/NLK axis, suggesting that lnc-POTEM-4:14 has potential as a therapeutic target for treating this aggressive malignancy.

CASCADES, a novel SOX2 super-enhancer-associated long noncoding RNA, regulates cancer stem cell specification and differentiation in glioblastoma

Glioblastoma is the most common primary malignant brain tumor in adults, with a median survival of just over 1 year. The failure of available treatments to achieve remission in patients with glioblastoma (GBM) has been attributed to the presence of cancer stem cells (CSCs), which are thought to play a central role in tumor development and progression and serve as a treatment-resistant cell repository capable of driving tumor recurrence. In fact, the property of "stemness" itself may be responsible for treatment resistance. In this study, we identify a novel long noncoding RNA (lncRNA), cancer stem cell-associated distal enhancer of SOX2 (CASCADES), that functions as an epigenetic regulator in glioma CSCs (GSCs). CASCADES is expressed in isocitrate dehydrogenase (IDH)-wild-type GBM and is significantly enriched in GSCs. Knockdown of CASCADES in GSCs results in differentiation towards a neuronal lineage in a cell- and cancer-specific manner. Bioinformatics analysis reveals that CASCADES functions as a super-enhancer-associated lncRNA epigenetic regulator of SOX2. Our findings identify CASCADES as a critical regulator of stemness in GSCs that represents a novel epigenetic and therapeutic target for disrupting the CSC compartment in glioblastoma.

Understanding lncRNAs: key regulators of myogenesis and lipogenesis in farm animals

Long non-coding RNAs (lncRNAs) are RNA molecules exceeding 200 nucleotides in length. Recent studies have demonstrated their involvement in regulating gene expression and various biological processes. Among these, myogenesis and lipogenesis are particularly important because of their direct effects on muscle development and fat deposition in farm animals. These processes are crucial for determining meat quality, growth rates, and overall economic value in animal husbandry. Although the specific mechanisms through which lncRNAs influence these pathways are still under investigation, further research into their roles in muscle and fat development is crucial for optimizing farm animal breeding strategies. Here, we review the characteristics of lncRNAs, including their biogenesis, localization, and structures, with a particular focus on their association with myogenesis and adipogenesis. This review seeks to establish a theoretical foundation for enhancing farm animal production. In particular, focusing on lncRNAs may reveal how these molecules can enhance the economic traits of farm animals, thereby contributing to the optimization of farm animal breeding processes.

Comprehensive dissection of cis-regulatory elements in a 2.8 Mb topologically associated domain in six human cancers

Cis-regulatory elements (CREs), such as enhancers and promoters, are fundamental regulators of gene expression and, across different cell types, the MYC locus utilizes a diverse regulatory architecture driven by multiple CREs. To better understand differences in CRE function, we perform pooled CRISPR inhibition (CRISPRi) screens to comprehensively probe the 2.8 Mb topologically-associated domain containing MYC in 6 human cancer cell lines with nucleotide resolution. We map 32 CREs where inhibition leads to changes in cell growth, including 8 that overlap previously identified enhancers. Targeting specific CREs decreases MYC expression by as much as 60%, and cell growth by as much as 50%. Using 3-D enhancer contact mapping, we find that these CREs almost always contact MYC but less than 10% of total MYC contacts impact growth when silenced, highlighting the utility of our approach to identify phenotypically-relevant CREs. We also detect an enrichment of lineage-specific transcription factors (TFs) at MYC CREs and, for some of these TFs, find a strong, tumor-specific correlation between TF and MYC expression not found in normal tissue. Taken together, these CREs represent systematically identified, functional regulatory regions and demonstrate how the same region of the human genome can give rise to complex, tissue-specific gene regulation.

Non-Coding RNAs in Cancer: Structure, Function, and Clinical Application

We are on the brink of a paradigm shift in both theoretical and clinical oncology. Genomic and transcriptomic profiling, alongside personalized approaches that account for individual patient variability, are increasingly shaping discourse. Discussions on the future of personalized cancer medicine are mainly dominated by the potential of non-coding RNAs (ncRNAs), which play a prominent role in cancer progression and metastasis formation by regulating the expression of oncogenic or tumor suppressor proteins at transcriptional and post-transcriptional levels; furthermore, their cell-free counterparts might be involved in intercellular communication. Non-coding RNAs are considered to be promising biomarker candidates for early diagnosis of cancer as well as potential therapeutic agents. This review aims to provide clarity amidst the vast body of literature by focusing on diverse species of ncRNAs, exploring the structure, origin, function, and potential clinical applications of miRNAs, siRNAs, lncRNAs, circRNAs, snRNAs, snoRNAs, eRNAs, paRNAs, YRNAs, vtRNAs, and piRNAs. We discuss molecular methods used for their detection or functional studies both in vitro and in vivo. We also address the challenges that must be overcome to enter a new era of cancer diagnosis and therapy that will reshape the future of oncology.

Unveiling the hidden gem: A review of long non-coding RNA NBAT-1 as an emerging tumor suppressor and prognostic biomarker in cancer

Previously considered junk or non-functional, long non-coding RNAs (lncRNAs) have emerged over the past few decades as pivotal components in both physiological and pathological processes, including cancer. Neuroblastoma-associated transcript-1 (NBAT-1) was initially discovered a decade ago as a risk-associated tumor suppressor lncRNA in neuroblastoma (NB). Subsequent studies have consistently demonstrated that NBAT-1 serves as a dedicated tumor suppressor in many cancers. NBAT-1 is significantly downregulated in cancer, which is closely linked to higher histological grades, increased metastasis, and poor survival in cancer patients suggesting NBAT-1's potential as a prognostic biomarker. In this review, we delve into the current body of literature, elucidating the tumor-suppressive roles of NBAT-1 and the underlying regulatory mechanisms in the context of human malignancies. Additionally, we shed light on the mechanisms contributing to the diminished expression of NBAT-1 and its potential as both a prognostic biomarker and a promising therapeutic target in cancer.

Super-enhancer-driven SLCO4A1-AS1 is a new biomarker and a promising therapeutic target in glioblastoma

Glioblastoma (GBM) is the most common intracranial malignancy, but current treatment options are limited. Super-enhancers (SEs) have been found to drive the expression of key oncogenes in GBM. However, the role of SE-associated long non-coding RNAs (lncRNAs) in GBM remains poorly understood. Here, we screened for an up-regulated lncRNA-SLCO4A1-AS1 expressed in GBM by analyzing data from GSE54791, GSE4536 and TCGA. We systematically analyzed its relationship with clinical characteristics, prognosis, epigenetics, tumor microenvironment (TME), biological functions, and transcription factors. We found that SE-driven SLCO4A1-AS1 was significantly upregulated in GBM and correlated with poor prognosis. Knockdown of SLCO4A1-AS1 decreased glioma cell proliferation, invasive ability, self-renewal ability, and increased apoptosis. Epigenetic analysis revealed that SOX2 and SE could drive SLCO4A1-AS1 expression. In vitro experiments further demonstrated that GBM cells with high SLCO4A1-AS1 expression were more sensitive to VX-11e, and overexpression of SLCO4A1-AS1 could reverse the inhibitory effect of VX-11e on GBM cells. In conclusion, this study revealed that SE-driven SLCO4A1-AS1 may be a potential therapeutic target in GBM.

Discovering the interactome, functions, and clinical relevance of enhancer RNAs in kidney renal clear cell carcinoma

Enhancer RNA (eRNA) has emerged as a key player in cancer biology, influencing various aspects of tumor development and progression. In this study, we investigated the role of eRNAs in kidney renal clear cell carcinoma (KIRC), the most common subtype of renal cell carcinoma. Leveraging high-throughput sequencing data and bioinformatics analysis, we identified differentially expressed eRNAs in KIRC and constructed eRNA-centric regulatory networks. Our findings revealed that up-regulated eRNAs in KIRC potentially regulate immune response and hypoxia pathways, while down-regulated eRNAs may impact ion transport, cell cycle, and metabolism. Furthermore, we developed a diagnostic prediction model based on eRNA expression profiles, demonstrating its effectiveness in KIRC diagnosis. Finally, we elucidated the regulatory mechanism of an eRNA (ENSR00000305834) on the expression of SLC15A2, a potential prognostic biomarker in KIRC, through bioinformatics analysis and in vitro validation experiments. In summary, Our study highlights the clinical significance of eRNAs in KIRC and underscores their potential as therapeutic targets.

DNA regulatory element cooperation and competition in transcription

Regulation of eukaryotic transcription is a complex process that enables precise temporal and spatial control of gene expression. Promoters, which are cis-regulatory elements (CREs) located proximal to the transcription start site (TSS), selectively integrate regulatory cues from distal CREs, or enhancers, and their associated transcriptional machinery. In this review, we discuss current knowledge regarding CRE cooperation and competition impacting gene expression, including features of enhancer-promoter, enhancer-enhancer, and promoter-promoter interplay. We also provide an overview of recent insights into the underlying molecular mechanisms that facilitate physical and functional interaction of regulatory elements, such as the involvement of enhancer RNAs and biomolecular condensates. [BMB Reports 2024; 57(12): 509-520].

The implications for urological malignancies of non-coding RNAs in the the tumor microenvironment

Urological malignancies are a major global health issue because of their complexity and the wide range of ways they affect patients. There's a growing need for in-depth research into these cancers, especially at the molecular level. Recent studies have highlighted the importance of non-coding RNAs (ncRNAs) – these don't code for proteins but are crucial in controlling genes – and the tumor microenvironment (TME), which is no longer seen as just a background factor but as an active player in cancer progression. Understanding how ncRNAs and the TME interact is key for finding new ways to diagnose and predict outcomes in urological cancers, and for developing new treatments. This article reviews the basic features of ncRNAs and goes into detail about their various roles in the TME, focusing specifically on how different ncRNAs function and act in urological malignancies.

SE-lncRNAs in Cancer: Classification, Subcellular Localisation, Function and Corresponding TFs

Emerging evidence highlights certain long noncoding RNAs (lncRNAs) transcribed from or interacting with super-enhancer (SE) regulatory elements. These lncRNAs, known as SE-lncRNAs, are strongly linked to cancer and regulate cancer progression through multiple interactions with downstream targets. The expression of SE-lncRNAs is controlled by various transcription factors (TFs), and dysregulation of these TFs can contribute to cancer development. In this review, we discuss the characteristics, classification and subcellular distribution of SE-lncRNAs and summarise the role of key TFs in the transcription and regulation of SE-lncRNAs. Moreover, we examine the distinct functions and potential mechanisms of SE-lncRNAs in cancer progression.

Role of long non-coding RNAs in neurofibromatosis and Schwannomatosis: pathogenesis and therapeutic potential

Neurofibromatosis (NF) is identified as genetic disorder characterized by multiple tumors on nerve tissues. NF1 is the most prevalent form, identified by neurofibromas and skin changes. NF1 is the most prevalent neurofibromatosis disorder, distinct from the rarer NF2 and schwannomatosis (SWN) conditions. NF2, including NF2-related SWN (NF2-SWN), predominantly involves schwannoma formation and differs from NF1 in its genetic basis and clinical presentation. Despite the established genetic basis of NF, effective treatments remain scarce. Long non-coding RNAs (lncRNAs) have emerged as important regulators of gene expression, impacting pathways vital to tumor biology. This review explores the lncRNAs role in NF pathogenesis along with their potential as therapeutic targets. LncRNAs such as ANRIL and H19 show dysregulated expression in NF, influencing signaling pathways like Ras/MAPK and JAK/STAT, thereby contributing to tumor development. Understanding these interactions sheds light on the molecular mechanisms underlying NF and highlights lncRNAs as potential biomarkers of diagnosis and prognosis of NF. Additionally, therapeutic strategies targeting lncRNAs with antisense oligonucleotides (ASOs) or CRISPR-Cas9 offer promising treatment options. The present review emphasizes crucial role of lncRNAs in NF pathogenesis and their promise to create innovative treatments, aiming to improve patient outcomes and meet the urgent need for effective NF therapies.

Diagnostics and Therapy for Malignant Tumors

Malignant tumors remain one of the most significant global health challenges and contribute to high mortality rates across various cancer types. The complex nature of these tumors requires multifaceted diagnostic and therapeutic approaches. This review explores current advancements in diagnostic methods, including molecular imaging, biomarkers, and liquid biopsies. It also delves into the evolution of therapeutic strategies, including surgery, chemotherapy, radiation therapy, and novel targeted therapies such as immunotherapy and gene therapy. Although significant progress has been made in the understanding of cancer biology, the future of oncology lies in the integration of precision medicine, improved diagnostic tools, and personalized therapeutic approaches that address tumor heterogeneity. This review aims to provide a comprehensive overview of the current state of cancer diagnostics and treatments while highlighting emerging trends and challenges that lie ahead.

Comprehensive review of LncRNA-mediated therapeutic resistance in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) are emerging as crucial regulators of gene expression through diverse mechanisms, including regulation of protein localization, sequestration of miRNAs, recruitment of chromatin modifiers, and modulation of signaling pathways. Accumulating evidence highlights their pivotal roles in tumor initiation, progression, and the development of therapeutic resistance. In this review, we comprehensively summarized the existing literature to identify lncRNAs associated with treatment responses in non-small cell lung cancer (NSCLC). Specifically, we categorized these lncRNAs based on their mechanisms of action in mediating resistance to chemotherapy, targeted therapy, and radiotherapy. Our analysis revealed that aberrant expression of various lncRNAs contributes to the development, metastasis, and therapeutic resistance in NSCLC, ultimately leading to poor clinical outcomes. By elucidating the intricate mechanisms through which lncRNAs modulate therapeutic responses, this review aims to provide mechanistic insights into the heterogeneous treatment outcomes observed in NSCLC patients and unveil potential therapeutic targets for overcoming drug resistance.

Long non-coding RNAs: regulators of autophagy and potential biomarkers in therapy resistance and urological cancers

The non-coding RNAs (ncRNAs) comprise a large part of human genome that mainly do not code for proteins. Although ncRNAs were first believed to be non-functional, the more investigations highlighted tthe possibility of ncRNAs in controlling vital biological processes. The length of long non-coding RNAs (lncRNAs) exceeds 200 nucleotidesand can be present in nucleus and cytoplasm. LncRNAs do not translate to proteins and they have been implicated in the regulation of tumorigenesis. On the other hand, One way cells die is by a process called autophagy, which breaks down proteins and other components in the cytoplasm., while the aberrant activation of autophagy allegedly involved in the pathogenesis of diseases. The autophagy exerts anti-cancer activity in pre-cancerous lesions, while it has oncogenic function in advanced stages of cancers. The current overview focuses on the connection between lncRNAs and autophagy in urological cancers is discussed. Notably, one possible role for lncRNAs is as diagnostic and prognostic variablesin urological cancers. The proliferation, metastasis, apoptosis and therapy response in prostate, bladder and renal cancers are regulated by lncRNAs. The changes in autophagy levels can also influence the apoptosis, proliferation and therapy response in urological tumors. Since lncRNAs have modulatory functions, they can affect autophagy mechanism to determine progression of urological cancers.

Superenhancer-driven circRNA Myst4 involves in pulmonary artery smooth muscle cell ferroptosis in pulmonary hypertension

The abnormal expression of circular RNAs (circRNAs) is emerging as a critical cause in regulation of pathological changes of hypoxic pulmonary hypertension (PH), in which ferroptosis is a new pathological change reported recently. However, how circRNAs regulate ferroptosis remains unclear. Here, we proved a significant decrease in circMyst4 expression in hypoxia. In vitro assays revealed that circMyst4 alleviated hypoxic pulmonary artery smooth muscle cell (PASMC) ferroptosis through directly combing with DDX5 in the nucleus to promote GPX4 mRNA processing and inhibiting the formation of the Eef1a1/ACSL4 complex in the cytoplasm. Additionally, superenhancer (SE) was verified to drive the generation of circMyst4. In vivo assays revealed that circMyst4 inhibited the progression of hypoxic PH. Overall, SE-driven circMyst4 may be a new potential therapeutic target for mediating PASMC ferroptosis through promoting DDX5-regulated GPX4 mRNA processing and inhibiting the binding between Eef1a1 and ACSL4.

Discovery of prognostic lncRNAs in colorectal cancer using spatial transcriptomics

Colorectal cancer (CRC) exhibits significant genetic and epigenetic diversity, evolving into sub-clonal populations with varied metastatic potentials and treatment responses. Predicting metastatic disease in CRC patients remains challenging, underscoring the need for reliable biomarkers. While most research on therapeutic targets and biomarkers has focused on proteins, non-coding RNAs such as long non-coding RNAs (lncRNAs) comprise most of the transcriptome and demonstrate superior tissue- and cancer-specific expression. We utilised spatial transcriptomics to investigate lncRNAs in CRC tumours, offering more precise cell-type-specific expression data compared to bulk RNA sequencing. Our analysis identified 301 lncRNAs linked to malignant CRC regions, which we validated with public data. Further validation using RNA-FISH revealed three lncRNAs (LINC01978, PLAC4, and LINC01303) that are detectable in stage II tumours but not in normal epithelium and are upregulated in metastatic tissues. These lncRNAs hold potential as biomarkers for early risk assessment of metastatic disease.

Connecting the dots: LncRNAs in the KRAS pathway and cancer

Long non-coding RNAs (lncRNAs) have been identified as important participants in several biological functions, particularly their complex interactions with the KRAS pathway, which provide insights into the significant roles lncRNAs play in cancer development. The KRAS pathway, a central signaling cascade crucial for cell proliferation, survival, and differentiation, stands out as a key therapeutic target due to its aberrant activation in many human cancers. Recent investigations have unveiled a myriad of lncRNAs, such as H19, ANRIL, and MEG3, intricately modulating the KRAS pathway, influencing both its activation and repression through various mechanisms, including epigenetic modifications, transcriptional regulation, and post-transcriptional control. These lncRNAs function as fine-tuners, delicately orchestrating the balance required for normal cellular function. Their dysregulation has been linked to the development and progression of multiple malignancies, including lung, pancreatic, and colorectal carcinomas, which frequently harbor KRAS mutations. This scrutiny delves into the functional diversity of specific lncRNAs within the KRAS pathway, elucidating their molecular mechanisms and downstream effects on cancer phenotypes. Additionally, it underscores the diagnostic and prognostic potential of these lncRNAs as indicators for cancer detection and assessment. The complex regulatory network that lncRNAs construct within the context of the KRAS pathway offers important insights for the creation of focused therapeutic approaches, opening new possibilities for precision medicine in oncology. However, challenges such as the dual roles of lncRNAs in different cancer types and the difficulty in therapeutically targeting these molecules highlight the ongoing debates and need for further research. As ongoing studies unveil the complexities of lncRNA-mediated KRAS pathway modulation, the potential for innovative cancer interventions becomes increasingly promising.

Unraveling the ncRNA landscape that governs colorectal cancer: A roadmap to personalized therapeutics

Colorectal cancer (CRC) being one of the most common malignancies, has a significant death rate, especially when detected at an advanced stage. In most cases, the fundamental aetiology of CRC remains unclear despite the identification of several environmental and intrinsic risk factors. Numerous investigations, particularly in the last ten years, have indicated the involvement of epigenetic variables in this type of cancer. The development, progression, and metastasis of CRC are influenced by long non-coding RNAs (lncRNAs), which are significant players in the epigenetic pathways. LncRNAs are implicated in diverse pathological processes in CRC, such as liver metastasis, epithelial to mesenchymal transition (EMT), inflammation, and chemo-/radioresistance. It has recently been determined that CRC cells and tissues exhibit dysregulation of tens of oncogenic and tumor suppressor lncRNAs. Serum samples from CRC patients exhibit dysregulated expressions of several of these transcripts, offering a non-invasive method of detecting this kind of cancer. In this review, we outlined the typical paradigms of the deregulated lncRNA which exert significant role in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the role of lncRNAs as innovative targets for CRC prognosis and treatment.

Long non‑coding RNAs as diagnostic and prognostic biomarkers for colorectal cancer (Review)

Colorectal cancer (CRC) ranks as the 3rd most common cancer globally and is the 2nd leading cause of cancer-related death. Owing to the lack of specific early symptoms and the limitations of existing early diagnostic methods, most patients with CRC are diagnosed at advanced stages. To overcome these challenges, researchers have increasingly focused on molecular biomarkers, with particular interest in long non-coding RNAs (lncRNAs). These non-protein-coding RNAs, which exceed 200 nucleotides in length, play critical roles in the development and progression of CRC. The stability and detectability of lncRNAs in the circulatory system make them promising candidate biomarkers. The analysis of circulating lncRNAs in peripheral blood represents a potential option for minimally invasive diagnostic tests based on liquid biopsy samples. The present review aimed to evaluate the efficacy of lncRNAs with altered expression levels in peripheral blood as diagnostic markers for CRC. Additionally, the clinical significance of lncRNAs as prognostic markers for this disease were summarized.

The enhancer RNA, AANCR, regulates APOE expression in astrocytes and microglia

Enhancers, critical regulatory elements within the human genome, are often transcribed into enhancer RNAs. The dysregulation of enhancers leads to diseases collectively termed enhanceropathies. While it is known that enhancers play a role in diseases by regulating gene expression, the specific mechanisms by which individual enhancers cause diseases are not well understood. Studies of individual enhancers are needed to fill this gap. This study delves into the role of APOE-activating noncoding RNA, AANCR, in the central nervous system, elucidating its function as a genetic modifier in Alzheimer's Disease. We employed RNA interference, RNaseH-mediated degradation, and single-molecule RNA fluorescence in situ hybridization to demonstrate that mere transcription of AANCR is insufficient; rather, its transcripts are crucial for promoting APOE expression. Our findings revealed that AANCR is induced by ATM-mediated ERK phosphorylation and subsequent AP-1 transcription factor activation. Once activated, AANCR enhances APOE expression, which in turn imparts an inflammatory phenotype to astrocytes. These findings demonstrate that AANCR is a key enhancer RNA in some cell types within the nervous system, pivotal for regulating APOE expression and influencing inflammatory responses, underscoring its potential as a therapeutic target in neurodegenerative diseases.

Unraveling the Regulatory Role of HuR/microRNA Axis in Colorectal Cancer Tumorigenesis

Colorectal cancer (CRC) remains a significant global health burden with high incidence and mortality. MicroRNAs (miRNAs) are small non-protein coding transcripts, conserved throughout evolution, with an important role in CRC tumorigenesis, and are either upregulated or downregulated in various cancers. RNA-binding proteins (RBPs) are known as essential regulators of miRNA activity. Human antigen R (HuR) is a prominent RBP known to drive tumorigenesis with a pivotal role in CRC. In this review, we discuss the regulatory role of the HuR/miRNA axis in CRC. Interestingly, miRNAs can directly target HuR, altering its expression and activity. However, HuR can also stabilize or degrade miRNAs, forming complex feedback loops that either activate or block CRC-associated signaling pathways. Dysregulation of the HuR/miRNA axis contributes to CRC initiation and progression. Additionally, HuR-miRNA regulation by other small non-coding RNAs, circular RNA (circRNAs), or long-non-coding RNAs (lncRNAs) is also explored here. Understanding this HuR-miRNA interplay could reveal novel biomarkers with better diagnostic or prognostic accuracy.

CRISPR-array-mediated imaging of non-repetitive and multiplex genomic loci in living cells

Dynamic imaging of genomic loci is key for understanding gene regulation, but methods for imaging genomes, in particular non-repetitive DNAs, are limited. We developed CRISPRdelight, a DNA-labeling system based on endonuclease-deficient CRISPR-Cas12a (dCas12a), with an engineered CRISPR array to track DNA location and motion. CRISPRdelight enables robust imaging of all examined 12 non-repetitive genomic loci in different cell lines. We revealed the confined movement of the CCAT1 locus (chr8q24) at the nuclear periphery for repressed expression and active motion in the interior nucleus for transcription. We uncovered the selective repositioning of HSP gene loci to nuclear speckles, including a remarkable relocation of HSPH1 (chr13q12) for elevated transcription during stresses. Combining CRISPR-dCas12a and RNA aptamers allowed multiplex imaging of four types of satellite DNA loci with a single array, revealing their spatial proximity to the nucleolus-associated domain. CRISPRdelight is a user-friendly and robust system for imaging and tracking genomic dynamics and regulation.

Long non-coding RNA LIP interacts with PARP-1 influencing the efficiency of base excision repair

In recent years, various long non-coding RNAs (lncRNAs) involved in DNA damage response (DDR) have been identified and studied to deepen our understanding. However, there are rare reports on the association between lncRNAs and base excision repair (BER). Our designed DNA microarray identified dozens of functionally unknown lncRNAs, and their transcription levels significantly increased upon exposure to DNA damage inducers. One of them, named LIP (Long noncoding RNA Interacts with PARP-1), exhibited a significant alteration in transcription in response to methyl methanesulfonate (MMS) and temozolomide (TMZ) treatments. LIP knockdown or knockout cell lines are sensitive to MMS and TMZ, indicating that LIP plays a crucial role in DDR. The loss or insufficiency of LIP significantly influences the efficiency of BER in human cells, and it suggests that LIP participates in the BER pathway. The interaction between LIP and a key factor in BER, poly (ADP-ribose) polymerase 1 (PARP-1), has been confirmed. We identified and characterized LIP, a lncRNA, which is involved in DDR, significantly influences BER efficiency, and interacts with the BER key factor PARP-1. This advances our understanding of the connection between lncRNAs and BER, presenting the potential for the discovery of new drug targets.

CircNAP1L4 regulates pulmonary artery smooth muscle cell proliferation via the NAP1L4-mediated super-enhancer-driven glycolysis gene hexokinase II (HK II) in pulmonary hypertension

Glycolysis is a major determinant of pulmonary artery smooth muscle cell (PASMC) proliferation in pulmonary hypertension (PH). Circular RNAs (circRNAs) are powerful regulators of glycolysis in multiple diseases; however, the role of circRNAs in glycolysis in PH has been poorly characterized. The aim of this study was to uncover the regulatory mechanism of a new circRNA, circNAP1L4, in human pulmonary artery smooth muscle cell (HPASMC) proliferation through the host protein NAP1L4 to regulate the super-enhancer-driven glycolysis gene hexokinase II (HK II). CircNAP1L4 was downregulated in hypoxic HPASMCs and plasma of PH patients. Functionally, circNAP1L4 overexpression inhibited glycolysis and proliferation in hypoxic HPASMCs. Mechanistically, circNAP1L4 directly bound to its host protein NAP1L4 and affected the ability of NAP1L4 to move into the nucleus to regulate the epigenomic signals of the super-enhancer of HK II. Intriguingly, circNAP1L4 overexpression inhibited the proliferation but not the migration of human pulmonary arterial endothelial cells (HPAECs) cocultured with HPASMCs. Furthermore, pre-mRNA-processing-splicing Factor 8 (PRP8) was found to regulate the production ratio of circNAP1L4 and linear NAP1L4. In vivo, targeting circNAP1L4 alleviates SU5416 combined with hypoxia (SuHx)-induced PH. Overall, these findings reveal a new circRNA that inhibits PASMC proliferation and serves as a therapeutic target for PH.

RNA-Independent Regulatory Functions of lncRNA in Complex Disease

During the metagenomics era, high-throughput sequencing efforts both in mice and humans indicate that non-coding RNAs (ncRNAs) constitute a significant fraction of the transcribed genome. During the past decades, the regulatory role of these non-coding transcripts along with their interactions with other molecules have been extensively characterized. However, the study of long non-coding RNAs (lncRNAs), an ncRNA regulatory class with transcript lengths that exceed 200 nucleotides, revealed that certain non-coding transcripts are transcriptional "by-products", while their loci exert their downstream regulatory functions through RNA-independent mechanisms. Such mechanisms include, but are not limited to, chromatin interactions and complex promoter-enhancer competition schemes that involve the underlying ncRNA locus with or without its nascent transcription, mediating significant or even exclusive roles in the regulation of downstream target genes in mammals. Interestingly, such RNA-independent mechanisms often drive pathological manifestations, including oncogenesis. In this review, we summarize selective examples of lncRNAs that regulate target genes independently of their produced transcripts.

Reciprocal interactions between lncRNAs and MYC in colorectal cancer: partners in crime

Proto-oncogenic MYC is frequently dysregulated in colorectal cancer (CRC). In the past decades, long noncoding RNAs (lncRNAs) have emerged as important regulators in cancers, acting as scaffolds, molecular decoys, post-transcriptional regulators, and others. Interestingly, lncRNAs are able to control MYC expression both at transcriptional and post-transcriptional levels. It is suggested that the reciprocal interaction of MYC and lncRNAs often occurs in CRC. MYC can affect the cell fate by promoting or inhibiting the transcription of some lncRNAs. At the same time, some lncRNAs can also affect MYC expression or transcriptional activity, and in turn decide the cell fate. In this review we summarized the current knowledge about the MYC and lncRNA axis, focusing on its mutual regulation, roles in CRC, and proposed potential therapeutic prospects for CRC treatment.

Role of long noncoding RNAs in diabetes-associated peripheral arterial disease

Diabetes mellitus (DM) is a metabolic disease that heightens the risks of many vascular complications, including peripheral arterial disease (PAD). Various types of cells, including but not limited to endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and macrophages (MΦs), play crucial roles in the pathogenesis of DM-PAD. Long non-coding RNAs (lncRNAs) are epigenetic regulators that play important roles in cellular function, and their dysregulation in DM can contribute to PAD. This review focuses on the developing field of lncRNAs and their emerging roles in linking DM and PAD. We review the studies investigating the role of lncRNAs in crucial cellular processes contributing to DM-PAD, including those in ECs, VSMCs, and MΦ. By examining the intricate molecular landscape governed by lncRNAs in these relevant cell types, we hope to shed light on the roles of lncRNAs in EC dysfunction, inflammatory responses, and vascular remodeling contributing to DM-PAD. Additionally, we provide an overview of the research approach and methodologies, from identifying disease-relevant lncRNAs to characterizing their molecular and cellular functions in the context of DM-PAD. We also discuss the potential of leveraging lncRNAs in the diagnosis and therapeutics for DM-PAD. Collectively, this review provides a summary of lncRNA-regulated cell functions contributing to DM-PAD and highlights the translational potential of leveraging lncRNA biology to tackle this increasingly prevalent and complex disease.

Long non-coding RNAs as pathophysiological regulators, therapeutic targets and novel extracellular vesicle biomarkers for the diagnosis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic relapsing disease of the gastrointestinal (GI) system that includes two groups, Crohn's disease (CD) and ulcerative colitis (UC). To cope with these two classes of IBD, the investigation of pathogenic mechanisms and the discovery of new diagnostic and therapeutic approaches are crucial. Long non-coding RNAs (lncRNAs) which are non-coding RNAs with a length of longer than 200 nucleotides have indicated significant association with the pathology of IBD and strong potential to be used as accurate biomarkers in diagnosing and predicting responses to the IBD treatment. In the current review, we aim to investigate the role of lncRNAs in the pathology and development of IBD. We first describe recent advances in research on dysregulated lncRNAs in the pathogenesis of IBD from the perspective of epithelial barrier function, intestinal immunity, mitochondrial function, and intestinal autophagy. Then, we highlight the possible translational role of lncRNAs as therapeutic targets, diagnostic biomarkers, and predictors of therapeutic response in colon tissues and plasma samples. Finally, we discuss the potential of extracellular vesicles and their lncRNA cargo in the pathophysiology, diagnosis, and treatment of IBD.

Chimera RNA transcribed from integrated HPV18 genome with adjacent host genomic region promotes oncogenic gene expression through condensate formation

Most cervical cancers are caused by human papillomavirus (HPV) infection. In HeLa cells, the HPV18 viral genome is integrated at chromosome 8q24.21 and activates transcription of the proto-oncogene c-Myc. However, the mechanism of how the integrated HPV genome and its transcribed RNAs exhibit transcription activation function has not been fully elucidated. In this study, we found that HPV18 transcripts contain an enhancer RNA-like function to activate proximal genes including CCAT1-5L and c-Myc. We showed that the human genome-integrated HPV18 genes are activated by transcription coregulators including BRD4 and Mediator. The transcribed HPV18 RNAs form a liquid-like condensate at chromosome 8q24.21 locus, which in turn accumulates RNA polymerase II. Moreover, we focused on a relatively uncharacterized transcript from the upstream region of CCAT1, named URC. The URC RNA is transcribed as a chimera RNA with HPV18 and is composed of the 3'-untranslated region of the HPV18 transcript. We experimentally showed that the URC contributes to stabilization of HPV18 RNAs by supplying a polyadenylation site for the HPV18 transcript. Our findings suggest that integrated HPV18 at 8q24.21 locus produces HPV18-URC chimera RNA and promotes tumorigenesis through RNA-based condensate formation.

CCAT1 lncRNA is chromatin-retained and post-transcriptionally spliced

Super-enhancers are unique gene expression regulators widely involved in cancer development. Spread over large DNA segments, they tend to be found next to oncogenes. The super-enhancer c-MYC locus forms long-range chromatin looping with nearby genes, which brings the enhancer and the genes into proximity, to promote gene activation. The colon cancer-associated transcript 1 (CCAT1) gene, which is part of the MYC locus, transcribes a lncRNA that is overexpressed in colon cancer cells through activation by MYC. Comparing different types of cancer cell lines using RNA fluorescence in situ hybridization (RNA FISH), we detected very prominent CCAT1 expression in HeLa cells, observed as several large CCAT1 nuclear foci. We found that dozens of CCAT1 transcripts accumulate on the gene locus, in addition to active transcription occurring from the gene. The accumulating transcripts are released from the chromatin during cell division. Examination of CCAT1 lncRNA expression patterns on the single-RNA level showed that unspliced CCAT1 transcripts are released from the gene into the nucleoplasm. Most of these unspliced transcripts were observed in proximity to the active gene but were not associated with nuclear speckles in which unspliced RNAs usually accumulate. At larger distances from the gene, the CCAT1 transcripts appeared spliced, implying that most CCAT1 transcripts undergo post-transcriptional splicing in the zone of the active gene. Finally, we show that unspliced CCAT1 transcripts can be detected in the cytoplasm during splicing inhibition, which suggests that there are several CCAT1 variants, spliced and unspliced, that the cell can recognize as suitable for export.

Effects of super-enhancers in cancer metastasis: mechanisms and therapeutic targets

Metastasis remains the principal cause of cancer-related lethality despite advancements in cancer treatment. Dysfunctional epigenetic alterations are crucial in the metastatic cascade. Among these, super-enhancers (SEs), emerging as new epigenetic regulators, consist of large clusters of regulatory elements that drive the high-level expression of genes essential for the oncogenic process, upon which cancer cells develop a profound dependency. These SE-driven oncogenes play an important role in regulating various facets of metastasis, including the promotion of tumor proliferation in primary and distal metastatic organs, facilitating cellular migration and invasion into the vasculature, triggering epithelial-mesenchymal transition, enhancing cancer stem cell-like properties, circumventing immune detection, and adapting to the heterogeneity of metastatic niches. This heavy reliance on SE-mediated transcription delineates a vulnerable target for therapeutic intervention in cancer cells. In this article, we review current insights into the characteristics, identification methodologies, formation, and activation mechanisms of SEs. We also elaborate the oncogenic roles and regulatory functions of SEs in the context of cancer metastasis. Ultimately, we discuss the potential of SEs as novel therapeutic targets and their implications in clinical oncology, offering insights into future directions for innovative cancer treatment strategies.

Integrated enhancer regulatory network by enhancer-promoter looping in gastric cancer

Enhancer cis-regulatory elements play critical roles in gene regulation at many stages of cell growth. Enhancers in cancer cells also regulate the transcription of oncogenes. In this study, we performed a comprehensive analysis of long-range chromatin interactions, histone modifications, chromatin accessibility and expression in two gastric cancer (GC) cell lines compared to normal gastric epithelial cells. We found that GC-specific enhancers marked by histone modifications can activate a population of genes, including some oncogenes, by interacting with their proximal promoters. In addition, motif analysis of enhancer-promoter interacting enhancers showed that GC-specific transcription factors are enriched. Among them, we found that MYB is crucial for GC cell growth and activated by the enhancer with an enhancer-promoter loop and TCF7 upregulation. Clinical GC samples showed epigenetic activation of enhancers at the MYB locus and significant upregulation of TCF7 and MYB, regardless of molecular GC subtype and clinicopathological factors. Single-cell RNA sequencing of gastric mucosa with intestinal metaplasia showed high expression of TCF7 and MYB in intestinal stem cells. When we inactivated the loop-forming enhancer at the MYB locus using CRISPR interference (dCas9-KRAB), GC cell growth was significantly inhibited. In conclusion, we identified MYB as an oncogene activated by a loop-forming enhancer and contributing to GC cell growth.

MIAT LncRNA: A multifunctional key player in non-oncological pathological conditions

The discovery of non-coding RNAs (ncRNAs) has unveiled a wide range of transcripts that do not encode proteins but play key roles in several cellular and molecular processes. Long noncoding RNAs (lncRNAs) are specific class of ncRNAs that are longer than 200 nucleotides and have gained significant attention due to their diverse mechanisms of action and potential involvement in various pathological conditions. In the current review, the authors focus on the role of lncRNAs, specifically highlighting the Myocardial Infarction Associated Transcript (MIAT), in non-oncological context. MIAT is a nuclear lncRNA that has been directly linked to myocardial infarction and is reported to control post-transcriptional processes as a competitive endogenous RNA (ceRNA) molecule. It interacts with microRNAs (miRNAs), thereby limiting the translation and expression of their respective target messenger RNA (mRNA) and regulating protein expression. Yet, MIAT has been implicated in other numerous pathological conditions such as other cardiovascular diseases, autoimmune disease, neurodegenerative diseases, metabolic diseases, and many others. In this review, the authors emphasize that MIAT exhibits distinct expression patterns and functions across different pathological conditions and is emerging as potential diagnostic, prognostic, and therapeutic agent. Additionally, the authors highlight the regulatory role of MIAT and shed light on the involvement of lncRNAs and specifically MIAT in various non-oncological pathological conditions.

Cell type specific long non-coding RNA targets identified by integrative analysis of single-cell and bulk colorectal cancer transcriptomes

Long non-coding RNAs (lncRNAs) represent an emerging class of genes which play significant and diverse roles in human cancers. Nevertheless, the functional repertoires of lncRNAs in cancer cell subtypes remains unknown since most studies are focused on protein coding genes. Here, we explored the contribution of lncRNAs in Colorectal Cancer (CRC) heterogeneity. We analyzed 49'436 single-cells from 29 CRC patients and showed that lncRNAs are significantly more cell type specific compared to protein-coding genes. We identified 996 lncRNAs strongly enriched in epithelial cells. Among these, 98 were found to be differentially expressed in tumor samples compared to normal controls, when integrating 270 bulk CRC profiles. We validated the upregulation of two of them (CASC19 and LINC00460) in CRC cell lines and showed their involvement in CRC proliferation by CRISPR-Cas9 knock down experiments. This study highlights a list of novel RNA targets for potential CRC therapeutics, substantiated through experimental validation.

3D epigenomics and 3D epigenopathies

Mammalian genomes are intricately compacted to form sophisticated 3-dimensional structures within the tiny nucleus, so called 3D genome folding. Despite their shapes reminiscent of an entangled yarn, the rapid development of molecular and next-generation sequencing technologies (NGS) has revealed that mammalian genomes are highly organized in a hierarchical order that delicately affects transcription activities. An increasing amount of evidence suggests that 3D genome folding is implicated in diseases, giving us a clue on how to identify novel therapeutic approaches. In this review, we will study what 3D genome folding means in epigenetics, what types of 3D genome structures there are, how they are formed, and how the technologies have developed to explore them. We will also discuss the pathological implications of 3D genome folding. Finally, we will discuss how to leverage 3D genome folding and engineering for future studies. [BMB Reports 2024; 57(5): 216-231].

Noncoding RNAs in skeletal development and disorders

Protein-encoding genes only constitute less than 2% of total human genomic sequences, and 98% of genetic information was previously referred to as "junk DNA". Meanwhile, non-coding RNAs (ncRNAs) consist of approximately 60% of the transcriptional output of human cells. Thousands of ncRNAs have been identified in recent decades, and their essential roles in the regulation of gene expression in diverse cellular pathways associated with fundamental cell processes, including proliferation, differentiation, apoptosis, and metabolism, have been extensively investigated. Furthermore, the gene regulation networks they form modulate gene expression in normal development and under pathological conditions. In this review, we integrate current information about the classification, biogenesis, and function of ncRNAs and how these ncRNAs support skeletal development through their regulation of critical genes and signaling pathways in vivo. We also summarize the updated knowledge of ncRNAs involved in common skeletal diseases and disorders, including but not limited to osteoporosis, osteoarthritis, rheumatoid arthritis, scoliosis, and intervertebral disc degeneration, by highlighting their roles established from in vivo, in vitro, and ex vivo studies.

Functional identification of cis-regulatory long noncoding RNAs at controlled false discovery rates

A key attribute of some long noncoding RNAs (lncRNAs) is their ability to regulate expression of neighbouring genes in cis. However, such 'cis-lncRNAs' are presently defined using ad hoc criteria that, we show, are prone to false-positive predictions. The resulting lack of cis-lncRNA catalogues hinders our understanding of their extent, characteristics and mechanisms. Here, we introduce TransCistor, a framework for defining and identifying cis-lncRNAs based on enrichment of targets amongst proximal genes. TransCistor's simple and conservative statistical models are compatible with functionally defined target gene maps generated by existing and future technologies. Using transcriptome-wide perturbation experiments for 268 human and 134 mouse lncRNAs, we provide the first large-scale survey of cis-lncRNAs. Known cis-lncRNAs are correctly identified, including XIST, LINC00240 and UMLILO, and predictions are consistent across analysis methods, perturbation types and independent experiments. We detect cis-activity in a minority of lncRNAs, primarily involving activators over repressors. Cis-lncRNAs are detected by both RNA interference and antisense oligonucleotide perturbations. Mechanistically, cis-lncRNA transcripts are observed to physically associate with their target genes and are weakly enriched with enhancer elements. In summary, TransCistor establishes a quantitative foundation for cis-lncRNAs, opening a path to elucidating their molecular mechanisms and biological significance.

Super enhancer lncRNAs: a novel hallmark in cancer

Super enhancers (SEs) consist of clusters of enhancers, harboring an unusually high density of transcription factors, mediator coactivators and epigenetic modifications. SEs play a crucial role in the maintenance of cancer cell identity and promoting oncogenic transcription. Super enhancer lncRNAs (SE-lncRNAs) refer to either transcript from SEs locus or interact with SEs, whose transcriptional activity is highly dependent on SEs. Moreover, these SE-lncRNAs can interact with their associated enhancer regions in cis and modulate the expression of oncogenes or key signal pathways in cancers. Inhibition of SEs would be a promising therapy for cancer. In this review, we summarize the research of SE-lncRNAs in different kinds of cancers so far and decode the mechanism of SE-lncRNAs in carcinogenesis to provide novel ideas for the cancer therapy.

An Emerging Role for Enhancer RNAs in Brain Disorders

Noncoding DNA undergoes widespread context-dependent transcription to produce noncoding RNAs. In recent decades, tremendous advances in genomics and transcriptomics have revealed important regulatory roles for noncoding DNA elements and the RNAs that they produce. Enhancers are one such element that are well-established drivers of gene expression changes in response to a variety of factors such as external stimuli, cellular responses, developmental cues, and disease states. They are known to act at long distances, interact with multiple target gene loci simultaneously, synergize with other enhancers, and associate with dynamic chromatin architectures to form a complex regulatory network. Recent advances in enhancer biology have revealed that upon activation, enhancers transcribe long noncoding RNAs, known as enhancer RNAs (eRNAs), that have been shown to play important roles in enhancer-mediated gene regulation and chromatin-modifying activities. In the brain, enhancer dysregulation and eRNA transcription has been reported in numerous disorders from acute injuries to chronic neurodegeneration. Because this is an emerging area, a comprehensive understanding of eRNA function has not yet been achieved in brain disorders; however, the findings to date have illuminated a role for eRNAs in activity-driven gene expression and phenotypic outcomes. In this review, we highlight the breadth of the current literature on eRNA biology in brain health and disease and discuss the challenges as well as focus areas and strategies for future in-depth research on eRNAs in brain health and disease.

Effects of BRD4 inhibitor JQ1 on the expression profile of super-enhancer related lncRNAs and mRNAs in cervical cancer HeLa cells

Objective

To investigate the effects of bromine domain protein 4 (BRD4) inhibitor JQ1 on the expression profile of super-enhancer-related lncRNAs (SE-lncRNAs) and mRNAs in cervical cancer (CC) HeLa-cells.

Methods

The CCK8 method was implemented to detect the inhibitory effect of JQ1 on HeLa cells and explore the best inhibitory concentration. Whole transcriptome sequencing was performed to detect the changes of lncRNAs and mRNAs expression profiles in cells of the JQ1 treatment group and control group, respectively. The differentially expressed SE-lncRNAs were obtained by matching, while the co-expressed mRNAs were obtained by Pearson correlation analysis.

Results

The inhibitory effect of JQ1 on HeLa cell proliferation increased significantly with increasing concentration and treatment time (P < 0.05). Under the experimental conditions of three concentrations of 0.01, 0.1 and 1 μmol/L of JQ1 on HeLa cells at 24, 48, 72 and 120 h, 1 μmol/L of JQ1 at 72 and 120 h had the same cell viability and the strongest cell proliferation inhibition. In order to understand the inhibitory mechanism of JQ1 on HeLa cells, this study analyzed the expression profile differences from the perspective of SE-lncRNAs and mRNAs. A total of 162 SE-lncRNAs were identified, of which 8 SE-lncRNAs were down-regulated and seven SE-lncRNAs were up-regulated. A total of 418 differentially expressed mRNAs related to SE-lncRNAs were identified, of which 395 mRNAs had positive correlation with 12 SE-lncRNAs and 408 mRNAs had negative correlation with 15 SE-lncRNAs.

Conclusion

JQ1 can significantly inhibit the proliferation of HeLa cells and affect the expression profile of SE-lncRNAs and mRNAs.

Long Noncoding RNA RP11-278A23.1, a Potential Modulator of p53 Tumor Suppression, Contributes to Colorectal Cancer Progression

Recently, many studies revealed that long noncoding RNAs (lncRNAs) play important roles in cancers. To identify lncRNAs contributing to colorectal cancers, we screened lncRNAs through expression and survival analyses in datasets from The Cancer Genome Atlas (TCGA). The screen revealed that RP11-278A23.1 expression is significantly increased in colorectal cancer tissues compared with normal tissues and that high RP11-278A23.1 expression correlates with poor prognosis. The knockdown of RP11-278A23.1 inhibited the growth of and promoted apoptosis in colorectal cancer cells. Next, to comprehensively examine differentially expressed genes after RP11-278A23.1 knockdown, RNA sequencing was performed in HCT116 cells. The expression of p21, a p53 target gene, was significantly upregulated, and the expression of several p53 target proapoptotic genes was also altered. RP11-278A23.1 knockdown increased p53 expression at the translational level but not at the transcriptional level. Interestingly, RP11-278A23.1 knockdown also altered the expression of these proapoptotic genes in DLD1 cells with mutated p53 and in p53-knockout HCT116 cells. These results suggest that RP11-278A23.1 modifies the expression of these apoptosis-related genes in p53-dependent and p53-independent manners. In summary, lncRNA RP11-278A23.1 contributes to colorectal cancer progression by promoting cell growth and inhibiting apoptosis, suggesting that this lncRNA may be a useful therapeutic target.

The role of long non-coding RNA in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent liver malignancy with complex etiology and generally poor prognosis. Recently, long non-coding RNAs (lncRNAs), non-protein-coding RNA molecules exceeding 200 nucleotides, have emerged as pivotal players in HCC, influencing its initiation, progression, invasion, and metastasis. These lncRNAs modulate gene expression at epigenetic, transcriptional, and post-transcriptional levels, actively participating in the pathological and physiological processes of HCC. Understanding the intricate relationship between lncRNAs and HCC is important for improving prognosis and reducing mortality. This review summarizes advancements in elucidating the role of lncRNAs in HCC pathogenesis.