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

LINC-PINT plays an anti-tumor role in nasopharyngeal carcinoma by binding to XRCC6 and affecting its function

BACKGROUND

LINC-PINT was downregulated in nasopharyngeal carcinoma (NPC) and correlated with treatment efficiency of NPC. However, the underlying mechanism of LINC-PINT in NPC has not yet been fully explored.

METHOD

We used CellTiter luminescent assay, clone formation assay, Hoechst staining, and SYTO-9/PI staining to examine cell viability and cell apoptosis regulated by LINC-PINT in NPC cells. Xenograft tumor model, HE staining, Ki67 staining, and TUNEL assay were conducted to assess the role of LINC-PINT in vivo. Bioinformatics and RNA immunoprecipitation assay was performed to identify the binding protein of LINC-PINT. Fluorescence in situ hybridization and immunofluorescence were utilized to measure the colocalization of XRCC6 with LINC-PINT and DNA-PKcs. Mito-Tracker red CMXRos staining was used to label mitochondria in cells specifically.

RESULT

We found LINC-PINT was downregulated in many tumors (including NPC) and associated with poor prognosis. The cell viability was significantly inhibited and cell apoptosis was remarkably promoted in LINC-PINT overexpressed cells in contrast to control cells. The growth of tumor xenografts was significantly suppressed and the tumor weight was significantly decreased in LINC-PINT overexpression group compared to the control group. Correspondingly, the positive Ki67 foci was decreased while TUNEL foci was increased in LINC-PINT overexpression group. Mechanically, we verified XRCC6 as a new binding protein of LINC-PINT through RNA binding domains prediction, RIP and colocalization of LINC-PINT and XRCC6. By binding to XRCC6, LINC-PINT interfered the formation of DNA-PK complex, regulated mitochondria accumulation status and affected the modification of apoptosis proteins, leading to more cell apoptosis.

CONCLUSION

Our study provided the first evidence that LINC-PINT promotes cell apoptosis in NPC by binding to XRCC6 and affecting its function.

The Potential Links between lncRNAs and Drug Tolerance in Lung Adenocarcinoma

Lung cancer patients treated with targeted therapies frequently respond well but invariably relapse due to the development of drug resistance. Drug resistance is in part mediated by a subset of cancer cells termed "drug-tolerant persisters" (DTPs), which enter a dormant, slow-cycling state that enables them to survive drug exposure. DTPs also exhibit stem cell-like characteristics, broad epigenetic reprogramming, altered metabolism, and a mutagenic phenotype mediated by adaptive mutability. While several studies have characterised the transcriptional changes that lead to the altered phenotypes exhibited in DTPs, these studies have focused predominantly on protein coding changes. As long non-coding RNAs (lncRNAs) are also implicated in the phenotypes altered in DTPs, it is likely that they play a role in the biology of drug tolerance. In this review, we outline how lncRNAs may contribute to the key characteristics of DTPs, their potential roles in tolerance to targeted therapies, and the emergence of genetic resistance in lung adenocarcinoma.

Non-coding RNAs as skin disease biomarkers, molecular signatures, and therapeutic targets

Non-coding RNAs (ncRNAs) are emerging as biomarkers, molecular signatures, and therapeutic tools and targets for diseases. In this review, we focus specifically on skin diseases to highlight how two classes of ncRNAs-microRNAs and long noncoding RNAs-are being used to diagnose medical conditions of unclear etiology, improve our ability to guide treatment response, and predict disease prognosis. Furthermore, we explore how ncRNAs are being used as both as drug targets and associated therapies have unique benefits, risks, and challenges to development, but offer a distinctive promise for improving patient care and outcomes.

Lnc-PTCHD4-AS inhibits gastric cancer through MSH2-MSH6 dimerization and ATM-p53-p21 activation

Conserved long non-coding RNAs (lncRNAs) have not thoroughly been studied in many cancers, including gastric cancer (GC). We have identified a novel lncRNA PTCHD4-AS which was highly conserved between humans and mice and naturally downregulated in GC cell lines and tissues. Notably, PTCHD4-AS was found to be transcriptionally induced by DNA damage agents and its upregulation led to cell cycle arrest at the G2/M phase, in parallel, it facilitated the cell apoptosis induced by cisplatin (CDDP) in GC. Mechanistically, PTCHD4-AS directly bound to the DNA mismatch repair protein MSH2-MSH6 dimer, and facilitated the binding of dimer to ATM, thereby promoting the expression of phosphorylated ATM, p53 and p21. Here we conclude that the upregulation of PTCHD4-AS inhibits proliferation and increases CDDP sensitivity of GC cells via binding with MSH2-MSH6 dimer, activating the ATM-p53-p21 pathway.

lncRNAs-EZH2 interaction as promising therapeutic target in cutaneous melanoma

Melanoma is the most lethal skin cancer with increasing incidence worldwide. Despite a great improvement of diagnostics and treatment of melanoma patients, this disease is still a serious clinical problem. Therefore, novel druggable targets are in focus of research. EZH2 is a component of the PRC2 protein complex that mediates epigenetic silencing of target genes. Several mutations activating EZH2 have been identified in melanoma, which contributes to aberrant gene silencing during tumor progression. Emerging evidence indicates that long non-coding RNAs (lncRNAs) are molecular "address codes" for EZH2 silencing specificity, and targeting lncRNAs-EZH2 interaction may slow down the progression of many solid cancers, including melanoma. This review summarizes current knowledge regarding the involvement of lncRNAs in EZH2-mediated gene silencing in melanoma. The possibility of blocking lncRNAs-EZH2 interaction in melanoma as a novel therapeutic option and plausible controversies and drawbacks of this approach are also briefly discussed.

Regulation of the Cell Cycle by ncRNAs Affects the Efficiency of CDK4/6 Inhibition

Cyclin-dependent kinases (CDKs) regulate cell division at multiple levels. Aberrant proliferation induced by abnormal cell cycle is a hallmark of cancer. Over the past few decades, several drugs that inhibit CDK activity have been created to stop the development of cancer cells. The third generation of selective CDK4/6 inhibition has proceeded into clinical trials for a range of cancers and is quickly becoming the backbone of contemporary cancer therapy. Non-coding RNAs, or ncRNAs, do not encode proteins. Many studies have demonstrated the involvement of ncRNAs in the regulation of the cell cycle and their abnormal expression in cancer. By interacting with important cell cycle regulators, preclinical studies have demonstrated that ncRNAs may decrease or increase the treatment outcome of CDK4/6 inhibition. As a result, cell cycle-associated ncRNAs may act as predictors of CDK4/6 inhibition efficacy and perhaps present novel candidates for tumor therapy and diagnosis.

Clinical implications of lncRNA LINC-PINT in cancer

Long noncoding RNAs (lncRNAs) possess the potential for therapeutic targeting to treat many disorders, including cancers. Several RNA-based therapeutics (ASOs and small interfering RNAs) have gained FDA approval over the past decade. And with their potent effects, lncRNA-based therapeutics are of emerging significance. One important lncRNA target is LINC-PINT, with its universalized functions and relationship with the famous tumor suppressor gene TP53. Establishing clinical relevance, much like p53, the tumor suppressor activity of LINC-PINT is implicated in cancer progression. Moreover, several molecular targets of LINC-PINT are directly or indirectly used in routine clinical practice. We further associate LINC-PINT with immune responses in colon adenocarcinoma, proposing the potential utility of LINC-PINT as a novel biomarker of immune checkpoint inhibitors. Collectively, current evidence suggests LINC-PINT can be considered for use as a diagnostic/prognostic marker for cancer and several other diseases.

Long Noncoding RNA SAMMSON Promotes Melanoma Progression by Inhibiting FOXA2 Expression

Long noncoding RNAs (lncRNAs) play crucial roles in melanoma initiation and development, serving as potential therapeutic targets and prognostic markers for melanoma. lncRNA survival-associated mitochondrial melanoma-specific oncogenic noncoding RNA (SAMMSON) is upregulated in many types of human cancers. However, the functions of SAMMSON in melanoma have not been fully elucidated. This study is aimed at investigating the expression and functions of SAMMSON in melanoma development. Bioinformatics analysis was performed to determine the expression of SAMMSON and its correlation with the 10-year overall survival (OS) in melanoma patients. Cell proliferation, migration, invasion, and tumorigenesis were detected by MTT, colony formation, Transwell assays, and mouse xenograft model. The expression of cell cycle-related factors, epithelial-to-mesenchymal transition (EMT) makers, and matrix metalloproteinases (MMPs) was assessed by RT-qPCR and western blotting analysis. The results demonstrated that SAMMSON expression was upregulated in melanoma tissues and cells, and lower SAMMSON expression was correlated with longer 10-year OS. SAMMSON knockdown decreased the proliferation, migration, and invasion of melanoma cells by regulating the expression of proliferation-related genes, EMT factors, and MMPs, respectively. Additionally, Forkhead box protein A2 (FOXA2) was confirmed to be a target of SAMMSON, and the biological effects induced by FOXA2 overexpression were similar to those induced by SAMMSON silencing in melanoma cells. Further studies showed that SAMMSON downregulated FOXA2 expression in melanoma cells by modulating the EZH2/H3K27me3 axis. Taken together, our data indicate that SAMMSON plays an important role in melanoma progression and can be a valuable biomarker and therapeutic target in melanoma.

Upregulation LncRNA MEG3 expression suppresses proliferation and metastasis in melanoma via miR-208/SOX4

Long non-coding RNAs (lncRNAs) regulate gene expression and play a significant role in cancer progression. Previously, downregulation of lncRNA MEG3 was shown to associate with poor clinical outcomes in melanoma patients. The basis for this association has not been described and the aims of this study were to identify a role for lncRNA MEG3 in melanoma and to describe its regulatory mechanism of action. RT-qPCR was used to detect lncRNA MEG3 expression in melanoma cells and tissues. Luciferase reporter assays were used to identify lncRNA MEG3 downstream targets. Melanoma cells were transfected with various expression vectors and these transfected cells were assessed for; migration, colony formation, proliferation, in vivo tumorigenesis, and metastatic potential. Melanoma cell lines were found to be sensitive to lncRNA MEG3 expression levels and overexpression was found to inhibit melanoma cell proliferation and invasion, both in vitro and in vivo. Luciferase reporter assays identified miR-208 and SOX4 as downstream targets of lncRNA MEG3. Overexpression of miR-208 and silencing of SOX4 rescued invasion and proliferation by cells that overexpressed lncRNA MEG3. Moreover, lncRNA MEG3 inhibited cancer stem cell differentiation and suppressed melanoma progression and metastasis through inhibition of miR-208 by SOX4.

Novel insights into histone lysine methyltransferases in cancer therapy: From epigenetic regulation to selective drugs

The reversible and precise temporal and spatial regulation of histone lysine methyltransferases (KMTs) is essential for epigenome homeostasis. The dysregulation of KMTs is associated with tumor initiation, metastasis, chemoresistance, invasiveness, and the immune microenvironment. Therapeutically, their promising effects are being evaluated in diversified preclinical and clinical trials, demonstrating encouraging outcomes in multiple malignancies. In this review, we have updated recent understandings of KMTs' functions and the development of their targeted inhibitors. First, we provide an updated overview of the regulatory roles of several KMT activities in oncogenesis, tumor suppression, and immune regulation. In addition, we summarize the current targeting strategies in different cancer types and multiple ongoing clinical trials of combination therapies with KMT inhibitors. In summary, we endeavor to depict the regulation of KMT-mediated epigenetic landscape and provide potential epigenetic targets in the treatment of cancers.

Long non-coding RNAs and melanoma: From diagnosis to therapy

Although extremely rare, malignant melanoma is the deadliest type of skin malignancy with the inherent capability to invade other organs and metastasize to distant tissues. In 2021, it was estimated that approximately 106,110 patients may have received the diagnosis of melanoma, with a mortality rate of 7180. Surgery remains the common choice for treatment in patients with melanoma. Despite many advances in the treatment of melanoma, some patients, such as those who have received cytotoxic chemotherapeutic and immunotherapic agents, a significant number of patients may show inadequate treatment response following initiating these treatments. Non-coding RNAs, including lncRNAs, have become recently popular and attracted the attention of many researchers to make new insights into the pathogenesis of many diseases, particularly malignancies. LncRNAs have been thoroughly investigated in multiple cancers such as melanoma and have been shown to play a major role in regulating various physiological and pathological cellular processes. Considering their core regulatory function, these non-coding RNAs may be appropriate candidates for melanoma patients' diagnosis, prognosis, and treatment. In this review, we will cover all the current literature available for lncRNAs in melanoma and will discuss their potential benefits as diagnostic and/or prognostic markers or potent therapeutic targets in the treatment of melanoma patients.

The role of lncRNAs in the tumor microenvironment and immunotherapy of melanoma

Melanoma is one of the most lethal tumors with highly aggressive and metastatic properties. Although immunotherapy and targeted therapy have certain therapeutic effects in melanoma, a significant proportion of patients still have drug resistance after treatment. Recent studies have shown that long noncoding RNAs (lncRNAs) are widely recognized as regulatory factors in cancer. They can regulate numerous cellular processes, including cell proliferation, metastasis, epithelial-mesenchymal transition (EMT) progression and the immune microenvironment. The role of lncRNAs in malignant tumors has received much attention, whereas the relationship between lncRNAs and melanoma requires further investigation. Our review summarizes tumor suppressive and oncogenic lncRNAs closely related to the occurrence and development of melanoma. We summarize the role of lncRNAs in the immune microenvironment, immunotherapy and targeted therapy to provide new targets and therapeutic methods for clinical treatment.

Comprehensive transcriptomic analysis of immune-related eRNAs associated with prognosis and immune microenvironment in melanoma

Background

Recent evidence suggests that enhancer RNAs (eRNAs) play key roles in cancers. Identification of immune-related eRNAs (ireRNAs) in melanoma can provide novel insights into the mechanisms underlying its genesis and progression, along with potential therapeutic targets.

Aim

To establish an ireRNA-related prognostic signature for melanoma and identify potential drug candidates.

Methods

The ireRNAs associated with the overall survival (OS-ireRNAs) of melanoma patients were screened using data from The Cancer Genome Atlas (TCGA) via WGCNA and univariate Cox analysis. A prognostic signature based on these OS-ireRNAs was then constructed by performing the least absolute shrinkage and selection operator (LASSO) Cox regression analysis. The immune landscape associated with the prognostic model was evaluated by the ESTIMATE algorithm and CIBERSORT method. Finally, the potential drug candidates for melanoma were screened through the cMap database.

Results

A total of 24 OS-ireRNAs were obtained, of which 7 ireRNAs were used to construct a prognostic signature. The ireRNAs-related signature performed well in predicting the overall survival (OS) of melanoma patients. The risk score of the established signature was further verified as an independent risk factor, and was associated with the unique tumor microenvironment in melanoma. We also identified several potential anti-cancer drugs for melanoma, of which corticosterone ranked first.

Conclusions

The ireRNA-related signature is an effective prognostic predictor and provides reliable information to better understand the mechanism of ireRNAs in the progression of melanoma.

Selective EZH2 inhibitor zld1039 alleviates inflammation in cisplatin-induced acute kidney injury partially by enhancing RKIP and suppressing NF-κB p65 pathway

Enhancer of zeste homolog 2 (EZH2), a component of polycomb repressive complex 2 (PRC2), is a histone lysine methyltransferase mediating trimethylation of histone H3 at lysine 27 (H3K27me3), which is a repressive marker at the transcriptional level. EZH2 sustains normal renal function and its overexpression has bad properties. Inhibition of EZH2 overexpression exerts protective effect against acute kidney injury (AKI). A small-molecule compound zld1039 has been developed as an efficient and selective EZH2 inhibitor. In this study, we evaluated the efficacy of zld1039 in the treatment of cisplatin-induced AKI in mice. Before injection of cisplatin (20 mg/kg, i.p.), mice were administered zld1039 (100, 200 mg/kg, i.g.) once, then in the following 3 days. We found that cisplatin-treated mice displayed serious AKI symptoms, evidenced by kidney dysfunction and kidney histological injury, accompanied by EZH2 upregulation in the nucleus of renal tubular epithelial cells. Administration of zld1039 dose-dependently alleviated renal dysfunction as well as the histological injury, inflammation and cell apoptosis in cisplatin-treated mice. We revealed that zld1039 administration exerted an anti-inflammatory effect in kidney of cisplatin-treated mice via H3K27me3 inhibition, raf kinase inhibitor protein (RKIP) upregulation and NF-κB p65 repression. In the cisplatin-treated mouse renal tubular epithelial (TCMK-1) cells, silencing of RKIP with siRNA did not abolish the anti-inflammatory effect of EZH2 inhibition, suggesting that RKIP was partially involved in the anti-inflammatory effect of zld1039. Collectively, EZH2 inhibition alleviates inflammation in cisplatin-induced mouse AKI via upregulating RKIP and blocking NF-κB p65 signaling in cisplatin-induced AKI. The potent and selective EZH2 inhibitor zld1039 has the potential as a promising agent for the treatment of AKI.

PINTology: A short history of the lncRNA LINC-PINT in different diseases

LINC-PINT is a p53-induced long intergenic noncoding transcript that plays a crucial role in many diseases, especially cancer. This long noncoding RNA (lncRNA) gene produces in total 102 (LNCipedia) alternatively spliced variants (LINC-PINT:1 to LINC-PINT:102). The functions of known variants include RNA transcripts, host transcripts for circular RNA (circRNA) generation and as sources for the translation of short peptides. In most human tumors, LINC-PINT is down-regulated where it serves as a tumor suppressor. However, the diversity of its functions in other maladies signifies its general clinical importance. Current LINC-PINT molecular functions include RNA-protein interactions, miRNA sponging and epigenetic modulation with these mechanisms operating in different cellular contexts to exert effects on biological processes ranging from DNA damage responses, cell cycle and growth arrest, senescence, cell migration and invasion, and apoptosis. Genetic polymorphisms in LINC-PINT have also been functionally associated with cancer and other pathologies including the autoimmune diseases pemphigus foliaceus and arthritis. Hence, LINC-PINT shows great potential as a clinical biomarker, especially for the diagnosis and prognosis of cancer. In this review, we explore the current knowledge highlighting the distinctive molecular functions of LINC-PINT in specific cancers and other disease states. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Emerging role of lncRNA ELDR in development and cancer

Whole-genome sequencing and transcriptome analysis revealed more than 90% of the human genome transcribes noncoding RNAs including lncRNAs. From the beginning of the 21st century, lncRNAs have gained widespread attention as a new layer of regulation in biological processes. lncRNAs are > 200 nucleotides in size, transcribed by RNA polymerase II, and share many similarities with mRNAs. lncRNA interacts with DNA, RNA, protein, and miRNAs, thereby regulating many biological processes. In this review, we have focused mainly on LINC01156 [also known as the EGFR long non-coding downstream RNA (ELDR) or Fabl] and its biological importance. ELDR is a newly identified lncRNA and first reported in a mouse model, but it has a human homolog. The human ELDR gene is closely localized downstream of epidermal growth factor receptor (EGFR) gene at chromosome 7 on the opposite strand. ELDR is highly expressed in neuronal stem cells and associated with neuronal differentiation and mouse brain development. ELDR is upregulated in head and neck cancer, suggesting its role as an oncogene and its importance in prognosis and therapy. Publicly available RNA-seq data further support its oncogenic potential in different cancers. Here, we summarize all the aspects of ELDR in development and cancer, highlighting its future perspectives in the context of mechanism.

New Insights into the Roles of lncRNAs as Modulators of Cytoskeleton Architecture and Their Implications in Cellular Homeostasis and in Tumorigenesis

The importance of the cytoskeleton not only in cell architecture but also as a pivotal element in the transduction of signals that mediate multiple biological processes has recently been highlighted. Broadly, the cytoskeleton consists of three types of structural proteins: (1) actin filaments, involved in establishing and maintaining cell shape and movement; (2) microtubules, necessary to support the different organelles and distribution of chromosomes during cell cycle; and (3) intermediate filaments, which have a mainly structural function showing specificity for the cell type where they are expressed. Interaction between these protein structures is essential for the cytoskeletal mesh to be functional. Furthermore, the cytoskeleton is subject to intense spatio-temporal regulation mediated by the assembly and disassembly of its components. Loss of cytoskeleton homeostasis and integrity of cell focal adhesion are hallmarks of several cancer types. Recently, many reports have pointed out that lncRNAs could be critical mediators in cellular homeostasis controlling dynamic structure and stability of the network formed by cytoskeletal structures, specifically in different types of carcinomas. In this review, we summarize current information available about the roles of lncRNAs as modulators of actin dependent cytoskeleton and their impact on cancer pathogenesis. Finally, we explore other examples of cytoskeletal lncRNAs currently unrelated to tumorigenesis, to illustrate knowledge about them.

The pleiotropic roles of circular and long noncoding RNAs in cutaneous melanoma

Cutaneous melanoma (CM) is a very aggressive disease, often characterized by unresponsiveness to conventional therapies and high mortality rates worldwide. The identification of the activating BRAFV600 mutations in approximately 50% of CM patients has recently fueled the development of novel small-molecule inhibitors that specifically target BRAFV600 -mutant CM. In addition, a major progress in CM treatment has been made by monoclonal antibodies that regulate the immune checkpoint inhibitors. However, although target-based therapies and immunotherapeutic strategies have yielded promising results, CM treatment remains a major challenge. In the last decade, accumulating evidence points to the aberrant expression of different types of noncoding RNAs (ncRNAs) in CM. While studies on microRNAs have grown exponentially leading to significant insights on CM biology, the role of circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs) in this tumor is less understood, and much remains to be discovered. Here, we summarize and critically review the available evidence on the molecular functions of circRNAs and lncRNAs in BRAFV600 -mutant CM and CM immunogenicity, providing recent updates on their functional role in targeted therapy and immunotherapy resistance. In addition, we also include an evaluation of several algorithms and databases for prediction and validation of circRNA and lncRNA functional interactions.

Role of Long Non-coding RNAs in the Pathogenesis of Alzheimer's and Parkinson's Diseases

Neurodegenerative diseases are a diverse group of diseases that are now one of the leading causes of morbidity in the elderly population. These diseases include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Amyotrophic Lateral Sclerosis (ALS), etc. Although these diseases have a common characteristic feature of progressive neuronal loss from various parts of the brain, they differ in the clinical symptoms and risk factors, leading to the development and progression of the diseases. AD is a neurological condition that leads to dementia and cognitive decline due to neuronal cell death in the brain, whereas PD is a movement disorder affecting neuro-motor function and develops due to the death of the dopaminergic neurons in the brain, resulting in decreased dopamine levels. Currently, the only treatment available for these neurodegenerative diseases involves reducing the rate of progression of neuronal loss. This necessitates the development of efficient early biomarkers and effective therapies for these diseases. Long non-coding RNAs (LncRNAs) belong to a large family of non-coding transcripts with a minimum length of 200 nucleotides. They are implied to be involved in the development of the brain, a variety of diseases, and epigenetic, transcriptional, and posttranscriptional levels of gene regulation. Aberrant expression of lncRNAs in the CNS is considered to play a major role in the development and progression of AD and PD, two of the most leading causes of morbidity among elderly populations. In this mini-review, we discuss the role of various long non-coding RNAs in neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, which can further be studied for the development of potential biomarkers and therapeutic targets for various neurodegenerative diseases.

LncRNA TUG1 promotes bladder cancer malignant behaviors by regulating the miR-320a/FOXQ1 axis

BACKGROUND

Growing evidence has showed long noncoding RNAs (lncRNAs) play critical roles in bladder cancer (BC) progression. LncRNA taurine upregulated gene 1 (TUG1) was involved in the development of human malignancies. However, the intrinsic and concrete molecular mechanisms of TUG1 in BC remain largely unknown.

METHODS

Expression patterns of TUG1, miR-320a and FOXQ1 in BC tissues and cell lines were measured using qRT-PCR and western blot, respectively. Cell proliferation was detected by CCK-8 and colony formation assays. The capacity of cell migration and invasion was evaluated using wound healing and transwell assay. Tumor xenograft assay was performed to further validate the role of TUG1 in BC progression. Dual luciferase reporter assay and FISH analysis were employed to verify the TUG1/miR-320a/FOXQ1 regulatory network.

RESULTS

TUG1 was significantly higher expression in BC specimens and cell lines. TUG1 knockdown suppressed BC cells malignant behaviors in vitro and inhibited tumor growth and metastasis in vivo, while TUG1 overexpression promoted BC cells malignant behaviors in vitro. However, the function of miR-320a was opposite to that of TUG1, and miR-320a inhibitor partially eliminated the inhibitory effect of TUG1 knockdown on the malignant behavior of BC cells. As a microRNA sponge, TUG1 actively elevated FOXQ1 expression to sponge miR-320a and subsequently promoted BC cells malignant phenotypes.

CONCLUSION

TUG1 may have great potential as therapeutic target for BC, since TUG1 silencing inhibited cell proliferation, migration and invasion in BC, while promoted cell apoptosis, by regulating the miR-320a/FOXQ1 axis.

MicroRNA-367-3p suppresses sevoflurane-induced adult rat astrocyte apoptosis by targeting BCL2L11

The present study aimed to characterize the effect of microRNA (miR)-367-3p on sevoflurane anesthesia and elucidate the underlying mechanism. A total of 36 4-month-old adult Sprague-Dawley rats were divided into six groups. Sevoflurane was inhaled at concentrations of 0, 1, 2, 4, 8 and 16% for a total of 6 h; the hippocampus of the brain was subsequently minced and digested, and astrocytes were isolated. Various methods, including reverse transcription-quantitative (RT-q)PCR, western blotting and TUNEL staining, were used to determine the expression levels of Bax, BCL-2 and BCL-2-like protein 11 (BCL2L11), as well as the level of apoptosis. The rats were treated with 8% sevoflurane and the astrocytes from the rats were transfected with miR-367-3p or anti-miR-367-3p. The present study demonstrated that sevoflurane promoted astrocytes apoptosis. Western blotting revealed that with an increase of sevoflurane concentration, the expression levels of the apoptotic proteins Bax and BCL2L11 were significantly increased, whereas the protein expression levels of BCL-2 were significantly decreased. However, overexpression of miR-367-3p reversed these effects. TUNEL staining revealed that sevoflurane promoted the apoptosis of astrocytes, while apoptosis was reversed by miR-367-3p overexpression. RT-qPCR demonstrated that sevoflurane inhibited the expression of miR-367-3p. Notably, miR-367-3p reduced the expression of BCL2L11, thereby inhibiting the apoptosis of astrocytes originating from the hippocampal area of adult rats induced by sevoflurane. Therefore, miR-367-3p and BCL2L11 may act as effective targets for the study of anesthesia.

Upregulation of leukemia-induced non-coding activator RNA (LUNAR1) predicts poor outcome in pediatric T-acute lymphoblastic leukemia

T-cell Acute Lymphoblastic Leukemia (T-ALL) accounts for around 10-15% of all lymphoblastic leukemia in children. Previous studies have proven that dysregulation of Leukemia-induced non-coding activator RNA-1 (LUNAR1) expression promotes T-ALL cell growth by enhancing the NOTCH1/IGF-1R signaling pathway. We aimed to investigate the prognostic value of LUNAR1 in pediatric T-ALL, in addition, to find out its association with NOTCH1 and IGF-1R. The LUNAR1, NOTCH1, and IGF-IR gene expression were measured in peripheral blood (PB) samples of l85 children with T-ALL and forty non-leukemic samples as a control group. Cox regression analysis revealed that overexpression of LUNAR1, NOTCH1, and IGF-IR was significantly correlated with poor prognosis, short overall survival, and progression-free survival. We concluded that LUNAR1 could serve as an independent prognostic biomarker for T-ALL in children.

Emerging Roles of LncRNAs in the EZH2-regulated Oncogenic Network

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

Long intragenic non-coding RNA p53-induced transcript (LINC-PINT) as a novel prognosis indicator and therapeutic target in cancer

Cancer involves complex etiology factors, multiple stages, and intricate gene mutations. Long non-coding RNAs (lncRNAs) are implicated as molecular mechanisms underlying human genomic activity in various physiologic and pathophysiologic conditions. However, the sophisticated modifications and regulatory processes linking lncRNAs to cancer initiation and progression have not yet been fully explored. Long intragenic non-coding RNA p53-induced transcript (LINC-PINT) is an lncRNA that functions as a tumor suppressor gene involved in various tumors and malignant activities. LINC-PINT is downregulated in nasopharyngeal cancer, renal carcinoma, non-small cell lung cancer, glioblastoma, thyroid cancer, retinoblastoma, ovarian cancer, breast cancer, esophageal squamous cell carcinoma, osteosarcoma, melanoma, and gastric cancer. Furthermore, decreased LINC-PINT expression predicts poor prognosis and advanced clinical tumor stages. Together, these studies indicate that LINC-PINT could serve as a diagnostic and prognostic indicator in cancer. The specific lncRNA regulatory mechanism of LINC-PINT may also be a novel target for cancer therapies.

Pathogenic roles of long noncoding RNAs in melanoma: Implications in diagnosis and therapies

Melanoma is one of the most dangerous types of cutaneous neoplasms, which are pigment-producing cells of neuroectodermal origin found all over the body. A great deal of research is focused on the mechanisms of melanoma to promote better diagnostic and treatment options for melanoma in its advanced stages. The progression of melanoma involves alteration in different levels of gene expression. With the successful implementation of next-generation sequencing technology, an increasing number of long noncoding RNAs (lncRNAs) sequences have been discovered, and a significant number of them have phenotypic effects in both in vitro and in vivo studies, implying that they play an important role in the occurrence and progression of human cancers, particularly melanoma. A number of evidence indicated that lncRNAs are important regulators in tumor cell proliferation, invasion, apoptosis, immune escape, energy metabolism, drug resistance, epigenetic regulation. To better understand the role of lncRNAs in melanoma tumorigenesis, we categorize melanoma-associated lncRNAs according to their cellular functions and associations with gene expression and signaling pathways in this review. Based on the mechanisms of lncRNA, we discuss the possibility of lncRNA-target treatments, and the application of liquid biopsies to detect lncRNAs in melanoma diagnosis and prognosis.

LncRNA CCDC144NL-AS1 Serves as a Prognosis Biomarker for Non-small Cell Lung Cancer and Promotes Cellular Function by Targeting miR-490-3p

This study revealed the prognostic significance of long non-coding RNA (lncRNA) CCDC144NL-AS1 in NSCLC patients and discussed the effect and mechanism of proliferation, migration, and invasion of non-small cell lung cancer (NSCLC) cells. 128 pairs of NSCLC tissues and paracancerous tissues were collected, and qRT-PCR was used to detect the differential expression of lncRNA CCDC144NL-AS1 in all tissues and cells lines. Kaplan-Meier analysis and Cox proportional hazards model analysis were used to estimate the prognostic value of lncRNA CCDC144NL-AS1. CCK-8 and Transwell assays confirmed the effect of lncRNA CCDC144NL-AS1 on the proliferation, migration, and invasion of NSCLC. Bioinformatics was used to predict the microRNAs that lncRNA CCDC144NL-AS1 might bind to miR-490-3p. The regulation of lncRNA CCDC144NL-AS1 on miR-490-3p was verified by luciferase activity assay with wide type or mutation. The expression of lncRNA CCDC144NL-AS1 was enhanced in both NSCLC tissues and cell lines. Patients with overexpression of lncRNA CCDC144NL-AS1 have a poor prognosis, and lncRNA CCDC144NL-AS1 is an independent prognostic factor for NSCLC. Increased the relative expression level of lncRNA CCDC144NL-AS1 can promote the proliferation, migration, and invasion of NSCLC cells. LncRNA CCDC144NL-AS1 might target miR-490-3p. LncRNA CCDC144NL-AS1 can be used as an oncogene of NSCLC to predict patient prognosis and promote tumor proliferation, migration, and invasion by targeting miR-490-3p.

LINC-PINT Inhibited Malignant Progression of Bladder Cancer by Targeting miR-155-5p

BACKGROUND

This study mainly explored the expression level of LINC-PINT in bladder cancer and its relationship with prognosis. Meanwhile, the effect of LINC-PINT on the biological function of bladder cancer was also explored.

METHODS

The expression levels of LINC-PINT and miR-155-5p were detected by qRT-PCR. The prognostic significance of LINC-PINT in bladder cancer was studied by the Kaplan-Meier curve and Log rank test. CCK-8 and Transwell assays were used to analyze the proliferation, migration, and invasion ability. The targeting relationship between LINC-PINT and miR-155-5p was analyzed using bioinformatics and dual-luciferase reporter assays.

RESULTS

The expression of LINC-PINT was downregulated in bladder cancer tissues and cell lines, and miR-155-5p showed the opposite trend in bladder cancer tissues. Kaplan-Meier curve proved that the patients with low LINC-PINT expression had a lower five-year survival rate and the Log rank test displayed that LINC-PINT was a prognostic factor of BC. CCK-8 and Transwell results showed that LINC-PINT could inhibit the ability of proliferation, migration, and invasion. LINC-PINT was proved to target miR-155-5p in bladder cancer. Dual-luciferase reporter gene assay showed that the relative luciferase activity of overexpression miR-155-5p co-transfected with LINC-PINT-wt was significantly lower. LINC-PINT was negatively correlated with miR-155-5p.

CONCLUSION

LINC-PINT is a potential prognostic marker of bladder cancer, and the up-regulation of Lin-PINT can inhibit the proliferation, invasion, and migration of bladder cancer cells by targeting miR-155-5p.

LncRNA HOTAIR regulates the expression of E-cadherin to affect nasopharyngeal carcinoma progression by recruiting histone methylase EZH2 to mediate H3K27 trimethylation

BACKGROUND/AIM

There has been increasing evidence for the function of long non-coding RNA (lncRNA) in nasopharyngeal carcinoma (NPC). We aim to delve into the position of lncRNA HOX antisense intergenic RNA (HOTAIR), together with enhancer of zeste homolog 2 (EZH2), E-cadherin and trimethylation of lysine 27 on histone H3 (H3K27me3) in NPC.

METHODS

HOTAIR, EZH2, and E-cadherin expression in NPC tissues and cells were tested. NPC cell biological functions were examined through gain-of and loss-of function assays. The mechanism of lncRNA HOTAIR/E-cadherin/EZH2/H3K27 axis in NPC was decoded.

RESULTS

LncRNA HOTAIR and EZH2 were highly expressed in NPC, and E-cadherin was lowly expressed. Down-regulation of HOTAIR or EZH2 inhibited NPC cell progression and tumor growth. HOTAIR recruited histone methylase EZH2 to mediate trimethylation of H3K27 and regulated E-cadherin expression.

CONCLUSION

HOTAIR inhibits E-cadherin by stimulating the trimethylation of H3K27 to promote NPC cell progression through recruiting histone methylase EZH2.

LINC00518 Promotes Cell Proliferation by Regulating the Cell Cycle of Lung Adenocarcinoma Through miR-185-3p Targeting MECP2

Previous studies have shown that long intergenic non-protein coding RNA 00518 (LINC00518) are essential for the cell growth and metastasis of human cancer. However, the role of LINC00518 in lung adenocarcinoma (LUAD) is still unknown. This research put emphasis on the function of LINC00518 on the cell growth of LUAD. The lncRNA, miRNA and mRNA expression were measured by using qRT-PCR. Protein levels were measured by using Western blotting. CCK-8, colony formation assays and transwell assay were performed to evaluate the cell proliferation ability and invasion. Bioinformatic analysis and luciferase reporter assays were chosen to confirm the mechanism of LINC00518 in LUAD. We found that LINC00518 was highly expressed in LUAD specimens and the high-expression was negatively correlated with the overall survival rates. This finding was also proved in the LUAD cell lines. Through a series of in vitro and in vivo experiments, we proved that LICN00518 promoted the cell growth of LUAD by regulating the cell cycle. Moreover, LICN00518 upregulated the expression of MECP2 by mutagenesis of miR-185-3p. The results suggested that LICN00518 could be used as a survival indicator and potential therapeutic target for LUAD patients.

LncRNA LINC-PINT Inhibits Malignant Behaviors of Laryngeal Squamous Cell Carcinoma Cells via Inhibiting ZEB1

Objective: Laryngeal squamous cell carcinoma (LSCC) belongs to head and neck squamous cell carcinoma (HNSCC), with dismal prognosis. Here, this study aims to disclose the role of LINC-PINT in cancer development, which may contribute to improving the clinical outcomes of LSCC treatment.

Methods: LINC-PINT expression in LSCC tissues and in TU-177 and Hep-2 cells was quantified, and subsequently, the association between LINC-PINT and LSCC malignancies was analyzed. pcDNA3.1-LINC-PINT or pcDNA3.1-EZH2 was introduced into Hep-2 and TU-177 cells. qRT-PCR and Western blot analyses examined the levels of proteins related to the AKT/mTOR pathway and their phosphorylated proteins in Hep-2 and TU-177 cells. The viability as well as migration and invasion abilities of Hep-2 and TU-177 cells were determined. Also, the distribution of LINC-PINT in Hep-2 cells was investigated as well as the interplay between LINC-PINT and EZH2. The downstream genes that might interact with EZH2 were screened.

Results: LINC-PINT expression was inhibited in LSCC tissues and in Hep-2 and TU-177 cells, whose downregulation was associated with unsatisfactory prognosis. LINC-PINT overexpression suppressed the proliferative, migratory and invasive capacities of Hep-2 and TU-177 cells. LINC-PINT, mainly expressing in nuclei, could enrich EZH2 to silence ZEB1. In Hep-2 and TU-177 cells, the inhibition of LINC-PINT or overexpression of ZEB1 could enhance cell proliferation, migration and invasion. The phosphorylated levels of proteins related to the AKT/mTOR pathway were declined in cells with LINC-PINT overexpression, and the levels of these phosphorylated proteins were increased in cells with LINC-PINT inhibition.

Conclusion: LINC-PINT enriches EZH2 to silence ZEB1 and thus inhibits the proliferative, migratory, and invasive capacities of Hep-2 and TU-177 cells. In addition, LINC-PINT might exert its biological function through the AKT/mTOR pathway.

Long noncoding RNA LINC01291 promotes the aggressive properties of melanoma by functioning as a competing endogenous RNA for microRNA-625-5p and subsequently increasing IGF-1R expression

Studies have confirmed the relationship between dysregulated long noncoding RNAs and melanoma pathogenesis. However, the regulatory functions of long intergenic non-protein coding RNA 1291 (LINC01291) in melanoma remain unknown. Therefore, we evaluated LINC01291 expression in melanoma and explored its roles in regulating tumor behaviors. Further, the molecular events via which LINC01291 affects melanoma cells were investigated. LINC01291 expression in melanoma cells was analyzed using The Cancer Genome Atlas database and quantitative real-time polymerase chain reaction. Functional assays, including the Cell Counting Kit-8 assay, colony formation assay, flow cytometry, cell migration and invasion assays, and tumor xenograft models, were used to examine LINC01291’s role in melanoma cells. Additionally, bioinformatics analysis, RNA immunoprecipitation, luciferase reporter assay, and western blotting were conducted to determine the tumor-promoting mechanism of LINC01291. LINC01291 was upregulated in melanoma tissues and cell lines. Following LINC01291 knockdown, cell proliferation, colony formation, migration, and invasion were diminished, whereas apoptosis was enhanced and the cell cycle was arrested at G0/G1. In addition, loss of LINC01291 decreased the chemoresistance of melanoma cells to cisplatin. Furthermore, LINC01291 interference inhibited melanoma tumor growth in vivo. Mechanistically, LINC01291 functions as a competing endogenous RNA by sponging microRNA-625-5p (miR-625-5p) in melanoma cells and maintaining insulin-like growth factor 1 receptor (IGF-1R) expression. Rescue experiments revealed that the roles induced by LINC01291 depletion in melanoma cells could be reversed by suppressing miR-625-5p or overexpressing IGF-1R. Our study identified the LINC01291/miR-625-5p/IGF-1R competing endogenous RNA pathway in melanoma cells, which may represent a novel diagnostic biomarker and an effective therapeutic target for melanoma.

Long Noncoding RNA LINC-PINT Suppresses Cell Proliferation, Invasion, and EMT by Blocking Wnt/β-Catenin Signaling in Glioblastoma

Background: Glioblastoma (GBM) represents the most aggressive glioma with high invasive potential. Recent studies proved the involvement of epithelial-mesenchymal transition (EMT) process in increasing the malignancy and invasiveness of GBM. LncRNAs have been verified to play pivotal roles in human disease including GBM. However, the molecular mechanisms of lncRNA-mediated EMT in GBM remain largely unknown. LINC-PINT, a LncRNA which has never been studied in GBM before, was predicted to be negatively associated with EMT in GBM. This study aimed to explore the biological function and the EMT relevance of LINC-PINT in GBM and further explore the molecular mechanism.

Methods: The bioinformatic prediction data of LINC-PINT in GBM was derived from The Cancer Genome Atlas (TCGA) database by R software and GEPIA website. qRT-PCR assay was performed to detect the expression level of LINC-PINT in GBM cell lines. Cell counting kit-8 (CCK8), clone formation, transwell, and wound healing assays were performed to determine the biological function of LINC-PINT in vivo. Tumor xenograft experiment and tumor peritoneal metastasis experiments were performed to verify the in vivo function. Western blot and immunofluorescence staining assays were carried out to detect the relevance of LINC-PINT with EMT and Wnt/β-catenin signaling. Rescue assays were performed to check the regulation mechanism of LINC-PINT/Wnt signaling/EMT axis in GBM.

Results: LINC-PINT was downregulated in GBM cell lines. LINC-PINT suppressed cell progression, invasion, and EMT in GBM. LINC-PINT blocked Wnt/β-catenin signaling in GBM.

Conclusion: LINC-PINT suppressed cell proliferation, invasion, and EMT by blocking Wnt/β-catenin signaling in GBM.

LncRNA PVT1 accelerates malignant phenotypes of bladder cancer cells by modulating miR-194-5p/BCLAF1 axis as a ceRNA

Background: Numerous studies proved that long non-coding RNA (lncRNA) is involved in the progression of multifarious diseases, especially in some carcinomas. As a potential tumor biomarker, plasmacytoma variant translocation 1 gene (PVT1) is involved in the development and progression of multifarious cancers. Nevertheless, the intrinsic and concrete molecular mechanism of PVT1 in bladder cancer still remained unclear, which is also the dilemma faced in many non-coding RNA studies.

Results: Our research revealed that PVT1 was significantly higher expression in bladder carcinoma specimens and cell lines. Further experiments indicated that knockdown or overexpression of PVT1 restrained or promoted the malignant phenotype and WNT/β-catenin signaling in bladder cancer cells. Meanwhile miR-194-5p was in contrast and miR-194-5p could partially reverse the function of PVT1 in malignant bladder tumor cells. As a microRNA sponge, PVT1 actively promotes the expression of b-cells lymphoma-2-associated transcription factor 1 (BCLAF1) to sponge miR-194-5p and subsequently increases malignant phenotypes of bladder cancer cells. Therefore, it performs a carcinogenic effect and miR-194-5p as the opposite function, and serves as an antioncogene in the bladder carcinomas pathogenesis.

Conclusion: PVT1-miR-194-5p-BCLAF1 axis is involved in the malignant progression and development of bladder carcinomas. Experiments revealed that PVT1 has a significant regulatory effect on bladder cancer (BC) and can be used as a clinical diagnostic marker and a therapeutic molecular marker for patients suffering from BC.

Methods: In urothelial bladder carcinoma specimens and cell lines, the relative expression levels of PVT1 and miR-194-5p were detected by quantitative reverse transcription PCR (RT-qPCR). Through experiments such as loss-function and over-expression, the biological effects of PVT1 and miR-194-5p on the proliferation, migration, apoptosis and tumorigenicity were explored in bladder cancer cells. Co-immunoprecipitation, proteomics experiments, dual luciferase reporter gene analysis, western blot and other methods were adopted to investigate the PVT1 potential mechanism in bladder carcinomas.

Inhibition of miR-490-5p Promotes Human Adipose-Derived Stem Cells Chondrogenesis and Protects Chondrocytes via the PITPNM1/PI3K/AKT Axis

MicroRNAs (miRNAs) play a pivotal role in cartilage development and homeostasis in osteoarthritis (OA). While the fundamental roles of miRNAs in cartilage degeneration have been extensively studied, their effects on chondrogenic differentiation induced by human adipose-derived stem cells (hADSCs) and the underlying mechanisms remain largely elusive. Here, we investigated the roles and mechanisms of miRNAs in hADSC chondrogenic differentiation and chondrocyte homeostasis. Using microarray analysis, we screened miRNAs expressed in the chondrogenic differentiated hADSCs and identified miR-490-5p as the most significantly down-regulated miRNA. We analyzed its expression patterns during chondrogenesis in vivo and in vitro. Our study showed that miR-490-5p overexpression promoted the transition of hADSCs from chondrogenesis to osteogenesis. In addition, based on miRNA-mRNA prediction analysis and dual-luciferase reporter assay, we proposed and proved that miR-490-5p targeted PITPNM1 by binding to its 3'-UTR and inhibiting its translation. Moreover, loss- and gain-of-function experiments identified the involvement of the PI3K/AKT signaling pathway, and a rescue experiment determined the effect and specific mechanism of the miR-490-5p/PITPNM1/PI3K/AKT axis in hADSC chondrogenic differentiation and chondrocyte homeostasis. Inhibition of miR-490-5p alleviated cartilage injury in vivo as demonstrated using the destabilization of the medial meniscus (DMM) OA model. We identified miR-490-5p as a novel modulator of hADSC-mediated chondrogenesis and chondrocyte phenotype. This study highlighted that miR-490-5p attenuated hADSC chondrogenesis and accelerated cartilage degradation through activation of the PI3K/AKT signaling pathway by targeting PITPNM1. Inhibition of miR-490-5p facilitated hADSC chondrogenic differentiation and protected chondrocyte phenotype via the PITPNM1/PI3K/AKT axis, thus providing a novel stem cell potential therapeutic target for OA treatment.

lncRNA deleted in lymphocytic leukaemia 1 (DLEU1) promotes the migration and invasion of human embryonic trophoblast cells

To investigate the roles of lncRNA deleted in lymphocytic leukaemia 1 (DLEU1) on migration and invasion of human trophoblast cells. Human chorionic trophoblast cell line HTR8/SVneo was cultured and transfected using lncRNA DLEU1 small interfering RNA. Real-time quantitative polymerase chain reaction was used to detect lncRNA DLEU1 expression. The activity of migration regulatory protein CDC42 was detected by western blot. The downstream miRNA targets of lncRNA and mRNAs targeted by corresponding miRNAs were respectively predicted using bioinformatics analyses. Compared with the control group, the expression of lncRNA DLEU1 in the small interfering RNA group was significantly decreased (P < 0.05). There was no significant change in cell proliferation capacity for transfected cells (lncRNA DLEU1 siRNA-1, P = 0.537; lncRNA DLEU1 siRNA-2, P = 0.384), but cell migration (lncRNA DLEU1 siRNA-1, P = 0.025; lncRNA DLEU1 siRNA-2, P = 0.019) and invasion (lncRNA DLEU1 siRNA-1, P = 0.0327; lncRNA DLEU1 siRNA-2, P = 0.021) was significantly reduced. CDC42 activity in the lncRNA DLEU1 knockdown group decreased and the phosphorylation of cofilin increased. Therefore, downregulation of lncRNA DLEU1 suppressed the migration and invasion of human trophoblast cells.

Emerging roles of long non-coding RNAs in the p53 network

Transcription factor p53 is activated in response to numerous stress stimuli in order to promote repair and survival or death of abnormal cells. For decades, regulatory mechanisms and downstream targets that execute the many biological functions of tumour suppressor p53 largely focused on the products of protein-coding genes. Recently, an entirely new class of molecules, termed long non-coding RNAs (lncRNAs), were discovered as key regulatory players in shaping p53 activity and biological outcomes. Many p53-regulated lncRNAs are now reported to either directly or indirectly intervene in p53-regulatory networks, generally in fine-tuning p53's tumour surveillance programme. Recent studies reveal that signals that converge upon p53 to regulate its activity, and molecules that implement downstream p53-response include both proteins and lncRNAs. In this review, we discuss the non-proteomic component of p53-regulatory networks, focusing on lncRNAs regulated by p53 and/or that regulate p53 activity, and their impact on biological outcomes.

The novel long non-coding RNA LATS2-AS1-001 inhibits gastric cancer progression by regulating the LATS2/YAP1 signaling pathway via binding to EZH2

Background

To explore the expression pattern and role of the novel long non-coding RNA LATS2 antisense transcript 1 (LATS2-AS1-001) in gastric cancer (GC).

Methods

qRT-PCR was applied to evaluate LATS2-AS1-001 expression and correlation with LATS2 in GC. In vitro experiments were performed to investigate the role of LATS2-AS1-001 in GC cells. RNA immunoprecipitation (RIP) was performed to assess the interaction between EZH2 and LATS2-AS1-001. LATS2/YAP1 signaling pathway proteins were detected by immunoblot. Oncomine and KMPLOT data analysis was conducted to assess the prognostic value of YAP1 in GC.

Results

Decreased expression levels of LATS2-AS1-001 and LATS2 were confirmed in 357 GC tissues compared with the normal mucosa. A strong positive correlation between LATS2-AS1-001 and LATS mRNA expression was found in Pearson Correlation analysis (r = 0.719, P < 0.001). Furthermore, ROC curve analysis revealed areas under the curves for LATS2-AS1-001 and LATS2 of 0.7274 and 0.6865, respectively (P < 0.001), which indicated that LATS2-AS1-001 and LATS could be used as diagnostic indicators in GC. Moreover, ectopic expression of LATS2-AS1-001 decreased cell viability, induced G0/G1 phase arrest, and inhibited cell migration and invasion in GC cells. Mechanistically, overexpressing LATS2-AS1-001 upregulated LATS2 and induced YAP1 phosphorylation via binding to EZH2. Oncomine and KMPLOT database analysis demonstrated YAP1 was highly expressed in human GC samples, and high YAP1 expression predicted poor patient prognosis in GC.

Conclusion

This study revealed that lncRNA LATS2-AS1-001 might serve as a potential diagnostic index in GC and act as a suppressor of GC progression.

Brahma Related Gene 1 (Brg1) Regulates Cellular Cholesterol Synthesis by Acting as a Co-factor for SREBP2

Hepatocyte is a hub for cholesterol metabolism. Augmented synthesis of cholesterol in the liver is associated with hypercholesterolemia and contributes to the pathogenesis of a host of cardiovascular and metabolic diseases. Sterol response element binding protein 2 (SREBP2) regulates hepatic cholesterol metabolism by activating the transcription of rate-limiting enzymes in the cholesterol biosynthesis pathway. The underlying epigenetic mechanism is not well understood. We report here that mice with hepatocyte-specific knockout (CKO) of Brg1, a chromatin remodeling protein, exhibit reduced levels of hepatic cholesterol compared to the wild type (WT) littermates when placed on a high-fact diet (HFD) or a methionine-and-choline-deficient diet (MCD). Down-regulation of cholesterol levels as a result of BRG1 deficiency was accompanied by attenuation of cholesterogenic gene transcription. Likewise, BRG1 knockdown in hepatocytes markedly suppressed the induction of cholesterogenic genes by lipid depletion formulas. Brg1 interacted with SREBP2 and was recruited by SREBP2 to the cholesterogenic gene promoters. Reciprocally, Brg1 deficiency dampened the occupancies of SREBP2 on target promoters likely through modulating H3K9 methylation on the cholesterogenic gene promoters. Mechanistically, Brg1 recruited the H3K9 methyltransferase KDM3A to co-regulate pro-cholesterogenic transcription. KDM3A silencing dampened the cholesterogenic response in hepatocytes equivalent to Brg1 deficiency. In conclusion, our data demonstrate a novel epigenetic pathway that contributes to SREBP2-dependent cholesterol synthesis in hepatocytes.