SP1-induced upregulation of lncRNA SPRY4-IT1 exerts oncogenic properties by scaffolding EZH2/LSD1/DNMT1 and sponging miR-101-3p in cholangiocarcinoma

A novel hypoxia-induced lncRNA, SZT2-AS1, boosts HCC progression by mediating HIF heterodimerization and histone trimethylation under a hypoxic microenvironment

Hypoxic microenvironment plays a critical role in solid tumor growth, metastasis and angiogenesis. Hypoxia-inducible factors (HIFs), which are canonical transcription factors in response to hypoxia, are stabilized under hypoxia and coordinate the process of hypoxia-induced gene expression, leading to cancer progression. Increasing evidence has uncovered that long noncoding RNAs (lncRNAs), which are closely associated with cancer, play crucial roles in hypoxia-mediated HCC progression, while the mechanisms are largely unknown. Here, we identified SZT2-AS1 as a novel lncRNA in HCC, which was induced by hypoxia in a HIF-1-dependent manner and promoted HCC growth, metastasis and angiogenesis both in vitro and in vivo. And SZT2-AS1 also mediated the hypoxia-induced HCC progression. Clinical data indicated that SZT2-AS1 level was substantially increased in HCC and closely associated with poor clinical outcomes, acting as an independent prognostic predictor. Mechanistically, SZT2-AS1 recruited HIF-1α and HIF-1β to form the HIF-1 heterodimer, and it was required for the occupancy of HIF-1 to hypoxia response elements (HREs) and HIF target gene transcription. In addition, SZT2-AS1 was required for hypoxia-induced histone trimethylation (H3K4me3 and H3K36me3) at HREs. Through recruiting methyltransferase SMYD2, SZT2-AS1 promoted trimethylation of H3K4 and H3K36 in HCC cells. Taken together, our results uncovered a lncRNA-involved positive feedback mechanism under hypoxia and established the clinical value of SZT2-AS1 in prognosis and as a potential therapeutic target in HCC.

Mechanosensitive lncRNA H19 promotes chondrocyte autophagy, but not pyroptosis, by targeting miR-148a in post-traumatic osteoarthritis

OBJECTIVE

Investigating whether mechanosensitive lncRNA H19 can directly target miR-148a to alleviate cartilage damage in post-traumatic osteoarthritis (PTOA).

METHODS

Thirty-two female rats were randomly divided into four groups: Sham-operated group (Sham group, n = 8), treadmill running group (R group, n = 8), anterior cruciate ligament transection (ACLT) group (ACLT group, n = 8), and ACLT + treadmill running group (ACLT + R group, n = 8). Histological evaluation was performed to observe the pathological changes in the cartilage of the rat knee. Micro-CT was performed to detect the bone morphological changes in the subchondral bone. RT-qPCR and Western-Blot were performed to detect changes in mRNA and protein levels of metabolic and inflammatory factors as well as changes in the expression of lncRNA H19 and miR-148a in cartilage. The Flexcell 5000™ Tension System was used to further validate that lncRNA H19 has mechanosensitivity in vitro. Finally, cell transfection techniques were used to knock down the expression of lncRNA H19 in chondrocytes to validate the regulatory role of lncRNA H19/miR-148a in cartilage metabolism.

RESULTS

ACLT combined with treadmill running aggravated the abnormal hyperplasia of subchondral bone in the lateral tibial plateau of the rat knee joint, disturbed the balance of cartilage metabolism, induced cartilage inflammatory response and chondrocyte pyroptosis, which eventually led to cartilage damage and PTOA. Importantly, we found that the expression of lncRNA H19 was significantly downregulated in the cartilage of the ACLT + R group. Bioinformatics analysis revealed that miR-148a may be a direct target of lncRNA H19. Subsequently, we focused on the mechanosensitive of lncRNA H19. Subsequently, moderate-intensity mechanical tension stress reversed the expression of lncRNA H19 and autophagy-related factors in inflammatory chondrocytes, while miR-148a showed an opposite expression trend, demonstrating that mechanosensitive lncRNA H19 may be involved in regulating the chondrocyte inflammatory response by targeting miR-148a and activating autophagy. Cell transfection experiments revealed that lncRNA H19 knockdown upregulated miR-148a expression and significantly inhibited the autophagy level of chondrocytes without significant alteration of chondrocyte pyroptosis, which in turn exacerbated the inflammatory response of chondrocytes.

CONCLUSIONS

Mechanosensitive lncRNA H19 can promote chondrocyte autophagy rather than pyroptosis by targeting miR-148a, thus alleviating cartilage damage in PTOA. LncRNA H19 may be a potential therapeutic target for PTOA.

Alteration of RNA m6A methylation mediates aberrant RNA binding protein expression and alternative splicing in condyloma acuminatum

Background

Condyloma acuminatum (CA) is caused by low-risk human papillomavirus, and is characterized by high recurrence after treatment. The RNA modification N6-methyladenosine (m6A) plays an important role during diverse viral infections, including high-risk HPV infection in cervical cancer. However, it is unclear whether low-risk HPV infection changes the RNA m6A methylation in CA.

Methods

High-throughputm6A-sequencing was performed to profile the transcriptome-wide mRNA modifications of CA tissues infected by LR-HPVs and the paired normal tissues from CA patients. We further investigated the regulation of alternative splicing by RNA binding proteins (RBPs) with altered m6A modification and constructed a regulatory network among these RBPs, regulated alternative splicing events (RASEs) and regulated alternative splicing genes (RASGs) in CA.

Results

The results show that the m6A level in CA tissues differed from that in the paired controls. Furthermore, cell cycle- and cell adhesion- associated genes with m6A modification were differentially expressed in CA tissues compared to the paired controls. In particular, seven RNA binding protein genes with specific m6A methylated sites, showed a higher or lower expression at the mRNA level in CA tissues than in the paired normal tissues. In addition, these differentially expressed RNA binding protein genes would regulate the alternative splicing pattern of apoptotic process genes in CA tissue.

Conclusions

Our study reveals a sophisticated m6A modification profile in CA tissue that affects the response of host cells to HPV infection, and provides cues for the further exploration of the roles of m6A and the development of a novel treatment strategy for CA.

Epigenetic regulation of hepatocellular carcinoma progression: MicroRNAs as therapeutic, diagnostic and prognostic factors

Hepatocellular carcinoma (HCC), a significant challenge for public healthcare systems in developed Western countries including the USA, Canada, and the UK, is influenced by different risk factors including hepatitis virus infections, alcoholism, and smoking. The disruption in the balance of microRNAs (miRNAs) plays a vital function in tumorigenesis, given their function as regulators in numerous signaling networks. These miRNAs, which are mature and active in the cytoplasm, work by reducing the expression of target genes through their impact on mRNAs. MiRNAs are particularly significant in HCC as they regulate key aspects of the tumor, like proliferation and invasion. Additionally, during treatment phases such as chemotherapy and radiotherapy, the levels of miRNAs are key determinants. Pre-clinical experiments have demonstrated that altered miRNA expression contributes to HCC development, metastasis, drug resistance, and radio-resistance, highlighting related molecular pathways and processes like MMPs, EMT, apoptosis, and autophagy. Furthermore, the regulatory role of miRNAs in HCC extends beyond their immediate function, as they are also influenced by other epigenetic factors like lncRNAs and circular RNAs (circRNAs), as discussed in recent reviews. Applying these discoveries in predicting the prognosis of HCC could mark a significant advancement in the therapy of this disease.

Role of long non-coding RNAs in cholangiocarcinoma: A systematic review and meta-analysis

BACKGROUND

Cholangiocarcinoma (CCA), as a rare malignancy of the biliary tree, has a poor prognosis most of the time. CCA is highly epigenetically regulated and several long non-coding RNAs (lncRNA) have been investigated to have a diagnostic and prognostic role in CCA. The current study aimed to assess the studies finding relevant lncRNAs in CCA systematically.

METHODS

International databases, including PubMed, Cochrane Library, and Embase, were comprehensively searched in order to identify studies investigating any lncRNA in CCA. After screening by title/abstract and full-text, necessary data were extracted. Random-effect meta-analysis was performed for pooling the areas under the curve (AUCs), specificity, and sensitivity of lncRNAs for the diagnosis of CCA.

RESULTS

A total of 33 studies were chosen to be included in the final analysis, comprised of 2677 patients. Meta-analysis of AUCs for evaluation of CCA resulted in pooled AUC of 0.79 (95% CI: 0.75-0.82; I2 = 69.11, p < .01). Additionally, overall sensitivity of 0.80 (95% CI 0.75-0.84) and specificity of 0.77 (95% CI: 0.68-0.84) were observed. Measurement of lncRANs in the assessment of CCA also improved overall survival significantly (effect size 1.61, 95% CI: 1.39-1.82). A similar result was found for progression-free survival (effect size 1.57, 95% CI: 1.20-1.93).

CONCLUSION

Based on our findings, lncRNAs showed promising results as biomarkers in the diagnosis of CCA since they had acceptable sensitivity and specificity, in addition to the fact that improved survival in this poor prognosis cancer. Further studies might be needed to address this issue and find the best clinically useful lncRNA.

EZH2 as a potential therapeutic target for gastrointestinal cancers

Gastrointestinal (GI) cancers continue to be a major cause of mortality and morbidity globally. Understanding the molecular pathways associated with cancer progression and severity is essential for creating effective cancer treatments. In cancer research, there is a notable emphasis on Enhancer of zeste homolog 2 (EZH2), a key player in gene expression influenced by its irregular expression and capacity to attach to promoters and alter methylation status. This review explores the impact of EZH2 signaling on various GI cancers, such as colorectal, gastric, pancreatic, hepatocellular, esophageal, and cholangiocarcinoma. The primary function of EZH2 signaling is to facilitate the accelerated progression of cancer cells. Additionally, EZH2 has the capacity to modulate the reaction of GI cancers to chemotherapy and radiotherapy. Numerous pathways, including long non-coding RNAs and microRNAs, serve as upstream regulators of EZH2 in these types of cancer. EZH2's enzymatic activity enables it to attach to target gene promoters, resulting in methylation that modifies their expression. EZH2 could be considered as an independent prognostic factor, with increased expression correlating with a worse disease prognosis. Additionally, a range of gene therapies including small interfering RNA, and anti-tumor agents are being explored to target EZH2 for cancer treatment. This comprehensive review underscores the current insights into EZH2 signaling in gastrointestinal cancers and examines the prospect of therapies targeting EZH2 to enhance patient outcomes.

SP1-Induced Upregulation of LncRNA AFAP1-AS1 Promotes Tumor Progression in Triple-Negative Breast Cancer by Regulating mTOR Pathway

The long non-coding RNA (lncRNA) actin fiber-associated protein-1 antisense RNA 1 (AFAP1-AS1) exerted oncogenic activity in triple-negative breast cancer (TNBC). We designed this study and conducted it to investigate the upstream regulation mechanism of AFAP1-AS1 in TNBC tumorigenesis. In this work, we proved the localization of AFAP1-AS1 in the cytoplasm. We elucidated the mechanism by which the transcription factor specificity protein 1 (SP1) modulated AFAP1-AS1 in TNBC progression, which has yet to be thoroughly studied. Dual luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay revealed a strong affinity of SP1 toward the promoter regions P3 of AFAP1-AS1, proving the gene expression regulation of AFAP1-AS1 via SP1 in TNBC. Additionally, SP1 could facilitate the tumorigenesis of TNBC cells in vitro and in vivo by regulating the AFAP1-AS1 expression. Furthermore, silenced AFAP1-AS1 suppressed the expression of genes in the mTOR pathway, such as eukaryotic translation initiation factor 4B (EIF4B), mitogen-activated protein kinase-associated protein 1 (MAPKAP1), SEH1-like nucleoporin (SEH1L), serum/glucocorticoid regulated kinase 1 (SGK1), and its target NEDD4-like E3 ubiquitin protein ligase (NEDD4L), and promoted the gene expression of s-phase kinase-associated protein 2 (SKP2). Overall, this study emphasized the oncogenic role of SP1 and AFAP1-AS1 in TNBC and illustrated the AFAP1-AS1 upstream interaction with SP1 and the downstream modulatory of mTOR signaling, thus offering insights into the tumorigenesis mechanism in TNBC.

The interactions between DNA methylation machinery and long non-coding RNAs in tumor progression and drug resistance

DNA methylation is one of the main epigenetic mechanisms in cancer development and progression. Aberrant DNA methylation of CpG islands within promoter regions contributes to the dysregulation of various tumor suppressors and oncogenes; this leads to the appearance of malignant features, including rapid proliferation, metastasis, stemness, and drug resistance. The discovery of two important protein families, DNA methyltransferases (DNMTs) and Ten-eleven translocation (TET) dioxygenases, respectively, which are responsible for deregulated transcription of genes that play pivotal roles in tumorigenesis, led to further understanding of DNA methylation-related pathways. But how these enzymes can target specific genes in different malignancies; recent studies have highlighted the considerable role of Long Non-coding RNAs (LncRNAs). LncRNAs recruit these enzymes to promoter regions of genes and mediate their functions, showing great potential as therapeutic agents targeting the epigenetic regulation of various genes. Considering the importance of combining the current treatment methods, especially chemotherapies, with DNA methylation inhibitors in improving patients' outcomes, this review aimed to summarize the recent findings about the interaction between DNA methylation machinery and LncRNAs in regulating genes involved in tumorigenesis and drug resistance. So, these studies could provide insights toward developing novel strategies for cancer-targeted therapy.

A review on the role of ncRNAs in the pathogenesis of cholangiocarcinoma

Cholangiocarcinoma is a rare tumor but a challenging cancer in terms of pathological changes, clinical manifestations and therapeutic options. Recent studies have provided evidence for participation of non-coding RNAs in the carcinogenic process of cholangiocarcinoma. We demonstrate the role of long non-coding RNAs, microRNAs and circular RNAs in the pathogenesis of cholangiocarcinoma and highlight their significant position as therapeutic targets and biomarkers for this type of cancer. We also list a number of molecular axes comprising these non-coding RNAs that represent potential targets for therapeutic options in cholangiocarcinoma, based on their significant roles in the regulation of cell proliferation, differentiation and apoptosis of these cells.

LncRNA SPRY4‐IT1 facilitates cell proliferation and angiogenesis of glioma via the miR‐101‐3p/EZH2/VEGFA signaling axis

BACKGROUND

SPRY4-IT1 (SPRY4 intronic transcript 1) is a long non-coding RNA (lncRNA) that has been identified as a novel oncogene in various cancers, including glioma. However, its function and underlying mechanism in glioma remain largely unclear. Here, we investigated the role of SPRY4-IT1 in the development of glioma and its underlying mechanism.

METHODS

Bioinformatics analysis and RT-qPCR assay were used to examine the expression of SPRY4-IT1 in glioma tissues. The CCK-8, EdU, and Xenograft tumor assays wereperformed to assess the proliferation effect of glioma cells. The tube forming assay and Chick Embryo Chorioallantoic Membrane (CAM) assay were conducted to detect the angiogenesis effect of HUVECs. RNA-sequencing, western blotting, RT-qPCR, ELISA, and IHC assays were employed to verify the regulatory mechanism of the SPRY4-IT1/ miR-101-3p/EZH2/VEGFA axis.

RESULTS

Analysis of the TCGA dataset and data from our own cohort demonstrated that SPRY4-IT1 was overexpressed in patients with glioma, and high SPRY4-IT1 expression correlated with poor prognosis. In vitro and in vivo experiments showed that SPRY4-IT1 promoted the proliferation of glioma cells. RNA sequencing and Gene Ontology (GO) enrichment analysis indicated significant enrichment of angiogenesis. HUVEC tube forming assay and CAM assay confirmed that SPRY4-IT1 could induce angiogenesis of glioma cells in vitro and in vivo. Mechanistically, SPRY4-IT1 upregulated EZH2 expression by sponging miR-101-3p to induce VEGFA expression in glioma cells. Moreover, SPRY4-IT1 activated the VEGFR2/AKT/ERK1/2 pathway in HUVECs mediated by glioma cells. Rescue experiments further confirmed that SPRY4-IT1 promoted glioma cell proliferation and angiogenesis via the miR-101-3p/EZH2/VEGFA signaling axis.

CONCLUSIONS

Our findings provide compelling evidence showing that SPRY4-IT1 upregulated EZH2 to induce VEGFA by sponging miR-101-3p, thereby achieving cell proliferation and angiogenesis in glioma. Therefore, targeting SPRY4-IT1/miR-101-3p/EZH2/VEGFA axis may improve the outcomes of patients with glioma.

LINC02535/miR-30a-5p/GALNT3 axis contributes to lung adenocarcinoma progression via the NF- κ B signaling pathway

Long non-coding RNAs (LncRNA) play important roles in multiple types of cancers. We addressed the role of LINC02535 by regulating the miR-30a-5p /GalNAc Transferase 3 (GALNT3) axis to promote the proliferation, migration, and invasion in lung adenocarcinoma (LUAD) cells. The Cancer Genome Atlas (TCGA) database screened differentially expressed lncRNAs. Quantitative real-time PCR analysis (qRT-PCR) confirmed that LINC02535 is highly expressed in LUAD tissues and cells. In vitro experiments showed that LINC02535 promotes the proliferation, migration, and invasion of LUAD cells. A xenograft mouse model was used to show that LINC02535 promotes tumor growth in vivo. RNA immunoprecipitation (RIP) and Dual-luciferase reporter assay results confirmed that LINC02535 targets miR-30a-5p. The Vicia villosa lectin (VVA) pull-down assay indicated that MUC1 is the glycosylation target of GALNT3, and western blot verified that NF-κB is the downstream signaling pathway of MUC1. We found that LINC02535 was increased in LUAD tissues and cells, and LINC02535 was correlated with the poor prognosis of LUAD patients. miR-30a-5p acts as a tumor suppressor in LUAD by targeting GALNT3. We also demonstrated that LINC02535 might function as the sponge of miR-30a-5p to up-regulate GALNT3, and consequently promote the proliferation and metastasis of LUAD. LINC02535 acts as a competing endogenous RNA (ceRNA) to interact with miR-30a-5p, thereby upregulating the expression of GALNT3, enhancing the function of MUC1, and activating the NF-κB signaling pathway, promoting the malignant progression of LUAD cells.Abbreviations: LncRNA:long non-coding RNA; LUAD: lung adenocarcinoma; TCGA: The Cancer Genome Atlas; GALNT3: GalNAc Transferase 3; qRT-PCR: quantitative real-time PCR analysis; RIP: RNA immunoprecipitation; SPF: specific pathogen-free; VVA: Vicia villosa lectin; ceRNA: competing endogenous RNA; MiRNAs: microRNAs; FBS: fetal bovine serum; PBS: Phosphate buffered saline; CCK-8: Cell Counting Kit-8; NSCLC: non-small cell lung cancer; OC: ovarian cancer; HCC: hepatocellular carcinoma.

JUND/linc00976 promotes cholangiocarcinoma progression and metastasis, inhibits ferroptosis by regulating the miR-3202/GPX4 axis

Long noncoding RNAs (lncRNAs) are a novel class of noncoding RNAs that have emerged as critical regulators and biomarkers in various cancers. Nevertheless, the expression profile and mechanistic function of lncRNAs in cholangiocarcinoma (CCA) remain unclear. Herein, we examined the expression levels of linc00976 in clinical specimens and cell lines using reverse transcription-quantitative PCR. In total, 50 patients with CCA were enrolled to analyze the correlation between linc00976 expression and clinical characteristics of CCA. Loss- and gain-of-function experiments were performed to investigate the biological effects of linc00976 on proliferation, ferroptosis, migration, and invasion of CCA cells in vitro and in vivo. In situ hybridization, RNA immunoprecipitation, bioinformatic databases, RNA pull-down assay, a dual-luciferase reporter assay, mRNA sequencing, chromatin immunoprecipitation-PCR, and rescue experiments were performed to elucidate the underlying mechanisms of linc00976-induced competitive endogenous RNA regulatory networks. We characterized a novel and abundant lncRNA, linc00976, that functions as a pro-oncogenic regulator of CCA progression. Compared with normal controls, linc00976 was dramatically upregulated in CCA tissue samples and cell lines. Patients with CCA exhibiting high linc00976 expression had a highly advanced clinical stage, substantial lymph node metastasis, and poor overall survival. Knockdown of linc00976 significantly repressed proliferation and metastasis and promoted ferroptosis of CCA cells both in vitro and in vivo, whereas linc00976 overexpression exerted the opposite effect. Mechanistically, linc00976 competitively interacted with miR-3202 to upregulate GPX4 expression, thus contributing to the malignant biological behavior of CCA cells. Moreover, we demonstrated that JUND specifically interacts with the linc00976 promoter and activates linc00976 transcription. Accordingly, JUND promotes linc00976 transcription, and linc00976 plays a crucial role in accelerating CCA tumorigenesis and metastasis and inhibiting ferroptosis by modulating the miR-3202/GPX4 axis. These findings suggest that targeting linc00976 may afford a promising therapeutic strategy for patients with CCA.

Exploring the Novel Computational Drug Target and Associated Key Pathways of Oral Cancer

Oral cancer (OC) is a serious health concern that has a high fatality rate. The oral cavity has seven kinds of OC, including the lip, tongue, and floor of the mouth, as well as the buccal, hard palate, alveolar, retromolar trigone, and soft palate. The goal of this study is to look into new biomarkers and important pathways that might be used as diagnostic biomarkers and therapeutic candidates in OC. The publicly available repository the Gene Expression Omnibus (GEO) was to the source for the collection of OC-related datasets. GSE74530, GSE23558, and GSE3524 microarray datasets were collected for analysis. Minimum cut-off criteria of |log fold-change (FC)| > 1 and adjusted p < 0.05 were applied to calculate the upregulated and downregulated differential expression genes (DEGs) from the three datasets. After that only common DEGs in all three datasets were collected to apply further analysis. Gene ontology (GO) and pathway analysis were implemented to explore the functional behaviors of DEGs. Then protein−protein interaction (PPI) networks were built to identify the most active genes, and a clustering algorithm was also implemented to identify complex parts of PPI. TF-miRNA networks were also constructed to study OC-associated DEGs in-depth. Finally, top gene performers from PPI networks were used to apply drug signature analysis. After applying filtration and cut-off criteria, 2508, 3377, and 670 DEGs were found for GSE74530, GSE23558, and GSE3524 respectively, and 166 common DEGs were found in every dataset. The GO annotation remarks that most of the DEGs were associated with the terms of type I interferon signaling pathway. The pathways of KEGG reported that the common DEGs are related to the cell cycle and influenza A. The PPI network holds 88 nodes and 492 edges, and CDC6 had the highest number of connections. Four clusters were identified from the PPI. Drug signatures doxorubicin and resveratrol showed high significance according to the hub genes. We anticipate that our bioinformatics research will aid in the definition of OC pathophysiology and the development of new therapies for OC.

Long non-coding RNAs in the pathogenesis of heart failure: A literature review

Heart failure (HF) is a common cardiovascular disorder and a major cause of mortality and morbidity in older people. The mechanisms underlying HF are still not fully understood, restricting novel therapeutic target discovery and drug development. Besides, few drugs have been shown to improve the survival of HF patients. Increasing evidence suggests that long non-coding RNAs (lncRNAs) serve as a critical regulator of cardiac physiological and pathological processes, regarded as a new target of treatment for HF. lncRNAs are versatile players in the pathogenesis of HF. They can interact with chromatin, protein, RNA, or DNA, thereby modulating chromatin accessibility, gene expressions, and signaling transduction. In this review, we summarized the current knowledge on how lncRNAs involve in HF and categorized them into four aspects based on their biological functions, namely, cardiomyocyte contractility, cardiac hypertrophy, cardiac apoptosis, and myocardial fibrosis. Along with the extensive laboratory data, RNA-based therapeutics achieved great advances in recent years. These indicate that targeting lncRNAs in the treatment of HF may provide new strategies and address the unmet clinical needs.

Epigenetic deregulation in cancer: Enzyme players and non-coding RNAs

Data obtained from cutting-edge research have shown that deregulated epigenetic marks are critical hallmarks of cancer. Rapidly emerging scientific evidence has helped in developing a proper understanding of the mechanisms leading to control of cellular functions, from changes in chromatin accessibility, transcription and translation, and in post-translational modifications. Firstly, mechanisms of DNA methylation and demethylation are introduced, as well as modifications of DNA and RNA, with particular focus on N6-methyladenosine (m6A), discussing the effects of these modifications in normal cells and in malignancies. Then, chromatin modifying proteins and remodelling complexes are discussed. Many enzymes and accessory proteins in these complexes have been found mutated or have undergone differential splicing, leading to defective protein complexes. Epigenetic mechanisms acting on nucleosomes by polycomb repressive complexes and on chromatin by SWI/SNF complexes on nucleosome assembly/disassembly, as well as main mutated genes linked to cancers, are reviewed. Among enzymes acting on histones and other proteins erasing the reversible modifications are histone deacetylases (HDACs). Sirtuins are of interest since most of these enzymes not only deacylate histones and other proteins, but also post-translationally modify proteins adding a Mono-ADP-ribose (MAR) moiety. MAR can be read by MACRO-domain containing proteins such as histone MacroH2A1, with specific function in chromatin assembly. Finally, recent advances are presented on non-coding RNAs with a scaffold function, prospecting their role in assembly of chromatin modifying complexes, recruiting enzyme players to chromatin regions. Lastly, the imbalance in metabolites production due to mitochondrial dysfunction is presented, with the potential of these metabolites to inhibit enzymes, either writers, readers or erasers of epitranscriptome marks. In the perspectives, studies are overwied on drugs under development aiming to limit excessive enzyme activities and to reactivate chromatin modifying complexes, for therapeutic application. This knowledge may lead to novel drugs and personalised medicine for cancer patients.

Linc00883 affects colorectal cancer through miR-577/FKBP14 axis: a novel mechanism for regulating colorectal cancer cell proliferation, invasion, and migration

Long non-coding RNAs (lncRNAs) are relevant to the development of human cancers. Here, we aimed to investigate the role and mechanism of Linc00883 in the proliferation, invasion, and migration of colorectal cancer (CRC) cells. CRC cell lines SW480 and LoVo were applied as in vitro models in this study. Quantitative real-time PCR was applied to measure Linc00883, miR-577, and FKBP14 expressions. Cell Counting Kit-8, transwell, and wound-healing assays were carried out to confirm the function of Linc00883. Western blot was applied to detect the protein levels of the epithelial-mesenchymal transition-related proteins E-cadherin, vimentin, fibronectin, and α-SMA. RNA immunoprecipitation (RIP) and RNA pull-down experiments were performed to confirm the relationship between Linc00883 and miR-577. Linc00883 expression was elevated in CRC tissues and cells, and the patients with high expression of Linc00883 were related to a low survival rate and prone to distant metastasis. Moreover, we corroborated that Linc00883 and miR-577, miR-577 and FKBP14 are bound to each other. Linc00883 was negatively correlated with miR-577, and miR-577 was also negatively correlated with FKBP14. Furthermore, interference with Linc00883 restrained the proliferation, invasion, and migration of CRC cells through the miR-577/FKBP14 axis. In vivo studies also clarified that Linc00883 facilitated the growth of CRC tumors and the epithelial-mesenchymal transition (EMT) of CRC. Our results demonstrated that Linc00883 facilitated the proliferation, invasion, and migration of CRC cells by regulating the miR-577/FKBP14 axis.

Long Non-Coding RNAs as Molecular Biomarkers in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a biliary system cancer that has the characteristics of strong invasiveness, poor prognosis, and few therapy choices. Furthermore, the absence of precise biomarkers for early identification and prognosis makes it hard to intervene in the early phase of initial diagnosis or recurring cholangiocarcinoma following surgery. Encouragingly, previous studies found that long non-coding RNA (lncRNA), a subgroup of RNA that is more than 200 nucleotides long, can affect cell proliferation, migration, apoptosis, and even drug resistance by altering numerous signaling pathways, thus reaching pro-cancer or anti-cancer outcomes. This review will take a retrospective view of the recent investigations on the work of lncRNAs in cholangiocarcinoma progression and the potential of lncRNAs serving as promising clinical biomarkers and therapeutic targets for CCA.

The long and short non-coding RNAs modulating EZH2 signaling in cancer

Non-coding RNAs (ncRNAs) are a large family of RNA molecules with no capability in encoding proteins. However, they participate in developmental and biological processes and their abnormal expression affects cancer progression. These RNA molecules can function as upstream mediators of different signaling pathways and enhancer of zeste homolog 2 (EZH2) is among them. Briefly, EZH2 belongs to PRCs family and can exert functional roles in cells due to its methyltransferase activity. EZH2 affects gene expression via inducing H3K27me3. In the present review, our aim is to provide a mechanistic discussion of ncRNAs role in regulating EZH2 expression in different cancers. MiRNAs can dually induce/inhibit EZH2 in cancer cells to affect downstream targets such as Wnt, STAT3 and EMT. Furthermore, miRNAs can regulate therapy response of cancer cells via affecting EZH2 signaling. It is noteworthy that EZH2 can reduce miRNA expression by binding to promoter and exerting its methyltransferase activity. Small-interfering RNA (siRNA) and short-hairpin RNA (shRNA) are synthetic, short ncRNAs capable of reducing EZH2 expression and suppressing cancer progression. LncRNAs mainly regulate EZH2 expression via targeting miRNAs. Furthermore, lncRNAs induce EZH2 by modulating miRNA expression. Circular RNAs (CircRNAs), like lncRNAs, affect EZH2 expression via targeting miRNAs. These areas are discussed in the present review with a focus on molecular pathways leading to clinical translation.

A Review on the Role of SPRY4-IT1 in the Carcinogenesis

Sprouty RTK signaling antagonist 4-intronic transcript 1 (SPRY4-IT1) is a long non-coding RNA (lncRNA) encoded by a gene located on 5q31.3. This lncRNA has a possible role in the regulation of cell growth, proliferation, and apoptosis. Moreover, since SPRY4-IT1 controls levels of lipin 2, it is also involved in the biosynthesis of lipids. During the process of biogenesis, SPRY4-IT1 is produced as a primary transcript which is then cleaved to generate a mature transcript which is localized in the cytoplasm. SPRY4-IT1 has oncogenic roles in diverse tissues. A possible route of participation of SPRY4-IT1 in the carcinogenesis is through sequestering miRNAs such as miR-101-3p, miR-6882-3p and miR-22-3p. The sponging effect of SPRY4-IT1 on miR-101 has been verified in colorectal cancer, osteosarcoma, cervical cancer, bladder cancer, gastric cancer and cholangiocarcinoma. SPRY4-IT1 has functional interactions with HIF-1α, NF-κB/p65, AMPK, ZEB1, MAPK and PI3K/Akt signaling. We explain the role of SPRY4-IT1 in the carcinogenesis according to evidence obtained from cell lines, xenograft models and clinical studies.

microRNA-124-3p attenuates myocardial injury in sepsis via modulating SP1/HDAC4/HIF-1α axis

Sepsis-induced cardiac dysfunction can lead to death in sepsis. In this case, we targeted to explore in detail the relative mechanism of microRNA (miR)-124-3p in sepsis-induced myocardial injury via the specific protein 1/histone deacetylase 4/hypoxia-inducing factor 1α (SP1/HDAC4/HIF-1α) axis. Septic rats were modeled by cecal ligation puncture while in vitro septic cardiomyocyte H9C2 were induced by lipopolysaccharide (LPS). miR-124-3p/SP1/HDAC4/HIF-1α expression levels in myocardial tissues of septic rats and LPS-treated H9C2 cells were measured. miR-124-3p overexpression and SP1 silencing assays were implemented on LPS-treated H9C2 cells to explore theirs actions in inflammation, oxidative stress and cell apoptosis. The interactions of miR-124-3p, SP1, and HDAC4 were testified. miR-124-3p was lowly expressed while SP1, HDAC4, and HIF-1α were highly expressed in sepsis. Upregulation of miR-124-3p ameliorated inflammation, oxidative stress, and apoptosis of LPS-treated H9C2 cells. Silencing SP1 improved LPS-induced damage to cardiomyocytes. miR-124-3p targeted SP1 and HDAC4 interacted with SP1. SP1 overexpression antagonized miR-124-3p upregulation-induced improvements in LPS-induced cardiomyocyte damage. This study illustrates that miR-124-3p improves myocardial injury in septic rats through targeted regulation of SP1 to mediate HDAC4/HIF-1α.

Intricate crosstalk between MYB and noncoding RNAs in cancer

MYB is often overexpressed in malignant tumors and plays a carcinogenic role in the initiation and development of cancer. Deletion of the MYB regulatory C-terminal domain may be a driving mutation leading to tumorigenesis, therefore, different tumor mechanisms produce similar MYB proteins. As MYB is a transcription factor, priority has been given to identifying the genes that it regulates. All previous attention has been focused on protein-coding genes. However, an increasing number of studies have suggested that MYB can affect the complexity of cancer progression by regulating tumor-associated noncoding RNAs (ncRNAs), such as microRNAs, long-non-coding RNAs and circular RNAs. ncRNAs can regulate the expression of numerous downstream genes at the transcription, RNA processing and translation levels, thereby having various biological functions. Additionally, ncRNAs play important roles in regulating MYB expression. This review focuses on the intricate crosstalk between oncogenic MYB and ncRNAs, which play a pivotal role in tumorigenesis, including proliferation, apoptosis, angiogenesis, metastasis, senescence and drug resistance. In addition, we discuss therapeutic strategies for crosstalk between MYB and ncRNAs to prevent the occurrence and development of cancer.

LncRNA SNHG1 promotes tumor progression and cisplatin resistance through epigenetically silencing miR-381 in breast cancer

The long-non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) is a known cause of tumorigenesis. Nevertheless, it’s yet unclear how lncRNA SNHG1 influences breast cancer. Herein, we explored the mechanisms through which SNHG1 modulates breast cancer tumor progression. Our findings demonstrated that SNHG1 is significantly upregulated in breast cancer tissues and cells. High SNHG1 levels were closely linked to reduced survival rates in breast cancer patients. SNHG1 silencing has been shown to inhibit the proliferative, migratory, and invasive activity of breast cancer cells. Moreover, SNHG1 silencing enhanced cisplatin (DDP) sensitivity of these cells through improving DDP-induced cell apoptosis. Mechanistically, SNHG1 was found to interact with enhancer of zeste homolog 2 (EZH2), recruiting EZH2 to trigger trimethylation of histone H3 lysine 27 (H3K27me3), thus epigenetically inhibiting miR-381 transcription in these cells. Overexpression of miR-381 inhibited tumor progression and sensitized cells to the chemotherapeutic reagent DDP. More importantly, rescue experiments demonstrated that miR-381 inhibition could inverse the tumor-suppressive effect of SNHG1 silencing in breast cancer. In summary, SNHG1 silencing suppressed tumor progression and overcame breast cancer cell DDP resistance via the epigenetic suppression of miR-381 expression. Our study revealed that SNHG1 served as a novel therapeutic target for breast cancer chemoresistance.

Long non-coding RNA SNHG22 facilitates hepatocellular carcinoma tumorigenesis and angiogenesis via DNA methylation of microRNA miR-16-5p

Hepatocellular carcinoma (HCC) is considered as a common malignancy worldwide. Considerable evidence has illustrated that abnormally expressed long noncoding RNAs (lncRNAs) are in a close correlation with the initiation and progression of various tumors, including HCC. LncRNA small nucleolar RNA host gene 22 (SNHG22) has been reported to play important roles in tumor initiation, but its role and mechanism are little known in HCC. In our report, we discovered the high level of SNHG22 in HCC tissues and cells, and the high expression of SNHG22 was correlated with unfavorable clinical outcome in HCC patients. Functional assays implied that SNHG22 deficiency suppressed cell proliferation, migration, invasion, and angiogenesis in vitro. Additionally, it was also confirmed that silenced SNHG22 suppressed tumor growth and angiogenesis in vivo. Mechanistic exploration revealed that SNHG22 recruited DNMT1 to miR-16-5p DNA promoter through EZH2 and inhibited miR-16-5p transcription via DNA methylation. Finally, we verified that the suppression of miR-16-5p countervailed the suppressive effect of SNHG22 deficiency on HCC cell proliferation, migration, invasion, and angiogenesis. Conclusively, this study clarified the SNHG22/EZH2/DNMT1/miR-16-5p axis and revealed that SNHG22 could be an underlying biomarker for HCC.

Protein profiling reveals potential isomiR-associated cross-talks among RNAs in cholangiocarcinoma

Cholangiocarcinomas (CCAs) are tumors that arise from the cholangiocytes. Although some genes have been shown with important roles in pathological process, interactions or cross-talks among different RNAs are important to understand the detailed molecular mechanisms in cancer development, especially discussing cross-talks among isomiRs and other RNAs. Herein, to characterize crucial genes in CCA, the protein expression profile was performed to survey potential crucial mRNAs and related non-coding RNAs (ncRNAs) in mRNA-ncRNA network, mainly including miRNAs/isomiRs and lncRNAs. Deregulated mRNAs were firstly obtained if consistent expression patterns were found at protein and mRNA levels, and related miRNAs/isomiRs were screened according to regulatory relationships. Diverse isomiRs from a given miRNA locus also contributed to interactions between the small RNAs and target mRNAs, and miRNAs were further used to survey related lncRNAs to expand the interactions. Thus, several groups of RNAs were constructed as candidate competitive endogenous RNA (ceRNA) networks. Finally, we found that RAB11FIP1:miR-101-3p:MIR3142HG may be a potential ceRNA network, and the interactions among them may be more complex due to variety of isomiRs. Simultaneously, RAB11FIP1 and miR-194-5p were also detected other related lncRNAs (FBXL19-AS1, SNHG1 and PVT1) that may be crucial in coding-non-coding RNA regulatory network. Our results show that diverse isomiRs with sequence and expression heterogeneities contribute to ceRNA regulatory network that may have crucial roles in CCA, which will expand our understanding of interactions among diverse RNAs and their contributions in cancer development.

SP1-Regulated Non-Coding RNA SNHG22 Promotes Ovarian Cancer Growth and Glycolysis

Objectives

Long non-coding RNAs (lncRNAs) play a crucial part in cancer progression. However, in epithelial ovarian carcinoma (EOC), the role of SNHG22 needs to be further explained.

Methods

Quantitative real-time PCR was used to detect the expression of SNHG22. EOC cells were stably transfected with lentivirus approach and cell proliferation, glycolysis and cell apoptosis, as well as tumorigenesis in animal were performed to assess the effects of SNHG22 in EOC. Chromatin immunoprecipitation (ChIP) and luciferase reporter assay were conducted to confirm the relationship between SP1 and SNHG22.

Results

Higher expressed SNHG22 was associated with a poor prognosis in EOC tissues. SNHG22 facilitated glycolysis and proliferation. Mechanistically, LDHA deficiency and glycolysis inhibitor (2-DG, 3-BG) partly rescued proliferation. SP1 mediated SNHG22 expression at the transcriptional level and the SNHG22 promoter region (−900~ −600) was necessary for SP1 binding. Hypoxia and HIF-1α also upregulated SNHG22 expression.

Conclusion

SNHG22 is an independent prognostic biomarker for EOC. SNHG22 promotes EOC progression and is a prospective therapeutic target.

Cholangiocarcinoma and liver transplantation: What we know so far?

Cholangiocarcinoma (CCA) is a type of cancer with increasing prevalence around the world that originates from cholangiocytes, the epithelial cells of the bile duct. The tumor begins insidiously and is distinguished by high grade neoplasm, poor outcome, and high risk for recurrence. Liver transplantation has become broadly accepted as a treatment option for CCA. Liver transplantation is expected to play a crucial role as palliative and curative therapy for unresectable hilar CCA and intrahepatic CCA. The purpose of this study was to determine which cases with CCA should be subjected to liver transplantation instead of resection, although reported post-transplant recurrence rate averages approximately 20%. This review also aims to highlight the molecular current frontiers of CCA and directions of liver transplantation for CCA.

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.

The Role of microRNAs in Cholangiocarcinoma

Cholangiocarcinoma (CCA), an aggressive malignancy, is typically diagnosed at an advanced stage. It is associated with dismal 5-year postoperative survival rates, generating an urgent need for prognostic and diagnostic biomarkers. MicroRNAs (miRNAs) are a class of non-coding RNAs that are associated with cancer regulation, including modulation of cell cycle progression, apoptosis, metastasis, angiogenesis, autophagy, therapy resistance, and epithelial–mesenchymal transition. Several miRNAs have been found to be dysregulated in CCA and are associated with CCA-related risk factors. Accumulating studies have indicated that the expression of altered miRNAs could act as oncogenic or suppressor miRNAs in the development and progression of CCA and contribute to clinical diagnosis and prognosis prediction as potential biomarkers. Furthermore, miRNAs and their target genes also contribute to targeted therapy development and aid in the determination of drug resistance mechanisms. This review aims to summarize the roles of miRNAs in the pathogenesis of CCA, their potential use as biomarkers of diagnosis and prognosis, and their utilization as novel therapeutic targets in CCA.

The promotion of cervical cancer progression by signal transducer and activator of transcription 1-induced up-regulation of lncRNA MEOX2-AS1 as a competing endogenous RNA through miR-143-3p/VDAC1 pathway

Long non-coding RNAs (lncRNAs) are the new regulators and biomarkers for various tumors. However, in cervical cancer (CC), the potential roles of lncRNAs are not well characterized. This research aimed at exploring the roles of MEOX2 antisense RNA 1(MEOX2-AS1) in CC progression and the underlying mechanisms. The examination of MEOX2-AS1 levels in CC specimens and cell lines was conducted by RT-PCR. Loss-of-function experiments were performed for the assays of proliferation, migration, and invasion of CC cells after various treatments. Animal experiments were applied for the determination of the effects of MEOX2-AS1 in vivo. Bioinformatics analysis, together with dual-luciferase reporter assays, was applied to demonstrate the possible relationships among MEOX2-AS1, miR-143-3p and VDAC1. In the paper, we reported that MEOX2-AS1 levels were distinctly upregulated in CC cells and tissues, and higher MEOX2-AS1 expressions indicated a poor clinical outcome. Besides, STAT1 could activate transcriptions of MEOX2-AS1 by binding directly to its promoter region. The silence of MEOX2-AS1 suppressed the metastatic and proliferative ability of CC cells, as revealed by functional assays. Mechanistically, MEOX2-AS1 sponged miR-143-3p to regulate VDAC1 expressions. Furthermore, miR-143-3p inhibitor reversed the anti-proliferation and anti-metastasis effect of MEOX2-AS1 knockdown. Overall, the data indicated that the MEOX2-AS1/miR-143-3p/VDAC1 pathway participated in CC progression, making it a novel therapeutic target for CC cures.

NF-κB-activated SPRY4-IT1 promotes cancer cell metastasis by downregulating TCEB1 mRNA via Staufen1-mediated mRNA decay

Previous study demonstrated that most long non-coding RNAs (lncRNAs) function as competing endogenous RNAs or molecular sponges to negatively modulate miRNA and regulate tumor development. However, the molecular mechanisms of lncRNAs in cancer are not fully understood. Our study describes the role of the lncRNA SPRY4 intronic transcript 1 (SPRY4-IT1) in cancer metastasis by mechanisms related to Staufen1 (STAU1)-mediated mRNA decay (SMD). Briefly, we found that, high SPRY4-IT1 expression was associated with aggressiveness and poor outcome in human colorectal, breast and ovarian cancer tissues. In addition, functional assays revealed that SPRY4-IT1 significantly promoted colorectal, breast and ovarian cancer metastasis in vitro and in vivo. Mechanistically, microarray analyses identified several differentially-expressed genes upon SPRY4-IT1 overexpression in HCT 116 colorectal cancer cells. Among them, the 3'-UTR of transcription elongation factor B subunit 1 (TCEB1) mRNA can base-pair with the Alu element in the 3'-UTR of SPRY4-IT1. Moreover, SPRY4-IT1 was found to bind STAU1, promote STAU1 recruitment to the 3'-UTR of TCEB1 mRNA, and affect TCEB1 mRNA stability and expression, resulting in hypoxia-inducible factor 1α (HIF-1α) upregulation, and thereby affecting cancer cell metastasis. In addition, STAU1 depletion abrogated TCEB1 SMD and alleviated the pro-metastatic effect of SPRY4-IT1 overexpression. Significantly, we revealed that SPRY4-IT1 is also transactivated by NF-κB/p65, which activates SPRY4-IT1 to inhibit TCEB1 expression, and subsequently upregulate HIF-1α. In conclusion, our results highlight a novel mechanism of cytoplasmic lncRNA SPRY4-IT1 in which SPRY4-IT1 affecting TCEB1 mRNA stability via STAU1-mediated degradation during cancer metastasis.

Long noncoding RNA AFAP1-AS1 promotes tumor progression and invasion by regulating the miR-2110/Sp1 axis in triple-negative breast cancer

Long noncoding ribonucleic acids (LncRNAs) have been found to be involved in the proliferation, apoptosis, invasion, migration, and other pathological processes of triple-negative breast cancer (TNBC). Expression of the lncRNA actin filament-associated protein 1 antisense RNA1 (AFAP1-AS1) has been found to be significantly higher in TNBC than in other subtypes or in normal tissue samples, but the specific mechanism by which AFAP1-AS1 affects the occurrence and development of TNBC is yet to be revealed. In this study, we used Cell Counting Kit-8 (CCK-8), colony formation, wound healing migration, Transwell invasion, and nude mouse xenograft assays to confirm the role of AFAP1-AS1 in the proliferation, migration of TNBC cells in vitro and in vivo. In addition, we performed bioinformatics analyses, reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), western blot (WB), and dual-luciferase reporter assays (dual-LRA) to confirm interaction among AFAP1-AS1, micro-RNA 2110 (miR-2110), and Sp1 transcription factor (Sp1). We found that silencing AFAP1-AS1 and Sp1 or upregulating miR-2110 suppressed the proliferation, migration, and invasion of MDA-MB-231 and MDA-MB-468 cells in vitro as well as tumor growth in vivo. Mechanistically, the dual-LRA highlighted that miR-2110 was an inhibitory target of AFAP1-AS1, and that AFAP1-AS1 functioned as a miR-2110 sponge to increase Sp1 expression. AFAP1-AS1 silencing led to a reduction in Sp1 mRNA and protein levels, which could be reversed by joint transfection with miR-2110 inhibitor. Our findings demonstrated that AFAP1-AS1 could modulate the progression of breast cancer cells and affect tumorigenesis in mice by acting as a miR-2110 sponge, resulting in regulation of Sp1 expression. Therefore, AFAP1-AS1 could play a pivotal role in the treatment of TNBC.

Overexpression of lncRNA TUG1 Alleviates NLRP3 Inflammasome-Mediated Cardiomyocyte Pyroptosis Through Targeting the miR-186-5p/XIAP Axis in Coronary Microembolization-Induced Myocardial Damage

Coronary microembolization (CME) is a complicated problem that commonly arises in the context of coronary angioplasty. The lncRNA taurine-up regulated gene 1 (TUG1), significantly contributes to cardiovascular diseases; however, its contribution to CME-induced myocardial damage remains elusive. Herein, we establish the rat CME model and investigate the role of TUG1 in CME. The cell viability was evaluated via CCK-8 assay. Serum and cell culture supernatant samples were evaluated via ELISA. The dual luciferase reporter (DLR) assay, RIP, and RNA-pull down were conducted to validate the associations between TUG1 and miR-186-5p as well as miR-186-5p and XIAP. The expression of TUG1, miR-186-5p, and XIAP mRNA were determined by RT-qPCR, and proteins were evaluated via immuneblotting. As a result, TUG1 and XIAP were significantly down-regulated, and the miR-186-5p level was found to be remarkably up-regulated in CME myocardial tissues. Overexpression of TUG1 alleviated CME-induced myocardial injury and pyroptosis, whereas TUG1 knockdown showed the opposite effects. The DLR assay, RIP, and RNA-pull down results reveal that TUG1 directly targets miR-186-5p and miR-186-5p directly targets XIAP. In vitro rescue experiments show that TUG1 overexpression alleviates LPS-caused cardiomyocyte injury and pyroptosis via sponging miR-186-5p and regulating XIAP, and depression of miR-186-5p reduces LPS-induced cardiomyocyte injury and pyroptosis by targeting XIAP. Concludingly, the overexpression of TUG1 alleviates NLRP3 inflammasome-mediated cardiomyocyte pyroptosis through targeting the miR-186-5p/XIAP axis in CME-induced myocardial injury.

Long Noncoding RNA SPRY4-IT1 Modulates Ketamine-Induced Neurotoxicity in Human Embryonic Stem Cell-Derived Neurons through EZH2

OBJECTIVE

This study aimed to investigate whether long noncoding RNA sprouty receptor tyrosine kinase signaling antagonist 4-intronic transcript 1 (SPRY4-IT1) is involved in the regulation of ketamine-induced neurotoxicity.

METHODS

Human embryonic stem cells (hESCs) were induced into neurons in vitro and treated with ketamine. Apoptosis and neurite degeneration assays were used to determine ketamine-induced neurotoxicity and qRT-PCR to determine SPRY4-IT1 expression. SPRY4-IT1 was downregulated in hESC-induced neurons to examine its regulation on ketamine-induced neurotoxicity. The correlation between enhancer of zeste homolog 2 (EZH2) and SPRY4-IT1 was also examined. EZH2 was upregulated in SPRY4-IT1-downregualted hESC-induced neurons to further examine its participation in SPRY4-IT1-mediated ketamine neurotoxicity.

RESULTS

Ketamine-induced dose-dependent apoptosis, neurite degeneration, and SPRY4-IT1 upregulation in hESC-induced neurons. Lentivirus-mediated SPRY4-IT1 downregulation protected ketamine neurotoxicity. EZH2 expression was positively correlated with SPRY4-IT1 in hESC-induced neurons. EZH2 overexpression markedly reversed the protective effects of SPRY4-IT1 knockdown on ketamine neurotoxicity.

CONCLUSIONS

SPRY4-IT1 is involved in anesthesia-induced neurotoxicity, possibly through the regulation on EZH2 gene.

A Circular RNA, Cholangiocarcinoma-Associated Circular RNA 1, Contributes to Cholangiocarcinoma Progression, Induces Angiogenesis, and Disrupts Vascular Endothelial Barriers

BACKGROUND AND AIMS

Circular RNAs (circRNAs) and extracellular vesicles (EVs) are involved in various malignancies. We aimed to clarify the functions and mechanisms of dysregulated circRNAs in the cells and EVs of cholangiocarcinoma (CCA).

APPROACH AND RESULTS

CircRNA microarray was used to identify circRNA expression profiles in CCA tissues and bile-derived EVs (BEVs). CCA-associated circRNA 1 (circ-CCAC1) expression was measured by quantitative real-time PCR. The clinical importance of circ-CCAC1 was analyzed by receiver operating characteristic curves, Fisher's exact test, Kaplan-Meier plots, and Cox regression model. The functions of circ-CCAC1 and exosomal circ-CCAC1 were explored in CCA cells and human umbilical vein endothelial cells (HUVECs), respectively. Different animal models were used to verify the in vitro results. RNA sequencing, bioinformatics, RNA immunoprecipitation, RNA pulldown, chromatin immunoprecipitation followed by sequencing, and luciferase reporter assays were used to determine the regulatory networks of circ-CCAC1 in CCA cells and HUVECs. Circ-CCAC1 levels were increased in cancerous bile-resident EVs and tissues. The diagnostic and prognostic values of circ-CCAC1 were identified in patients with CCA. For CCA cells, circ-CCAC1 increased cell progression by sponging miR-514a-5p to up-regulate Yin Yang 1 (YY1). Meanwhile, YY1 directly bound to the promoter of calcium modulating ligand to activate its transcription. Moreover, circ-CCAC1 from CCA-derived EVs was transferred to endothelial monolayer cells, disrupting endothelial barrier integrity and inducing angiogenesis. Mechanistically, circ-CCAC1 increased cell leakiness by sequestering enhancer of zeste homolog 2 in the cytoplasm, thus elevating SH3 domain-containing GRB2-like protein 2 expression to reduce the levels of intercellular junction proteins. In vivo studies further showed that increased circ-CCAC1 levels in circulating EVs and cells accelerated both CCA tumorigenesis and metastasis.

CONCLUSIONS

Circ-CCAC1 plays a vital role in CCA tumorigenesis and metastasis and may be an important biomarker/therapeutic target for CCA.

LSD1 as a Biomarker and the Outcome of Its Inhibitors in the Clinical Trial: The Therapy Opportunity in Tumor

Tumors are the foremost cause of death worldwide. As a result of that, there has been a significant enhancement in the investigation, treatment methods, and good maintenance practices on cancer. However, the sensitivity and specificity of a lot of tumor biomarkers are not adequate. Hence, it is of inordinate significance to ascertain novel biomarkers to forecast the prognosis and therapy targets for tumors. This review characterized LSD1 as a biomarker in different tumors. LSD1 inhibitors in clinical trials were also discussed. The recent pattern advocates that LSD1 is engaged at sauce chromatin zones linking with complexes of multi-protein having an exact DNA-binding transcription factor, establishing LSD1 as a favorable epigenetic target, and also gives a large selection of therapeutic targets to treat different tumors. This review sturdily backing the oncogenic probable of LSD1 in different tumors indicated that LSD1 levels can be used to monitor and identify different tumors and can be a useful biomarker of progression and fair diagnosis in tumor patients. The clinical trials showed that inhibitors of LSD1 have growing evidence of clinical efficacy which is very encouraging and promising. However, for some of the inhibitors such as GSK2879552, though selective, potent, and effective, its disease control was poor as the rate of adverse events (AEs) was high in tumor patients causing clinical trial termination, and continuation could not be supported by the risk-benefit profile. Therefore, we propose that, to attain excellent clinical results of inhibitors of LSD1, much attention is required in designing appropriate dosing regimens, developing in-depth in vitro/in vivo mechanistic works of LSD1 inhibitors, and developing inhibitors of LSD1 that are reversible, safe, potent, and selective which may offer safer profiles.

LINC00514 upregulates CCDC71L to promote cell proliferation, migration and invasion in triple-negative breast cancer by sponging miR-6504-5p and miR-3139

BACKGROUND

Long noncoding RNAs (lncRNAs) have recently identified as essential gene modulators in numerous cancers. Previous studies have confirmed the oncogenic role of long intergenic nonprotein-coding RNA 00514 (LINC00514) in some cancers. Nevertheless, its biological function and mechanism remain unclear in triple-negative breast cancer (TNBC).

METHODS

Herein, we detected LINC00514 expression level in TNBC tissues and cells using RT-qPCR. The function of LINC00514 in TNBC cellular activities was assessed by colony formation, EdU, wound healing, transwell assays and flow cytometry analysis.

RESULTS

The binding between miR-6504-5p/miR-3139 and LINC00514/CCDC71L was validated by luciferase reporter assay. The results indicated that LINC00514 expression was upregulated in TNBC tissues and cells. Furthermore, it was manifested that silenced LINC00514 restrained cell proliferative, migratory and invasive abilities and promoted cell apoptosis. In mechanism, LINC00514 was revealed to sequester miR-6504-5p and miR-3139 in TNBC cells. Furthermore, the low level of miR-6504-5p and miR-3139 was identified in TNBC tissues and cells. Overexpression of miR-6504-5p or miR-3139 inhibited cell growth and migration in TNBC. CCDC71L was recognized as a common downstream gene of miR-6504-5p and miR-3139. Rescue assay verified that overexpressed CCDC71L countervailed the anti-tumor influence of LINC00514 knockdown on TNBC cell proliferation, migration, invasion and apoptosis.

CONCLUSIONS

LINC00514 promote cell proliferation, migration and invasion in triple-negative breast cancer by targeting the miR-6504-5p/miR-3139/CCDC71L axis in TNBC.

Long Non-Coding RNAs: Role in Testicular Cancers

In the last few years lncRNAs have gained increasing attention among the scientific community, thanks to the discovery of their implication in many physio-pathological processes. In particular, their contribution to tumor initiation, progression, and response to treatment has attracted the interest of experts in the oncologic field for their potential clinical application. Testicular cancer is one of the tumors in which lncRNAs role is emerging. Said malignancies already have very effective treatments, which although lead to the development of quite serious treatment-related conditions, such as secondary tumors, infertility, and cardiovascular diseases. It is therefore important to study the impact of lncRNAs in the tumorigenesis of testicular cancer in order to learn how to exploit them in a clinical setting and to substitute more toxic treatments. Eventually, the use of lncRNAs as biomarkers, drug targets, or therapeutics for testicular cancer may represent a valid alternative to that of conventional tools, leading to a better management of this malignancy and its related conditions, and possibly even to the treatment of poor prognosis cases.

Targeting the epigenome in in-stent restenosis: from mechanisms to therapy

Coronary artery disease (CAD) is one of the most common causes of death worldwide. The introduction of percutaneous revascularization has revolutionized the therapy of patients with CAD. Despite the advent of drug-eluting stents, restenosis remains the main challenge in treating patients with CAD. In-stent restenosis (ISR) indicates the reduction in lumen diameter after percutaneous coronary intervention, in which the vessel's lumen re-narrowing is attributed to the aberrant proliferation and migration of vascular smooth muscle cells (VSMCs) and dysregulation of endothelial cells (ECs). Increasing evidence has demonstrated that epigenetics is involved in the occurrence and progression of ISR. In this review, we provide the latest and comprehensive analysis of three separate but related epigenetic mechanisms regulating ISR, namely, DNA methylation, histone modification, and non-coding RNAs. Initially, we discuss the mechanism of restenosis. Furthermore, we discuss the biological mechanism underlying the diverse epigenetic modifications modulating gene expression and functions of VSMCs, as well as ECs in ISR. Finally, we discuss potential therapeutic targets of the small molecule inhibitors of cardiovascular epigenetic factors. A more detailed understanding of epigenetic regulation is essential for elucidating this complex biological process, which will assist in developing and improving ISR therapy.

SOX2 knockdown slows cholangiocarcinoma progression through inhibition of transcriptional activation of lncRNA PVT1

Cholangiocarcinoma (CCA) has accounted for a high rate of mortality and morbidity in the recent years. Long non-coding RNAs (lncRNAs) play an important role in different cellular environments, including cancer. As such, they have been used as potential targets during CCA therapy. The objective of this study was to investigate the effects of lncRNA PVT1 on CCA and its mechanisms behind lncRNA PVT1 regulation. The interactions among SOX2, lncRNA PVT1, miR-186 and SEMA4D were verified by chromatin immunoprecipitation, RNA immunoprecipitation and dual luciferase reporter gene assay. Gain- and loss-of-function experiments were conducted to explore the modulatory effects of SOX2, lncRNA PVT1, miR-186 and SEMA4D on cell viability, migration and invasion of CCA by CCK-8 and Transwell assays. In vivo effects of lncRNA PVT1 or SEMA4D were studied in a nude mouse model. MiR-186 was poorly expressed while SOX2, lncRNA PVT1 and SEMA4D were highly expressed in CCA cells. SOX2 induced the transcriptional activation of lncRNA PVT1 expression to promote proliferation, migration and invasion of CCA cells. LncRNA PVT1 bound to miR-186 and miR-186 was found to target SEMA4D. The overexpression of lncRNA PVT1 and SEMA4D, as well as the inhibition of miR-186 led to elevated CCA cell proliferation, migration and invasion. In vivo experiments confirmed the inhibitory role of lncRNA PVT1 knockdown or SEMA4D knockdown in CCA. All in all, SOX2 down-regulated miR-186 through the transcriptional activation of lncRNA PVT1, whereas elevating SEMA4D expression, thus promoting the progression of CCA.

SP1 induced long non-coding RNA AGAP2-AS1 promotes cholangiocarcinoma proliferation via silencing of CDKN1A

BACKGROUND

LncRNA can regulate gene at various levels such as apparent genetics, alternative splicing, and regulation of mRNA degradation. However, the molecular mechanism of LncRNA in cholangiocarcinoma is still unclear. This deserves further exploration.

METHODS

We investigated the expression of AGAP2-AS1 in 32 CCA tissues and two CCA cell lines. We found a LncRNA AGAP2-AS1 which induced by SP1 has not been reported in CCA, and Knockdown and overexpression were used to investigate the biological role of AGAP2-AS1 in vitro. CHIP and RIP were performed to verify the putative targets of AGAP2-AS1.

RESULTS

AGAP2-AS1 was significantly upregulated in CCA tumor tissues. SP1 induced AGAP2-AS1 plays an important role in tumorigenesis. AGAP2-AS1 knockdown significantly inhibited proliferation and caused apoptosis in CCA cells. In addition, we demonstrated that AGAP2-AS1 promotes the proliferation of CCA.

CONCLUSIONS

We conclude that the long non-coding RNA AGAP2-AS1 plays a role in promoting the proliferation of cholangiocarcinoma.

Elucidation of the Hdac2/Sp1/miR-204-5p/Bcl-2 axis as a modulator of cochlear apoptosis via in vivo/in vitro models of acute hearing loss

We previously reported that dysregulation of histone deacetylase 2 (Hdac2) was associated with the prognosis of sudden sensorineural hearing loss. However, the underlying molecular mechanisms are poorly understood. In the present study, we developed an acute hearing loss animal model in guinea pigs by infusing lipopolysaccharides (LPS) into the cochlea and measured the expression of Hdac2 in the sensory epithelium. We observed that the level of Hdac2 was significantly decreased in the LPS-infused cochleae. The levels of apoptosis-inhibition genes Bcl-2 and Bcl-xl were also decreased in the cochlea and correlated positively with the levels of Hdac2. Caspase3 or TUNEL-positive spiral ganglion neurons, hair cells, and supporting cells were observed in the LPS-infused cochleae. These in vivo observations were recapitulated in cell culture experiments. Based on bioinformatics analysis, we found miR-204-5p was engaged in the regulation of Hdac2 on Bcl-2. Molecular mechanism experiments displayed that miR-204-5p could be regulated by Hdac2 through interacting with transcription factor Sp1. Taken together, these results indicated that the Hdac2/Sp1/miR-204-5p/Bcl-2 regulatory axis mediated apoptosis in the cochlea, providing potential insights into the progression of acute hearing loss. To our knowledge, the study describes a miRNA-related mechanism for Hdac2-mediated regulation in the cochlea for the first time.

Long Non-Coding RNA-PAICC Promotes the Tumorigenesis of Human Intrahepatic Cholangiocarcinoma by Increasing YAP1 Transcription

Intrahepatic cholangiocarcinoma (ICC) is a heterogeneous hepatobiliary tumor with poor prognosis, and it lacks reliable prognostic biomarkers and effective therapeutic targets. Long non-coding RNAs (lncRNAs) have been documented to be involved in the progression of various cancers. However, the role of lncRNAs in ICC remains largely unknown. In the present work, we used bioinformatics analysis to identify the differentially expressed lncRNAs in human ICC tissues, among which lncRNA-PAICC was found to be an independent prognostic marker in ICC. Moreover, lncRNA-PAICC promoted the proliferation and invasion of ICC cells. Mechanistically, lncRNA-PAICC acted as a competitive endogenous RNA (ceRNA) that directly sponged the tumor suppressive microRNAs miR-141-3p and miR-27a-3p. The competitive binding property was essential for lncRNA-PAICC to promote tumor growth and metastasis through activating the Hippo pathway. In summary, our results highlighted the important role of the lncRNA-PAICC-miR-141-3p/27a-3p-Yap1 axis in ICC, which offers a novel perspective on the molecular pathogenesis and may serve as a potential target for antimetastatic molecular therapies of ICC.

DLG1-AS1 is activated by MYC and drives the proliferation and migration of hepatocellular carcinoma cells through miR-497-5p/SSRP1 axis

Background

Long non-coding RNAs (lncRNAs) have been reported to be biological regulators in hepatocellular carcinoma (HCC). DLG1 antisense RNA 1 (DLG1-AS1) has been found to be up-regulated in cervical cancer. However, its function and underlying mechanism in HCC remains unknown.

Methods

DLG1-AS1 expression was assessed in HCC cells and normal cell by RT-qPCR. Luciferase reporter assay, RNA pull down assay and RIP assay were used to demonstrate the interaction between DLG1-AS1 and miR-497-5p.

Results

DLG1-AS1 was highly expressed in HCC cells. Silencing of DLG1-AS1 led to the inhibition of HCC cell growth and migration. Besides, MYC induced the transcriptional activation of DLG1-AS1. MYC could facilitate HCC cellular processes by up-regulating DLG1-AS1. MiR-497-5p could interact with DLG1-AS1 in HCC cells. Down-regulation of miR-497-5p could reverse the impacts of DLG1-AS1 silencing on HCC cells. SSRP1 expression could be positively regulated by DLG1-AS1 but was negatively regulated by miR-497-5p. Knockdown of DLG1-AS1 suppressed tumor growth in nude mice.

Conclusions

DLG1-AS1 is activated by MYC and functions as an oncogene in HCC via miR-497-5p/SSRP1 axis.

STAT1-induced regulation of lncRNA ZFPM2-AS1 predicts poor prognosis and contributes to hepatocellular carcinoma progression via the miR-653/GOLM1 axis

Long noncoding RNAs (lncRNAs) have drawn growing attention owing to their important effects in various tumors, including hepatocellular carcinoma (HCC). Recently, a newly identified lncRNA, ZFPM2 antisense RNA 1 (ZFPM2-AS1), was reported to serve as an oncogene in gastric cancer. However, its function in tumors remains largely unknown. In this study, we identified ZFPM2-AS1 as a novel HCC-related lncRNA, which was observed to be distinctly upregulated in HCC tissues and associated with shorter overall survival. Luciferase reporter and chromatin immunoprecipitation assays suggested that overexpression of ZFPM2-AS1 was induced by STAT1. Functional investigations suggested that the inhibition of ZFPM2-AS1 suppressed cell proliferation, metastasis, cell cycle progression while accelerated cell apoptosis. Mechanistic studies showed that there were two binding sites of miR-653 within the sequence of ZFPM2-AS1 and the levels of ZFPM2-AS1 were negatively correlated with miR-653. In addition, ZFPM2-AS1 could reverse the suppressor effects of miR-653 on the proliferation and metastasis of HCC cells by the modulation of GOLM1, a target gene of miR-653. To conclude, we provided a better understanding of the interaction mechanism between ZFPM2-AS-miR-653-GOLM1 axis, which may help develop prognostic biomarkers and therapeutic target for HCC.

Change on apoptosis, autophagy and mitochondria of the Harderian gland in Cricetulus barabensis during age

Harderian gland (HG) plays an important role in the physiological adaptation to terrestrial life, however, the mechanisms underlying the changes in the structure and function of the HG during aging remain unclear. This study investigated autophagy and apoptosis in the HG of striped dwarf hamsters (Cricetulus barabensis) of different ages (sub-adult, adult and aged groups) in both males and females. The results showed that LC3II/LC3I and puncta of LC3 were significantly higher in adult and aged individuals than sub-adults, whereas P62 decreased with age. Bax/bcl2was the highest in sub-adults of male and female individuals. Caspase3 activity was the highest in sub-adults of male and female individuals, and the citrate synthase activity was highest in sub-adults of females. ATP synthase, citrate synthase, dynamin-related protein 1 and mitochondrial fission factor (Mff) were the highest in sub-adults of females. Peptidylglycine α-amidating monooxygenase were the highest in the aged group, and those of gonadotropin-releasing hormone was the highest in the adult group. LC3II/LC3I, P62, Drp1, Fis, and bax/bcl2 were higher in males than that in females. These results suggest that apoptosis mainly affects growth and development in the HG, whereas autophagy affects aging. The difference of the HG weight and mitochondrial function between sexes is mainly related to the apoptosis.

Novel miRNA Predicts Survival and Prognosis of Cholangiocarcinoma Based on RNA-seq Data and In Vitro Experiments

Accumulating evidence has demonstrated that microRNAs (miRNAs or miRs) play an important role in the diagnosis and prognosis of tumors. In the case of cholangiocarcinoma (CCA), miRNAs may serve as potential tumor biomarkers and therapeutic targets. Based on The Cancer Genome Atlas (TCGA) database, fold change >2 was used to screen out miRNAs with differential expression in patients with CCA. Univariate and multivariate Cox regression analyses identified miR-3913-5p as an independent prognostic factor in patients with CCA. Overall survival and progression-free survival of patients with CCA were analyzed based on clinical data from TCGA database. In addition, four datasets were combined to identify 21 possible target genes of miR-3913, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were conducted to predict potential pathways and functions of the molecular target genes. Subsequently, the miRNAs associated with survival were selected to build the miRNA-mRNA expression network. Furthermore, the differential expression of miR-3913-5p in CCA cells and normal bile duct epithelial cells was confirmed through in vitro experiments. The possible target genes (RNF24 and SIGLEC) were further screened by reverse transcription-quantitative PCR. In addition, functional experiments showed that miR-3913-5p might be an oncogene that affects the proliferation and migration of CCA cells by inhibiting and mimicking miR-3913-5p. Therefore, miR-3913 may serve as a biomarker for the diagnosis and prognosis of patients with CCA.

A novel circular RNA circ-LRIG3 facilitates the malignant progression of hepatocellular carcinoma by modulating the EZH2/STAT3 signaling

BACKGROUND

Circular RNA (circRNA) is emerging as an important player in human diseases, especially cancer. In our previous study, we identified a series of deregulated circRNAs in hepatocellular carcinoma (HCC) by performing circRNA microarray expression profile. Here, we aimed to explore the role of circ-LRIG3 (hsa_circ_0027345) in HCC.

METHODS

qRT-PCR and western blot were used to asses gene and protein expression, respectively. CCK-8, EdU and Transwell assays were used to detect cell proliferation, migration and invasion. GSEA software was applied to analyze the pathway related to circ-LRIG3. Co-IP, RIP and ChIP assays were used to identify the positive feedback axis of circ-LRIG3/EZH2/STAT3. Animal study was carried to test the role of circ-LRIG3 in vivo.

RESULTS

Circ-LRIG3 was notably upregulated in HCC and promoted HCC cell proliferation, migration, invasion and reduced apoptosis. Circ-LRIG3 formed a ternary complex with EZH2 and STAT3, facilitating EZH2-induced STAT3 methylation and subsequent phosphorylation, resulting in the activation of STAT3 signaling. In turn, activated STAT3 could directly bind to circ-LRIG3 promoter to increase circ-LRIG3 transcription activity, thus forming a positive feedback loop. The animal models showed that exogenous expression of circ-LRIG3 enhanced tumorigenicity and metastasis in vivo, whereas these effects were blocked after treatment with C188-9, a specific STAT3 small-molecule inhibitor. Clinically, high circ-LRIG3 was closely linked with aggressive clinicopathological features and was identified as an independent risk prognostic factor of overall survival. Importantly, plasma circ-LRIG3 was found to be a highly sensitive and specific non-invasive diagnostic indicator for HCC.

CONCLUSIONS

Our study reveals the carcinogenic role of circ-LRIG3 in HCC, which may provide a new therapeutic target for HCC patients.

Emerging roles of long noncoding RNAs in cholangiocarcinoma: Advances and challenges

Cholangiocarcinoma (CCA), a cancer with a relatively low incidence rate, is usually associated with poor prognosis. Current modalities for the diagnosis and treatment of CCA patients are still far from satisfactory. In recent years, numerous long noncoding RNAs (lncRNAs) have been identified as crucial players in the development of various cancers, including CCA. Abnormally expressed lncRNAs in CCA, regulated by some upstream molecules, significantly influence the biological behavior of tumor cells and are involved in tumor development through various mechanisms, including interactions with functional proteins, participation in competing for endogenous RNA (ceRNA) regulatory networks, activation of cancer‐related signaling pathways and epigenetic modification of gene expression. Furthermore, several lncRNAs are closely associated with the clinicopathological features of CCA patients, and are promising biomarkers for diagnosing and prognostication of CCA. Some of these lncRNAs play an important role in chemotherapy drug resistance. In addition, lncRNAs have also been shown to be involved in the inflammation microenvironment of CCA and malignant outcome of CCA risk factors, such as cholestatic liver diseases. In view of the difficulty of diagnosing CCA, more attention should be paid to detectable lncRNAs in the serum or bile. This review summarizes the recent knowledge on lncRNAs in CCA and provides a new outlook on the molecular mechanisms of CCA development from the perspective of lncRNAs. Moreover, we also discussed the limitations of the current studies and differential expression of lncRNAs in different types of CCA.