Long noncoding RNA MEG3 regulates LATS2 by promoting the ubiquitination of EZH2 and inhibits proliferation and invasion in gallbladder cancer

Upregulation of OGT-mediated EZH2 O-GlcNAcylation Promotes Human Umbilical Vein Endothelial Cell Proliferation, Invasion, Migration, and Tube Formation in Gestational Diabetes Mellitus

O-linked N-acetylglucosamine transferase (OGT)-catalyzed O-linked N-acetylglucosamine glycosylation (O-GlcNAcylation) is closely associated with diabetes progression. This study aims to investigate the mechanism of OGT in regulating endothelial dysfunction in gestational diabetes mellitus (GDM). Expressions of OGT, O-linked N-acetylglucosamine (O-GlcNAc), enhancer of zeste homolog 2 (EZH2), and HEK27me3 in human umbilical vein endothelial cells (HUVECs) and GDM-derived HUVECs (GDM-HUVECs) were assessed by western blot. RT-qPCR and western blot assays were used to test the OGT overexpression and EZH2 silencing levels. CCK-8, EdU, wound healing, and transwell invasion assays were used to analyze the cell proliferative, migratory, and invasive abilities. Tube formation assay was performed to evaluate angiogenesis ability of cells. Western blot assay was performed to estimate vascular endothelial growth factor (VEGF) and p-VEGFR2 levels in cells. The binding of O-GlcNAc and EZH2 after OGT overexpression was measured by Co-IP assay. The results showed that OGT, O-GlcNAc, EZH2, and HEK27me3 expressions were declined in GDM-HUVECs. OGT overexpression induced the proliferation, migration, and invasion of GDM-HUVECs, and also elevated angiogenesis and the expressions of VEGF and p-VEGFR2 in cells. O-GlcNAc, EZH2, and HEK27me3 expressions were upregulated after OGT overexpression. OGT upregulation induced the binding between O-GlcNAc and EZH2. EZH2 silencing attenuated the promotion of OGT overexpression on the proliferative, invasive, migratory, and angiogenic capacities of GDM-HUVECs. To be concluded, OGT overexpression stabilized EZH2 expression by promoting O-GlcNAcylation modification of EZH2, and further enhanced proliferation, migration, and invasion as well as angiogenesis of GDM-HUVECs. While these effects were decayed after EZH2 absenting. Overall, the modulation of OGT on endothelial dysfunction in GDM provides a novel perspective for the clinical treatment of GDM.

Natural products and long noncoding RNA signatures in gallbladder cancer: a review focuses on pathogenesis, diagnosis, and drug resistance

Gallbladder cancer (GBC) is an aggressive and lethal malignancy with a poor prognosis. Long noncoding RNAs (lncRNAs) and natural products have emerged as key orchestrators of cancer pathogenesis through widespread dysregulation across GBC transcriptomes. Functional studies have revealed that lncRNAs interact with oncoproteins and tumor suppressors to control proliferation, invasion, metastasis, angiogenesis, stemness, and drug resistance. Curcumin, baicalein, oleanolic acid, shikonin, oxymatrine, arctigenin, liensinine, fangchinoline, and dioscin are a few examples of natural compounds that have demonstrated promising anticancer activities against GBC through the regulation of important signaling pathways. The lncRNAs, i.e., SNHG6, Linc00261, GALM, OIP5-AS1, FOXD2-AS1, MINCR, DGCR5, MEG3, GATA6-AS, TUG1, and DILC, are key players in regulating the aforementioned processes. For example, the lncRNAs FOXD2-AS1, DILC, and HOTAIR activate oncogenes such as DNMT1, Wnt/β-catenin, BMI1, and c-Myc, whereas MEG3 and GATA6-AS suppress the tumor proteins NF-κB, EZH2, and miR-421. Clinically, specific lncRNAs can serve as diagnostic or prognostic biomarkers based on overexpression correlating with advanced TNM stage, metastasis, chemoresistance, and poor survival. Therapeutically, targeting aberrant lncRNAs with siRNA or antisense oligos disrupts their oncogenic signaling and inhibits GBC progression. Overall, dysfunctional lncRNA regulatory circuits offer multiple avenues for precision medicine approaches to improve early GBC detection and overcome this deadly cancer. They have the potential to serve as novel biomarkers as they are detectable in bodily fluids and tissues. These findings enhance gallbladder treatments, mitigating resistance to chemo- and radiotherapy.

Glioblastoma stem cell long non-coding RNAs: therapeutic perspectives and opportunities

Glioblastoma poses a formidable challenge among primary brain tumors: its tumorigenic stem cells, capable of self-renewal, proliferation, and differentiation, contribute substantially to tumor initiation and therapy resistance. These glioblastoma stem cells (GSCs), resembling conventional stem and progenitor cells, adopt pathways critical for tissue development and repair, promoting uninterrupted tumor expansion. Long non-coding RNAs (lncRNAs), a substantial component of the human transcriptome, have garnered considerable interest for their pivotal roles in normal physiological processes and cancer pathogenesis. They display cell- or tissue-specific expression patterns, and extensive investigations have highlighted their impact on regulating GSC properties and cellular differentiation, thus offering promising avenues for therapeutic interventions. Consequently, lncRNAs, with their ability to exert regulatory control over tumor initiation and progression, have emerged as promising targets for innovative glioblastoma therapies. This review explores notable examples of GSC-associated lncRNAs and elucidates their functional roles in driving glioblastoma progression. Additionally, we delved deeper into utilizing a 3D in vitro model for investigating GSC biology and elucidated four primary methodologies for targeting lncRNAs as potential therapeutics in managing glioblastoma.

Celastrol Ameliorates Neuronal Mitochondrial Dysfunction Induced by Intracerebral Hemorrhage via Targeting cAMP-Activated Exchange Protein-1

Mitochondrial dysfunction contributes to the development of secondary brain injury (SBI) following intracerebral hemorrhage (ICH) and represents a promising therapeutic target. Celastrol, the primary active component of Tripterygium wilfordii, is a natural product that exhibits mitochondrial and neuronal protection in various cell types. This study aims to investigate the neuroprotective effects of celastrol against ICH-induced SBI and explore its underlying mechanisms. Celastrol improves neurobehavioral and cognitive abilities in mice with autologous blood-induced ICH, reduces neuronal death in vivo and in vitro, and promotes mitochondrial function recovery in neurons. Single-cell nuclear sequencing reveals that the cyclic adenosine monophosphate (cAMP)/cAMP-activated exchange protein-1 (EPAC-1) signaling pathways are impacted by celastrol. Celastrol binds to cNMP (a domain of EPAC-1) to inhibit its interaction with voltage-dependent anion-selective channel protein 1 (VDAC1) and blocks the opening of mitochondrial permeability transition pores. After neuron-specific knockout of EPAC1, the neuroprotective effects of celastrol are diminished. In summary, this study demonstrates that celastrol, through its interaction with EPAC-1, ameliorates mitochondrial dysfunction in neurons, thus potentially improving SBI induced by ICH. These findings suggest that targeting EPAC-1 with celastrol can be a promising therapeutic approach for treating ICH-induced SBI.

Harnessing the supremacy of MEG3 LncRNA to defeat gastrointestinal malignancies

Evidence suggests that long non-coding RNAs (lncRNAs) play a pivotal role in the carcinogenesis and progression of various human malignancies including gastrointestinal malignancies. This comprehensive review reports the functions and mechanisms of the lncRNA maternally expressed gene 3 (MEG3) involved in gastrointestinal malignancies. It summarizes its roles in mediating the regulation of cellular proliferation, apoptosis, migration, invasiveness, epithelial-to-mesenchymal transition, and drug resistance in several gastrointestinal cancers such as colorectal cancer, gall bladder cancer, pancreatic cancer, gastric cancer, esophageal cancer, cholangiocarcinoma, gastrointestinal stromal tumors and most importantly, hepatocellular carcinoma. In addition, the authors briefly highlight its implicated mechanistic role and interactions with different non-coding RNAs and oncogenic signaling cascades. This review presents the rationale for developing non coding RNA-based anticancer therapy via harnessing the power of MEG3 in gastrointestinal malignancies.

Decoding the role of long non-coding RNAs in gallbladder cancer pathogenesis: A review focus on signaling pathways interplay

Gallbladder cancer (GBC) is one of the most aggressive types of biliary tree cancers and the commonest despite its rarity. It is infrequently diagnosed at an early stage, further contributing to its poor prognosis and low survival rate. The lethal nature of the disease has underlined a crucial need to discern the underlying mechanisms of GBC carcinogenesis which are still largely unknown. However, with the continual evolution in the research of cancer biology and molecular genetics, studies have found that non-coding RNAs (ncRNAs) play an active role in the molecular pathophysiology of GBC development. Dysregulated long non-coding RNAs (lncRNAs) and their interaction with intracellular signaling pathways contribute to malignancy and disease development. LncRNAs, a subclass of ncRNAs with over 200 nucleotides, regulate gene expression at transcriptional, translational, and post-translational levels and especially as epigenetic modulators. Thus, their expression abnormalities have been linked to malignancy and therapeutic resistance. lnsRNAs have also been found in GBC patients' serum and tumor tissue biopsies, highlighting their potential as novel biomarkers and for targeted therapy. This review will examine the growing involvement of lncRNAs in GBC pathophysiology, including related signaling pathways and their wider clinical use.

MicroRNA let-7c-5p Alleviates in Hepatocellular Carcinoma by Targeting Enhancer of Zeste Homolog 2: A Study Intersecting Bioinformatic Analysis and Validated Experiments

Enhancer of zeste homolog 2 (EZH2)gene has a prognostic role in hepatocellular carcinoma (HCC). This study aimed to identify the role of microRNAs (miRNAs) let-7c-5p by targeting EZH2 in HCC. We downloaded gene and miRNA RNA-seq data from The Cancer Genome Atlas (TCGA) database. Differences in EZH2 expression between different groups were analyzed and the association of EZH2 expression with HCC prognosis was detected using Cox regression analysis. The miRNA-EZH2-pathway network was constructed. Dual-luciferase reporter assay was performed to detect the hsa-let-7c-5p-EZH2. Cell proliferation, migration, invasion, and apoptosis were detected by CCK-8, Wound healing, Transwell, and Flow cytometry, respectively. RT-qPCR and Western blot were used to detect the expression of let-7c-5p and EZH2. EZH2 was upregulated in HCC tumors (P < 0.0001). Cox regression analysis showed that TCGA HCC patients with high EZH2 expression levels showed a short survival time [hazard ratio (HR) = 1.677, 95% confidence interval (CI) 1.316-2.137; P < 0.0001]. Seven miRNAs were negatively correlated with EZH2 expression and were significantly downregulated in HCC tumor samples (P < 0.0001), in which hsa-let-7c-5p was associated with prognosis in HCC (HR = 0.849 95% CI 0.739-0.975; P = 0.021). We identified 14 immune cells that showed significant differences in EZH2 high- and low-expression groups. Additionally, let-7c-5p inhibited HCC cell proliferation, migration, and invasion and reversed the promoted effects of EZH2 on HCC cell malignant characteristics. hsa-let-7c-5p-EZH2 significantly suppressed HCC malignant characteristics, which can be used for HCC prognosis.

EZH2 Promotes Corneal Endothelial Cell Apoptosis by Mediating H3K27me3 and Inhibiting HO-1 Transcription

PURPOSE

This paper aims to explore the molecular mechanism of Enhancer of Zeste Homolog 2 (EZH2)-mediated H3K27me3 in human corneal endothelial cells (HCEC) apoptosis by inhibiting Heme oxygenase-1 (HO-1) transcription to provide a potential target for the treatment of corneal apoptosis.

METHODS

HCECs were cultured in vitro and transfected with si-EZH2, pcDNA3.1-EZH2, pcDNA3.1-HO-1, GSK-J4 (an effective H3K27me3 demethylase inhibitor), and corresponding controls. Western Blot assay was used to detect the levels of EZH2, HO-1, H3K27me3, and apoptosis-related proteins (Bcl-2, Bax, and Cleaved-caspase-3) in HCECs; CCK-8 assay was conducted to detect cell viability and flow cytometry to analyze the apoptosis. HO-1 mRNA levels were detected by RT-qPCR and changes in H3K27me3 levels on the HO-1 promoter were detected by chromatin immunoprecipitation.

RESULTS

HCECs transfected with si-EZH2 showed significantly lower EZH2 mRNA and protein levels, higher HCEC viability, lower apoptosis rates, higher antiapoptotic protein Bcl-2 expression, lower proapoptotic protein (Bax and Cleaved-caspase-3) levels, and significantly higher HO-1 expression. HCECs transfected with pcDNA3.1-EZH2 showed the opposite results. EZH2 repressed HO-1 transcription by mediating H3K27me3. H3K27me27 was enriched in the HO-1 promoter and overexpression of EZH2 increased H3K27me27 levels. Promotion of H3K27me3 partially reversed the mitigating effect of si-EZH2 on HCEC apoptosis. Overexpression of HO-1 partially reversed the apoptosis-promoting effects of EZH2 and H3K27me3 on HCECs.

CONCLUSIONS

EZH2 promotes HCE cell apoptosis by mediating H3K27me3 to inhibit HO-1 transcription.

HNRNPA2B1-mediated m6A modification of lncRNA MEG3 facilitates tumorigenesis and metastasis of non-small cell lung cancer by regulating miR-21-5p/PTEN axis

BACKGROUND

Accumulating data indicate that N6-methyladenosine (m⁶A) RNA methylation and lncRNA deregulation act crucial roles in cancer progression. Heterogeneous nuclear ribonucleoprotein A2B1 (HNRNPA2B1) as an m⁶A "reader" has been reported to be an oncogene in multiple malignancies. We herein aimed to elucidate the role and underlying mechanism by which HNRNPA2B1-mediated m⁶A modification of lncRNAs contributes to non-small cell lung cancer (NSCLC).

METHODS

The expression levels of HNRNPA2B1 and their association with the clinicopathological characteristics and prognosis in NSCLC were determined by RT-qPCR, Western blot, immunohistochemistry and TCGA dataset. Then, the role of HNRNPA2B1 in NSCLC cells was assessed by in vitro functional experiments and in vivo tumorigenesis and lung metastasis models. HNRNPA2B1-mediated m⁶A modification of lncRNAs was screened by m⁶A-lncRNA epi-transcriptomic microarray and verified by methylated RNA immunoprecipitation (Me-RIP). The lncRNA MEG3-specific binding with miR-21-5p was evaluated by luciferase gene report and RIP assays. The effects of HNRNPA2B1 and (or) lncRNA MEG3 on miR-21-5p/PTEN/PI3K/AKT signaling were examined by RT-qPCR and Western blot analyses.

RESULTS

We found that upregulation of HNRNPA2B1 was associated with distant metastasis and poor survival, representing an independent prognostic factor in patients with NSCLC. Knockdown of HNRNPA2B1 impaired cell proliferation and metastasis in vitro and in vivo, whereas ectopic expression of HNRNPA2B1 possessed the opposite effects. Mechanical investigations revealed that lncRNA MEG3 was an m⁶A target of HNRNPA2B1 and inhibition of HNRNPA2B1 decreased MEG3 m⁶A levels but increased its mRNA levels. Furthermore, lncRNA MEG3 could act as a sponge of miR-21-5p to upregulate PTEN and inactivate PI3K/AKT signaling, leading to the suppression of cell proliferation and invasion. Low expression of lncRNA MEG3 or elevated expression of miR-21-5p indicated poor survival in patients with NSCLC.

CONCLUSIONS

Our findings uncover that HNRNPA2B1-mediated m⁶A modification of lncRNA MEG3 promotes tumorigenesis and metastasis of NSCLC cells by regulating miR-21-5p/PTEN axis and may provide a therapeutic target for NSCLC.

The Biological Roles and Molecular Mechanisms of Long Non-Coding RNA MEG3 in the Hallmarks of Cancer

Long non-coding RNAs (lncRNAs) are critical regulators in various biological processes involved in the hallmarks of cancer. Maternally expressed gene 3 (MEG3) is lncRNA that regulates target genes through transcription, translation, post-translational modification, and epigenetic regulation. MEG3 has been known as a tumor suppressor, and its downregulation could be found in various cancers. Furthermore, clinical studies revealed that impaired MEG3 expression is associated with poor prognosis and drug resistance. MEG3 exerts its tumor suppressive effect by suppressing various cancer hallmarks and preventing cells from acquiring cancer-specific characteristics; as it could suppress tumor cells proliferation, invasion, metastasis, and angiogenesis; it also could promote tumor cell death and regulate tumor cell metabolic reprogramming. Hence, MEG3 is a potential prognostic marker, and overexpressing MEG3 might become a potential antitumor therapeutic strategy. Herein, we summarize recent knowledge regarding the role of MEG3 in regulating tumor hallmarks as well as the underlying molecular mechanisms. Furthermore, we also discuss the clinical importance of MEG3, as well as their potential in tumor prognosis and antitumor therapeutic strategies.

A review of current evidence about lncRNA MEG3: A tumor suppressor in multiple cancers

Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3) is a lncRNA located at the DLK1-MEG3 site of human chromosome 14q32.3. The expression of MEG3 in various tumors is substantially lower than that in normal adjacent tissues, and deletion of MEG3 expression is involved in the occurrence of many tumors. The high expression of MEG3 could inhibit the occurrence and development of tumors through several mechanisms, which has become a research hotspot in recent years. As a member of tumor suppressor lncRNAs, MEG3 is expected to be a new target for tumor diagnosis and treatment. This review discusses the molecular mechanisms of MEG3 in different tumors and future challenges for the diagnosis and treatment of cancers through MEG3.

Sam50 exerts neuroprotection by maintaining the mitochondrial structure during experimental cerebral ischemia/reperfusion injury in rats

AIM

To investigate the role of Sam50, a barrel protein on the surface of the mitochondrial outer membrane, in cerebral ischemia-reperfusion (I/R) injury and its underlying mechanisms.

METHODS

A middle cerebral artery occlusion/reperfusion (MCAO/R) model in adult male Sprague-Dawley rats was established in vivo, and cultured neurons were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to simulate I/R injury in vitro. Lentiviral vector encoding Sam50 or Sam50 shRNA was constructed and administered to rats by intracerebroventricular injection to overexpress and knockdown Sam50, respectively.

RESULTS

First, after MCAO/R induction, the mitochondrial structure was damaged, and Sam50 protein levels were increased responsively both in vivo and in vitro. Then, it was found that Sam50 overexpression could reduce infarction size, inhibit neuronal cell death, improve neurobehavioral disability, protect mitochondrial structure integrity, and ameliorate mitochondrial dysfunction, which was induced by I/R injury both in vivo and in vitro. However, Sam50 downregulation showed the opposite results and aggravated I/R injury by inducing neuronal cell death, neurobehavioral disability, and mitochondrial dysfunction. Moreover, we found that the interaction between Sam50 and Mic19 was broken off after OGD/R, showing that the Sam50-Mic19-Mic60 axis was breakage in neurons, which would be a reason for mitochondrial structure and function abnormalities induced by I/R injury.

CONCLUSION

Sam50 played a vital role in the protection of neurons and mitochondria in cerebral I/R injury, which could be a novel target for mitochondrial protection and ameliorating I/R injury.

Noncoding RNAs in liver physiology and metabolic diseases

The liver holds central roles in detoxification, energy metabolism and whole-body homeostasis but can develop malignant phenotypes when being chronically overwhelmed with fatty acids and glucose. The global rise of metabolic-associated fatty liver disease (MAFLD) is already affecting a quarter of the global population. Pharmaceutical treatment options against different stages of MAFLD do not yet exist and several clinical trials against hepatic transcription factors and other proteins have failed. However, emerging roles of noncoding RNAs, including long (lncRNA) and short noncoding RNAs (sRNA), in various cellular processes pose exciting new avenues for treatment interventions. Actions of noncoding RNAs mostly rely on interactions with proteins, whereby the noncoding RNA fine-tunes protein function in a process termed riboregulation. The developmental stage-, disease stage- and cell type-specific nature of noncoding RNAs harbors enormous potential to precisely target certain cellular pathways in a spatio-temporally defined manner. Proteins interacting with RNAs can be categorized into canonical or non-canonical RNA binding proteins (RBPs) depending on the existence of classical RNA binding domains. Both, RNA- and RBP-centric methods have generated new knowledge of the RNA-RBP interface and added an additional regulatory layer. In this review, we summarize recent advances of how of RBP-lncRNA interactions and various sRNAs shape cellular physiology and the development of liver diseases such as MAFLD and hepatocellular carcinoma.

Noncoding RNAs in Thyroid-Follicular-Cell-Derived Carcinomas

Simple Summary

Thyroid tumors represent the most common neoplastic pathology of the endocrine system. Mutations occurring in oncogenes and tumor suppressor genes are responsible for thyroid carcinogenesis; however, the complete mutational landscape characterizing these neoplasias has not been completely unveiled. It has been established that only the 2% of the human genome codes for proteins, suggesting that the vast majority of the genome has regulatory capabilities, which, if altered, could account for the onset of cancer. Hence, many scientific efforts are currently focused on the characterization of the heterogeneous class of noncoding RNAs, which represent an abundant part of the transcribed noncoding genome. In this review, we mainly focus on the involvement of microRNAs, long noncoding RNAs, and pseudogenes in thyroid cancer. The determination of the diagnosis, prognosis, and treatment of thyroid cancers based on the evaluation of the noncoding RNA network could allow the implementation of a more personalized approach to fighting these pathologies.

Abstract

Among the thyroid neoplasias originating from follicular cells, we can include well-differentiated carcinomas, papillary (PTC) and follicular (FTC) thyroid carcinomas, and the undifferentiated anaplastic (ATC) carcinomas. Several mutations in oncogenes and tumor suppressor genes have already been observed in these malignancies; however, we are still far from the comprehension of their full regulation-altered landscape. Even if only 2% of the human genome has the ability to code for proteins, most of the noncoding genome is transcribed, constituting the heterogeneous class of noncoding RNAs (ncRNAs), whose alterations are associated with the development of several human diseases, including cancer. Hence, many scientific efforts are currently focused on the elucidation of their biological role. In this review, we analyze the scientific literature regarding the involvement of microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and pseudogenes in FTC, PTC, and ATC. Recent findings emphasized the role of lncRNAs in all steps of cancer progression. In particular, lncRNAs may control progression steps by regulating the expression of genes and miRNAs involved in cell proliferation, apoptosis, epithelial–mesenchymal transition, and metastatization. In conclusion, the determination of the diagnosis, prognosis, and treatment of cancer based on the evaluation of the ncRNA network could allow the implementation of a more personalized approach to fighting thyroid tumors.

SNP rs322931 (C>T) in miR-181b and rs7158663 (G>A) in MEG3 aggravate the inflammatory response of anal abscess in patients with Crohn's disease

BACKGROUND

The MEG3/miR-181b signaling has been implicated in the pathogenesis of several diseases including Crohn's disease. This work aimed to study the correlation between SNPs in MEG3/miR-181b and the severity of anal abscess in patients with Crohn's disease.

METHODS

Quantitative real-time PCR was performed to analyze the expression of MEG3 and miR-181b. ELISA was carried out to examine the expression of TNF-α, IL-1β, IL-6, CRP, SSA, AAT, AAG and HPT in the peripheral blood of patients with Crohn's disease. Luciferase assay was performed to explore the role of miR-181b in the expression of MEG3 and TNF-α.

RESULTS

The expression of MEG3 and miR-181b in the peripheral blood of patients with Crohn's disease was remarkably associated with the rs322931 and rs7158663 polymorphisms. rs322931 (C>T) in miR-181b and rs7158663 (G>A) in MEG3 significantly promoted the expression of TNF-α, IL-1β, IL-6, CRP, SSA, AAT, AAG and HPT. Luciferase assay demonstrated that miR-181b was capable of repressing the expression of MEG3 and TNF-α through binding to their specific binding sites. Moreover, alteration of MEG3 and miR-181b expression also showed a remarkable impact on the MEG3/miR-181b/TNF-α signaling pathway in THP-1 cells.

CONCLUSIONS

In conclusion, our study demonstrated that two SNPs, rs322931 (C>T) in miR-181b and rs7158663 (G>A) in MEG3, could aggravate the inflammatory response of anal abscess in patients with Crohn's disease via modulating the MEG3/miR-181b/TNF-α signaling pathway.

LncRNA MEG3 up-regulates SIRT6 by ubiquitinating EZH2 and alleviates nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a global health threat. Here, we presented the significant role of a novel signaling axis comprising long non-coding RNA maternally expressed gene 3 (MEG3), enhancer of zeste homolog 2 (EZH2), and sirtuin 6 (SIRT6) in controlling lipid accumulation, inflammation, and the progression of NAFLD. Mice fed with high-fat diet (HFD) were established as in vitro and in vivo NAFLD models, respectively. Lipid accumulation was measured by oil red O staining and assays for triglycerides or cholesterol. Inflammation was examined by ELISA for pro-inflammatory cytokines. Gene expressions were examined by RT-qPCR or Western blot. Interactions between key signaling molecules were examined by combining expressional analysis, RNA immunoprecipitation, cycloheximide stability assay, co-immunoprecipitation, and chromatin immunoprecipitation. MEG3 level was reduced in FFA-challenged hepatocytes or liver from HFD-fed mice, and the reduction paralleled the severity of NAFLD in clinic. Overexpressing MEG3 suppressed FFA-induced lipid accumulation or inflammation in hepatocytes. By promoting the ubiquitination and degradation of EZH2, MEG3 upregulated SIRT6, an EZH2 target. SIRT6 essentially mediated the protective effects of MEG3 in hepatocytes. Consistently, overexpressing MEG3 alleviated HFD-induced NAFLD in vivo. By controlling the expressions of genes involved in lipid metabolism and inflammation, the MEG3/EZH2/SIRT6 axis significantly suppressed lipid accumulation and inflammation in vitro, and NAFLD development in vivo. Therefore, boosting MEG3 level may benefit the treatment of NAFLD.

Engineered exosome as targeted lncRNA MEG3 delivery vehicles for osteosarcoma therapy

Exosomes as nanosized membrane vesicles, could targeted deliver therapeutic agents by modification with target ligands. Exosome-derived non-coding RNAs play a vital role in the development of tumors. Previous evidences reveal that long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) has anti-tumor properties. Whereas, the inhibitory effects of exosome-derived lncRNA MEG3 in osteosarcoma (OS) remain largely unknown. In this study, we utilize the engineering technology to combine exosome and lncRNA for tumor-targeting therapy of OS. We elucidated the anti-OS effects of lncRNA MEG3, and then prepared the c(RGDyK)-modified and MEG3-loaded exosomes (cRGD-Exo-MEG3). The engineered exosomes cRGD-Exo-MEG3 could deliver more efficiently to OS cells both in vitro and in vivo. In this way, cRGD-Exo-MEG3 facilitate the anti-OS effects of MEG3 significantly, with the help of enhanced tumor-targeting therapy. This study elucidates that engineered exosomes as targeted lncRNA MEG3 delivery vehicles have potentially therapeutic effects for OS.

Molecular Mechanisms of lncRNAs in the Dependent Regulation of Cancer and Their Potential Therapeutic Use

Deep whole genome and transcriptome sequencing have highlighted the importance of an emerging class of non-coding RNA longer than 200 nucleotides (i.e., long non-coding RNAs (lncRNAs)) that are involved in multiple cellular processes such as cell differentiation, embryonic development, and tissue homeostasis. Cancer is a prime example derived from a loss of homeostasis, primarily caused by genetic alterations both in the genomic and epigenetic landscape, which results in deregulation of the gene networks. Deregulation of the expression of many lncRNAs in samples, tissues or patients has been pointed out as a molecular regulator in carcinogenesis, with them acting as oncogenes or tumor suppressor genes. Herein, we summarize the distinct molecular regulatory mechanisms described in literature in which lncRNAs modulate carcinogenesis, emphasizing epigenetic and genetic alterations in particular. Furthermore, we also reviewed the current strategies used to block lncRNA oncogenic functions and their usefulness as potential therapeutic targets in several carcinomas.

Meta-analysis of transcriptomics data identifies potential biomarkers and their associated regulatory networks in gallbladder cancer

Aim

This study aimed to identify key genes, non-coding RNAs, and their possible regulatory interactions during gallbladder cancer (GBC).

Background

The early detection of GBC, i.e. before metastasis, is restricted by our limited knowledge of molecular markers and mechanism(s) involved during carcinogenesis. Therefore, identifying important disease-associated transcriptome-level alterations can be of clinical importance.

Methods

In this study, six NCBI-GEO microarray dataseries of GBC and control tissue samples were analyzed to identify differentially expressed genes (DEGs) and non-coding RNAs {microRNAs (DEmiRNAs) and long non-coding RNAs (DElncRNAs)} with a computational meta-analysis approach. A series of bioinformatic methods were applied to enrich functional pathways, create protein-protein interaction networks, identify hub genes, and screen potential targets of DEmiRNAs and DElncRNAs. Expression and interaction data were consolidated to reveal putative DElncRNAs:DEmiRNAs:DEGs interactions.

Results

In total, 351 DEGs (185 downregulated, 166 upregulated), 787 DEmiRNAs (299 downregulated, 488 upregulated), and 7436 DElncRNAs (3127 downregulated, 4309 upregulated) were identified. Eight genes (FGF, CDK1, RPN2, SEC61A1, SOX2, CALR, NGFR, and NCAM) were identified as hub genes. Genes associated with ubiquitin ligase activity, N-linked glycosylation, and blood coagulation were upregulated, while those for cell-cell adhesion, cell differentiation, and surface receptor-linked signaling were downregulated. DEGs-DEmiRNAs-DElncRNAs interaction network identified 46 DElncRNAs to be associated with 28 DEmiRNAs, consecutively regulating 27 DEGs. DEmiRNAs-hsa-miR-26b-5p and hsa-miR-335-5p; and DElnRNAs-LINC00657 and CTB-89H12.4 regulated the highest number of DEGs and DEmiRNAs, respectively.

Conclusion

The current study has identified meaningful transcriptome-level changes and gene-miRNA-lncRNA interactions during GBC and laid a platform for future studies on novel prognostic and diagnostic markers in GBC.

Reiterating the Emergence of Noncoding RNAs as Regulators of the Critical Hallmarks of Gall Bladder Cancer

Gall bladder cancer (GBC) is a rare and one of the most aggressive types of malignancies, often associated with a poor prognosis and survival. It is a highly metastatic cancer and is often not diagnosed at the initial stages, which contributes to a poor survival rate of patients. The poor diagnosis and chemoresistance associated with the disease limit the scope of the currently available surgical and nonsurgical treatment modalities. Thus, there is a need to explore novel therapeutic targets and biomarkers that will help relieve the severity of the disease and lead to advanced therapeutic strategies. Accumulating evidence has correlated the atypical expression of various noncoding RNAs (ncRNAs), including circular RNAs (circRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and small nucleolar RNAs (snoRNA) with the increased cell proliferation, epithelial-mesenchymal transition (EMT), invasion, migration, metastasis, chemoresistance, and decreased apoptosis in GBC. Numerous reports have indicated that the dysregulated expression of ncRNAs is associated with poor prognosis and lower disease-free and overall survival in GBC patients. These reports suggest that ncRNAs might be considered novel diagnostic and prognostic markers for the management of GBC. The present review recapitulates the association of various ncRNAs in the initiation and progression of GBC and the development of novel therapeutic strategies by exploring their functional and regulatory role.

CircTP63 promotes cell proliferation and invasion by regulating EZH2 via sponging miR-217 in gallbladder cancer

Background

Gallbladder cancer (GBC) is the most common biliary tract malignancy and has a poor prognosis in patients with GBC. CircRNA TP63 (circTP63) has been implicated in cell proliferation and invasion in some tumor progress. The study aims to investigate the clinical significance and functional role of circTP63 expression in GBC.

Methods

The expression of circTP63 in GBC tissues or cells was detected by qRT-PCR and the association between circTP63 expression and prognosis of GBC patients was analyzed. CCK8 assay, flow cytometry analysis, transwell assay and in vivo studies were used to evaluate the cell proliferation and invasion abilities after circTP63 knockdown in GBC cells. Luciferase reporter assays and RNA pull-down assay were used to determine the correlation between circTP63 and miR-217 expression. Besides, western blot analysis was also performed.

Results

In the present study, we showed that circTP63 expression was upregulated in GBC tissues and cells. Higher circTP63 expression was associated with lymph node metastasis and short overall survival (OS) in patients with GBC. In vitro, knockdown of circTP63 significantly inhibited cell proliferation, cell cycle progression, migration and invasion abilities in GBC. Besides, we demonstrated that knockdown of circTP63 inhibited GBC cells Epithelial-Mesenchymal Transition (EMT) process. In vivo, knockdown of circTP63 inhibited tumor growth in GBC. Mechanistically, we demonstrated that circTP63 competitively bind to miR-217 and promoted EZH2 expression and finally facilitated tumor progression.

Conclusions

Our findings demonstrated that circTP63 sponged to miR-217 and regulated EZH2 expression and finally facilitated tumor progression in GBC. Thus, targeting circTP63 may be a therapeutic strategy for the treatment of GBC.

Role of lncRNAs in the Development of an Aggressive Phenotype in Gallbladder Cancer

Long non-coding RNAs are sequences longer than 200 nucleotides that are involved in different normal and abnormal biological processes exerting their effect on proliferation and differentiation, among other cell features. Functionally, lncRNAs can regulate gene expression within the cells by acting at transcriptional, post-transcriptional, translational, or post-translational levels. However, in pathological conditions such as cancer, the expression of these molecules is deregulated, becoming elements that can help in the acquisition of tumoral characteristics in the cells that trigger carcinogenesis and cancer progression. Specifically, in gallbladder cancer (GBC), recent publications have shown that lncRNAs participate in the acquisition of an aggressive phenotype in cancer cells, allowing them to acquire increased malignant capacities such as chemotherapy resistance or metastasis, inducing a worse survival in these patients. Furthermore, lncRNAs are useful as prognostic and diagnostic biomarkers since they have been shown to be differentially expressed in tumor tissues and serum of individuals with GBC. Therefore, this review will address different lncRNAs that could be promoting malignant phenotypic characteristics in GBC cells and lncRNAs that may be useful as markers due to their capability to predict a poor prognosis in GBC patients.

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 Non-Coding RNA Myosin Light Chain Kinase Antisense 1 Plays an Oncogenic Role in Gallbladder Carcinoma by Promoting Chemoresistance and Proliferation

Background

Long non-coding RNAs (lncRNAs) have been reported to play critical roles in human tumours, including gallbladder carcinoma (GBC). However, their biological functions and molecular mechanisms in tumorigenesis and progression remain largely unknown.

Methods

Quantitative polymerase chain reaction (qPCR) was used to verify the expression of lncRNA myosin light chain kinase antisense RNA 1 (MYLK-AS1) in 120 pairs of GBC tissues and paired adjacent non-tumour tissues, as well as in six different GBC cell lines (NOZ, EH-GB1, OCUG-1, GBC-SD, SGC-996 and QBC-939). Cell counting kit 8 was applied to explore cell proliferation and drug sensitivity assays. The target miRNAs (miR) of MYLK-AS1 and downstream target genes were predicted using Starbase 3.0 software and confirmed by double luciferase reporting test. The expression of proteins was assessed using Western blot assay.

Results

Here, we demonstrated that MYLK-AS1 was significantly upregulated and correlated with a poor prognosis and poor clinical characteristics in GBC. Furthermore, the forced expression of MYLK-AS1 significantly promoted GBC cell proliferation and resistance to gemcitabine in vitro. Mechanistically, MYLK-AS1 functioned as an efficient miR-217 sponge, thereby releasing the inhibition of enhancer of zeste 2 polycomb repressive complex 2 (EZH2) subunit expression. MYLK-AS1 promoted GBC cell proliferation and resistance to gemcitabine by upregulating EZH2 expression, and EZH2 was confirmed as a direct target of miR-217.

Discussion

Our results confirmed that the chemoresistant driver MYLK-AS1 might be a promising candidate as a therapeutic target for the treatment of advanced GBC.

lncRNA OXCT1-AS1 Promotes Metastasis in Non-Small-Cell Lung Cancer by Stabilizing LEF1, In Vitro and In Vivo

Long noncoding RNAs (lncRNAs) play nonnegligible roles in the metastasis of non-small-cell lung cancer (NSCLC). This study is aimed at investigating the biological role of lncRNA OXCT1-AS1 in NSCLC metastasis and the underlying regulatory mechanisms. The expression profiles of lncRNA OXCT1-AS1 in different NSCLC cell lines were examined. Then, the biological function of lncRNA OXCT1-AS1 in NSCLC metastasis was explored by loss-of-function assays in vitro and in vivo. Further, the protective effect of lncRNA OXCT1-AS1 on lymphoid enhancer factor 1 (LEF1) was examined using RNA pull-down and RNA immunoprecipitation assays. Additionally, the role of LEF1 in NSCLC metastasis was investigated. Results indicated that lncRNA OXCT1-AS1 expression was significantly increased in NSCLC cell lines. Functional analysis revealed that knockdown of lncRNA OXCT1-AS1 impaired invasion and migration in vitro. Additionally, the ability of lncRNA OXCT1-AS1 to promote NSCLC metastasis was also confirmed in vivo. Mechanistically, through direct interaction, lncRNA OXCT1-AS1 maintained LEF1 stability by blocking NARF-mediated ubiquitination. Furthermore, LEF1 knockdown impaired invasion and migration of NSCLC in vitro and in vivo. Collectively, these data highlight the ability of lncRNA OXCT1-AS1 to promote NSCLC metastasis by stabilizing LEF1 and suggest that lncRNA OXCT1-AS1 represents a novel therapeutic target in NSCLC.

LncRNA MEG3 Alleviates Diabetic Cognitive Impairments by Reducing Mitochondrial-Derived Apoptosis through Promotion of FUNDC1-Related Mitophagy via Rac1-ROS Axis

Mitochondrial dysfunction and elevated ROS generation are predominant contributors of neuronal death that is responsible for the diabetes-related cognitive impairments. Emerging evidence has demonstrated that long noncoding RNA-MEG3 can serve as an important regulator in the pathogenesis of diabetes. However, the underlying mechanisms remain to be further clarified. Here, it was observed that MEG3 was significantly down-regulated in STZ (streptozotocin)-induced diabetic rats. MEG3 overexpression noticeably improved diabetes-induced cognitive dysfunctions, accompanied by the abatement of Rac1 activation and ROS production, as well as the inhibition of mitochondria-associated apoptosis. Furthermore, either MEG3 overexpression or Rac1 inhibition promoted FUNDC1 dephosphorylation and suppressed oxidative stress and neuro-inflammation. Similarly, in vitro studies confirmed that hyperglycemia also down-regulated MEG3 expression in PC12 cells. MEG3 reintroduction protected PC12 cells against hyperglycemia-triggered neurotoxicity by improving mitochondrial fitness and repressing mitochondria-mediated apoptosis. Moreover, these neuroprotective effects of MEG3 relied on FUNDC1-related mitophagy, since silencing of FUNDC1 abolished these beneficial outcomes. Additionally, MEG3 rescued HG-induced neurotoxicity was involved in inhibiting Rac1 expression via interaction with Rac1 3'UTR. Conversely, knockdown of MEG3 showed opposite effects. NSC23766, a specific inhibitor of Rac1, fully abolished harmful effects of MEG3 depletion. Consistently, knockdown of Rac1 potentiated FUNDC1-associated mitophagy. Meanwhile, colocalization of Rac1 and FUNDC1 was found in mitochondria under hyperglycemia, which was interrupted by MEG3 overexpression. Furthermore, silencing of Rac1 promoted PGAM5 expression, and FUNDC1 strongly interacted with LC3 in Rac1-deleted cells. Altogether, our findings suggested that the Rac1/ROS axis may be a downstream signaling pathway for MEG3-induced neuroprotection, which was involved in FUNDC1-associated mitophagy.

Loss of MIC60 Aggravates Neuronal Death by Inducing Mitochondrial Dysfunction in a Rat Model of Intracerebral Hemorrhage

Mitochondrial damage has been reported to be a critical factor for secondary brain injury (SBI) induced by intracerebral hemorrhage (ICH). MIC60 is a key element of the mitochondrial contact site and cristae junction organizing system (MICOS), which takes a principal part in maintaining mitochondrial structure and function. The role of MIC60 and its underlying mechanisms in ICH-induced SBI are not clear, which will be investigated in this present study. To establish and emulate ICH model in vivo and in vitro, autologous blood was injected into the right basal ganglia of Sprague-Dawley (SD) rats; and primary-cultured cortical neurons were treated by oxygen hemoglobin (OxyHb). First, after ICH induction, mitochondria were damaged and exhibited mitochondrial crista-structure remodeling, and MIC60 protein levels were reduced. Furthermore, MIC60 overexpression reduced ICH-induced neuronal death both in vivo and in vitro. In addition, MIC60 upregulation reduced ICH-induced cerebral edema, neurobehavioral impairment, and cognitive dysfunction; by contrast, MIC60 knockdown had the opposite effect. Additionally, in primary-cultured neurons, MIC60 overexpression could reverse ICH-induced neuronal cell death and apoptosis, mitochondrial membrane potential collapse, and decrease of mitophagy, indicating that MIC60 overexpression can maintain the integrity of mitochondrial structures. Moreover, loss of MIC60 is after ICH-induced reduction in PINK1 levels and mislocalization of Parkin in primary-cultured neurons. Taken together, our findings suggest that MIC60 plays an important role in ICH-induced SBI and may represent a promising target for ICH therapy.

LncRNA MYLK-AS1 acts as an oncogene by epigenetically silencing large tumor suppressor 2 (LATS2) in gastric cancer

Extensive studies showed the vital function of long noncoding RNAs (lncRNAs) in the pathological and physiological progression of tumors. Previous evidence has indicated that lncRNA MYLK Antisense RNA 1 (MYLK-AS1) acts as an oncogene to facilitate the progression of several tumors. Nevertheless, little is known about its biological role in gastric cancer (GC). Our report intended to probe the underlying mechanism and function of MYLK-AS1 in GC. Results revealed that MYLK-AS1 showed an upregulated level in GC. It was worth mentioning that upregulated MYLK-AS1 caused the unfavorable clinical outcome in GC patients. Functional assays indicated that MYLK-AS1 silencing retarded the proliferation, cell cycle, migration, and invasion in GC. Besides, in vivo assay validated that MYLK-AS1 deficiency also restrained tumor growth. Through in-depth mechanism exploration, MYLK-AS1 was uncovered to bind with wnhancer of zeste homolog 2 (EZH2), an epigenetic inhibitor, to inhibit the level of Large Tumor Suppressor 2 (LATS2), thereby exerting carcinogenicity. Conclusively, our research highlighted the importance of MYLK-AS1 in GC, indicating that MYLK-AS1 might be an effective biomarker for GC.

Long Non-coding RNA FIRRE Acts as a miR-520a-3p Sponge to Promote Gallbladder Cancer Progression via Mediating YOD1 Expression

OBJECTIVES

The role of lncRNAs in gallbladder cancer (GBC) remains poorly understood. In this study, we explored the function of functional intergenic repeating RNA element (FIRRE) in GBC.

MATERIALS AND METHODS

Whole transcriptome resequencing was performed in three pairs of GBC tissues and adjacent non-tumor tissues. lncRNA FIRRE expression was verified by real-time PCR. The function of FIRRE in GBC was evaluated by experiments in vitro and in vivo. The mechanism of FIRRE was investigated via fluorescent in situ hybridization, RNA pull-down, dual luciferase reporter assays, and RNA immunoprecipitation.

RESULTS

FIRRE level was dramatically increased in GBC tissues compared to that in the adjacent non-tumor tissues. High expression of FIRRE was closely related to clinical stage and poor prognosis in GBC patients. Moreover, FIRRE remarkably enhanced proliferation and migration, and inhibited apoptosis of GBC cells. Mechanistically, FIRRE modulated YOD1 expression by sponging miR-520a-3p, thus contributing to the development of GBC.

CONCLUSION

Our data revealed that FIRRE might act as a novel mediator in GBC progression by sponging miR-520a-3p and regulating YOD1. FIRRE might be regarded as a potential diagnostic marker or target for GBC treatment.

Non-coding RNAs and lipids mediate the function of extracellular vesicles in cancer cross-talk

Research on extracellular vesicles (EVs) has been expanded, especially in the field of cancer. The cargoes in EVs, especially those in small EVs such as exosomes include microRNAs (miRNAs), mRNA, proteins, and lipids, are assumed to work cooperatively in the tumor microenvironment. In 2007, it was reported that miRNAs were abundant among the non-coding RNAs present in exosomes. Since then, many studies have investigated the functions of miRNAs and have tried to apply these molecules to aid in the diagnosis of cancer. Accordingly, many reviews of non-coding RNAs in EVs have been published for miRNAs. This review focuses on relatively new cargoes, covering long noncoding (lnc) RNAs, circular RNAs, and repeat RNAs, among non-coding RNAs. These RNAs, regardless of EV or cell type, have newly emerged due to the innovation of sequencing technology. The poor conservation, low quantity, and technical difficulty in detecting these RNA types have made it difficult to elucidate their functions and expression patterns. We herein summarize a limited number of studies. Although lipids are major components of EVs, current research on EVs focuses on miRNA and protein biology, while the roles of lipids in exosomes have not drawn attention. However, several recent studies revealed that phospholipids, which are components of the EV membrane, play important roles in the intercommunication between cells and in the generation of lipid mediators. Here, we review the reported roles of these molecules, and describe their potential in cancer biology.

LncRNA EPB41L4A-AS2 represses Nasopharyngeal Carcinoma Metastasis by binding to YBX1 in the Nucleus and Sponging MiR-107 in the Cytoplasm

Nasopharyngeal carcinoma (NPC) is known for its potential to progress to the lymph nodes and distant metastases at an early stage. As an important regulator in tumorigenesis biological processes, the functions of lncRNA in NPC tumor development remain largely unclear. In this research, the expression of EPB41L4A-AS2 in NPC tissues and cells was analyzed via real-time quantitative polymerase chain reaction (qRT-PCR). CCK8, colony formation, and EDU experiments were used to determine the viability of NPC cells. Transwell and wound healing assays were performed to test NPC cell migration and invasion. RNA pull-down and mass spectrometry analysis were used to identify potential binding proteins. Then, a popliteal lymph node metastasis model was established to test NPC metastasis. EPB41L4A-AS2 is repressed by transforming growth factor-beta, which is downregulated in NPC cells and tissue. It is associated with the presence of distant metastasis and adverse outcomes. The univariate and multivariate survival assays confirmed that EPB41L4A-AS2 expression was an independent predictor of progression-free survival (PFS) in patients with NPC. Biological analyses showed that overexpression of EPB41L4A-AS2 reduced the metastasis and invasion of NPC in vitro and in vivo, but had no significant effect on cell proliferation. Mechanistically, in the nucleus we identified that EPB41L4A-AS2 relies on binding to YBX1 to reduce the stability of Snail mRNA to enhance the expression of E-cadherin and reverse the progression of epithelial-to-mesenchymal transition (EMT). In the cytoplasm, we found that EPB41L4A-AS2 blocked the invasion and migration of NPC cells by promoting LATS2 expression via sponging miR-107. In a whole, the findings of this study help to further understand the metastasis mechanism of NPC and could help in the prevention and treatment of NPC metastasis.

O-linked N-acetylglucosaminyltransferase OGT inhibits diabetic nephropathy by stabilizing histone methyltransferases EZH2 via the HES1/PTEN axis

BACKGROUND

O-linked N-acetylglucosaminyltransferase (OGT) is involved in diabetes-related diseases including diabetic nephropathy (DN), and responsible for O-GlcNAcylation. Moreover, O-GlcNAcylation and OGT could be induced by high glucose. Thus, we sought to explore the molecular mechanism of OGT in DN.

METHODS

Loss- and gain-functions were conducted to determine the roles of OGT, enhancer of zeste homolog 2 (EZH2), hairy and enhancer of split 1 (HES1) and phosphatase and tensin homolog (PTEN) in the viability, cell cycle and fibrosis of mesangial cells (MCs), followed by the assessment using 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, flow cytometry, and Western blot assay (fibrosis-related proteins). The interaction between OGT and EZH2 and the effect on EZH2 glycosylation were verified by chromatin immunoprecipitation (ChIP) and glutathione S-transferase (GST) pull-down assays. EZH2 stability was checked by treatment with cycloheximide.

RESULTS

Expression of OGT was repressed in the DN mice and high glucose-treated MCs. Elevated OGT suppressed viability of high glucose-treated MCs, blocked proliferation characterized by repressed cyclin D1, but enhanced p21 levels, and inhibited fibrosis evidenced by reduced levels of fibronectin (FN) and collagen-4 (col-4). OGT interacted with EZH2 and promoted its glycosylation thus stabilizing the EZH2. EZH2 overexpression enhanced the enrichment of EZH2 and histone H3 Lys27 trimethylation (H3K27me3) in the HES1 promoter. HES1 was upregulated and PTEN was downregulated in DN mice. Transduction of lentivirus vector containing overexpression (oe)-OGT alleviated renal injury in DN mice.

CONCLUSIONS

Collectively, OGT stabilizes histone methyltransferases EZH2 to regulate HES1/PTEN thus inhibiting DN.

Upregulation of LINC01426 promotes the progression and stemness in lung adenocarcinoma by enhancing the level of SHH protein to activate the hedgehog pathway

Long noncoding RNAs (lncRNAs) play crucial roles in regulating a variety of biological processes in lung adenocarcinoma (LUAD). In our study, we mainly explored the functional roles of a novel lncRNA long intergenic non-protein coding RNA 1426 (LINC01426) in LUAD. We applied bioinformatics analysis to find the expression of LINC01426 was upregulated in LUAD tissue. Functionally, silencing of LINC01426 obviously suppressed the proliferation, migration, epithelial-mesenchymal transition (EMT), and stemness of LUAD cells. Then, we observed that LINC01426 functioned through the hedgehog pathway in LUAD. The effect of LINC01426 knockdown could be fully reversed by adding hedgehog pathway activator SAG. In addition, we proved that LINC01426 could not affect SHH transcription and its mRNA level. Pull-down sliver staining and RIP assay revealed that LINC01426 could interact with USP22. Ubiquitination assays manifested that LINC01426 and USP22 modulated SHH ubiquitination levels. Rescue assays verified that SHH overexpression rescued the cell growth, migration, and stemness suppressed by LINC01426 silencing. In conclusion, LINC01426 promotes LUAD progression by recruiting USP22 to stabilize SHH protein and thus activate the hedgehog pathway.

Molecular Classification and Tumor Microenvironment Characterization of Gallbladder Cancer by Comprehensive Genomic and Transcriptomic Analysis

Simple Summary

Gallbladder cancer (GBC) is a rare but lethal cancer. Molecular characterization of GBC is insufficient so far, and a comprehensive molecular portrait is warranted to uncover new targets and classify GBC. Clustering analysis of RNA expression revealed two subclasses of 36 GBCs, which reflects the status of the tumor microenvironment (TME) and poor prognosis of GBC, including epithelial–mesenchymal transition (EMT), immune suppression, and the TGF-β signaling pathway. The knockout of miR125B1 in GBC cell lines decreased its invasion ability and altered the EMT pathway. Mutations of the genes related to the TGF-β signaling pathway were enriched in the poor-prognosis/TME-rich cluster of GBCs. This comprehensive molecular analysis provides a new classification of GBCs based on the TME activity, which is involved with EMT and immune suppression for poor prognosis of GBC. This information may be useful for GBC prognosis and therapeutic decision-making.

Abstract

Gallbladder cancer (GBC), a rare but lethal disease, is often diagnosed at advanced stages. So far, molecular characterization of GBC is insufficient, and a comprehensive molecular portrait is warranted to uncover new targets and classify GBC. We performed a transcriptome analysis of both coding and non-coding RNAs from 36 GBC fresh-frozen samples. The results were integrated with those of comprehensive mutation profiling based on whole-genome or exome sequencing. The clustering analysis of RNA-seq data facilitated the classification of GBCs into two subclasses, characterized by high or low expression levels of TME (tumor microenvironment) genes. A correlation was observed between gene expression and pathological immunostaining. TME-rich tumors showed significantly poor prognosis and higher recurrence rate than TME-poor tumors. TME-rich tumors showed overexpression of genes involved in epithelial-to-mesenchymal transition (EMT) and inflammation or immune suppression, which was validated by immunostaining. One non-coding RNA, miR125B1, exhibited elevated expression in stroma-rich tumors, and miR125B1 knockout in GBC cell lines decreased its invasion ability and altered the EMT pathway. Mutation profiles revealed TP53 (47%) as the most commonly mutated gene, followed by ELF3 (13%) and ARID1A (11%). Mutations of ARID1A, ERBB3, and the genes related to the TGF-β signaling pathway were enriched in TME-rich tumors. This comprehensive analysis demonstrated that TME, EMT, and TGF-β pathway alterations are the main drivers of GBC and provides a new classification of GBCs that may be useful for therapeutic decision-making.

MKL1-induced lncRNA SNHG18 drives the growth and metastasis of non-small cell lung cancer via the miR-211-5p/BRD4 axis

Megakaryocytic leukemia 1 (MKL1) is a key transcription factor involved in non-small cell lung cancer (NSCLC) growth and metastasis. Yet, its downstream target genes, especially long non-coding RNA (lncRNA) targets, are poorly investigated. In this study, we employed lncRNA array technology to identify differentially expressed lncRNAs in NSCLC cells with or without overexpression of MKL1. Candidate lncRNAs were further explored for their clinical significance and function in NSCLC. The results showed that MKL1 promoted the expression of lncRNA SNHG18 in NSCLC cells. SNHG18 upregulation in NSCLC specimens correlated with lymph node metastasis and reduced overall survival of NSCLC patients. SNHG18 expression served as an independent prognostic factor for NSCLC. Knockdown of SNHG18 blocked MKL1-induced growth and invasion of NSCLC cells in vitro. Animal studies validated the requirement for SNHG18 in NSCLC growth and metastasis. Moreover, overexpression of SNHG18 promoted NSCLC cell proliferation and invasion. Mechanically, SNHG18 exerted its prometastatic effects on NSCLC cells through repression of miR-211-5p and induction of BRD4. Clinical evidence indicated that SNHG18 expression was negatively correlated with miR-211-5p expression in NSCLC tissues. Altogether, SNHG18 acts as a lncRNA mediator of MKL1 in NSCLC. SNHG18 facilitates NSCLC growth and metastasis by modulating the miR-211-5p/BRD4 axis. Therefore, SNHG18 may be a potential therapeutic target for the treatment of NSCLC.

Current and New Biomarkers for Early Detection, Prognostic Stratification, and Management of Gallbladder Cancer Patients

Gallbladder cancer (GBC) is an aggressive disease that shows evident geographic variation and is characterized by a poor prognosis, mainly due to the late diagnosis and ineffective treatment. Genetic variants associated with GBC susceptibility, including polymorphisms within the toll-like receptors TLR2 and TLR4, the cytochrome P450 1A1 (CYP1A1), and the ATP-binding cassette (ABC) transporter ABCG8 genes, represent promising biomarkers for the stratification of patients at higher risk of GBC; thus, showing potential to prioritize cholecystectomy, particularly considering that early diagnosis is difficult due to the absence of specific signs and symptoms. Similarly, our better understanding of the gallbladder carcinogenic processes has led to identify several cellular and molecular events that may influence patient management, including HER2 aberrations, high tumor mutational burden, microsatellite instability, among others. Despite these reports on interesting and promising markers for risk assessment, diagnosis, and prognosis; there is an unmet need for reliable and validated biomarkers that can improve the management of GBC patients and support clinical decision-making. This review article examines the most potentially significant biomarkers of susceptibility, diagnosis, prognosis, and therapy selection for GBC patients, highlighting the need to find and validate existing and new molecular biomarkers to improve patient outcomes.

Long noncoding RNA HOXA-AS2 functions as an oncogene by binding to EZH2 and suppressing LATS2 in acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is the most common hematological malignancy in the world. Long noncoding RNAs (lncRNAs) play an important role in the development of physiology and pathology. Many reports have shown that lncRNA HOXA cluster antisense RNA 2 (HOXA-AS2) is a carcinogen and plays an important role in many tumors, but little is known about its role in AML. The aim of this study was to explore the potential mechanism and role of HOXA-AS2 in AML. HOXA-AS2 was upregulated in AML cell lines and tissues, and the overexpression of HOXA-AS2 is negatively correlated with the survival of patients. Silencing HOXA-AS2 can inhibit the proliferation and induce differentiation of AML cells in vitro and in vivo. Overexpressing HOXA-AS2 showed the opposite result. Moreover, more in-depth mechanism studies showed that carcinogenicity of HOXA-AS2 exerted mainly through binding with the epigenetic inhibitor Enhancer of zeste homolog 2 (EZH2) and then inhibiting the expression of Large Tumor Suppressor 2 (LATS2). Taken together, our findings highlight the important role of HOXA-AS2 in AML, suggesting that HOXA-AS2 may be an effective therapeutic target for patients with AML.

A systematic review with in silico analysis on transcriptomic profile of gallbladder carcinoma

Gallbladder cancer (GBC) is an aggressive malignancy of the biliary tract. It is asymptomatic in its early stages, and often, characterized by a poor prognosis and worse treatment response. Distribution of GBC shows both geographical as well as ethnic variations. Several studies have elucidated the differential gene expression profile between the normal gallbladder and GBCs, with varied but inconsistent results. Thus, a deep understanding of the expression profile of GBC might aid in the identification of potential biomarkers, which would further help in better disease management and appropriate therapy selection. This review summarizes studies on the transcriptomic profile of GBC with emphasis on studies pertaining to coding (mRNA) and noncoding (micro and long noncoding) RNA along with aberrant promoter methylation studies, ranging from a single gene to global gene to high throughput RNA sequencing approaches, published between 2000 to May, 2019. In addition, data mining of GBC from the available public functional genomics data repository at Gene Expression Omnibus has been done to rule out potentially important dysregulated genes in this malignancy. To the best of our knowledge, this is the first article to shed light on the RNA based gene regulatory network(s) along with bioinformatic analysis. Moreover, this review represents major research challenges and ambiguity, knowledge of which is a must for establishing molecular/ clinical biomarkers for early GBC diagnosis, management, and treatment protocols.

Roles of Non-Coding RNAs on Anaplastic Thyroid Carcinomas

Anaplastic thyroid cancer (ATC) remains as one of the most aggressive human carcinomas with poor survival rates in patients with the cancer despite therapeutic interventions. Novel targeted and personalized therapies could solve the puzzle of poor survival rates of patients with ATC. In this review, we discuss the role of non-coding RNAs in the regulation of gene expression in ATC as well as how the changes in their expression could potentially reshape the characteristics of ATCs. A broad range of miRNA, such as miR-205, miR-19a, miR-17-3p and miR-17-5p, miR-618, miR-20a, miR-155, etc., have abnormal expressions in ATC tissues and cells when compared to those of non-neoplastic thyroid tissues and cells. Moreover, lncRNAs, such as H19, Human leukocyte antigen (HLA) complex P5 (HCP5), Urothelial carcinoma-associated 1 (UCA1), Nuclear paraspeckle assembly transcript 1 (NEAT1), etc., participate in transcription and post-transcriptional regulation of gene expression in ATC cells. Dysregulations of these non-coding RNAs were associated with development and progression of ATC by modulating the functions of oncogenes during tumour progression. Thus, restoration of the abnormal expression of these miRNAs and lncRNAs may serve as promising ways to treat the patients with ATC. In addition, siRNA mediated inhibition of several oncogenes may act as a potential option against ATC. Thus, non-coding RNAs can be useful as prognostic biomarkers and potential therapeutic targets for the better management of patients with ATC.

Hypermethylation of LATS2 Promoter and Its Prognostic Value in IDH-Mutated Low-Grade Gliomas

Mutations in the enzyme isocitrate dehydrogenase 1/2 (IDH1/2) are the most common somatic mutations in low-grade glioma (LGG). The Hippo signaling pathway is known to play a key role in organ size control, and its dysregulation is involved in the development of diverse cancers. Large tumor suppressor 1/2 (LATS1/2) are core Hippo pathway components that phosphorylate and inactivate Yes-associated protein (YAP), a transcriptional co-activator that regulates expression of genes involved in tumorigenesis. A recent report from The Cancer Genome Atlas (TCGA) has highlighted a frequent hypermethylation of LATS2 in IDH-mutant LGG. However, it is unclear if LATS2 hypermethylation is associated with YAP activation and prognosis of LGG patients. Here, we performed a network analysis of the status of the Hippo pathway in IDH-mutant LGG samples and determined its association with cancer prognosis. Combining TCGA data with our biochemical assays, we found hypermethylation of LATS2 promoter in IDH-mutant LGG. LATS2 hypermethylation, however, did not translate into YAP activation but highly correlated with IDH mutation. LATS2 hypermethylation may thus serve as an alternative for IDH mutation in diagnosis and a favorable prognostic factor for LGG patients.

Long noncoding RNA PVT1 promoted gallbladder cancer proliferation by epigenetically suppressing miR-18b-5p via DNA methylation

Gallbladder cancer (GBC) accounts for 85-90% malignancies of the biliary tree worldwide. Considerable evidence has demonstrated that dysregulation of lncRNAs is involved in the progression of cancer. LncRNA PVT1 has been reported to play important roles in various cancers, but its role in gallbladder cancer remains unknown. In the present study, we found that PVT1 was upregulated in GBC tissues and cells, and its upregulation was related with poor prognosis in GBC patients. PVT1 promoted GBC cells proliferation in vitro and in vivo. Mechanistically, PVT1 recruited DNMT1 via EZH2 to the miR-18b-5p DNA promoter and suppressed the transcription of miR-18b-5p through DNA methylation. Moreover, HIF1A was proved to be the downstream target gene of miR-18b-5p and PVT1 regulated GBC cells proliferation via HIF1A. In conclusion, our studies clarified the PVT1/miR-18b-5p/HIF1A regulation axis and indicated that PVT1 could be a potential therapeutic target for GBC.

Downregulation of MEG3 promotes neuroblastoma development through FOXO1-mediated autophagy and mTOR-mediated epithelial-mesenchymal transition

Our previous studies demonstrated that MEG3 was significantly downregulated in neuroblastoma (NB) and its expression was negatively associated with the INSS stage. Overexpression of MEG3 promoted apoptosis and inhibited proliferation in NB cells. In this study, we discovered more potential functions and molecular mechanisms of MEG3 in NB. According to the database, MEG3 positively correlated with the NB survival rate and was negatively associated with malignant clinical features. Moreover, we determined that MEG3 was mainly located in the nucleus by nuclear-cytoplasmic separation and RNA fish assays. Upregulation of MEG3 in stably transfected cell lines was accomplished, and CCK8, colony formation, and EDU assays were performed, which indicated that MEG3 significantly suppressed cell proliferation. Both wound healing and transwell experiments demonstrated that MEG3 decreased cell migration and invasion. CHIRP enrichments showed the anticancer effects of MEG3 were probably linked to autophagy and the mTOR signaling pathway. LC3 fluorescence dots and western blots showed that MEG3 attenuated autophagy by inhibiting FOXO1, but not the mTOR signaling pathway. Furthermore, MEG3 inhibited metastasis through epithelial-mesenchymal transition via the mTOR signaling pathway. Consistent with the above results, downregulation of MEG3 facilitated NB malignant phenotypes. Mechanistically, MEG3 and EZH2 regulated each other via a negative feedback loop and promoted NB progression together. In conclusion, our findings suggested that MEG3 was a tumor suppressor in NB and could be a potential target for NB treatment in the future.

Therapeutic potential of extracellular vesicle-associated long noncoding RNA

Both extracellular vesicles (EVs) and long noncoding RNAs (lncRNAs) have been increasingly investigated as biomarkers, pathophysiological mediators, and potential therapeutics. While these two entities have often been studied separately, there are increasing reports of EV-associated lncRNA activity in processes such as oncogenesis as well as tissue repair and regeneration. Given the powerful nature and emerging translational impact of other noncoding RNAs such as microRNA (miRNA) and small interfering RNA, lncRNA therapeutics may represent a new frontier. While EVs are natural vehicles that transport and protect lncRNAs physiologically, they can also be engineered for enhanced cargo loading and therapeutic properties. In this review, we will summarize the activity of lncRNAs relevant to both tissue repair and cancer treatment and discuss the role of EVs in enabling the potential of lncRNA therapeutics.

The emerging role of lncRNAs in multiple sclerosis

Multiple sclerosis (MS) is the most common inflammatory demyelinating disease of the central nervous system (CNS) with various clinical manifestations. The characteristic of MS is that myelin is attacked by the body's immune system and increases the electrical capacity of axons, and is the primary pathophysiological mechanism of the transmission block. Studies have shown that epigenetic factors participate in the development of MS. LncRNAs are highly abundant and heterogeneous linear RNA transcripts with lengths exceeding 200 nucleotides and no protein-coding potential. Currently, pieces of evidence have demonstrated that lncRNAs have fundamental actions in multiple cellular pathways, including immune system regulation, epithelial-mesenchymal transition (EMT), cancer cell growth and metastasis, cellular homeostasis, and embryo development. It has been demonstrated that epigenetic mechanisms have an abundant role in the pathogenesis of MS in which the role of lncRNAs as epigenetic regulatory molecules in molecular processes has been proven. In this paper, we have focused on the correlation between MS and lncRNAs, the role of lncRNA in the pathogenesis of the disease, and the diagnostic and prognostic potential of lncRNA in MS.

Long non-coding RNA MEG3 promotes fibrosis and inflammatory response in diabetic nephropathy via miR-181a/Egr-1/TLR4 axis

Long non-coding RNAs (lncRNAs) play vital roles in diabetic nephropathy (DN). This research aimed to study the potential role and underlying molecular mechanisms of long non-coding RNA MEG3 in DN. We found that MEG3 was upregulated in DN in vivo and in vitro and could enhance cell fibrosis and inflammatory response in DN. MEG3 functioned as an endogenous sponge for miR-181a in mesangial cells (MCs) via direct targeting and in an Ago2-dependent manner. MiR-181a inhibition promoted MC fibrosis and inflammatory response. In addition, Egr-1 was confirmed as a target gene of miR-181a. Further investigations verified that MEG3 promotes fibrosis and inflammatory response via the miR-181a/Egr-1/TLR4 axis in vitro and in vivo. These results provide new insights into the regulation between MEG3 and the miR-181a/Egr-1/TLR4 signaling pathway during DN progression.

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

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

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.