[Retracted] MEG3/miR­21 axis affects cell mobility by suppressing epithelial­mesenchymal transition in gastric cancer.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that certain of the Transwell cell invasion assay data shown in Fig. 2B on p. 42 and the immunofluorescence data shown in Fig. 4D on p. 44 were strikingly similar to data appearing in other articles written by different authors at different research institutes that were submitted to different journals at around the same time. Moreover, a further investigation of this paper undertaken by the Editorial Office identified a large number of overlapping data panels comparing the Transwell cell migration and invasion assay data and the scratch­wound assay data both within and between Figs. 2 and 3, where data which were intended to have shown the results from differently performed experiments had apparently been derived from the same original source, including an overlapping section of data within the 'MEG3+mimic' panel in Fig. 3G that would be difficult to attribute to pure chance. Owing to the fact that the contentious data in the above article had already been submitted for publication at around the same time as its submission to Oncology Reports, and given an overall lack of confidence in the presented data, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 40: 39­48, 2018; DOI: 10.3892/or.2018.6424].

Harnessing the TP53INP1/TP53I3 axis for inhibition of colorectal cancer cell proliferation through MEG3 and Linc-ROR Co-expression.

Dysregulation of long noncoding RNAs (lncRNAs), such as maternally expressed gene 3 (MEG3) and long intergenic noncoding RNA regulator of reprogramming (linc-ROR), plays a crucial role in colorectal cancer progression. We aimed to assess linc-ROR silencing and MEG3 activation on the colorectal cancer cell proliferation simultaneously; and explore the underlying mechanisms in the TP53-associated Pathway. The MEG3 and linc-ROR shRNA were cloned under the bidirectional CEA promoter (UM1). Subsequently, additional vectors were constructed to express linc-ROR shRNA (UM2) and MEG3 (UM3). After transfecting colorectal cancer cell lines with these recombinant vectors, experiments on cell viability, apoptosis, and cell cycle analysis were conducted. Furthermore, TP53's transcriptional activity and associated genes were assessed using quantitative real-time polymerase chain reaction (qRT-PCR). Interestingly, UM1 significantly inhibited the proliferation of both cell lines than UM2 and UM3. In response to UM1, TP53 transcript remarkably increased in HCT116 cells (10.46) than SW480 cells (6.16); which resulted in up-regulation of TP53INP1, TP53I3, GDF15, CCKN1A and BAX, and down-regulation of G1 cyclins (D1, E1). The rate of apoptosis increased in HCT116 (36.35 %) and SW480 (16.64 %) cells than control. Moreover, UM1-transfected HCT116 cells exhibited a notable arrest in the G0/G1 phase, accompanied by a reduction in the G2/M cell population. Compared to unidirectional vectors, the concurrent targeting approach enhanced TP53 activation at the transcription level. The cell response to UM1 resulted in rapid upregulation of TP53, leading to inhibition of cell proliferation, increased apoptosis, and cell cycle arrest. These findings suggest that the synergistic effect of targeting both MEG3 and linc-ROR could serve as a promising therapeutic strategy for TP53-associated colon cancer.

A possible role of lncRNA MEG3 and lncRNA MAFG-AS1 on miRNA 147-b in the pathogenesis of Behcet's disease.

Behcet's disease (BD) is a multisystem disease with altered Toll-like receptors (TLRs) on macrophages. Long noncoding RNA Maternally expressed gene 3 (lncRNA MEG3) and lncRNA Musculoaponeurotic fibrosarcoma oncogene family, protein G antisense 1 (MAFG-AS1) are regulators of microRNA (miRNA) 147-b, which is induced upon TLR stimulation. We included fifty BD patients, and fifty age and sex-matched controls. Real-time polymerase chain reaction (PCR) was used to measure the expression levels of serum lncRNA MEG3, lncRNA MAFG-AS1, and miRNA 147-b. LncRNA MEG3 and lncRNA MAFG-AS1 were significantly downregulated while miRNA 147-b was significantly upregulated in the BD patients' serum compared to the controls with p-value <0.001. Receiver operation characteristics (ROC) curve analysis revealed that the three biomarkers can discriminate between BD and control subjects with 76%, 100%, and 70% sensitivity respectively, and 100% specificity for all of them. There was a lower expression level of lnc RNA MEG3 among patients who had new eye involvement in the last month in comparison to those without new eye involvement (p-value=0.017). So, LncRNA MEG3, lncRNA MAFG-AS1, and miRNA147-b are promising diagnostic markers and therapeutic targets for BD patients. LncRNA MEG3 can be used as a predictor for new BD ocular involvement.

Transgenerational epigenetic self-memory of Dio3 dosage is associated with Meg3 methylation and altered growth trajectories and neonatal hormones.

Intergenerational and transgenerational epigenetic effects resulting from conditions in previous generations can contribute to environmental adaptation as well as disease susceptibility. Previous studies in rodent and human models have shown that abnormal developmental exposure to thyroid hormone affects endocrine function and thyroid hormone sensitivity in later generations. Since the imprinted type 3 deiodinase gene (Dio3) regulates sensitivity to thyroid hormones, we hypothesize its epigenetic regulation is altered in descendants of thyroid hormone overexposed individuals. Using DIO3-deficient mice as a model of developmental thyrotoxicosis, we investigated Dio3 total and allelic expression and growth and endocrine phenotypes in descendants. We observed that male and female developmental overexposure to thyroid hormone altered total and allelic Dio3 expression in genetically intact descendants in a tissue-specific manner. This was associated with abnormal growth and neonatal levels of thyroid hormone and leptin. Descendant mice also exhibited molecular abnormalities in the Dlk1-Dio3 imprinted domain, including increased methylation in Meg3 and altered foetal brain expression of other genes of the Dlk1-Dio3 imprinted domain. These molecular abnormalities were also observed in the tissues and germ line of DIO3-deficient ancestors originally overexposed to thyroid hormone in utero. Our results provide a novel paradigm of epigenetic self-memory by which Dio3 gene dosage in a given individual, and its dependent developmental exposure to thyroid hormone, influences its own expression in future generations. This mechanism of epigenetic self-correction of Dio3 expression in each generation may be instrumental in descendants for their adaptive programming of developmental growth and adult endocrine function.

Genetic variants of LncRNAs HOTTIP and MEG3 influence nasopharyngeal carcinoma susceptibility and clinicopathologic characteristics in the Southern Chinese population.

OBJECTIVE: Recent studies have indicated that HOTTIP and MEG3 are associated with the initiation and progression of various types of tumors, including nasopharyngeal carcinoma (NPC). This investigation aimed to elucidate the impact of HOTTIP and MEG3 polymorphisms on the susceptibility and clinicopathologic characteristics of NPC. METHODS: This research employed next-generation sequencing and multiplex PCR to assess the polymorphisms of HOTTIP rs1859168 and MEG3 rs7158663 in 200 NPC and 200 healthy individuals respectively. HOTTIP and MEG3 expression were assessed via qRT-PCR assessment. Furthermore, the genotypes and alleles frequency of rs1859168 and rs7158663 were compared between healthy and NPC individuals to elucidate their influence on NPC susceptibility and relation with clinicopathologic characteristics. RESULTS: In comparison with the healthy cohort, the presence of HOTTIP rs1859168 CC genotype and the C allele were markedly linked with increased NPC incidence (p < 0.05). Furthermore, the MEG3 rs7158663 AA genotype and the A allele also indicated an increased risk of NPC (p < 0.05). The subgroup analysis of age, EBV infection, gender, nationality, smoking, and drinking status revealed no marked association between rs1859168 and rs7158663 genotypes and these potential confounding factors. Moreover, it was observed that rs1859168 CC and rs7158663 AA genotypes were related to local tumor invasion and lymph node metastasis. Additionally, HOTTIP indicated a marked elevation, while MEG3 substantially reduced in NPC samples than the normal nasopharyngeal biospecimens. Patients who carried CC or CA genotypes rather than the HOTTIP rs1859168 AA genotype, had substantially higher HOTTIP levels, while patients with rs7158663 AA or GA genotypes indicated notably lower expression of MEG3 than GG genotype carriers. CONCLUSION: Individuals with genetic variants of HOTTIP rs1859168 and MEG3 rs7158663 might have an increased risk of NPC susceptibility and related clinicopathologic characteristics, potentially by affecting the expression of HOTTIP and MEG3.

Caenorhabditis elegans germ granules accumulate hundreds of low translation mRNAs with no systematic preference for germ cell fate regulators.

In animals with germ plasm, embryonic germline precursors inherit germ granules, condensates proposed to regulate mRNAs coding for germ cell fate determinants. In Caenorhabditis elegans, mRNAs are recruited to germ granules by MEG-3, a sequence non-specific RNA-binding protein that forms stabilizing interfacial clusters on germ granules. Using fluorescence in situ hybridization, we confirmed that 441 MEG-3-bound transcripts are distributed in a pattern consistent with enrichment in germ granules. Thirteen are related to transcripts reported in germ granules in Drosophila or Nasonia. The majority, however, are low-translation maternal transcripts required for embryogenesis that are not maintained preferentially in the nascent germline. Granule enrichment raises the concentration of certain transcripts in germ plasm but is not essential to regulate mRNA translation or stability. Our findings suggest that only a minority of germ granule-associated transcripts contribute to germ cell fate in C. elegans and that the vast majority function as non-specific scaffolds for MEG-3.

GNAS mutations suppress cell invasion by activating MEG3 in growth hormone-secreting pituitary adenoma.

Approximately 30%-40% of growth hormone-secreting pituitary adenomas (GHPAs) harbor somatic activating mutations in GNAS (α subunit of stimulatory G protein). Mutations in GNAS are associated with clinical features of smaller and less invasive tumors. However, the role of GNAS mutations in the invasiveness of GHPAs is unclear. GNAS mutations were detected in GHPAs using a standard polymerase chain reaction (PCR) sequencing procedure. The expression of mutation-associated maternally expressed gene 3 (MEG3) was evaluated with RT-qPCR. MEG3 was manipulated in GH3 cells using a lentiviral expression system. Cell invasion ability was measured using a Transwell assay, and epithelial-mesenchymal transition (EMT)-associated proteins were quantified by immunofluorescence and western blotting. Finally, a tumor cell xenograft mouse model was used to verify the effect of MEG3 on tumor growth and invasiveness. The invasiveness of GHPAs was significantly decreased in mice with mutated GNAS compared with that in mice with wild-type GNAS. Consistently, the invasiveness of mutant GNAS-expressing GH3 cells decreased. MEG3 is uniquely expressed at high levels in GHPAs harboring mutated GNAS. Accordingly, MEG3 upregulation inhibited tumor cell invasion, and conversely, MEG3 downregulation increased tumor cell invasion. Mechanistically, GNAS mutations inhibit EMT in GHPAs. MEG3 in mutated GNAS cells prevented cell invasion through the inactivation of the Wnt/ß-catenin signaling pathway, which was further validated in vivo. Our data suggest that GNAS mutations may suppress cell invasion in GHPAs by regulating EMT through the activation of the MEG3/Wnt/ß-catenin signaling pathway.

Long non-coding RNA MEG3 knockdown represses airway smooth muscle cells proliferation and migration via sponging miR-143-3p/FGF9 in asthma.

BACKGROUND: Asthma is a respiratory disease characterized by airway remodeling. We aimed to find out the role and mechanism of lncRNA MEG3 in asthma. METHODS: We established a cellular model of asthma by inducing human airway smooth muscle cells (HASMCs) with PDGF-BB, and detected levels of lncRNA MEG3, miR-143-3p and FGF9 in HASMCs through qRT-PCR. The functions of lncRNA MEG3 or miR-143-3p on HASMCs were explored by cell transfection. The binding sites of miR-143-3p and FGF9 were subsequently analyzed with bioinformatics software, and validated with dual-luciferase reporter assay. MTT, 5-Ethynyl-2'-deoxyuridine (EdU) assay, and Transwell were used to detect the effects of lncRNA MEG3 or miR-143-3p on proliferation and migration of HASMCs. QRT-PCR and western blot assay were used to evaluate the level of proliferation-related marker PCNA in HASMCs. RESULTS: The study found that lncRNA MEG3 negatively correlated with miR-143-3p, and miR-143-3p could directly target with FGF9. Silence of lncRNA MEG3 can suppress migration and proliferation of PDGF-BB-induced HASMCs via increasing miR-143-3p. Further mechanistic studies revealed that miR-143-3p negatively regulated FGF9 expression in HASMCs. MiR-143-3p could inhibit PDGF-BB-induced HASMCs migration and proliferation through downregulating FGF9. CONCLUSION: LncRNA MEG3 silencing could inhibit the migration and proliferation of HASMCs through regulating miR-143-3p/FGF9 signaling axis. These results imply that lncRNA MEG3 plays a protective role against asthma.

LncRNA MEG3 regulates ferroptosis of lens epithelial cells via PTBP1/GPX4 axis to participate in age-related cataract.

Age-related cataract (ARC) is regarded as the principal cause of vision impairment among the aged. The regulatory role of long noncoding RNAs (LncRNAs) in ARC remains unclear. The lncRNA maternally expressed gene 3 (MEG3) has been reported to promote ARC progression, and the underlying mechanism was further investigated in this study. Lens epithelium samples were collected to verify the expression of MEG3. Lens epithelial cells (LECs) were treated with H2O2 to mimic microenvironment of ARC in vitro. Cell viability, reactive oxygen species, and ferroptosis were evaluated during the in viro experiments. In the present work, lncRNA MEG3 was highly expressed in ARC group, compared with normal group. MEG3 was induced, cell viability and glutathione peroxidase 4 (GPX4) level were inhibited, and ferroptosis was promoted in H2O2 treated LECs. LncRNA MEG3 silence reversed the effects of H2O2 on viability and ferroptosis in LECs. Thereafter, lncRNA MEG3 was found to bind to PTBP1 for GPX4 degradation. Silencing of GPX4 reversed the regulation of lncRNA MEG3 inhibition in H2O2-treated LECs. To sum up, lncRNA MEG3 exhibited high expression in ARC. In H2O2-induced LECs, inhibition of lncRNA MEG3 accelerated cell viability and repressed ferroptosis by interaction with PTBP1 for GPX4 messenger RNA decay. Targeting lncRNA MEG3 may be a novel treatment of ARC.

Cigarette Smoke Extract-Treated Mouse Airway Epithelial Cells-Derived Exosomal LncRNA MEG3 Promotes M1 Macrophage Polarization and Pyroptosis in Chronic Obstructive Pulmonary Disease by Upregulating TREM-1 via m6A Methylation.

Cigarette smoke extract (CSE)-treated mouse airway epithelial cells (MAECs)-derived exosomes accelerate the progression of chronic obstructive pulmonary disease (COPD) by upregulating triggering receptor expressed on myeloid cells 1 (TREM-1); however, the specific mechanism remains unclear. We aimed to explore the potential mechanisms of CSE-treated MAECs-derived exosomes on M1 macrophage polarization and pyroptosis in COPD. In vitro, exosomes were extracted from CSE-treated MAECs, followed by co-culture with macrophages. In vivo, mice exposed to cigarette smoke (CS) to induce COPD, followed by injection or/and intranasal instillation with oe-TREM-1 lentivirus. Lung function and pathological changes were evaluated. CD68+ cell number and the levels of iNOS, TNF-α, IL-1ß (M1 macrophage marker), and pyroptosis-related proteins (NOD-like receptor family pyrin domain containing 3, apoptosis-associated speck-like protein containing a caspase-1 recruitment domain, caspase-1, cleaved-caspase-1, gasdermin D [GSDMD], and GSDMD-N) were examined. The expression of maternally expressed gene 3 (MEG3), spleen focus forming virus proviral integration oncogene (SPI1), methyltransferase 3 (METTL3), and TREM-1 was detected and the binding relationships among them were verified. MEG3 increased N6-methyladenosine methylation of TREM-1 by recruiting SPI1 to activate METTL3. Overexpression of TREM-1 or METTL3 negated the alleviative effects of MEG3 inhibition on M1 polarization and pyroptosis. In mice exposed to CS, EXO-CSE further aggravated lung injury, M1 polarization, and pyroptosis, which were reversed by MEG3 inhibition. TREM-1 overexpression negated the palliative effects of MEG3 inhibition on COPD mouse lung injury. Collectively, CSE-treated MAECs-derived exosomal long non-coding RNA MEG3 may expedite M1 macrophage polarization and pyroptosis in COPD via the SPI1/METTL3/TREM-1 axis.

MEG3 rs7158663 genetic polymorphism is associated with the risk of hepatocellular carcinoma.

Recently, a meta-analysis has shown that a potentially functional genetic polymorphism (rs7158663 A > G) on the cancer-associated lncRNA MEG3 is associated with the risk of many types of cancer. Given the important role of MEG3 in the development of hepatocellular carcinoma (HCC), the current study evaluated the association of the rs7158663 genetic polymorphism with HCC risk. A total of 271 HCC patients and 267 healthy individuals were included in the current case-control study. Direct sequencing was used to detect the rs7158663 locus genotype of the included individuals. The case-control study showed that the MEG3 rs7158663 genetic polymorphism was associated with the increased risk of developing HCC [GA vs. GG: OR = 1.63, 95% CI = 1.14-2.34, p = 0.009; AA vs. GG: OR = 2.10, 95% CI = 1.10-4.08, p = 0.03; (GA + AA) vs. GG: OR = 1.70, 95% CI = 1.21-2.40, p = 0.003; A vs. G: OR = 1.53, 95% CI = 1.17-2.00, p = 0.002]. In addition, the genotype-tissue expression showed that the rs7158663 AA or GA genotype was associated with reduced MEG3 expression. Bioinformatic analysis showed that the rs7158663 genetic polymorphism not only affects the binding of transcription factors but also interacts with multiple genes through chromatin loops. In summary, the current findings suggest that the rs7158663 genetic polymorphism affecting MEG3 expression is associated with HCC risk and may serve as a marker of genetic susceptibility to HCC. However, the specific molecular mechanisms of the rs7158663 genetic polymorphism in the development of HCC need to be further revealed.

Study of lncRNAs expression profile in the response to biological drugs in Psoriatic Arthritis: MEG3 could be a potential genomic biomarker of therapy efficacy.

We aimed to identify an expression profile of lncRNAs potentially related to treatment response in Psoriatic arthritis (PsA) patients, to be used as potential genomic biomarkers predictors of drug treatment effectiveness. In addition, we evaluated a possible association between lncRNAs genetic variants and the response to therapy using the clinical parameter of Disease Activity Index. For the expression study, we collected 48 treated PsA patients, monitoring the treatment response for 12 months. We initially used PCR Array and, then, we validated the results with qRT-PCR. We also retrospectively genotyped 163 treated PsA patients. Firstly, we observed a significant difference in the expression level between Responder and non-Responder patients, of 4 lncRNAs in the group of PsA patients treated with TNFi and of 3 lncRNAs in the group of patients treated with IL17i. Then, we confirmed a significant decrease of MEG3 expression in non-Responder patients compared to Responders, also considering separately the single groups of patients treated with TNFi and IL17i. In addition, our results seem to highlight a potential dose-dependent effect of rs941576 (MEG3) variant allele on Disease Activity Index. Our study suggests a possible role of the lncRNA MEG3 in the treatment response to biological drugs.

LncRNA MEG3 Restrains Hepatic Lipogenesis via the FOXO1 Signaling Pathway in HepG2 Cells.

Nonalcoholic fatty liver disease (NAFLD) become a main public health concern, and is characterized by lipid accumulation in the hepatocytes. We found that overexpression of lncRNA MEG3 significantly reduced the expression of FOXO1, ACC1, and FAS, and subsequently decreased the lipid accumulation in HepG2 cells. Moreover, inhibition of lncRNA MEG3 could increase the lipid accumulation and the mRNA and protein levels of FOXO1, ACC1, and FAS. Further study showed that lncRNA MEG3 regulates the lipogenesis process by inhibiting the entry of FOXO1 into the nucleus translocation. Our study demonstrated that lncRNA MEG3 regulates de novo lipogenesis by decreasing the expression and nucleus translocation of FOXO1 in HepG2 cells, suggesting that lncRNA MEG3 could be a promising therapeutic target in lipid metabolic disorders.

The Genetic Variants of Long Noncoding RNA MEG3 and Its Association to the Clinical Features of Diabetic Retinopathy.

PURPOSE: This study aimed to investigate the potential correlation between the single-nucleotide polymorphism (SNP) of maternally expressed gene 3 (MEG3) and the clinical manifestations of diabetic retinopathy (DR). METHODS: Five loci of MEG3 SNPs including rs4081134 (G/A), rs10144253 (T/C), rs7158663 (G/A), rs3087918 (T/G) and rs11160608 (A/C) were genotyped by TaqMan allelic discrimination in 457 non-DR patients and 280 DR individuals. RESULTS: The distribution frequency of MEG3 SNP rs7158663 GA (AOR: 0.683, 95% CI: 0.478-0.975, p = 0.036) and MEG3 SNP rs7158663 GA + AA (AOR: 0.686, 95% CI: 0.487-0.968, p = 0.032) were significantly lower in the DR group. And the MEG3 SNP rs7158663 GA + AA (AOR: 0.610, 95% CI: 0.377-0.985, p = 0.043) demonstrated a significantly lower distribution frequency in the male DR group. Besides, the DR patients with MEG3 SNP rs7158663 GA + AA genotype showed a significantly lower HbA1c level than the DR patients with MEG3 SNP rs7158663 GG genotype (7.29 ± 1.23 versus 7.74 ± 1.49, p = 0.013). Moreover, in the analysis using data from gene expression data series database, a higher MEG3 level was significantly correlated to a lower miR-182 level in the database (p = 0.0114). CONCLUSIONS: In this study, the distribution frequency of MEG3 SNP rs7158663 GA + AA genotype was lower in DR, while the DR would develop under lower HbA1c level in DM patients with this MEG3 SNP variant.

lncRNA Biomarkers of Glioblastoma Multiforme.

Long noncoding RNAs (lncRNAs) are RNA molecules of 200 nucleotides or more in length that are not translated into proteins. Their expression is tissue-specific, with the vast majority involved in the regulation of cellular processes and functions. Many human diseases, including cancer, have been shown to be associated with deregulated lncRNAs, rendering them potential therapeutic targets and biomarkers for differential diagnosis. The expression of lncRNAs in the nervous system varies in different cell types, implicated in mechanisms of neurons and glia, with effects on the development and functioning of the brain. Reports have also shown a link between changes in lncRNA molecules and the etiopathogenesis of brain neoplasia, including glioblastoma multiforme (GBM). GBM is an aggressive variant of brain cancer with an unfavourable prognosis and a median survival of 14-16 months. It is considered a brain-specific disease with the highly invasive malignant cells spreading throughout the neural tissue, impeding the complete resection, and leading to post-surgery recurrences, which are the prime cause of mortality. The early diagnosis of GBM could improve the treatment and extend survival, with the lncRNA profiling of biological fluids promising the detection of neoplastic changes at their initial stages and more effective therapeutic interventions. This review presents a systematic overview of GBM-associated deregulation of lncRNAs with a focus on lncRNA fingerprints in patients' blood.

Control of endothelial cell function and arteriogenesis by MEG3:EZH2 epigenetic regulation of integrin expression.

Epigenetic processes involving long non-coding RNAs regulate endothelial gene expression. However, the underlying regulatory mechanisms causing endothelial dysfunction remain to be elucidated. Enhancer of zeste homolog 2 (EZH2) is an important rheostat of histone H3K27 trimethylation (H3K27me3) that represses endothelial targets, but EZH2 RNA binding capacity and EZH2:RNA functional interactions have not been explored in post-ischemic angiogenesis. We used formaldehyde/UV-assisted crosslinking ligation and sequencing of hybrids and identified a new role for maternally expressed gene 3 (MEG3). MEG3 formed the predominant RNA:RNA hybrid structures in endothelial cells. Moreover, MEG3:EZH2 assists recruitment onto chromatin. By EZH2-chromatin immunoprecipitation, following MEG3 depletion, we demonstrated that MEG3 controls recruitment of EZH2/H3K27me3 onto integrin subunit alpha4 (ITGA4) promoter. Both MEG3 knockdown or EZH2 inhibition (A-395) promoted ITGA4 expression and improved endothelial cell migration and adhesion to fibronectin in vitro. The A-395 inhibitor re-directed MEG3-assisted chromatin remodeling, offering a direct therapeutic benefit by increasing endothelial function and resilience. This approach subsequently increased the expression of ITGA4 in arterioles following ischemic injury in mice, thus promoting arteriogenesis. Our findings show a context-specific role for MEG3 in guiding EZH2 to repress ITGA4. Novel therapeutic strategies could antagonize MEG3:EZH2 interaction for pre-clinical studies.

Alteration in the expression of long non-coding RNAs in the circulation of migraineurs.

BACKGROUND: Current studies have shown emerging roles of lncRNAs in the pathobiology of neuropathic pain and migraine. METHODS: We have chosen five lncRNAs, namely, PVT1, DSCAM-AS, MEG3, LINC-ROR, and SPRY4-IT1 for assessment of their expression in the circulation of migraineurs. RESULTS: Expressions of PVT1 and MEG3 were higher in total migraineurs and both subgroups compared with controls (P < 0.0001). Meanwhile, expression of both lncRNA was higher in migraineurs with aura versus migraineurs without aura (P value < 0.0001 and = 0.01, respectively). Expression of DSCAM-AS1 was not different between any groups of patients compared with controls. Expression of LINC-ROR was elevated in total patients and patients with aura compared with controls (P value = 0.0002 and < 0.0001, respectively). It was also over-expressed in migraineurs with aura vs. migraineurs without aura (P = 0.01). Finally, expression of SPRY4-IT1 was higher in total patients and patients without aura compared with migraine-free persons (P values < 0.0001). Expressions of five mentioned lncRNAs were correlated in almost all study groups. In patients without aura, correlations were significant only for two pairs (SPRY4-IT1/PVT1 and SPRY4-IT1/DSCAM-AS1). PVT1 and MEG3 had the appropriate AUC, sensitivity and specificity values for separation of total migraineurs and both groups of patients from controls. The highest AUC value was reported for PVT1 in separation of migraineurs with aura from healthy controls (AUC = 0.98). CONCLUSION: Cumulatively, our study shows evidence for deregulation of lncRNAs in migraineurs.

MEG3 shuttled by exosomes released from human bone marrow mesenchymal stem cells promotes TP53 stability to regulate MCM5 transcription in keloid fibroblasts.

BACKGROUND: Despite the interest in mesenchymal stem cells (MSC), their potential to treat abnormal scarring, especially keloids, is yet to be described. The present study aimed to investigate the therapeutic potential of exosomes derived from human bone marrow MSCs (hBMSC-Exos) in alleviating keloid formation. METHODS: Exosomes were isolated from hBMSC, and keloid fibroblasts (KFs) were treated with hBMSC-Exos. Cell counting kit-8, wound healing, transwell invasion, immunofluorescence, and western blot assays were conducted to study the malignant phenotype of KFs. Mice were induced with keloids and treated with hBMSC-Exos. The effect of hBMSC-Exos on keloid formation in vivo was evaluated by hematoxylin and eosin staining, Masson staining, immunohistochemistry, and western blotting. The GSE182192 dataset was screened for differentially expressed long non-coding RNA during keloid formation. Next, maternally expressed gene 3 (MEG3) was knocked down in hBMSC to obtain hBMSC-Exossh-MEG3. The molecular mechanism of MEG3 was investigated by bioinformatic screening, and the relationship between MEG3 and TP53 or MCM5 was verified. RESULTS: hBMSC-Exos inhibited the malignant proliferation, migration, and invasion of KFs at same time as promoting their apoptosis, Moreover, hBMSC-Exos reduced the expression of fibrosis- and collagen-related proteins in the cells and the formation of keloids caused by KFs. The reduction in MEG3 enrichment in hBMSC-Exos weakened the inhibitory effect of hBMSC-Exos on KF activity. hBMSC-Exos delivered MEG3 to promote MCM5 transcription by TP53 in KFs. Overexpression of MCM5 in KFs reversed the effects of hBMSC-Exossh-MEG3, leading to reduced KF activity. CONCLUSIONS: hBMSC-Exos delivered MEG3 to promote the protein stability of TP53, thereby activating MCM5 and promoting KF activity.

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.

Imaging and Assay of the Dynamics of Cytotoxic Huntingtin (HTT) Protein Aggregates Regulated by lncRNAs.

Huntington's disease (HD) pathogenesis involves deregulation of coding and noncoding RNA transcripts of which the involvement of long noncoding RNAs (lncRNA) has been realized recently. Of these, Meg3, Neat1, and Xist showed a consistent and significant increase in HD cell and animal models. In the present study, we formulate a methodology to visualize and quantify intracellular aggregates formed by mutant HTT protein. This method employs the use of both confocal laser scanning and super resolution (N-SIM) microscopy to accurately estimate aggregate numbers. Further, to determine the role of two lncRNAs Meg3 and Neat1 in the formation of aggregates of mutant HTT, we used commercially available siRNAs against Meg3 and Neat1 for transiently knocking them down in mouse Neuro2a and human SHSY5Y cells. Co-transfection of 83Q-DsRed and siRNA specific for Neat1 or Meg3 resulted in decreased intracellular aggregates of 83Q-DsRed in both the cell lines. We have established a quantitative method to estimate and directly or indirectly modulate the formation of mutant HTT aggregates.