Long Non-coding RNA MEG3 Induces Renal Cell Carcinoma Cells Apoptosis by Activating the Mitochondrial Pathway

Summary： This study aimed to examine the effect of long non-coding RNA （LncRNA） MEG3 on the biological behaviors of renal cell carcinoma （RCC） cells 786-0 and the possible mechanism. MEG3 expression levels were detected by RT-qPCR in Rmaor tissues and adjacent non-tumor tissues from 29 RCC patients and in RCC lines 786-0 and SN12 and human embryonic kidney cell line 293T. Plasmids GV144-MEG3 （MEG3 overexpression plasmid） and GV144 （control plasmid） were stably transfected into 786-0 cells by using lipofectamine 2000. Cell viabilities were determined by MTT, cell apoptosis rates by flow cytometry following PE Annexin V and 7AAD staining, apoptosis-related protein expressions by Western blotting, and Bcl-2 mRNA by RT-qPCR in the transfected cells. The results showed that MEG3 was evidently downregulated in RCC tissues （P〈0.05） and RCC cell lines （P〈0.05）. The viabilities of 786-0 cells were decreased significantly after transfection with GV144-MEG3 for over 24 h （P〈0.05）. Consistently, the apoptosis rate was significantly increased in 786-0 cells transfected with GV144-MEG3 for 48 h （P〈0.05）. Furthermore, overexpression of MEG3 could reduce the expression of Bcl-2 and procaspase-9 proteins, enhance the expression of cleaved caspase-9 protein, and promote the release of cytochrome c protein to cytoplasm （P〈0.05）. Additionally, Bcl-2 mRNA level was declined by MEG3 overexpression （P〈0.05）. It was concluded that MEG3 induces the apoptosis of RCC cells possibly by activating the mitochondrial pathway.

Decreased expression of the long non-coding RNA HOXD-AS2 promotes gastric cancer progression by targeting HOXD8 and activating PI3K/Akt signaling pathway

BACKGROUND Long non-coding RNAs(lncRNAs) have been shown to be associated with many tumors. However, the specific mechanism of lncRNAs in the occurrence and development of gastric cancer(GC) has not been fully elucidated.AIM To explore the expression level and molecular mechanism of HOXD-AS2 in GC tissues and cells, and analyze its significance in the prognosis of GC.METHODS Real-time quantitative PCR was used to detect the expression of HOXD-AS2 in 79 pairs of GC tissues and five cell lines. The pc HOXD-AS2 plasmid vector was constructed and transfected into SGC-7901 and SNU-1 GC cells. Matrigel Transwell and wound healing assays were used to confirm the effect of HOXDAS2 on invasion and migration of GC cells. Cell counting kit-8 assay and flow cytometry were used to verify the effect of HOXD-AS2 on the proliferation, cell cycle, and apoptosis of GC cells. The relevant regulatory mechanism between HOXD-AS2 and HOXD8 and PI3K/Akt signaling pathway was verified by Western blot analysis.RESULTS The low expression of lncRNA HOXD-AS2 was associated with lymph node metastasis and tumor-node-metastasis stage in GC. In vitro functional experiments demonstrated that overexpression of HOXD-AS2 inhibited GC cell progression. Mechanistic studies revealed that HOXD-AS2 regulated the expression of its nearby gene HOXD8 and inhibited the activity of the PI3K/Akt signaling pathway.CONCLUSION These results indicate that downregulation of HOXD-AS2 significantly promotes the progression of GC cells by regulating HOXD8 expression and activating the PI3K/Akt signaling pathway. HOXD-AS2 may be a novel diagnostic biomarker and effective therapeutic target for GC.

Basic Study Long non-coding RNA TP73-AS1 promotes pancreatic cancer growth and metastasis through miRNA-128-3p/GOLM1 axis

BACKGROUND Previous studies have suggested that long non-coding RNAs(lncRNA)TP73-AS1 is significantly upregulated in several cancers.However,the biological role and clinical significance of TP73-AS1 in pancreatic cancer(PC)remain unclear.AIM To investigate the role of TP73-AS1 in the growth and metastasis of PC.METHODS The expression of lncRNA TP73-AS1,miR-128-3p,and GOLM1 in PC tissues and cells was detected by quantitative real-time polymerase chain reaction.The bioinformatics prediction software ENCORI was used to predict the putative binding sites of miR-128-3p.The regulatory roles of TP73-AS1 and miR-128-3p in cell proliferation,migration,and invasion abilities were verified by Cell Counting Kit-8,wound-healing,and transwell assays,as well as flow cytometry and Western blot analysis.The interactions among TP73-AS1,miR-128-3p,and GOLM1 were explored by bioinformatics prediction,luciferase assay,and Western blot.RESULTS The expression of TP73-AS1 and miRNA-128-3p was dysregulated in PC tissues and cells.High TP73-AS1 expression was correlated with a poor prognosis.TP73-AS1 silencing inhibited PC cell proliferation,migration,and invasion in vitro as well as suppressed tumor growth in vivo.Mechanistically,TP73-AS1 was validated to promote PC progression through GOLM1 upregulation by competitively binding to miR-128-3p.CONCLUSION Our results demonstrated that TP73-AS1 promotes PC progression by regulating the miR-128-3p/GOLM1 axis,which might provide a potential treatment strategy for patients with PC.

Long non-coding RNA highly up-regulated in liver cancer promotes exosome secretion

BACKGROUND Highly upregulated in liver cancer (HULC) is a long non-coding RNA (lncRNA) which has recently been identified as a key regulator in hepatocellular carcinoma (HCC) progression. However, its role in the secretion of exosomes from HCC cells remains unknown. AIM To explore the mechanism by which HULC promotes the secretion of exosomes from HCC cells. METHODS Serum and liver tissue samples were collected from 30 patients with HCC who had not received chemotherapy, radiotherapy, or immunotherapy before surgery. HULC expression in serum exosomes and liver cancer tissues of patients was measured, and compared with the data obtained from healthy controls and tumor adjacent tissues. The effect of HULC upregulation in HCC cell lines and the relationship between HULC and other RNAs were studied using qPCR and dualluciferase reporter assays. Nanoparticle tracking analysis was performed to detect the quantity of exosomes.RESULTS HULC expression in serum exosomes of patients with HCC was higher than that in serum exosomes of healthy controls, and HULC levels were higher in liver cancer tissues than in tumor adjacent tissues. The expression of HULC in serum exosomes and liver cancer tissues correlated with the tumor-node-metastasis (TNM) classification, and HULC expression in tissues correlated with that in serum exosomes. Upregulation of HULC promoted HCC cell growth and invasion and repressed apoptosis. Notably, it also facilitated the secretion of exosomes from HCC cells. Moreover, qPCR assays showed that HULC repressed microRNA-372-3p (miR-372-3p) expression. We also identified Rab11a as a downstream target of miR-372-3p. Dual-luciferase reporter assays suggested that miR-372-3p could directly bind both HULC and Rab11a. CONCLUSION Our findings illustrate the importance of the HULC/miR-372-3p/Rab11a axis in HCC and provide new insights into the molecular mechanism regulating the secretion of exosomes from HCC cells.

Expressions of Long Non-Coding RNAs in Carcinogenesis of Cervix: A Review

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides mostly transcribed by RNA which do not encode proteins. Previously, lncRNAs were considered transcriptional byproducts called “junk DNA” with no biological functions. There are many studies conducted on lncRNAs showing they are actively involved in regulation of epigenetic, transcriptional, and post-transcriptional events. Expressions of lncRNAs are more different in many malignant tumors than in benign tumors and normal tissue. Aberration of lncRNAs is responsible to promote or suppress tumorigenesis and cancer progression. Under different circumstances, lncRNAs exhibit their roles in carcinogenesis such as MALAT1 is responsible for intervening mRNA instability, HOTAIR, MALAT1, ANRIL, PVT1 links with miRNA and histonemodifying complexes, MEG3 associates with miRNA, CCAT2, MEG3, GAS5, UCA1 allies with c-Myc or P53 causing suppression of tumor or oncogenesis. Abnormal expressions of lncRNAs are noticed in gynecological cancers, such as cervical cancer, ovarian cancer, and endometrial cancer. Identification of cervical cancer associated lncRNAs is necessary to understand the molecular biogenesis of cancers. In this review, we summarized the foundation and function of the lncRNAs in terms of tumor progression, invasion, prognosis, apoptosis, metastasis, and chemo-resistance. This review will provide references to determine the clinical applications of lncRNAs as ideal diagnostic biomarkers or therapeutic targets in cervical cancers.

Danhongqing formula alleviates cholestatic liver fibrosis by downregulating long non-coding RNA H19 derived from cholangiocytes and inhibiting hepatic stellate cell activation

Objective:This study explores the mechanism of action of Danhongqing formula(DHQ),a compoundbased Chinese medicine formula,in the treatment of cholestatic liver fibrosis.Methods:In vivo experiments were conducted using 8-week-old multidrug resistance protein 2 knockout(Mdr2-/-)mice as an animal model of cholestatic liver fibrosis.DHQ was administered orally for 8 weeks,and its impact on cholestatic liver fibrosis was evaluated by assessing liver function,liver histopathology,and the expression of liver fibrosis-related proteins.Real-time polymerase chain reaction,Western blot,immunohistochemistry and other methods were used to observe the effects of DHQ on long non-coding RNA H19(H19)and signal transducer and activator of transcription 3(STAT3)phosphorylation in the liver tissue of Mdr2-/-mice.In addition,cholangiocytes and hepatic stellate cells(HSCs)were cultured in vitro to measure the effects of bile acids on cholangiocyte injury and H19 expression.Cholangiocytes overexpressing H19 were constructed,and a conditioned medium containing H19 was collected to measure its effects on STAT3 protein expression and cell activation.The intervention effect of DHQ on these processes was also investigated.HSCs overexpressing H19 were constructed to measure the impact of H19 on cell activation and assess the intervention effect of DHQ.Results:DHQ alleviated liver injury,ductular reaction,and fibrosis in Mdr2-/-mice,and inhibited H19expression,STAT3 expression and STAT3 phosphorylation.This formula also reduced hydrophobic bile acid-induced cholangiocyte injury and the upregulation of H19,inhibited the activation of HSCs induced by cholangiocyte-derived conditioned medium,and decreased the expression of activation markers in HSCs.The overexpression of H19 in a human HSC line confirmed that H19 promoted STAT3 phosphorylation and HSC activation,and DHQ was able to successfully inhibit these effects.Conclusion:DHQ effectively alleviated spontaneous cholestatic liver fibrosis in Mdr2-/-mice by inhibiting H19 upregulation in cholangiocytes and preventing the inhibition of STAT3 phosphorylation in HSC,thereby suppressing cell activation.

The long non-coding RNA DANA2 positively regulates drought tolerance by recruitingERF84 to promote JMJ29-mediated histone demethylation

Tens of thousands of long non-coding RNAs have been uncovered in plants,but few of them have been comprehensively studied for their biological function and molecular mechanism of their mode of action.Here,we show that the Arabidopsis long non-coding RNA DANA2 interacts with an AP2/ERF transcription factor ERF84 in the cell nucleus and then affects the transcription of JMJ29 that encodes a Jumonji C domain-containing histone H3K9 demethylase.Both RNA sequencing(RNA-seq)and genetic analyses demonstrate that DANA2 positively regulates drought stress responses through JMJ29.JMJ29 positively regulates the expression of ERF15 and GOLS2 by modulation of H3K9me2 demethylation.Accordingly,mutation of JMJ29 causes decreased ERF15 and GOLS2 expression,resulting in impaired drought tolerance,in agreement with drought-sensitive phenotypes of dana2 and erf84 mutants.Taken together,these results demonstrate that DANA2 is a positive regulator of drought response and works jointly with the transcriptional activator ERF84 to modulate JMJ29 expression in plant response to drought.

Upregulation of MEG3 inhibits neuroblastoma progression via decreasing proliferation and promoting apoptosis

Background:We have shown that downregulation of materally expressed gene 3(MEG3)promoted autophagy and epithelial-mesenchymal transition to promote neuroblastoma(NB)progression.In present study,we aim to further discover the role of MEG3 in NB.Methods:Expression levels of MEG3 in stabled transfected cells were detected by qPCR.Flow cytometry was used to examine the effects of MEG3 overexpression on apoptosis and cell cycle.Moreover,tumor stemness was detected by tumor sphere formation assay.Results:QPCR showed that MEG3 was successfully overexpressed in SK-N-BE(2)C and SK-N-AS cells.CCK8 indicated MEG3 reduced cell proliferation in two NB cells.Flow cytometry revealed that MEG3 promoted apoptosis and caused G0/G1 arrest.Using chromatin isolation by RNA purification(ChIRP)and tumor sphere formation assays,we revealed that upregulation of MEG3 decreased tumor stemness by decreasing Nestin transcription.Conclusions:Overall,present study confirmed an anti-cancer role of MEG3 in NB,demonstrated that MEG3 could be a potential therapeutic target of NB.

Expression Profile and Function Analysis of Long Non-coding RNAs in the Infection of Coxsackievirus B3

The roles of lnc RNAs in the infection of enteroviruses have been barely demonstrated. In this study, we used coxsackievirus B3(CVB3), a typical enterovirus, as a model to investigate the expression profiles and functional roles of lnc RNAs in enterovirus infection. We profiled lnc RNAs and m RNA expression in CVB3-infected He La cells by lnc RNA-m RNA integrated microarrays. As a result, 700 differentially expressed lnc RNAs(431 up-regulated and 269 down-regulated) and665 differentially expressed m RNAs(299 up-regulated and 366 down-regulated) were identified in CVB3 infection. Then we performed lnc RNA-m RNA integrated pathway analysis to identify potential functional impacts of the differentially expressed m RNAs, in which lnc RNA-m RNA correlation network was built. According to lnc RNA-m RNA correlation, we found that XLOC-001188, an lnc RNA down-regulated in CVB3 infection, was negatively correlated with NFAT5 m RNA,an anti-CVB3 gene reported previously. This interaction was supported by q PCR detection following si RNA-mediated knockdown of XLOC-001188, which showed an increase of NFAT5 m RNA and a reduction of CVB3 genomic RNA. In addition, we observed that four most significantly altered lnc RNAs, SNHG11, RP11-145 F16.2, RP11-1023 L17.1 and RP11-1021 N1.2 share several common correlated genes critical for CVB3 infection, such as BRE and IRF2 BP1. In all, our studies reveal the alteration of lnc RNA expression in CVB3 infection and its potential influence on CVB3 replication,providing useful information for future studies of enterovirus infection.

Silencing novel long non-coding RNA FKBP9P1 represses malignant progression and inhibits PI3K/AKT signaling of head and neck squamous cell carcinoma in vitro

Background:Long non-coding RNAs(lncRNAs)play key roles in human cancers.In our previous study,we demonstrated that lncRNA FKBP prolyl isomerase 9 pseudogene 1(FKBP9P1)was highly expressed in head and neck squamous cell cancer(HNSCC)tissues.However,its functional significance remains poorly understood.In the present study,we identify the role and potential molecular biologic mechanisms of FKBP9P1 in HNSCC.Methods:Quantitative real-time polymerase chain reaction was used to detect the expression of FKBP9P1 in HNSCC tissues,matched adjacent normal tissues,human HNSCC cells(FaDu,Cal-27,SCC4,and SCC9),and human immortalized keratinocytes cell HaCaT(normal control).Cal-27 and SCC9 cells were transfected with sh-FKBP9P1-1,sh-FKBP9P1-2,and normal control(sh-NC)lentivirus.Cell counting kit-8 assay,colony formation assay,wound healing assay,and trans-well assay were used to explore the biologic function of FKBP9P1 in HNSCC cells.Furthermore,western blotting was used to determine the mechanism of FKBP9P1 in HNSCC progression.Chi-squared test was performed to assess the clinical significance among FKBP9P1 high-expression and low-expression groups.Survival analyses were performed using the Kaplan-Meier method and assessed using the log-rank test.The comparison between two groups was analyzed by Student t test,and comparisons among multiple samples were performed by one-way analysis of variance and a Bonferroni post hoc test.Results:FKBP9P1 expression was significantly up-regulated in HNSCC tissues(tumor vs.normal,1.914 vs.0.957,t=7.746,P<0.001)and cell lines(P<0.01 in all HNSCC cell lines).Besides,the median FKBP9P1 expression of HNSCC tissues(1.677)was considered as the threshold.High FKBP9P1 level was correlated with advanced T stage(P=0.022),advanced N stage(P=0.036),advanced clinical stage(P=0.018),and poor prognosis of HNSCC patients(overall survival,P=0.002 and disease-free survival,P<0.001).Knockdown of FKBP9P1 led to marked repression in proliferation,migration,and invasion of HNSCC cells in vitro(P all<0.01).Mechanistically,silencing FKBP9P1 was observed to restrain the PI3K/AKT signaling pathway.Conclusions:Silencing lncRNA FKBP9P1 represses HNSCC progression and inhibits PI3K/AKT(phosphatidylinositol 3 kinase/AKT Serine/Threonine Kinase)signaling in vitro.Therefore,FKBP9P1 could be a potential new target for the diagnosis and treatment of HNSCC patients.

Long Non-coding RNAs Expression Profile in HepG2 Cells Reveals the Potential Role of Long Non-coding RNAs in the Cholesterol Metabolism

Background：Green tea has been shown to improve cholesterol metabolism in animal studies,but the molecular mechanisms underlying this function have not been fully understood.Long non-coding RNAs （lncRNAs） have recently emerged as a major class of regulatory molecules involved in a broad range of biological processes and complex diseases.Our aim was to identify important lncRNAs that might play an important role in contributing to the benefits of epigallocatechin-3-gallate （EGCG） on cholesterol metabolism.Methods：Microarrays was used to reveal the lncRNA and mRNA profiles in green tea polyphenol（-）-epigallocatechin gallate in cultured human liver （HepG2） hepatocytes treated with EGCG and bioinformatic analyses of the predicted target genes were performed to identify lncRNA-mRNA targeting relationships.RNA interference was used to investigate the role of lncRNAs in cholesterol metabolism.Results：The expression levels of 15 genes related to cholesterol metabolism and 285 lncRNAs were changed by EGCG treatment.Bioinformatic analysis found five matched lncRNA-mRNA pairs for five differentially expressed lncRNAs and four differentially expressed mRNA.In particular,the lncRNA4 T102202 and its potential targets mRNA-3-hydroxy-3-methylglutaryl coenzyme A reductase （HMGCR） were identified.Using a real-time polymerase chain reaction technique,we confirmed that EGCG down-regulated mRNA expression level of the HMGCR and up-regulated expression ofAT102202.After AT102202 knockdown in HepG2,we observed that the level of HMGCR expression was significantly increased relative to the scrambled small interfering RNA control （P 〈 0.05）.Conclusions：Our results indicated that EGCG improved cholesterol metabolism and meanwhile changed the lncRNAs expression profile in HepG2 cells.LncRNAs may play an important role in the cholesterol metabolism.

LncRNA AFAP1-AS1/miR-27b-3p/VEGF-C axis modulates stemness characteristics in cervical cancer cells

Background:Long non-coding RNA(lncRNA)actin filament-associated protein 1 antisense RNA 1(AFAP1-AS1)functions as a competing endogenous RNA to regulate target genes expression by sponging microRNAs(miRs)to play cancer-promoting roles in cancer stem cells.However,the regulatory mechanism of AFAP1-AS1 in cervical cancer(CC)stem cells is unknown.The present study aimed to provide a new therapeutic target for the clinical treatment of CC.Methods:Hyaluronic acid receptor cluster of differentiation 44 variant exon 6(CD44v6)(+)CC cells were isolated by flow cytometry(FCM).Small interfering RNAs of AFAP1-AS1(siAFAP1-AS1)were transfected into the(CD44v6)(+)cells.The levels of AFAP1-AS1 were measured by quantitative real-time PCR(qRT-PCR).Sphere formation assay,cell cycle analysis,and Western blotting were used to detect the effect of siAFAP1-AS1.RNA pull-down and luciferase reporter assay were used to verify the relationship between miR-27b-3p and AFAP1-AS1 or vascular endothelial growth factor(VEGF)-C.Results:CD44v6(+)CCcells had remarkable stemness and a high level ofAFAP1-AS1.However,AFAP1-AS1knockdownwithsiAFAP1-AS1suppressed the cell cycle transitionofG(1)/S phase and inhibited self-renewal ofCD44v6(+)CCcells,the levels of the stemnessmarkers octamer-binding transcription factor 4(OCT4),osteopontin(OPN),and cluster of differentiation 133(CD133),and the epithelialmesenchymal transition(EMT)-related proteins Twist1,matrix metalloprotease(MMP)-9,and VEGF-C.In the mechanism study,miR-27b-3p/VEGF-C signaling was demonstrated to be a key downstream of AFAP1-AS1 in the CD44v6(+)CC cells.Conclusions:LncRNA AFAP1-AS1 knockdown inhibits the CC cell stemness by upregulating miR-27b-3p to suppress VEGF-C.

Macrophage migration inhibitory factor protects bone marrow mesenchymal stem cells from hypoxia/ischemia-induced apoptosis by regulating lncRNA

Objective:This research was performed to explore the effect of macrophage migration inhibitory factor(MIF)on the apoptosis of bone marrow mesenchymal stem cells(BMSCs)in ischemia and hypoxia environments.Methods:The cell viability of BMSCs incubated under hypoxia/ischemia(H/I)conditions with or without pretreatment with MIF or triglycidyl isocyanurate(TGIC)was detected using cell counting kit-8(CCK-8)analysis.Plasmids containing long noncoding RNA(lncRNA)maternally expressed gene 3(MEG3)orβ-catenin small interfering RNA(siRNA)were used to overexpress or downregulate the corresponding gene,and the p53 signaling pathway was activated by pretreatment with TGIC.The influences of MIF,overexpression of lncRNA MEG3,activation of the p53 signaling pathway,and silencing ofβ-catenin on H/I-induced apoptosis of BMSCs were revealed by western blotting,flow cytometry,and terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick-end labeling(TUNEL)staining.Results:From the results of CCK-8 assay,western blotting,and flow cytometry,pretreatment with MIF significantly decreased the H/I-induced apoptosis of BMSCs.This effect was inhibited when lncRNA MEG3 was overexpressed by plasmids containing MEG3.The p53 signaling pathway was activated by TGIC,andβ-catenin was silenced by siRNA.From western blot results,the expression levels ofβ-catenin in the nucleus and phosphorylated p53(p-p53)were downregulated and upregulated,respectively,when the lncRNA MEG3 was overexpressed.Through flow cytometry,MIF was also shown to significantly alleviate the increased reactive oxygen species(ROS)level of BMSCs caused by H/I.Conclusions:In summary,we conclude that MIF protected BMSCs from H/I-induced apoptosis by downregulating the lncRNA MEG3/p53 signaling pathway,activating the Wnt/β-catenin signaling pathway,and decreasing ROS levels.