lncRNA Metastasis-associated Lung Adenocarcinoma Transcript 1 Research Articles

LncRNA MALAT1 Enhances ox-LDL-Induced Autophagy through the SIRT1/MAPK/NF-κB Pathway in Macrophages.

Atherosclerosis is the main cause of cardiovascular and cerebrovascular diseases. In advanced atherosclerotic plaque, macrophage apoptosis coupled with inflammatory cytokine secretion promotes the formation of necrotic cores. It has also been demonstrated that the long-noncoding Ribonucleic Acid (lnc RNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), with its potent function on gene transcription modulation, maintains oxidized low-density lipoprotein (ox-LDL)- induced macrophage autophagy (i.e., helps with cholesterol efflux). It also showed that MALAT1 activated Sirtuin 1 (SIRT1), which subsequently inhibited the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathways. ox-LDL has been used to incubate human myeloid leukemia mononuclear cells (THP-1)-derived macrophages to establish an in vitro foam cell model. Quantitative reverse-transcription polymerase chain reaction and Western blot analyses confirmed the increased expression level of MALAT1 and the autophagy-related protein Microtubuleassociated protein light chain 3 (LC-3), beclin-1. The small interfering RNA study showed a significant decrease in autophagy activity and an increase in apoptotic rate when knocking down MALAT1. Further study demonstrated that MALAT1 inhibited the expression of MAPK and NF-κB (p65) by upregulating SIRT1.

Long Non-Coding RNA (lncRNA) Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Promotes Cell Proliferation and Migration by Regulating miR-143-3p and MAGE Family Member A9 (MAGEA9) in Oral Squamous Cell Carcinoma

BackgroundlncRNA MALAT1 is one of the most widely studied lncRNAs associated with various human cancers. The present study explored the functions and potential regulatory mechanisms of MALAT1 in oral squamous cell carcinoma (OSCC).Material/MethodsWe assessed levels of MALAT1, miR-143-3p, and MAGEA9 expression in OSCC tissues and cell lines by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assay. Proliferation and migration of CAL-27 cells were detected via CCK-8 and transwell assays, respectively. To study the relationships among MALAT1, miR-143-3p, and MAGEA9, we performed dual-luciferase assay and assessed the results using Spearman correlation analysis.ResultsQRT-PCR results showed that MALAT1 and MAGEA9 were expressed at higher levels and miR-143-3p was expressed at lower levels in OSCC tissues. Dramatic suppression of cell proliferation and migration abilities were caused by MALAT1 knockdown or miR-143-3p overexpression in CAL-27 cells. MALAT1 directly interacted with and negatively regulated miR-143-3p. Moreover, MAGEA9 was validated as a miR-143-3p target gene and was found to be negatively regulated by it. MALAT1 knockdown suppressed MAGEA9 protein expression and had the same effect as MAGEA9 knockdown. Additionally, MAGEA9 knockdown inhibited CAL-27 cell proliferation and migration abilities. Finally, in OSCC tissues, MALAT1 and miR-143-3p expression were negatively correlated and MALAT1 was positively correlated with MAGEA9 expression, while an inverse correlation between MAGEA9 and miR-143-3p expression was observed.ConclusionsTaken together, our results suggest that MALAT1 functions as a competing endogenous RNA (ceRNA) in promoting OSCC cell proliferation and migration abilities through the miR-143-3p/MAGEA9 axis, thus providing new therapeutic targets for treatment of OSCC.

LncRNA MALAT1 promotes cell proliferation and invasion by regulating the miR-101/EZH2 axis in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor of the oral cavity. Emerging evidence indicates that long non-coding (lnc)RNAs play a key role in the cellular processes of tumor cells, including glycolysis, growth and movement. Here, the purpose of this study was to explore the biological functions and potential mechanism of lncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in OSCC. OSCC tissues and adjacent matched paraneoplastic normal tissues were collected from 20 OSCC patients. The expression of MALAT1 and miR-101 in OSCC tissues and cell lines (HSC3, SCC9, SCC15 and SCC25) were determined by real-time-polymerase chain reaction (qPCR). Caspase-3, xaspase-8 and EZH2 protein levels were determined by western blot analysis. MALAT1-mediated miRNAs were verified by bioinformatics analysis of StarBase and Luciferase reporter assay. Cell Counting Kit-8 (CCK-8) and Transwell assays were used for investigating MALAT1 effect on cell proliferation and invasion in the OSCC cells. qPCR analysis indicated that MALAT1 expression was obviously increased, and miR-101 was decreased in the OSCC tissues and cell lines. Functional studies revealed that overexpression of MALAT1 promoted OSCC cell proliferation and invasion. Further experiments revealed that miR-101 was a target of MALAT1 and that the miR-101 inhibitor abolished the effect of MALAT1 on OSCC cell proliferation and invasion. Enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) acted as a downstream effecter of MALAT1 in the OSCC cells. Collectively, these findings revealed that upregulation of MALAT1 facilitated OSCC proliferation and invasion by targeting the miR-101/EZH2 axis.

Abstract 3142: Stress regulated role of lncRNA Malat1 in colorectal cancer progression and metastasis

Abstract Background: Colorectal carcinoma (CRC) is the second leading cause of cancer related deaths in the United States. The five-year survival rate of patients diagnosed with distant stages declines to 14%, which is of concern when compared to 90% for localized-stage and 71% for regional stage disease. This necessitates the need for early diagnostic biomarkers, to minimize poor drug response/resistance, recurrence, metastasis and mortality. Disproportionate biochemical stressors increase the risk of developing CRC and its progression by influencing molecular drivers within the coding and noncoding parts of the genome. Thus, understanding the biological mechanism of these stress factors on the molecular drivers of this disease can provide pivotal information pertinent to CRC development and progression. Recently, our laboratory has identified a novel long noncoding RNA (lncRNA) namely, Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), which is highly over-expressed in CRC and is involved in its pathogenesis and is regulated by transcription factor Nuclear Factor of Activated T cell 1 (NFATc1). Methods: Archived human CRC tissues were stained using a recently standardized Z-probe technology. TCGA database of ~600 CRC patients was also analyzed using the bioinformatic approach. CRC cell lines were profiled for MALAT1 expression using RT-PCR. Lentiviral constructs were used to generate stable lncRNA MALAT1 expressing cell lines. CRISPR/Cas9 constructs were used to knockdown lncRNA MALAT1 and NFATc1. Mouse model was used to verify the stress induced expression of MALAT1 and NFATc1. ReCLP (Reversible Cross-Linked Precipitation) and iRAP (invitro RNA Antisense Proteomics) studies are in progress to identify the associated proteins and complexes. Results: RNAScope analysis showed MALAT1 to be highly over-expressed in human CRC tissues. MALAT1 expression increased with stage and negatively correlated with the tumor size. TCGA database analysis confirmed our findings. Multiple NFATc1 binding site were identified by ChIPseq database. Overexpression of transcription factor NFATc1 upregulated lncRNA MALAT1 expression. CRISPR/Cas9 based knockdown of NFATc1 downregulated NFATC1 and lncRNA MALAT1, but vice versa was not true, indicating NFATc1 to be upstream of lncRNA MALAT1. Also, expression of MALAT1, NFATc1 and IL-6 were highly upregulated by biochemical stressor cortisol in mouse colonic tissues. Further studies are in progress for direct association of NFATc1 on MALAT1 promoter and mechanism by which the stress factor regulate NFATc1 expression and hence lncRNA MALAT1 expression. Conclusion: This study helps to understand influence of biochemical stress factors on long noncoding RNA MALAT1 and transcription factor NFATc1 etiology. Early diagnosis of these molecular markers will help in designing novel preventive/therapeutic strategies to reduce CRC progression, metastasis and hence mortality. Citation Format: Kyle Doxtater, Chidi Zacheaus, Radhika Sekhri, Utkarsh K. Mishra, Zachary E. Stiles, Nitish Mishra, Chittibabu Guda, Nadeem Zafar, Mahul Amin, Pradeep Shukla, Murali M. Yallapu, Meena Jaggi, Subhash C. Chauhan, Manish K. Tripathi. Stress regulated role of lncRNA Malat1 in colorectal cancer progression and metastasis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3142.

P1005LONG NONCODING RNAS MAY INTERVENE IN PODOCYTE INJURY AND PROXIMAL TUBULE DYSFUNCTION THROUGH MODULATING MIRNAS EXPRESSION IN EARLY DIABETIC KIDNEY DISEASE OF TYPE 2 DIABETES MELLITUS PATIENTS

Abstract Background and Aims Interactions among multiple molecules and signalling pathways contribute to the pathogenesis and progression of diabetic kidney disease (DKD). Long noncoding RNAs (lncRNAs) play key roles in the pathophysiology of DKD involving actions of microRNAs (miRNAs). The aim of the study was to establish the involvement of selected lncRNAs in the epigenetic mechanisms of podocyte damage and tubular injury in DKD of type 2 diabetes mellitus (DM) patients. The molecular mechanisms of lncRNAs intervention were evaluated in relation to a particular miRNA profile. Method A total of 136 patients with type 2 DM and 25 healthy subjects were enrolled in a cross-sectional case series study and assessed concerning urinary albumin: creatinine ratio (UACR), eGFR, biomarkers of podocyte damage (synaptopodin, podocalyxin) and proximal tubule (PT) dysfunction (Kidney injury molecule-1-KIM-1, N-acetyl-D-glucosaminidase-NAG), urinary lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), nuclear-enriched abundant transcript 1 (NEAT1), myocardial infarction-associated transcript (MIAT), taurine-upregulated gene 1 (TUG1), and urinary miRNA21, 124, 93, 29a (quantified by a real-time PCR System). Results Multivariable regression analysis yielded models in which urinary lncRNA MALAT1 correlated directly with urinary synaptopodin, podocalyxin, KIM-1, NAG, miRNA21, 124, UACR, and negatively with eGFR, miRNA93 and 29a (p<0.0001; R2=0.727); urinary lncRNA NEAT1 correlated directly with synaptopodin, KIM-1, NAG, miRNA21, 124, and negatively with eGFR, miRNA93, and 29a (p<0.0001; R2=0.702); urinary lncRNA MIAT correlated directly with miRNA93 and 29a, and eGFR (p<0.0001; R2=0.671) and negatively with synaptopodin, KIM-1, NAG, UACR, miRNA21, and 124 (p<0.0001; R2=0.654); urinary lncRNA TUG1 correlated directly with eGFR, miRNA93 and 29a, and negatively with synaptopodin, podocalyxin, NAG, miRNA21, and 124 (p<0.0001; R2=0.748). The results provided document upregulated lncRNA MALAT1 and NEAT1, as well as miRNA21 and 124. By contrast, lncRNA MIAT and TUG1, and miRNA93 and 29a were downregulated. Conclusion In patients with type 2 DM lncRNAs exert distinct functions in different cell types, either deleterious or protective, at both glomerular and tubular level. LncRNAs may contribute to DKD through modulating miRNAs expression and activities. This observation holds true independently of albuminuria and DKD stage.

LncRNA MALAT1 modulates cancer stem cell properties of liver cancer cells by regulating YAP1 expression via miR‑375 sponging.

Liver cancer stem cells (CSCs) are functionally defined by their ability to undergo self-renewal, and may contribute to metastasis, recurrence and drug resistance in liver cancer. The long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been implicated in tumor formation and metastasis of liver cancer. However, the exact mechanism by which MALAT1 modulates liver CSC features remains largely unknown. In the present study, the expression level of MALAT1 was elevated in cancer spheroids compared with the corresponding levels noted in parental liver cancer cells, whereas the suppression of MALAT1 resulted in markedly reduced sphere formation and decreased expression of stemness factors in liver cancer cells. Dual-luciferase assay and RNA pull-down assays further indicated an interaction between MALAT1 and microRNA (miR)-375, and identified Yes-associated protein 1 (YAP1) as a direct target of miR-375 in liver cancer cells. In addition, YAP1 expression was correlated with MALAT1 in liver cancer. The reduced expression of YAP1 caused by knockdown of MALAT1 with MALAT1 small interfering RNA (si-MALAT1) could be partially abolished by miR-375 inhibition, suggesting that MALAT1 may regulate YAP1 expression by sponging miR-375. Furthermore, YAP1 overexpression rescued the decrease in CSC features of liver cancer cells caused by si-MALAT1, further supporting that MALAT1-mediated YAP1 signaling was required for the stem-like characteristics of liver CSCs. The present study revealed that MALAT1 may promote CSC properties of liver cancer cells by upregulating YAP1 expression via sponging miR-375. The MALAT1/miR-375/YAP1 axis may serve as a novel target for liver cancer therapy, particularly for the eradication of liver CSCs.

Suppression of long non-coding RNA MALAT1 inhibits survival and metastasis of esophagus cancer cells by sponging miR-1-3p/CORO1C/TPM3 axis.

Esophageal cancer (EC) is a malignancy causing lots of mortality worldwide. Long non-coding RNAs (lncRNAs) are involved in the progression of multiple cancer types. The present study aimed to explore the function and associated mechanisms of lncRNA metastasis-associated lung adenocarcinoma transcript1 (MALAT1) in EC development by focusing on its interaction with miR-1-3p. The levels of MALAT1 and miR-1-3p were investigated in clinical EC specimens. Then, the expression of MALAT1 was knocked down in EC cell lines, and the effects of MALAT1 inhibition on the viability, migration, and invasion, and miR-1-3p/Coronin-1C (CORO1C)/Tropomyosin3 (TPM3) axis in EC cells were detected. The interaction between MALAT1 and miR-1-3p in the progression of EC was further determined by suppressing the expression of miR-1-3p in MALAT1 inhibition cells. The results were further verified with EC xenograft mice model. MALAT1 level was downregulated, while miR-1-3p level was upregulated in EC specimens. The inhibition of MALAT1 suppressed the viability, migration, and invasion in EC cell lines. The changes in phenotypes of EC cells were associated with the upregulation of miR-1-3p level and inhibition of CORO1C/TPM3 activity. Furthermore, the results of dual-luciferase assay showed the direct binding of MALAT1 to the seed sequence of miR-1-3p. The suppressed level of miR-1-3p not only induced the activity of CORO1C/TPM3 signaling, but also upregulated MALAT1 expression, indicating the reciprocal regulation between the two factors. The inhibition of MALAT1 also inhibited tumor growth and epithelial-mesenchymal transition (EMT) in mice model, which was reversed by miR-1-3p inhibition. Collectively, MALAT1 was important to the survival and metastasis of EC cells by sponging miR-1-3p.

Role of Nrf2 in MALAT1/ HIF-1α loop on the regulation of angiogenesis in diabetic foot ulcer

Diabetic non healing wounds often result in significant morbidity and mortality. The number of effective targets to detect these wounds are meagre. Slow lymphangiogenesis is one of the complex processes involved in impaired healing of wounds. Long non coding RNAs (lncRNAs) have been importantly recognized for their role in pathological conditions. Multiple studies highlighting the role of lncRNAs in the regulation of several biological processes and complex diseases. Herein, we investigated the role of lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the progression of diabetic foot ulcer (DFU). We report a significant reduction in the expression of lncRNA MALAT1 in the infected DFU subjects which was positively correlated with the expression of angiogenic factors such as Nrf2, HIF-1α and VEGF. Further, expression of pro-inflammatory markers TNF-α and IL-6 were found to be increased while, the expression of anti-inflammatory marker IL-10 was decreased in infected DFU tissues. Involvement of lncRNA MALAT1 in angiogenesis in EA.hy926 cells was demonstrated by silencing the expression of Nrf2, HIF-1α, and VEGF through interference mediated by MALAT1. In addition, its inflammatory role was demonstrated by decreased expression of TNF-α, IL-6 and not affecting the expression of IL-10. Further, CRISPR-Cas9 knock out of Nrf2 decreased the expression of lncRNA MALAT1, HIF-1α and VEGF which revealed the association of Nrf2 in regulating MALAT1/HIF-1α loop through positive feedback mechanism. Collectively, our results suggested the role of Nrf2 on MALAT1/HIF-1α loop in the regulation of angiogenesis, which could act as a novel target in the treatment of diabetic wounds.

LncRNA MALAT1 promoted high glucose-induced pyroptosis of renal tubular epithelial cell by sponging miR-30c targeting for NLRP3.

Diabetic nephropathy (DN), characterized by the chronic loss of kidney function during diabetes, is a long-term kidney disease that affects millions of populations. However, the etiology of DN remains unclear. DN cell model was established by treating HK-2 cells with high glucose (HG) in vitro. Expression of metastasis-associated lung adenocarcinoma transcript-1 (MALAT1), miR-30c, nucleotide binding and oligomerization domain-like receptor protein 3 (NLRP3), caspase-1, IL-1β, and IL-18 in treated HK-2 cells were tested by quantitative polymerase chain reaction. HK-2 cell pyroptosis was assessed using flow cytometry analysis. Lactate dehydrogenase (LDH) activity was examined with a LDH assay kit. Correlation among MALAT1, miR-30c, and NLRP3 was examined via dual-luciferase reporter assay. Here, we revealed that MALAT1 was upregulated, but miR-30c was downregulated in HG-treated HK-2 cells, leading to upregulation of NLRP3 expression and cell pyroptosis. Knockdown of MALAT1 or overexpression of miR-30c protected HK-2 cells from HG-induced pyroptosis. Meanwhile, we found that MALAT1 promoted NLRP3 expression by sponging miR-30c through dual-luciferase reporter assay. Moreover, the co-transfection of sh-MALAT1 and miR-30c inhibitor could reverse the protective effects of the sh-MALAT1 on the HG-induced pyroptosis. These results confirmed that MALAT1 regulated HK-2 cell pyroptosis by inhibiting miR-30c targeting for NLRP3, contributing to a better understanding of DN pathogenesis and help to find out the effective treatment for DN.

Increased Level of Long Non-Coding RNA MALAT1 is a Common Feature of Amoeboid Invasion.

The ability of cancer cells to adopt various migration modes (the plasticity of cancer cell invasiveness) is a substantive obstacle in the treatment of metastasis, yet still an incompletely understood process. We performed a comparison of publicly available transcriptomic datasets from various cell types undergoing a switch between the mesenchymal and amoeboid migration modes. Strikingly, lncRNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) was one of three genes that were found upregulated in all amoeboid cells analyzed. Accordingly, downregulation of MALAT1 in predominantly amoeboid cell lines A375m2 and A2058 resulted in decrease of active RhoA (Ras homolog family member A) and was accompanied by the amoeboid-mesenchymal transition in A375m2 cells. Moreover, MALAT1 downregulation in amoeboid cells led to increased cell proliferation. Our work is the first to address the role of MALAT1 in MAT/AMT (mesenchymal to amoeboid transition/amoeboid to mesenchymal transition) and suggests that increased MALAT1 expression is a common feature of amoeboid cells.

MicroRNA Binding Site Polymorphisms of the Long-Chain Noncoding RNA MALAT1 are Associated with Risk and Prognosis of Colorectal Cancer in Chinese Han Population

Background: The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) gene's rs664589 locus is located within the binding site of the miRNA hsa-miR-194-5p for its cognate long-chain noncoding RNA (lncRNA) MALAT1. The aim of this study was to investigate the association between the rs664589 single nucleotide polymorphism (SNP) and the risk and prognosis of colorectal cancer (CRC) in the Chinese Han population. Methods: A cohort of 340 patients with CRC who underwent surgical resection and another group of 340 healthy subjects were enrolled in this study and analyzed for their rs664589 genotypes. In addition, quantitative real-time-polymerase chain reaction was used to detect the expression levels of the lncRNA MALAT1 and the hsa-miR-194-5p in cancer tissues and paracancerous normal tissues of CRC patients. Results: The risk of CRC in subjects carrying the G allele at the rs664589 locus in the 3' untranslated region of the MALAT1 gene was 1.81 times higher than for C allele carriers. The expression levels of the lncRNA MALAT1 in cancer tissues was significantly higher than that in paracancerous tissues, while the hsa-miR-194-5p expression level was significantly lower in cancerous tissues compared to cognate paracancerous tissues. The progression-free survival (PFS) rate for patients with the MALAT1 gene rs664589 locus GG genotype was significantly lower than that of CG genotype patients. Moreover, lncRNA MALAT1 inhibited the expression of hsa-miR-194-5p. Conclusion: The risk of CRC was relatively higher among MALAT1 rs664589 G allele carriers, and the CRC patients with a G allele had a lower PFS. The likely mechanism underlying these observations is that the rs664589 SNP affects the binding efficiency between the lncRNA MALAT1 and the miRNA has-miR-194-5p, although this awaits laboratory confirmation.

The Long Noncoding RNA Metastasis-Associated Lung Adenocarcinoma Transcript-1 Regulates CCDC80 Expression by Targeting miR-141-3p/miR-200a-3p in Vascular Smooth Muscle Cells.

Our previous study showed that Coiled-Coil Domain Containing 80 (CCDC80) accelerates the development of atherosclerosis by decreasing lipoprotein lipase (LPL) expression and activity in apoE knockout mice. However, the regulatory mechanism for CCDC80 expression is unclear. This study was designed to evaluate whether noncoding RNAs involved the regulation of CCDC80 expression in vascular smooth muscle cells. Bioinformatics prediction and luciferase reporter gene results showed that miR-141-3p/200a-3p bound to the 3'UTR of CCDC80. Furthermore, miR-141-3p/200a-3p mimics decreased the expression of CCDC80 but increased LPL expression. Opposite results were observed with miR-141-3p/200a-3p inhibitors. We also found that lncRNA metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) interacted with the sequences of miR-141-3p/200a-3p and decreased their expression. RT-qPCR and western blotting results showed that MALAT1 overexpression increased CCDC80 expression and decreased LPL expression, while MALAT1 knockdown displayed an opposite phenotype. The effects of both MALAT1 overexpression and knockdown were blocked by miR-141-3p/200a-3p mimics or inhibitors. Thus, we demonstrated that lncRNA MALAT1 regulates CCDC80 and LPL expression through miR-141-3p/200a-3p.

M6A-induced lncRNA MALAT1 aggravates renal fibrogenesis in obstructive nephropathy through the miR-145/FAK pathway

Renal fibrosis is a key factor in chronic kidney disease (CKD). Long non-coding RNAs (lncRNAs) play important roles in the physiological and pathological progression of human diseases. However, the roles and underlying mechanisms of lncRNAs in renal fibrosis still need to be discovered. In this study, we first displayed the increased lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) expression in renal fibrosis in patients with obstructive nephropathy (ON). Then we found that transforming growth factor beta 1 (TGF-β1) induced epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) protein deposition, which promoted the viability, proliferation and migration of human renal proximal tubular epithelial (HK2) cells. Next, MALAT1/miR-145/focal adhesion kinase (FAK) pathway was confirmed to play an importment role in TGF-β1-induced renal fibrosis. In addition, the MALAT1/miR-145/FAK pathway was involved in the effect of dihydroartemisinin (DHA) on TGF-β1-induced renal fibrosis in vitro and in vivo. Furthermore, m6A methyltransferase methyltransferase-like 3 (METTL3) was shown to be the main methyltransferase of m6A modification on MALAT1.

LncRNA MALAT1 knockdown inhibits cell migration and invasion by suppressing autophagy through miR-384/GOLM1 axis in glioma.

Glioma is characterized by high metastasis with poor outcomes. Long non-coding RNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was well-explored in numerous human cancers, including glioma. This study aimed to provide a novel action mechanism of MALAT1 in glioma. The expression of MALAT1, microRNA-384 (miR-384) and Golgi membrane protein 1 (GOLM1) was detected by quantitative Real-time polymerase chain reaction (qRT-PCR). The protein levels of GOLM1, light chain3 (LC3-II/LC3-I), p62, Vimentin and E-cadherin were proved by Western blot. Cell migration and invasion were monitored using the transwell assay. Bioinformatics tool starBase was used to predict target genes and associated binding sites. RNA immunoprecipitation assay (RIP) and dual-luciferase reporter assay were utilized to verify the relationship between miR-384 and MALAT1 or GOLM1. Tumor formation analysis in nude mice was conducted to ascertain the role of MALAT1 in vivo. MALAT1 was highly expressed in glioma tissues and cells. MALAT1 knockdown inhibited autophagy, migration and invasion of glioma cells. MiR-384 was a target of MALAT1, and miR-384 inhibition reversed the effects of MALAT1 knockdown in glioma cells. GOLM1 was a target of miR-384, and miR-384 inhibition eliminated the function of GOLM1 downregulation in glioma cells. In addition, GOLM1 was regulated by MALAT1 through miR-384. Moreover, MALAT1 knockdown blocked tumor growth and development in vivo. MALAT1 knockdown depleted migration and invasion by inhibiting autophagy through MALAT1/miR-384/GOLM1 axis in glioma in vitro and in vivo. The MALAT1/miR-384/GOLM1 axis was first proposed in our report, enriching the action mechanism of MALAT1 in glioma.

Regulation of the Inflammatory Synovial Fibroblast Phenotype by Metastasis-Associated Lung Adenocarcinoma Transcript 1 Long Noncoding RNA in Obese Patients With Osteoarthritis.

To identify long noncoding RNAs (lncRNAs) associated with the inflammatory phenotype of synovial fibroblasts from obese patients with osteoarthritis (OA), and to explore the expression and function of these lncRNAs. Synovium was collected from normal-weight patients with hip fracture (non-OA; n = 6) and from normal-weight (n = 8) and obese (n = 8) patients with hip OA. Expression of RNA was determined by RNA-sequencing and quantitative reverse transcription-polymerase chain reaction. Knockdown of lncRNA was performed using LNA-based GapmeRs. Synovial fibroblast cytokine production was measured by enzyme-linked immunosorbent assay. Synovial fibroblasts from obese patients with OA secreted greater levels of interleukin-6 (IL-6) (mean ± SEM 162 ± 21 pg/ml; P < 0.001) and CXCL8 (262 ± 67 pg/ml; P < 0.05) compared to fibroblasts from normal-weight patients with OA (IL-6, 51 ± 4 pg/ml; CXCL8, 78 ± 11 pg/ml) or non-OA patients (IL-6, 35 ± 3 pg/ml; CXCL8, 56 ± 6 pg/ml) (n = 6 patients per group). RNA-sequencing revealed that fibroblasts from obese OA patients exhibited an inflammatory transcriptome, with increased expression of proinflammatory messenger RNAs (mRNAs) as compared to that in fibroblasts from normal-weight OA or non-OA patients (>2-fold change, P < 0.05; n = 4 patients per group). A total of 19 lncRNAs were differentially expressed between normal-weight OA and non-OA patient fibroblasts, and a further 19 lncRNAs were differentially expressed in fibroblasts from obese OA patients compared to normal-weight OA patients (>2-fold change, P < 0.05 for each), which included the lncRNA for metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). MALAT1 was rapidly induced upon stimulation of OA synovial fibroblasts with proinflammatory cytokines, and was up-regulated in the synovium from obese OA patients as compared to normal-weight OA patients (1.6-fold change, P < 0.001) or non-OA patients (6-fold change, P < 0.001). MALAT1 knockdown in OA synovial fibroblasts (n = 4 patients) decreased the levels of mRNA expression and protein secretion of CXCL8 (>1.5-fold change, P < 0.01), whereas it increased expression of mRNAs for TRIM6 (>2-fold change, P < 0.01), IL7R (<2-fold change, P < 0.01), HIST1H1C (>1.5-fold change, P < 0.001), and MAML3 (>1.5-fold change, P < 0.001). In addition, MALAT1 knockdown inhibited the proliferation of synovial fibroblasts from obese patients with OA. Synovial fibroblasts from obese patients with hip OA exhibit an inflammatory phenotype. MALAT1 lncRNA may mediate joint inflammation in obese OA patients.

Study on adsorption of microRNA-124 by long chain non-coding RNA MALAT1 regulates osteogenic differentiation of mesenchymal stem cells

To investigate the regulatory effect of long chain non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) adsorbing microRNA-124 (miR-124) on osteogenic differentiation of mesenchymal stem cells (MSCs). C3H10T1/2 cells derived from mouse embryos were cultured in vitro, then randomly divided into control group (group A), lncRNA MALAT1 no-load plasmid group (group B), lncRNA MALAT1 overexpression plasmid group (group C), lncRNA MALAT1 small interfering RNA (siRNA) group (group D), and lncRNA MALAT1 siRNA negative control group (group E). The cells were transfected into plasmids and siRNA, then induced to differentiate into osteoblasts. Alkaline phosphatase (ALP) and alizarin red staining were used to detect the osteogenic differentiation of cells in each group, real-time fluorescence quantitative (qRT-PCR) analysis was used to detect the expressions of lncRNA MALAT, miR-124, and osteogenesis-related genes such as Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and osteocalcin (OCN) in each group. Double luciferase reporter gene was used to detect the targeting regulation of lncRNA MALAT1 to miR-124. The relative contents of ALP positive cells, mineralized nodule, and the relative mRNA expressions of lncRNA MALAT1, Runx2, OPN, and OCN in group C were significantly higher than those in other groups ( P<0.05), while in group D significantly lower than in other groups ( P<0.05); the relative expression of miR-124 in group C was significantly lower than that in other groups( P<0.05), while in group D significantly higher than in other groups ( P<0.05). There was no significant difference in these indexes between groups A, B, and E ( P>0.05). The results of double luciferase reporter gene assay showed that lncRNA MALAT1 targeting down-regulated the expression of miR-124. LncRNA MALAT1 can targeting down-regulate the expression of miR-124 and promote the osteogenic differentiation of MSCs.

Thapsigargin promotes colorectal cancer cell migration through upregulation of lncRNA MALAT1.

Colorectal cancer (CRC) is the third most common tumor in the world; however, the role and mechanism of endoplasmic reticulum (ER) stress in CRC metastasis remains largely unclear. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA), which has previously been associated with CRC metastasis. It has been suggested that ER stress pathways regulate lncRNA expression; however, the effect of ER stress on MALAT1 expression in cancer is unknown. The present study aimed to investigate the relationship between ER stress pathways, MALAT1 expression and cell migration in CRC cells. ER stress was induced by thapsigargin (TG); low dose TG induced the migration of HT29 and HCT116 cells, but not SW1116 and SW620 cells. This effect was associated with increased expression levels of MALAT1, as the knockdown of MALAT1 prevented TG-induced cell migration. TG-induced MALAT1 expression was associated with inositol-requiring enzyme 1 (IRE1) expression and activation of the protein kinase R (PKR)-like ER kinase (PERK) signaling pathway. X-box-binding protein 1 (XBP1) and activating transcription factor 4 (ATF4) binding sites were predicted to be located in the MALAT1 gene promoter regions and the expression of MALAT1 was positively associated with XBP1 and ATF4 expression levels in CRC tissue samples. Thus, these findings indicated that ER stress may promote the migration of CRC cells and contribute to the progression of CRC through the activation of the IRE1/XBP1 and PERK/eIF2α/ATF4 signaling pathways. In conclusion, to the best of our knowledge, this study is the first report that lncRNA MALAT1 expression is regulated by the IRE1/XBP1 pathway in CRC.

Extracellular Vesicle lncRNA Metastasis-Associated Lung Adenocarcinoma Transcript 1 Released From Glioma Stem Cells Modulates the Inflammatory Response of Microglia After Lipopolysaccharide Stimulation Through Regulating miR-129-5p/High Mobility Group Box-1 Protein Axis.

Glioma stem cell (GSC)–derived extracellular vesicles (EVs) can mediate the communication between GSCs and microglia. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) expression in GSCs, EVs, and supernatant was detected by real-time PCR. The direct targeting between MALAT1 and miR-129-5p, miR-129-5p, and HMGB1 were tested with luciferase reporter analysis. The expression and secretion of interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α were determined in lipopolysaccharide-stimulated microglia or miR-129-5p inhibitor transferred to microglia exposed to GSC EVs or EVs derived from siMALAT1 pre-transferred GSCs. MALAT1 was enriched in GSC EVs compared with GSCs, and up-regulated MALAT1 was also observed in microglia upon GSC EVs incubation. The relative expression and secretion of IL-6, IL-8, and TNF-α in lipopolysaccharide-stimulated microglia were up-regulated in the GSC supernatant group, which could be reversed by dimethyl amiloride (DMA) (EV secretion inhibitor) co-administration or si-MALAT1 pre-transfection of GSCs. Luciferase reporter assay testified the direct binding of MALAT1 and miR-129-5p, miR-129-5p, and HMGB1, and si-MALAT1 could up-regulate miR-129-5p expression and down-regulate HMGB1 expression in microglia cells. The concentration of IL-6, IL-8, and TNF-α in lipopolysaccharide-stimulated microglia exposed to EVs from siMALAT1 transfected GSCs could be up-regulated by miR-129-5p inhibition. EVs lncRNA MALAT1 released from GSCs could modulate the inflammatory response of microglia after lipopolysaccharide stimulation through regulating the miR-129-5p/HMGB1 axis.

Downregulation of lncRNA MALAT1 suppresses abnormal proliferation of small intestinal epithelial stem cells through miR‑129‑5p expression in diabetic mice.

The problems caused by diabetes mellitus (DM) and its related complications are gaining increasing attention. In our previous study, the abnormal proliferation of small intestinal epithelial cells (IECs) were observed in diabetic mice. However, little is known regarding the potential underlying mechanism. In the present study, the abnormal proliferation of IECs in DM and the marked upregulation of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was observed. Additionally, knockdown of MALAT1 significantly reduced abnormal IESC proliferation in DM mice. Bioinformatics analysis and luciferase reporter assays revealed that microRNA (miR)‑129‑5p was directly targeted by MALAT1. Moreover, the results of the bioinformatics prediction and luciferase assays demonstrated that MALAT1 directly interacted with SRY‑box 9 (SOX9). Furthermore, MALAT1 silencing was observed to attenuate the abnormal proliferation of IESCs through the SOX9‑mediated WNT/β‑catenin signaling pathway. Knockdown of MALAT1 downregulated SOX9 expression by binding to miR‑129‑5p, thereby inhibiting the abnormal proliferation of IESCs via the WNT/β‑catenin signaling pathway.

Long Non-Coding RNA Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Promotes Hypertension by Modulating the Hsa-miR-124-3p/Nuclear Receptor Subfamily 3, Group C, Member 2 (NR3C2) and Hsa-miR-135a-5p/NR3C2 Axis.

BackgroundThis study was designed to investigate the role of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the proliferation as well as apoptosis of human umbilical vein endothelial cells (HUVECs), to offer a basis for therapy of hypertension.Material/MethodsThe lncRNA MALAT1 expression, hsa-miR-124-3p, hsa-miR-135a-5p, hsa-miR-135b-5p, and hsa-miR-455-5p in plasma were measured from 230 patients with hypertension and 230 non-hypertensive controls. The mechanism for lncRNA MALAT1 modulating the proliferation and apoptosis of HUVECs was explored by cell transfection, Cell Counting Kit-8 (CCK-8), quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and dual-luciferase reporter assays.ResultsThe expression of hsa-miR-124-3p and hsa-miR-135a-5p was reduced and the expression of lncRNA MALAT1 was increased in the plasma of hypertensive patients. Moreover, the plasma levels of hsa-miR-124-3p and hsa-miR-135a-5p of hypertensive patients were negatively correlated with lncRNA MALAT1 (r=−0.64, −0.72; P<0.01, P<0.01, respectively). The level of nuclear receptor subfamily 3, group C, member 2 (NR3C2) protein was negatively correlated with hsa-miR-124-3p and hsa-miR-135a-5p (r=−0.74, −0.84; P<0.01, P<0.01, respectively). The proliferation of HUVECs was inhibited after the inhibition of MALAT. Additionally, after knocking down MALAT, the levels of hsa-miR-124-3p and hsa-miR-135a-5p in HUVECs were markedly increased, while the expression level of NR3C2 protein was decreased. The apoptotic rate of HUVECs after the transfection of MALAT1 small interfering RNA (si-MALAT1) (3.64±0.21%) was significantly reduced compared to that of transfected si-MALAT1 no template control (NC) (3.76±0.19%) and the control group (10.51±1.24%).ConclusionsLncRNA MALAT1 regulates proliferation and apoptosis of HUVECs through the hsa-miR-124-3p/NR3C2 and/or hsa-miR-135a-5p/NR3C2 axis.