Metastasis-associated Lung Adenocarcinoma Transcript 1 Expression Research Articles

High-Dose Vitamin C Tends to Kill Colorectal Cancer with High MALAT1 Expression.

Background Vitamin C (Vc) deficiency is frequently observed in cancer sites and has been proposed to have an antitumor effect. However, the mechanism of Vc's killing effect is not clear. Besides, epigenetic alterations exhibit significant effects on colorectal cancer (CRC). This study aimed to explore the mechanism of Vc's killing effect and its association to epigenetic alterations in CRC. Methods Cell morphology, apoptosis, proliferation, and cycle were assayed to test Vc's suppressive function in CRC cell lines. Xenograft and peritoneal implantation metastasis models were performed to evaluate the high-dose Vc's inhibitory effect on tumor growth and metastasis. Immunohistochemistry was used to measure CD31 expression in solid tumors. A literature summary was applied for screening differently expressed long noncoding RNAs (lncRNAs) in CRC tissues and was closely associated with CRC progression. The qPCR was used to detect the expression of these lncRNAs. The association between Vc and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was evaluated in MALAT1-transfected CRC cells and a xenograft model. Results Vc was confirmed to function in proliferation suppression, apoptosis induction, and S phase arresting in CRC cell lines. High-dose Vc, but not physiologically low-dose Vc, was identified as a suppressive function on tumor growth in xenograft models and an inhibitory effect on implantation metastasis in peritoneal implantation metastasis mice. Furthermore, a consistent downregulation of MALAT1 induced by Vc was verified among CRC cell lines and tumor tissues from both mouse models. Finally, experiments on MALAT1-knockdown CRC cells and its xenograft model suggested that Vc had a tendency in killing CRC with high MALAT1 expression. Conclusions Our findings demonstrate that high-dose Vc has more efficiency in suppressing CRC with higher MALAT1 expression. It gives high-dose Vc the possibility of a better curative effect on CRC with overexpressed MALAT1. Further clinical studies are still needed.

The AMPK-mTOR axis requires increased MALAT1 expression for promoting granulosa cell proliferation in endometriosis.

Endometriosis is a common reproductive disorder in women, with a global prevalence of 10-15%. Long noncoding RNAs (lncRNAs) are critical to gene transcription, cell cycle modulation and immune response. The lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) reportedly mediates autophagy of endometrial stromal cells in endometriosis. The present study aimed to evaluate the role and mechanism of MALAT1 in granulosa cells (GCs) in endometriosis. Consequently, MALAT1 expression was upregulated in GCs obtained from patients with endometriosis and in the steroidogenic human granulosa-like tumor cell line KGN. However, MALAT1 knockdown consequently decreased the proliferation and viability of these cells, as determined by MTT and 5-ethynyl-2'-deoxyuridine staining assays. Both Annexin V-fluorescein isothiocyanate/propidium iodide flow cytometry and western blotting performed to detect proapoptotic factors indicated that MALAT1 depletion might promote KGN cell apoptosis. Furthermore, MALAT1 knockdown increased GC autophagy, as evidenced by microtubule-associated protein 1A/1B-light chain 3 (LC3) cleavage upregulation and p62 degradation. In addition, although 5'-AMP-activated protein kinase (AMPK) mRNA expression and protein levels decreased in GCs obtained from patients with endometriosis and KGN cells, MALAT1 knockdown restored AMPK levels. However, addition of BML-275 (MALAT1 inhibitor) to MALAT1-knockdown KGN cells recovered their viability and proliferative capacity and simultaneously reduced their apoptotic and autophagic capacity. Therefore, MALAT1 may regulate GC proliferation via AMPK-mTOR-mediated cell apoptosis and autophagy.

The expression and clinical significance of three lncRNAs in patients with a missed abortion.

Missed abortions are common complications that occur in early pregnancy, and impaired trophoblast functions have been indicated to be associated with their pathogenesis. The long noncoding RNAs (lncRNAs) Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), HOX Transcript Antisense RNA (HOTAIR) and Maternally expressed gene 3 (MEG3) have been demonstrated to serve a crucial regulatory role in the mobility of trophoblast cells and embryo implantation. However, the expression profile and role of each of these three lncRNAs in patients with a missed abortion remain unclear. The expression of MALAT1, HOTAIR, and MEG3 in decidual and villous tissues from 26 patient exhibiting a missed abortion and 26 healthy controls was detected using reverse-transcription quantitative PCR. Serum TNF-α, IL-1β, IL-6 and IL-10 levels were measured using ELISA, and serum estradiol and progesterone levels were measured with electrochemiluminescence immunoassays. Additionally, the correlations between lncRNA expression and the levels of cytokines and hormones were further analyzed. MALAT1, HOTAIR and MEG3 expression was significantly higher in villous tissues of patients exhibiting a missed abortion compared with healthy controls. MALAT1 expression was higher in decidual tissues of patients exhibiting a missed abortion compared with healthy controls. Serum IL-10 levels were significantly lower in patients exhibiting a missed abortion compared with healthy controls. Serum estradiol and progesterone levels were significantly lower in the group of patients exhibiting a missed abortion compared with the control group. Furthermore, MALAT1 expression in villous tissue was inversely related to serum progesterone levels. The results of the current study suggest that MALAT1 may be associated with the pathogenesis of missed abortions.

<p>LncRNA MALAT1 Promotes Survival of Epithelial Ovarian Cancer Cells by Downregulating miR-145-5p</p>

PurposeThis paper was aimed at investigating the regulatory mechanism of long non-coding RNA metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) in epithelial ovarian cancer (EOC).Materials and MethodsMALAT1 and miR-145-5p expression in the tissues, serum, and EOC cell lines (TOV-112D, TOV-21G) of patients with EOC were detected. The two genes were transfected into the cells via upregulating or downregulating their expression. Levels of apoptosis-related proteins (Caspase-3, Bax, Bcl-2) were analyzed. Mechanisms of cell proliferation, invasion, and apoptosis were studied.ResultsMALAT1 was high expressed in EOC tissues, while miR-145-5p was poorly expressed in them. The areas under the curves (AUCs) of the two genes for diagnosing EOC were greater than 0.850, and the two had a significantly negative correlation. According to multivariate Cox regression analysis, high MALAT1 expression, tumor size, degree of differentiation, case staging, and lymph node metastasis were the independent risk factors affecting prognosis. The 5-year overall survival rate (OSR) of patients with low MALAT1 expression was remarkably higher than that of those with high expression. Overexpressing miR-145-5p and silencing MALAT1 could inhibit EOC cells from proliferating and invading, increase their apoptotic rate, and improve levels of the apoptosis-related proteins. After co-transfection with MALAT1-inhibitor + miR-145-5p-inhibitor, the proliferation and invasion of TOV-112D and TOV-21G cells were inhibited and the apoptotic rate rose more obviously. Inhibiting MALAT1 could increase miR-145-5p expression, thus inhibiting EOC cells from proliferating and invading and thereby increasing their apoptotic rate.ConclusionMALAT1 promotes EOC cells’ survival by downregulating miR-145-5p so it may become a new direction for EOC diagnosis and gene therapy.

LncRNA MALAT1 facilitates BM-MSCs differentiation into endothelial cells via targeting miR-206/VEGFA axis

ABSTRACT Bone marrow-derived mesenchymal stem cells (BM-MSCs) implantation shows a repair effect on erectile function in diabetes mellitus-induced erectile dysfunction (DMED) due to its differentiative capacity into endothelial cells (ECs) that contributes to endothelial repair. This study was designed to explore the functional role and mechanism of long noncoding RNA (lncRNA)-metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in BM-MSCs-mediated DMED repairing. The DMED rat model was established and the erectile function was evaluated by calculating the intracavernous pressure (ICP)/mean arterial pressure (MAP) ratio in the DMED models with or without BM-MSCs implantation. The differentiation of BM-MSCs toward ECs was assessed by measuring the expression of EC-specific genes. RNA pull-down and luciferase reporter assay were performed to explore the interaction between miR-206 and MALAT1 or VEGFA. BM-MSCs implantation improved the erectile function of DMED rats and increased MALAT1 expression. MALAT1 was time-dependently upregulated during the VEGF-induced BM-MSCs differentiation into ECs. Mechanistically, MALAT1 acted as a sponge of miR-206 to upregulate VEGFA expression, thereby promoting the differentiation of BM-MSCs into ECs. Moreover, MALAT1 silencing in vivo impaired the repairing effect of BM-MSCs on erectile dysfunction. Collectively, MALAT1 facilitates BM-MSCs differentiation into ECs via regulating miR-206/VEGFA axis.

The lncRNA MALAT1/miR-30/Spastin Axis Regulates Hippocampal Neurite Outgrowth.

Spastin, a microtubule-severing enzyme, is important for neurite outgrowth. However, the mechanisms underlying the post-transcriptional regulation of spastin during microtubule-related processes are largely unknown. We demonstrated that the spastin expression level is controlled by a long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/microRNA-30 (miR-30) axis during neurite outgrowth. The miR-30 expression level decreased in hippocampal neurons with increasing days in culture, and miR-30 overexpression suppressed while miR-30 inhibition promoted neurite outgrowth in hippocampal neurons. Spastin was validated as a target gene of miR-30 using the luciferase reporter assay. The protein expression, microtubule severing activity, and neurite promoting effect of spastin were suppressed by the overexpression of miR-30 mimics and increased by miR-30 inhibitors. MALAT1 expression increased during neurite outgrowth and MALAT1 silencing impaired neurite outgrowth. miR-30 was a sponge target of MALAT1 and MALAT1/miR-30 altered neurite outgrowth in hippocampal neurons. MALAT1 overexpression reversed the inhibitory effect of miR-30 on the activity of a luciferase reporter construct containing spastin, as well as spastin mRNA and protein expression, indicating that spastin was a downstream effector of MALAT1/miR-30. The MALAT1/miR-30 cascade also modulated spastin-induced microtubule severing, and the MALAT1/miR-30/spastin axis regulated neurite outgrowth in hippocampal neurons. This study suggests a new mechanism governing neurite outgrowth in hippocampal neurons involving MALAT1/miR-30-regulated spastin expression.

Long Non-coding RNA MALAT1 Upregulates ZEB2 Expression to Promote Malignant Progression of Glioma by Attenuating miR-124.

Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been shown to play a critical role in the development of several malignancies. However, the potential molecular mechanism of MALAT1 in glioma remains unclear. In the present study, we found that the expression of MALAT1 was aberrantly increased in both human glioma tissues and cells and associated with poor prognosis in glioma patients. We further found that MALAT1 silencing significantly inhibited glioma cell proliferation while induced cell cycle arrest and apoptosis. In parallel, knockdown of MALAT1 decreased tumor volume in vivo. These results suggested that MALAT1 acts as a functional oncogene, resulting in the oncogenicity in glioma. Nevertheless, the tumor-suppressive effect of MALAT1 silencing was reversed by miR-124. Besides, the relevance of ZEB2 in tumor progression has been studied in several forms of human cancer, and ZEB2 was identified as a target of miR-124 and negatively regulated by miR-124. MALAT1 overexpression or miR-124 inhibitor led to increased expression of ZEB2. In summary, our study depicts a novel pathway of MALAT1/miR-124/ZEB2 that regulates the progression of glioma and might provide a promising strategy for glioma therapy.

Prognostic and clinicopathological significance of long noncoding RNA MALAT-1 expression in patients with non-small cell lung cancer: A meta-analysis.

Although expression of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) in tumor tissues has been assessed in several malignancies. However, the association between lncRNA MALAT-1 expression and prognosis or clinicopathological feature remains controversial. Therefore, we conducted a meta-analysis to verify whether lncRNA MALAT-1 expression was associated with prognosis or clinicopathological features in patients with non-small cell lung cancer (NSCLC). We searched Embase, PubMed, Web of Science, Cochrane library, The Chinese National Knowledge Infrastructure, and Wanfang databases from inception to March, 1, 2020. The language restrictions were Chinese and English. The published literature on lncRNA MALAT-l expression and prognosis or clinicopathological characteristics of NSCLC patients was statistically analyzed. Combined hazard ratios (HRs), odds ratios (OR), and 95% confidence intervals (95% CIs) were used to evaluate the effects of lncRNA MALAT-l on the prognosis and clinicopathological features of NSCLC. Fifteen studies with 1477 NSCLC patients were enrolled. The results showed that the elevated expression of lncRNA MALAT-l in tumor tissues was associated with shorter overall survival (OS) (HR: 2.20, 95% CI: 1.53-3.16; P = 0.000). Additionally, high lncRNA MALAT-l expression was also significantly associated with gender (OR: 0.69, 95% CI: 0.51-0.93; P = 0.014), tumor size (OR: 1.87, 95% CI:1.13-3.09; P = 0.016), lymph node metastasis (LNM) (OR: 2.87, 95% CI:1.05-7.83, P = 0.04), tumor differentiation (OR: 1.60, 95% CI:1.17-2.20; P = 0.003), and tumor-node-metastasis (TNM) stage (OR: 0.42, 95% CI: 0.25-0.70; P = 0.001). There was no significant relationship between lncRNA MALAT-l expression and other clinicopathological features including age (OR: 1.03, 95% CI: 0.79-1.34; P = 0.830), number of tumors (OR: 1.02, 95% CI: 0.63-1.64; P = 0.943), vascular invasion (OR: 1.23, 95% CI: 0.50-3.05; P = 0.652), and recurrence (OR: 1.98, 95% CI: 0.67-5.85; P = 0.214). The overexpression of lncRNA MALAT-l in NSCLC tissues was correlated with OS, gender, tumor size, LNM, tumor differentiation, and TNM stage. Thus, lncRNA MALAT-l may serve as a prognostic factor for NSCLC.

LncRNA MALAT1 Affects Mycoplasma pneumoniae Pneumonia via NF-κB Regulation.

Our aim was to determine whether the long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is involved in Mycoplasma pneumoniae pneumonia (MPP), and its possible mechanism of action. MALAT1 expression in the bronchoalveolar lavage fluid of 50 hospitalized children with MPP was compared to its expression in 30 children with intrabronchial foreign bodies. MALAT1 expression was higher in children with MPP, accompanied by increased inflammatory mediators interleukin 8 (IL-8) and tumor necrosis factor alpha (TNF-α), compared to the controls. In human airway epithelial cells infected with wild-type Mycoplasma pneumoniae (strain M129), MALAT1, IL-8, and TNF-α expression significantly increased, and increased expression of IL-8 and TNF-α could be suppressed by MALAT1 knockdown. Luciferase reporter gene assay and western blot showed that knockdown of MALAT1 reduced nuclear factor-κB (NF-κB) activation. In vivo, RNAi packaged with adenovirus (Adv) was nasally transfected into BALB/c mice to silence MALAT1, and an MP-infected mouse pneumonia model was prepared. The results demonstrated that the degree of pulmonary inflammatory injury, vascular permeability, secretion of inflammatory factors, and expression of phosphorylated p65 (pp65) in MP-infected mice were partly reversed after MALAT1 knockdown compared to those in the controls. In conclusion, MALAT1 is involved in the regulation of airway and pulmonary inflammation caused by MP infection via NF-κB regulation.

LncRNA-MALAT1 expression in patients with coronary atherosclerosis and its predictive value for in-stent restenosis.

This study was designed to investigate the long non-coding RNA (lncRNA)-metastasis associated lung adenocarcinoma transcript 1 (MALAT1) expression in patients with coronary atherosclerosis and its predictive value for in-stent restenosis. Ninety-five patients with coronary heart disease who came to our hospital for treatment and underwent stent implantation were selected as a research group (RG), and 95 volunteers undergoing physical examination who did not suffer from coronary heart disease during the same period were selected as a control group (CG). MALAT1 of subjects in both groups before and after treatment were detected by RT-qPCR, and N-terminal pro-brain natriuretic peptide (NT-proBNP), high sensitivity C-reactive protein (hs-CRP), lactate dehydrogenase (LDH), and creatine kinase isoenzyme (CK-MB) of them in the RG before treatment were detected. The level was evaluated and detected, and its correlation with MALAT1 was analyzed. Then, the predictive value of MALAT1 for in-stent restenosis in patients with coronary heart disease was analyzed. MALAT1 expression in patients with coronary heart disease was higher than that of normal subjects (P<0.05); after treatment, the expression levels of MALAT1, NT-proBNP, hs-CRP, LDH, and CK-MB in the serum of patients were significantly lower than those before treatment (P<0.05); MALAT1 expression was positively correlated with the expression levels of NT-proBNP, hs-CRP, LDH, and CK-MB (P<0.05). Receiver operating characteristic of MALAT1 for predicting in-stent restenosis in patients with coronary heart disease was over 0.8; the number of lesions, MALAT1, diabetes, NT-proBNP and hs-CRP were independent risk factors for in-stent restenosis. MALAT1 is highly expressed in the serum of patients with coronary heart disease, and it has high value in its diagnosis and the prediction of in-stent restenosis. It is also an independent risk factor for in-stent restenosis in patients with coronary heart disease.

LncRNA MALAT1 Aggravates the Progression of Non-Small Cell Lung Cancer by Stimulating the Expression of COMMD8 via Targeting miR-613.

BackgroundNon-small cell lung cancer (NSCLC) is a common malignant tumor in humans. Long non-coding RNA (lncRNA) involved in cancer progression has been reported frequently. The objective of this study was to investigate the role of lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and explore a novel mechanism in NSCLC development.Materials and MethodsThe expression of MALAT1, copper metabolism MURR1 domain-containing 8 (COMMD8) and microRNA-613 (miR-613) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of COMMD8, Cyclin D1, Ki67, B cell lymphoma/leukemia-2 (Bcl-2), Bcl-2 associated X protein (Bax), lactate dehydrogenase A (LDHA), CD63 and CD81 were determined by Western blot. Cell proliferation, the number of colonies and cell apoptosis were assessed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), colony formation and flow cytometry assays, respectively. Glycolysis was distinguished based on glucose consumption, lactate production and LDHA activity. The role of MALAT1 in vivo was verified by animal experiments. The relationship between miR-613 and MALAT1 or COMMD8 was predicted by the bioinformatics tool starbase and verified by dual-luciferase reporter assay. The exosomes were isolated using the corresponding kit and identified by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA).ResultsMALAT1 and COMMD8 were aberrantly upregulated in NSCLC tissues and cells. MALAT1 or COMMD8 knockdown blocked cell proliferation, colony formation and glycolysis but accelerated cell apoptosis in vitro. Besides, MALAT1 knockdown reduced tumor growth in vivo. We found that miR-613 was a target of MALAT1, and miR-613 could bind to the 3ʹ untranslated region (3ʹUTR) of COMMD8. MALAT1 regulated the expression of COMMD8 by absorbing miR-613. Moreover, the extracellular MALAT1 was transmitted by wrapping into exosomes.ConclusionMALAT1 promoted malignant activities of NSCLC cells through targeting miR-613/COMMD8 axis, and exosome-mediated transfer of NSCLC might be a novel approach for NSCLC treatment.

Oncogenic Role of Long Noncoding RNAMALAT1 in Thyroid Cancer Progression through Regulation of the miR-204/IGF2BP2/m6A-MYC Signaling

Accumulating studies highlight the role of long noncoding RNAs (lncRNAs)/microRNAs (miRNAs)/messenger RNAs (mRNAs) as important regulatory networks in various human cancers, including thyroid cancer (TC). This study aimed to investigate a novel regulatory network dependent on lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in relation to TC development. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot were initially employed to detect the expression of MALAT1, insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), and myelocytomatosis (MYC) in TC cells. Interactions among MALAT1, miR-204, and IGF2BP2 were then identified in vitro. The biological processes of proliferation, migration, invasion, and apoptosis were evaluated in vitro via gain- and loss-of-function experiments, followed by in vivo validation using xenograft mice. Our data indicated that MALAT1 and IGF2BP2 were highly expressed, while miR-204 was poorly expressed in TC. IGF2BP2 was verified as a target of miR-204. MALAT1 was found to upregulate IGF2BP2 and enhance MYC expression via m6A modification recognition by competitively binding to miR-204, conferring a stimulatory effect on proliferation, migration, and invasion of TC cells, which was accompanied by weakened tumor growth and cell apoptosis. Altogether, the central findings of our study suggest that MALAT1 contributes to TC progression through the upregulation of IGF2BP2 by binding to miR-204.

Hyperbaric oxygen-induced long non-coding RNA MALAT1 exosomes suppress MicroRNA-92a expression in a rat model of acute myocardial infarction.

Hyperbaric oxygen (HBO) improves angiogenesis. The effect of HBO on metastasis‐associated lung adenocarcinoma transcript 1 (MALAT1), a pro‐angiogenic long non‐coding RNA, in cardiac myocyte‐derived exosomes and acute myocardial infarction (AMI) is unknown. We aimed to investigate whether MALAT1 is altered in cardiac myocyte‐derived exosomes in response to HBO as well as the molecular regulatory mechanisms of MALAT1 in cardiac myocytes treated with HBO. Cardiac myocytes were cultured, and HBO was applied at 2.5 atmosphere absolute in a hyperbaric chamber. Exosomes were extracted from the culture media. A rat model of AMI generated by the ligation of the left anterior descending artery was used. HBO significantly increased MALAT1 expression in cardiac myocytes and HBO‐induced MALAT1 and exosomes attenuated miR‐92a expression after myocardial infarction. Expression of krüppel‐like factor 2 (KLF2) and CD31 was significantly decreased after infarction and HBO‐induced exosomes significantly reversed the expression. Silencing of MALAT1 using MALAT1‐locked nucleic acid GapmeR significantly attenuated KLF2 and CD31 protein expression after infarction induced by HBO‐induced exosomes. HBO‐induced exosomes also decreased infarct size significantly. HBO‐induced exosomes from cardiac myocytes up‐regulate MALAT1 to suppress miR‐92a expression and counteract the inhibitory effect of miR‐92a on KLF2 and CD31 expression in left ventricular myocardium after myocardial infarction to enhance neovascularization.

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.

Elevated long noncoding RNA MALAT-1 expression is predictive of poor prognosis in patients with breast cancer: a meta-analysis.

Accumulating evidence indicates that aberrant regulation of metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1), a long noncoding RNA (lncRNA), plays a vital role in tumorigenesis. However, its association with breast cancer has not been systematically evaluated. In the current study, a meta-analysis was conducted to clarify the association between MALAT-1 and the prognosis and clinicopathological features of breast cancer. Relevant literature published in several databases was searched. Hazard ratio (HR) and odds ratio (OR) with 95% confidence interval (CI) were calculated to evaluate the effect of MALAT-1 expression on the survival outcomes and clinicopathological features of breast cancer. A total of 12 studies involving 4106 patients were identified. Pooled HR demonstrated that elevated MALAT-1 expression significantly predicted unfavorable overall survival (HR = 2.06, 95% CI: 1.66–2.56, P<0.0001) in patients with breast cancer. Subgroup analysis stratified by cancer type, sample size, and method of variance analysis also showed statistically significant associations. Additionally, the HR of patients with up-regulated MALAT-1 expression concerning disease-free survival (DFS), recurrence-free survival (RFS), and disease-specific survival (DSS) was 1.91 (95% CI: 1.53–2.39, P<0.0001). Further, elevated MALAT-1 expression was positively correlated with the progesterone receptor (PR) status (OR = 1.47, 95% CI: 1.18–1.82). Thus, MALAT-1 is a promising biomarker for predicting survival outcomes in patients with breast cancer.

Exercise-mediated downregulation of MALAT1 expression and implications in primary and secondary cancer prevention

Long non-coding RNAs (lncRNAs) play critical roles in various biological functions and disease processes including cancer. The metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was initially identified as a lncRNA with elevated expression in primary human non-small cell lung tumors with high propensity to metastasize, and subsequently shown to be highly expressed in numerous other human cancers including breast, ovarian, prostate, cervical, endometrial, gastric, pancreatic, sarcoma, colorectal, bladder, brain, multiple myeloma, and lymphoma.MALAT1 is deeply involved in several physiological processes, including alternative splicing, epigenetic modification of gene expression, cellular senescence, healthy aging, and redox homeostasis.The aim of this work was to investigate the modulation exerted by a single bout of endurance exercise on the level of MALAT1 expression in peripheral blood mononuclear cells (PBMCs) from healthy male donors displaying different training status and redox homeostasis features. Our findings show that MALAT1 is downregulated after acute endurance exercise in subjects whose fitness level guarantee a high expression of SOD1 and SOD2 antioxidant genes and low levels of endogenous oxidative damage. In vitro protocols in Jurkat lymphoblastoid cells exposed to pro-oxidant environment confirmed the link between MALAT1 expression and antioxidant gene modulation, documenting p53 phosphorylation and its recruitment to MALAT1 promoter. Remarkably, analyses of Microarray-Based Gene Expression Profiling revealed high MALAT1 expression in leukemia patients in comparison to healthy control and a significant negative correlation between MALAT1 and SOD1 expression.Collectively our results highlight the beneficial effect of a physically active lifestyle in counteracting aberrant cancer-related gene expression programs by improving the redox buffering capacity.

An allele of rs619586 polymorphism in MALAT1 alters the invasiveness of meningioma via modulating the expression of collagen type V alpha (COL5A1).

The rs619586 polymorphism has been shown to alter the expression of MALAT1, which act as a competing endogenous RNA (ceRNA) against miR‐145. And miR‐145 was found to target COL5A1, the interaction between which was shown to be involved in the pathogenesis of invasive meningioma. In this study, we aimed to explore the effect of rs619586 polymorphism and its underlying molecular mechanism in invasive meningioma. Real‐time PCR and Western Blot analysis were used to study the differentiated expression of miR‐145, MALAT1 (metastasis‐associated lung adenocarcinoma transcript 1) and COL5A1 (collagen alpha‐1(V) chain) in tumour/serum samples genotyped as rs619586 AA, AG and GG. Computational analysis and luciferase reporter assay were also conducted to identify the regulatory relationship between miR‐145 and MALAT1/COL5A1. Meanwhile, expression of miR‐145 and COL5A1 in different cell treatment groups was measured to validate the results obtained from earlier experiments. As shown by the results and in tumour/serum samples genotyped as AA, AG and GG, the expression of both MALAT1 and COL5A1 was down‐regulated in a stepwise fashion, while the expression of miR‐145 was increased, suggesting a potential negative relationship between MALAT1/COL5A1 and miR‐145. Meanwhile, miR‐145 was shown to bind to MALAT1, while COL5A1 was identified as a virtual target gene of miR‐145. As a consequence, a MALAT1/miR‐145/COL5A1 molecular pathway was established based on the above results. In particular, with the presence of rs619586 A>G polymorphism, the expression of MALAT1 and COL5A1 was both reduced, leading to reduced invasiveness of meningioma.

Long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 regulates renal cancer cell migration via cofilin-1.

Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is upregulated in numerous types of cancer, and is implicated in various cellular processes associated with cancer progression. However, the underlying molecular mechanisms by which MALAT1 regulates metastasis remain unclear. The present study investigated the expression of MALAT1 across a range of different cancer types by analyzing RNA sequencing data from The Cancer Genome Atlas database. The results indicate that the expression of MALAT1 is highly tissue-dependent and that MALAT1 is significantly overexpressed in renal clear cell carcinoma (KIRC). The biological role of MALAT1 in regulating KIRC cell migration was further investigated using molecular and cellular assays. The results demonstrate that MALAT1 regulates the expression of cofilin-1 (CFL1), potentially by regulating RNA splicing. MALAT1 knockdown decreased the expression of CFL1 at both the mRNA and protein levels, and affected cytoskeletal rearrangement by regulating the levels of F-actin via CFL1, leading to significantly decreased cellular migration. Clinical analysis confirmed a significant correlation between MALAT1 and CFL1 expression, implicating both genes as biomarkers for poor prognosis in KIRC. The present study demonstrates a novel mechanism by which MALAT1 regulates cell migration, which may be exploited to develop novel therapeutic strategies for managing renal cancer metastasis.