Metastasis-associated Lung Adenocarcinoma Transcript 1 Expression Research Articles

Exosomal MALAT1 from macrophages treated with high levels of glucose upregulates LC3B expression via miR-204-5p downregulation.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) plays a critical role in the pathophysiology of diabetes-related complications. However, whether macrophage-derived MALAT1 affects autophagic activity under hyperglycemic conditions is unclear. Therefore, we investigated the molecular regulatory mechanisms of macrophage-derived MALAT1 and autophagy under hyperglycemic conditions. Hyperglycemia was induced by culturing macrophages in 25 mM glucose for 1 h. Exosomes were extracted from the culture media. A rat model of carotid artery balloon injury was established to assess the effect of MALAT1 on vascular injury. Reverse transcription, real-time quantitative polymerase chain reaction, western blotting, immunohistochemical staining, and luciferase activity assays were performed. Stimulation with high levels of glucose significantly enhanced MALAT1 expression in macrophage-derived exosomes. MALAT1 inhibited miR-204-5p expression in macrophage-derived exosomes under hyperglycemic conditions. siRNA-induced silencing of MALAT1 significantly reversed macrophage-derived exosome-induced miR-204-5p expression. Hyperglycemic treatment caused a significant, exosome-induced increase in the expression of the autophagy marker LC3B in macrophages. Silencing MALAT1 and overexpression of miR-204-5p significantly decreased LC3B expression induced by macrophage-derived exosomes. Overexpression of miR-204-5p significantly reduced LC3B luciferase activity induced by macrophage-derived exosomes. Balloon injury to the carotid artery in rats significantly enhanced MALAT1 and LC3B expression, and significantly reduced miR-204-5p expression in carotid artery tissue. Silencing MALAT1 significantly reversed miR-204-5p expression in carotid artery tissue after balloon injury. MALAT1 silencing or miR-204-5p overexpression significantly reduced LC3B expression after balloon injury. This study demonstrated that hyperglycemia upregulates MALAT1. MALAT1 suppresses miR-204-5p expression and counteracts the inhibitory effect of miR-204-5p on LC3B expression in macrophages to promote vascular disease.

MALAT1: A Long Non-Coding RNA with Multiple Functions and Its Role in Processes Associated with Fat Deposition.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) belongs to the lncRNA molecules, which are involved in transcriptional and epigenetic regulation and the control of gene expression, including the mechanism of chromatin remodeling. MALAT1 was first discovered during carcinogenesis in lung adenocarcinoma, hence its name. In humans, 66 of its isoforms have been identified, and in pigs, only 2 are predicted, for which information is available in Ensembl databases (Ensembl Release 111). MALAT1 is expressed in numerous tissues, including adipose, adrenal gland, heart, kidney, liver, ovary, pancreas, sigmoid colon, small intestine, spleen, and testis. MALAT1, as an lncRNA, shows a wide range of functions. It is involved in the regulation of the cell cycle, where it has pro-proliferative effects and high cellular levels during the G1/S and mitotic (M) phases. Moreover, it is involved in invasion, metastasis, and angiogenesis, and it has a crucial function in alternative splicing during carcinogenesis. In addition, MALAT1 plays a significant role in the processes of fat deposition and adipogenesis. The human adipose tissue stem cells, during differentiation into adipocytes, secrete MALAT1 as one the most abundant lncRNAs in the exosomes. MALAT1 expression in fat tissue is positively correlated with adipogenic FABP4 and LPL. This lncRNA is involved in the regulation of PPARγ at the transcription stage, fatty acid metabolism, and insulin signaling. The wide range of MALAT1 functions makes it an interesting target in studies searching for drugs to prevent obesity development in humans. In turn, in farm animals, it can be a source of selection markers to control the fat tissue content.

Long non-coding RNA MALAT1 in hematological malignancies and its clinical applications.

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a well-established oncogenic long non-coding RNA, the higher expression of which is strongly correlated with cancer events such as tumorigenesis, progression, metastasis, drug resistance, and treatment outcome in solid cancers. Recently, a series of studies has highlighted its potential role in hematological malignancies in terms of these events. Similar to solid cancers, MALAT1 can regulate various target genes via sponging and epigenetic mechanisms, but the miRNAs sponged by MALAT1 differ from those identified in solid cancers. In this review, we systematically describe the role and underlying mechanisms of MALAT1 in multiple types of hematological malignancies, including regulation of cell proliferation, metastasis, stress response, and glycolysis. Clinically, MALAT1 expression is related to poor treatment outcome and drug resistance, therefore exhibiting potential prognostic value in multiple myeloma, lymphoma, and leukemia. Finally, we discuss the evaluation of MALAT1 as a novel therapeutic target against cancer in preclinical studies.

Predictive value of peripheral blood leukocytes-based methylation of Long non-coding RNA MALAT1 and H19 in the chemotherapy effect and prognosis of gastric cancer

BackgroundThe predictive value of the methylation of Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and H19 promoters in peripheral blood leukocytes as a non-invasive biomarker for the chemotherapy effect and prognosis gastric cancer (GC) is unclear. MethodsThe DNA methylation of H19 and MALAT1 between chemotherapy-sensitive and non-sensitive groups and between groups with better and worse survival of GC was compared using regression analyses. Several predictive nomograms were constructed. The genetic alteration of MALAT1 and H19 and the association between gene expression and immune status in GC were also investigated using bioinformatics analysis. ResultsHigher genetic methylations in peripheral blood were noticed in GC groups with poorer survival. The constructed nomograms presented strong predictive values for the chemotherapy effect and 3-year survival of disease-free survival, progression-free survival, and overall survival, with the area under the curve as 0.838, 0.838, 0.912, and 0.925, respectively. Significant correlations between MALAT1 or H19 expression and marker genes of immune checkpoints and immune pathways were noticed. The high infiltration of macrophages in H19-high and low infiltration of CD8+ T cells in MALAT1-high groups were associated with worse survival of GC. ConclusionsMALAT1 and H19 have the potential to predict the chemotherapy response and clinical outcomes of GC.

Expression and diagnostic value of lncRNA MALAT1 and NLRP3 in lower limb atherosclerosis in diabetes

ObjectiveThis study aimed to examine the diagnostic predictive value of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1(MALAT1) and NOD-like receptor protein 3(NLRP3) expression in patients with type 2 diabetes mellitus(T2DM) and lower extremity atherosclerosis disease (LEAD).MethodsA total of 162 T2DM patients were divided into T2DM with LEAD group (T2DM + LEAD group) and T2DM alone group (T2DM group). The lncRNA MALAT1 and NLRP3 expression levels were measured in peripheral blood, and their correlation was examined. Least absolute shrinkage and selection operator (LASSO) regression model was used to screen for the best predictors of LEAD, and multivariate logistic regression was used to establish a predictive model and construct the nomogram. The effectiveness of the nomogram was assessed using the receiver operating characteristic (ROC) curve, area under the curve (AUC), calibration curve, and decision curve analysis (DCA).ResultsThe levels of the lncRNA MALAT1 and NLRP3 in the T2DM + LEAD group were significantly greater than those in the T2DM group (P <0.001), and the level of the lncRNA MALAT1 was positively correlated with that of NLRP3 (r = 0.453, P<0.001). The results of the LASSO combined with the logistic regression analysis showed that age, smoking, systolic blood pressure (SBP), NLRP3, and MALAT1 were the influencing factors of T2DM with LEAD(P<0.05). ROC curve analysis comparison: The discriminatory ability of the model (AUC = 0.898), MALAT1 (AUC = 0.804), and NLRP3 (AUC = 0.794) was greater than that of the other indicators, and the predictive value of the model was the greatest. Calibration curve: The nomogram model was consistent in predicting the occurrence of LEAD in patients with T2DM (Cindex = 0.898). Decision curve: The net benefit rates obtained from using the predictive models for clinical intervention decision-making were greater than those obtained from using the individual factors within the model.ConclusionMALAT1 and NLRP3 expression increased significantly in T2DM patients with LEAD, while revealing the correlation between MALAT1 and NLRP3. The lncRNA MALAT1 was found as a potential biomarker for T2DM with LEAD.

MALAT1 expression in granulosa cells in PCOS patients with different phenotypes

Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine metabolic disorders. The lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) reportedly can regulate the reproductive system. Despite studies, the alteration of MALAT1 expression in granulosa cells (GCs) from PCOS patients was inconsistent. To evaluate MALAT1 expression in GCs in different PCOS subgroups and its association with PCOS phenotypes, we collected GCs from 110 PCOS cases and 71 controls, and examined MALAT1 expression by quantitative PCR. The results showed MALAT1 expression was upregulated in PCOS cases, especially in insulin resistant (IR) PCOS subgroup, obese PCOS subgroup and non-hyperandrogenic (NHA) PCOS subgroup. MALAT1 expression was positively correlated with BMI and several metabolic parameters in controls. Interestingly, MALAT1 expression was notably associated with some critical endocrine indexes for PCOS, including E2, FSH, LH and LH/FSH ratio. In different PCOS subgroups, we found significant positive correlations with LH/FSH ratio in IR-PCOS and PCOS with normal weight, and with serum T and LH level in NHA-PCOS subgroup. Integrated analysis with lncRNA target databases and PCOS-related databases revealed MALAT1 could participate in PCOS by influencing immune response and lipids metabolism in GCs. In conclusion, MALAT1 was differently expressed in GCs in PCOS, especially in IR, obese and NHA PCOS subgroups. MALAT1 was likely involved in metabolism and immune response in GCs in PCOS. However, more studies are necessary to establish this concept.

Mechanistic actions of long non-coding RNA MALAT1 within the ovary and at the feto-maternal interface.

Long non-coding RNAs (LncRNAs) are being unveiled as crucial regulators of several biological processes and pathways. Among the lncRNAs is metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), which is also known as nuclear enriched abundant transcript 2 (NEAT2). MALAT1 is highly conserved in mammals, and controls cellular processes such as proliferation, migration, invasion, angiogenesis, and apoptosis in both physiological and pathological conditions. Roles of MALAT1 in the female reproductive system are gradually getting explored. Within the ovarian micro-environment, the physiological expression of MALAT1 potentially modulates folliculogenesis while its upregulation promotes the metastasis of epithelial ovarian cancers. Interestingly, women with polycystic ovary syndrome have been shown to exhibit aberrant ovarian expression of MALAT1 and this is believed to contribute to the development of the disease. At the feto-maternal interface, MALAT1 potentially promotes trophoblast development. While its placental downregulation is linked to the pathogenesis of preeclampsia, its placental upregulation is associated with placenta increta and placenta percreta. Hence, abnormal expression of MALAT1 is a candidate molecular biomarker and therapeutic target for the treatment of these obstetric and gynecologic anomalies. To enhance a quick uncovering and detailed characterization of the mechanistic actions of MALAT1 in the female reproductive system, we have highlighted some knowledge deficits and have recommended ideal experimental models to be employed in prospective investigations.

Exosomal long non-coding RNA MALAT1: a candidate of liquid biopsy in monitoring of Wilms' tumor.

Wilms' tumor (WT) is a rare kidney cancer that primarily affects children. Exosomes are extracellular vesicles that cargo nucleic acids, proteins,etc. for cellular communication. Long non-coding RNAs (lncRNAs) have utility as biomarkers for cancer diagnosis, prognosis, and disease monitoring. We hypothesize that expression of lncRNA, metastasis-associated lung adenocarcinoma transcript-1(MALAT1), is dysregulated and possibly trafficked within exosomes to influence the tissue microenvironment for metastasis and recurrence of WT. We investigated the expression of MALAT1 in thirty WT samples by qPCR. Exosomes were isolated using a precipitated and affinity-binding-based kit, and characterized using TEM, NTA, and DLS. Mean number of exosomes was 9.01×108/mL in primary culture, 1.64×108/mL in urine, and 4.65×108/plasma:400µl. Average yield of total RNA was 1.28µg (primary-culture supernatant:1ml), 1.47µg (Urine:1ml), 1.65µg (Plasma:400 µL). We quantified MALAT1 in exosomes derived from these sources in patients of WT. Expression of MALAT1 was significantly downregulated (p=0.008) in WT samples. This is the first study that demonstrated the presence of lncRNA MALAT1 in various invasive and non-invasive samples of patients with WT(primary tissue culture, urine, and plasma samples).

MALAT-1 Is a Key Regulator of Epithelial-Mesenchymal Transition in Cancer: A Potential Therapeutic Target for Metastasis.

Metastasis-associated lung adenocarcinoma transcript-1 (MALAT-1) is a long intergenic non-coding RNA (lncRNA) located on chr11q13. It is overexpressed in several cancers and controls gene expression through chromatin modification, transcriptional regulation, and post-transcriptional regulation. Importantly, MALAT-1 stimulates cell proliferation, migration, and metastasis and serves a vital role in driving the epithelial-to-mesenchymal transition (EMT), subsequently acquiring cancer stem cell-like properties and developing drug resistance. MALAT-1 modulates EMT by interacting with various intracellular signaling pathways, notably the phosphoinositide 3-kinase (PI3K)/Akt and Wnt/β-catenin pathways. It also behaves like a sponge for microRNAs, preventing their interaction with target genes and promoting EMT. In addition, we have used bioinformatics online tools to highlight the disparities in the expression of MALAT-1 between normal and cancer samples using data from The Cancer Genome Atlas (TCGA). Furthermore, the intricate interplay of MALAT-1 with several essential targets of cancer progression and metastasis renders it a good candidate for therapeutic interventions. Several innovative approaches have been exploited to target MALAT-1, such as short hairpin RNAs (shRNAs), antisense oligonucleotides (ASOs), and natural products. This review emphasizes the interplay between MALAT-1 and EMT in modulating cancer metastasis, stemness, and chemoresistance in different cancers.

The interaction between MALAT1 and TUG1 with dietary fatty acid quality indices on visceral adiposity index and body adiposity index

We aimed to investigate the interaction between the transcript levels of taurine-upregulated gene 1 (TUG1) and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and the Cholesterol-Saturated Fat Index (CSI) in relation to the visceral adiposity index (VAI) and body adiposity index (BAI). This cross-sectional study involved 346 women classified as obese and overweight, aged between 18 and 48 years. Dietary intake and the quality of dietary fat were assessed using a validated and reliable 147-item semi-quantitative food frequency questionnaire, with the Cholesterol-Saturated Fat Index (CSI) used as an indicator. Transcription levels of MALAT1 and TUG1 were evaluated through real-time polymerase chain reaction following the criteria outlined in the Minimum Information for Publication of Quantitative standards. Serum profiles were measured using standard protocols. We observed a positive association between transcription level of MALAT1 and VAI in both crude (β = 3.646, 95% CI 1.950–5.341, p < 0.001) and adjusted (β = 8.338, 95% CI 6.110–10.566, p < 0.001) models. Furthermore, after adjusting for confounders, a significant positive interaction was noted between MALAT1 expression and CSI on BAI (β: 0.130, 95% CI 0.019, 0.240, p = 0.022), with a marginal positive interaction observed on VAI (β: 0.718, 95% CI − 0.028, 1.463, p = 0.059). It seems that there may be a positive interaction between MALAT1 transcription level and CSI on VAI and BAI among overweight and obese women. However, no associations were seen between TUG1 mRNA level and the above-mentioned outcomes. Further functional studies are still required to elucidate this concept.

LncRNA MALAT1 Expression Regulates Breast Cancer Progression via PI3K/AKT/mTOR Pathway Modulation.

Breast cancer is a significant health challenge for women globally, including the Pakistani population. Numerous pathways and small molecules like noncoding ribonucleotides are implicated in breast cancer development and progression. Among these, lncRNAs, have garnered considerable attention due to their role in breast cancer tumorigenesis and metastasis. In the current study involving 52 mammary tumor samples from the Pakistani population, the expression of lncRNA MALAT1 (metastasis associated lung adenocarcinoma transcript 1) was studied via RT-PCR (Real-Time polymerase chain reaction). In addition, PI3K/AKT/mTOR pathway expression was also assessed through RT-PCR and immunohistochemistry in breast cancer patient samples. The study also investigated the cross-talk of lncRNA MALAT1 and PI3K pathway genes by inhibiting it with PI3K inhibitor (LY294002) in MDA-MB-231 cell line. Furthermore, lncRNA MALAT1 was silenced in MDA-MB-231 cells using siRNA to determine its impact on breast cancer proliferation and metastasis. The results revealed an upregulated expression of MALAT1 and PI3K/AKT/mTOR pathway genes in grade II and III breast tissue samples before chemotherapy. The proliferation, growth, and invasion of breast cancer cells were significantly reduced upon MALAT1 silencing in MDA-MB-231. Further, its downregulation substantially reduced the PI3K pathway expression levels at mRNA and protein levels. In conclusion, the current study suggests that MALAT1 could serve as a therapeutic target for breast cancer, underscoring its role in breast cancer proliferation and metastasis. Moreover, the study proposes a mechanism of action of MALAT1, demonstrating that its inhibition can reduce the expression of the PI3K/AKT/mTOR axis. These findings emphasize the potential significance of targeting MALAT1 as a therapeutic strategy for breast cancer, and further exploration of this interaction is warranted to gain deeper insight into the molecular mechanism of this lncRNA.

MALAT1: A novel hypothesis on the pathology of vascular injury in patients with β-thalassemia

Vascular injury is a common consequence in β-thalassemia patients with severe anemia. Vascular cell damage can result in cardiomyopathy, thrombosis, and persistent ulceration. Although it has been suggested that injury is caused by iron accumulation and oxidative stress, the exact molecular mechanism remains unknown. Here, we highlight the potential role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in this pathophysiology. This hypothesis is based on the literature, which demonstrates that lncRNA expression of MALAT1-lncRNA is linked to vascular damage, wound healing capability, and cardiomyopathy. Furthermore, various technologies can be employed to manipulate the expression of MALAT1-lncRNA. In light of these studies, assessment of MALAT1 expression may enhance our understanding of the molecular pathophysiology of vascular damage in β-thalassemia. If confirmed, elevated MALAT1 expression could serve as a promising target for expediting the healing process in pathogenic tissues. Additionally, MALAT1 may serve as a surrogate biomarker for therapeutic management of patients with β-thalassemia who have vascular complications.

Long noncoding RNA MALAT1; A novel and potential therapeutic target for Alzheimer’s disease

AbstractBackgroundAlzheimer disease (AD) is the most common form of dementia, characterized pathologically by amyloid plaques and neurofibrillary tangles. Despite considerable advances in the knowledge of AD pathogenesis, we know little about preventing or delaying the ongoing neurodegenerative process, indicating that there remain critical gaps in our understanding of disease mechanisms and opportunities for new treatment approaches. Long noncoding RNAs (lncRNAs) are larger than 200 nucleotides, structurally resemble mRNAs but do not encode proteins. LncRNAs participate in regulation of several physiological and pathophysiological processes by modulating gene expression and have been documented in several neurodegenerative diseases. Among them, metastasis associated lung adenocarcinoma transcript 1 (MALAT1) is a highly abundant and evolutionary conserved lncRNA and regulates a subset of genes involved in synaptic plasticity, cognitive function and memory.MethodTo test the hypothesis that lncRNA MALAT1 plays an important role in AD pathology, we quantified expression levels of lncRNA MALAT1 in the brains of age‐matched AD patients and cognitively normal controls (Non‐AD) by QRT‐PCR and RNAScope in situ hybridization assays, respectively. We further examined the lncRNA MALAT1 expressions and AD‐related neuropathology in the brains of 5XFAD transgenic mouse model of AD and their WT littermates using dual RNAScope/Immunofluorescence technique.ResultWe observed reduced expressions of lncRNA MALAT1 in the hippocampus of AD brains compared to the non‐AD control brains. Next, we found marked reduced expression of lncRNA MALAT1 in the brain of 5xFAD mice compared to non‐transgenic mice. Interestingly, decreased expression levels of lncRNA MALAT1 are correlated with AD‐related neuropathology and memory deficits in 5xFAD mice.ConclusionThese findings provided compelling evidence that AD is associated with altered expression of lncRNA MALAT1 which may influence several pathways related to neural damage and memory deficits in AD. Because expression patterns, interacting proteins, pathways, and biological functions of lncRNA MALAT1 are remain largely unexplored in AD, understanding how lncRNA MALAT1 regulates AD‐related neuropathology may allow development of effective therapies for this incurable disease.

The Long non-coding RNA MALAT1 functions as a competing endogenous RNA to regulate vascular remodeling by sponging miR-145-5p/HK2 in hypertension

ABSTRACT Long non-coding RNAs (LncRNAs) have been found to play a regulatory role in the pathophysiology of vascular remodeling-associated illnesses through the lncRNA-microRNA (miRNA) regulation axis. LncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is thought to be involved in proliferation, migration, apoptosis, and calcification of vascular smooth muscle cells (VSMCs). The purpose of this study was to investigate the regulatory role of MALAT1 on vascular remodeling in hypertension. Our data indicate that the expression of MALAT1 is significantly upregulated in hypertensive aortic smooth muscle. Knockdown of MALAT1 inhibited the proliferation, migration, and phenotypic transition of VSMCs induced by Ang II. Bioinformatics analysis was used to predict the complementary binding of miR-145-5p to the 3’-untranslated region of MALAT1. Besides, the expressions of MALAT1 and miR-145-5p were negatively correlated, while luciferase reporter assays and RNA immunoprecipitation assay validated the interaction between miR-145-5p and MALAT1. The proliferation, migration and phenotypic transformation of VSMCs induced by overexpression of MALAT1 were reversed in the presence of miR-145-5p. Furthermore, we verified that miR-145-5p could directly target and bind to hexokinase 2 (HK2) mRNA, and that HK2 expression was negatively correlated with miR-145-5p in VSMCs. Knockdown of HK2 significantly inhibited the effects of overexpression of MALAT1 on Ang II-induced VSMCs proliferation, migration and phenotypic transformation. Taken together, the MALAT1/miR-145-5p/HK2 axis may play a critical regulatory role in the vascular remodeling of VSMCs in hypertension.

Stem cell therapy with CRISPR/Cas9-mediated MALAT1 delivery modulates miR-142 and rescues wound healing in rats with age-associated diabetic foot ulcers

BackgroundDiabetic foot ulcer (DFU) is a serious diabetes complication, significantly impacting the quality of life, particularly in the elderly. Age-associated DFUs pose additional challenges due to impaired healing mechanisms. Our study aims to explore the role of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) as a miR-142 sponge in repairing diabetic rat foot ulcer tissue under age-associated diabetes, offering a new theoretical basis and therapeutic target for preventing and treating diabetic vascular disease in the elderly. MethodsUsing qPCR, we analyzed MALAT1 and miR-142 expression in EPCs and hUC-MSCs. Targetscan predicted potential interaction targets for MALAT1 and miR-142, confirmed by dual luciferase reporter gene assay. An age-associated diabetic rat model was established using Streptozotocin (STZ) injection. Hypoxia, apoptosis, and angiogenesis-related proteins were assessed through Western Blot. In vitro, miR-142 inhibition and MALAT1 overexpression promoted foot ulcer healing in diabetic rats. ResultsMALAT1 acted as a miR-142 sponge, downregulated in hUC-MSCs under high glucose, relevant to age-associated diabetic foot ulcers. MiR-142 negatively regulated SIRT1 and Nrf2. In vitro experiments demonstrated potential significance for age-related DFU treatment. ConclusionsMALAT1 in human umbilical cord mesenchymal stem cells expedited foot ulcer healing in diabetic rats, particularly in age-associated diabetes, through miR-142 sponge activity. These findings offer insights for novel therapeutic strategies targeting elderly diabetic foot ulcers, emphasizing exogenous stem cell transplantation's potential in effective DFU treatment for the elderly.

Expression Analysis of Long Noncoding RNA-MALAT1 and Interleukin-6 in Inflammatory Bowel Disease Patients.

Inflammatory bowel disease (IBD) manifests as chronic inflammation within the gastrointestinal tract. The study focuses on a long noncoding RNA (lncRNA) known as Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1). MALAT1's misregulation has been linked with various autoimmune diseases and regulates proinflammatory cytokines. The role of IL6 in immune-triggered conditions, including IBD, is another focal point. In this research, the expression of MALAT1 and IL6 in IBD patients was meticulously analyzed to uncover potential interactions. The study involved 33 IBD patients (13 with Crohn's disease and 20 with ulcerative colitis) and 20 healthy counterparts. Quantitative real-time polymerase chain reaction determined the MALAT1 and IL6 gene expression levels. The competitive endogenous RNA (ceRNA) regulatory network was constructed using several tools, including LncRRIsearch and Cytoscape. A deep dive into the Inflammatory Bowel Disease database was undertaken to understand IL6's role in IBD. Drugs potentially targeting these genes were also pinpointed using DGIdb. Results indicated a notable elevation in the expression levels of MALAT1 and IL6 in IBD patients versus healthy controls. MALAT1 and IL6 did not show a direct linear correlation, but IL6could serve as MALAT1's target. Analyses unveiled interactions between MALAT1 and IL6, regulated by hsa-miR-202-3p, hsa-miR-1-3p, and has-miR-9-5p. IL6's pivotal role in IBD-associated inflammation, likely interacting with other cytokines, was accentuated. Moreover, potential drugs like CILOBRADINE for MALAT1 and SILTUXIMAB for IL6 were identified. This research underscored MALAT1 and IL6's potential value as targets in diagnosis and treatment for IBD patients.

METTL3 Mediated MALAT1 m6A Modification Promotes Proliferation and Metastasis in Osteosarcoma Cells.

As one of the most ubiquitous types of posttranscriptional modification, N6-methyladenosine (m6A) is extensively implicated in almost all types of cancers, including osteosarcoma. Our previous research partially uncovered the role of Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) in osteosarcoma. However, the relationships between methyltransferase-like 3 (METTL3) and noncoding RNAs modified by METTL3, especially MALAT1, in osteosarcoma remain obscure. The expression of METTL3 in osteosarcoma was evaluated by online bioinformatics analysis, immunohistochemical (IHC) staining, western blotting (WB), and reverse transcription-quantitative PCR (RT‒qPCR). Cell Counting Kit 8 (CCK-8) and Transwell assays were used to evaluate the cell proliferation and invasion abilities. The expression of MALAT1 in osteosarcoma was evaluated by online bioinformatics analysis and RT‒qPCR analysis. m6A methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) was used to detect m6A modification changes in MALAT1. An actinomycin D assay was used to study changes in the stability of MALAT1. METTL3 was upregulated in osteosarcoma tissues and cell lines. Functionally, METTL3 promoted the proliferation and migration of osteosarcoma cells. Moreover, a clear positive correlation was found between METTL3 and MALAT1 expression, and MALAT1 was upregulated in osteosarcoma tissues and cells. Mechanistically, the presence of m6A modification sites in MALAT1 and METTL3-mediated m6A modification increased the stability of MALAT1 in osteosarcoma cells and promoted their proliferation and migration. In this study, it was concluded that in osteosarcoma cells, METTL3, acting as an oncogene, promoted m6A modification of MALAT1, increased the stability of MALAT, and enhanced MALAT1-mediated oncogenic function.

MALAT1 promotes FOXA1 degradation by competitively binding to miR-216a-5p and enhancing neuroendocrine differentiation in prostate cancer

ObjectivesProstate cancer (PC) is a leading cause of cancer-related death in males worldwide. Neuroendocrine differentiation (NED) is a feature of PC that often goes undetected and is associated with poor patient outcomes. Long non-coding RNAs (lncRNAs), microRNAs (miRNAs/miRs), and messenger RNAs (mRNAs) play important roles in the development and progression of PC. MethodsIn this study, we used transcriptome sequencing and bioinformatics analysis to identify key regulators of NED in PC. Specifically, we examined the expression of PC-related lncRNAs, miRNAs, and mRNAs in PC cells and correlated these findings with NED phenotypes. ResultsOur data revealed that metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and zinc finger protein 91 (ZFP91) were upregulated in PC, while miR-216a-5p was down-regulated. Ectopic expression of MALAT1 induced NED and promoted malignant phenotypes of PC cells. Furthermore, we found that MALAT1 competitively bound to miR-216a-5p, upregulated ZFP91, and promoted the degradation of forkhead box A1 (FOXA1), a key gene involved in NED of PC. ConclusionTaken together, these results suggest that MALAT1 plays an oncogenic role in NED and metastasis of PC via the miR-216a-5p/ZFP91/FOXA1 pathway. Our study highlights the potential of targeting this pathway as a novel therapeutic strategy for PC.

The ATF4-regulated LncRNA MALAT1 promotes odontoblastic differentiation of human dental pulp stem cells via histone demethylase JMJD3: An in vitro study.

This study aimed to investigate the upstream regulators and specific mechanisms of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the odontoblastic differentiation of human dental pulp stem cells (hDPSCs). Human dental pulp stem cells were isolated and cultured, followed by conducting loss- or gain-of-function experiments on ATF4 and loss experiments on MALAT1 to elucidate their respective biological functions in odontoblastic differentiation. Chromatin immunoprecipitation assays and RNA immunoprecipitation were performed to uncover the interaction between ATF4-MALAT1 and MALAT1-JMJD3, respectively. The odontoblastic differentiation was estimated by the mRNA and protein of DSPP and DMP1, as well as alkaline phosphatase staining. Expression of MALAT1 was upregulated in the hDPSCs cultured in an odontoblastic medium, and MALAT1 downregulation suppressed the odontoblastic differentiation of the hDPSCs. Subsequent experiments confirmed that ATF4 promoted odontoblastic differentiation and induced MALAT1 expression by binding to the MALAT1 promoter region. Further experiments revealed that nuclear MALAT1 interacted with JMJD3. MALAT1 knockdown decreased the JMJD3 protein level and demethylase activity, and it enhanced H3K27me3 occupancy of the promoter region of DSPP and DMP1, resulting in the inhibition of DSPP and DMP1 transcription. Importantly, JMJD3 overexpression significantly attenuated the inhibition of odontoblastic differentiation induced by MALAT1 knockdown. ATF4-regulated MALAT1 plays a positive regulatory role in odontoblastic differentiation of hDPSCs through JMJD3-mediated H3K27me3 modifications of the DSPP and DMP1 promoters.

Anti-apoptotic capacity of MALAT1 on hippocampal neurons correlates with CASP3 DNA methylation in a mouse model of autism.

Prior evidence has suggested the alleviatory effect of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) on neuroinflammation in neurodegenerative diseases. This study primarily investigates the underlying mechanism of how the long non-coding RNA MALAT1 affects neuronal apoptosis in the hippocampus of mice with autism spectrum disorder (ASD). The findings demonstrate that CASP3 is highly expressed while MALAT1 is downregulated in the hippocampal neurons of autistic mice. MALAT1 mainly localizes within the cell nucleus and recruits DNA methyltransferases (including DNMT1, DNMT3a, and DNMT3b) to the promoter region of CASP3, promoting its methylation and further inhibiting its expression. In vitro experiments reveal that reducing MALAT1 expression promotes the expression of CASP3 and Bax while suppressing Bcl-2 expression, thereby enhancing cellular apoptosis. Conversely, increasing MALAT1 expression yields the opposite effect. Consequently, these results further confirm the role of MALAT1 in suppressing neuronal apoptosis in the hippocampus of mice with ASD through the regulation of CASP3 promoter methylation. Thus, this research unveils the significant roles of MALAT1 and CASP3 in the pathogenesis of ASD, offering new possibilities for future therapeutic interventions.