MALAT1 long non-coding RNA and breast cancer

LncRNA MALAT1 Regulating Lung Carcinoma Progression via the miR-491-5p/UBE2C Axis

Long noncoding RNAs (lncRNAs) play a critical role in the development of lung carcinoma. The mechanism of MALAT1 in lung carcinoma development is not understood very well. This study aimed to investigate the role of MALAT1 in lung carcinoma progression and the mechanism underlying the role of miR-491-5p in the MALAT1 mediated regulation of UBE2C expression. The results indicated that the expression of MALAT1 was often augmented in lung carcinoma cells. Suppression of MALAT1 blocked the proliferation, invasion and migration ability of cancer cells and inhibited the expression of UBE2C. UBE2C restoration attenuated the MALAT1 knockdown-induced anti-cancer effects. Moreover, UBE2C and MALAT1 were indicated as targets of miR-491-5p and inhibition of miR-491-5p restored the MALAT1 knockdown-induced inhibition of the progression of lung carcinoma. Furthermore, MALAT1 sponged miR-491-5p to upregulate UBE2C expression, causing it to act as a competing endogenous RNA. Collectively, MALAT1 downregulation suppressed lung carcinoma progression by regulating the miR-491-5p/UBE2C axis. These results indicate that MALAT1 could be a molecular target for lung carcinoma treatment and prognosis.

Understanding the function of the tumor microenvironment, and compounds from marine organisms for breast cancer therapy

The pathology and physiology of breast cancer (BC), including metastasis, and drug resistance, is driven by multiple signaling pathways in the tumor microenvironment (TME), which hamper antitumor immunity. Recently, long non-coding RNAs have been reported to mediate pathophysiological develop-ments such as metastasis as well as immune suppression within the TME. Given the complex biology of BC, novel personalized therapeutic strategies that address its diverse pathophysiologies are needed to improve clinical outcomes. In this review, we describe the advances in the biology of breast neoplasia, including cellular and molecular biology, heterogeneity, and TME. We review the role of novel molecules such as long non-coding RNAs in the pathophysiology of BC. Finally, we provide an up-to-date overview of anticancer compounds extracted from marine microorganisms, crustaceans, and fishes and their synergistic effects in combination with other anticancer drugs. Marine compounds are a new discipline of research in BC and offer a wide range of anti-cancer effects that could be harnessed to target the various pathways involved in BC development, thus assisting current therapeutic regimens.

Downregulation of circ-RANBP9 in laryngeal cancer and its clinical significance

Background

Laryngeal cancer (LC) is a common malignant tumor of the head and neck. As circular RNAs (circRNAs) and other non-coding RNAs are involved in various malignant processes, we analyzed circRNAs to better understand LC and explored specific tumor markers.

Methods

High-throughput sequence was performed to analyze the differential circular RNAs in four coupled laryngeal cancers and para-cancerous tissues. The differential expression of selected circ-RANBP9 in laryngeal cancer tissues and cells was verified by RT-qPCR assay. CCK8, EDU, Transwell and wound healing assays were used to confirm the biological function of circ-RANBP9 in laryngeal cancer. Western blot assay was performed to identify the effects of circ-RANBP9 having on the epithelial to mesenchymal transition process. One-way AN0VA was used to analyze the correlation between the expression of circ-RANBP9 and clinicopathological parameters of the included patients. Kaplan-Meier analysis was used to investigate whether the expression level of circ-RANBP9 correlated with survival in LC patients. Bioinformatic analyses were also conducted to predict the functions and possible signaling pathways of the targeted mRNAs of circ-RANBP9 via co-expression and competing endogenous RNA network.

Results

We found a transcript from RNA sequence data, termed hsa_circ_0001578, which is a circRNA spliced from RANBP9. Circ-RANBP9 was downregulated in the LC cell lines tissues, relating to a better prognosis. Circ-RANBP9 was found to inhibit the proliferation, migration, and invasion ability of LC, exerting a suppressive role in the epithelial to mesenchymal transition process as well. For the diagnostic value of circ-RANBP9, the sensitivity and the specificity were 0.979 and 0.553, respectively. Circ-RANBP9 downregulation was significantly correlated with differentiation (P=0.031), T-stage (P=0.018), lymphatic metastasis (P=0.046), and clinical stage (P=0.003). Circ-RANBP9 was involved in insulin-like growth factor receptor binding, cell polarity, focal adhesion, and MAPK signaling pathways. CeRNA analysis identified the possible involvement of circ-RANBP9 in the ECM-receptor interaction, cAMP, calcium, and Wnt signaling pathways by harboring miRNA genes.

Conclusions

Circ-RANBP9 was confirmed to play important roles in inhibiting laryngeal cancers. Circ-RANBP9 was also validated to be associated with the clinicopathological parameters and diagnostic value, suggesting that circ-RANBP9 is a promising biomarker for LC prognosis and early diagnosis.

Role of MALAT1 in gynecological cancers: Pathologic and therapeutic aspects

Gynecological cancers, including breast, ovarian, uterine, vaginal, cervical and vulvar cancers are among the major threats to modern life, particularly to female health. Long non-coding RNAs (lncRNAs) play critical roles in normal development of organisms, as well as the tumorigenesis process, and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a large infrequently spliced lncRNA, which have been implicated in different gynecological cancers. MALAT1 is overexpressed in breast, ovarian, cervical and endometrial cancers, which initiates cancer progression by inducing changes in the expression of several anti-apoptotic and epithelial-to-mesenchymal transition-related genes. Targeting MALAT1 is an important strategy to combat gynecological cancers, and application of RNA-interference technology and chemotherapeutic process are crucial to target and minimize MALAT1 activity. The present review discusses the role of MALAT1 in gynecological cancers, and potential strategies to target this lncRNA to develop cancer therapeutics. However, further clinical studies are required to determine the prognostic potential of MALAT1 in gynecological cancers.

Bone Marrow Mesenchymal Stem Cells-Derived Extracellular Vesicles Promote Proliferation, Invasion and Migration of Osteosarcoma Cells via the lncRNA MALAT1/miR-143/NRSN2/Wnt/β-Catenin Axis

INTRODUCTION

Osteosarcoma is a malignant primary bone tumor. Bone marrow-derived mesenchymal stem cells-derived extracellular vesicles (BMSC-EVs) bear repair function for bone and cartilage. This study investigated the mechanism of BMSC-EVs in osteosarcoma cell proliferation, migration and invasion.

METHODS

BMSC-EVs were isolated and identified. The effects of different concentrations of EVs on osteosarcoma cell proliferation, migration and invasion were evaluated. LncRNA MALAT1 expression in osteosarcoma cells was detected. BMSCs were transfected with si-MALAT1 or si-NC. The binding relationships between MALAT1 and miR-143, and miR-143 and NRSN2 were verified. Levels of NRSN2 and Wnt/β-catenin pathway key proteins were detected. miR-143 mimic was transfected into EVs-treated osteosarcoma cells. Nude mice were injected with MG63 cells to verify the effect of EVs on osteosarcoma growth in vivo.

RESULTS

BMSC-EVs facilitated proliferation, invasion and migration of osteosarcoma cells. BMSC-EVs carried MALAT1 into osteosarcoma cells. BMSC-EVs-treated osteosarcoma cells showed increased MALAT1 and NRSN2 expressions, decreased miR-143 expression, and activated Wnt/β-catenin pathway. miR-143 mimic or si-MALAT1 reversed the effects of BMSC-EVs on osteosarcoma cells. In vivo experiment confirmed that BMSC-EVs promoted tumor growth in nude mice.

DISCUSSION

BMSC-EVs promoted proliferation, invasion and migration of osteosarcoma cells via the MALAT1/miR-143/NRSN2/Wnt/β-catenin axis. This study might offer new insights into osteosarcoma management.

Long Non-Coding RNA TRIM52-AS1 Promotes Growth and Metastasis via miR-218-5p/ROBO1 in Hepatocellular Carcinoma

Background

Hepatocellular carcinoma (HCC) is a malignant disease with a high mortality among primary HCC patients worldwide. Lots of studies have shown that lncRNAs are known as the biomarkers in diagnosis, treatment and prognosis of hepatocellular carcinoma. Therefore, clarifying the detailed function and mechanism of the lncRNA in the HCC progressing seems particularly important.

Methods

The TCGA and GEO database and RT-qPCR were used to analyse the expression of TRIM52-AS1 in HCC tissues and cell lines. Clinical data were collected to further analyze the correlation between indicators of clinical samples and the expression of TRIM52-AS1. CCK-8, plate clone and transwell assays were employed to evaluate the role of TRIM52-AS1 on cell proliferation, migration and invasion. Then, bioinformatics prediction, luciferase reporter, RNA immunoprecipitation (RIP), and RT-qPCR were employed to analyze the direct interaction among TRIM52-AS1, miR-218-5p and ROBO1. Additionally, the rescue function assays were used to verify that miR-218-5p/ROBO1 was the function downstream of TRIM52-AS1.

Results

TRIM52-AS1 was overexpressed in HCC according to the TCGA database and RT-qPCR assay. The expression of TRIM52-AS1 was higher in the metastatic foci compared with primary tumor according to the GEO database. Additionally, TRIM52-AS1 knockdown inhibited the proliferation and metastasis of HCC cells. TRIM52-AS1 could act as competitive endogenous RNA to regulate ROBO1 through miR-218-5p, then promoted the HCC cell progression.

Conclusion

TRIM52-AS1 is overexpressed in HCC and can promote the proliferation and metastasis of HCC cells through miR-218-5p/ROBO1 axis, then drives the HCC cell progression.

lncRNAs in development and differentiation: from sequence motifs to functional characterization

The number of long noncoding RNAs (lncRNAs) with characterized developmental and cellular functions continues to increase, but our understanding of the molecular mechanisms underlying lncRNA functions, and how they are dictated by RNA sequences, remains limited. Relatively short, conserved sequence motifs embedded in lncRNA transcripts are often important determinants of lncRNA localization, stability and interactions. Identifying such RNA motifs remains challenging due to the substantial length of lncRNA transcripts and the rapid evolutionary turnover of lncRNA sequences. Nevertheless, the recent discovery of specific RNA elements, together with their experimental interrogation, has enabled the first step in classifying heterogeneous lncRNAs into sub-groups with similar molecular mechanisms and functions. In this Review, we focus on lncRNAs with roles in development, cell differentiation and normal physiology in vertebrates, and we discuss the sequence elements defining their functions. We also summarize progress on the discovery of regulatory RNA sequence elements, as well as their molecular functions and interaction partners.

MaTAR25 lncRNA regulates the Tensin1 gene to impact breast cancer progression

Misregulation of long non-coding RNA (lncRNA) genes has been linked to a wide variety of cancer types. Here we report on Mammary Tumor Associated RNA 25 (MaTAR25), a nuclear enriched and chromatin associated lncRNA that plays a role in mammary tumor cell proliferation, migration, and invasion, both in vitro and in vivo. MaTAR25 functions by interacting with purine rich element binding protein B (PURB), and associating with a major downstream target gene Tensin1 (Tns1) to regulate its expression in trans. The Tns1 protein product is a critical component of focal adhesions linking signaling between the extracellular matrix and the actin cytoskeleton. Knockout of MaTAR25 results in down-regulation of Tns1 leading to a reorganization of the actin cytoskeleton, and a reduction of focal adhesions and microvilli. We identify LINC01271 as the human ortholog of MaTAR25, and importantly, increased expression of LINC01271 is associated with poor patient prognosis and metastasis. Our findings demonstrate that LINC01271 represents a potential therapeutic target to alter breast cancer progression.

Roles and Mechanisms of the Long Noncoding RNAs in Cervical Cancer

Cervical cancer (CC) continues to be one of the leading causes of death for women across the world. Although it has been determined that papillomavirus infection is one of the main causes of the etiology of the disease, genetic and epigenetic factors are also required for its progression. Among the epigenetic factors are included the long noncoding RNAs (lncRNAs), transcripts of more than 200 nucleotides (nt) that generally do not code for proteins and have been associated with diverse functions such as the regulation of transcription, translation, RNA metabolism, as well as stem cell maintenance and differentiation, cell autophagy and apoptosis. Recently, studies have begun to characterize the aberrant regulation of lncRNAs in CC cells and tissues, including Homeobox transcript antisense RNA (HOTAIR), H19, Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), Cervical Carcinoma High-Expressed 1 (CCHE1), Antisense noncoding RNA in the inhibitors of cyclin-dependent kinase 4 (ANRIL), Growth arrest special 5 (GAS5) and Plasmacytoma variant translocation 1 (PVT1). They have been associated with several disease-related processes such as cell growth, cell proliferation, cell survival, metastasis and invasion as well as therapeutic resistance, and are novel potential biomarkers for diagnosis and prognosis in CC. In this review, we summarize the current literature regarding the knowledge we have about the roles and mechanisms of the lncRNAs in cervical neoplasia.

Identification and characterization of functional long noncoding RNAs in cancer

Long noncoding RNAs (lncRNAs) have emerged as key regulators in a variety of cellular processes that influence disease states. In particular, many lncRNAs are genetically or epigenetically deregulated in cancer. However, whether lncRNA alterations are passengers acquired during cancer progression or can act as tumorigenic drivers is a topic of ongoing investigation. In this review, we examine the current methodologies underlying the identification of cancer-associated lncRNAs and highlight important considerations for evaluating their biological significance as cancer drivers.

Long Non-coding RNAs in Cancer: Implications for Diagnosis, Prognosis, and Therapy

Long non-coding RNAs (lncRNAs) are major components of cellular transcripts that are arising as important players in various biological pathways. They have received extensive attention in recent years, regarded to be involved in both developmental processes and various diseases. Due to their specific expression and functional diversity in a variety of cancers, lncRNAs have promising applications in cancer diagnosis, prognosis and therapy. Studies have shown that lncRNAs with high specificity and accuracy have the potential to become biomarkers in cancers. LncRNAs can be noninvasively extracted from body fluids, tissues and cells, and can be used as independent or auxiliary biomarkers to improve the accuracy of diagnosis or prognosis. Currently, the most well-recognized lncRNA is PCA3, which has been approved for use in the diagnosis of prostate cancer. Moreover, the underlying mechanisms of lncRNAs were explored as therapeutic targets, which have been investigated in clinical trials of several cancers. In this review, we presented a compilation of recent publications, clinical trials and patents, addressing the potential of lncRNAs that could be considered as biomarkers or therapeutic targets, with the hopes of providing promised implications for future cancer therapy.

Upregulated Long Non-Coding RNA LL22NC03-N64E9.1 Promotes the Proliferation and Migration of Human Breast Cancer Cells by Silencing Kruppel-Like Factor 2 Expression

Introduction

Recently, the significant regulatory effects of lncRNAs on the oncogenesis and growth of tumor have been demonstrated by an increasing number of research projects. A previous study showed that LL22NC03-N64E9.1 could promote the development of colorectal cancer, especially via enhanced cell proliferation. Similarly, this lncRNA should have comparable functions in breast cancer (BC), which requires in-depth investigation. Therefore, this study was designed to explore the correlation of LL22NC03-N64E9.1 with BC.

Methods

qRT-PCR was used to assess the relative expression of LL22NC03-N64E9.1 in BC tissues. Cell viability examination and colony formation experiments were performed to investigate the role of LL22NC03-N64E9.1 in BC cell’s proliferation. Transwell assays were used to explore the effects of LL22NC03-N64E9.1 on BC cell’s migration. RNA immunoprecipitation, chromosome immunoprecipitation assay and rescue experiments were performed to analyze the association of LL22NC03-N64E9.1 with target proteins and genes in BC cells.

Results

We identified that LL22NC03-N64E9.1 is an oncogene, upregulated in BC, which was verified in a cohort of 48 pairs of BC tissues. Based on the loss-of-function experiments, silencing LL22NC03-N64E9.1 expression significantly inhibited malignancy progression. In terms of the mechanism, LL22NC03-N64E9.1 acted on the enhancer of zeste homolog 2 (EZH2) by direct binding, which promoted BC cell growth. Furthermore, in the promoters of KLF2, the trimethylation of H3K27 could be regulated by LL22NC03-N64E9.1 as the mediator.

Conclusion

Relying on the LL22NC03-N64E9.1/EZH2/KLF2 pathway, the lncRNA LL22NC03-N64E9.1 was significantly associated with BC development and could, therefore, be a potential therapeutic target to block BC growth.

Expression of TRPC1 and SBEM protein in breast cancer tissue and its relationship with clinicopathological features and prognosis of patients

This study investigated the relationship of the expression of transient receptor potential channel 1 (TRPC1), small breast epithelial mucin (SBEM) in breast cancer tissues with clinical pathological features and prognosis of patients. Altogether 50 patients with breast cancer who were treated in Weifang People's hospital from April 2017 to November 2018 were selected, and the mRNA and protein differences of TRPC1 and SBEM in breast cancer patients and normal breast cancer tissues were detected by qRT-PCR and Western blot. Spearman test was used for correlation analysis. Logistic univariate and multivariate analysis were performed on the risk factors related to breast cancer metastasis in breast cancer patients. The expression of TRPC1 and SBEM in breast cancer tissues was significantly higher than that in normal breast tissues (P<0.001). The mRNA expression of TRPC1, SBEM and protein was not related to age, tumor size and tissue grade of breast cancer patients, but related to TNM stage, clinical stage and lymph node metastasis (P<0.001). The relative expression of TRPC1 was positively correlated with clinical stage of breast cancer (r=0.992, P<0.001). The relative expression of SBEM was positively correlated with the clinical stage of breast cancer (r=0.853, P<0.001). The relative expression of TRPC1 was positively correlated with TNM staging of breast cancer (r=0.860, P<0.001). The relative expression of SBEM was positively correlated with TNM staging of breast cancer (r=0.880, P<0.001). Multivariate conditional Logistic regression analysis showed that TNM staging, TRPC1, SBEM were independent risk factors for malignant breast cancer metastasis. On the contrary, expression of TRPC1 and SBEM in breast cancer tissues was up-regulated. TRPC1 and SBEM may be involved in the process of breast cancer occurrence, development and metastasis, and can be used as potential tissue biomarkers in diagnosis of breast cancer metastasis and disease assessment.

Association of circulating long non-coding RNA MALAT1 in diagnosis, disease surveillance, and prognosis of acute ischemic stroke

We aimed to investigate the association of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1) with acute ischemic stroke (AIS), and its association with disease severity, inflammation, and recurrence-free survival (RFS) in AIS patients. One hundred and twenty AIS patients and 120 controls were recruited. Venous blood samples from AIS patients (within 24 h after symptoms onset) and controls (at entry to study) were collected to detect plasma lnc-MALAT1 expression by real-time quantitative polymerase chain reaction. AIS severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) score. Plasma concentrations of inflammation factors (including C-reactive protein (CRP), tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-8, IL-10, IL-17, and IL-22) were measured and RFS was calculated. lnc-MALAT1 expression was decreased in AIS patients compared to controls, and it had a close correlation with AIS (AUC=0.791, 95% CI: 0.735-0.846). For disease condition, lnc-MALAT1 expression negatively correlated with NIHSS score and pro-inflammatory factor expression (including CRP, TNF-α, IL-6, IL-8, and IL-22), while it positively correlated with anti-inflammatory factor IL-10 expression. Furthermore, lnc-MALAT1 expression was elevated in AIS patients with diabetes. For prognosis, no statistical correlation of lnc-MALAT1 expression with RFS was found, while a trend for longer RFS was observed in patients with lnc-MALAT1 high expression compared to those with lnc-MALAT1 low expression.

TGF-β1-Induced Upregulation of MALAT1 Promotes Kazakh's Esophageal Squamous Cell Carcinoma Invasion by EMT

Transforming growth factor β1 (TGF-β1) plays an important role in tumor initiation and development by inducing epithelial-mesenchymal Transition (EMT). Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is a long noncoding RNA (lncRNA) that contributes to the invasion and metastasis of tumors, including esophageal squamous cell carcinoma (ESCC). The aim of the present study was to explore the underlying mechanisms implicated in EMT and to clarify whether TGF-β1 regulates MALAT1 expression, thereby promoting the invasion of ESCC. Expression of TGF-β1, MALAT1 and EMT-related markers, including E-cadherin and Vimentin, was detected in clinical samples of Kazakh's ESCC. The role of TGF-β1 in the regulation of MALAT1 in ESCC invasion was evaluated at the ESCC cell line level. High TGF-β1 expression was significantly associated with poor survival among patients with Kazakh's ESCC. Additionally, the expression of Vimentin was upregulated, and the expression of E-cadherin was downregulated and varied. The expression of MALAT1 positively correlated with the expression of TGF-β1 both in vivo and in vitro. Furthermore, knockdown of MALAT1 inhibited TGF-β1-induced EMT. Our data indicate that MALAT1 is heavily involved in EMT induced by TGF-β1. MALAT1 may be a therapeutic target in the suppression of metastasis and invasion of ESCC.

The roles of long noncoding RNAs in breast cancer metastasis

Breast cancer is the most significant threat to female health. Breast cancer metastasis is the major cause of mortality in breast cancer patients. To fully unravel the molecular mechanisms that underlie the breast cancer cell metastasis is critical for developing strategies to improve survival and prognosis in breast cancer patients. Recent studies have revealed that the long noncoding RNAs (lncRNAs) are involved in breast cancer metastasis through a variety of molecule mechanisms, though the precise functional details of these lncRNAs are yet to be clarified. In the present review, we focus on the functions of lncRNAs in breast cancer invasion and metastasis, with particular emphasis on the functional properties, the regulatory factors, the therapeutic promise, as well as the future challenges in studying these lncRNA.

Regulation of MALAT1 triple helix stability and in vitro degradation by diphenylfurans

Small molecule-based modulation of a triple helix in the long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been proposed as an attractive avenue for cancer treatment and a model system for understanding small molecule:RNA recognition. To elucidate fundamental recognition principles and structure-function relationships, we designed and synthesized nine novel analogs of a diphenylfuran-based small molecule DPFp8, a previously identified lead binder of MALAT1. We investigated the role of recognition modalities in binding and in silico studies along with the relationship between affinity, stability and in vitro enzymatic degradation of the triple helix. Specifically, molecular docking studies identified patterns driving affinity and selectivity, including limited ligand flexibility, as observed by ligand preorganization and 3D shape complementarity for the binding pocket. The use of differential scanning fluorimetry allowed rapid evaluation of ligand-induced thermal stabilization of the triple helix, which correlated with decreased in vitro degradation of this structure by the RNase R exonuclease. The magnitude of stabilization was related to binding mode and selectivity between the triple helix and its precursor stem loop structure. Together, this work demonstrates the value of scaffold-based libraries in revealing recognition principles and of raising broadly applicable strategies, including functional assays, for small molecule-RNA targeting.

Unleash multifunctional role of long noncoding RNAs biomarker panel in breast cancer: a predictor classification model

Aim: We aimed to explore the circulating expression profile of nine lncRNAs (MALAT1, HOTAIR, PVT1, H19, ROR, GAS5, ANRIL, BANCR, MIAT) in breast cancer (BC) patients relative to normal and risky individuals. Methods: Serum relative expressions of the specified long non-coding RNAs were quantified in 155 consecutive women, using quantitative reverse-transcription PCR. Random Forest (RF) and decision tree were also applied. Results: Significant MALAT1 upregulation and GAS5 downregulation could discriminate risky women from healthy controls. Overexpression of the other genes showed good diagnostic performances. Lower GAS5 levels were associated with metastasis and recurrence. RF model revealed a better performance when combining gene expression patterns with risk factors. Conclusion: The studied panel could be utilized as diagnostic/prognostic biomarkers in BC, providing promising epigenetic-based therapeutic targets.

LncRNA MALAT1 Promotes the Proliferation, Migration, and Invasion of Melanoma Cells by Downregulating miR-23a

Purpose

This study was designed to investigate the relationship between long-chain non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNA MALAT1)/miR-23a-23a and melanoma.

Patients and Methods

Fifty-two cases of corresponding non-tumor normal tissues and 109 cases (including 62 cases of primary melanoma and 47 cases of metastatic melanoma) were collected. Real-time fluorescent PCR quantified lncRNA MALAT1 and miR-23a, and counted the 3-year survival of high/low miR-23 and high/low lncRNA MALAT1 populations. We predicted the binding site according to the sequence information of lncRNA MALAT1 and miR-23a. lncRNA MALAT1 siRNA and miR-23a mimics vectors were constructed and transfected into melanoma cell lines respectively to observe their effects on cells.

Results

Compared with corresponding non-tumor normal tissues, lncRNA MALAT1 in melanoma tissue increased while miR-23a decreased. Compared with primary melanoma, metastatic melanoma was higher and miR-23a was lower. Downregulation of lncRNA MALAT1 caused upregulation of miR-23a, and lncRNA MALAT1 could bind to miR-23a. Downregulating lncRNA MALAT1 or upregulating miR-23a inhibited cell proliferation, migration and invasion and promoted apoptosis. Rescue experiments revealed that downregulation of miR-23a could offset cell changes caused by downregulation of lncRNA MALAT1.

Conclusion

lncRNA MALAT1 promotes malignant proliferation of melanoma cells through miR-23a.

Comprehensive Analysis of LincRNAs in Classical and Basal-Like Subtypes of Pancreatic Cancer

Pancreatic ductal adenocarcinomas (PDAC) belong to the deadliest malignancies in the western world. Mutations in TP53 and KRAS genes along with some other frequent polymorphisms occur almost universally and are major drivers of tumour initiation. However, these mutations cannot explain the heterogeneity in therapeutic responses and differences in overall survival observed in PDAC patients. Thus, recent classifications of PDAC tumour samples have leveraged transcriptome-wide gene expression data to account for epigenetic, transcriptional and post-transcriptional mechanisms that may contribute to this deadly disease. Intriguingly, long intervening RNAs (lincRNAs) are a special class of long non-coding RNAs (lncRNAs) that can control gene expression programs on multiple levels thereby contributing to cancer progression. However, their subtype-specific expression and function as well as molecular interactions in PDAC are not fully understood yet. In this study, we systematically investigated the expression of lincRNAs in pancreatic cancer and its molecular subtypes using publicly available data from large-scale studies. We identified 27 deregulated lincRNAs that showed a significant different expression pattern in PDAC subtypes suggesting context-dependent roles. We further analyzed these lincRNAs regarding their common expression patterns. Moreover, we inferred clues on their functions based on correlation analyses and predicted interactions with RNA-binding proteins, microRNAs, and mRNAs. In summary, we identified several PDAC-associated lincRNAs of prognostic relevance and potential context-dependent functions and molecular interactions. Hence, our study provides a valuable resource for future investigations to decipher the role of lincRNAs in pancreatic cancer.

MALAT1 and BACH1 are prognostic biomarkers for triple-negative breast cancer

Aims

The purpose of this study was to investigate the potential correlation between metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and the transcription factor BTB and CNC homology 1 (BACH1) and their clinicopathological significance in triple-negative breast cancer (TNBC).

Subjects and Methods

MALAT1 and BACH1 were detected by immunohistochemistry using TNBC tissue microarrays of 240 patients. The association between MALAT1 and BACH1 expression levels was statistically analyzed. Moreover, the prognostic roles as well as clinical and pathological significance of MALAT1 and BACH1 expression in TNBC were determined.

Statistical Analysis Used

Two-tailed Pearson correlation was used to examine the correlation of BACH1 and MALA1 expression. Comparisons of clinicopathological variables between different BACH1 and MALA1 expression groups were performed using χ² tests. Overall survival (OS) and disease-free survival (DFS) curves were plotted with the Kaplan-Meier method and the differences in OS and DFS between three groups were compared by the log-rank test. Multiple comparisons were performed using χ² tests for subsequent individual group comparisons.

Results

MALAT1 and BACH1 expression was significantly correlated with tumor-node-metastasis stage, distant metastasis, pathological stage, and survival outcomes of patients. Patients with high MALAT1 and BACH1 expression exhibited shorter overall survival and disease-free survival.

Conclusions

These findings provide further insight into the expression pattern of MALAT1 and BACH1 in TNBC and suggest them as prognostic biomarkers for TNBC.

Genome-wide transcriptome profiling of ex-vivo precision-cut slices from human pancreatic ductal adenocarcinoma

Ex-vivo tumor tissue culture systems are used as models to test specific anti-cancer drugs. Their main advantage is that they are closely comparable with the in vivo tumor in their host organism. We previously reported that precision-cut organotypic tissue slices of pancreatic ductal adenocarcinoma (PDAC) can be successfully cultured ex-vivo for at least 4 days. In order to study how culturing might affect transcription patterns, we now performed genome-wide transcriptome profiling of both baseline (0 h) and explanted tumors at daily intervals (24, 48 and 72 h) after start of culturing. The total-RNA from five samples of surgically resected human PDAC tumors at baseline and at different time points in culture was sequenced. Differential gene expression analysis of the whole transcriptome, testing 58,713 genes and over 206,000 transcripts, found that only a small number of genes showed significant changes in expression between baseline and cultured samples. The cultured tumor slices showed upregulation of a median of 12, 10 and 15 genes and downregulation of a median of 15, 12 and 25 genes at 24, 48 and 72 h in culture, respectively. One sample had morphologically increasing loss of tissue viability (range 0-18%). The vascular endothelial growth factor A (VEGFA) was significantly upregulated during the entire culture period in this case. Pathway over-representation analysis suggested that VEGFA together with the PTGS2 gene were upregulated at the same time as HIF-1-triggered cell apoptosis via NF-ĸB and the AP-1 activating factor was induced. Indeed, increased areas of apoptotic lesions were visible in this sample after 24 hours of culture. In conclusion, genome-wide transcriptome analysis supports that ex-vivo cultured tissue slices of PDAC may be a representative model of the original tumor. Transcriptome analysis was found to be a valuable complement to morphology for evaluation of ex-vivo cultures of PDAC.

MALAT1 Long Non-Coding RNA: Functional Implications

The mammalian genome is pervasively transcribed and the functional significance of many long non-coding RNA (lncRNA) transcripts are gradually being elucidated. Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is one of the most well-studied lncRNAs. MALAT1 is a highly conserved nuclear retained lncRNA that is abundantly expressed in cells and tissues and has been shown to play a role in regulating genes at both the transcriptional and post-transcriptional levels in a context-dependent manner. However, Malat1 has been shown to be dispensable for normal development and viability in mice. Interestingly, accumulating evidence suggests that MALAT1 plays an important role in numerous diseases including cancer. Here, we discuss the current state-of-knowledge in regard to MALAT1 with respect to its function, role in diseases, and the potential therapeutic opportunities for targeting MALAT1 using antisense oligonucleotides and small molecules.

The Long Non-Coding RNA MALAT1 Enhances Ovarian Cancer Cell Stemness by Inhibiting YAP Translocation from Nucleus to Cytoplasm

BACKGROUND The purpose of this work was to unearth the effects and underlying mechanism of long non-coding RNA (lncRNA) MALAT1 in ovarian cancer cell stemness. MATERIAL AND METHODS Western blot, quantitative polymerase chain reaction (qPCR) and sphere forming analysis were performed to evaluate the stem-like traits of cells and MALAT1-induced effects on ovarian cancer cell stemness. Cell viability was performed to evaluate MALAT1 role in the chemoresistance of ovarian cancer cells. RNA immunoprecipitation (RIP) and luciferase reporter analysis were constructed to investigate the underlying mechanisms. RESULTS Here, qPCR assay showed that MALAT1 level was remarkably higher in non-adherent spheres formed by adherent ovarian cancer cells, as well as cisplatin-resistant ovarian cancer cells. Additionally, MALAT1 knockdown reduced ovarian cancer cell stemness, characterized as the decrease of sphere forming ability, expression of stemness regulatory masters, and attenuation of cisplatin resistance. Moreover, MALAT1 interacted with yes-associated protein (YAP), inhibited its nuclear-cytoplasm translocation, promoted YAP protein stability and expression and thus increased its activity. Notably, rescuing expression of YAP attenuated the inhibition of MALAT1 knockdown on ovarian cancer cell stemness. CONCLUSIONS In conclusion, these results demonstrate a MALAT1/YAP axis responsible for ovarian cancer cell stemness.

LINC00963 Functions as an Oncogene in Bladder Cancer by Regulating the miR-766-3p/MTA1 Axis

Purpose

Long non-coding RNAs have been found to be involved in bladder cancer development. This article studied LINC00963 effects on bladder cancer progression to provide a novel treatment target.

Patients and Methods

Totally 56 bladder cancer patients participated in this research. Bladder cancer cells were transfected. Cell counting kit 8 assay and clone formation experiment were used for cell viability and colony formation detection. Cell migration and invasion were determined by Transwell experiment. LINC00963 distribution was explored by cytoplasmic and nuclear extract isolation and quantitative real-time polymerase chain reaction. Luciferase reporter experiment and RNA pulldown experiment were performed to detect the relationship between these two genes. The cancer genome atlas analysis was used for the detection of metastasis-associated protein 1 (MTA1) expression in bladder cancer.

Results

LINC00963 was seriously up-regulated in bladder cancer patients. High LINC00963 expression indicated high histological grade and low survival. LINC00963 was obviously up-regulated in bladder cancer cells. Knockdown of LINC00963 significantly reduced bladder cancer cells viability, colony formation, migration and invasion. Luciferase reporter experiment and RNA pulldown experiment revealed that LINC00963 promoted MTA1 expression via directly inhibiting miR-766-3p. MTA1 was up-regulated in bladder cancer patients. MTA1 up-regulation reversed the inhibitory effect of LINC00963 knockdown on bladder cancer cell viability, migration and invasion.

Conclusion

LINC00963 functions as an oncogene in bladder cancer by regulating the miR-766-3p/MTA1 axis.

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.

Nuclear hubs built on RNAs and clustered organization of the genome

RNAs play diverse roles in formation and function of subnuclear compartments, most of which are associated with active genes. NEAT1 and NEAT2/MALAT1 exemplify long non-coding RNAs (lncRNAs) known to function in nuclear bodies; however, we suggest that RNA biogenesis itself may underpin much nuclear compartmentalization. Recent studies show that active genes cluster with nuclear speckles on a genome-wide scale, significantly advancing earlier cytological evidence that speckles (aka SC-35 domains) are hubs of concentrated pre-mRNA metabolism. We propose the 'karyotype to hub' hypothesis to explain this organization: clustering of genes in the human karyotype may have evolved to facilitate the formation of efficient nuclear hubs, driven in part by the propensity of ribonucleoproteins (RNPs) to form large-scale condensates. The special capacity of highly repetitive RNAs to impact architecture is highlighted by recent findings that human satellite II RNA sequesters factors into abnormal nuclear bodies in disease, potentially co-opting a normal developmental mechanism.

PD-1/PD-L1 pathway: current researches in cancer

Cancer immunotherapy has been accompanied by promising results over the past few years. Programmed Cell Death Protein 1 (PD-1) plays a vital role in inhibiting immune responses and promoting self-tolerance through modulating the activity of T-cells, activating apoptosis of antigen-specific T cells and inhibiting apoptosis of regulatory T cells. Programmed Cell Death Ligand 1 (PD-L1) is a trans-membrane protein that is considered to be a co-inhibitory factor of the immune response, it can combine with PD-1 to reduce the proliferation of PD-1 positive cells, inhibit their cytokine secretion and induce apoptosis. PD-L1 also plays an important role in various malignancies where it can attenuate the host immune response to tumor cells. Based on these perspectives, PD-1/PD-L1 axis is responsible for cancer immune escape and makes a huge effect on cancer therapy. This review is aimed to summarize the role of PD-1 and PD-L1 in cancer, looking forward to improve the therapy of cancer.

The Roles of lncRNA in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma derives from keratinocytes and is the second most common cause of non-melanoma skin cancer. Cutaneous squamous cell carcinoma (cSCC) develops rapidly and is also the leading cause of death in non-melanoma cancers. Lymph node metastasis occurs in 5% of cSCC patients, and some patients may even metastasize to the viscera. Patients with regional lymphatic metastasis or distant metastases have a <20% 10-year survival rate, indicating the substantial challenge in treating advanced and metastatic cSCC. Some lncRNAs have been found to be abnormally overexpressed in many tumor tissues, so that they can be considered as potential new biomarkers or targets that can be used in the diagnosis and treatment of cSCC in the future. In this review, we summarize the role of lncRNA in cutaneous squamous cell carcinoma to make a better understanding of mutations in cSCC and lay the foundation for effective target therapy of cSCC.

LncRNA MALAT1 contributes to non-small cell lung cancer progression via modulating miR-200a-3p/programmed death-ligand 1 axis

This study was to investigate the expression correlation between long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNA MALAT1), miR-200a-3p and programmed death-ligand 1 (PD-L1) in non-small cell lung cancer (NSCLC), and their roles in NSCLC. Real-time polymerase chain reaction (PCR) was performed to detect the expressions of MALAT1, miR-200a-3p and PD-L1 in NSCLC tissues and cells for the correlation analysis. The starBase and Targetscan databases were used to predict the binding sites between MALAT1 and miR-200a-3p, and miR-200a-3p and PD-L1, respectively. The targeting relationship between MALAT1 and miR-200a-3p, and miR-200a-3p and PD-L1 were further verified by real-time PCR and dual luciferase reporter gene assay. Cell proliferation was monitored by CCK8 and colony formation assays. The apoptosis was detected using flow cytometry. Wound healing assay and transwell assay were conducted to determine cell migration and invasion. In this study, we demonstrated that in NSCLC tissues, the expression level of MALAT1 was negatively correlated with that of miR-200a-3p, while positively correlated with PD-L1. Besides, MALAT1 promoted proliferation, mobility, migration, and invasion of NSCLC cells via sponging miR-200a-3p. PD-L1 was validated as a target of miR-200a-3p, and indirectly modulated by MALAT1. In conclusion, LncRNA MALAT1 facilitates the progression of NSCLC by modulating miR-200a-3p/PDL1 axis.

Evaluation of MALAT1 promoter DNA methylation patterns in early colorectal lesions and tumors

AIM

This study set out to determine the effect of methylation on MALAT1 gene in primary colorectal lesions and tumors to gain further knowledge about the diagnostic and prognostic value of MALAT.

BACKGROUND

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is one of the long non-coding RNAs that plays an important role in invasion, cell proliferation, and metastasis of various cancers. However, there is insufficient information on the association between MALAT1 and the methylation process as well as its role in the development of colorectal cancer.

METHODS

Methylation pattern of MALAT1 promoter was determined by Methylation-Specific Polymerase Chain Reaction (MSP) in 86 colorectal primary lesions, tumors, and normal specimens. MALAT1 methylation pattern was compared in tumor and polyp tissue. In order to obtain more accurate results, we investigated the association between MALAT1 promoter methylation pattern and clinicopathologic factors in patients.

RESULTS

The results indicated that the MALAT1 promoter methylation pattern in the tumor tissue, primary lesion tissue, and normal was not significantly different (p=0.430). Comparison of the MALAT1 promoter methylation pattern between polyp types and tumor tissue groups was not significant either (p=0.437). Surprisingly, the methylation frequency of MALAT1 methylation was significantly higher in colon lesions than in their rectum lesion (p = 0.035). In addition, no significant hypermethylation of MALAT1 was observed between the other patients' clinicopathological data in both polyp 46/66 and tumor tissues 20/66.

CONCLUSION

This study dealt with determining the effect of methylation on MALAT1 gene in primary colorectal lesions and tumors to gain further knowledge about the diagnostic and prognostic value of MALAT.