Levels Of MALAT1 Research Articles

Abstract 2343: Role of calreticulin in the regulation of MALAT-1 expression in mouse adenocarcinoma cells

Abstract Calreticulin (CRT) is a ubiquitously expressed protein, with both calcium binding and chaperone activity. CRT is involved in quality control process during the folding and maturation of proteins in ER. Recently, we showed that overexpression of CRT resulted in the development of metastatic lung adenocarcinoma. In order to examine genes involved in the development of lung cancer we carried out microarray analysis on RNA isolated from mouse lung tumors versus control. In this screen we observed a significant increase in long noncoding RNA (LncRNA) MALAT-1 in the lungs of CRT overexpressing mouse models. MALAT-1 is a LncRNA that has been documented to be upregulated in the human lung adenocarcinoma and associated with metastasis. Our study was to investigate the mechanism of regulation of MALAT-1 expression and role of CRT in this process. We hypothesized that CRT as a regulator of intracellular calcium regulated MALAT-1 expression thus inducing the development of metastatic lung adenocarcinoma in our mice model. Our data showed a significant correlation between intracellular calcium levels and MATAT-1 RNA expression and stability. Treatment of adenocarcinoma cells with BAPTA-AM resulted in a significant reduction in MALAT-1 level. Treating the cells with thapsigargin induced a 2 fold increase in MALAT-1 expression. We also demonstrated that knock down of MALA-1 expression using specific siRNA reduces the proliferation of adenocarcinoma cell. Our data demonstrate for the first time involvement of calcium binding protein CRT and intracellular level of calcium on expression and stability of MALAT-1 involved in development of lung adenocarcinoma. Funded by NPRP4-043-3-016 Citation Format: Hamid Massaeli, Divya Viswanathan, Dhanya Pillai, Nasrin Mesaeli. Role of calreticulin in the regulation of MALAT-1 expression in mouse adenocarcinoma cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2343. doi:10.1158/1538-7445.AM2014-2343

Abstract 3553: The expression of metastasis-associated long non-coding RNA, HOTAIR, is involved in cancer development and peritoneal metastasis in gastric cancer

Abstract Purpose. The prognosis of advanced gastric cancer patients with peritoneal dissemination remains poor, and a better understanding of this mechanism is critical for development of new treatments that can improve patient survival. Long non-coding RNAs (lncRNAs) are most commonly defined as transcripts of greater than 200 nucleotides in length. Recent evidence suggests that lncRNAs are differentially expressed in cancer cells and have a major role in the development of cancer progression, including metastasis. This study aimed to investigate the clinical and biological significance of metastasis-associated lncRNA in gastric cancer. Experimental Design. We analyzed MALAT1 and HOTAIR expression levels by real-time reverse transcription PCR in 300 gastric tissues (150 gastric cancer tissues and 150 adjacent normal mucosa), and in seven gastric cancer cell lines. Knockdown of the HOTAIR by siRNA transfection was performed to evaluate HOTAIR function in gastric cancer cell lines and animal models. Results. Expression of MALAT1 and HOTAIR were significantly higher in cancerous tissues than in adjacent normal mucosa, and high expression of both lncRNAs significantly correlated with peritoneal metastasis in gastric cancer. In addition, elevated HOTAIR expression was an independent prognostic factor, and was an independent risk factor for peritoneal dissemination. SiRNA knockdown of HOTAIR in MKN45 and KATO-III cell lines resulted in reduced cell proliferation, colony formation, migration and invasion, but simultaneous increase in anoikis rates, compared to the controls. In an in vivo assay, HOTAIR siRNA-transfected MKN45 cells injected into nude mice inhibited the growth of xenograft tumors and peritoneal metastasis compared with scrambled siRNA-transfected cells. Conclusions. Our data highlight that HOTAIR expression may serve as a potentially important disease biomarker for the identification of high-risk gastric cancer patients. Moreover, our findings provide extensive mechanistic evidence for the functional role of HOTAIR over-expression and the ensuing malignant phenotype in gastric cancer cells in both cultured cells and two different animal models (xenograft and peritoneal metastasis). We propose that HOTAIR lncRNA could be used as a clinically useful diagnostic and prognostic biomarker for gastric cancer patients, and might be a novel therapeutic target for developing gastric cancer treatments. Citation Format: Yoshinaga Okugawa, Yuji Toiyama, Keun Hur, Shusuke Toden, Susumu Saigusa, Koji Tanaka, Yasuhiro Inoue, Yasuhiko Mohri, Masato Kusunoki, C. R. Boland, Ajay Goel. The expression of metastasis-associated long non-coding RNA, HOTAIR, is involved in cancer development and peritoneal metastasis in gastric cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3553. doi:10.1158/1538-7445.AM2014-3553

A novel wnt regulatory axis in endometrioid endometrial cancer.

The Protocadherin 10 (PCDH10) is inactivated often by promoter hypermethylation in various human tumors, but its possible functional role as a tumor suppressor gene is not established. In this study, we identify PCDH10 as a novel Wnt pathway regulatory element in endometrioid endometrial carcinoma (EEC). PCDH10 was downregulated in EEC tumor cells by aberrant methylation of its promoter. Restoring PCDH10 levels suppressed cell growth and triggered apoptosis in EEC cells and tumor xenografts. Gene expression profiling revealed as part of the transcriptomic changes induced by PCDH10 a reduction in levels of MALAT1, a long noncoding RNA, that mediated tumor suppression functions of PCDH10 in EEC cells. We found that MALAT1 transcription was regulated by Wnt/β-catenin signaling via TCF promoter binding and PCDH10 decreased MALAT1 by modulating this pathway. Clinically, MALAT1 expression was associated with multiple parameters in patients with EEC. Taken together, our findings establish a novel PCDH10-Wnt/β-catenin-MALAT1 regulatory axis that contributes to EEC development. Cancer Res; 74(18); 5103-17. ©2014 AACR.

OP0106 The Impact of Pro-Inflammatory Cytokines on the Expression and Function of Long Noncoding RNA (LNCRNA) in Rheumatoid Arthritis Synovial Fibroblasts

BackgroundLong noncoding RNA (lncRNA) have emerged as key regulators of gene expression. Recently, new susceptibility loci were identified for severity of rheumatoid arthritis (RA), mapping to different lncRNA genes (Knevel...

Expression and Prognostic Significance of lncRNA MALAT1 in Pancreatic Cancer Tissues

Long non-coding RNAs (lncRNAs) have been recently observed in various human cancers. However, the role of lncRNAs in pancreatic duct adenocarcinoma (PDAC) remains unclarified. The aim of this study was to detect the expression of lncRNA MALAT1 in PDAC formalin-fixed, paraffin embedded (FFPE) tissues and to investigate the clinical significance of the MALAT1 level. The expression of MALAT1 was examined in 45 PDAC and 25 adjacent non-cancerous FFPE tissues, as well as in five PDAC cell lines and a normal pancreatic epithelium cell line HPDE6c-7, using qRT-PCR. The relationship between MALAT1 level and clinicopathological parameters of PDAC was analyzed with the Kaplan-Meier method and Cox proportional hazards model. The relative level of MALAT1 was significantly higher in PDAC compared to the adjacent normal pancreatic tissues (p=0.009). When comparing the MALAT1 level in the cultured cell lines, remarkably higher expression of MALAT1 was found in aspc-1 PDAC cells compared with the immortal pancreatic duct epithelial cell line HPDE6c-7 (q=7.573, p<0.05). Furthermore, MALAT1 expression level showed significant correlation with tumor size (r=0.35, p=0.018), tumor stage (r=0.439, p=0.003) and depth of invasion (r=0.334, p=0.025). Kaplan-Meier analysis revealed that patients with higher MALAT1 expression had a poorer disease free survival (p=0.043). Additionally, multivariate analysis indicated that overexpression of MALAT1, as well as the tumor location and nerve invasion, was an independent predictor of disease-specific survival of PDAC. MALAT1 might be considered as a potential prognostic indicator and may be a target for diagnosis and gene therapy for PDAC.

TGF-β–Induced Upregulation of malat1 Promotes Bladder Cancer Metastasis by Associating with suz12

TGF-β promotes tumor invasion and metastasis by inducing an epithelial-mesenchymal transition (EMT). However, the underlying mechanisms causing this are not entirely clear. Long noncoding RNAs (lncRNA) have been shown to play important regulatory roles in cancer progression. The lncRNA malat1 (metastasis associated lung adenocarcinoma transcript 1) is a critical regulator of the metastasis phenotype of lung cancer cells. We, therefore, investigated whether TGF-β regulates malat1 expression to promote tumor metastasis of bladder cancer. The expression levels of malat1 and EMT markers were assayed in specimens of bladder cancer. The role of malat1 in regulating bladder cancer metastasis was evaluated in cell and animal models. TGF-β induces malat1 expression and EMT in bladder cancer cells. malat1 overexpression is significantly correlated with poor survival in patients with bladder cancer. malat1 and E-cadherin expression is negatively correlated in vitro and in vivo. malat1 knockdown inhibits TGF-β-induced EMT. malat1 is associated with suppressor of zeste 12 (suz12), and this association results in decrease of E-cadherin expression and increase of N-cadherin and fibronectin expression. Furthermore, targeted inhibition of malat1 or suz12 suppresses the migratory and invasive properties induced by TGF-β. Finally, we demonstrated that malat1 or suz12 knockdown inhibits tumor metastasis in animal models. These data suggest that malat1 is an important mediator of TGF-β-induced EMT, and suggest that malat1 inhibition may represent a promising therapeutic option for suppressing bladder cancer progression.

LncRNAs expression signatures of hepatocellular carcinoma revealed by microarray.

To analyze the expression profiles of long non-coding RNAs (lncRNAs) in hepatocellular carcinoma. Hepatocellular carcinoma (HCC) tissues and matched adjacent non-tumor (NT) liver tissues were collected from 29 patients with HCC, immediately after liver resection, between March 2011 and July 2013. The diagnosis of HCC was made based on histological examination. Differentially expressed lncRNAs between HCC and NT tissues were revealed through microarray-based lncRNAs expression profiling. Further, quantification of selected lncRNAs was performed using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Six hundred and fifty-nine lncRNAs were differentially expressed between HCC and NT tissues, of which five [TCONS_00018278, AK093543, D16366, ENST00000501583, NR_002819 (MALAT1)] were selected for validation. Four of them were significantly downregulated in HCC tissues compared with NT tissues (P = 0.012, 0.045, 0.000 and 0.000, respectively), and the expression level of MALAT1 showed no significant difference (P = 0.114). This study identified a set of lncRNAs differentially expressed in HCC tissues and provided useful information for exploring potential therapeutic targets and diagnostic biomarkers of this cancer.

Long Noncoding RNA MALAT1 Controls Cell Cycle Progression by Regulating the Expression of Oncogenic Transcription Factor B-MYB

The long noncoding MALAT1 RNA is upregulated in cancer tissues and its elevated expression is associated with hyper-proliferation, but the underlying mechanism is poorly understood. We demonstrate that MALAT1 levels are regulated during normal cell cycle progression. Genome-wide transcriptome analyses in normal human diploid fibroblasts reveal that MALAT1 modulates the expression of cell cycle genes and is required for G1/S and mitotic progression. Depletion of MALAT1 leads to activation of p53 and its target genes. The cell cycle defects observed in MALAT1-depleted cells are sensitive to p53 levels, indicating that p53 is a major downstream mediator of MALAT1 activity. Furthermore, MALAT1-depleted cells display reduced expression of B-MYB (Mybl2), an oncogenic transcription factor involved in G2/M progression, due to altered binding of splicing factors on B-MYB pre-mRNA and aberrant alternative splicing. In human cells, MALAT1 promotes cellular proliferation by modulating the expression and/or pre-mRNA processing of cell cycle–regulated transcription factors. These findings provide mechanistic insights on the role of MALAT1 in regulating cellular proliferation.

MALAT-1, a non protein-coding RNA is upregulated in the cerebellum, hippocampus and brain stem of human alcoholics

Chronic alcohol intake induces neurochemical adaptative changes in the brain characterised by altered gene expression. A role for non-coding RNAs in alcoholism is beginning to emerge. PCR-differential display using total RNA extracted from brain material of human alcoholics and control cases identified a cDNA fragment corresponding to a section of a known non protein-coding RNA (ncRNA), MALAT-1, (also known as NEAT2). Comparison of mRNA levels of MALAT-1 was performed by northern and dot blot experiments using different regions of brain from human alcoholics and rats chronically treated with ethanol vapours and following withdrawal. A massive increase of MALAT-1 transcripts was detected in cerebellum of human alcoholics and increases were also noted in hippocampus and brain stem, while no significant increase of MALAT-1 expression was noted in frontal or motor cortices. In the rat no significant difference of MALAT-1 ortholog mRNA could be detected in cerebellum. In addition, similarly to humans, no significant increase of MALAT-1 expression was detected in cortex of alcohol-treated rats, however, after 24 h alcohol withdrawal, a significant upregulation of MALAT-1 expression was observed in rat cortex. MALAT-1 is upregulated in specific regions of the human alcoholic brain and following alcohol withdrawal in the rat. As MALAT-1 regulates RNA processing, this suggests that alcohol-induced upregulation of MALAT-1 represents an important novel mechanism for alcohol actions in the CNS.

Upregulated MALAT-1 contributes to bladder cancer cell migration by inducing epithelial-to-mesenchymal transition

Recent studies reveal that long non-coding RNAs (lncRNAs) have been shown to have important regulatory roles in cancer biology, and lncRNA MALAT-1 expression is upregulated in some tumors. However, the contributions of MALAT-1 to bladder cancer metastasis remain largely unknown. In the present study we evaluated MALAT-1 expression in bladder cancer tissues by real-time PCR, and defined its biological functions. We verified that MALAT-1 levels were upregulated in bladder cancer tissues compared with adjacent normal tissues, and MALAT-1 expression was remarkably increased in primary tumors that subsequently metastasized, when compared to those primary tumors that did not metastasize. SiRNA-mediated MALAT-1 silencing impaired in vitro bladder cancer cell migration. Downregulation of MALAT-1 resulted in a decrease of the epithelial-mesenchymal transition (EMT)-associated ZEB1, ZEB2 and Slug levels, and an increase of E-cadherin levels. We further demonstrated that MALAT-1 promoted EMT by activating Wnt signaling in vitro. These data suggest an important role for MALAT-1 in regulating metastasis of bladder cancer and the potential application of MALAT-1 in bladder cancer therapy.

A survey of the sensitivity of fresh clinical isolates to cefuroxime and other antibiotics.

The sensitivities to cefuroxime and cephradine of potentially pathogenic bacteria isolated in two British general hospitals comprising 900 beds have been assessed. In a three-month period 2537 strains were studied; 30 microgram cefuroxime discs were used with 2511 strains, and cephradine discs of the same strength were used with 2525 strains. The organisms were also examined routinely for sensitivity to other antibiotics. Overall, 91.7% of the isolates were sensitive to cefuroxime and 85.8% were inhibited by cephradine, the differences in percentage strain susceptibility to cefuroxime and cephradine being mainly a result of the greater activity of cefuroxime against the Gram-negative bacteria. The wide antibacterial effectiveness of cefuroxime should make it a useful antibiotic for the treatment of serious infections including those conditions in which the causative organism has not been identified.