Long non-coding RNA HOTAIR modulates c-KIT expression through sponging miR-193a in acute myeloid leukemia

HOTAIR as a Prognostic Predictor for Diverse Human Cancers: A Meta- and Bioinformatics Analysis

Several studies suggest that upregulated expression of the long non-coding RNA HOX transcript antisense RNA (HOTAIR) is a negative predictive biomarker for numerous cancers. Herein, we performed a meta-analysis to further investigate the prognostic value of HOTAIR expression in diverse human cancers. To this end, a systematic literature review was conducted in order to select scientific studies relevant to the association between HOTAIR expression and clinical outcomes, including overall survival (OS), recurrence-free survival (RFS)/disease-free survival (DFS), and progression-free survival (PFS)/metastasis-free survival (MFS) of cancer patients. Collectively, 53 eligible studies including a total of 4873 patients were enrolled in the current meta-analysis. Pooled hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) were calculated to assess the relationship between HOTAIR and cancer patients’ survival. Elevated HOTAIR expression was found to be significantly associated with OS, RFS/DFS and PFS/MFS in diverse types of cancers. These findings were also corroborated by the results of bioinformatics analysis on overall survival. Therefore, based on our findings, HOTAIR could serve as a potential biomarker for the prediction of cancer patient survival in many different types of human cancers.

Overexpression of ZEB2-AS1 lncRNA is associated with poor clinical outcomes in acute myeloid leukemia

Acute myeloid leukemia (AML) is a fatal hematopoietic malignancy with poor clinical outcomes. To determine whether the expression of the long non-coding (lnc)RNA zinc finger E-box binding homeobox 2 (ZEB2) antisense RNA 1 (ZEB2-AS1) is associated with clinical outcomes, its expression was analyzed in a retrospective cohort of 62 AML and 10 non-malignant cases. The results revealed that the expression of ZEB2-AS1 lncRNA was notably high and closely associated with adverse clinical outcomes in AML cases compared with the non-malignant cases, based on either modified Medical Research Council or European Leukemia Net risk stratification systems. Univariate analyses indicated that patients with a higher expression of ZEB2-AS1 lncRNA had significantly shorter overall survival (OS) (P=0.036) and disease-free survival (DFS) rates (P=0.039) compared with patients with a lower expression of ZEB2-AS1 lncRNA. In addition, patients with a higher expression of ZEB2-AS1 lncRNA had a significant lower complete remission rate in response to induction by chemotherapy compared with patients with a lower expression of ZEB2-AS1 lncRNA (P=0.031). In cases with low levels of ZEB2-AS1 lncRNA, patients treated with allogenic hematopoietic stem cell transplantation had significantly longer OS and DFS rates compared with that of chemotherapy-treated patients (P=0.037 and P=0.049 respectively). Furthermore, the knockdown of ZEB2-AS1 lncRNA effectively inhibited AML cell invasion and migration, which was closely associated with the downregulation of ZEB2 and upregulation of E-cadherin expression. Collectively, although its independent prognostic value for survival was not rigorously determined, ZEB2-AS1 lncRNA may function as a candidate marker to improve conventional risk stratification systems and the evaluation of therapeutic responses for AML.

Interaction between 12p chromosomal abnormalities and Lnc-HOTAIR mediated pathway in acute myeloid leukemia

OBJECTIVES

To investigate the correlation of homeobox (HOX) transcript antisense RNA expression with clinicopathological features and the clinical prognosis of the patients with chromosome 12p abnormalities associated acute myeloid leukemia (AML). We also investigate the association of 12p chromosomal on the expression of HOTAIR, miRNA-193a, and c-kit gene as targeting genes for HOTAIR in AML.

METHODS

AML patients with 12p chromosomal abnormalities were recruited and compared to AML with other chromosomal abnormalities rather than 12p. The long noncoding RNA (lncRNA) "HOTAIR," miR-193a, and c-Kit genes expression were measured in bone marrow samples using Syber green based real-time polymerase chain reaction.

RESULTS

We found a significant difference for the expression levels of HOTAIR, c-kit, and miR-193a between 12p abnormalities associated AML and those without. The survival analysis revealed that patient's with low expression levels of HOTAIR and c-kit had significantly better survival and leukemia free survival. In contrast, miR-193a was associated with better overall survival but not leukemia free survival.

CONCLUSION

12p abnormalities associated AML were associated with worse prognosis. Our results proved that HOTAIR, miR-193a, and c-kit genes are independent prognostic predictors in 12p chromosomal associated AML; therefore it may represent a novel therapeutic application in AML in the future.

Silencing long non-coding RNA HOTAIR exerts anti-oncogenic effect on human acute myeloid leukemia via demethylation of HOXA5 by inhibiting Dnmt3b

Background

As an aggressive hematological malignancy, acute myeloid leukemia (AML) remains a dismal disease with poor prognosis. Long non-coding RNAs (lncRNAs) have been widely reported to be involved in tumorigenesis of AML. Here, we define an important role of lncRNA HOTAIR in AML in relation to HOXA5 methylation.

Methods

Firstly, the expression of HOTAIR was examined in AML samples and cells collected. Next, gain- or loss-of function experiments were conducted in AML cells to explore the effect of HOTAIR on AML. Then, relationship among HOXA5 promoter methylation, HOTAIR and Dnmt3b was measured. Expression of HOXA5 and cell proliferation/apoptosis-related genes was also detected. A last, in vivo assay was performed to assess the tumor formation in nude mice in order to explore the roles of HOTAIR and HOXA5 in cell apoptosis and proliferation.

Results

LncRNA HOTAIR was found to be upregulated in AML cells and tissues. With silencing of HOTAIR and overexpression of HOXA5, AML cell proliferation was decreased while the apoptosis was induced. Furthermore, HOTAIR was observed to recruit Dnmt3b and to increase HOXA5 promoter methylation. Moreover, silencing HOTAIR and upregulating HOXA5 were found to induce apoptosis and reduce proliferation of AML cells in vivo.

Conclusion

Our findings highlight the anti-tumor ability of HOTAIR silencing in AML, suggesting that silencing HOTAIR was able to inhibit AML progression through HOXA5 promoter demethylation by decreasing Dnmt3b.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0808-z) contains supplementary material, which is available to authorized users.

miR-193a targets MLL1 mRNA and drastically decreases MLL1 protein production: Ectopic expression of the miRNA aberrantly lowers H3K4me3 content of the chromatin and hampers cell proliferation and viability

Mixed-lineage leukaemia 1 (MLL1) enzyme plays major role in regulating genes associated with vertebrate development. Cell physiology and homeostasis is regulated by microRNAs in diverse microenvironment. In this investigation we have identified conserved miR-193a target sites within the 3'-UTR of MLL1 gene transcript. Utilizing wild type and mutated 3'-UTR constructs and luciferase reporter assays we have clearly demonstrated that miR-193a directly targets the 3'-UTR region of the MLL1 mRNA. Ectopic expression of miR-193a modulated global H3K4 mono-, di- and tri-methylation levels and affects the expression of CAV1, a gene which is specifically modulated by H3K4me3. To determine the implications of this in vitro finding in aberrant physiological conditions we analyzed prostate cancer tissue samples. In this context miR-193a RNA was undetectable and MLL1 was highly expressed with concomitantly high levels of H3K4me, H3K4me2, and H3K4me3 enrichment in the promoters of MLL1 responsive genes. Finally, we showed that prolonged ectopic expression of miR-193a inhibits growth and cell migration, and induces apoptosis. Thus, while our study unveils amplitude of the epigenome, including miRnome it establishes that; (i) miR-193a directly target MLL1 mRNA, (ii) miR-193a impair MLL1 protein production, (iii) miR-193a reduces the overall methylation marks of the genome.

Long noncoding RNAs biomarker-based cancer assessment

Cancer diagnosis have mainly relied on the incorporation of molecular biomarkers as part of routine diagnostic tool. The molecular alteration ranges from those involving DNA, RNA, noncoding RNAs (microRNAs and long noncoding RNAs [lncRNAs]) and proteins. lncRNAs are recently discovered noncoding endogenous RNAs that critically regulates the development, invasion, and metastasis of cancer cells. They are dysregulated in different types of malignancies and have the potential to serve as diagnostic markers for cancer. The expression of noncoding RNAs is altered following many diseases, and besides, some of them can be secreted from the cells into the circulation following the apoptotic and necrotic cell death. These secreted noncoding RNAs are known as cell free RNA. These RNAs can be secreted from the cell through the apoptotic body, extracellular vesicles including microvesicle and exosome, and bind to proteins. Since, lncRNAs display high organ and cell specificity, can be found in the blood, urine, tumor tissue, or other tissues or bodily fluids of some patients with cancer, this review summarizes the most significant and up-to-date findings of research on lncRNAs involvement in different cancers, focusing on the potential of cancer-related lncRNAs as biomarkers for diagnosis, prognosis, and therapy.

miR-7977 inhibits the Hippo-YAP signaling pathway in bone marrow mesenchymal stromal cells

We and others have demonstrated that various abnormalities of the bone marrow (BM) mesenchymal stromal cells (MSCs) such as aberrant cytokine expression, abnormal hedgehog signaling, and impaired miRNA biogenesis are observed in patients with acute myeloid leukemia (AML). However, underlying mechanisms to induce the dysfunction of BM MSCs have not yet been clarified. We previously showed that AML cells release abundant exosomal miR-7977, which, in turn, enters BM mesenchymal stromal cells (MSCs). However, the precise function of miR-7977 is not known. In this study, we performed transduction of a miR-7977 mimic into MSCs, compared transcriptomes between control-transduced (n = 3) and miR-7977-transduced MSCs (n = 3), and conducted pathway analysis. The array data revealed that the expression of 0.05% of genes was reduced 2-fold and the expression of 0.01% of genes was increased 2-fold. Interestingly, approximately half of these genes possessed a miR-7977 target site, while the other genes did not, suggesting that miR-7977 regulates the gene expression level directly and indirectly. Gene set enrichment analysis showed that the gene sets of Yes-associated protein 1 (YAP1) _up were significantly enriched (p<0.001, q<0.25), suggesting that miR-7977 modulates the Hippo-YAP signaling pathway. Visualization of pathway and network showed that miR-7977 significantly reduced the expression of Hippo core kinase, STK4. miR-7977 inactivated the Hippo-YAP signaling pathway as proven by GFP-tagged YAP nuclear trans localization and TEAD reporter assay. The miR-7977-transduced MSC cell line, HTS-5, showed elevated saturation density and enhanced entry into the cell cycle. These results suggest that miR-7977 is a critical factor that regulates the Hippo-YAP signaling pathway in BM-MSCs and may be involved in the upregulation of leukemia-supporting stroma growth.

Long Non-Coding RNA and Acute Leukemia

Acute leukemia (AL) is the main type of cancer in children worldwide. Mortality by this disease is high in developing countries and its etiology remains unanswered. Evidences showing the role of the long non-coding RNAs (lncRNAs) in the pathophysiology of hematological malignancies have increased drastically in the last decade. In addition to the contribution of these lncRNAs in leukemogenesis, recent studies have suggested that lncRNAs could be used as biomarkers in the diagnosis, prognosis, and therapeutic response in leukemia patients. The focus of this review is to describe the functional classification, biogenesis, and the role of lncRNAs in leukemogenesis, to summarize the evidence about the lncRNAs which are playing a role in AL, and how these genes could be useful as potential therapeutic targets.

Knockdown of ZFAS1 suppresses the progression of acute myeloid leukemia by regulating microRNA-150/Sp1 and microRNA-150/Myb pathways

Leukemia is the most frequent malignancy in children with acute myeloid leukemia (AML) as the second commonest type. Long non-coding RNA zinc finger antisense 1 (ZFAS1) has been widely reported as an oncogenic factor in multiple malignancies including AML. However, the roles and molecular mechanisms of ZFAS1 in the tumorigenesis of AML are poor defined till now. In the present study, RT-qPCR assay showed that ZFAS1 was highly expressed in bone marrow of acute leukemia patients and AML cell lines. Loss-of-function analyses revealed that ZFAS1 knockdown inhibited proliferation and promoted apoptosis in AML cells and curbed AML xenograft growth in vivo. Bioinformatics analysis and luciferase reporter assay unveiled that microRNA-150 (miR-150) could interact with ZFAS1, Myb 3' UTR and Sp1 3' UTR. Moreover, ZFAS1 acted as a molecular sponge of miR-150, giving rise to the downregulation of miR-150 level and upregulation of Myb and Sp1 levels. Moreover, miR-150 overexpression resulted in the reduction of AML cell proliferative ability and the increase of cell apoptotic rate. Additionally, the inhibition of miR-150 abrogated ZFAS1 loss-mediated anti-leukemia effects. In summary, our data demonstrated that ZFAS1 knockdown hampered AML progression by regulating miR-150/Myb and miR-150/Sp1 pathways, providing some potential biomarkers or targets for the diagnosis and treatment of leukemia.

Lnc-SOX6-1 upregulation correlates with poor risk stratification and worse treatment outcomes, and promotes cell proliferation while inhibits apoptosis in pediatric acute myeloid leukemia

INTRODUCTION

To investigate the correlation of long noncoding RNA-SOX6-1 (lnc-SOX6-1) with clinicopathological features and treatment outcomes in pediatric acute myeloid leukemia (AML) patients, and further explore its function in AML cell proliferation and apoptosis.

METHODS

A total of 146 de novo pediatric AML patients and 73 nonhematologic malignancy patients/donors were recruited. Bone marrow samples were obtained, followed by measurement of lnc-SOX6-1 expression by qPCR. Besides, lnc-SOX6-1 expression in various AML cells and control cells was detected. Blank overexpression (NC (+)), lnc-SOX6-1 overexpression (Lnc RNA (+)), blank shRNA (NC (-)), and lnc-SOX6-1 shRNA plasmids (Lnc RNA (-)) were transferred into KG-1 cells and THP-1 cells. Cell proliferation rate and cell apoptosis rate were detected by CCK-8 assay and AV/PI assay, respectively.

RESULTS

Lnc-SOX6-1 expression was upregulated in pediatric AML patients compared to controls, and its high expression correlated with the presence of monosomal karyotype, severer risk stratification, lower possibility of complete response achievement, shorter event-free survival, and poor overall survival. Furthermore, lnc-SOX6-1 expression was elevated in various AML cells compared to normal cells. In KG-1 cells and THP-1 cells, cell proliferation rate was elevated in Lnc RNA (+) group but reduced in Lnc RNA (-) group at 48 and 72 hours, and cell apoptosis rate was decreased in Lnc RNA (+) group but increased in Lnc RNA (-) group at 72 hours compared to the corresponding control groups.

CONCLUSION

Lnc-SOX6-1 is highly expressed and correlates with worse risk stratification and poor treatment outcomes, and promotes cell proliferation while represses apoptosis in pediatric AML.

Long-noncoding RNA HOTAIR inhibits immunologic rejection of mouse leukemia cells through activating the Wnt/β-catenin signaling pathway in a mouse model of leukemia

Long-noncoding RNAs (lncRNAs) is involved in the development of diverse diseases, including leukemia, while the role lncRNA HOX transcript antisense RNA (HOTAIR) played in leukemia remains unclear and in need of further investigation. Therefore, this study was conducted to explore the effects of lncRNA HOTAIR on the immunologic rejection of leukemia cells through the Wnt/β-catenin in mice. Mice were administrated with HOTAIR mimics as well as small interfering RNA HOTAIR to explore the regulatory role of HOTAIR. The numbers of white blood cell (WBC) and platelet (PLT) and the content of hemoglobin in peripheral blood (PB) were determined. The cytokine level in PB was measured. T-lymphocyte proliferation activity, Ig production by B cells, natural killer (NK) cell activity, and the proportion of cluster of differentiation 4 (CD4)/CD8 T cell subsets were detected. Expression of HOTAIR, β-catenin, cyclinD1, GSK-3β, and c-Myc in bone marrow was determined. It was revealed that the WBC number increased, while the PLT number along with the hemoglobin content in PB decreased with the upregulated HOTAIR. Additionally, elevated HOTAIR led to decreased levels of transforming growth factor-β, interferon-γ, interleukin-10, and tumor necrosis factor-α in PB, proliferation activity in T-lymphocyte, and inhibited Ig production, NK cell activity, and the ratio of CD4/CD8 T cell subsets in B-lymphocyte. Furthermore, Wnt/β-catenin was activated by overexpressing HOTAIR. Enhanced survival and proliferation were shown with increased expression of cyclinD1, GSK-3β, and c-Myc in the bone marrow of mice induced by overexpressing HOTAIR. These results indicate that restored HOTAIR reduces the immunologic rejection of leukemia cells in mice by activating Wnt/β-catenin pathway.

Long Noncoding RNAs: New Players in the Osteogenic Differentiation of Bone Marrow- and Adipose-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are an important population of multipotent stem cells that differentiate into multiple lineages and display great potential in bone regeneration and repair. Although the role of protein-coding genes in the osteogenic differentiation of MSCs has been extensively studied, the functions of noncoding RNAs in the osteogenic differentiation of MSCs are unclear. The recent application of next-generation sequencing to MSC transcriptomes has revealed that long noncoding RNAs (lncRNAs) are associated with the osteogenic differentiation of MSCs. LncRNAs are a class of non-coding transcripts of more than 200 nucleotides in length. Noncoding RNAs are thought to play a key role in osteoblast differentiation through various regulatory mechanisms including chromatin modification, transcription factor binding, competent endogenous mechanism, and other post-transcriptional mechanisms. Here, we review the roles of lncRNAs in the osteogenic differentiation of bone marrow- and adipose-derived stem cells and provide a theoretical foundation for future research.

Long noncoding RNA NEAT1 modulates cell proliferation and apoptosis by regulating miR-23a-3p/SMC1A in acute myeloid leukemia

The aim of this study was to determine the function of the NEAT1/miR-23a-3p/SMC1A axis in cell proliferation and apoptosis in acute myeloid leukemia (AML). Microarray analysis was used to screen differentially expressed lncRNAs/miRNAs/mRNAs in primary AML cells. The expression of nuclear paraspeckle assembly transcript 1 (NEAT1), miR-23a-3p, and structural maintenance of chromosome 1 alpha (SMC1A) in primary AML cells and THP-1 cells were measured by quantitative real-time polymerase chain reaction (qRT-PCR). A Cell Counting Kit-8 (CCK-8) assay was used to analyze proliferation. Cell cycle progression and apoptosis were examined by flow cytometry. RNA immunoprecipitation (RIP) and dual-luciferase assays were performed to determine the correlation between miR-23a-3p and NEAT1 or SMC1A. The qRT-PCR illustrated that NEAT1 and SMC1A expression was decreased but that miR-23a-3p expression was increased in primary AML cells and THP-1 cells compared with that in normal cells. The RIP assay and dual-luciferase assay revealed the targeting relationship between miR-23a-3p and NEAT1 or SMC1A. The CCK-8 assay showed that the overexpression of NEAT1 and SMC1A or repression of miR-23a-3p inhibited cell proliferation. Flow cytometry showed that the upregulation of NEAT1 and SMC1A or repression of miR-23a-3p promoted apoptosis and affected the cell cycle. NEAT1 repressed the expression of miR-23a-3p, and therefore promoted SMC1A, which in turn suppressed myeloid leukemia cell proliferation and enhanced apoptosis.

Long noncoding RNA HOTAIR promotes the self-renewal of leukemia stem cells through epigenetic silencing of p15

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic disorder initiated from a small subset of leukemia stem cell (LSC), which presents unrestricted self-renewal and proliferation. Long non-coding RNA HOTAIR is abundantly expressed and plays oncogenic roles in solid cancer and AML. However, whether HOTAIR regulates the self-renewal of LSC is largely unknown. Here, we reported that the expression of HOTAIR was increased in LSC than in normal hematological stem and progenitor cells (HSPCs). HOTAIR inhibition by short hairpin RNAs (shRNAs) decreased colony formation in leukemia cell lines and primary AML blasts. We then investigated the role of HOTAIR in leukemia in vivo. HOTAIR knockdown extends the survival time in U937-transplanted NSG mice. Furthermore, HOTAIR knockdown reduced infiltration of leukemic blasts, decreased frequency of LSC, and prolonged overall survival in MLL-AF9-induced murine leukemia, suggesting that HOTAIR is required for the maintenance of AML. Mechanistically, HOTAIR inhibited p15 expression through zeste homolog 2 (EZH2)-enrolled tri-methylation of Lys 27 of histone H3 (H3K27me3) in p15 promoter. In addition, p15 partially reversed the decrease of colony and proliferation induced by HOTAIR knockdown, suggesting that p15 plays an important role in the leukemogenesis by HOTAIR. In conclusion, our study suggests that HOTAIR facilitates leukemogenesis by enhancing self-renewal of LSC. HOTAIR might be a potential target for anti-LSC therapy.

Long noncoding RNAs and their epigenetic function in hematological diseases

Recent discoveries demonstrate the importance of long noncoding RNA (lncRNA) in the regulation of multiple major processes impacting development, differentiation, and metastasis of hematological diseases through epigenetic mechanisms. In contrast to genetic changes, epigenetic modification does not modify genes but is frequently reversible, thus providing opportunities for targeted treatment using specific inhibitors. In this review, we will summarize the function and epigenetic mechanism of lncRNA in malignant hematologic diseases.

Aberrant mannosylation profile and FTX/miR-342/ALG3-axis contribute to development of drug resistance in acute myeloid leukemia

Drug-resistance is a major problem in acute myeloid leukemia (AML) chemotherapy. Aberrant changes in specific N-glycans have been observed in leukemia multidrug resistance (MDR). MicroRNAs (miRNAs) and long non coding RNAs (lncRNAs) act as key players in the development of AML resistance to chemotherapy. In the present study, the N-glycan profiles of membrane proteins were analyzed from adriamycin (ADR)-resistant U937/ADR cells and sensitive line U937 cells using mass spectrometry (MS). The composition profiling of high-mannose N-glycans differed in U937/ADR and U937 cell lines. Lectin microarray showed that the strong binding of membrane proteins was observed for MAN-M and ConA lectins, which were specific for mannose. These binding were also validated by flow cytometry. Importantly, the alteration of high-mannose N-glycan was further confirmed by detecting the enzyme level of ALG family. The altered level of ALG3 was found corresponding to the drug-resistant phenotype of AML cell lines both in vitro and in vivo. Mechanistically, miR-342 was found to be dysregulated and inversely correlated to ALG3 expression, targeting its 3'-UTR. LncRNA FTX was a direct target of miR-342 and positively modulated ALG3 expression by competitively binding miR-342 in AML cell lines. Functionally, we found that FTX directly interacted with miR-342 to regulate ALG3 expression and function, including ADR-resistant cell growth and apoptosis. The observation suggested that high-mannose N-glycans and mannosyltransferase ALG3 affected drug-resistance in AML cells. FTX/miR-342/ALG3 axis could potentially be used for the targets to overcome therapeutic resistance in AML.

Long non-coding RNA PVT1 activates hepatic stellate cells through competitively binding microRNA-152

Epithelial-mesenchymal transition (EMT) process is considered as a key event in the activation of hepatic stellate cells (HSCs). Hedgehog (Hh) pathway is known to be required for EMT process. Long non-coding RNAs (lncRNAs) have been reported to be involved in a wide range of biological processes. Plasmacytoma variant translocation 1 (PVT1), a novel lncRNA, is often up-regulated in various human cancers. However, the role of PVT1 in liver fibrosis remains undefined. In this study, PVT1 was increased in fibrotic liver tissues and activated HSCs. Depletion of PVT1 attenuated collagen deposits in vivo. In vitro, PVT1 down-regulation inhibited HSC activation including the reduction of HSC proliferation, α-SMA and type I collagen. Further studies showed that PVT1 knockdown suppressed HSC activation was through inhibiting EMT process and Hh pathway. Patched1 (PTCH1), a negative regulator factor of Hh pathway, was enhanced by PVT1 knockdown. PTCH1 demethylation caused by miR-152 was responsible for the effects of PVT1 knockdown on PTCH1 expression. Notably, miR-152 inhibitor reversed the effects of PVT1 knockdown on HSC activation. Luciferase reporter assays and pull-down assays showed a direct interaction between miR-152 and PVT1. Collectively, we demonstrate that PVT1 epigenetically down-regulates PTCH1 expression via competitively binding miR-152, contributing to EMT process in liver fibrosis.

LncRNA HOTAIR acts a competing endogenous RNA to control the expression of notch3 via sponging miR-613 in pancreatic cancer

Pancreatic cancer is one of the most deadly cancers with a poor prognosis. Though studies have implicated the roles of microRNAs in pancreatic cancer progression, little is known about the role of miR-613 in pancreatic cancer. In the present study, the expression of miR-613 was down-regulated in pancreatic cancer tissues and cancer cell lines. Down-regulation of miR-613 was positively correlated with tumor differentiation, advanced TNM stage, nodal metastasis and shorter overall survival in patients with pancreatic cancer. Overexpression of miR-613 suppressed cell proliferation, invasion and migration, and induced cell apoptosis and cell cycle arrest at G0/G1 phase in pancreatic cancer cells. Bioinformatics analysis, luciferase reporter assay and rescue experiments showed that notch3 was a direct target of miR-613. MiR-613 was inversely correlated with notch3 expression in pancreatic cancer tissues. The long non-coding RNA, HOX transcript antisense RNA (HOTAIR) was up-regulated in both pancreatic cancer tissues and cancer cell lines, and HOTAIR suppressed the expression of miR-613 via functioning as a competing endogenous RNA. In vivo studies showed that stable overexpression of miR-613 or knock-down of HOTAIR suppressed tumor growth and also reduced the expression of notch3. In conclusion, these results suggest that HOTAIR functions as a competing endogenous RNA to regulate notch3 expression via sponging miR-613 in pancreatic cancer.

[ARTICLE WITHDRAWN] Long Noncoding RNA MEG3 Inhibits Cell Proliferation and Metastasis in Chronic Myeloid Leukemia via Targeting miR-184

THIS ARTICLE WAS WITHDRAWN BY THE PUBLISHER IN 03/2021. We submitted a manuscript entitled "Long Noncoding RNA MEG3 Inhibits Cell Proliferation and Metastasis in Chronic Myeloid Leukemia via Targeting miR-184", which was published in the 26(2) issue of Oncology Research. But now we found some inaccuracies in this manuscript. So after carefully thinking, we are going to withdraw manuscript and try to give more precise model. Thus we decided to withdraw this manuscript with great pity. We sincerely say sorry for all the staffs involved this manuscript because of our action. All authors agree to withdraw this manuscript. Thank you very much for your time and kind consideration. Thanks for your time and best wishes. Li Jingdong.

HOTAIR contributes to cell proliferation and metastasis of cervical cancer via targetting miR-23b/MAPK1 axis

The long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) has been found to be overexpressed in many human malignancies and involved in tumor progression and metastasis. Although the downstream target through which HOTAIR modulates tumor metastasis is not well-known, evidence suggests that miR-23b might be involved in this event. In the present study, the expressions of HOTAIR and miR-23b were detected by real-time PCR in 33 paired cervical cancer tissue samples and cervical cell lines. The effects of HOTAIR on the expressions of miR-23b and mitogen-activated protein kinase 1 (MAPK1) were studied by overexpression and RNAi approaches. We found that HOTAIR expression was significantly increased in cervical cancer cells and tissues. In contrast, the expression of miR-23b was obviously decreased. We further demonstrated that HOTAIR knockdown promoted apoptosis and inhibited cell proliferation and invasion in vitro and in vivo. Moreover, our data indicated that HOTAIR may competitively bind miR-23b and modulate the expression of MAPK1 indirectly in cervical cancer cells. Taken together, our study has identified a novel pathway through which HOTAIR exerts its oncogenic role, and provided a molecular basis for potential applications of HOTAIR in the prognosis and treatment of cervical cancer.

Insights into the roles of lncRNAs in skeletal and dental diseases

Long noncoding RNAs (lncRNAs) are a class of non-protein-coding transcripts with the length longer than 200 nucleotides. Growing evidence suggests that lncRNAs, which were initially thought to be merely transcriptional “noise”, participate in a wide repertoire of biological processes. It has been well established that lncRNAs not only play important roles in genomic regulation, transcription, posttranscriptional processes but are also implicated in the pathogenesis of human diseases including cardiovascular diseases, diabetes, neurodegenerative disorders, and cancer. However, the pathological role of lncRNAs in skeletal and dental diseases is just beginning to be uncovered. In the present review, we outline the current understanding of the established functions and underlying mechanisms of lncRNAs in various cellular processes. Furthermore, we discuss new findings on the role of lncRNAs in osteoblastogenesis and osteoclastogenesis as well as their involvement in skeletal and dental diseases. This review intends to provide a general framework for the actions of lncRNAs and highlight the emerging evidence for the functions of lncRNAs in skeletal and dental diseases.

MicroRNAs as New Biomarkers for Diagnosis and Prognosis, and as Potential Therapeutic Targets in Acute Myeloid Leukemia

Acute myeloid leukemias (AML) are clonal disorders of hematopoietic progenitor cells which are characterized by relevant heterogeneity in terms of phenotypic, genotypic, and clinical features. Among the genetic aberrations that control disease development there are microRNAs (miRNAs). miRNAs are small non-coding RNAs that regulate, at post-transcriptional level, translation and stability of mRNAs. It is now established that deregulated miRNA expression is a prominent feature in AML. Functional studies have shown that miRNAs play an important role in AML pathogenesis and miRNA expression signatures are associated with chemotherapy response and clinical outcome. In this review we summarized miRNA signature in AML with different cytogenetic, molecular and clinical characteristics. Moreover, we reviewed the miRNA regulatory network in AML pathogenesis and we discussed the potential use of cellular and circulating miRNAs as biomarkers for diagnosis and prognosis and as therapeutic targets.

Impact of HOTAIR Gene Polymorphism and Environmental Risk on Oral Cancer

Genetic and acquired factors are thought to be interrelated and imperative to estimate the risk and prognosis of oral squamous cell carcinoma (OSCC). HOX transcript antisense intergenic RNA ( HOTAIR) plays crucial roles in gene regulation and is regulated in a variety of cancers. Polymorphisms in HOTAIR have been recently linked to the predisposition to diverse malignancies. In the present study, we aimed to evaluate the influences of HOTAIR gene polymorphisms, combined with environmental triggers, on the susceptibility to oral tumorigenesis. Four single-nucleotide polymorphisms of the HOTAIR gene— rs920778, rs1899663, rs4759314, and rs12427129—were tested in 1,200 control participants and 907 patients with OSCC. We detected a significant association of rs1899663 with the risk of OSCC (adjusted odds ratio, 2.227; 95% confidence interval [95% CI], 1.197 to 4.146; P = 0.012) after adjustment for 3 potential confounders: smoking, betel quid chewing, and alcohol consumption. In further analyses where habitual exposure to each of 3 environmental factors was excluded, we found that, in addition to rs1899663, non–betel quid users who carried the polymorphic allele of rs920778 were more prone to develop OSCC than were those homozygous for wild-type allele (TC: odds ratio [OR], 1.472; 95% CI, 1.069 to 2.029; P = 0.018; TC+CC: OR, 1.448; 95% CI, 1.060 to 1.977; P = 0.020). Moreover, in exploring the relationship between HOTAIR gene polymorphisms and the clinical status of only patients with OSCC who were non–betel quid chewers (excluding the advanced clinical stage), we found that rs920778 and rs4759314 were correlated with the development of large-size tumors (OR, 1.891; 95% CI, 1.027 to 3.484; P = 0.04) and increased lymph node metastasis (OR, 4.140; 95% CI, 1.785 to 9.602; P = 0.001), respectively. Further functional assessments link rs920778 to the regulation of HOTAIR expression and epigenetic status. Our results reveal an interactive effect of HOTAIR gene polymorphisms and betel quid chewing on the development and progression of oral cancer.

LncRNA HIF1A-AS2 positively affects the progression and EMT formation of colorectal cancer through regulating miR-129-5p and DNMT3A

LncRNAs were a group of RNAs, which can be a regulator or master in biological activities of cancer cells. HIF1A-AS2 belongs to this group, and it has been verified to be able to affect cell activities in several kinds of cancers. In this study, we tried to study the functions of HIF1A-AS2 exerted in colorectal cancer. In order to clearly know about the expression of HIF1A-AS2, miR-129-5p and DNMT3A in CRC tissues and cells, we employed qRT-PCR. The relevance among those three genes was examined by the use of Pearson correlation analysis. With the aid of bioinformatics analysis and dual luciferase reporter assays, the combinations between them were verified one by one MTT, colony formation trans-well and western blotting, immunofluorescence, all those assays reflected a fact that as a ceRNA, HIF1A-AS2 could directly bind with miR-129-5p, and could positively affect cell proliferation, invasion and EMT formation by regulation of the expression of miR-129-5p and DNMT3A. Therefore, we obtained a conclusion that HIF1A-AS2 exerted the oncogenic functions in CRC through regulating miR-129-5p/DNMT3A axis, which indicates that HIF1A-AS2 might be a useful therapeutic target in CRC.

Long non-coding RNA PAX8-AS1 polymorphisms increase the risk of childhood acute lymphoblastic leukemia

The present case-control study was conducted on 110 children with acute lymphoblastic leukemia (ALL) and 120 healthy children to determine the impact of polymorphisms in paired-box gene 8 (PAX8) antisense RNA 1 (PAX8-AS1), namely rs4848320 C>T, rs6726151 T>G and rs1110839 G>T, on ALL risk. Genotyping was performed through the polymerase chain reaction-restriction fragment length polymorphism method. The findings indicated that the rs4848320 variant increased the risk of ALL in codominant [CT vs. CC: odds ratio (OR)=2.13, 95% confidence interval (CI)=1.16-3.90, P=0.014; and TT vs. CC: OR=2.21, 95% CI=1.03-4.74, P=0.041], dominant (CT+TT vs. CC: OR=2.15, 95% CI=1.22-3.81, P=0.009,) and allele (T vs. C: OR=1.55, 95% CI=1.07-2.25, P=0.024) inheritance models. The rs6726151 variant significantly increased the risk of ALL in codominant (GT vs. GG: OR=1.88, 95% CI=1.08-3.27, P=0.036) and overdominant (GT vs. GG+TT: OR=2.08, 95% CI=1.23-3.53, P=0.008) inheritance models. No significant relationship was identified between the rs1110839 G>T variant and disease risk/protection in childhood ALL. In conclusion, the findings of the present study indicated that rs4848320 and rs6726151 polymorphisms of PAX8-AS1 may be a risk factor for the development of childhood ALL. Further studies with larger sample sizes and different ethnicities are now required to confirm these findings.

The involvement of lncRNAs in the development and progression of pancreatic cancer

Pancreatic cancer is one of the most malignant tumors that are difficult to diagnose at its early stage and there is no effective therapy. Recent studies uncovered that many non-protein-coding RNAs including the class of long noncoding RNAs (lncRNAs) are differentially expressed in various types of tumors and they are potent regulators of tumor progression and metastasis. LncRNA can mediate tumor initiation, proliferation, migration and metastasis through modulating epigenetic modification, alternative splicing, transcription, and protein translation. In this review, we discuss the molecular mechanism of lncRNAs in the involvement of tumor growth, survival, epithelial-mesenchymal transition, tumor microenvironment, cancer stem cells and chemoresistance in pancreatic ductal adenocarcinoma (PDAC).

The Long Noncoding RNA HOTAIR Promotes Colorectal Cancer Progression by Sponging miR-197

The long noncoding RNA HOX transcript antisense RNA (HOTAIR) has been found to be overexpressed in many human malignancies and involved in tumor progression and metastasis. Although the downstream target through which HOTAIR modulates tumor metastasis is not well known, evidence suggests that microRNA-197 (miR-197) might be involved in this event. In the present study, the significance of HOTAIR and miR-197 in the progression of colorectal cancer was detected in vitro and in vivo. We found that HOTAIR expression was significantly increased in colorectal cancer cells and tissues. In contrast, the expression of miR-197 was obviously decreased. We further demonstrated that HOTAIR knockdown promoted apoptosis and inhibited cell proliferation, migration, and invasion in vitro and in vivo. Moreover, HOTAIR modulated the progression of colorectal cancer by competitively binding miR-197. Taken together, our study has identified a novel pathway through which HOTAIR exerts its oncogenic role and provided a molecular basis for potential applications of HOTAIR in the prognosis and treatment of colorectal cancer.

microRNAs and Acute Myeloid Leukemia Chemoresistance: A Mechanistic Overview

Up until the early 2000s, a functional role for microRNAs (miRNAs) was yet to be elucidated. With the advent of increasingly high-throughput and precise RNA-sequencing techniques within the last two decades, it has become well established that miRNAs can regulate almost all cellular processes through their ability to post-transcriptionally regulate a majority of protein-coding genes and countless other non-coding genes. In cancer, miRNAs have been demonstrated to play critical roles by modifying or controlling all major hallmarks including cell division, self-renewal, invasion, and DNA damage among others. Before the introduction of anthracyclines and cytarabine in the 1960s, acute myeloid leukemia (AML) was considered a fatal disease. In decades since, prognosis has improved substantially; however, long-term survival with AML remains poor. Resistance to chemotherapy, whether it is present at diagnosis or induced during treatment is a major therapeutic challenge in the treatment of this disease. Certain mechanisms such as DNA damage response and drug targeting, cell cycling, cell death, and drug trafficking pathways have been shown to be further dysregulated in treatment resistant cancers. miRNAs playing key roles in the emergence of these drug resistance phenotypes have recently emerged and replacement or inhibition of these miRNAs may be a viable treatment option. Herein, we describe the roles miRNAs can play in drug resistant AML and we describe miRNA-transcript interactions found within other cancer states which may be present within drug resistant AML. We describe the mechanisms of action of these miRNAs and how they can contribute to a poor overall survival and outcome as well. With the precision of miRNA mimic- or antagomir-based therapies, miRNAs provide an avenue for exquisite targeting in the therapy of drug resistant cancers.

NEAT1 accelerates the progression of liver fibrosis via regulation of microRNA-122 and Kruppel-like factor 6

Long non-coding RNAs (lncRNAs) have been reported to be involved in many important biological processes including proliferation, apoptosis, differentiation, and survival. Recently, nuclear paraspeckle assembly transcript 1 (NEAT1), a novel lncRNA, serves as a crucial regulator in tumors. However, the biological role of NEAT1 in liver fibrosis is largely unknown. In this study, the role of NEAT1 was explored in primary mouse hepatic stellate cells (HSCs) and carbon tetrachloride (CCl₄)-induced mouse liver fibrosis models. We found that NEAT1 expression was significantly increased in CCl₄-induced mice and activated HSCs. Loss of NEAT1 suppressed liver fibrosis in vivo and in vitro. Conversely, NEAT1 overexpression accelerated HSC activation, including increased cell proliferation and collagen expression. Further studies indicated that the microRNA-122 (miR-122)-Kruppel-like factor 6 (KLF6) axis was involved in the effects of NEAT1 on HSC activation. The effects of NEAT1 on HSC activation were almost blocked down by miR-122 mimics or KLF6 knockdown. Interestingly, both NEAT1 and KLF6 are targets of miR-122. In addition, miR-122 led to a significant reduction in NEAT1 level while NEAT1 overexpression resulted in the suppression of miR-122 expression. Pull-down assay confirmed a direct interaction between miR-122 and NEAT1. NEAT1 contributes to HSC activation via the miR-122-KLF6 axis. In human fibrotic liver samples, increased NEAT1 levels positively correlated with liver fibrosis markers. In conclusion, we disclose a novel NEAT1-miR-122-KLF6 signaling cascade and its implication in liver fibrosis.

KEY MESSAGES

NEAT1 was significantly increased in CCl₄-induced mice and activated HSCs. Loss of NEAT1 suppressed liver fibrosis in vivo and in vitro. KLF6 and miR-122 were required for the effects of NEAT1 on HSC activation. NEAT1 contributes to HSC activation via competitively binding miR-122. We disclose a novel NEAT1-miR-122-KLF6 signaling cascade.

A 4-lncRNA scoring system for prognostication of adult myelodysplastic syndromes

Long noncoding RNAs (lncRNAs) not only participate in normal hematopoiesis but also contribute to the pathogenesis of acute leukemia. However, their clinical and prognostic relevance in myelodysplastic syndromes (MDSs) remains unclear to date. In this study, we profiled lncRNA expressions in 176 adult patients with primary MDS, and identified 4 lncRNAs whose expression levels were significantly associated with overall survival (OS). We then constructed a risk-scoring system with the weighted sum of these 4 lncRNAs. Higher lncRNA scores were associated with higher marrow blast percentages, higher-risk subtypes of MDSs (based on both the Revised International Prognostic Scoring System [IPSS-R] and World Health Organization classification), complex cytogenetic changes, and mutations in RUNX1, ASXL1, TP53, SRSF2, and ZRSR2, whereas they were inversely correlated with SF3B1 mutation. Patients with higher lncRNA scores had a significantly shorter OS and a higher 5-year leukemic transformation rate compared with those with lower scores. The prognostic significance of our 4-lncRNA risk score could be validated in an independent MDS cohort. In multivariate analysis, higher lncRNA scores remained an independent unfavorable risk factor for OS (relative risk, 4.783; P < .001) irrespective of age, cytogenetics, IPSS-R, and gene mutations. To our knowledge, this is the first report to provide a lncRNA platform for risk stratification of MDS patients. In conclusion, our integrated 4-lncRNA risk-scoring system is correlated with distinctive clinical and biological features in MDS patients, and serves as an independent prognostic factor for survival and leukemic transformation. This concise yet powerful lncRNA-based scoring system holds the potential to improve the current risk stratification of MDS patients.

miR-92a Inhibits Proliferation and Induces Apoptosis by Regulating Methylenetetrahydrofolate Dehydrogenase 2 (MTHFD2) Expression in Acute Myeloid Leukemia

Aberrant expression of microRNA-92a (miR-92a) has been investigated in various cancers. However, the function and mechanism of miR-92a in acute myeloid leukemia (AML) remain to be elucidated. Our data showed that miR-92a was evidently downregulated and methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) was remarkably upregulated in AML cell lines HL-60 and THP-1. Dual luciferase reporter assay revealed that MTHFD2 was a direct target of miR-92a. Gain- and loss-of-function analysis demonstrated that MTHFD2 knockdown or miR-92a overexpression notably inhibited proliferation and promoted apoptosis of AML cell lines. Restoration of MTHFD2 expression reversed proliferation inhibition and apoptosis induction of AML cells triggered by miR-92a. Moreover, an implanted tumor model in mice indicated that miR-92a overexpression dramatically decreased tumor growth and MTHFD2 expression in vivo. Taken together, our results suggest that miR-92a inhibits proliferation and induces apoptosis by directly regulating MTHFD2 expression in AML. miR-92a may act as a tumor suppressor in AML, providing a promising therapeutic target for AML patients.

MicroRNAs and acute myeloid leukemia: therapeutic implications and emerging concepts

Acute myeloid leukemia (AML) is a deadly hematologic malignancy characterized by the uncontrolled growth of immature myeloid cells. Over the past several decades, we have learned a tremendous amount regarding the genetic aberrations that govern disease development in AML. Among these are genes that encode noncoding RNAs, including the microRNA (miRNA) family. miRNAs are evolutionarily conserved small noncoding RNAs that display important physiological effects through their posttranscriptional regulation of messenger RNA targets. Over the past decade, studies have identified miRNAs as playing a role in nearly all aspects of AML disease development, including cellular proliferation, survival, and differentiation. These observations have led to the study of miRNAs as biomarkers of disease, and efforts to therapeutically manipulate miRNAs to improve disease outcome in AML are ongoing. Although much has been learned regarding the importance of miRNAs in AML disease initiation and progression, there are many unanswered questions and emerging facets of miRNA biology that add complexity to their roles in AML. Moving forward, answers to these questions will provide a greater level of understanding of miRNA biology and critical insights into the many translational applications for these small regulatory RNAs in AML.

HOTAIR Long Noncoding RNA is not a Biomarker for Acute Myeloid Leukemia (AML) in Iranian Patients

Accumulating evidence indicates that lncRNAs may have potential as new biomarkers to predict prognosis of different human cancers. HOTAIR lncRNA, transcribed from the human HOX locus, has been suggested to regulate gene expression of important target genes and up-regulation has been noted in malignancies. The role of HOX transcript antisense RNA in acute myeloid leukemia (AML) was investigated in the present case control study. HOTAIR expression was evaluated in blood samples of twenty five de novo AML patients and fifty healthy controls using real-time quantitative reverse transcription-PCR (qRT-PCR). Our results demonstrated no significant differences in HOTAIR lncRNA expression level between AML patients and healthy individuals. The obtained data indicate that HOTAIR is not an informative and reliable biomarker for AML diagnosis, although our results should be confirmed in further studies.

HOTAIR: a key regulator in gynecologic cancers

Long non-coding RNAs (lncRNAs) play critical roles in the initiation and progression of human cancers. HOX transcript antisense RNA (HOTAIR) is an lncRNA localized to the mammalian HOXC gene cluster; it can interact with polycomb repressive complex 2 and the lysine-specific histone demethylase/CoREST/REST complex, and it manipulates the expression of various genes. HOTAIR promotes tumor invasion and metastasis by silencing tumor suppressors, and activating oncogenes and signaling pathways. HOTAIR is deregulated in many human cancers; despite its critical roles in health and disease, the underlying mechanisms governing HOTAIR function are unknown. In this review, we summarize the recent findings on the roles of HOTAIR in gynecologic cancers.

Role of the long non-coding RNA HOTAIR in hepatocellular carcinoma

A number of recent studies have focused on the association between long non-coding RNAs (lncRNAs) and cancer. HOX transcript antisense RNA (HOTAIR), an lncRNA that functions as a transcriptional modulator, has been implicated in various fundamental biological activities. HOTAIR mediates the trimethylation of histone H3 at lysine 27 and the demethylation of histone H3 dimethyl Lys4 by recruiting the polycomb repressive complex 2 and the lysine-specific demethylase 1/co-repressor of RE1-silencing transcription factor (coREST)/REST complex to the target gene promoters, which leads to gene silencing. Overexpression of HOTAIR in hepatocellular carcinoma (HCC) is strongly associated with an unfavorable prognosis for patients with HCC. HOTAIR promotes the carcinogenic activity of HCC cells through the suppression of RNA binding motif protein 38, triggering the epithelial-mesenchymal transition, and by interacting with microRNAs that act as tumor suppressors. In the present review, the role of the lncRNA HOTAIR in HCC is examined. The potential use of HOTAIR as a biomarker to achieve more accurate prognostic predictions and as an effective therapeutic target for HCC is then discussed.

Overexpression of long non-coding RNA zinc finger antisense 1 in acute myeloid leukemia cell lines influences cell growth and apoptosis

The association between long non-coding RNA zinc finger antisense 1 (ZFAS1) and acute myeloid leukemia (AML) has not yet been investigated. The present study aimed to assess the potential role of ZFAS1 in AML cell proliferation and apoptosis. The expression of ZFAS1 mRNA in various AML cell lines (HL-60, KG-1, ML-1 and SKNO-1) was measured by reverse transcription-quantitative polymerase chain reaction. The results showed that ZFAS1 expression was increased in all four human AML cell lines compared with the control cell lines (T lymphocytic leukemia or Burkitt's lymphoma). Transfection with small interfering RNA into human AML cells established ZFAS1 knockdown. A cell-counting kit-8 (CCK-8) assay was used to investigate the effect of ZFAS1 on AML cell proliferation and the effect of ZFAS1 on the cell cycle and cell apoptosis was assessed using flow cytometry. Notably, the CCK-8 assay demonstrated that ZFAS1 knockdown inhibited cell proliferation in HL-60 and SKNO-1 cell lines and flow cytometry analysis indicated that ZFAS1 knockdown induced AML cell cycle G1 phase arrest and triggered cell apoptosis. Therefore, the present study indicated that ZFAS1 promoted the proliferation and inhibited the apoptosis of AML cells.

RNA-binding protein HuR promotes bladder cancer progression by competitively binding to the long noncoding HOTAIR with miR-1

The elevated expressions of RNA-binding protein HuR and long noncoding HOX transcript antisense RNA (HOTAIR) are observed in numerous cancers. And HuR often exerts its promotive effects on tumorigenesis via binding to AU-rich elements in target transcripts and thus regulating the expression of target transcripts. However, the roles and related mechanisms of HuR/HOTAIR in bladder cancer progression have never been formally tested. Here, we found that the expression level of HuR was higher in clinical bladder cancer samples than in normal adjacent samples, mirroring that of HOTAIR, and their expression showed strong correlation. Knockdown of HuR/HOTAIR in bladder cancer inhibited cell proliferation, migration, invasion, and promoted cell apoptosis. Notably, HuR interacted and stabilized HOTAIR mRNA and knockdown of HuR decreased HOTAIR expression. Additionally, HOTAIR was identified as a potential target of miR-1 in bladder cancer cells. Interestingly, overexpression of HOTAIR enhanced HuR expression and increased cytoplasmic accumulation of HuR, thus enhancing HOTAIR expression in turn. But mutation of miR-1 binding site in HOTAIR canceled the effects of HOTAIR on HuR expression. Overall, we identified a regulatory loop between HOTAIR and HuR during the progression of bladder cancer, which could be exploited to curb bladder cancer progression.

LncRNA XIST Promotes Pancreatic Cancer Proliferation Through miR-133a/EGFR

According to recent studies, long non-coding RNA X-inactive specific transcript (XIST) is involved in the development and progression of many malignant tumors including pancreatic cancer. We validated the detailed role of XIST in human pancreatic cancer (PC) cell lines and PC tissues so as to determine its exact function and the mechanism by which it affected PC proliferation. In our research, lncRNA-XIST was specifically upregulated in PC tissues and cell lines, and high XIST expression in PC was related to poorer prognosis (larger tumor size, perineural invasion, lymph node micrometastases, and shorter overall survival). XIST augmented PC cell proliferation. Recently, the interaction between lncRNA and miRNA has been frequently reported to play major role in several biological processes. In the present study, XIST and miR-133a reciprocally inhibited each other in PC cells. Exogenous miR-133a expression significantly inhibited PC cell proliferation. Moreover, as exhibited by luciferase reporter gene assays, miR-133a bound to XIST and the 3'UTR of EGFR by direct targeting. In PC tissues, miR-133a expression was down-regulated and EGFR expression was up-regulated; miR-133a was inversely correlated with EGFR and XIST, respectively; XIST was positively correlated with EGFR. Taken together, these findings will shed light on the role and mechanism of XIST/miR-133a/EGFR in regulating PC cells proliferation. XIST may serve as a potential therapeutic target in PC in the future. J. Cell. Biochem. 118: 3349-3358, 2017. © 2017 Wiley Periodicals, Inc.

Emerging genotype-phenotype relationships in patients with large NF1 deletions

The most frequent recurring mutations in neurofibromatosis type 1 (NF1) are large deletions encompassing the NF1 gene and its flanking regions (NF1 microdeletions). The majority of these deletions encompass 1.4-Mb and are associated with the loss of 14 protein-coding genes and four microRNA genes. Patients with germline type-1 NF1 microdeletions frequently exhibit dysmorphic facial features, overgrowth/tall-for-age stature, significant delay in cognitive development, large hands and feet, hyperflexibility of joints and muscular hypotonia. Such patients also display significantly more cardiovascular anomalies as compared with patients without large deletions and often exhibit increased numbers of subcutaneous, plexiform and spinal neurofibromas as compared with the general NF1 population. Further, an extremely high burden of internal neurofibromas, characterised by >3000 ml tumour volume, is encountered significantly, more frequently, in non-mosaic NF1 microdeletion patients than in NF1 patients lacking such deletions. NF1 microdeletion patients also have an increased risk of malignant peripheral nerve sheath tumours (MPNSTs); their lifetime MPNST risk is 16-26%, rather higher than that of NF1 patients with intragenic NF1 mutations (8-13%). NF1 microdeletion patients, therefore, represent a high-risk group for the development of MPNSTs, tumours which are very aggressive and difficult to treat. Co-deletion of the SUZ12 gene in addition to NF1 further increases the MPNST risk in NF1 microdeletion patients. Here, we summarise current knowledge about genotype-phenotype relationships in NF1 microdeletion patients and discuss the potential role of the genes located within the NF1 microdeletion interval whose haploinsufficiency may contribute to the more severe clinical phenotype.

HOTAIR Epigenetically Modulates PTEN Expression via MicroRNA-29b: A Novel Mechanism in Regulation of Liver Fibrosis

Homeobox transcript antisense RNA (HOTAIR), as a long intergenic non-coding RNA (lincRNA), is upregulated in various cancers and involved in diverse cellular functions. However, its role in liver fibrosis is unclear. In this study, HOTAIR expression was upregulated in hepatic stellate cells (HSCs) in vivo and in vitro during liver fibrosis. HOTAIR knockdown suppressed HSC activation including α-smooth muscle actin (α-SMA) and typeIcollagen in vitro and in vivo. Both HSC proliferation and cell cycle were inhibited by HOTAIR knockdown. Notably, inhibition of HOTAIR led to an increase in PTEN, associated with the loss of DNA methylation. miR-29b-mediated control of PTEN methylation was involved in the effects of HOTAIR knockdown. HOTAIR was confirmed a target of miR-29b and lack of the miR-29b binding site in HOTAIR prevented the suppression of miR-29b, suggesting HOTAIR contributes to PTEN expression downregulation via sponging miR-29b. Interestingly, increased HOTAIR was also observed in hepatocytes during liver fibrosis. Loss of HOTAIR additionally led to the increase in PTEN and the reduction in typeIcollagen in hepatocytes. Collectively, we demonstrate that HOTAIR downregulates miR-29b expression and attenuates its control on epigenetic regulation, leading to enhanced PTEN methylation, which contributes to the progression of liver fibrosis.

Long noncoding RNAs: pivotal regulators in acute myeloid leukemia

Long noncoding RNAs (lncRNAs) have emerged as a class of pivotal regulators of gene expression. Recent studies have shown that lncRNAs contribute to the initiation, maintenance, and development of acute myeloid leukemia (AML). In this review, we summarize the current knowledge of the lncRNAs that play critical roles in AML. We first briefly describe the characteristics of lncRNAs, and then focus on their regulatory roles in AML, including the modulation of differentiation, proliferation, cell cycle, and apoptosis. We further emphasize the action of lncRNAs during leukemogenesis by describing how they interact with RNA, protein and chromatin DNA to exert their functions. We also highlight an urgent need to investigate the mechanisms by which lncRNAs contribute to the pathogenesis of AML. Finally, we discuss the prognostic value of lncRNAs in AML patients.

Therapeutic Resistance in Acute Myeloid Leukemia: The Role of Non-Coding RNAs

Acute myeloid leukemia (AML) is caused by malignant transformation of hematopoietic stem or progenitor cells and displays the most frequent acute leukemia in adults. Although some patients can be cured with high dose chemotherapy and allogeneic hematopoietic stem cell transplantation, the majority still succumbs to chemoresistant disease. Micro-RNAs (miRNAs) and long non-coding RNAs (lncRNAs) are non-coding RNA fragments and act as key players in the regulation of both physiologic and pathologic gene expression profiles. Aberrant expression of various non-coding RNAs proved to be of seminal importance in the pathogenesis of AML, as well in the development of resistance to chemotherapy. In this review, we discuss the role of miRNAs and lncRNAs with respect to sensitivity and resistance to treatment regimens currently used in AML and provide an outlook on potential therapeutic targets emerging thereof.

Association of lnc-LAMC2-1:1 rs2147578 and CASC8 rs10505477 Polymorphisms with Risk of Childhood Acute Lymphoblastic Leukemia

Long non-coding RNAs (lncRNAs) are a novel class of non-protein coding RNAs that are involved in a wide variety of biological processes. There are limited data regarding the impact of lnc-LAMC2-1:1 rs2147578 as well as CASC8 rs10505477 T>C polymorphisms on cancer development. Here we examined for the first time whether rs2147578 and rs10505477 polymorphisms are associated with childhood acute lymphoblastic leukemia (ALL) in a total of 110 cases and 120 healthy controls. Genotyping was achieved by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The rs2147578 variant increased the risk of ALL in codominant (OR=4.33, 95%CI=2.00-9.37, p<0.0001, CG vs CC, and OR=5.81, 95%CI=2.30-14.69, p=0.0002, GG vs CC), dominant (OR=4.63, 95%CI=2.18-9.86, p<0.0001, CG+GG vs CC), overdominant (OR=1.74, 95%CI=1.02-2.97, p=0.0444, CG vs CC+GG) and allele (OR=1.91, 95%CI=1.32-2.77, p=0.0008, G vs C) inheritance models tested. No significant association was found between the CASC8 rs10505477 T>C variant and risk of childhood ALL. In conclusion, the present study revealed that the lnc-LAMC2-1:1 rs2147578 polymorphism may be a risk factor for developing childhood ALL. Further studies with larger sample sizes with different ethnicities are now required to confirm our findings.

MicroRNA 4323 induces human bladder smooth muscle cell proliferation under cyclic hydrodynamic pressure by activation of erk1/2 signaling pathway

We cultivated human bladder smooth muscle cells (HBSMCs) under pressures of 0 or 200 cm H₂O pressure for 24 h, before using microarray technology to extract and analyze the different expressions of miRNAs and mRNAs in the two groups. We also predicted the target mRNA of the miDNA and performed functional forecasting. Changes in miRNA were identified by quantitative real-time polymerase chain reaction (qRT-PCR) after overexpressing miRNA by transfection. We used flow cytometry to examine HBSMC proliferation, and we used qRT-PCR and Western blot analyses to quantify the expression and activation of mRNAs and proteins. There were nine upregulated and four downregulated miRNAs involved in cell proliferation, including miR 4323, which was identified by qRT-PCR ( p = 0.027). In addition, miR 4323 was shown to inhibit LYN ( p = 0.031), decrease lyn kinase ( p = 0.037), and promotes the phosphorylation of extracellular regulated protein kinases 1 and 2 (Erk1/2) ( p = 0.004). Moreover, overexpression of miR 4323 activated the proliferation pathway regulated by Erk1/2. Then, miR 4323 was shown to stimulate the proliferation of HBSMCs, with the proliferation index improving from 30.84 ± 4.57 to 52.13 ± 3.41 ( p = 0.001). In summary, when the miRNA miR 4323 was overexpressed under cyclic hydrodynamic pressure, LYN is decreased and the Erk1/2 signaling pathway is activated; in addition, miR 4323 is involved in HBSMC proliferation when under hydrodynamic pressure.

MiR 3180-5p promotes proliferation in human bladder smooth muscle cell by targeting PODN under hydrodynamic pressure

Human bladder smooth muscle cells (HBSMCs) were subjected to pressure cycles of up to 200 cm H₂O to a pressure of 0 cm H₂O for 24 hours. The total RNA extracted from each group was subjected to microarray analysis. miR-3180-5p emerged as the most overexpressed of all the differentially expressed microRNAs, and this finding was validated by PCR. We then used CCK-8 to quantify cell proliferation after liposome-mediated transfection. Subsequently, we investigated the change in PODN and its downstream signaling proteins, including cyclin-dependent kinase 2 (cdk2) and p21. In addition, flow cytometry was performed to quantify cell-cycle distribution. The results show that miR-3180-5p, the microRNA that was most overexpressed in response to HP, reduced the expression of PODN and podocan (p = 0.004 and p = 0.041, respectively). Silencing of PODN via miR-3180-5p overexpression revealed a significant promotion of cell proliferation increased in the CCK-8 experiment, p = 0.00077). This cell proliferation was accompanied by an increase in cdk2 expression (p = 0.00193) and a decrease in p21 expression (p = 0.0095). The percentage of cells in (S + G2/M) improved after transfection (p = 0.002). It was apparent that HP upregulates miR-3180-5p, which inhibits the expression of PODN and promotes HBSMC proliferation via the cdk2 signaling pathway.

Long non-coding RNA HOTAIR modulates HLA-G expression by absorbing miR-148a in human cervical cancer

The long non-coding RNA HOX transcript antisense RNA (HOTAIR) has been found overexpressed in many human malignancies and involved in tumor progression and metastasis. However, little is known about the potential biological roles of HOTAIR in tumor escape. In the present study, the expression of HOTAIR was detected in 59 paired cervical cancer tissue samples by real-time PCR and then subjected to correlation analysis with clinical features. The effects of HOTAIR on cervical cancer cells as well as the expression of human leukocyte antigen (HLA)-G were studied by overexpression and RNA interference approaches. Insight into the mechanism of HOTAIR acting as competitive endogenous RNAs (ceRNAs) was gained from bioinformatic analysis and luciferase assays. HOTAIR expression was obviously increased in cervical cancer tissue. HOTAIR upregulation was associated with advanced pathological stage, histology, lymph node invasion and lymphatic metastasis, and also correlated with shorter overall survival of cervical cancer patients. Furthermore, HOTAIR overexpression promoted the proliferation, migration and invasion of cervical cancer cells, while HOTAIR knockdown inhibited cell invasion and cell viability, induced apoptosis and inhibited growth in vitro and in vivo. Moreover, HOTAIR modulated human leucocyte antigen-G (HLA-G) expression by competitively binding miR-148a. Our data suggest that HOTAIR plays an important oncogenic role in cervical cancer and might serve as a marker for cervical cancer prognosis and a potential target for therapeutic intervention.