Role of HOTAIR in the diagnosis and prognosis of acute leukemia

The biological role of lncRNAs in the acute lymphocytic leukemia: An updated review

The cause of leukemia, a common malignancy of the hematological system, is unknown. The structure of long non-coding RNAs (lncRNAs) is similar to mRNA but no ability to encode proteins. Numerous malignancies, including different forms of leukemia, are linked to Lnc-RNAs. It is verified that the carcinogenesis and growth of a variety of human malignancies are significantly influenced by aberrant lncRNA expression. The body of evidence linking various types of lncRNAs to the etiology of leukemia has dramatically increased during the past ten years. Some lncRNAs are therefore anticipated to function as novel therapeutic targets, diagnostic biomarkers, and clinical outcome predictions. Additionally, these lncRNAs may provide new therapeutic options and insight into the pathophysiology of diseases, particularly leukemia. Thus, this review outlines the present comprehension of leukemia-associated lncRNAs.

JMJD6-BRD4 complex stimulates lncRNA HOTAIR transcription by binding to the promoter region of HOTAIR and induces radioresistance in liver cancer stem cells

BACKGROUND

Long non-coding RNA (lncRNA) HOTAIR acts importantly in liver cancer development, but its effect on radioresistance remains poorly understood. Here, our study probed into the possible impact of HOTAIR in radioresistance in liver cancer stem cells (LCSCs) and to elucidate its molecular basis.

METHODS

Following sorting of stem and non-stem liver cancer cells, LCSCs were identified and subjected to RNA-seq analysis for selecting differentially expressed genes. Expression of HOTAIR was determined in liver cancer tissues and CSCs. The stemness, proliferation, apoptosis and radioresistance of LCSCs were then detected in response to altered expression of HOTAIR-LSD1-JMJD6-BRD4.

RESULTS

Ectopic HOTAIR expression was found to promote radioresistance of LCSCs by maintaining its stemness. Mechanistic investigations indicated that HOTAIR recruited LSD1 to the MAPK1 promoter region and reduced the level of H3K9me2 in the promoter region, thus elevating ERK2 (MAPK1) expression. JMJD6-BRD4 complex promoted HOTAIR transcription by forming a complex and positively regulated ERK2 (MAPK1) expression, maintaining the stemness of LCSCs, and ultimately promoting their radioresistance in vitro and in vivo.

CONCLUSION

Collectively, our work highlights the promoting effect of the JMJD6-BRD4 complex on the radioresistance of LCSCs through a HOTAIR-dependent mechanism.

Pathogenic Mechanisms in Acute Myeloid Leukemia

OPINION STATEMENT

Acute myeloid leukemia (AML) is the most common form of leukemia in adults, leading to the highest number of annual leukemia-associated deaths in the USA. Although most AML patients initially enter remission following induction therapy, most eventually relapse, underscoring the unmet need for more effective therapies. In recent years, novel high-throughput sequencing techniques, and mouse and human models of disease have increased our understanding of the molecular mechanisms that lead to AML. Leukemogenic mechanisms can be broadly classified into two types-cell-intrinsic and cell-extrinsic. Cell-intrinsic mechanisms include an array of genetic and epigenetic alterations that lead to dysregulated gene expression and function in hematopoietic stem/progenitor cells, leading to their increased fitness and ultimately, malignant transformation. Extrinsic mechanisms include both hematopoietic and non-hematopoietic stromal components of the leukemic microenvironment that interact with pre-leukemic and leukemic clones to promote their survival, self-renewal, and/or resistance to therapy. Through the individual and concerted action of these factors, pre-leukemic clones acquire the changes necessary for leukemic transformation. In addition, following therapy, specific leukemic clones are selected for that eventually re-initiate disease. Improving our understanding of these cell-intrinsic and cell-extrinsic mechanisms will provide novel opportunities to treat AML as well as prevent the development of disease.

Plasma lncRNA LOC338963 and mRNA AP3B2 are upregulated in paraneoplastic Lambert-Eaton myasthenic syndrome

INTRODUCTION/AIMS

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune neuromuscular junction disorder. Long noncoding RNA (lncRNA) can regulate the expression of mRNA and is involved in the development of autoimmune diseases, but few genetic studies are available. In this study we aimed to explore the lncRNA and mRNA changes of LEMS.

METHODS

Plasma lncRNA and mRNA expression profiles of three LEMS patients with small cell lung cancer (SCLC) and three matched healthy controls were analyzed by microarray. Differentially expressed lncRNAs and adjacent mRNAs were jointly analyzed, and candidates were verified by quantitative real-time polymerase chain reaction (qRT-PCR). The identified genes were subsequently evaluated in 9, 8, and 4 patients with paraneoplastic LEMS, nontumor LEMS, and SCLC, respectively. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to determine possible functions.

RESULTS

A total of 320 lncRNA and 168 mRNAs were differentially expressed in the three LEMS with SCLC and compared with healthy controls. Among these, lncRNA LOC338963 and its neighboring mRNA AP3B2 were upregulated jointly, which was confirmed by qRT-PCR. qRT-PCR revealed significant upregulation of the two genes in patients with paraneoplastic LEMS compared with nontumor LEMS or SCLC. GO analysis of AP3B2 identified the enrichment terms anterograde synaptic vesicle transport and establishment of synaptic vesicle localization. KEEG analysis showed that AP3B2 was enriched in lysosomal pathways.

DISCUSSION

LOC338963 and AP3B2 were upregulated in patients with paraneoplastic LEMS, suggesting their involvement in pathogenesis. These genes could be targets for exploring the pathomechanism of paraneoplastic LEMS.

Linear and Circular Long Non-Coding RNAs in Acute Lymphoblastic Leukemia: From Pathogenesis to Classification and Treatment

The coding regions account for only a small part of the human genome, and the remaining vast majority of the regions generate large amounts of non-coding RNAs. Although non-coding RNAs do not code for any protein, they are suggested to work as either tumor suppressers or oncogenes through modulating the expression of genes and functions of proteins at transcriptional, posttranscriptional and post-translational levels. Acute Lymphoblastic Leukemia (ALL) originates from malignant transformed B/T-precursor-stage lymphoid progenitors in the bone marrow (BM). The pathogenesis of ALL is closely associated with aberrant genetic alterations that block lymphoid differentiation and drive abnormal cell proliferation as well as survival. While treatment of pediatric ALL represents a major success story in chemotherapy-based elimination of a malignancy, adult ALL remains a devastating disease with relatively poor prognosis. Thus, novel aspects in the pathogenesis and progression of ALL, especially in the adult population, need to be further explored. Accumulating evidence indicated that genetic changes alone are rarely sufficient for development of ALL. Recent advances in cytogenic and sequencing technologies revealed epigenetic alterations including that of non-coding RNAs as cooperating events in ALL etiology and progression. While the role of micro RNAs in ALL has been extensively reviewed, less attention, relatively, has been paid to other non-coding RNAs. Herein, we review the involvement of linear and circular long non-coding RNAs in the etiology, maintenance, and progression of ALL, highlighting the contribution of these non-coding RNAs in ALL classification and diagnosis, risk stratification as well as treatment.

Comprehensive Analysis of Potential Biomarkers of Acute Lymphoblastic Leukemia in Children by Using a Competing Endogenous RNA Network

Acute lymphoblastic leukemia (ALL) is the most serious hematological carcinoma in adolescents. The significance of long noncoding RNAs (lncRNAs) and their regulative role in the proliferation and differentiation of myeloid cells in cancer has been recently reported. Nevertheless, key RNAs and the regulatory mechanism of competitive endogenous RNA (ceRNA) network affected by pediatric ALL are not fully illustrated. In this study, phase 2 and 3 pediatric ALL RNA profiles were extracted from the TARGET database and used to identify lncRNAs, microRNAs, and messenger RNAs in high-risk ALL and reconstruct the sponge ceRNA regulatory network. Results indicated that 44 lncRNAs, 25 miRNAs, and 115 mRNA were up/downregulated. Functional analysis with differentially expressed RNAs (DERNAs) showed enriched significant signaling pathways, including PI3K-Akt and p53 signaling cascades and other pathways associated with the tumor. Seventeen differential hub RNAs, including LINC00909, BZRAP1-AS1, C17orf76-AS1, HCG11, MIAT, SNHG5, SNHG15, and TP73-AS1, were identified. The Cox model of correlation indicated that 14 of these RNAs were associated with the progression of pediatric ALL. These findings would help clarify the regulatory role of several lncRNAs as well as provide insights into the leukemogenesis of pediatric ALL to further explore novel prognostic markers/therapeutic targets for ALL.

Non-coding RNAs: are they the protagonist or antagonist in the regulation of leukemia?

The idea of functional non-coding RNAs is taking precedence over the previous notion which believed that they only comprise the auxiliary and junk material of the genome. Newer technologies and studies have proven their importance in regulating and affecting several cellular processes. One such area of research wherein their importance has started to take light is in cancer research, particularly leukemia. Myeloid leukemia is a blood malignancy birthed from mutations in hematopoiesis that disable myeloid progenitor cells from proper differentiation. This review will compile the most recent findings regarding the effects of these regulatory non-coding RNAs on the two types of myeloid leukemia. In particular, the effects of circular RNAs, micro RNAs and long non-coding RNAs, on the pathogenesis and proliferation of Acute and Chronic myeloid leukemia will be revealed in a molecular, cellular and prognostic light. The mechanisms of proliferation, gene-to-gene interactions and possible therapeutic effects will also be discussed. Finally, an understanding of the overall "goodness" and "badness" of these non-coding RNAs will be summarised. This review hopes to provide a platform for easy access to data regarding the current non-coding RNAs in myeloid leukemia, for faster and easier research. Finally, the review will summarize a few key players that have protagonistic and antagonistic functions, and those that regulate multiple pathways in leukemia simultaneously.

Diverse functions of long noncoding RNAs in acute myeloid leukemia: emerging roles in pathophysiology, prognosis, and treatment resistance

PURPOSE OF REVIEW

Advancements in the next-generation sequencing technologies have identified rare transcripts of long noncoding RNAs (lncRNAs) in the genome of cancers, including in acute myeloid leukemia (AML). The purpose of this review is to highlight the contribution of lncRNAs in AML pathogenesis, prognosis, and chemoresistance.

RECENT FINDINGS

Several studies have recently reported that deregulated lncRNAs are novel key players in the development of AML and are associated with AML pathophysiology and may serve as prognostic indicators. A few aberrantly expressed lncRNAs that correlated with the recurrent genetic mutations in AML such as NPM1 and RUNX1 have recently been characterized. Moreover, a few lncRNAs in MLL-rearranged leukemia have been described. Additionally, the involvement of lncRNAs in AML chemoresistance has been postulated.

SUMMARY

Investigating the functional roles of the noncoding regions including lncRNAs, may provide novel insights into the pathophysiology, refine the prognostic schema, and provide novel therapeutic treatment strategies in AML.

HOTAIR expression and prognostic impact in acute myeloid leukemia patients

Background

Acute myeloid leukemia (AML) is a disorder characterized by a rapid onset of symptoms attributable to bone marrow failure due to clonal proliferation of primitive hematopoietic stem cells or progenitor cells. Epigenetic abnormalities play an important role in the development and progression of acute leukemia. Long non-coding ribonucleic acid (lncRNA) plays an important role in epigenetic regulation. Homeobox (Hox) transcript antisense intergenic RNA (HOTAIR) is a lncRNA which has been determined to be a negative prognostic indicator in various solid-tumor patients. However, its role in hematopoietic tumors as AML is to be assessed. This study aimed at measuring lncRNA HOTAIR expression level on bone marrow (BM) mononuclear cells in newly diagnosed AML patients and correlating its expression with their outcome and different prognostic variables. This provides new prospective for a novel marker involved in development and progression of AML which can be used as a diagnostic marker and a target of therapy. The current study included 65 subjects divided into 35 newly diagnosed AML adult patients (before initiation of chemotherapy) and 30 non-leukemic adult patients who are candidates for BM aspiration for causes other than hematological malignancies as immune thrombocytopenic purpura and hypersplenism as controls. HOTAIR expression was measured on BM mononuclear cells by quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Results

HOTAIR expression was found to be significantly upregulated in AML patients (probability (p) value = 0.000) and it can be used as a diagnostic biomarker of AML as confirmed by a significant difference between cases and controls using receiver operating characteristic curve (ROC) analysis. However, it was not significantly correlated with event free survival (EFS) or prognostic variables.

Conclusion

This study showed that the expression of HOTAIR is upregulated in de novo AML patients and can be used as a diagnostic marker. However, highly expressed HOTAIR is not associated with poor prognosis.

HOTAIR suppresses PTEN via DNMT3b and confers drug resistance in acute myeloid leukemia

OBJECTIVE

HOTAIR has been well reported to be involved in the drug resistance of many diseases. This study aims to explore the possible implication of HOTAIR in doxorubicin (ADM) resistance in acute myeloid leukemia (AML).

METHODS

Expressions of HOTAIR and PTEN in bone marrows of patient with newly diagnosed AML and relapsed/refractory AML and of healthy controls were determined by RT-qPCR. The half maximal inhibitory concentration (IC50) was calculated after AML-ADM-sensitive cells HL60 and AML-ADM-resistant cells HL60/ADM cells were treated by ADM. The IC50 of HL60/ADM to ADM dosage was determined by CCK-8. After cells were transfected with Sh-HOTAIR, pcDNA3.1-HOTAIR or pcDNA3.1-PTEN, cell biology of HL60/ADM cells was detected by flow cytometry, clone formation assay. The methylation of PTEN was determined by Methylmion-specific PCR and Bisulfite Genomic Sequence.

RESULTS

Patient with relapsed/refractory AML had the highest HOTAIR and the lowest PTEN expression, followed by that in newly diagnosed AML patients and then healthy controls. After ADM treatment, cell viability and IC50 were enhanced in HL60/ADM cell when compared with HL60 cells. Up-regulated HOTAIR and down-regulated PTEN were found in HL60/ADM cells. Cell transfection with sh-HOTAIR or pcDNA3.1-PTEN leads to increased ADM sensitivity, apoptosis rate as well as decreased IC50 and cell clones, while those expression patterns can be reversed by co-transfection of pcDNA3.1-PTEN and pcDNA3.1-HOTAIR. Methylation was observed in the promoter of PTEN. HOTAIR can positively regulate DNMT3b.

CONCLUSION

HOTAIR suppresses PTEN through up-regulating DNMT3b-dependent way and confers ADM resistance in AML.

Association between CYP2B6 c.516G >T variant and acute leukaemia: A protocol for systematic review and meta-analysis

BACKGROUND

Acute leukemia (AL) is a kind of malignant tumor of hematopoietic system. A number of studies have suggested that Single Nucleotide Polymorphisms are significantly associated with risk of AL. Present study performs meta-analysis to evaluate the association between CYP2B6 c.516G>T variant and AL risk.

METHODS

Databases including PubMed, EMBASE, Chinese National Knowledge Infrastructure (CNKI), and Wanfang were searched for literatures to September 30, 2019, both in English and Chinese. Relative risk and its 95% confidence intervals were used to assess the associations. Statistical analyses of this meta-analysis were conducted by using STATA 13.0. software.

RESULTS

A total of 7 studies, including 1038 cases and 1648 controls, were analyzed. Our results indicated that CYP2B6 c.516G>T variant was significantly related to an increased the risk of AL under dominant model, recessive model, homozygote model, and allelic model. In addition, subgroup analyses were also performed by disease classification, country, and study design. No significant associations were obtained between CYP2B6 c.516G>T variant and the risk of AL under the recessive model in the design of hospital-based (relative risk = 0.98; 95% confidence interval: 0.95-1.01; P  = 0.118).

CONCLUSION

Our meta-analysis indicated that the CYP2B6 variant is significantly associated with AL risk, in which CYP2B6 c.516G>T is related to an increased risk of AL.

An immunotherapeutic approach to decipher the role of long non-coding RNAs in cancer progression, resistance and epigenetic regulation of immune cells

Immunotherapeutic treatments are gaining attention due to their effective anti-tumor response. Particularly, the revolution of immune checkpoint inhibitors (ICIs) produces promising outcomes for various cancer types. However, the usage of immunotherapy is limited due to its low response rate, suggesting that tumor cells escape the immune surveillance. Rapid advances in transcriptomic profiling have led to recognize immune-related long non-coding RNAs (LncRNAs), as regulators of immune cell-specific gene expression that mediates immune stimulatory as well as suppression of immune response, indicating LncRNAs as targets to improve the efficacy of immunotherapy against tumours. Moreover, the immune-related LncRNAs acting as epigenetic modifiers are also under deep investigation. Thus, herein, is a summarised knowledge of LncRNAs and their regulation in the adaptive and innate immune system, considering their importance in autophagy and predicting putative immunotherapeutic responses.

Identification of Potential Signatures and Their Functions for Acute Lymphoblastic Leukemia: A Study Based on the Cancer Genome Atlas

Objective

Acute lymphoblastic leukemia (ALL) is a malignant disease most commonly diagnosed in adolescents and young adults. This study aimed to explore potential signatures and their functions for ALL.

Methods

Differentially expressed mRNAs (DEmRNAs) and differentially expressed long non-coding RNAs (DElncRNAs) were identified for ALL from The Cancer Genome Atlas (TCGA) and normal control from Genotype-Tissue Expression (GTEx). DElncRNA-microRNA (miRNA) and miRNA-DEmRNA pairs were predicted using online databases. Then, a competing endogenous RNA (ceRNA) network was constructed. Functional enrichment analysis of DEmRNAs in the ceRNA network was performed. Protein-protein interaction (PPI) network was then constructed. Hub genes were identified. DElncRNAs in the ceRNA network were validated using Real-time qPCR.

Results

A total of 2,903 up- and 3,228 downregulated mRNAs and 469 up- and 286 downregulated lncRNAs were identified for ALL. A ceRNA network was constructed for ALL, consisting of 845 lncRNA-miRNA and 395 miRNA-mRNA pairs. These DEmRNAs in the ceRNA network were mainly enriched in ALL-related biological processes and pathways. Ten hub genes were identified, including SMAD3, SMAD7, SMAD5, ZFYVE9, FKBP1A, FZD6, FZD7, LRP6, WNT1, and SFRP1. According to Real-time qPCR, eight lncRNAs including ATP11A-AS1, ITPK1-AS1, ANO1-AS2, CRNDE, MALAT1, CACNA1C-IT3, PWRN1, and WT1-AS were significantly upregulated in ALL bone marrow samples compared to normal samples.

Conclusion

Our results showed the lncRNA expression profiles and constructed ceRNA network in ALL. Furthermore, eight lncRNAs including ATP11A-AS1, ITPK1-AS1, ANO1-AS2, CRNDE, MALAT1, CACNA1C-IT3, PWRN1, and WT1-AS were identified. These results could provide a novel insight into the study of ALL.

Abnormal expression and methylation of PRR34-AS1 are associated with adverse outcomes in acute myeloid leukemia

It was previously reported that PRR34‐AS1 was overexpressed in some solid tumors. PRR34‐AS1 promoter was shown to have a differential methylation region (DMR), and was hypomethylated in acute myeloid leukemia (AML). Therefore, the present study used real‐time quantitative PCR (RQ‐PCR) to explore the expression characteristics of PRR34‐AS1 in AML. In addition, the correlation between the expression of PRR34‐AS1 and clinical prognosis of AML was determined. The findings of this study indicated that high PRR34‐AS1 expression was bound up with shorter overall survival (OS) in AML patients (p = 0.002). Moreover, patients with high expression of PRR34‐AS1 had significantly lower complete remission (CR) rate compared with those with low expression of PRR34‐AS1 after induction chemotherapy. Furthermore, multivariate analysis confirmed that PRR34‐AS1 expression was an independent factor affecting CR in whole‐AML, non‐APL‐AML, and CN‐AML patients (p = 0.032, 0.039, and 0.036, respectively). Methylation‐specific PCR (MSP) and bisulfite sequencing PCR (BSP) were used to explore the methylation status of PRR34‐AS1. PRR34‐AS1 promoter showed a pattern of hypomethylation in AML patients compared with normal controls (p = 0.122). Notably, of whole‐AML and non‐APL‐AML patients, PRR34‐AS1 hypomethylated patients presented a significantly shorter OS than those with a hypermethylated PRR34‐AS1 (p = 0.010 and 0.037, respectively). Multivariate analysis confirmed that the hypomethylation of PRR34‐AS1 served as an independent prognostic indicator in both whole‐cohort AML and non‐APL‐AML categories (p = 0.057 and 0.018, respectively). In summary, the findings of this study showed that abnormalities in PRR34‐AS1 are associated with poor prognosis in AML. Therefore, monitoring this index may be important in the prognosis of AML and can provide information on effective chemotherapy against the disease.

Study of HOTAIR LncRNA in AML patients in context to FLT3-ITD and NPM1 mutations status

Background

Long non-coding RNAs (LncRNAs) have recently been considered promising biomarkers for oncogenesis due to their epigenetic regulatory effects. HOTAIR is one of the oncogenic LncRNAs that was previously studied in different non-hematological malignancies. The current study set out to detect the expression level of HOTAIR LncRNA in AML patients concerning their clinical characteristics, laboratory data, FLT3-ITD, and NPM1 mutations, as well as treatment outcome. This study included quantitative detection of HOTAIR gene expression in 47 cases of AML using quantitative reverse transcription polymerase chain reaction, as well as NPM1 and FLT3-ITD genotyping.

Results

The HOTAIR expression was significantly higher in AML patients 6.87 (0.001) than in normal controls 1.66 (0.004–6.82) (p 0.007). The HOTAIR expression level was affected by chemotherapy, and it was correlated to hemoglobin level (p 0.001), age, total leukocytic count (p 0.022), and NPM1 mutation (p 0.017). HOTAIR gene expression level showed a correlation to relapse-free survival in the study group (p 0.04).

Conclusion

HOTAIR is overexpressed in patients with acute myeloid leukemia (AML). HOTAIR pre-treatment and post-chemotherapy gene expression levels can predict chemosensitivity and relapse.

The prognostic impact of abnormally expressed, long noncoding RNAs in acute myeloid leukemia: a meta-analysis

Objectives: A growing number of studies demonstrate that long noncoding RNAs (lncRNAs) could act as biomarkers to determine the prognosis of acute myeloid leukemia (AML) patients. Nonetheless, the significance of lncRNAs in AML prognosis remains unclear. We conducted a meta-analysis to assess the prognostic indicators of abnormally expressed lncRNAs in AML. Methods: Literature was searched using PubMed, EMBASE, and Web of Science databases up to November 10, 2018. Results: Thirteen studies with 2755 individuals were included. The abnormal expression of lncRNAs was associated with worse overall survival (OS) in AML patients, especially in cytogenetically normal AML (CN-AML), and was associated with shorter disease-free survival and event-free survival. Subgroup analysis showed that high levels of HOTAIR and TUG1 were associated with poor OS. Discussion: Overexpression of lncRNA HOTAIR and TUG1 were reported in two separate studies, and correlated with worse AML prognoses. Conclusion: Abnormally expressed lncRNAs are significantly related to worse prognoses of AML patients and might serve as potential prognostic markers to predict the prognosis of AML patients.

Post-menopausal oestrogen deficiency induces osteoblast apoptosis via regulating HOTAIR/miRNA-138 signalling and suppressing TIMP1 expression

In this study, we aimed to explore the molecular mechanisms underlying the development of osteoporosis in post‐menopausal females. Real‐time PCR was conducted to measure the expression of potential lncRNAs involved in the osteoporosis of post‐menopausal females. In addition, Western blot and IHC assays were used to study the possible correlation among HOTAIR, miR‐138 and TIMP1, while a computational analysis was carried out to predict the ‘seed sequence’ responsible for the binding between miR‐138 and HOTAIR/TIMP1. Furthermore, luciferase reporter assays were conducted to validate the negative regulatory relationship between miR‐138 and TIMP1/HOTAIR. To evaluate the effect of oestrogen on the function of HOATIR and its downstream effectors, luciferase activity was measured in cells cotransfected with different vectors or treated with different doses of oestrogen. The results of the luciferase assay were further validated by real‐time PCR, Western blot, MTT assay and flow cytometry. Among the candidate lncRNAs, HOTAIR was the only lncRNA down‐regulated in post‐menopausal females. HOTAIR bound to miR‐138 and negatively regulated its expression. Meanwhile, miR‐138 could also bind to TIMP1 mRNA and reduce its expression. Furthermore, a dose‐dependent up‐regulation of HOTAIR was observed in cells treated with oestrogen, and the elevated HOTAIR increased the level of TIMP1 by targeting miR‐138. In addition, oestrogen promoted cell viability and suppressed cell apoptosis, and effects of oestrogen were blocked by the silencing of HOTAIR. Therefore, it can be concluded that oestrogen deficiency could induce the apoptosis of osteoblasts and lead to osteoporosis in post‐menopausal females via modulation of the HOTAIR/miR‐138/TIMP1 signalling axis.

Long non-coding RNA HOTAIR regulates myeloid differentiation through the upregulation of p21 via miR-17-5p in acute myeloid leukaemia

Long non-coding RNA HOTAIR has been reported to play a key role in regulating various biological processes in various cancers. However, the roles and mechanisms of HOTAIR in acute myeloid leukaemia (AML) are still unclear and need to be investigated. In this study, we induced differentiation of four AML cell lines by all-trans retinoic acid (ATRA) and found HOTAIR was significantly upregulated in the process. Chromatin immunoprecipitation (ChIP) assays indicated that C/EBPβ upregulated HOTAIR during ATRA induced differentiation in HL-60 cells. By gain- and loss-of-function analysis, we then observed that HOTAIR expression was positively correlated with ATRA-induced differentiation and negatively regulated G1 phase arrest in HL-60 cells. In addition, we found that HOTAIR promoted ATRA-induced differentiation via the regulation of the cell cycle regulator p21 via miR-17-5p. Moreover, we detected the expression of HOTAIR in 84 de novo AML patients, HOTAIR was found significantly downregulated in the AML patients compared to the iron deficiency anaemia (IDA) control group, negatively correlated with the platelet level in M2 patients. In all, our data suggest that HOTAIR may be subtype-specific in AML-M2 patients, also HOTAIR regulates AML differentiation by C/EBPBβ/HOTAIR/miR-17-5p/p21 pathway. The findings of the present study provide a novel insight into the mechanism of lncRNA-mediated differentiation and indicate that HOTAIR may be a promising therapeutic target for leukaemia, especially for AML with M2 type.Abbreviation: AML: acute myeloid leukaemia; APL: acute promyelocytic leukaemia; ATRA: all-trans retinoic acid; CCK8: cell Counting Kit-8; CDKs: cyclin-dependent kinases ; CeRNA: competing endogenous RNAs; ChIP: chromatin immunoprecipitation; CHX: cycloheximide; FAB: French-American-British; FCM: flow cytometry; HOTAIR: HOX transcript antisense RNA; IDA: iron-deficiency anemia; lncRNA: long non-coding RNA; 3'UTR: 3'untranslated region; MT: Mutation type; WT: Wild type; qRT-PCR: Quantitative real-time PCR.

LINC00649 underexpression is an adverse prognostic marker in acute myeloid leukemia

BACKGROUND

Long noncoding RNAs (lncRNA) play a role in leukemogenesis, maintenance, development, and therapeutic resistance of AML. While few studies have focused on the prognostic significance of LINC00649 in AML, which we aim to investigate in this present study.

METHODS

We compared the expression level of LINC00649 between AML patients and healthy controls. The Kaplan-Meier curves of AML patients expressing high versus low level of LINC00649 was performed. The LINC00649 correlated genes/miRNAs/lncRNAs and methylation CpG sites were screened by Pearson correlation analysis with R (version 3.6.0), using TCGA-LAML database. The LINC00649 associated ceRNA network was established using lncBase 2.0 and miRWalk 2.0 online tools, combining results from correlation analysis. Finally, a prediction model was constructed using LASSO-Cox regression.

RESULTS

LINC00649 was underexpressed in bone marrow of AML group than that in healthy control group. The patients of LINC00649-low group have significantly inferior PFS and OS. A total of 154 mRNAs, 31 miRNAs, 28 lncRNAs and 1590 methylated CpG sites were identified to be significantly correlated with LINC00649. Furthermore, the network of ceRNA was established with 6 miRNAs and 122 mRNAs. The Lasso-Cox model fitted OS/PFS to novel prediction models, which integrated clinical factors, ELN risk stratification, mRNA/miRNA expression and methylation profiles. The analysis of time-dependent ROC for our model showed a superior AUC (AUC = 0.916 at 1 year, AUC = 0.916 at 3 years, and AUC = 0.891 at 5 years).

CONCLUSIONS

Low expression of LINC00649 is a potential unfavorable prognostic marker for AML patients, which requires the further validation. The analysis by LASSO-COX regression identified a novel comprehensive model with a superior diagnostic utility, which integrated clinical and genetic variables.

lncRNAs-mRNAs Co-Expression Network Underlying Childhood B-Cell Acute Lymphoblastic Leukaemia: A Pilot Study

Simple Summary

Acute lymphoblastic leukemia (ALL) is one of the most common childhood cancers. The ALL onset involves abnormal proliferation and arrest of differentiation of B or T cell progenitors. Recently, long non–coding RNAs (lncRNAs) gained great interest in the B–ALL leukemogenesis, however, so far few “omic” studies investigate lncRNAs and protein–coding gene networks. In our retrospective study, we conceived an integrated bioinformatic approach, by using NGS platform, to discover lncRNAs strongly correlated with aberrantly expressed protein–coding genes. We provided dysregulated lncRNA–mRNA pairs potentially underlying B–ALL pathogenesis. Diagnosis incidence peak of ALL appears approximatively between 1 and 19 years old. lncRNAs may be of clinical utility as non–invasive biomarker for B–ALL onset or therapy response in support of precision medicine. The identification of lncRNA as key regulators in B–ALL could lead to the identification of the altered pathways able to sustain the leukemic growth.

Abstract

Long non–coding RNAs (lncRNAs) are emerging as key gene regulators in the pathogenesis and development of various cancers including B lymphoblastic leukaemia (B–ALL). In this pilot study, we used RNA–Seq transcriptomic data for identifying novel lncRNA–mRNA cooperative pairs involved in childhood B–ALL pathogenesis. We conceived a bioinformatic pipeline based on unsupervised PCA feature extraction approach and stringent statistical criteria to extract potential childhood B–ALL lncRNA signatures. We then constructed a co–expression network of the aberrantly expressed lncRNAs (30) and protein–coding genes (754). We cross–validated our in–silico findings on an independent dataset and assessed the expression levels of the most differentially expressed lncRNAs and their co–expressed mRNAs through ex vivo experiments. Using the guilt–by–association approach, we predicted lncRNA functions based on their perfectly co–expressed mRNAs (Spearman’s correlation) that resulted closely disease–associated. We shed light on 24 key lncRNAs and their co–expressed mRNAs which may play an important role in B–ALL pathogenesis. Our results may be of clinical utility for diagnostic and/or prognostic purposes in paediatric B–ALL management.

Aberrant LncRNA Expression in Leukemia

Leukemia is a common malignant cancer of the hematopoietic system, whose pathogenesis has not been fully elucidated. Long noncoding RNAs (lncRNAs) are transcripts longer than 200 nucleotides without protein-coding function. Recent studies report their role in cellular processes such as the regulation of gene expression, as well as in the carcinogenesis, occurrence, development, and prognosis of various tumors. Evidence indicating relationships between a variety of lncRNAs and leukemia pathophysiology has increased dramatically in the previous decade, with specific lncRNAs expected to serve as diagnostic biomarkers, novel therapeutic targets, and predictors of clinical outcomes. Furthermore, these lncRNAs might offer insight into disease pathogenesis and novel treatment options. This review summarizes progress in studies on the role(s) of lncRNAs in leukemia.

Epigenetic landscape analysis of lncRNAs in acute myeloid leukemia with DNMT3A mutations

Background

Acute myeloid leukemia (AML) is a type of cancer that consists of a group of hematological malignancies with high heterogeneity. DNA methyltransferase 3A (DNMT3A)-mutated AML patients have a poor prognosis. Some long non-coding RNAs (lncRNAs) have been reported to enhance therapeutic sensitivity, and so could affect the overall survival rate of elderly cytogenetically normal acute myeloid leukemia (CN-AML) patients; however, studies on the lncRNA signature in DNMT3A-mutated AML are rare.

Method

The DNMT3A R878H conditional knock-in mouse model was constructed to explore the lncRNAs of DNMT3A mutation by using the Cuffcomparison method. Cis and trans regulation networks were used to predict candidate genes. The expression levels in leukemic cell lines and the prognostic index of these candidate genes were analyzed with the Broad Institute Cancer Cell Line Encyclopedia (CCLE) and OncoLnc databases. The data for each sample were statistically analyzed using GraphPad Prism.

Results

In this study, we applied the DNMT3A R878H conditional knock-in mouse model to explore the lncRNA epigenetic landscape of DNMT3A mutation by using the Cuffcomparison method. Twenty-three differentially expressed lncRNAs were identified in Dnmt3a^R878H/WTMx1-Cre⁺ mice. We next predicted the downstream targetable genes regulated by these lncRNAs through cis and trans regulation networks and found 124 candidate genes are related to these lncRNAs. In further analysis of 124 genes, we found that increased mRNA expression levels of interleukin 1 receptor type 2 (IL1R2), Krüppel-like factor 13 (KLF13), ATPase H+ transporting V1 subunit A (ATP6V1A), proteasome 26S Subunit, non-ATPase 3 (PSMD3), and pyrroline-5-carboxylate reductase 2 (PYCR2) were associated with poor prognosis in AML. Functional analysis of these genes demonstrated that the pathways involved in autophagy, cell cycle, and hematopoietic stem cell differentiation were more enriched in Dnmt3a^R878H/WTMx1-Cre⁺ mice.

Conclusion

Our study was the first to use DNMT3A R878H conditional knock-in mouse model to predict the specific lncRNAs regulated by the DNMT3A mutation in AML. Six candidate genes were found to be associated with DNMT3A mutation with poor prognosis. Our results provided a possible treatment strategy for this disease.

Methyltransferase DNMT3B in leukemia

DNA methyltransferases (DNMTs) are highly conserved DNA-modifying enzymes that play important roles in epigenetic regulation and they are involved in cell proliferation, differentiation, and apoptosis. In mammalian cells, three active DNMTs have been identified: DNMT1 acts as a maintenance methyltransferase to replicate preexisting methylation patterns, whereas DNMT3A and DNMT3B primarily act as de novo methyltransferases that are responsible for establishing DNA methylation patterns by adding a methyl group to cytosine bases. The expression of DNMT3B is widespread in a variety of hematological cells and it is altered in each type of leukemia, which is associated with its pathogenesis, progression, treatment, and prognosis. Here, we review current information on DNMT3B in leukemia, including its expression, single-nucleotide polymorphisms, mutations, regulation, function, and clinical value for anti-leukemic therapy and prognosis.

Long Noncoding RNAs in Acute Myeloid Leukemia: Functional Characterization and Clinical Relevance

Acute Myeloid Leukemia (AML) is the most common form of leukemia in adults with an incidence of 4.3 per 100,000 cases per year. Historically, the identification of genetic alterations in AML focused on protein-coding genes to provide biomarkers and to understand the molecular complexity of AML. Despite these findings and because of the heterogeneity of this disease, questions as to the molecular mechanisms underlying AML development and progression remained unsolved. Recently, transcriptome-wide profiling approaches have uncovered a large family of long noncoding RNAs (lncRNAs). Larger than 200 nucleotides and with no apparent protein coding potential, lncRNAs could unveil a new set of players in AML development. Originally considered as dark matter, lncRNAs have critical roles to play in the different steps of gene expression and thus affect cellular homeostasis including proliferation, survival, differentiation, migration or genomic stability. Consequently, lncRNAs are found to be differentially expressed in tumors, notably in AML, and linked to the transformation of healthy cells into leukemic cells. In this review, we aim to summarize the knowledge concerning lncRNAs functions and implications in AML, with a particular emphasis on their prognostic and therapeutic potential.

Long Non-Coding RNA in the Pathogenesis of Cancers

The incidence and mortality rate of cancer has been quickly increasing in the past decades. At present, cancer has become the leading cause of death worldwide. Most of the cancers cannot be effectively diagnosed at the early stage. Although there are multiple therapeutic treatments, including surgery, radiotherapy, chemotherapy, and targeted drugs, their effectiveness is still limited. The overall survival rate of malignant cancers is still low. It is necessary to further study the mechanisms for malignant cancers, and explore new biomarkers and targets that are more sensitive and effective for early diagnosis, treatment, and prognosis of cancers than traditional biomarkers and methods. Long non-coding RNAs (lncRNAs) are a class of RNA transcripts with a length greater than 200 nucleotides. Generally, lncRNAs are not capable of encoding proteins or peptides. LncRNAs exert diverse biological functions by regulating gene expressions and functions at transcriptional, translational, and post-translational levels. In the past decade, it has been demonstrated that the dysregulated lncRNA profile is widely involved in the pathogenesis of many diseases, including cancer, metabolic disorders, and cardiovascular diseases. In particular, lncRNAs have been revealed to play an important role in tumor growth and metastasis. Many lncRNAs have been shown to be potential biomarkers and targets for the diagnosis and treatment of cancers. This review aims to briefly discuss the latest findings regarding the roles and mechanisms of some important lncRNAs in the pathogenesis of certain malignant cancers, including lung, breast, liver, and colorectal cancers, as well as hematological malignancies and neuroblastoma.

lncRNA SNHG3 facilitates acute myeloid leukemia cell growth via the regulation of miR-758-3p/SRGN axis

Small nucleolar RNA host gene 3 (SNHG3) is a newly identified long non-coding RNA whose dysregulation has been reported in several cancers. However, the details about clinical significances and biological functions of SNHG3 on acute myeloid leukemia (AML) remain covered. In this study, we revealed increased SNHG3 expression in AML samples and cells and its high potential as a prognostic biomarker for AML patients. Likewise, serglycin (SRGN), which plays an important role in granule-mediated apoptosis, was previously verified to be upregulated in AML and confirmed again by the present study, and its upregulation predicted poor outcomes in AML. Furthermore, knockdown of SNHG3 or SRGN inhibited cell proliferation and induced cell apoptosis. Besides, silencing SNHG3 noticeably decreased the expression of SRGN in AML cells. Moreover, we uncovered that SNHG3 modulated SRGN expression by competitively binding with miR-758-3p. Importantly, both miR-758-3p suppression and SRGN overexpression could mitigate the inhibitory effects of SNHG3 depletion on AML cell growth. Intriguingly, the higher SRGN expression in AML samples with a higher SNHG3 level exhibited an enhanced Ki67 level but a reduced caspase 3 level. To sum up, SNHG3 elicits a growth-promoting function in AML via sponging miR-758-3p to regulate SRGN expression, providing a new therapeutic road for AML patients.

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.

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.

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.

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.

The Epigenome in Multiple Myeloma: Impact on Tumor Cell Plasticity and Drug Response

Multiple myeloma (MM) is a clonal plasma cell malignancy that develops primarily in the bone marrow (BM), where reciprocal interactions with the BM niche foster MM cell survival, growth, and drug resistance. MM cells furthermore reshape the BM to their own needs by affecting the different BM stromal cell types resulting in angiogenesis, bone destruction, and immune suppression. Despite recent advances in treatment modalities, MM remains most often incurable due to the development of drug resistance to all standard of care agents. This underscores the unmet need for these heavily treated relapsed/refractory patients. Disruptions in epigenetic regulation are a well-known hallmark of cancer cells, contributing to both cancer onset and progression. In MM, sequencing and gene expression profiling studies have also identified numerous epigenetic defects, including locus-specific DNA hypermethylation of cancer-related and B cell specific genes, genome-wide DNA hypomethylation and genetic defects, copy number variations and/or abnormal expression patterns of various chromatin modifying enzymes. Importantly, these so-called epimutations contribute to genomic instability, disease progression, and a worse outcome. Moreover, the frequency of mutations observed in genes encoding for histone methyltransferases and DNA methylation modifiers increases following treatment, indicating a role in the emergence of drug resistance. In support of this, accumulating evidence also suggest a role for the epigenetic machinery in MM cell plasticity, driving the differentiation of the malignant cells to a less mature and drug resistant state. This review discusses the current state of knowledge on the role of epigenetics in MM, with a focus on deregulated histone methylation modifiers and the impact on MM cell plasticity and drug resistance. We also provide insight into the potential of epigenetic modulating agents to enhance clinical drug responses and avoid disease relapse.

Disordered Regions of Mixed Lineage Leukemia 4 (MLL4) Protein Are Capable of RNA Binding

Long non-coding RNAs (lncRNAs) are emerging as important regulators of cellular processes and are extensively involved in the development of different cancers; including leukemias. As one of the accepted methods of lncRNA function is affecting chromatin structure; lncRNA binding has been shown for different chromatin modifiers. Histone lysine methyltransferases (HKMTs) are also subject of lncRNA regulation as demonstrated for example in the case of Polycomb Repressive Complex 2 (PRC2). Mixed Lineage Leukemia (MLL) proteins that catalyze the methylation of H3K4 have been implicated in several different cancers; yet many details of their regulation and targeting remain elusive. In this work we explored the RNA binding capability of two; so far uncharacterized regions of MLL4; with the aim of shedding light to the existence of possible regulatory lncRNA interactions of the protein. We demonstrated that both regions; one that contains a predicted RNA binding sequence and one that does not; are capable of binding to different RNA constructs in vitro. To our knowledge, these findings are the first to indicate that an MLL protein itself is capable of lncRNA binding.

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.

Association between the HOTAIR polymorphisms and cancer risk: an updated meta-analysis

Purpose

LncRNA HOTAIR plays an important role in many cancer. Several studies have shown that some HOTAIR SNPs might be associated with tumor risk in case-control studies, but the results are inconsistent and inconclusive. Therefore, it is necessary to better evaluate association between the HOTAIR SNPs and the risk of cancer.

Results

rs920778, rs7958904 and rs874945 but not rs4759314 and rs1899663 loci were significantly related to cancer risk, among of which rs920778 and rs874945 increased and rs7958904 decreased cancer risk, respectively. Moreover, rs920778 is significantly susceptible in both Asian population and digestive cancer risks.

Materials and Methods

Data were collected from PubMed, Embase and Web of Science. A total of 11 case-control studies were selected for the quantitative analysis. Software Stata (Version 12) was used to calculate Odds ratios (ORs) and 95% confidence intervals (CIs) to evaluate the strength of the associations. Subgroup analysis, sensitivity analysis, and publication bias were also performed. Five HOTAIR SNPs were finally enrolled in the study.

Conclusions

HOTAIR SNP rs920778, rs7958904 and rs874945 are susceptible to cancer risk. SNP rs920778 is also a useful risk factor in evaluation of Asian population and digestive cancer. In addition, the cancer risk SNP rs874945 is first reported in the meta-analysis.

The association between HOTAIR polymorphisms and cancer susceptibility: an updated systemic review and meta-analysis

OBJECTIVES

This work aims to explore whether HOX transcript antisense intergenic RNA (HOTAIR) polymorphisms are associated with cancer susceptibility.

MATERIALS AND METHODS

A comprehensive search was conducted for literature published from January 2007 to July 2017. The pooled odds ratios (ORs) and the corresponding 95% CIs were calculated using the Revman 5.2 software. Eighteen articles of 36 case-control studies were enrolled including six HOTAIR polymorphisms and 10 cancer types.

RESULTS

The results showed that cancer risk was elevated in recessive mutation of rs12826786 (TT vs CC+CT: OR =1.55, 95% CI =1.19, 2.03; TT+CT vs CC: OR =1.23, 95% CI =1.04, 1.46; TT vs CC: OR =1.67, 95% CI =1.24, 2.24; T vs C: OR =1.24, 95% CI =1.09, 1.40) and rs920778 (TT vs CC+CT: OR =1.73, 95% CI =1.30, 2.30; TT+CT vs CC: OR =1.40, 95% CI =1.16, 1.70; TT vs CC: OR =1.83, 95% CI =1.25, 2.68; T vs C: OR =1.37, 95% CI =1.18, 1.59), while the results for polymorphisms of rs7958904, rs4759314, rs874945, and rs1899663 were insignificant. The stratified results for Chinese population were consistent with the overall group analysis.

CONCLUSION

Our meta-analysis showed that HOTAIR polymorphisms of rs12826786 and rs920778 were correlated with increased cancer risk, while rs7958904, rs4759314, rs874945, and rs1899663 were not. More studies with different types of cancer are needed to confirm the findings.

Pretreatment platelet count predicts survival outcome of patients with de novo non-M3 acute myeloid leukemia

Background

Pretreatment platelet count has been reported as a potential tool to predict survival outcome in several solid tumors. However, the predictive value of pretreatment platelet count remains obscure in de novo acute myeloid leukemia (AML) excluding acute promyelocytic leukemia (M3).

Methods

We conducted a retrospective review of 209 patients with de novo non-M3 AML in our institute over a period of 8 years (2007–2015). Receiver operating characteristic (ROC) curve analysis was used to determine the optimal platelet (PLT) cutoff in patients. We analyzed the overall survival (OS) and disease free survival (DFS) using the log-rank test and Cox regression analysis.

Results

By defining the platelet count 50 × 10⁹/L and 120 × 10⁹/L as two cut-off points, we categorized the patients into three groups: low (<50 × 10⁹/L), medium (50–120 × 10⁹/L) and high (>120 × 10⁹/L). On univariate analysis, patients with medium platelet count had longer OS and DFS than those with low or high platelet count. However, the multivariate analysis showed that only longer DFS was observed in patients with medium platelet count than those with low or high platelet count.

Conclusion

Our findings indicate that pretreatment platelet count has a predictive value for the prognosis of patients with non-M3 AML.

LncRNA HOTAIR alleviates rheumatoid arthritis by targeting miR-138 and inactivating NF-κB pathway

Rheumatoid arthritis (RA) is a chronic and autoimmune-mediated inflammatory disease. We aimed to investigate the regulation of lncRNA HOTAIR in LPS-treated chondrocytes and RA mouse. Our results showed that HOTAIR expression was significantly reduced in LPS-treated chondrocytes. The HOTAIR was then over-expressed in chondrocytes by transfecting recombinant lentivirus carrying sequences encoding HOTAIR. The LPS-induced reduction of cell proliferation rate and production of two inflammatory factors interleukin (IL)-17, IL-23 were markedly inhibited. Enforced expression of HOTAIR also led to the upregulation of proliferation-related protein Ki67 and proliferating cell nuclear antigen (PCNA). Moreover, a negative correlation was detected between the expression of HOTAIR and microRNA (miR)-138, and the expression of miR-138 was significantly increased in LPS-induced chondrocytes. The effects of HOTAIR over-expression on the proliferation and inflammation were partly reversed by miR-138 overexpression. Furthermore, the overexpression of HOTAIR significantly inhibited the activation of nuclear transcription factor-κB (NF-κB) in LPS-treated chondrocytes by suppressing p65 to cell nucleus, resulting in the down-regulation of IL-1β and tumor necrosis factor (TNF)-α. In addition, the in vivo experiments exhibited that overexpression of HOTAIR increased cell proliferation and inhibited inflammation in RA rats, which were demonstrated by upregulation of Ki67 and PCNA, reduced CD4⁺IL-17⁺,CD4⁺IL-23⁺ cells, and down-regulation of p-p65, IL-1β and TNF-α. In summary, our study suggests HOTAIR plays a protective role in RA by increasing proliferation rate and inhibiting inflammation, which may be related with the regulation of miR-138 expression and NF-κB signaling pathway. These results suggest that the regulation of HOTAIR may be a promising therapeutic strategy for RA.

Upregulation of long non-coding RNA MALAT-1 confers poor prognosis and influences cell proliferation and apoptosis in acute monocytic leukemia

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1), a long non-coding RNA, has been documented to be a new prognostic marker and gene regulator in several types of cancer, but its potential involvement in acute myeloid leukemia (AML) remains unclear. This study investigated the expression and functional role of MALAT-1 in AML. MALAT-1 expression was assessed by real-time quantitative PCR. After lentiviral-mediated MALAT-1 knockdown, the proliferation of AML cells was determined by CCK-8 and colony formation assays. Cell cycle progression and apoptosis were evaluated by flow cytometry and the expression of caspase-3, −8 and −9 was assessed by western blot analysis. We found that MALAT-1 expression in patients with acute monocytic leukemia (M5) was significantly increased when compared with that of healthy controls, and the overall survival of M5 patients with high MALAT-1 expression was markedly reduced when compared with the overall survival of patients with low MALAT-1 expression. The analysis of cellular experiments showed that MALAT-1 silencing decreased the proliferation of M5 cells (U-937 and THP-1), inhibited cell cycle progression and increased apoptosis. Taken together, these findings suggest that high MALAT-1 expression is closely associated with poor prognosis in M5 patients and may play a role in leukemia cell proliferation and apoptosis, and may serve as a promising theranostic marker.