A childhood acute lymphoblastic leukemia-specific lncRNA implicated in prednisolone resistance, cell proliferation, and migration

Non-coding RNAs in leukemia drug resistance: new perspectives on molecular mechanisms and signaling pathways

Like almost all cancer types, timely diagnosis is needed for leukemias to be effectively cured. Drug efflux, attenuated drug uptake, altered drug metabolism, and epigenetic alterations are just several of the key mechanisms by which drug resistance develops. All of these mechanisms are orchestrated by up- and downregulators, in which non-coding RNAs (ncRNAs) do not encode specific proteins in most cases; albeit, some of them have been found to exhibit the potential for protein-coding. Notwithstanding, ncRNAs are chiefly known for their contribution to the regulation of physiological processes, as well as the pathological ones, such as cell proliferation, apoptosis, and immune responses. Specifically, in the case of leukemia chemo-resistance, ncRNAs have been recognized to be responsible for modulating the initiation and progression of drug resistance. Herein, we comprehensively reviewed the role of ncRNAs, specifically its effect on molecular mechanisms and signaling pathways, in the development of leukemia drug resistance.

Long noncoding RNA expression in acute lymphoblastic leukemia: A systematic review

Long noncoding RNAs (lncRNAs), as gene expression modulators, are potential players in Acute Lymphoblastic Leukemia (ALL) pathogenesis. We systematically explored current literature on lncRNA expression in ALL to identify lncRNAs consistently reported as differentially expressed (DE) either in ALL versus controls or between ALL subtypes. By comparing articles that provided global expression data for DE lncRNAs in the ETV6::RUNX1-positive ALL subtype, we identified four DE lncRNAs in three independent studies (two versus other subtypes and one versus controls), showing concordant expression of LINC01013, CRNDE and lnc-KLF7-1. Additionally, LINC01503 was consistently downregulated on ALL versus controls. Within RT-qPCR studies, twelve lncRNA were DE in more than one source. Thus, several lncRNAs were supported as DE in ALL by multiple sources, highlighting their potential role as candidate biomarkers or therapeutic targets. Finally, as lncRNA annotation is rapidly expanding, standardization of reporting and nomenclature is urgently needed to improve data verifiability and compilation.

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.

Long Non-Coding RNA Signatures in Lymphopoiesis and Lymphoid Malignancies

Lymphoid cells play a critical role in the immune system, which includes three subgroups of T, B, and NK cells. Recognition of the complexity of the human genetics transcriptome in lymphopoiesis has revolutionized our understanding of the regulatory potential of RNA in normal lymphopoiesis and lymphoid malignancies. Long non-coding RNAs (lncRNAs) are a class of RNA molecules greater than 200 nucleotides in length. LncRNAs have recently attracted much attention due to their critical roles in various biological processes, including gene regulation, chromatin organization, and cell cycle control. LncRNAs can also be used for cell differentiation and cell fate, as their expression patterns are often specific to particular cell types or developmental stages. Additionally, lncRNAs have been implicated in lymphoid differentiation, such as regulating T-cell and B-cell development, and their expression has been linked to immune-associated diseases such as leukemia and lymphoma. In addition, lncRNAs have been investigated as potential biomarkers for diagnosis, prognosis, and therapeutic response to disease management. In this review, we provide an overview of the current knowledge about the regulatory role of lncRNAs in physiopathology processes during normal lymphopoiesis and lymphoid leukemia.

The Importance of Selected Dysregulated microRNAs in Diagnosis and Prognosis of Childhood B-Cell Precursor Acute Lymphoblastic Leukemia

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a frequent type of childhood hematological malignancy. The disease is classified into several subtypes according to genetic abnormalities. MicroRNAs (miRNAs) are involved in pathological processes (e.g., proliferation, apoptosis, differentiation). A miRNA is a group of short non-coding RNAs with relevant regulatory effects on gene expression achieved by suppression of the translation or degradation of messenger RNA (mRNA). These molecules act as tumor suppressors and/or oncogenes in the pathogenesis of pediatric leukemias. The characteristic features of miRNAs are their stable form and the possibility of secretion to the circulatory system. The role of miRNA in BCP-ALL pathogenesis is still emerging, but several studies have suggested using miRNA expression profiles as biomarkers for diagnosis, prognosis, and response to therapy in leukemia. The dysregulation of some miRNAs involved in childhood acute lymphoid leukemia, such as miR-155, miR-200c, miR-100, miR-181a, miR125b, and miR146a is discussed, showing their possible employment as therapeutic targets. In the current review, the capabilities of miRNAs in non-invasive diagnostics and their prognostic potential as biomarkers are presented.

The Promising Role of Non-Coding RNAs as Biomarkers and Therapeutic Targets for Leukemia

Early-stage leukemia identification is crucial for effective disease management and leads to an improvement in the survival of leukemia patients. Approaches based on cutting-edge biomarkers with excellent accuracy in body liquids provide patients with the possibility of early diagnosis with high sensitivity and specificity. Non-coding RNAs have recently received a great deal of interest as possible biomarkers in leukemia due to their participation in crucial oncogenic processes such as proliferation, differentiation, invasion, apoptosis, and their availability in body fluids. Recent studies have revealed a strong correlation between leukemia and the deregulated non-coding RNAs. On this basis, these RNAs are also great therapeutic targets. Based on these advantages, we tried to review the role of non-coding RNAs in leukemia. Here, the significance of several non-coding RNA types in leukemia is highlighted, and their potential roles as diagnostic, prognostic, and therapeutic targets are covered.

Specific lncRNA signatures discriminate childhood acute leukaemias: a pilot study

BACKGROUND

Long non-coding RNAs are RNAs longer than 200 bps that do not encode any proteins and are able to alter gene expression by acting on different steps of regulation, including DNA methylation and chromatin structure. They represent a class of biomarkers of crescent interest in the hematologic and oncologic fields. Recent studies showed that the expression levels of specific lncRNAs correlate with the prognosis of paediatric patients with Acute Lymphoblastic Leukaemia.

METHODS

We used NGS approaches to analyse the transcriptome of 9 childhood B-ALL patients and 6 childhood T-ALL patients, in comparison with B and T healthy lymphocytes from cord blood. We validate our findings both ex vivo, in a different cohort of 10 B-ALL and 10 T-ALL patients, and in silico using public datasets.

RESULTS

We characterised the lncRNA landscape for B-ALL, T-ALL, healthy B, and T cell progenitors. From the characterised signature, we selected candidate lncRNAs able to discriminate not only B-ALL and T-ALL from healthy subjects but also between the two types of leukaemia, and subsequently validated their potential as a diagnostic tool in an additional cohort of paediatric patients. We confirmed our finding with open access transcriptomic data, comparing ALL lncRNAs with AML lncRNA landscape as well. Finally, expression correlation analyses of T-ALL selected lncRNA biomarkers suggested a possible role in lymphocyte activation and the β-catenin signalling pathway for AC247036.1 and involvement in hedgehog signalling for HHIP-AS1.

CONCLUSIONS

Our work identified a lncRNA signature discriminating paediatric B-ALL and T-ALL from healthy subjects, between them and from AML. This study provides the keystone to future clinical studies determining the theragnostic value of the characterised long non coding transcriptome panorama in a clinical setting for childhood patient management.

Diagnostic and Therapeutic Implications of Long Non-Coding RNAs in Leukemia

Leukemia is a heterogenous group of hematological malignancies categorized in four main types (acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL). Several cytogenetic and molecular markers have become a part of routine analysis for leukemia patients. These markers have been used in diagnosis, risk-stratification and targeted therapy application. Recent studies have indicated that numerous regulatory RNAs, such as long non-coding RNAs (lncRNAs), have a role in tumor initiation and progression. When it comes to leukemia, data for lncRNA involvement in its etiology, progression, diagnosis, treatment and prognosis is limited. The aim of this review is to summarize research data on lncRNAs in different types of leukemia, on their expression pattern, their role in leukemic transformation and disease progression. The usefulness of this information in the clinical setting, i.e., for diagnostic and prognostic purposes, will be emphasized. Finally, how particular lncRNAs could be used as potential targets for the application of targeted therapy will be considered.

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.

Characterization of Long Non-coding RNA Signatures of Intracranial Aneurysm in Circulating Whole Blood

BACKGROUND AND OBJECTIVE

Long non-coding RNAs (lncRNAs) may serve as biomarkers for complex disease states, such as intracranial aneurysms. In this study, we investigated lncRNA expression differences in the whole blood of patients with unruptured aneurysms.

METHODS

Whole blood RNA from 67 subjects (34 with aneurysm, 33 without) was used for next-generation RNA sequencing. Differential expression analysis was used to define a signature of intracranial aneurysm-associated lncRNAs. To estimate the signature's ability to classify aneurysms and to identify the most predictive lncRNAs, we implemented a nested cross-validation pipeline to train classifiers using linear discriminant analysis. Ingenuity pathway analysis was used to study potential biological roles of differentially expressed lncRNAs, and lncRNA ontology was used to investigate ontologies enriched in signature lncRNAs. Co-expression correlation analysis was performed to investigate associated differential protein-coding messenger RNA expression.

RESULTS

Of 4639 detected lncRNAs, 263 were significantly different (p < 0.05) between the two groups, and 84 of those had an absolute fold-change ≥ 1.5. An eight-lncRNA signature (q < 0.35, fold-change ≥ 1.5) was able to separate patients with and without aneurysms on principal component analysis, and had an estimated accuracy of 70.9% in nested cross-validation. Bioinformatics analyses showed that networks of differentially expressed lncRNAs (p < 0.05) were enriched for cell death and survival, connective tissue disorders, carbohydrate metabolism, and cardiovascular disease. Signature lncRNAs shared ontologies that reflected regulation of gene expression, signaling, ubiquitin processing, and p53 signaling. Co-expression analysis showed correlations with messenger RNAs related to inflammatory responses.

CONCLUSIONS

Differential expression in whole blood lncRNAs is detectable in patients harboring aneurysms, and reflects expression/signaling regulation, and ubiquitin and p53 pathways. Following validation in larger cohorts, these lncRNAs may be potential diagnostic targets for aneurysm detection by blood testing.

Identification of a Seven-lncRNA-mRNA Signature for Recurrence and Prognostic Prediction in Relapsed Acute Lymphoblastic Leukemia Based on WGCNA and LASSO Analyses

Abnormal expressions of long noncoding RNAs (lncRNAs) and protein-encoding messenger RNAs (mRNAs) are important for the development of childhood acute lymphoblastic leukemia (ALL). This study developed an lncRNA-mRNA integrated classifier for the prediction of recurrence and prognosis in relapsed childhood ALL by using several transcriptome data. Weighted gene coexpression network analysis revealed that green, turquoise, yellow, and brown modules were preserved across the TARGET, GSE60926, GSE28460, and GSE17703 datasets, and they were associated with clinical relapse and death status. A total of 184 genes in these four modules were differentially expressed between recurrence and nonrecurrence samples. Least absolute shrinkage and selection operator analysis showed that seven genes constructed a prognostic signature (including one lncRNA: LINC00652 and six mRNAs: INSL3, NIPAL2, REN, RIMS2, RPRM, and SNAP91). Kaplan-Meier curve analysis observed that patients in the high-risk group had a significantly shorter overall survival than those of the low-risk group. Receiver operating characteristic curve analysis demonstrated that this signature had high accuracy in predicting the 5-year overall survival and recurrence outcomes, respectively. LINC00652 may function by coexpressing with the above prognostic genes (INSL3, SNAP91, and REN) and lipid metabolism-related genes (MIA2, APOA1). Accordingly, this lncRNA-mRNA-based classifier may be clinically useful to predict the recurrence and prognosis for childhood ALL. These genes represent new targets to explain the mechanisms for ALL.

Non-Coding RNA Signatures of B-Cell Acute Lymphoblastic Leukemia

Non-coding RNAs (ncRNAs) comprise a diverse class of non-protein coding transcripts that regulate critical cellular processes associated with cancer. Advances in RNA-sequencing (RNA-Seq) have led to the characterization of non-coding RNA expression across different types of human cancers. Through comprehensive RNA-Seq profiling, a growing number of studies demonstrate that ncRNAs, including long non-coding RNA (lncRNAs) and microRNAs (miRNA), play central roles in progenitor B-cell acute lymphoblastic leukemia (B-ALL) pathogenesis. Furthermore, due to their central roles in cellular homeostasis and their potential as biomarkers, the study of ncRNAs continues to provide new insight into the molecular mechanisms of B-ALL. This article reviews the ncRNA signatures reported for all B-ALL subtypes, focusing on technological developments in transcriptome profiling and recently discovered examples of ncRNAs with biologic and therapeutic relevance in B-ALL.

LncRNA-mRNA Co-Expression Analysis Identifies AL133346.1/CCN2 as Biomarkers in Pediatric B-Cell Acute Lymphoblastic Leukemia

Simple Summary

Dysregulation of noncoding RNAs has been described in numerous types of cancers and it has been associated with oncogenic or tumor suppressor activities. However, the signature of clinically relevant noncoding RNAs in pediatric B-cell acute lymphoblastic leukemia is still poorly understood. In a search for long non-coding RNAs that characterize pediatric B-cell acute lymphoblastic leukemia, we found that the long non-coding RNA AL133346.1 and a neighbouring protein-coding mRNA (CCN2) were significantly over-expressed in leukemia samples compared to healthy bone marrow. Survival analysis showed that patients with high CCN2 expression had a significantly better prognosis. These data suggest that AL133346.1/CCN2 could be useful for discriminating subtypes of leukemia and that CCN2 expression could predict the prognosis of pediatric patients with B-cell acute lymphoblastic leukemia.

Abstract

Pediatric acute B-cell lymphoblastic leukemia (B-ALL) constitutes a heterogeneous and aggressive neoplasia in which new targeted therapies are required. Long non-coding RNAs have recently emerged as promising disease-specific biomarkers for the clinic. Here, we identified pediatric B-ALL-specific lncRNAs and associated mRNAs by comparing the transcriptomic signatures of tumoral and non-tumoral samples. We identified 48 lncRNAs that were differentially expressed between pediatric B-ALL and healthy bone marrow samples. The most relevant lncRNA/mRNA pair was AL133346.1/CCN2 (previously known as RP11-69I8.3/CTGF), whose expression was positively correlated and increased in B-ALL samples. Their differential expression pattern and their strong correlation were validated in external B-ALL datasets (Therapeutically Applicable Research to Generate Effective Treatments, Cancer Cell Line Encyclopedia). Survival curve analysis demonstrated that patients with “high” expression levels of CCN2 had higher overall survival than those with “low” levels (p = 0.042), and this gene might be an independent prognostic biomarker in pediatric B-ALL. These findings provide one of the first detailed descriptions of lncRNA expression profiles in pediatric B-ALL and indicate that these potential biomarkers could help in the classification of leukemia subtypes and that CCN2 expression could predict the survival outcome of pediatric B-cell acute lymphoblastic leukemia patients.

Expression Profile of LncRNAs in Childhood Acute Lymphoblastic Leukemia: A Pilot Study

Background: Childhood acute lymphoblastic leukemia (ALL) explains 26% of pediatricmalignancies and is one of the leading causes of disease-related deaths in children. A novelmolecular class of non-coding genes, long non-coding RNAs (lncRNAs) having over 200nucleotides, have been defined as regulators of different cellular processes including pluripotency,oncogenesis, and transcription. It has been demonstrated that lncRNA transcription profilescan distinguish pre B-cell subtype of ALL accurately and act as early diagnostic and prognosticbiomarkers. Hence, the aim of this pilot study was the prior evaluation of expression profileof several lncRNA candidates including RP11-68I18.10, RP11-624C23.1, RP11-446E9, RP11-137H2.4, and RP11-203E8 in patients with ALL. Methods: In this study, 80 blood samples were obtained from patients, definitely diagnosed bypathologists with ALL, and from healthy subjects. Total RNA was extracted from blood samples,and cDNA was synthesized. Real-time PCR was applied to determine the expression of lncRNAs.A P-value of 0.010 was considered statistically significant. Results: Our findings revealed that the expression levels of lncRNAs RP11-624C23.1, RP11-446E9, RP11-137H2.4, RP11-68I18.10, and RP11-203E8 were significantly decreased in ALLsamples compared to those of healthy samples (P<0.0001, P =0.0616, P =0.0292, P<0.0001, andP = 0.0007). Moreover, the relationship between these five lncRNA expression changes and theimmunophenotype in ALL patients was not significant. Conclusion: The dysregulation of lncRNAs in ALL samples could provide a novel and interestingpossibility for early diagnosis and prognosis, as well as mastering the treatment of ALL.

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.

The role of long non-coding RNAs and downstream signaling pathways in leukemia progression

The study of long non-coding RNAs (lncRNA) is a newly established field and our knowledge about them is rapidly growing. These kinds of RNAs are unchanged parts of the genome throughout evolution, that modulate cell growth, differentiation, and apoptosis during diverse physiological and pathological processes including leukemia development. They have the capability to be useful biomarkers for the diagnosis, clinical typing, prognosis, as well as potential therapeutic targets. In this study, we summarized the role of lncRNAs in the expression and function of white blood cells and oncogenic transformation into four main types of leukemia.

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.

Inflammation and tissue homeostasis: the NF-κB system in physiology and malignant progression

Disruption of tissue function activates cellular stress which triggers a number of mechanisms that protect the tissue from further damage. These mechanisms involve a number of homeostatic modules, which are regulated at the level of gene expression by the transactivator NF-κB. This transcription factor shifts between activation and repression of discrete, cell-dependent gene expression clusters. Some of its target genes provide feedback to NF-κB itself, thereby strengthening the inflammatory response of the tissue and later terminating inflammation to facilitate restoration of tissue homeostasis. Disruption of key feedback modules for NF-κB in certain cell types facilitates the survival of clones with genomic aberrations, and protects them from being recognized and eliminated by the immune system, to enable thereby carcinogenesis.

Drug Resistance Biomarkers and Their Clinical Applications in Childhood Acute Lymphoblastic Leukemia

Biomarkers are biological molecules found in body fluids or tissues, which can be considered as indications of a normal or abnormal process, or of a condition or disease. There are various types of biomarkers based on their application and molecular alterations. Treatment-sensitivity or drug resistance biomarkers include prognostic and predictive molecules with utmost importance in selecting appropriate treatment protocols and improving survival rates. Acute lymphoblastic leukemia (ALL) is the most prevalent hematological malignancy diagnosed in children with nearly 80% cure rate. Despite the favorable survival rates of childhood ALL (chALL), resistance to chemotherapeutic agents and, as a consequence, a dismal prognosis develops in a significant number of patients. Therefore, there are urgent needs to have robust, sensitive, and disease-specific molecular prognostic and predictive biomarkers, which could allow better risk classification and then better clinical results. In this article, we review the currently known drug resistance biomarkers, including somatic or germ line nucleic acids, epigenetic alterations, protein expressions and metabolic variations. Moreover, biomarkers with potential clinical applications are discussed.

Predicting lncRNA-disease associations using network topological similarity based on deep mining heterogeneous networks

A kind of noncoding RNA with length more than 200 nucleotides named long noncoding RNA (lncRNA) has gained considerable attention in recent decades. Many studies have confirmed that human genome contains many thousands of lncRNAs. LncRNAs play significant roles in many important biological processes, including complex disease diagnosis, prognosis, prevention and treatment. For some important diseases such as cancer, lncRNAs have been novel candidate biomarkers. However, the role of lncRNAs in human diseases is still in its infancy, and only a small part of lncRNA-disease associations have been experimentally verified. Predicting lncRNA-disease association is an important way to understand the mechanism and function of lncRNA involved in diseases to enrich the annotations of lncRNA. Therefore, it is urgent to prioritize lncRNAs potentially associated with diseases. Biological system is a highly complex heterogenous network involved different molecules. Therefore, the algorithms based on network methods have been extensively applied in information fields which can provide a quantifiable characterization for the networks characterizing multifarious biological systems. A heterogeneous network topology possessing abundant interactions between biomedical entities is rarely utilized in similarity-based methods for predicting lncRNA-disease associations based on the array of varying features of lncRNAs and diseases. DeepWalk, encoding the relations of nodes in a continuous vector space, is an extension of language model and unsupervised learning from sequence-based word to network. In this article, we present a novel lncRNA-disease association prediction method based on DeepWalk, which enhances the existing association discovery methods through a topology-based similarity measure. We integrate the heterogeneous data to construct a Linked Tripartite Network which is a heterogeneous network containing three types od nodes which generated from bioinformatics linked datasets and use DeepWalk method to extract topological structure features of the nodes in the linked tripartite network for calculating similarities. Our proposed method can be separated into the following steps: Firstly, we integrate heterogeneous data to construct a Linked Tripartite Network: containing the topological interactions of known lncRNA-disease, lncRNA-microRNA and microRNA-disease. Secondly, the topological structure features of the nodes are extracted based on DeepWalk. Thirdly, similarity scores of disease-disease pairs and lncRNA-lncRNA pairs are computed based on the topology of this network. Finally, new lncRNA and disease associations are discovered by rule-based inference method with lncRNA-lncRNA similarities. Our proposed method shows superior predictive performance for prediction of lncRNA-disease associations based on topological similarity from heterogenous network. The AUC value is used to show the performance of our method. The similarity measurement using network topology based on DeepWalk provide a novel perspective which is different from the similarity derived from sequence or structure information. Availability: All the data and codes are freely availability at: https://github.com/Pengeace/lncRNA-disease-link.

Comprehensive Analysis of lncRNAs and circRNAs Reveals the Metabolic Specialization in Oxidative and Glycolytic Skeletal Muscles

The biochemical and functional differences between oxidative and glycolytic muscles could affect human muscle health and animal meat quality. However, present understanding of the epigenetic regulation with respect to lncRNAs and circRNAs is rudimentary. Here, porcine oxidative and glycolytic skeletal muscles, which were at the growth curve inflection point, were sampled to survey variant global expression of lncRNAs and circRNAs using RNA-seq. A total of 4046 lncRNAs were identified, including 911 differentially expressed lncRNAs (p < 0.05). The cis-regulatory analysis identified target genes that were enriched for specific GO terms and pathways (p < 0.05), including the oxidation-reduction process, glycolytic process, and fatty acid metabolic. All these were closely related to different phenotypes between oxidative and glycolytic muscles. Additionally, 810 circRNAs were identified, of which 137 were differentially expressed (p < 0.05). Interestingly, some circRNA-miRNA-mRNA networks were found, which were closely linked to muscle fiber-type switching and mitochondria biogenesis in muscles. Furthermore, 44.69%, 39.19%, and 54.01% of differentially expressed mRNAs, lncRNAs, and circRNAs respectively were significantly enriched in pig quantitative trait loci (QTL) regions for growth and meat quality traits. This study reveals a mass of candidate lncRNAs and circRNAs involved in muscle physiological functions, which may improve understanding of muscle metabolism and development from an epigenetic perspective.

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.

Advances in biology of acute lymphoblastic leukemia (ALL) and therapeutic implications

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer and also occurs in adults. Although the outcomes of multi-agent chemotherapy regimens have greatly improved, high toxicity and relapses in many patients necessitate the development of novel therapeutic approaches. Advances in molecular profiling and cytogenetics have identified a broad range of genetic abnormalities, including gene mutations, chromosome translocations and aneuploidy, which has provided a more comprehensive understanding of the biology and pathogenesis of ALL. This understanding has also led to new targeted therapeutic approaches, including the use of selective small molecule inhibitors, nucleic acid-based therapies and immune-based therapies mediated by specific monoclonal antibodies and cellular immunotherapy, which are poised to revolutionize the treatment of various ALL subtypes. The main focus of this review is to highlight the latest advances in ALL biology, including the identification of prognostic factors and putative therapeutic targets. We also review the current status of, and ongoing progress in, the development of targeted therapies for ALL.

TCF7L2 activated HOXA-AS2 decreased the glucocorticoid sensitivity in acute lymphoblastic leukemia through regulating HOXA3/EGFR/Ras/Raf/MEK/ERK pathway

Acute lymphoblastic leukemia (ALL) is characterized by abnormal lymphoblasts accumulation in the bone marrow and blood. Despite great efforts have been made in exploring novel therapeutic method, the prognosis of children with ALL is still unsatisfied. Glucocorticoid (GC) resistance is a great obstacle for the clinical treatment of ALL. Therefore, it is essential to investigate the molecular mechanism underlying the GC resistance. According to previous reports, long noncoding RNAs (lncRNAs) are involved in drug resistance of various human cancers. LncRNA HOXA cluster antisense RNA2 (HOXA-AS2) has been reported in several human malignancies due to its oncogenic property. However, the molecular mechanism of HOXA-AS2 involved in the GC resistance of ALL still needs to be further clarified. At first, we found that lncRNA HOXA-AS2 was highly expressed both in prednisone insensitive ALL cell lines and patient samples. Gain or loss-of-function assays revealed that HOXA-AS2 enhanced GC resistance via promoting cell proliferation and inhibiting cell apoptosis. Furthermore, we validated that HOXA-AS2 upregulated HOXA3, thereby activating EGFR/Ras/Raf/MEK/ERK signaling pathway. Our findings showed that HOXA-AS2 may be a potential therapeutic target for ALL patients with poor GC resistance.

Very long intergenic non-coding RNA transcripts and expression profiles are associated to specific childhood acute lymphoblastic leukemia subtypes

Very long intergenic non-coding RNAs (vlincRNAs) are a novel class of long transcripts (~50 kb to 1 Mb) with cell type- or cancer-specific expression. We report the discovery and characterization of 256 vlincRNAs from a cohort of 64 primary childhood pre-B and pre-T acute lymphoblastic leukemia (cALL) samples, of which 61% are novel and specifically expressed in cALL. Validation was performed in 35 pre-B and pre-T cALL primary samples. We show that their expression is cALL immunophenotype and molecular subtype-specific and correlated with epigenetic modifications on their promoters, much like protein-coding genes. While the biological functions of these vlincRNAs are still unknown, our results suggest they could play a role in cALL etiology or progression.

Long Non-Coding RNAs Guide the Fine-Tuning of Gene Regulation in B-Cell Development and Malignancy

With the introduction of next generation sequencing methods, such as RNA sequencing, it has become apparent that alterations in the non-coding regions of our genome are important in the development of cancer. Particularly interesting is the class of long non-coding RNAs (lncRNAs), including the recently described subclass of circular RNAs (circRNAs), which display tissue- and cell-type specific expression patterns and exert diverse regulatory functions in the cells. B-cells undergo complex and tightly regulated processes in order to develop from antigen naïve cells residing in the bone marrow to the highly diverse and competent effector cells circulating in peripheral blood. These processes include V(D)J recombination, rapid proliferation, somatic hypermutation and clonal selection, posing a risk of malignant transformation at each step. The aim of this review is to provide insight into how lncRNAs including circRNAs, participate in normal B-cell differentiation, and how deregulation of these molecules is involved in the development of B-cell malignancies. We describe the prognostic value and functional significance of specific deregulated lncRNAs in diseases such as acute lymphoblastic leukemia, chronic lymphocytic leukemia, mantle cell lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, Burkitt lymphoma and multiple myeloma, and we provide an overview of the current knowledge on the role of circRNAs in these diseases.

Long Noncoding RNA GAPLINC Promotes Cells Migration and Invasion in Colorectal Cancer Cell by Regulating miR-34a/c-MET Signal Pathway

BACKGROUND

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) has been detected in colorectal cancer (CRC) cells and reportedly performs many functions related to tumor proliferation and metastasis. Aim The present study aimed to comprehensively explore the biological functions of GAPLINC and their underlying mechanism in CRC cell.

METHODS

The human cancer LncRNA PCR array was used to detect the differentially expressed long noncoding RNAs in human CRC samples. Real-time PCR, dual-luciferase assay, RNA pull-down assay, Transwell assay, and western blot analysis were performed to explore the molecular mechanism underlying GAPLINC functions related to migration and invasion of a human CRC cell line (HCT116).

RESULTS

Compared to the non-cancerous tissues, GAPLINC expression was obviously increased in CRC tissues. In HCT116, silencing of GAPLINC weakened cell migration and invasion, while overexpression of GAPLINC significantly promoted cell migration and invasion. Through dual-luciferase, RNA pull-down, and Transwell assays, we verified that miR-34a was the downstream molecule of GAPLINC and that miR-34a negatively regulated the migration and invasion of HCT116 cell. Furthermore, we found that GAPLINC positively regulated the miR-34a target gene c-MET in CRC tissues.

CONCLUSIONS

Our findings revealed that GAPLINC was up-regulated in CRC tissues and was involved in the migration and invasion of CRC cells by regulating miR-34a/c-MET signaling pathway.

Role of miRNAs in treatment response and toxicity of childhood acute lymphoblastic leukemia

Childhood acute lymphoblastic leukemia survival rates have increased remarkably during last decades due, in part, to intensive treatment protocols. However, therapy resistance and toxicity are still two important barriers to survival. In this context, pharmacoepigenetics arises as a tool to identify new predictive markers, required to guide clinicians on risk stratification and dose individualization. The present study reviews current evidence about miRNA implication on childhood acute lymphoblastic leukemia therapy resistance and toxicity. A total of 12 studies analyzing differential miRNA expression in relation to drug resistance and six studies exploring the association between miRNAs-related SNPs and drug-induced toxicities were identified. We pointed out to miR-125b together with miR-99a and/or miR-100 overexpression as markers of vincristine resistance and rs2114358 in mir-1206 as mucositis marker as the most promising results.

Knockdown of long non-coding RNA MALAT1 inhibits growth and motility of human hepatoma cells via modulation of miR-195

The metastasis-associated lung adenocarcinoma transcription 1 (Malat1) is a long non-coding RNA (lncRNA), exerts oncogenic role in multiple cancers, including hepatocellular carcinoma (HCC). This study was aimed to investigate its posttranscriptional regulation in HCC cells. RT-PCR was performed to monitor the expression levels of Malat1 in normal liver and HCC cell lines. The expression of Malat1, microRNA (miR)-195, and epidermal growth factor receptor (EGFR) in HepG2 and MHCC97 cells was respectively or synchronously altered by transfection. Then the changes in cell viability, apoptotic cell rate, cell cycle distribution, migration, and invasion were respectively assessed. As a result, we found that Malat1 was highly expressed in HCC cell lines when compared to normal liver cells. Malat1 silence suppressed HCC cells viability, migration and invasion, induced apoptosis, and arrested more cells in G0/G1 phase. Malat1 acted as a circular endogenous RNA (ceRNA) for miR-195. Malat1 silence could not suppress HCC cell growth and motility when miR-195 was knocked down. EGFR was a direct target of miR-195. miR-195 overexpression could not suppress HCC cell growth and motility when the 3'UTR site of EGFR was overexpressed. Furthermore, Malat1 silence blocked the activation of PI3K/AKT and JAK/STAT pathways, while EGFR overexpression activated them. Our study demonstrates Malat1-miR-195-EGFR axis plays a critical role in HCC cells which provided a better understanding of Malat1 in HCC.

LncRNAs downregulated in childhood acute lymphoblastic leukemia modulate apoptosis, cell migration, and DNA damage response

Childhood acute lymphoblastic leukemia (cALL) accounts for 25% of pediatric cancers and is one of the leading causes of disease-related death in children. Although long non-coding RNAs (lncRNAs) have been implicated in cALL etiology, progression, and treatment response, little is known about their exact functional role. We had previously sequenced the whole transcriptome of 56 cALL patients and identified lncRNA transcripts specifically silenced in tumoral cells. Here we investigated the impact of restoring the expression of three of these (RP11-624C23.1, RP11-203E8, and RP11-446E9) in leukemic cell lines had dramatic impact on cancer hallmark cellular phenotypes such as apoptosis, cell proliferation and migration, and DNA damage response. Interestingly, both RP11-624C23.1 and RP11-203E8 had very similar impacts on DNA damage response, specifically displaying lower γ-H2A.X and higher apoptosis levels than control cells in response to genotoxic stress. These results indicate that silencing RP11-624C23.1 or RP11-203E8 could provide a selective advantage to leukemic cells by increasing resistance to genotoxic stress, possibly by modulating the DDR pathway. Since genotoxic agents are fundamental parts of antineoplastic treatment, further investigation of the mechanisms these lncRNAs impact would provide novel and interesting avenues for overcoming treatment resistance.

Long non-coding RNA CCAT1/miR-148a axis promotes osteosarcoma proliferation and migration through regulating PIK3IP1

Osteosarcoma is the most frequent type of malignant primary bone tumor. Although many efforts have been made, the survival rate of osteosarcoma still remains unsatisfied. Long non-coding RNAs (lncRNAs) have been demonstrated to be associated with many diseases including tumors, and involved in the regulation of a wide array of pathophysiological processes. Colon-cancer-associated transcript-1 (CCAT1) was first identified in colon cancer and has subsequently been reported to perform many functions in tumor progression. The present study aimed to comprehensively explore the biological functions of CCAT1 and its underlying mechanism in osteosarcoma cells. Our findings revealed that CCAT1 was upregulated in osteosarcoma tissues and cells, and was involved in the proliferation and migration of osteosarcoma via regulating miR-148a/phosphatidyl inositol 3-kinase interacting protein 1 (PIK3IP1) signal pathway.