Specific expression of novel long non-coding RNAs in high-hyperdiploid childhood acute lymphoblastic leukemia

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.

CircRNAome of Childhood Acute Lymphoblastic Leukemia: Deciphering Subtype-Specific Expression Profiles and Involvement in TCF3::PBX1 ALL

Childhood B-cell acute lymphoblastic leukemia (B-ALL) is a heterogeneous disease comprising multiple molecular subgroups with subtype-specific expression profiles. Recently, a new type of ncRNA, termed circular RNA (circRNA), has emerged as a promising biomarker in cancer, but little is known about their role in childhood B-ALL. Here, through RNA-seq analysis in 105 childhood B-ALL patients comprising six genetic subtypes and seven B-cell controls from two independent cohorts we demonstrated that circRNAs properly stratified B-ALL subtypes. By differential expression analysis of each subtype vs. controls, 156 overexpressed and 134 underexpressed circRNAs were identified consistently in at least one subtype, most of them with subtype-specific expression. TCF3::PBX1 subtype was the one with the highest number of unique and overexpressed circRNAs, and the circRNA signature could effectively discriminate new patients with TCF3::PBX1 subtype from others. Our results indicated that NUDT21, an RNA-binding protein (RBP) involved in circRNA biogenesis, may contribute to this circRNA enrichment in TCF3::PBX1 ALL. Further functional characterization using the CRISPR-Cas13d system demonstrated that circBARD1, overexpressed in TCF3::PBX1 patients and regulated by NUDT21, might be involved in leukemogenesis through the activation of p38 via hsa-miR-153-5p. Our results suggest that circRNAs could play a role in the pathogenesis of childhood B-ALL.

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 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.

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.

Identification of new ETV6 modulators through a high-throughput functional screening

ETV6 transcriptional activity is critical for proper blood cell development in the bone marrow. Despite the accumulating body of evidence linking ETV6 malfunction to hematological malignancies, its regulatory network remains unclear. To uncover genes that modulate ETV6 repressive transcriptional activity, we performed a specifically designed, unbiased genome-wide shRNA screen in pre-B acute lymphoblastic leukemia cells. Following an extensive validation process, we identified 13 shRNAs inducing overexpression of ETV6 transcriptional target genes. We showed that the silencing of AKIRIN1, COMMD9, DYRK4, JUNB, and SRP72 led to an abrogation of ETV6 repressive activity. We identified critical modulators of the ETV6 function which could participate in cellular transformation through the ETV6 transcriptional network.

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We develop a genome-wide shRNAs screen for ETV6 modulators

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The screen uncovered 13 novel putative ETV6 modulator genes

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The modulators demonstrated a broad impact on the ETV6 transcriptional network

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T-ALL cells results suggest modulators are conserved in other cellular contexts

Differential mRNA and long noncoding RNA expression profiles in pediatric B-cell acute lymphoblastic leukemia patients

BACKGROUND

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nucleotides (nt) that are involved in the pathogenesis and development of various cancers including B cell acute lymphoblastic leukemia (B-ALL). To determine the potential roles of lncRNAs involved in pathogenesis of B-ALL, we analyzed the expression profile of lncRNAs and mRNAs in B-ALL, respectively, and constructed lncRNAs/mRNAs interaction network.

METHODS

We performed RNA sequencing of 10 non-leukemic blood disease donors and 10 B-ALL patients for Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Interactions among mRNAs were predicted using the STRING database. Quantitative real time PCR (qRT-PCR) was performed to verify the RNA-seq data of lncRNAs and mRNAs. Potential functions of subtype-specific lncRNAs were determined by using coexpression-based analysis on distally (trans-pattern) located protein-coding genes.

RESULTS

A total of 1813 differentially expressed transcripts (DETs) and 2203 lncRNAs were identified. Moreover, 10 dysregulated lncRNAs and 10 mRNAs were randomly selected, and further assessed by RT-qPCR in vitro. Go and KEGG analysis demonstrated that the differentially expressed mRNAs were most closely associated with myeloid leukocyte activation and in transcriptional misregulation in cancer, respectively. In addition, co-expression analysis demonstrated that these lncRNAs, including MSTRG.27994.3, MSTRG.21740.1, ENST00000456341, MSTRG.14224.1 and MSTRG.20153.1, may mediate the pathogenesis and development of B-ALL via lncRNA-mRNA network interactions.

CONCLUSIONS

These results showed that several mRNAs and lncRNAs are aberrantly expressed in the bone marrow of B-ALL patients and play potential roles in B-ALL development, and be useful for diagnostic and/or prognostic purposes in pediatric B-ALL.

DATA AVAILABILITY

The datasets used during our study are available through HARVARD Dataverse Persistent ID doi: https://doi.org/10.7910/DVN/LK9T4Z .

The lncRNA TEX41 is upregulated in pediatric B-Cells Acute Lymphoblastic Leukemia and it is necessary for leukemic cell growth

Background

Long non-coding RNAs (lncRNAs) represent a diverse class of RNAs involved in the regulation of various physiological and pathological cellular processes, including transcription, intracellular trafficking, and chromosome remodeling. LncRNAs deregulation was linked to the development and progression of various cancer types, such as acute leukemias. In this context, lncRNAs were also evaluated as a novel class of biomarkers for cancer diagnosis and prognosis. Here, we analyzed TEX41 in childhood B cell acute lymphoid leukemia (B-ALL).

Methods

Total RNA was extracted from pediatric B-ALL patients (at diagnosis and after induction of therapy) and from healthy subjects. Total RNA was also extracted from different leukemia cell line models. The expression level of TEX41 was evaluated by q-RT-PCR. Also, the dataset deposited by St. Jude Children’s Research Hospital was consulted. Furthermore, the silencing of TEX41 in RS4;11 cell line was obtained by 2′-Deoxy, 2′Fluroarabino Nucleic Acids (2′F-ANAs) Oligonucleotides, and the effect on cell proliferation was evaluated. Cell cycle progression and its regulators were analyzed by flow cytometry and immunoblotting.

Results

We exploited the St Jude Cloud database and found that TEX41 is a lncRNA primarily expressed in the case of B-ALL (n = 79) while its expression levels are low/absent for T-cell ALL (n = 25) and acute myeloid leukemia (n = 38). The association of TEX41 with B-ALL was confirmed by real-time PCR assays. TEX41 disclosed increased expression levels in bone marrow from patients with B-ALL at diagnosis, while its expression levels became low or absent when retested in Bone Marrow cells of the same patient after 1 month of induction therapy. Also, silencing experiments performed on RS4;11 cells showed that TEX41 downregulation impaired in vitro leukemic cell growth determining their arrest in the G2-M phase and the deregulation of cell cycle proteins.

Conclusions

Our findings highlight that TEX41 is an upregulated lncRNA in the case of B-ALL and this feature makes it a novel potential biomarker for the diagnosis of this leukemia subtype in pediatric patients. Finally, TEX41 expression seems to be critical for leukemic proliferation, indeed, silencing experiments targeting TEX41 mRNA in the RS4;11 cell line hampered in vitro cell growth and cell cycle progression, by inducing G2-M arrest as confirmed propidium iodide staining and by the upregulation of p53 and p21 proteins.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-021-00307-7.

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.

Role of rs10406069 in miR-5196 in hyperdiploid childhood acute lymphoblastic leukemia

Aim: To determine the role of single nucleotide polymorphisms (SNPs) in noncoding RNAs in childhood acute lymphoblastic leukemia (ALL) subtypes. Materials & methods: We screened all SNPs in 130 pre-miRNA genes to assess their role in the susceptibility of the most common subtypes of ALL: hyperdiploid and ETV6-RUNX1. Results: In two independent cohorts, we found a significant association between rs10406069 in miR-5196 and the risk of developing hyperdiploid ALL. This observation could be explained by the impact of the SNP on miR-5196 expression and in turn, in its target genes. Indeed, rs10406069 was associated with expression changes in SMC1A, a gene involved in sister chromatin cohesion. Conclusion: rs10406069 in miR-5196 may have a relevant role in hyperdiploid ALL risk.

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.

LncRNA CRNDE Promotes the Progression of B-cell Precursor Acute Lymphoblastic Leukemia by Targeting the miR-345-5p/CREB Axis

The imbalance between the proliferation and apoptosis of B-cell precursors is an important contributor to the pathogenesis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), while its specific regulatory mechanism remains perplexing. This study aimed to expound the underlying mechanism of the proliferation and apoptosis of BCP-ALL cells from the perspective of non-coding RNA. In this study, long non-coding RNA colorectal neoplasia differentially expressed (LncRNA CRNDE) was upregulated in the bone marrow of BCP-ALL patients and BCP-ALL cell lines (NALM-6 and RS4;11). Functionally, LncRNA CRNDE knockdown restrained cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. The subsequent investigation confirmed that LncRNA CRNDE bound to miR-345-5p and negatively regulated miR-345-5p expression. The overexpression of miR-345-5p suppressed cell proliferation and boosted cell apoptosis in NALM-6 and RS4;11 cells. Further experiments revealed that miR-345-5p downregulated cyclic AMP response element-binding protein (CREB) expression by targeting its mRNA directly. CREB overexpression reversed the effect of miR-345-5p mimic on cell proliferation and apoptosis in NALM-6 and RS4;11 cells. Finally, in vivo experiments showed that LncRNA CRNDE knockdown prolonged the survival of mice xenotransplanted with NALM-6 cells. In conclusion, LncRNA CRNDE upregulated CREB expression by suppressing miR-345-5p, thus promoting cell proliferation and reducing cell apoptosis in BCP-ALL.

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.

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.

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.

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.

Epigenetics in pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. ALL arises from the malignant transformation of progenitor B- and T-cells in the bone marrow into leukemic cells, but the mechanisms underlying this transformation are not well understood. Recent technical advances and decreasing costs of methods for high-throughput DNA sequencing and SNP genotyping have stimulated systematic studies of the epigenetic changes in leukemic cells from pediatric ALL patients. The results emerging from these studies are increasing our understanding of the epigenetic component of leukemogenesis and have demonstrated the potential of DNA methylation as a biomarker for lineage and subtype classification, prognostication, and disease progression in ALL. In this review, we provide a concise examination of the epigenetic studies in ALL, with a focus on DNA methylation and mutations perturbing genes involved in chromatin modification, and discuss the future role of epigenetic analyses in research and clinical management of ALL.