Expression of the long non-coding RNA TCL6 is associated with clinical outcome in pediatric B-cell acute lymphoblastic leukemia

Transcriptome organization of white blood cells through gene co-expression network analysis in a large RNA-seq dataset

Gene co-expression network analysis enables identification of biologically meaningful clusters of co-regulated genes (modules) in an unsupervised manner. We present here the largest study conducted thus far of co-expression networks in white blood cells (WBC) based on RNA-seq data from 624 individuals. We identify 41 modules, 13 of them related to specific immune-related functions and cell types (e.g. neutrophils, B and T cells, NK cells, and plasmacytoid dendritic cells); we highlight biologically relevant lncRNAs for each annotated module of co-expressed genes. We further characterize with unprecedented resolution the modules in T cell sub-types, through the availability of 95 immune phenotypes obtained by flow cytometry in the same individuals. This study provides novel insights into the transcriptional architecture of human leukocytes, showing how network analysis can advance our understanding of coding and non-coding gene interactions in immune system cells.

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.

Mechanistic insights into FEN1-mediated drug sensitivity and risk signature in colon cancer: An integrative bioinformatics study

The overexpression of Flap endonuclease 1 (FEN1) has been implicated in drug resistance and prognosis across various cancer types. However, the precise role of FEN1 in colon cancer remains to be fully elucidated. In this study, we employed comprehensive datasets from The Cancer Genome Atlas, Gene Expression Omnibus, and Human Protein Atlas to examine FEN1 expression and assess its correlation with clinical pathology and prognosis in colon cancer. We utilized the pRRophetic algorithm to evaluate drug sensitivity and performed differential expression analysis to identify genes associated with FEN1-mediated drug sensitivity. Gene set enrichment analysis was conducted to further investigate these genes. Additionally, single-cell sequencing analysis was employed to explore the relationship between FEN1 expression and functional states. Cox regression analysis was implemented to construct a prognostic model, and a nomogram for prognosis was developed. Our analysis of The Cancer Genome Atlas and Gene Expression Omnibus datasets revealed a significant upregulation of FEN1 in colon cancer. However, while FEN1 expression showed no notable correlation with prognosis, it displayed associations with metastasis. Single-cell sequencing analysis further confirmed a positive correlation between FEN1 expression and colon cancer metastasis. Furthermore, we detected marked discrepancies in drug responsiveness between the High_FEN1 and Low_FEN1 groups, identifying 342 differentially expressed genes. Enrichment analysis showed significant suppression in processes related to DNA replication, spliceosome, and cell cycle pathways in the Low_FEN1 group, while the calcium signaling pathway, cAMP signaling pathway, and other pathways were activated. Of the 197 genes differentially expressed and strongly linked to FEN1 expression, 39 were significantly implicated in colon cancer prognosis. Finally, we constructed a risk signature consisting of 5 genes, which, when combined with drug treatment and pathological staging, significantly improved the prediction of colon cancer prognosis. This study offers novel insights into the interplay among FEN1 expression levels, colon cancer metastatic potential, and sensitivity to therapeutic agents. Furthermore, we successfully developed a multi-gene prognostic risk signature derived from FEN1.

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.

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.

Targeting the lncRNA DUXAP8/miR-29a/PIK3CA Network Restores Doxorubicin Chemosensitivity via PI3K-AKT-mTOR Signaling and Synergizes With Inotuzumab Ozogamicin in Chemotherapy-Resistant B-Cell Acute Lymphoblastic Leukemia

Purpose

This study aimed to determine the expression profiles of long non-coding RNA (lncRNA), microRNA (miRNA), and mRNA in chemotherapy-resistant B-cell acute lymphoblastic leukemia (B-ALL).

Methods

LncRNA, miRNA, and mRNA profiles were assessed by RNA-seq in diagnostic bone marrow samples from 6 chemotherapy-resistant and 6 chemotherapy-sensitive B-ALL patients. The lncRNA DUXAP8/miR-29a/PIK3CA signaling network was identified as the most dysregulated in chemoresistant patient samples, and its effect on cellular phenotypes, PI3K-AKT-mTOR signaling, and chemosensitivity of doxorubicin (Dox)-resistant Nalm-6 (N6/ADR), and Dox-resistant 697 (697/ADR) cells were assessed. Furthermore, its synergy with inotuzumab ozogamicin treatment was investigated.

Results

1,338 lncRNAs, 75 miRNAs, and 1620 mRNAs were found to be dysregulated in chemotherapy-resistant B-ALL in comparison to chemotherapy-sensitive B-ALL patient samples. Through bioinformatics analyses and RT-qPCR validation, the lncRNA DUXAP8/miR-29a/PIK3CA network and PI3K-AKT-mTOR signaling were identified as significantly associated with B-ALL chemotherapy resistance. In N6/ADR and 697/ADR cells, LncRNA DUXAP8 overexpression and PIK3CA overexpression induced proliferation and inhibited apoptosis, and their respective knockdowns inhibited proliferation, facilitated apoptosis, and restored Dox chemosensitivity. MiR-29a was shown to affect the lncRNA DUXAP8/PIK3CA network, and luciferase reporter gene assay showed direct binding between lncRNA DUXAP8 and miR-29a, as well as between miR-29a and PIK3CA. Targeting lncRNA DUXAP8/miR-29a/PIK3CA network synergized with inotuzumab ozogamicin's effect on N6/ADR and 697/ADR cells.

Conclusion

Targeting the lncRNA DUXAP8/miR-29a/PIK3CA network not only induced an apoptotic effect on Dox-resistant B-ALL and restored Dox chemosensitivity via PI3K-AKT-mTOR signaling but also showed synergism with inotuzumab ozogamicin treatment.

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 .

Expression and clinical significance of lncRNA TCL6 in serum of patients with preeclampsia

Preeclampsia is a common syndrome in pregnancy and a leading cause of mortality of pregnant females and their infants. To investigate the diagnostic and prognostic utility of lncRNA T-cell leukemia/lymphoma 6 (TCL6) in patients with preeclampsia, 120 singleton pregnant females with preeclampsia and another 100 healthy pregnant control subjects were analyzed in the present study. The expression of lncRNA TCL6 in the serum of the included patients was detected. Receiver operating characteristic curve analysis was applied to evaluate the efficiency of lncRNA TCL6 in terms of preeclampsia diagnosis and grading. Kaplan-Meier analysis was adopted to assess the effect of lncRNA TCL6 expression on the rate of adverse pregnancy. Multivariate logistic regression was used to determine high-risk factors of adverse pregnancy. The results indicated that lncRNA TCL6 was significantly increased in the serum of patients with preeclampsia. Furthermore, TCL6 was elevated in subgroups of patients with early-onset or severe preeclampsia and with Haemolysis, Elevated Liver enzymes and Low Platelet count syndrome in comparison with other patients with preeclampsia. High expression of TCL6 in pregnant females corresponded to a higher rate of adverse pregnancy outcomes. Severe preeclampsia, early-onset preeclampsia and high TCL6 expression were identified as independent risk factors for adverse pregnancy outcomes. For each unit increase in TCL6 expression, a 9.5-fold increase of the risk of adverse maternal and fetal outcomes was determined. Collectively, high expression of lncRNA TCL6 may assist the diagnosis and grading of preeclampsia and may be adopted as an independent risk factor for adverse pregnancy outcomes.

LINC00265/miR-4500 Axis Accelerates Acute Lymphoblastic Leukemia Progression by Enhancing STAT3 Signals

Background

Long noncoding RNA LINC00265 or miR-4500 is involved in the pathogenesis of many cancers. However, their functions in acute lymphoblastic leukemia (ALL) remain unknown. In this study, we investigated how LINC00265 and miR-4500 regulate the malignant characteristics of ALL.

Methods

Real-time PCR was used in examining the expression of LINC00265 in ALL cell lines and blood of patients with ALL. Cell proliferation, cell migration, and xenograft tumor assays were performed to verify the function of LINC00265 subjected to overexpressing and silencing experiments. The ceRNA mechanism with LINC00265/miR-4500/STAT3 was investigated through luciferase and RNA pull-down assays. Finally, the function of the LINC00265/miR-4500/STAT3 axis subjected to overexpressing and silencing assays was determined through cell proliferation, cell migration, and xenograft tumor assays.

Results

LINC00265 was highly expressed in ALL cell lines and blood of patients with ALL and facilitated the proliferation, migration, invasion, and growth of xenograft tumors of ALL cells. The silencing of LINC00265 expression with LINC00265 siRNA significantly inhibited the malignancy of the ALL cells. RNA pull-down and luciferase assays demonstrated that LINC00265 competitively targeted miR-4500 and enhanced STAT3 expression. Furthermore, miR-4500 inhibitors or overexpressed LINC00265 up-regulated STAT3 expression, and miR-4500 mimics or STAT3 shRNAs eliminated the LINC00265-induced malignancy of the ALL cells.

Conclusion

Mechanistically, LncRNA LINC00265 can competitively interact with miR-4500 and thereby up-regulates STAT3 signaling and enhances the malignancy of tumors.

A Comprehensive Characterization of Monoallelic Expression During Hematopoiesis and Leukemogenesis via Single-Cell RNA-Sequencing

Single-cell RNA-sequencing (scRNA-seq) is becoming a powerful tool to investigate monoallelic expression (MAE) in various developmental and pathological processes. However, our knowledge of MAE during hematopoiesis and leukemogenesis is limited. In this study, we conducted a systematic interrogation of MAEs in bone marrow mononuclear cells (BMMCs) at single-cell resolution to construct a MAE atlas of BMMCs. We identified 1,020 constitutive MAEs in BMMCs, which included imprinted genes such as MEG8, NAP1L5, and IRAIN. We classified the BMMCs into six cell types and identified 74 cell type specific MAEs including MTSS1, MOB1A, and TCF12. We further identified 114 random MAEs (rMAEs) at single-cell level, with 78.1% single-allele rMAE and 21.9% biallelic mosaic rMAE. Many MAEs identified in BMMCs have not been reported and are potentially hematopoietic specific, supporting MAEs are functional relevance. Comparison of BMMC samples from a leukemia patient with multiple clinical stages showed the fractions of constitutive MAE were correlated with fractions of leukemia cells in BMMCs. Further separation of the BMMCs into leukemia cells and normal cells showed that leukemia cells have much higher constitutive MAE and rMAEs than normal cells. We identified the leukemia cell-specific MAEs and relapsed leukemia cell-specific MAEs, which were enriched in immune-related functions. These results indicate MAE is prevalent and is an important gene regulation mechanism during hematopoiesis and leukemogenesis. As the first systematical interrogation of constitutive MAEs, cell type specific MAEs, and rMAEs during hematopoiesis and leukemogenesis, the study significantly increased our knowledge about the features and functions of MAEs.

Increased Plasma Levels of lncRNAs LINC01268, GAS5 and MALAT1 Correlate with Negative Prognostic Factors in Myelofibrosis

Simple Summary

Myelofibrosis (MF) displays the worst prognosis among Philadelphia-negative chronic myeloproliferative neoplasms. There is no curative therapy for MF, except for bone marrow transplantation, which however has a consistent percentage of failure. There is thus an urgent need of novel biomarkers to complement current stratification models and to enable better management of patients. To address this issue, we herein measured the plasma levels of several long noncoding RNAs (lncRNAs). Circulating lncRNAs has been already largely described as potential non-invasive biomarkers in cancers. In our study we unveiled that LINC01268, MALAT1 (both p < 0.0001) and GAS5 (p = 0.0003) plasma levels are significantly higher in MF patients if compared with healthy donors, and their increased plasma levels correlate with several detrimental features in MF. Among them, LINC01268 is an independent variable for both OS (p = 0.0297) and LFS (p = 0.0479), thus representing a putative new biomarker suitable for integrate contemporary prognostic models.

Abstract

Long non-coding RNAs (lncRNAs) have been recently described as key mediators in the development of hematological malignancies. In the last years, circulating lncRNAs have been proposed as a new class of non-invasive biomarkers for cancer diagnosis and prognosis and to predict treatment response. The present study is aimed to investigate the potential of circulating lncRNAs as non-invasive prognostic biomarkers in myelofibrosis (MF), the most severe among Philadelphia-negative myeloproliferative neoplasms. We detected increased levels of seven circulating lncRNAs in plasma samples of MF patients (n = 143), compared to healthy controls (n = 65). Among these, high levels of LINC01268, MALAT1 or GAS5 correlate with detrimental clinical variables, such as high count of leukocytes and CD34+ cells, severe grade of bone marrow fibrosis and presence of splenomegaly. Strikingly, high plasma levels of LINC01268 (p = 0.0018), GAS5 (p = 0.0008) or MALAT1 (p = 0.0348) are also associated with a poor overall-survival while high levels of LINC01268 correlate with a shorter leukemia-free-survival. Finally, multivariate analysis demonstrated that the plasma level of LINC01268 is an independent prognostic variable, suggesting that, if confirmed in future in an independent patients’ cohort, it could be used for further studies to design an updated classification model for MF patients.

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.

Four Prognosis-Associated lncRNAs Serve as Biomarkers in Ovarian Cancer

Long non-coding RNAs (lncRNAs) play crucial roles in ovarian cancer (OC) development. However, prognosis-associated lncRNAs (PALs) for OC have not been completely elucidated. Our study aimed to identify the PAL signature of OC. A total of 663 differentially expressed lncRNAs were identified in the databases. According to the weighted gene coexpression analysis, the highly correlated genes were clustered into seven modules related to the clinical phenotype of OC. A total of 25 lncRNAs that were significantly related to overall survival were screened based on univariate Cox regression analysis. The prognostic risk model constructed contained seven PALs based on the parameter λ_min, which could stratify OC patients into two risk groups. The results showed that the risk groups had different overall survival rates in both The Cancer Genome Atlas (TCGA) and two verified Gene Expression Omnibus (GEO) databases. Univariate and multivariate Cox regression analyses confirmed that the risk model was an independent risk factor for OC. Gene enrichment analysis revealed that the identified genes were involved in some pathways of malignancy. The competitive endogenous RNA (ceRNA) network included five PALs, of which four were selected for cell function assays. The four PALs were downregulated in 33 collected OC tissues and 3 OC cell lines relative to the control. They were shown to regulate the proliferative, migratory, and invasive potential of OC cells via Cell Counting Kit-8 (CCK-8) and transwell assays. Our study fills the gaps of the four PALs in OC, which are worthy of further study.

LncRNAs serve as novel biomarkers for diagnosis and prognosis of childhood ALL

Background

Although some studies have demonstrated that lncRNAs are dysregulated in hematopoietic malignancies and may regulate the progression of leukemia, the detailed mechanism underlying tumorigenesis is still unclear. This study aimed to investigate lncRNAs that are differentially expressed in childhood B-cell acute lymphoblastic leukemia (B-ALL) and T-cell acute lymphoblastic leukemia (T-ALL) and their potential roles in the progression of childhood ALL.

Methods

Microarrays were used to detect differentially expressed lncRNAs and mRNAs. Several aberrantly expressed lncRNAs were validated by qRT-PCR. Leukemia-free survival was analyzed using the Kaplan–Meier method with a log-rank test. The co-expression correlations of lncRNAs and mRNAs were determined by Spearman’s correlation coefficient. CCK-8 assays and flow cytometry were performed to measure cell proliferation and apoptosis.

Results

We revealed that many lncRNAs were abnormally expressed in B-ALL and T-ALL. LncRNA/mRNA co-expression and the gene locus network showed that dysregulated lncRNAs are involved in diverse cellular processes. We also assessed the diagnostic value of the differentially expressed lncRNAs and confirmed the optimal combination of TCONS_00026679, uc002ubt.1, ENST00000411904, and ENST00000547644 with an area under the curve of 0.9686 [95 % CI: 0.9369–1.000, P < 0.001], with 90.7 % sensitivity and 92.19 % specificity, at a cut-off point of -0.5700 to distinguish childhood B-ALL patients from T-ALL patients, implying that these specific lncRNAs may have potential to detect subsets of childhood ALL. Notably, we found that the 8-year leukemia-free survival of patients with high TCONS_00026679 (p = 0.0081), ENST00000522339 (p = 0.0484), ENST00000499583 (p = 0.0381), ENST00000457217 (p = 0.0464), and ENST00000451368 (p = 0.0298) expression levels was significantly higher than that of patients with low expression levels of these lncRNAs, while patients with high uc002ubt.1 (p = 0.0499) and ENST00000547644 (p = 0.0451) expression levels exhibited markedly shorter 8-year leukemia-free survival. In addition, some lncRNAs were found to play different roles in cell proliferation and apoptosis in T-ALL and B-ALL.

Conclusions

Dysregulated lncRNAs involved in different regulatory mechanisms underlying the progression of childhood T-ALL and B-ALL might serve as novel biomarkers to distinguish ALL subsets and indicate poor outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-021-00303-x.

Investigation of lncRNA-mRNA co-expression network in ETV6-RUNX1-positive pediatric B-cell acute lymphoblastic leukemia

ETV6/RUNX1 gene fusion is the most common chromosomal translocation abnormality occurred in pediatric B-cell acute lymphoblastic leukemia (B-ALL). Compared with ETV6-RUNX1-negative patients, ETV6-RUNX1-positive patients possess more improved treatment strategies but higher risk to relapse. In this research, the potential gene interaction networks were constructed intending for elucidating the pathogenesis of B-ALL. We performed the weighted gene co-expression network analysis (WGCNA) to assess the involvement of lncRNA-mRNA pairs in B-ALL patients consisting of 24 ETV6-RUNX1-positive patients and 18 ETV6-RUNX1-negative patients and found a module that was significantly associated with positive/negative trait. Gene Ontology analysis showed that mRNAs in this module were enriched in the positive regulation of MAPK cascade, positive regulation of JNK cascade, and myeloid cell differentiation pathway. To further investigate the relationship between lncRNAs and mRNAs in this significant module, we constructed the lncRNA-mRNA co-expression network. 3 lncRNAs (RP11-170J3.2, RP11-135F9.1 and RP1-151B14.9) were found at the core of the lncRNA-mRNA co-expression network, which had the most co-expression connections with mRNAs. And several related mRNAs (ACTN1, TNFRSF21 and NLRP3) had a significant correlation with the patient survival prediction. Our findings may explicate the pathogenesis of B-ALL, and the disease-associated genes could provide clues to find novel biomarkers for prognosis.

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.

The Role of cis- and trans-Acting RNA Regulatory Elements in Leukemia

RNA molecules are a source of phenotypic diversity and an operating system that connects multiple genetic and metabolic processes in the cell. A dysregulated RNA network is a common feature of cancer. Aberrant expression of long non-coding RNA (lncRNA), micro RNA (miRNA), and circular RNA (circRNA) in tumors compared to their normal counterparts, as well as the recurrent mutations in functional regulatory cis-acting RNA motifs have emerged as biomarkers of disease development and progression, opening avenues for the design of novel therapeutic approaches. This review looks at the progress, challenges and future prospects of targeting cis-acting and trans-acting RNA elements for leukemia diagnosis and treatment.

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.

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.