Noncoding RNA-related polymorphisms in pediatric acute lymphoblastic leukemia susceptibility

PI3K/AKT pathway-related microRNA variants in childhood acute lymphoblastic leukemia

BACKGROUND

Dysregulation of microRNAs (miRNAs) targeting genes in the PI3K/Akt pathway has been implicated in the pathogenesis of childhood acute lymphoblastic leukemia (ALL). However, the impact of genetic variants in these miRNAs on ALL susceptibility has not been extensively explored in the Chinese population.

METHODS

To address this gap, we conducted a case-control study to evaluate the association between genetic variants in five PI3K/AKT pathway-related miRNAs (miR-149, miR-126, miR-492, miR-612, and miR-423) and childhood ALL susceptibility in the Chinese population. Additionally, we investigated the effects of the rs2292832 mutation on ALL cell proliferation and apoptosis.

RESULTS

Our analyses revealed that the miR-149 rs2292832 mutant heterozygous CT genotype was more frequent in the control group than in the ALL cases, indicating a protective effect against ALL (adjusted odds ratio [OR] = 0.78, 95% confidence interval [CI] = 0.63-0.97, p = .024). Stratification analyses further revealed that the miR-149 rs2292832 CC genotype was associated with an increased risk of childhood ALL in subgroups of older children, females, those with parents who never smoked or drank alcohol, those living in painted houses, those with B-ALL, and those with high-risk ALL. Finally, we observed that the rs2292832 mutation inhibited ALL cell proliferation and induced apoptosis (p = .001), providing a potential mechanism by which this genetic variant may influence ALL susceptibility.

CONCLUSION

Our study highlights the significant association between the miR-149 rs2292832 genetic variant and childhood ALL susceptibility in the Chinese population. These findings expand our understanding of the complex genetic landscape underlying ALL and have implications for the development of personalized therapeutic strategies.

Disruption of the Mammalian Ccr4-Not Complex Contributes to Transcription-Mediated Genome Instability

The mammalian Ccr4-Not complex, carbon catabolite repression 4 (Ccr4)-negative on TATA-less (Not), is a large, highly conserved, multifunctional assembly of proteins that acts at different cellular levels to regulate gene expression. It is involved in the control of the cell cycle, chromatin modification, activation and inhibition of transcription initiation, control of transcription elongation, RNA export, and nuclear RNA surveillance; the Ccr4-Not complex also plays a central role in the regulation of mRNA decay. Growing evidence suggests that gene transcription has a vital role in shaping the landscape of genome replication and is also a potent source of replication stress and genome instability. Here, we have examined the effects of the inactivation of the Ccr4-Not complex, via the depletion of the scaffold subunit CNOT1, on DNA replication and genome integrity in mammalian cells. In CNOT1-depleted cells, the elevated expression of the general transcription factor TATA-box binding protein (TBP) leads to increased RNA synthesis, which, together with R-loop accumulation, results in replication fork slowing, DNA damage, and senescence. Furthermore, we have shown that the stability of TBP mRNA increases in the absence of CNOT1, which may explain its elevated protein expression in CNOT1-depleted cells. Finally, we have shown the activation of mitogen-activated protein kinase signalling as evidenced by ERK1/2 phosphorylation in the absence of CNOT1, which may be responsible for the observed cell cycle arrest at the border of G1/S.

MiRNAs in Hematopoiesis and Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common kind of pediatric cancer. Although the cure rates in ALL have significantly increased in developed countries, still 15–20% of patients relapse, with even higher rates in developing countries. The role of non-coding RNA genes as microRNAs (miRNAs) has gained interest from researchers in regard to improving our knowledge of the molecular mechanisms underlying ALL development, as well as identifying biomarkers with clinical relevance. Despite the wide heterogeneity reveled in miRNA studies in ALL, consistent findings give us confidence that miRNAs could be useful to discriminate between leukemia linages, immunophenotypes, molecular groups, high-risk-for-relapse groups, and poor/good responders to chemotherapy. For instance, miR-125b has been associated with prognosis and chemoresistance in ALL, miR-21 has an oncogenic role in lymphoid malignancies, and the miR-181 family can act either as a oncomiR or tumor suppressor in several hematological malignancies. However, few of these studies have explored the molecular interplay between miRNAs and their targeted genes. This review aims to state the different ways in which miRNAs could be involved in ALL and their clinical implications.

Influence of Genetic Variations in miRNA and Genes Encoding Proteins in the miRNA Synthesis Complex on Toxicity of the Treatment of Pediatric B-Cell ALL in the Brazilian Amazon

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer in the world. Single nucleotide variants (SNVs) in miRNA and genes encoding proteins of the miRNA synthesis complex (SC) may affect the processing of drugs used in the treatment of ALL, resulting in treatment-related toxicities (TRTs). We investigated the role of 25 SNVs in microRNA genes and genes encoding proteins of the miRNA SC, in 77 patients treated for ALL-B from the Brazilian Amazon. The 25 SNVs were investigated using the TaqMan^® OpenArray™ Genotyping System. SNVs rs2292832 (MIR149), rs2043556 (MIR605), and rs10505168 (MIR2053) were associated with an increased risk of developing Neurological Toxicity, while rs2505901 (MIR938) was associated with protection from this toxicity. MIR2053 (rs10505168) and MIR323B (rs56103835) were associated with protection from gastrointestinal toxicity, while DROSHA (rs639174) increased the risk of development. The rs2043556 (MIR605) variant was related to protection from infectious toxicity. SNVs rs12904 (MIR200C), rs3746444 (MIR499A), and rs10739971 (MIRLET7A1) were associated with a lower risk for severe hematologic toxicity during ALL treatment. These findings reveal the potential for the use of these genetic variants to understand the development of toxicities related to the treatment of ALL in patients from the Brazilian Amazon region.

The association between microRNA polymorphisms and the risk of childhood acute lymphoblastic leukemia: A meta-analysis

The aim of this meta-analysis was to determine the relationship between microRNA polymorphisms and the risk of childhood acute lymphoblastic leukemia comprehensively. PubMed, EMBASE, Scopus, Web of Science, the Cochrane Library, Global Index Medicus, Clinicaltrials.gov, ProQuest, and Open Grey databases were used to find relevant papers. Using the STATA 16.0 and CMA 3.0 software, the significance of relationships between microRNA polymorphisms and childhood acute lymphoblastic leukemia risk was evaluated using odds ratios (ORs) and 95 % confidence intervals (95 % CIs) for five genetic models. The results of the meta-analysis showed that there was no significant association between the polymorphism of miR-146a rs2910164 and childhood acute lymphoblastic leukemia risk in different genetic models. Also, in the sensitivity analysis, removing Xue's study from the analysis indicated that both the homozygote and recessive models are significantly affected. Additionally, there was a statistically significant relationship between the polymorphisms of pri-miR-34b/c rs4938723 (in the homozygote and recessive models) and miR-612 rs12803915 (in the allele and dominant models) and childhood acute lymphoblastic leukemia risk. These findings suggest that the rs4938723 and rs12803915 polymorphisms may have a role in the development of childhood acute lymphoblastic leukemia.

Relationship between miRNAs polymorphisms and peripheral blood leukocyte DNA telomere length in coke oven workers: A cross-sectional study

OBJECTIVE

The purpose of this study was to investigate the factors affecting telomere length (TL) in coke oven workers by analyzing the interaction between miRNAs polymorphisms and coke oven emissions (COEs) exposure.

METHODS

A total of 544 coke oven workers and 238 healthy controls were recruited. Peripheral blood was collected from the subjects, genomic DNA was extracted, leukocyte TL was detected by real-time quantitative polymerase chain reaction, and fifteen polymorphisms of eight miRNAs were genotyped by flight mass spectrometry.

RESULTS

Statistical analysis showed that the peripheral blood DNA TL in the exposure group was shorter than that in the control group (P < 0.001). Generalized linear model found that COEs-exposure [β (95%CI) = -0.427 (-0.556, -0.299), P < 0.001], genotype CC+CT for miR-612 rs1144925 [β (95%CI) = -0.367 (-0.630, -0.104), P = 0.006], and the interaction of miR-181B1 rs12039395 TT genotype and COEs-exposure [β (95% CI) = 0.564 (0.108, 1.020), P = 0.015] were associated with the shortened TL.

CONCLUSION

COEs-exposure and miR-612 rs1144925 TT could promote telomere shortening in coke oven workers. The interaction of miR-181B1 rs12039395 TT genotype and COEs-exposure could protect telomere. This provides clues for further mechanistic studies between miRNA and telomere damage.

Association Between MIR3117 and MIR612 Genes Polymorphisms with Childhood Acute Lymphoblastic Leukemia in the Mexican Population

INTRODUCTION

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer in the world, which is associated with a wide spectrum of factors that play an important role in epidemiology, risk stratification, and therapeutic intervention. Several studies have shown the role of microRNAs (miRNAs) in the development of the disease. Genetic variations such as single-nucleotide polymorphisms (SNPs) in miRNAs can alter their function and lead to alter the expression of their target genes.

OBJECTIVE

The aim of this study was to evaluate the association of rs12402181 in MIR3117 and rs12803915 in MIR612 with the risk of childhood preB-ALL in Mexican population.

MATERIAL AND METHODS

DNA from 148 children (<18 years old) diagnosed with preB-ALL and 172 samples from participants in control group were included in the present study. Genotyping of the rs12402181 and rs12803915 polymorphisms was carried out by Real-Time PCR. To estimate the risk factor, the multiple genetic models co-dominant, dominant, and recessive were determined in both polymorphisms.

RESULTS

In dominant genetic model from rs12402181, a high risk of susceptibility to ALL was observed (OR = 2.03, 95% CI = 1.27-3.22, p = 0.003). In the analysis adjusted for gender, a significant increase in the risk of ALL was maintained (OR = 2.03, 95% CI = 1.28-3.24, p = 0.003). The rs12803915 polymorphism was no associated with the risk of susceptibility to preB-ALL in any of the genetic models using in this study.

CONCLUSIONS

Our data indicated that the A allele of the rs12402181 polymorphism may be considered as a genetic biomarker of preB-ALL susceptibility. Likewise, it was identified that the A allele of the rs12402181 polymorphism is an independent risk factor for ALL.

MicroRNAs and the Diagnosis of Childhood Acute Lymphoblastic Leukemia: Systematic Review, Meta-Analysis and Re-Analysis with Novel Small RNA-Seq Tools

Simple Summary

MicroRNAs (miRNAs) have been under the spotlight for the last three decades. These non-coding RNAs seem to be dynamic regulators of mRNA stability and translation, in addition to interfering with transcription. Circulating miRNAs play a critical role in cell-to-cell interplay; therefore, they can serve as disease biomarkers. Meta-analysis of published data revealed that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against acute lymphoblastic leukemia (ALL) in children. Reanalysis of small RNA-seq data with novel tools identified significantly overexpressed members of the miR-128, miR-181, miR-130 and miR-17 families and significantly lower expression of miR-30, miR-24-2 and miR143~145 clusters, miR-574 and miR-618 in pediatric T-ALL cases compared with controls. Inconsistencies in methodology and study designs in most published material preclude reproducibility, and further cohort studies need to be conducted in order to empower novel tools, such as ALLSorts and RNAseqCNV.

Abstract

MicroRNAs (miRNAs) have been implicated in childhood acute lymphoblastic leukemia (ALL) pathogenesis. We performed a systematic review and meta-analysis of miRNA single-nucleotide polymorphisms (SNPs) in childhood ALL compared with healthy children, which revealed (i) that the CC genotype of rs4938723 in pri-miR-34b/c and the TT genotype of rs543412 in miR-100 confer protection against ALL occurrence in children; (ii) no significant association between rs2910164 genotypes in miR-146a and childhood ALL; and (iii) SNPs in DROSHA, miR-449b, miR-938, miR-3117 and miR-3689d-2 genes seem to be associated with susceptibility to B-ALL in childhood. A review of published literature on differential expression of miRNAs in children with ALL compared with controls revealed a significant upregulation of the miR-128 family, miR-130b, miR-155, miR-181 family, miR-210, miR-222, miR-363 and miR-708, along with significant downregulation of miR-143 and miR-148a, seem to have a definite role in childhood ALL development. MicroRNA signatures among childhood ALL subtypes, along with differential miRNA expression patterns between B-ALL and T-ALL cases, were scrutinized. With respect to T-ALL pediatric cases, we reanalyzed RNA-seq datasets with a robust and sensitive pipeline and confirmed the significant differential expression of hsa-miR-16-5p, hsa-miR-19b-3p, hsa-miR-92a-2-5p, hsa-miR-128-3p (ranked first), hsa-miR-130b-3p and -5p, hsa-miR-181a-5p, -2-3p and -3p, hsa-miR-181b-5p and -3p, hsa-miR-145-5p and hsa-miR-574-3p, as described in the literature, along with novel identified miRNAs.

miR-146a, miR-196a2, miR-499, and miR-149 linked with susceptibility to acute lymphoblastic leukemia: A case-control study in Tunisia

BACKGROUND

MicroRNAs (miRNAs) are promising biomarkers of hematological malignancies, including acute lymphoblastic leukaemia (ALL). Recent studies revealed that miRNA single nucleotide polymorphisms (miR-SNP) modulate cancer risk by regulating various signaling pathways. However, their association with altered risk of ALL yielded inconsistent results.

OBJECTIVE

This study aims to investigate the association of four miR-SNPs with altered risk of ALL risk in Tunisian, the first on North African population.

METHODS

A retrospective case-control study exploring the association of miR-146a, miR-196a2, miR-499, and miR-149 SNPs in 126 ALL patients and 126 healthy controls.

RESULTS

Of the tested variants, significantly lower minor allele frequencies (MAF) of miR-146a C-allele and higher MAF frequency of miR-149 T-allele (P = 0.006) were seen in ALL cases. The association of miR-149 rs2292832 (Pc = 0.02), but not miR-146a rs2910164 (Pc = 0.11) persisted after correcting for multiple comparisons. Significantly reduced prevalence of miR-146a G/C genotype and higher frequency of miR-149 C/T genotype were seen in ALL cases vs. control subjects, which translated into negative association of miR-146a (rs2910164) with ALL according to the codominant and dominant models. Similarly, miR-149 (rs2292832) was positively associated with ALL according to the codominant and dominant genetic models. Three combinations comprising miR-146a/miR-196a2 GG vs CT + TT genotype combination, miR-146a/miR-499 GG vs TC + CC genotype combination, and miR-146a/miR-149 GG vs CT + TT genotype combination, were less frequent in ALL patients than in controls, and were negatively associated with the presence of ALL.

CONCLUSION

Our study suggests that miR-146a and miR-149 polymorphisms constitute biomarkers for personalized diagnosis of ALL.

Integrated Deadenylase Genetic Association Network and Transcriptome Analysis in Thoracic Carcinomas

The poly(A) tail at the 3′ end of mRNAs determines their stability, translational efficiency, and fate. The shortening of the poly(A) tail, and its efficient removal, triggers the degradation of mRNAs, thus, regulating gene expression. The process is catalyzed by a family of enzymes, known as deadenylases. As the dysregulation of gene expression is a hallmark of cancer, understanding the role of deadenylases has gained additional interest. Herein, the genetic association network shows that CNOT6 and CNOT7 are the most prevalent and most interconnected nodes in the equilibrated diagram. Subsequent silencing and transcriptomic analysis identifies transcripts possibly regulated by specific deadenylases. Furthermore, several gene ontologies are enriched by common deregulated genes. Given the potential concerted action and overlapping functions of deadenylases, we examined the effect of silencing a deadenylase on the remaining ones. Our results suggest that specific deadenylases target unique subsets of mRNAs, whilst at the same time, multiple deadenylases may affect the same mRNAs with overlapping functions.

Genetic Variants of MicroRNA and DROSHA Genes in Association With the Risk of Tuberculosis in the Amazon Population

Tuberculosis (TB) is a chronic infection caused by Mycobacterium tuberculosis (Mtb) with high incidence and mortality. Studies reported that host genetic variants might be associated with the risk of tuberculosis. The aim of this study was to perform an association study between 26 single nucleotide polymorphisms (SNPs) and tuberculosis and evaluate whether these SNPs may confer risk factors to tuberculosis in the Amazon population. There were 52 males and 126 females, with total of 178 healthy controls. Genotyping was performed using TaqMan Open Array Genotyping. Ancestry-informative markers were used to estimate the ancestral proportions of the individuals in the case and control groups. The results indicated that the SNPs rs10035440 (DROSHA), rs7372209 (miR26-a1), rs1834306 (miR100), rs4919510 (miR608), and rs10739971 (pri-let-7a-1) were significantly associated with high risk and rs3746444 (miR499) and rs6505162 (miR423), with low risk of developing tuberculosis in the Amazon population. Our study concluded that seven miRNA polymorphisms were associated with tuberculosis. Our study contributes to a better understanding of TB pathogenesis and may promote the development of new diagnostic tools against M. tuberculosis infection.

CNOT6: A Novel Regulator of DNA Mismatch Repair

DNA mismatch repair (MMR) is a highly conserved pathway that corrects both base–base mispairs and insertion-deletion loops (IDLs) generated during DNA replication. Defects in MMR have been linked to carcinogenesis and drug resistance. However, the regulation of MMR is poorly understood. Interestingly, CNOT6 is one of four deadenylase subunits in the conserved CCR4-NOT complex and it targets poly(A) tails of mRNAs for degradation. CNOT6 is overexpressed in acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) and androgen-independent prostate cancer cells, which suggests that an altered expression of CNOT6 may play a role in tumorigenesis. Here, we report that a depletion of CNOT6 sensitizes human U2OS cells to N-methyl-N′nitro-N-nitrosoguanidine (MNNG) and leads to enhanced apoptosis. We also demonstrate that the depletion of CNOT6 upregulates MMR and decreases the mutation frequency in MMR-proficient cells. Furthermore, the depletion of CNOT6 increases the stability of mRNA transcripts from MMR genes, leading to the increased expression of MMR proteins. Our work provides insight into a novel CNOT6-dependent mechanism for regulating MMR.

Differential expression of miRNA in histological subtype of Wilms tumor

INTRODUCTION

Wilms tumor is the most common renal malignancy in children and difficult to differentiate from other paediatric abdominal tumors radiologically, necessitating an invasive procedure for diagnosis. Previous studies have shown the potential role of miRNA as biomarkers for diagnosis, histological subtyping and prognosis. In this study, we are exploring the role of miRNA in the histological subtyping of Wilms tumor in the Indian population.

MATERIALS AND METHODS

A total of 15 cases of Wilms tumor were evaluated for global miRNA expression analysis by microarray. Total RNA was extracted from fresh frozen tumor and miRNA expression analysis was performed using Agilent platform. Unsupervised clustering was done to analyse the data.

RESULTS

Using unpaired student T test, top 10 significantly differentially expressed miRNA were selected which could differentiate among different histological subtypes by unsupervised hierarchical clustering and principal component analysis. The presence of necrosis, heterologous differentiation led to change in miRNA expression profile and led to a distinct cluster formation.

CONCLUSIONS

A panel of 5 miRNAs (miR1, 133b, 299-3p, 499a-5p, 491-3p) could differentiate among different histological subtypes of Wilms tumor, thus avoiding an invasive procedure in children, however, further confirmation using real time PCR analysis will be needed.

Association Analysis Between the Functional Single Nucleotide Variants in miR-146a, miR-196a-2, miR-499a, and miR-612 With Acute Lymphoblastic Leukemia

Background

Acute lymphoblastic leukemia (ALL) is characterized by an abnormal proliferation of immature lymphocytes, in whose development involves both environmental and genetic factors. It is well known that single nucleotide polymorphisms (SNPs) in coding and noncoding genes contribute to the susceptibility to ALL. This study aims to determine whether SNPs in miR-146a, miR-196a-2, miR-499a, and miR-612 genes are associated with the risk to ALL in pediatric Mexican population.

Methods

A multicenter case-control study was carried out including patients with de novo diagnosis of ALL and healthy subjects as control group. The DNA samples were obtained from saliva and peripheral blood, and the genotyping of rs2910164, rs12803915, rs11614913, and rs3746444 was performed using the 5′exonuclease technique. Gene-gene interaction was evaluated by the multifactor dimensionality reduction (MDR) software.

Results

miR-499a rs3746444 showed significant differences among cases and controls. The rs3746444G allele was found as a risk factor to ALL (OR, 1.6 [95% CI, 1.05–2.5]; p = 0.028). The homozygous GG genotype of rs3746444 confers higher risk to ALL than the AA genotype (OR, 5.3 [95% CI, 1.23–23.4]; p = 0.01). Moreover, GG genotype highly increases the risk to ALL in male group (OR, 17.6 [95% CI, 1.04–298.9]; p = 0.00393). In addition, an association in a gender-dependent manner among SNPs located in miR-146a and miR-196a-2 genes and ALL susceptibility was found.

Conclusion

Our findings suggest that SNP located in miR-499a, miR-146a, and miR-196a-2 genes confer risk to ALL in Mexican children. Experimental analysis to decipher the role of these SNPs in human hematopoiesis could improve our understanding of the molecular mechanism underlying the development of ALL.

Argonaute Proteins Take Center Stage in Cancers

Simple Summary

The dysregulation of RNA interference (RNAi) has often been observed in cancers, where the main focus of research has been on the small RNA molecules directing RNAi. In this review, we focus on the activity of Argonaute proteins, central components of RNAi, in tumorigenesis, and also highlight their potential applications in grading tumors and anti-cancer therapies.

Abstract

Argonaute proteins (AGOs) play crucial roles in RNA-induced silencing complex (RISC) formation and activity. AGOs loaded with small RNA molecules (miRNA or siRNA) either catalyze endoribonucleolytic cleavage of target RNAs or recruit factors responsible for translational silencing and target destabilization. miRNAs are well characterized and broadly studied in tumorigenesis; nevertheless, the functions of the AGOs in cancers have lagged behind. Here, we discuss the current state of knowledge on the role of AGOs in tumorigenesis, highlighting canonical and non-canonical functions of AGOs in cancer cells, as well as the biomarker potential of AGO expression in different of tumor types. Furthermore, we point to the possible application of the AGOs in development of novel therapeutic approaches.

Evaluation of the clinical significance of RNase III enzyme DROSHA in pediatrics acute lymphocytic leukemia

Acute lymphocytic leukemia (ALL) is one of the subtypes of leukemia; it is one of the leading causes of malignancy and morbidity and childhood mortality. This study examined the dysregulation of DROSHA and its clinical implications in ALL. In the case-control investigation, we have included 140 samples, consisting of 70 peripheral whole blood samples diagnosed with ALL and 70 age and sex-matched healthy children, to assess the level of expression of DROSHA mRNA between two groups. Quantitative Real-Time PCR was used to establish the level of DROSHA gene expression in the patients and controls. The results revealed that DROSHA was overexpressed in patients compared with controls (p < 0.001). There were no major differences between DROSHA expression and demographic factors and clinicopathological parameters (p > 0.001). The finding of the study revealed that DROSHA expression in ALL patients is significantly up-regulated; which is suggesting that may be served as a critical role in the pathogenesis of ALL. Also, DROSHA will possibly be utilized as a novel therapeutic target for ALL patients within the future.

High Resolution Melting Analysis for Evaluation of mir-612 (Rs12803915) Genetic Variant with Susceptibility to Pediatric Acute Lymphoblastic Leukemia

Background

Acute lymphoblastic leukemia (ALL) is a highly heterogeneous malignancy that accounts for nearly 75% of leukemias in children. While the exact mechanism of ALL is not fully understood, some genetic variants have been implicated as associated with ALL susceptibility. The association between some genetic variants in miRNA genes and ALL risk has been described previously. A previous study suggested that mir-612 rs12803915 G> A may be associated with pediatric ALL risk. High-resolution melting (HRM) analysis is a reliable method that can be applied for polymorphism detection.

Methods

This retrospective study was performed on 100 B-ALL patients (52 males and 48 females; age 4.6 ± 3.2 years) and 105 age- and sex-matched healthy controls (48 males and 57 females; age 5.1 ± 3 years). We used HRM to identify mir-612 rs12803915 genotypes. Sanger sequencing was applied to validate the HRM results.

Results

High resolution melting analysis was used to genotype the mir-612 rs12803915 polymorphism. We found no association between rs12803915 allele A and B-ALL risk in any inheritance models (p> 0.05).

Conclusion

HRM is a suitable method to detect SNP rs12803915 in the mir-612 gene; however, we found no significant association between the rs12803915 polymorphism and ALL risk.

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.

The Regulatory Properties of the Ccr4-Not Complex

The mammalian Ccr4–Not complex, carbon catabolite repression 4 (Ccr4)-negative on TATA-less (Not), is a large, highly conserved, multifunctional assembly of proteins that acts at different cellular levels to regulate gene expression. In the nucleus, it is involved in the regulation of the cell cycle, chromatin modification, activation and inhibition of transcription initiation, control of transcription elongation, RNA export, nuclear RNA surveillance, and DNA damage repair. In the cytoplasm, the Ccr4–Not complex plays a central role in mRNA decay and affects protein quality control. Most of our original knowledge of the Ccr4–Not complex is derived, primarily, from studies in yeast. More recent studies have shown that the mammalian complex has a comparable structure and similar properties. In this review, we summarize the evidence for the multiple roles of both the yeast and mammalian Ccr4–Not complexes, highlighting their similarities.

Association between genetic variants in DICER1 and cancer risk: An updated meta-analysis

Dysfunctions in mechanisms of gene regulation based on RNA interference are recognized as a common feature of the molecular basis of cancer pathogenesis. Therefore, as one of the crucial components of the machinery involved in the biogenesis of both siRNAs and microRNA molecules, DICER was recognized as one of the candidates for the research in the field of carcinogenesis. Due to their potential functional properties, several genetic variants located within DICER1 gene were analyzed for their possible association with the susceptibility to cancer through case-control studies. In order to elucidate their effect on the overall cancer risk, we conducted an updated meta-analysis of all eligible association studies. The publications were selected based on PubMed database search, while OpenMeta-analyst and MetaGenyo software were used for quantitative data synthesis. Statistically significant results were found for the association of rs1057035 with the overall cancer risk under multiple genetic models (P_{CT vs. TT} < 0.001, OR_{CT vs. TT} = 0.870, 95% CI = 0.812-0.933; P_allelic = 0.009, OR_allelic = 0.896, 95% CI = 0.825-0.973; P_dom < 0.001, OR_dom = 0.874, 95% CI = 0.817-0.934; P_overdom = 0.004, OR_overdom = 0.858, 95% CI = 0.773-0.953). Other selected genetic variants within DICER1, rs13078, rs1209904 and rs3742330, did not show the association with the overall susceptibility to malignant diseases. We conclude that rs1057035 may represent a potential biomarker associated with the risk of developing cancer, which requires a confirmation in a larger set of studies.

LncRNA HOTAIR enhances breast cancer radioresistance through facilitating HSPA1A expression via sequestering miR-449b-5p

BACKGROUND

Breast cancer (BRCA) is the leading cause of cancer-related death in women worldwide. Pre- and postoperative radiotherapy play a pivotal role in BRCA treatment but its efficacy remains limited and plagued by the emergence of radiation resistance, which aggravates patient prognosis. The long noncoding RNA (lncRNA)-implicated mechanisms underlying radiation resistance are rarely reported. The aim of this study was to determine whether lncRNA HOX transcript antisense RNA (HOTAIR) modulated the radiosensitivity of breast cancer through HSPA1A.

METHODS

A Gammacell 40 Exactor was used for irradiation treatment. Bioinformatic tools and luciferase reporter assay were adopted to explore gene expression profile and demonstrate the interactions between lncRNA, miRNA and target mRNA 3'-untranslated region (3'-UTR). The expression levels of certain genes were determined by real-time PCR and western-blot analyses. in vitro and in vivo functional assays were conducted by cell viability and tumorigenicity assays.

RESULTS

The levels of oncogenic lncRNA HOTAIR were positively correlated with the malignancy of BRCA but reversely correlated with the radiosensitivity of breast cancer cells. Moreover, the expression levels of HOTAIR were positively associated with those of heat shock protein family A (Hsp70) member 1A (HSPA1A) in clinical BRCA tissues and HOTAIR upregulated HSPA1A at the mRNA and protein levels in irradiated BRCA cells. Mechanistically, miR-449b-5p restrained HSPA1A expression through targeting the 3'-UTR of HSPA1A mRNA, whereas HOTAIR acted as a competing sponge to sequester miR-449b-5p and thereby relieved the miR-449b-5p-mediated HSPA1A repression. Functionally, HOTAIR conferred decreased radiosensitivity on BRCA cells, while miR-449b-5p overexpression or HSPA1A knockdown abrogated the HOTAIR-enhanced BRCA growth under the irradiation exposure both in vitro and in vivo.

CONCLUSIONS

LncRNA HOTAIR facilitates the expression of HSPA1A by sequestering miR-449b-5p post-transcriptionally and thereby endows BRCA with radiation resistance.

KEY POINTS

Therapeutically, HOTAIR and HSPA1A may be employed as potential targets for BRCA radiotherapy. Our findings shed new light into the mechanism by which lncRNAs modulate the radiosensitivity of tumors.

Association between genetic variants in genes encoding Argonaute proteins and cancer risk: A meta-analysis

With the accumulation of evidence of the involvement of small-RNA-based regulatory mechanisms in carcinogenesis, genes encoding Ago proteins emerged as candidates for case-control studies on cancer. Since the data from association studies on various cancer types was not previously meta-analyzed, the potential effect of these variants on cancer risk in general was not previously evaluated. Therefore, we conducted a meta-analysis of all eligible studies, testing multiple genetic models of association. The identification of publication was based on PubMed database search, while OpenMeta-analyst, as well as MetaGenyo software, were used for quantitative data synthesis. AGO1 genetic variant rs636832 was found to associate with the overall cancer risk, assuming the overdominant genetic model (P =  0.030; OR_overdom = 0.865, 95%CI 0.759-0.986). For the same genetic variant, statistical significance was reached for the association with solid tumors, as well as with lung cancer susceptibility. Similar results were found in the Asians cohort for another AGO1 variant, rs595961. For rs4961280, none of the meta-analyses yielded statistically significant results. We conclude that genetic variants rs636832 and rs595961 located within AGO1 may represent susceptibility variants for specific types of cancer, while the association with malignant diseases was not determined for AGO2 variant rs4961280.

The Ccr4-Not Complex: Architecture and Structural Insights

The Ccr4-Not complex is an essential multi-subunit protein complex that plays a fundamental role in eukaryotic mRNA metabolism and has a multitude of different roles that impact eukaryotic gene expression . It has a conserved core of three Not proteins, the Ccr4 protein, and two Ccr4 associated factors, Caf1 and Caf40. A fourth Not protein, Not4, is conserved, but is only a stable subunit of the complex in yeast. Certain subunits have been duplicated during evolution, with functional divergence, such as Not3 in yeast, and Ccr4 or Caf1 in human. However the complex includes only one homolog for each protein. In addition, species-specific subunits are part of the complex, such as Caf130 in yeast or Not10 and Not11 in human. Two conserved catalytic functions are associated with the complex, deadenylation and ubiquitination . The complex adopts an L-shaped structure, in which different modules are bound to a large Not1 scaffold protein. In this chapter we will summarize our current knowledge of the architecture of the complex and of the structure of its constituents.

A New Method for Biostatistical miRNA Pattern Recognition with Topological Properties of Visibility Graphs in 3D Space

Visibility is a very important topic in computer graphics and especially in calculations of global illumination. Visibility determination, the process of deciding which surface can be seen from a certain point, has also problematic applications in biomedical engineering. The problem of visibility computation with mathematical tools can be presented as a visibility network. Instead of utilizing a 2D visibility network or graphs whose construction is well known, in this paper, a new method for the construction of 3D visibility graphs will be proposed. Drawing graphs as nodes connected by links in a 3D space is visually compelling but computationally difficult. Thus, the construction of 3D visibility graphs is highly complex and requires professional computers or supercomputers. A new method for optimizing the algorithm visibility network in a 3D space and a new method for quantifying the complexity of a network in DNA pattern recognition in biomedical engineering have been developed. Statistical methods have been used to calculate the topological properties of a visibility graph in pattern recognition. A new n-hyper hybrid method is also used for combining an intelligent neural network system for DNA pattern recognition with the topological properties of visibility networks of a 3D space and for evaluating its prospective use in the prediction of cancer.

A Meta-Analysis of miR-499 rs3746444 Polymorphism for Cancer Risk of Different Systems: Evidence From 65 Case-Control Studies

MicroRNAs (miRNAs) are a class of endogenous, short and non-coding RNAs that may play important roles in the pathogenesis of tumor. The associations between microRNA-499 rs3746444 polymorphism and cancer risk in different systems remain inconclusive. This article is aimed to obtain more exact estimation of these relationships through a meta-analysis based on 52,456 individuals. We retrieved relevant and eligible studies from Pubmed and Embase database up to January 10, 2018. ORs and 95% CIs were used to estimate the associations between miR-499 polymorphism and cancer susceptibility in different systems. All analyses were performed using the Stata 11.0 software. A total of 65 case-control studies were retrieved using explicit inclusion and exclusion criteria. The study included 23,762 cases and 28,694 controls. Overall cancer analysis showed the association between miR-499 polymorphism and susceptibility to cancer was significant. MicroRNA-499 rs3746444 was found to be significantly associated with increased risk of cancer of the respiratory system (CC vs. TT: OR = 1.575, 95% CI = 1.268–1.955, CC vs. TC+TT: OR = 1.527, 95% CI = 1.232–1.892), digestive system (CC vs. TT: OR = 1.153, 95% CI = 1.027–1.295; TC vs. TT: OR = 1.109, 95% CI = 1.046–1.176; CC+TC vs. TT: OR = 1.112, 95% CI = 1.018–1.216; CC vs. TC+TT: OR = 1.137, 95% CI = 1.016–1.272; C vs. T: OR = 1.112, 95% CI = 1.025–1.206), urinary system (TC vs. TT: OR = 1.307, 95% CI = 1.130–1.512; CC+TC vs. TT: OR = 1.259, 95% CI = 1.097–1.446; C vs. T: OR = 1.132, 95% CI = 1.014–1.264), and gynecological system (C vs. T: OR = 1.169, 95% CI = 1.002–1.364). In the subgroup analysis by ethnicity, the result showed that significant association with an increased cancer risk was found in Asian. Subgroup analysis based on type of tumor was also performed, miR-499 rs3746444 is associated with susceptibility of cervical squamous cell carcinoma, lung cancer, prostate cancer, and hepatocellular carcinoma.

Involvement of SNPs in miR-3117 and miR-3689d2 in childhood acute lymphoblastic leukemia risk

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Numerous studies have shown that microRNAs (miRNAs) could play a role in this disease. Nowadays, more than 2500 miRNAs have been described, that regulate more than 50% of genes, including those involved in B-cell maturation, differentiation and proliferation. Genetic variants in miRNAs can alter their own levels or function, affecting their target gene expression, and then, may affect ALL risk. Therefore, the aim of this study was to determine the role of miRNA genetic variants in B-ALL susceptibility. We analyzed all variants in pre-miRNAs (MAF > 1%) in two independent cohorts from Spain and Slovenia and inferred their functional effect by in silico analysis. SNPs rs12402181 in miR-3117 and rs62571442 in miR-3689d2 were associated with ALL risk in both cohorts, possibly through their effect on MAPK signalling pathway. These SNPs could be novel markers for ALL susceptibility.

Identification of genetic variants predictive of early onset pancreatic cancer through a population science analysis of functional genomic datasets

Biomarkers are critically needed for the early detection of pancreatic cancer (PC) are urgently needed. Our purpose was to identify a panel of genetic variants that, combined, can predict increased risk for early-onset PC and thereby identify individuals who should begin screening at an early age. Previously, we identified genes using a functional genomic approach that were aberrantly expressed in early pathways to PC tumorigenesis. We now report the discovery of single nucleotide polymorphisms (SNPs) in these genes associated with early age at diagnosis of PC using a two-phase study design. In silico and bioinformatics tools were used to examine functional relevance of the identified SNPs. Eight SNPs were consistently associated with age at diagnosis in the discovery phase, validation phase and pooled analysis. Further analysis of the joint effects of these 8 SNPs showed that, compared to participants carrying none of these unfavorable genotypes (median age at PC diagnosis 70 years), those carrying 1–2, 3–4, or 5 or more unfavorable genotypes had median ages at diagnosis of 64, 63, and 62 years, respectively (P = 3.0E–04). A gene-dosage effect was observed, with age at diagnosis inversely related to number of unfavorable genotypes (P_trend = 1.0E–04). Using bioinformatics tools, we found that all of the 8 SNPs were predicted to play functional roles in the disruption of transcription factor and/or enhancer binding sites and most of them were expression quantitative trait loci (eQTL) of the target genes. The panel of genetic markers identified may serve as susceptibility markers for earlier PC diagnosis.

Novel Gene and Network Associations Found for Acute Lymphoblastic Leukemia Using Case-Control and Family-Based Studies in Multiethnic Populations

Background: Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, suggesting that germline variants influence ALL risk. Although multiple genome-wide association (GWA) studies have identified variants predisposing children to ALL, it remains unclear whether genetic heterogeneity affects ALL susceptibility and how interactions within and among genes containing ALL-associated variants influence ALL risk.Methods: Here, we jointly analyzed two published datasets of case-control GWA summary statistics along with germline data from ALL case-parent trios. We used the gene-level association method PEGASUS to identify genes with multiple variants associated with ALL. We then used PEGASUS gene scores as input to the network analysis algorithm HotNet2 to characterize the genomic architecture of ALL.Results: Using PEGASUS, we confirmed associations previously observed at genes such as ARID5B, IKZF1, CDKN2A/2B, and PIP4K2A, and we identified novel candidate gene associations. Using HotNet2, we uncovered significant gene subnetworks that may underlie inherited ALL risk: a subnetwork involved in B-cell differentiation containing the ALL-associated gene CEBPE, and a subnetwork of homeobox genes, including MEIS1Conclusions: Gene and network analysis uncovered loci associated with ALL that are missed by GWA studies, such as MEIS1 Furthermore, ALL-associated loci do not appear to interact directly with each other to influence ALL risk, and instead appear to influence leukemogenesis through multiple, complex pathways.Impact: We present a new pipeline for post hoc analysis of association studies that yields new insight into the etiology of ALL and can be applied in future studies to shed light on the genomic underpinnings of cancer. Cancer Epidemiol Biomarkers Prev; 26(10); 1531-9. ©2017 AACR.

Genetic susceptibility in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and a leading cause of death due to disease in children. The genetic basis of ALL susceptibility has been supported by its association with certain congenital disorders and, more recently, by several genome-wide association studies (GWAS). These GWAS identified common variants in ARID5B, IKZF1, CEBPE, CDKN2A, PIP4K2A, LHPP and ELK3 influencing ALL risk. However, the risk variants of these SNPs were not validated in all populations, suggesting that some of the loci could be population specific. On the other hand, the currently identified risk SNPs in these genes only account for 19% of the additive heritable risk. This estimation indicates that additional susceptibility variants could be discovered. In this review, we will provide an overview of the most important findings carried out in genetic susceptibility of childhood ALL in all GWAS and subsequent studies and we will also point to future directions that could be explored in the near future.

Pre-micro RNA-499 Gene Polymorphism rs3746444 T/C is Associated with Susceptibility to Rheumatoid Arthritis in Egyptian Population

Pre-miRNA-499 gene is associated with autoimmune disease. Mir-449 rs3746444 polymorphism is inconsistent for rheumatoid arthritis (RA). This study aimed to investigate association of mir-499 rs3746444 polymorphism with RA activity and severity in Egyptian population. The study population was conducted as case control study in 100 RA patients diagnosed according to the American College of Rheumatology classification criteria for RA, and the control group included 100 healthy subjects who were age-and sex-matched to the RA group. Different genotypes were assessed using polymerase chain reaction-restriction fragment length polymorphism. 95% Confidence interval and odds ratio were defined to assess the strength of association. Regarding patients, thirty-three patients carried TT genotype, fifty-three patients carried TC genotype and fourteen patients carried CC genotype. So the frequency of the minor C allele in RA patients was significantly higher than the control subjects (P = 0.037). TC, CC genotypes and C allele frequencies were significantly associated with disease severity as they had high rheumatoid factor (55.78 µIU/ml) and anti-cyclic citrullinated peptide (Anti-CCP) antibody (297.32 µIU/ml). Moreover, the heterozygote TC had more severe and more active form of the disease compared with homozygote CC or TT as they had high Anti-CCP antibody, and disease activity score 28 (score 5). Our work suggests that C allele of Pre-miRNA rs3746444 polymorphism contributes to heritability of susceptibility to RA compared to T allele. This polymorphism was associated with the activity and severity of the disease.

DROSHA rs642321 Polymorphism Influence Susceptibility to Childhood Acute Lymphoblastic Leukemia: A Preliminary Report

Introduction:

It has been well known that the microRNA biogenesis is involved in the pathogenesis of various diseases. We investigated the possible association between DROSHA rs642321 variant and risk of acute lymphocytic leukemia (ALL).

Materials and Methods:

We genotyped 75 children diagnosed with ALL and 115 age- and sex-matched children with no history of cancer of any type (as the control group) by the tetra amplification refractory mutation system-polymerase chain reaction.

Results:

We found that DROSHA rs642321 C > T variant significantly decreased the risk of ALL in codominant (TT vs. CC: odds ratio [OR] = 0.33, 95% confidence interval [CI] = 0.14–0.80, P = 0.020) and dominant (TT + CT vs. CC: OR = 0.51, 95% CI = 0.27–0.94, P = 0.037) inheritance model tested. The rs642321 T allele was associated with protective against ALL (OR = 0.58, 95% CI = 0.38–0.88, P = 0.011) in comparison with C allele.

Conclusion:

The study findings revealed that DROSHA rs642321 variant decreased the risk of pediatrics ALL in an Iranian population. Larger sample sizes with different ethnicities are needed to validate our findings.

MicroRNA biogenesis pathway genes polymorphisms and cancer risk: a systematic review and meta-analysis

MicroRNAs (miRNAs) may promote the development and progression of human cancers. Therefore, components of the miRNA biogenesis pathway may play critical roles in human cancer. Single nucleotide polymorphisms (SNPs) or mutations in genes involved in the miRNA biogenesis pathway may alter levels of gene expression, affecting disease susceptibility. Results of previous studies on genetic variants in the miRNA biogenesis pathway and cancer risk were inconsistent. Therefore, a meta-analysis is needed to assess the associations of these genetic variants with human cancer risk. We searched for relevant articles from PubMed, Web of Science, CNKI, and CBM through Jun 21, 2016. In total, 21 case-control articles met all of the inclusion criteria for the study. Significant associations were observed between cancer risk and the DGCR8polymorphism rs417309 G >A (OR 1.22, 95% CI [1.04-1.42]), as well as the DICER1 polymorphism rs1057035 TT (OR 1.13, 95% CI [1.05-1.22]). These SNPs exhibit high potential as novel diagnostic markers. Future studies with larger sample sizes and more refined analyses are needed to shed more light on these findings.

Clinical significance of microRNAs in chronic and acute human leukemia

Small non-coding microRNAs (miRNAs) are epigenetic regulators that target specific cellular mRNA to modulate gene expression patterns and cellular signaling pathways. miRNAs are involved in a wide range of biological processes and are frequently deregulated in human cancers. Numerous miRNAs promote tumorigenesis and cancer progression by enhancing tumor growth, angiogenesis, invasion and immune evasion, while others have tumor suppressive effects (Hayes, et al., Trends Mol Med 20(8): 460-9, 2014; Stahlhut and Slack, Genome Med 5 (12): 111, 2013). The expression profile of cancer miRNAs can be used to predict patient prognosis and clinical response to treatment (Bouchie, Nat Biotechnol 31(7): 577, 2013). The majority of miRNAs are intracellular localized, however circulating miRNAs have been detected in various body fluids and represent new biomarkers of solid and hematologic cancers (Fabris and Calin, Mol Oncol 10(3):503-8, 2016; Allegra, et al., Int J Oncol 41(6): 1897-912, 2012). This review describes the clinical relevance of miRNAs, lncRNAs and snoRNAs in the diagnosis, prognosis and treatment response in patients with chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML) and acute adult T-cell leukemia (ATL).

The functional role of microRNA in acute lymphoblastic leukemia: relevance for diagnosis, differential diagnosis, prognosis, and therapy

MicroRNAs (miRNAs), a new class of noncoding RNAs, which can hybridize to target messenger RNAs and regulate their expression posttranscriptionally, express differentially in distinct stages of lymphopoiesis and influence the direction of lymphoid precursor maturation. Hence, there is aberrant expression of miRNAs involved in malignant lymphopoiesis, and these aberrations can be used as signatures of acute lymphoblastic leukemia (ALL) with different subtypes. In addition, changes in the expression of several miRNAs may have functional relevance with leukemogenesis or drug resistance. As a result, the reversal of the expression of these miRNAs may alleviate the disease to some extent and improve clinical outcomes. However, among the studies of miRNAs, there are still some problems that need to be solved to understand the function of miRNAs in ALL more thoroughly.

Polymorphisms in miRNA processing genes and their role in osteosarcoma risk

BACKGROUND

The possible associations between genetic variants and osteosarcoma risk have been analyzed without conclusive results. Those studies were focused mainly on genes of biologically plausible pathways. However, recently, another pathway has acquired relevance in cellular transformation and tumorigenesis, the microRNA (miRNA) processing pathway. Dysregulation of the expression levels of genes in this pathway has been described in cancer. Consequently, single nucleotide polymorphisms (SNPs) in genes that codify for proteins involved in the miRNA processing pathway may affect miRNAs, and therefore their target genes, which might be associated with cancer development and progression. The aim of this study was to evaluate whether SNPs in miRNA processing genes confer predisposition to osteosarcoma.

PROCEDURE

We analyzed 72 SNPs in 21 miRNA processing genes in a total of 99 osteosarcoma patients and 387 controls.

RESULTS

A total of three SNPs were associated with osteosarcoma susceptibility. Interestingly, these SNPs were located in miRNA processing genes (CNOT1, CNOT4 and SND1) which are part of the RISC complex. Among them, the association of rs11866002 in CNOT1 was nearly significant after Bonferroni correction.

CONCLUSIONS

This study suggests that SNPs in RISC complex genes may be involved in osteosarcoma susceptibility, especially rs11866002 in CNOT1.

MicroRNA polymorphisms as markers of risk, prognosis and treatment response in hematological malignancies

MicroRNA dysregulation is a common event in hematological malignancies. Apart from genomic and epigenetic alterations, miRNA networks may be disturbed by polymorphisms in the miRNA regulatory pathway (miRSNPs). In this review we provide an overview of three categories of miRSNPs: (1) SNPs in genes involved in miRNA biogenesis and processing; (2) SNPs in miRNA genes; and (3) SNPs in miRNA binding sites in target genes and discuss their potential role as markers of disease risk, prognosis and treatment response in hematological cancers. Although so far only the tip of the iceberg has been touched, studies of polymorphisms in the miRNA regulatory pathways have already provided some clues for the mechanisms of miRNA dysregulation in cancer and open new perspectives in the management of hematological malignancies.

Multifunctional roles of the mammalian CCR4-NOT complex in physiological phenomena

The carbon catabolite repression 4 (CCR4)–negative on TATA-less (NOT) complex serves as one of the major deadenylases of eukaryotes. Although it was originally identified and characterized in yeast, recent studies have revealed that the CCR4–NOT complex also exerts important functions in mammals, -including humans. However, there are some differences in the composition and functions of the CCR4–NOT complex between mammals and yeast. It is noteworthy that each subunit of the CCR4–NOT complex has unique, multifunctional roles and is responsible for various physiological phenomena. This heterogeneity and versatility of the CCR4–NOT complex makes an overall understanding of this complex difficult. Here, we describe the functions of each subunit of the mammalian CCR4–NOT complex and discuss the molecular mechanisms by which it regulates homeostasis in mammals. Furthermore, a possible link between the disruption of the CCR4–NOT complex and various diseases will be discussed. Finally, we propose that the analysis of mice with each CCR4–NOT subunit knocked out is an effective strategy for clarifying its complicated functions and networks in mammals.

Prospective evaluation of whole genome microRNA expression profiling in childhood acute lymphoblastic leukemia

Dysregulation of microRNA (miRNA) expression contributes to the pathogenesis of several clinical conditions. The aim of this study is to evaluate the associations between miRNAs and childhood acute lymphoblastic leukemia (ALL) to discover their role in the course of the disease. Forty-three children with ALL and 14 age-matched healthy controls were included in the study. MicroRNA microarray expression profiling was used for peripheral blood and bone marrow samples. Aberrant miRNA expressions associated with the diagnosis and outcome were prospectively evaluated. Confirmation analysis was performed by real time RT-PCR. miR-128, miR-146a, miR-155, miR-181a, and miR-195 were significantly dysregulated in ALL patients at day 0. Following a six-month treatment period, the change in miRNA levels was determined by real time RT-PCR and expression of miR-146a, miR-155, miR-181a, and miR-195 significantly decreased. To conclude, these miRNAs not only may be used as biomarkers in diagnosis of ALL and monitoring the disease but also provide new insights into the potential roles of them in leukemogenesis.