The effect of miR-146a on STAT1 expression and apoptosis in acute lymphoblastic leukemia Jurkat cells

Role of microRNA-146a in cancer development by regulating apoptosis

Despite great advances in diagnostic and treatment options for cancer, like chemotherapy surgery, and radiation therapy it continues to remain a major global health concern. Further research is necessary to find new biomarkers and possible treatment methods for cancer. MicroRNAs (miRNAs), tiny non-coding RNAs found naturally in the body, can influence the activity of several target genes. These genes are often disturbed in diseases like cancer, which perturbs functions like differentiation, cell division, cell cycle, apoptosis and proliferation. MiR-146a is a commonly and widely used miRNA that is often overexpressed in malignant tumors. The expression of miR-146a has been correlated with many pathological and physiological changes in cancer cells, such as the regulation of various cell death paths. It's been established that the control of cell death pathways has a huge influence on cancer progression. To improve our understanding of the interrelationship between miRNAs and cancer cell apoptosis, it's necessary to explore the impact of miRNAs through the alteration in their expression levels. Research has demonstrated that the appearance and spread of cancer can be mitigated by moderating the expression of certain miRNA - a commencement of treatment that presents a hopeful approach in managing cancer. Consequently, it is essential to explore the implications of miR-146a with respect to inducing different forms of tumor cell death, and evaluate its potential to serve as a target for improved chemotherapy outcomes. Through this review, we provide an outline of miR-146a's biogenesis and function, as well as its significant involvement in apoptosis. As well, we investigate the effects of exosomal miR-146a on the promotion of apoptosis in cancer cells and look into how it could possibly help combat chemotherapeutic resistance.

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.

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.

Circulating miR-146a expression as a non-invasive predictive biomarker for acute lymphoblastic leukemia

Dysregulation of non-coding microRNAs during the course of tumor development, invasion and/or progression to the distant organs, makes them a promising candidate marker for the diagnosis of cancer and associated malignancies. This exploratory study aims at evaluating the usefulness of plasma concentration of circulating mir-146a as a non-invasive biomarker for acute lymphoblastic leukemia (ALL). Total RNA including miRNA was isolated from 110 plasma samples of patients (n = 66), healthy controls (n = 24) and follow up (n = 20) cases and reverse transcribed. Relative concentrations were assessed using real-time quantitative PCR and fold-change was calculated by 2^−ΔΔCt method. Finally, relative concentrations were correlated to clinicopathological factors. Patients (n = 66) were analyzed to determine fold expression of miR-146a in plasma samples of ALL. Before chemotherapy, pediatric (n = 42) and adult (n = 24) showed overexpression of miR-146a compared with healthy controls (P < 0.0001). There was no effect of age and gender on mir-146a expression in plasma. mirR-146a expression was independent of clinical and hematological features. Moreover, miR-146a levels in plasma of paired samples (n = 20) after treatment showed significant decrease in expression (P < 0.001). Expression of plasma miR-146a may be utilized as non-invasive marker to diagnose and predict prognosis in pediatric and adult patients with ALL. Moreover predicted targets may be utilized for ALL therapy in future.

Exosomes derived from chronic lymphocytic leukaemia cells transfer miR-146a to induce the transition of mesenchymal stromal cells into cancer-associated fibroblasts

Chronic lymphocytic leukaemia (CLL) is the most prevalent leukaemia and remains incurable. Mesenchymal stem cells (MSCs) can promote tumour progression by differentiating into cancer-associated fibroblasts (CAFs). However, the mechanisms by which tumour cells induce the transition of MSCs to CAFs are still largely undefined. Exosomes can regulate recipient cellular function by mediating intracellular communication. This study aimed to investigate whether CLL cells regulate the transition of bone marrow-derived MSCs (BM-MSCs) to CAFs via exosomal miR-146a delivery. The exosomes were isolated from CLL cell line MEC-1 (CLL-Exo) and then co-cultured with BM-MSCs. The expression of α-smooth muscle actin (α-SMA) and fibroblast-activated protein (FAP) were determined by immunofluorescence, quantitative real-time polymerase chain reaction and western blot. A luciferase reporter assay was performed to verify whether ubiquitin-specific peptidase 16 (USP16) was a target of miR-146a. CLL-Exo treatment up-regulated miR-146a and down-regulated expression of CAF markers (α-SMA and FAP) and USP16. The inducing effect of CLL-Exo on CAF marker expression was compromised when miR-146a expression was inhibited in CLL-Exo. USP16 was confirmed as a direct target of miR-146a and USP16 overexpression in BM-MSCs abrogated the CLL-Exo-mediated up-regulation of CAF markers. Collectively, CLL-Exo delivered miR-146a into BM-MSCs where miR-146a mediated transition of BM-MSCs into CAFs by targeting USP16.

Association Between the miR-146a Rs2910164 Polymorphism and Childhood Acute Lymphoblastic Leukemia Susceptibility in an Asian Population

Background:miR-146a has been demonstrated to be involved in normal hematopoiesis and the pathogenesis of many hematological malignancies by inhibiting the expression of its targets. Rs2910164(G>C) may modify the expression of the miR-146a gene, which might influence an individual's predisposition to childhood acute lymphoblastic leukemia (ALL). However, inconsistent findings have been reported on the association between the rs2910164(G>C) polymorphism and the risk of childhood ALL.

Methods: A comprehensive meta-analysis was performed to accurately estimate the association between the miR-146a rs2910164 polymorphism and childhood ALL among four different genetic models.

Results: This meta-analysis included Asian studies with a total of 1,543 patients and 1,816 controls. We observed a significant difference between patients and controls for the additive model (CC vs. GG: OR = 1.598, 95% CI: 1.003–2.545, P = 0.049) using a random effects model. Meanwhile, there was a trend of increased childhood ALL risk in the dominant model (CC + CG vs. GG: OR = 1.501, 95% CI: 0.976–2.307, P = 0.065), recessive model (CC vs. GG + CG: OR = 1.142, 95% CI: 0.946–1.380, P = 0.168) and allele model (C vs. G: OR = 1.217, 95% CI: 0.987–1.500, P = 0.066) between patients and controls.

Conclusions: Our findings suggest that the miR-146a rs2910164 CC genotype was significantly associated with childhood ALL susceptibility.

ETV6/RUNX1 Fusion Gene Abrogation Decreases the Oncogenicity of Tumour Cells in a Preclinical Model of Acute Lymphoblastic Leukaemia

BACKGROUND

The t(12;21)(p13;q22), which fuses ETV6 and RUNX1 genes, is the most common genetic abnormality in children with B-cell precursor acute lymphoblastic leukaemia. The implication of the fusion protein in leukemogenesis seems to be clear. However, its role in the maintenance of the disease continues to be controversial.

METHODS

Generation of an in vitroETV6/RUNX1 knock out model using the CRISPR/Cas9 gene editing system. Functional characterization by RNA sequencing, proliferation assays, apoptosis and pharmacologic studies, and generation of edited-cell xenograft model.

RESULTS

The expression of ETV6/RUNX1 fusion gene was completely eliminated, thus generating a powerful model on which to study the role of the fusion gene in leukemic cells. The loss of fusion gene expression led to the deregulation of biological processes affecting survival such as apoptosis resistance and cell proliferation capacity. Tumour cells showed higher levels of apoptosis, lower proliferation rate and a greater sensitivity to PI3K inhibitors in vitro along as a decrease in tumour growth in xenografts models after ETV6/RUNX1 fusion gene abrogation.

CONCLUSIONS

ETV6/RUNX1 fusion protein seems to play an important role in the maintenance of the leukemic phenotype and could thus become a potential therapeutic target.

The role of microRNAs in acute lymphoblastic leukaemia: From biology to applications

MicroRNAs (miRNAs) that are characterized by small, noncoding RNA have an essential role in the pathogenesis of human diseases, including cancer. Furthermore, miRNAs, as a new paradigm of epigenetic regulators, play an important role in normal development and cellular function. This literature review summarizes the recurrent mechanism of gene regulation through miRNAs and, consequently, the impact of regulated genes on different cellular processes, including proliferation, metastasis, prognosis, and apoptosis. Additionally, what is important to note is that the expression of miRNAs in various cancer cells is different, and miRNAs have various target genes in various cancers. Accordingly, a proper understanding of gene regulation by miRNAs contributes to new perspectives in miRNA-based therapeutic strategies. SIGNIFICANCE OF THE STUDY: MiRNAs are considered as a crucial regulator of gene expression. The genes also play an important role in the expression of miRNAs; as a result, there is a relationship between them. In recent years, targeted therapy with miRNAs has been a significant challenge. Studying the mechanisms through which miRNAs regulate various cancer cell processes, including apoptosis, proliferation, and metastasis, is very critical in the treatment of cancer through miRNAs. Definitely, a proper understanding of the impacts of aberrant expression of miRNAs on cancer cell processes leads to new therapeutic strategies in the targeted therapy with miRNAs.

miR-146a Deficiency Accelerates Hepatic Inflammation Without Influencing Diet-induced Obesity in Mice

miR-146a, an anti-inflammatory microRNA, is shown to be a negative regulator of adipocyte inflammation. However, the functional contribution of miR-146a in the development of obesity is not defined. In order to determine whether miR-146a influences diet-induced obesity, mice that were either wild type (WT) or miR-146a deficient (KO) were fed with high (60% kcal) fat diet (HFD) for 16 weeks. Deficiency of miR-146a did not influence obesity measured as HFD-induced body weight and fat mass gain, or metabolism of glucose and insulin tolerance. In addition, adipocyte apoptosis, adipose tissue collagen and macrophage accumulation as detected by TUNEL, Picro Sirius and F4/80 immunostaining, respectively, were comparable between the two groups of mice. Although, miR-146a deficiency had no influence on HFD-induced hepatic lipid accumulation, interestingly, it significantly increased obesity-induced inflammatory responses in liver tissue. The present study demonstrates that miR-146a deficiency had no influence on the development of HFD-induced obesity and adipose tissue remodeling, whereas it significantly increased hepatic inflammation in obese mice. This result suggests that miR-146a regulates hepatic inflammation during development of obesity.

Transcriptome analysis identifies key regulators and networks in Acute myeloid leukemia

OBJECTIVES

Acute myeloid leukemia (AML) is a heterogeneous and highly recurrent hematological malignancy. Studies have shown an association between microRNAs and drive genes in AMLs. However, the regulatory roles of miRNAs in AML and how they act on downstream targets and the signaling pathway has been little studied.

METHODS

As to understand the mechanism of mRNA-miRNA interaction in the blood malignancy from a large scale of transcriptomic sequencing studies, we applied a comprehensive miRNA-mRNA association, co-expression gene network and ingenuity pathway analysis using TCGA AML datasets.

RESULTS

Our results showed that his-mir-335 was a critical regulatory of homeobox A gene family. PBX3, KAT6A, MEIS1, and COMMD3-BMI1 were predicted as top transcription regulators in the regulatory network of the HOXA family. The most significantly enriched functions were cell growth, proliferation, and survival in the mRNA-miRNA network.

CONCLUSION

Our work revealed that regulation of the HOXA gene family and its regulation played an important role in the development of AML.

A genetic variant in miR-100 is a protective factor of childhood acute lymphoblastic leukemia

BACKGROUND

In the past decade, miR-100, miR-146a, and miR-210 were reported to be dysregulated in childhood acute lymphoblastic leukemia (ALL). However, effects of genetic variants in these three microRNAs have not been investigated in Chinese population.

METHODS

In this study, we conducted a case-control study to evaluate the relationship between genetic variants in miR-100, miR-146a, and miR-210 and the risk of childhood ALL in Chinese population. Subsequently, plasma expression level of miR-100 was also detected.

RESULT

We found that subjects carrying mutant homozygous TT genotype of miR-100 rs543412 had a statistically significantly decreased risk of childhood ALL (adjusted odds ratio [OR] = 0.73, 95% confidence interval [CI] = 0.55-0.97, P = 0.029). This protective effect was also observed among subjects whose parents were ever drinkers (adjusted OR = 0.53, 95% CI = 0.29-0.94), or whose living house were ever painted (adjusted OR = 0.57, 95% CI = 0.34-0.94). Besides, rs543412 variant homozygous TT had a significantly protective role in patients with childhood B-ALL. Finally, we found that expression level of miR-100 in plasma of childhood ALL cases was significantly higher than that of noncancer controls.

CONCLUSION

Our study suggested that there was significant association between the polymorphisms in miR-100 (rs543412) and decreased susceptibility to childhood ALL.

A 4-microRNA signature for survival prognosis in pediatric and adolescent acute myeloid leukemia

Acute myeloid leukemia (AML) is a hematologic malignancy with significant molecular heterogeneity. MicroRNAs (miRNAs) play a critical role in AML diagnosis, pathogenesis, and prognosis of AML. Little has been done to identify a miRNA signature in pediatric and adolescent patients for predicting overall survival. This study aims to identify a panel of miRNA signature that could predict the prognosis of all younger AML patients with all subtypes of AML by analyzing data from The Cancer Genome Atlas (TCGA). A total of 229 patients under 23 years with miRNA data and corresponding clinical data from TCGA database were enrolled in this study. Through conducting multivariate analysis in the training test, it was identified that the high expression of hsa-miR-509 and hsa-miR-542 were independent poor prognostic factors, whereas that of hsa-miR-146a and hsa-miR-3667 had a trend to be favorable factors. A 4-miRNA signature was constructed by these miRNAs considering the weight of each. In testing group and all 229 patients' cohort as well as 59 cytogenetically normal AML (CN-AML) patients' cohort, higher risk score was associated with shorter overall survival (OS). All results were confidential by using powerful statistical analysis. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis were carried out to further develop leukemia-relevant mechanisms supporting the model. The results indicate that the 4-miRNA-based signature is a reliable prognostic biomarker for pediatric and adolescent AML patients.