miR-16-5p Promotes Erythroid Maturation of Erythroleukemia Cells by Regulating Ribosome Biogenesis

DNA Damage-Inducing 10-Methoxy-canthin-6-one (Mtx-C) Promotes Cell Cycle Arrest in G2/M and Myeloid Differentiation of Acute Myeloid Leukemias and Leukemic Stem Cells

Synthetic 10-methoxy-canthin-6-one (Mtx-C), an alkaloid derivative, exhibits cytotoxic effects against acute myeloid cells (AMLs) and leukemic stem cells (LSCs) at a concentration of approximately 60 μM. However, the antitumor mechanism of Mtx-C in AMLs and LSCs remains elusive. Using Mtx-C at concentrations with low cytotoxicity (2-4 μM) for 72 h, we observed cell arrest with the accumulation of cells in the G2/M phase of the cell cycle. This effect was controlled by cyclin B1 expression and induction of the DNA damage cascade characterized by ATM, ATR, Chk1/2, p53, and H2A.X phosphorylation. Molecular docking analysis confirmed Mtx-C as a DNA intercalator. Moreover, the expression of inhibitors of cyclin-dependent kinases, including p21 (Cip1) and p27 (Kip1), increased. In addition, several miRNAs that are considered oncosuppressors were regulated by Mtx-C in Kasumi-1 cells. Finally, concomitant with cell cycle arrest, the underlying molecular mechanisms of Mtx-C in AML cells include myeloid differentiation, as evidenced by the increased expression of PU.1, myeloperoxidase, CD15, CD11b, and CD14 in the AML and LSC populations with the participation of p38 mitogen-activated protein kinase. Thus, we showed that Mtx-C simultaneously induced cell cycle arrest and myeloid differentiation in AML lineages and in the LSC population, providing insights into new therapeutic alternatives for the treatment of AML based on naturally occurring molecules.

Insight into microRNAs' involvement in hematopoiesis: current standing point of findings

Hematopoiesis is a complex process in which hematopoietic stem cells are differentiated into all mature blood cells (red blood cells, white blood cells, and platelets). Different microRNAs (miRNAs) involve in several steps of this process. Indeed, miRNAs are small single-stranded non-coding RNA molecules, which control gene expression by translational inhibition and mRNA destabilization. Previous studies have revealed that increased or decreased expression of some of these miRNAs by targeting several proto-oncogenes could inhibit or stimulate the myeloid and erythroid lineage commitment, proliferation, and differentiation. During the last decades, the development of molecular and bioinformatics techniques has led to a comprehensive understanding of the role of various miRNAs in hematopoiesis. The critical roles of miRNAs in cell processes such as the cell cycle, apoptosis, and differentiation have been confirmed as well. However, the main contribution of some miRNAs is still unclear. Therefore, it seems undeniable that future studies are required to focus on miRNA activities during various hematopoietic stages and hematological malignancy.

Static electromagnetic field and recombinant human fibroblasts encoding miR-451 and miR-16 increased cell trans-differentiation to CD71+ and CD235a+ erythroid like progenitor

Introduction

Ex vivo blood production is an urgent need of most countries, and creating production protocols can save the lives of many patients. Despite the recent advances in blood production in ex vivo conditions, its high-scale production is not yet possible, and requires further studies. Therefore, by transfecting fibroblast cells with miR-16, and miR-451 genes, as well as applying low frequency electromagnetic fields (ELF-EMF) treatment, we tried to increase the differentiation of these cells into CD71+ and CD235a+ erythroid like progenitors.

Methods

After preparation, and cultivation of human dermal transgenic fibroblast cells, they were transfected by Plenti3-hsa-miR451, Plenti3-hsa-miR16 and Plenti3-backbone inserted into E. coli Stbl4 genome. Then, transgenic fibroblast cells were treated with 10mT ELF-EMF every day for 20 minutes for 7 days. Using a flow cytometer, the expressions of CD71, and CD235a were studied in these cells, and the expressions of genes involved in hematopoiesis were studied using the RT-PCR technique.

Results

The results indicated an increase in the differentiation of fibroblast cells treated with 10mT ELF-EMF to erythroid like progenitors. Furthermore, the percentage of CD71+ and CD235a+ cells was the highest in irradiated cells encoding miR-16 and miR-451, which indicates their differentiation into erythroid like progenitors. Also, in the transgenic cells treated with ELF-EMF, an increase in the expressions of α-chain, β-chain, γ-chain and GATA1 genes was observed, which indicates the potential of these cells for hematopoiesis. However, there was no significant difference in the expression of CD34 and CD38 genes in these cell lines.

Conclusion

Both ELF-EMF and upregulations of miR-16 and miR-451 lead to improved differentiation of fibroblast cells into erythroid like progenitors.

A review on the role of mir-16-5p in the carcinogenesis

miR-16-5p is microRNA with important roles in the development of diverse malignancies including neuroblastoma, osteosarcoma, hepatocellular carcinoma, cervical cancer, breast cancer, brain tumors, gastrointestinal cancers, lung cancer and bladder cancer. This miRNA has 22 nucleotides. hsa-miR-16-5p is produced by MIR16-1 gene. First evidence for its participation in the carcinogenesis has been obtained by studies reporting deletion and/or down-regulation of these miRNAs in chronic lymphocytic leukemia. Subsequent studies have shown down-regulation of miR-16-5p in a variety of cancer cell lines and clinical samples. Besides, tumor suppressor role of miR-16-5p has been verified in animal models of different types of cancers. Studies in these models have shown that over-expression of this miRNA or modulation of expression of lncRNAs that sponge this miRNA can block carcinogenic processes. In the current review, we summarize function of miR-16-5p in the development and progression of different cancers.

Invariable Ribosome Stoichiometry During Murine Erythroid Differentiation: Implications for Understanding Ribosomopathies

Heterogeneity of the main ribosomal composition represents an emerging, yet debatable, mechanism of gene expression regulation with a purported role in ribosomopathies, a group of disorders caused by mutations in ribosomal protein genes (RPs). Ribosomopathies, mysteriously relate with tissue-specific symptoms (mainly anemia and cancer predisposition), despite the ubiquitous expression and necessity of the associated RPs. An outstanding question that may shed light into disease pathogenicity and provide potential pharmacological interventions, is whether and how the ribosomal composition is modified during, the highly affected by RP mutations, process of erythroid differentiation. To address this issue, we analyzed ribosome stoichiometry using an established model of erythroid differentiation, through sucrose gradient ultracentrifugation and quantitative proteomics. We found that differentiation associates with an extensive reprogramming of the overall ribosomal levels, characterized by an increase in monosomes and a decrease in polysomes. However, by calculating a stoichiometry score for each independent ribosomal protein, we found that the main ribosomal architecture remained invariable between immature and differentiated cells. In total, none of the 78 Ribosomal Proteins (RPs- 74 core RPs, Rack1, Fau and 2 paralogs) detected was statistically different between the samples. This data was further verified through antibody-mediated quantification of 6 representative RPs. Moreover, bioinformatic analysis of whole cell proteomic data derived out of 4 additional models of erythropoiesis revealed that RPs were co-regulated across these cell types, too. In conclusion, ribosomes maintain an invariant protein stoichiometry during differentiation, thus excluding ribosome heterogeneity from a potential mechanism of toxicity in ribosomopathies and other erythroid disorders.

Comprehensive Analysis of microRNAs in Human Adult Erythropoiesis

MicroRNAs (miRNAs) are small non-coding RNAs, which play an important role in various cellular and developmental processes. The study of miRNAs in erythropoiesis is crucial to uncover the cellular pathways that are modulated during the different stages of erythroid differentiation. Using erythroid cells derived from human CD34+ hematopoietic stem and progenitor cells (HSPCs)and small RNA sequencing, our study unravels the various miRNAs involved in critical cellular pathways in erythroid maturation. We analyzed the occupancy of erythroid transcription factors and chromatin accessibility in the promoter and enhancer regions of the differentially expressed miRNAs to integrate miRNAs in the transcriptional circuitry of erythropoiesis. Analysis of the targets of the differentially expressed miRNAs revealed novel pathways in erythroid differentiation. Finally, we described the application of Clustered regularly interspaced short palindromic repeats-Cas9 (CRISPR-Cas9) based editing of miRNAs to study their function in human erythropoiesis.