Hsa-miR-155-5p drives aneuploidy at early stages of cellular transformation

Role of microRNAs in Chronic Lymphocytic Leukemia

Chronic Lymphocytic Leukemia (CLL) is the most common form of leukemia in adults, with a highly variable clinical course. Improvement in the knowledge of the molecular pathways behind this disease has led to the development of increasingly specific therapies, such as BCR signaling inhibitors and BCL-2 inhibitors. In this context, the emerging role of microRNAs (miRNAs) in CLL pathophysiology and their possible application in therapy is worth noting. MiRNAs are one of the most important regulatory molecules of gene expression. In CLL, they can act both as oncogenes and tumor suppressor genes, and the deregulation of specific miRNAs has been associated with prognosis, progression, and drug resistance. In this review, we describe the role of the miRNAs that primarily impact the disease, and how these miRNAs could be used as therapeutic tools. Certainly, the use of miRNAs in clinical practice is still limited in CLL. Many issues still need to be solved, particularly regarding their biological and safety profile, even if several studies have suggested their efficacy on the disease, alone or in combination with other drugs.

Identification of microRNA editing sites in three subtypes of leukemia

Leukemia is an aberrant hyper-proliferation of immature blood cells that do not form solid tumors. The transcriptomes of microRNAs (miRNAs) of leukemia have been intensively explored. However, miRNA editing of leukemia has not been extensively studied. To identify miRNA editing patterns and explore their functional relevance in leukemia, we analyzed 200 small RNA sequencing profiles of three subtypes of leukemia and identified hundreds of miRNA editing sites in three subtypes of leukemia. Then, we compared the editing levels of identified miRNA editing sites in leukemia and normal controls. Many miRNAs were differential edited in different subtypes of leukemia. We also found the editing levels of 3'-A editing sites of hsa-mir-21-5p and hsa-mir-155-5p decreased in chronic lymphocytic leukemia patients with radiation treatments. By integrating PAR-CLIP sequencing profiles, we predicted the targets of original and edited miRNAs. One of the edited miRNA, hsa-let-7b_5c, with an additional cytosine at 5' end of hsa-let-7b-5p, potentially targeted VBP1 and CTDSP1. CTDSP1 was significantly downregulated in T-ALL compared to normal controls, which might be originated from the hyperediting of hsa-let-7b-5p in T-ALL. Our study provides a comprehensive view of miRNA editing in three different subtypes of leukemia.

miRNA dysregulation is an emerging modulator of genomic instability

Genomic instability consists of a range of genetic alterations within the genome that contributes to tumor heterogeneity and drug resistance. It is a well-established characteristic of most cancer cells. Genome instability induction results from defects in DNA damage surveillance mechanisms, mitotic checkpoints and DNA repair machinery. Accumulation of genetic alterations ultimately sets cells towards malignant transformation. Recent studies suggest that miRNAs are key players in mediating genome instability. miRNAs are a class of small RNAs expressed in most somatic tissues and are part of the epigenome. Importantly, in many cancers, miRNA expression is dysregulated. Consequently, this review examines the role of miRNA dysregulation as a causal step for induction of genome instability and subsequent carcinogenesis. We focus specifically on mechanistic studies assessing miRNA(s) and specific subtypes of genome instability or known modes of genome instability. In addition, we provide insight on the existing knowledge gaps within the field and possible ways to address them.

Oncogenesis and Tumor Inhibition by MicroRNAs and its Potential Therapeutic Applications: A Systematic Review

MicroRNAs appear as small molecule modifiers, which improve many new findings and mechanical illustrations for critically important biological phenomena and pathologic events. The best-characterized non-coding RNA family consists of about 2600 human microRNAs. Rich evidence has revealed their crucial importance in maintaining normal development, differentiation, growth control, aging, modulation of cell survival or apoptosis, as well as migration and metastasis as microRNAs dysregulation leads to cancer incidence and progression. By far, microRNAs have recently emerged as attractive targets for therapeutic intervention. The rationale for developing microRNA therapeutics is based on the premise that aberrantly expressed microRNAs play a significant role in the emergence of a variety of human diseases ranging from cardiovascular defects to cancer, and that repairing these microRNA deficiencies by either antagonizing or restoring microRNA function may yield a therapeutic benefit. Although microRNA antagonists are conceptually similar to other inhibitory therapies, improving the performance of microRNAs by microRNA replacement or inhibition that is a less well- described attitude. In this assay, we have condensed the last global knowledge and concepts regarding the involvement of microRNAs in cancer emergence, which has been achieved from the previous studies, consisting of the regulation of key cancer-related pathways, such as cell cycle control and the DNA damage response and the disruption of profile expression in human cancer. Here, we have reviewed the special characteristics of microRNA replacement and inhibition therapies and discussed explorations linked with the delivery of microRNA mimics in turmeric cells. Besides, the achievement of biomarkers based on microRNAs in clinics is considered as novel non-invasive biomarkers in diagnostic and prognostic assessments.

Can microRNA become next-generation tools in molecular diagnostics and therapeutics? A systematic review

Background

MicroRNAs (miRNAs) represent a novel class of single-stranded RNA molecules of 18–22 nucleotides that serve as powerful tools in the regulation of gene expression. They are important regulatory molecules in several biological processes.

Main body

Alteration in the expression profiles of miRNAs have been found in several diseases. It is anticipated that miRNA expression profiling can become a novel diagnostic tool in the future.

Hence, this review evaluates the implications of miRNAs in various diseases and the recent advances in miRNA expression level detection and their target identification. A systematic approach to review existing literature available on databases such as Medline, PubMed, and EMBASE was conducted to have a better understanding of mechanisms mediating miRNA-dependent gene regulation and their role as diagnostic markers and therapeutic agents.

Conclusion

A clear understanding of the complex multilevel regulation of miRNA expression is a prerequisite to explicate the origin of a wide variety of diseases. It is understandable that miRNAs offer potential targets both in diagnostics and therapeutics of a multitude of diseases. The inclusion of specific miRNA expression profiles as biomarkers may lead to crucial advancements in facilitating disease diagnosis and classification, monitoring its prognosis, and treatment. However, standardization of methods has a pivotal role in the success of extensive use of miRNA expression profiling in routine clinical settings.

Biosafety evaluation of culture-expanded human chondrocytes with growth factor cocktail: a preclinical study

The scarcity of chondrocytes is a major challenge for cartilage tissue engineering. Monolayer expansion is necessary to amplify the limited number of chondrocytes needed for clinical application. Growth factors are often added to improve monolayer culture conditions, promoting proliferation, and enhancing chondrogenesis. Limited knowledge on the biosafety of the cell products manipulated with growth factors in culture has driven this study to evaluate the impact of growth factor cocktail supplements in chondrocyte culture medium on chondrocyte genetic stability and tumorigenicity. The growth factors were basic fibroblast growth factor (b-FGF), transforming growth factor β2 (TGF β2), insulin-like growth factor 1 (IGF-1), insulin-transferrin-selenium (ITS), and platelet-derived growth factor (PD-GF). Nasal septal chondrocytes cultured in growth factor cocktail exhibited a significantly high proliferative capacity. Comet assay revealed no significant DNA damage. Flow cytometry showed chondrocytes were mostly at G0-G1 phase, exhibiting normal cell cycle profile with no aneuploidy. We observed a decreased tumour suppressor genes’ expression (p53, p21, pRB) and no TP53 mutations or tumour formation after 6 months of implantation in nude mice. Our data suggest growth factor cocktail has a low risk of inducing genotoxic and tumorigenic effects on chondrocytes up to passage 6 with 16.6 population doublings. This preclinical tumorigenicity and genetic instability evaluation is crucial for further clinical works.

Role of Non-Coding RNAs in the Development of Targeted Therapy and Immunotherapy Approaches for Chronic Lymphocytic Leukemia

In the past decade, novel targeted therapy approaches, such as BTK inhibitors and Bcl2 blockers, and innovative treatments that regulate the immune response against cancer cells, such as monoclonal antibodies, CAR-T cell therapy, and immunomodulatory molecules, have been established to provide support for the treatment of patients. However, drug resistance development and relapse are still major challenges in CLL treatment. Several studies revealed that non-coding RNAs have a main role in the development and progression of CLL. Specifically, microRNAs (miRs) and tRNA-derived small-RNAs (tsRNAs) were shown to be outstanding biomarkers that can be used to diagnose and monitor the disease and to possibly anticipate drug resistance and relapse, thus supporting physicians in the selection of treatment regimens tailored to the patient needs. In this review, we will summarize the most recent discoveries in the field of targeted therapy and immunotherapy for CLL and discuss the role of ncRNAs in the development of novel drugs and combination regimens for CLL patients.

MiR-155-5p exerts tumor-suppressing functions in Wilms tumor by targeting IGF2 via the PI3K signaling pathway

BACKGROUND

MicroRNA-155-5p (miR-155-5p) has been reported to play an oncogenic role in different human malignancies; however, its role in Wilms tumor (WT) remains unclear.

METHODS

Differentially expressed miRNAs (DE-miRNAs) and mRNAs (DEGs) in WT blood and tissues were identified by using miRNA microarray and RNA-sequencing. Bioinformatics prediction and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to predict the potential functions of DE-miRNAs. DE-miRNAs and DEGs in WT obtained from Gene Expression Omnibus (GEO) and Therapeutically Applicable Research to Generate Effective Treatments (TARGET) were identified by using the "edgeR" package. RT-qPCR was used to explore miR-155-5p and IGF2 expression and their clinical significance in WT specimens. A rhabdoid cell line (G401) and Ewing sarcoma cell line (SK-NEP-1) were used. Immunohistochemical staining, western blotting and dual-luciferase reporter assays were performed to study the mechanisms involved. The CCK-8, flow cytometry, wound healing and transwell assays were performed to identify the effects of miR-155-5p and IGF2 knockdown on cell proliferation, apoptosis, migration and invasion, respectively.

RESULTS

MiR-155-5p was downregulated in both blood and tissues from WT patients who did not receive chemotherapy before surgery but was upregulated in tissues from WT patients who had received chemotherapy before surgery. IGF2, PI3K, AKT and mTOR were found to be upregulated in WT tissues. Additionally, miR-155-5p and IGF2 were significantly correlated with TNM stage and lymphatic metastasis in WT patients. Molecular mechanism exploration indicated that IGF2 was downregulated by miR-155-5p via direct binding to its 3' untranslated region in cell lines. Furthermore, IGF2, PI3K, AKT and mTOR expression was inversely correlated with miR-155-5p expression, and PI3K, AKT and mTOR expression was positively correlated with IGF2 expression in cell culture. Functional studies demonstrated that miR-155-5p upregulation and IGF2 knockdown suppressed cell proliferation, migration and invasion and induced cell apoptosis. Moreover, the tumor-suppressing effects of miR-155-5p in cells were abrogated by miR-155-5p inhibitor treatment.

CONCLUSIONS

Taken together, these findings suggest that miR-155-5p functions as a tumor suppressor in WT through inactivating the PI3K/AKT/mTOR signaling pathway by directly targeting IGF2. Thus, miR-155-5p might be a novel therapeutic target for WT.

HNRNPL Restrains miR-155 Targeting of BUB1 to Stabilize Aberrant Karyotypes of Transformed Cells in Chronic Lymphocytic Leukemia

Aneuploidy and overexpression of hsa-miR-155-5p (miR-155) characterize most solid and hematological malignancies. We recently demonstrated that miR-155 sustains aneuploidy at early stages of in vitro cellular transformation. During in vitro transformation of normal human fibroblast, upregulation of miR-155 downregulates spindle checkpoint proteins as the mitotic checkpoint serine/threonine kinase budding uninhibited by benzimidazoles 1 (BUB1), the centromere protein F (CENPF) and the zw10 kinetochore protein (ZW10), compromising the chromosome alignment at the metaphase plate and leading to aneuploidy in daughter cells. Here we show that the heterogeneous nuclear ribonucleoprotein L (HNRNPL) binds to the polymorphic marker D2S1888 at the 3′UTR of BUB1 gene, impairs the miR-155 targeting, and restores BUB1 expression in chronic lymphocytic leukemia. This mechanism occurs at advanced passages of cell transformation and allows the expansion of more favorable clones. Our findings have revealed, at least in part, the molecular mechanisms behind the chromosomal stabilization of cell lines and the concept that, to survive, tumor cells cannot continuously change their genetic heritage but need to stabilize the most suitable karyotype.

MicroRNAs in Autoimmunity and Hematological Malignancies

Autoimmunity and hematological malignancies are often concomitant in patients. A causal bidirectional relationship exists between them. Loss of immunological tolerance with inappropriate activation of the immune system, likely due to environmental and genetic factors, can represent a breeding ground for the appearance of cancer cells and, on the other hand, blood cancers are characterized by imbalanced immune cell subsets that could support the development of the autoimmune clone. Considerable effort has been made for understanding the proteins that have a relevant role in both processes; however, literature advances demonstrate that microRNAs (miRNAs) surface as the epigenetic regulators of those proteins and control networks linked to both autoimmunity and hematological malignancies. Here we review the most up-to-date findings regarding the miRNA-based molecular mechanisms that underpin autoimmunity and hematological malignancies.