Assessment of microRNA expression in leukemic cells as predictors of sensitivity to purine nucleoside analogs, fludarabine and cladribine, in chronic lymphocytic leukemia patients

miRNA Biology in Chronic Lymphocytic Leukemia

microRNAs (miRNAs) are a class of small non-coding RNAs that play a crucial regulatory role in fundamental biological processes and have been implicated in various diseases, including cancer. The first evidence of the cancer-related function of miRNAs was discovered in chronic lymphocytic leukemia (CLL) in the early 2000s. Alterations in miRNA expression have since been shown to strongly influence the clinical course, prognosis, and response to treatment in patients with CLL. Therefore, the identification of specific miRNA alterations not only enhances our understanding of the molecular mechanisms underlying CLL but also holds promise for the development of novel diagnostic and therapeutic strategies. This review aims to provide a comprehensive summary of the current knowledge and recent insights into miRNA dysregulation in CLL, emphasizing its pivotal roles in disease progression, including the development of the lethal Richter syndrome, and to provide an update on the latest translational research in this field.

MicroRNAs: Potential prognostic and theranostic biomarkers in chronic lymphocytic leukemia

Small noncoding ribonucleic acids called microRNAs coordinate numerous critical physiological and biological processes such as cell division, proliferation, and death. These regulatory molecules interfere with the function of many genes by binding the 3'-UTR region of target mRNAs to inhibit their translation or even degrade them. Given that a large proportion of miRNAs behave as either tumor suppressors or oncogenes, any genetic or epigenetic aberration changeing their structure and/or function could initiate tumor formation and development. An example of such cancers is chronic lymphocytic leukemia (CLL), the most prevalent adult leukemia in Western nations, which is caused by unregulated growth and buildup of defective cells in the peripheral blood and lymphoid organs. Genetic alterations at cellular and molecular levels play an important role in the occurrence and development of CLL. In this vein, it was noted that the development of this disease is noticeably affected by changes in the expression and function of miRNAs. Many studies on miRNAs have shown that these molecules are pivotal in the prognosis of different cancers, including CLL, and their epigenetic alterations (e.g., methylation) can predict disease progression and response to treatment. Furthermore, miRNAs are involved in the development of drug resistance in CLL, and targeting these molecules can be considered a new therapeutic approach for the treatment of this disease. MiRNA screening can offer important information on the etiology and development of CLL. Considering the importance of miRNAs in gene expression regulation, their application in the diagnosis, prognosis, and treatment of CLL is reviewed in this paper.

miRNAs as cornerstones in chronic lymphocytic leukemia pathogenesis and therapeutic resistance- An emphasis on the interaction of signaling pathways

Chronic lymphocytic leukemia (CLL) accounts for the vast majority of cases of leukemia. Patients of advanced age are more likely to develop the condition, which has a highly varied clinical course. Consideration of illness features and preceding treatment sequence, as well as patient preferences and comorbidities, is necessary for selecting the appropriate treatment for the appropriate patient. Therefore, there is an urgent need for novel biomarkers with high sensitivity and specificity to detect CLL early, monitor CLL patients, select the treatment responders, and reduce ineffective treatment, unwanted side effects, and unnecessary expenses. In both homeostasis and illness, microRNAs (miRNAs/miRs) play a vital role as master regulators of gene expression and, by extension, protein expression. MiRNAs typically reduce the stability of mRNAs, including those encoding genes involved in tumorigenesis processes as cell cycle regulation, inflammation, stress response, angiogenesis, differentiation, apoptosis, and invasion. Due to their unique properties, miRNAs are rapidly being exploited as accurate biomarkers for illness detection, and medicines based on miRNA targets are finding widespread application in clinical practice. Accordingly, the current review serves as a quick primer on CLL and the biogenesis of miRNAs. In addition to providing a brief overview of the miRNAs whose function in the progression of CLL has been established by recent in vitro or in vivo research through articulating the influence of these miRNAs on a wide variety of cellular functions, including increased proliferative potential; support for angiogenesis; cell cycle aberration; evasion of apoptosis; promotion of metastasis; and reduced sensitivity to specific treatments.

miRNAs in Lymphocytic Leukaemias-The miRror of Drug Resistance

Refractory disease and relapse remain the main causes of cancer therapy failure. Refined risk stratification, treatment regimens and improved early diagnosis and detection of minimal residual disease have increased cure rates in malignancies like childhood acute lymphoblastic leukaemia (ALL) to 90%. Nevertheless, overall survival in the context of drug resistance remains poor. The regulatory role of micro RNAs (miRNAs) in cell differentiation, homeostasis and tumorigenesis has been under extensive investigation in different cancers. There is accumulating data demonstrating the significance of miRNAs for therapy outcomes in lymphoid malignancies and some direct demonstrations of the interplay between these small molecules and drug response. Here, we summarise miRNAs' impact on chemotherapy resistance in adult and paediatric ALL and chronic lymphocytic leukaemia (CLL). The main focus of this review is on the modulation of particular signaling pathways like PI3K-AKT, transcription factors such as NF-κB, and apoptotic mediators, all of which are bona fide and pivotal elements orchestrating the survival of malignant lymphocytic cells. Finally, we discuss the attractive strategy of using mimics, antimiRs and other molecular approaches pointing at miRNAs as promising therapeutic targets. Such novel strategies to circumvent ALL and CLL resistance networks may potentially improve patients' responses and survival rates.

CARD11 is a novel target of miR-181b that is upregulated in chronic lymphocytic leukemia

Aim: To investigate the targets of miR-181b in patients with chronic lymphocytic leukemia (CLL). Materials & methods: The bioinformatic softwares were used to indicate the key target genes associated with miR-181b, and the results were verified in CLL patient samples and 293T cells. Results: CARD11 is a potential target gene of miR-181b, an inverse relationship was revealed between the expression of CARD11 and miR-181b in 104 CLL patients, and it was confirmed in vitro with luciferase assays and western blotting. Kaplan-Meier analysis showed that CLL patients with high CARD11 expression demonstrated poor survival. Conclusion: CARD11 is a novel target of miR-181b that is upregulated, which could be a poor prognostic indicator for CLL patients.

Downregulated miR‑130a enhances the sensitivity of acute myeloid leukemia cells to Adriamycin

MicroRNA (miR)-130a has been reported to promote cancer growth; however, its role during acute myeloid leukemia (AML) is not completely understood. In the present study, the effects of miR-130a on the sensitivity of AML cells to Adriamycin (Adr) were investigated. 5-Aza-2′-deoxycytidine (5-Aza-dC) was used to stimulate Adr resistance in AML cells, and cell viability and miR-130a expression were determined using the Cell Counting Kit-8 (CCK-8) assay and reverse transcription-quantitative PCR, respectively. miR-130a overexpression and knockdown in Adr-resistant AML cells was performed to investigate the proliferative and invasive abilities of the cells using CCK-8 and Transwell assays, respectively. Furthermore, the effects of miR-130a on the expression of epithelial-mesenchymal transition (EMT)-related proteins in Adr-resistant AML cells were detected using western blot analysis. Pre-treatment with 5-Aza-dC enhanced the cell viability and miR-130a expression of Adr-treated AML cells. Adr and miR-130a expression showed a dose-dependent relationship, with miR-130a expression decreasing with increasing Adr concentrations. Moreover, miR-130a overexpression alleviated the inhibitory effects of Adr on cell viability and invasion, while miR-130a knockdown enhanced the sensitivity of AML cells to Adr. Furthermore, Adr exerted an inhibitory effect on EMT in AML cells, which was rescued by miR-130a overexpression and enhanced by miR-130a knockdown. miR-130a knockdown also increased the sensitivity of AML cells to Adr by decreasing cell viability, invasion and EMT. Therefore, miR-130a knockdown is a potential therapeutic strategy for Adr-resistant AML.