miR-155 and miR-223 as markers of biological and clinical features of chronic lymphocytic leukemia

Introduction. Chronic lymphocytic leukemia (CLL) is a disease characterized by large individual differences both in the clinical course and in molecular patterns of expression of genes and regulatory RNAs, which can influence pathological changes. The involvement of regulatory microRNAs miR-155 and miR-223 in the pathogenesis of CLL is fairly well known, but there is insufficient information about possible fluctuations in the expression of miR-155 and miR-223 depending on the time course of pathology development and on parameters of medical treatment. Purpose – to investigate the expression of miR-155 and miR-223 in patients having CLL with different biological and clinical features and different characteristics of treatment in terms of peripheral-blood substrates (plasma, lymphocytes, and extracellular vesicles) and bone marrow. Material and Methods. This work involved samples of peripheral blood and bone marrow from 38 patients with a diagnosis of CLL from the City Hematology Center at the government-funded healthcare institution (Novosibirsk Oblast) City Clinical Hospital No. 2 from the years 2016 to 2017. Assessment of miR-155 and miR-223 expressions was carried out by reverse-transcription real-time PCR according to the TaqMan principle. Significance of differences between groups was evaluated either by the nonparametric Mann–Whitney test or by the nonparametric Kruskal–Wallis test with subsequent pairwise comparisons via the Mann–Whitney test. Results. High variation of the analyzed parameters was found. The expression levels of miR-155 and miR-223 in microvesicles of patients with unfavorable chromosomal anomalies were lower than those in patients with the chromosomal aberrations (or the normal karyotype) associated with a moderate effect on CLL prognosis. The expression level of miR-223 in peripheral blood lymphocytes of untreated patients with CLL was higher than that observed in treated patients. Conclusion. differences in the expression levels of miR-155 and miR-223 were identified depending on chromosomal aberrations and polychemotherapy. Our preliminary results will provide the basis for future larger studies on levels of microRNAs in CLL patients having specific features of the development, clinical course, and treatment of the disease.