Myelofibrosis Models: Literature Review and Own Data

Abstract

Background & Aims. Chronic myeloproliferative disorders typically develop during a long latent period, and it complicates the study of the mechanism of its pathogenesis. Observations from the clinical practice should be confirmed by experiments. The mechanisms of oncological transformation related to mutations associated with chronic myeloproliferative diseases were confirmed in transgene animal models. Biological models permitted to determine a complex nature of myelofibrosis. However, studies of the cellular mechanisms of myelofibrosis require new models. This paper presents a review of published models of myeloproliferative disorders, mainly, primary myelofibrosis, and results of studies of a new cell line with expression of JAK2 V617F. The aim of this study is to create a new cell line with expression of transforming JAK2 V617F mutation in acute monocytic leukemia THP-1 cells. Methods. Transgenic cell lines were created on the basis of monocytic leukemia THP-1 cell line that can differentiate into macrophages. Direct mutagenesis was used to cause V617F mutation. Two cell lines were created: one with JAK2 expression with V617F mutation, the other with wild type JAK2. Results. Both transgenic lines were characterized by increased JAK2 expression as compared to non-modified cells. In routine cultivation, transgenic THP-1 cells retained the morphology of monocytes. After treatment with phorbol ester, THP-1 differentiated into macrophages and become adherent to culture plastic. Adherent cells demonstrated the variety of shapes: some of them were spherical, the other ones had pseudopodia. No significant differences in viability of cells were observed. However, macrophages expressing mutant JAK2 and overexpressing the wild type JAK2 demonstrated a tendency to decreased amount unlivable cells during cultivation. Conclusion. The obtained cell model can be used for estimating the influence of JAK2 V617F mutation on pro- and antifibrotic potential of macrophages that can help to investigate the pathogenetic role of macrophages in myelofibrosis development. In addition, this model can help to develop novel methods of therapy and diagnostics of primary and secondary myelofibrosis.