Abnormal Ferroptosis in Myelodysplastic Syndrome.

Qi Lv,Lanzhu Yue,Chunyan Liu,Huaquan Wang,Shuwen Dong,Zonghong Shao,Huijuan Jiang,Haiyue Niu,Liyan Yang,Limin Xing,Jiaxi Liu

doi:10.3389/fonc.2020.01656

Abstract

BackgroundFerroptosis is a form of iron-dependent non-apoptotic cell death, with characteristics of loss of the activity of the lipid repair enzyme, glutathione (GSH) peroxidase 4 (GPX4), and accumulation of lethal reactive lipid oxygen species. The mechanism of ferroptosis in myelodysplastic syndrome (MDS) is unclear.MethodsCell viability assay, reactive oxygen species (ROS) assay, GSH assay, and GPX activity assay were performed to study the regulation of ferroptosis in MDS cells obtained from MDS patients, the iron overload model mice, and cell lines.ResultsThe growth-inhibitory effect of decitabine could be partially reversed by ferrostatin-1 and iron-chelating agent [desferrioxamine (DFO)] in MDS cell lines. Erastin could increase the cytotoxicity of decitabine on MDS cells. The level of GSH and the activity of GPX4 decreased, whereas the ROS level increased in MDS cells upon treatment with decitabine, which could be reversed by ferrostatin-1. The concentration of hemoglobin in peripheral blood of iron overload mice was negatively correlated with intracellular Fe2+ level and ferritin concentration. Iron overload (IO) led to decreased viability of bone marrow mononuclear cells (BMMNCs), which was negatively correlated with intracellular Fe2+ level. Ferrostatin-1 partially reversed the decline of cell viability in IO groups. The level of GSH and the activity of GPX4 decreased, whereas the ROS level increased in BMMNCs of IO mice. DFO could increase the level of GSH. Ferrostatin-1 and DFO could increase the GPX4 activity of BMMNCs in IO mice. Ferrostatin-1 could significantly reverse the growth-inhibitory effect of decitabine in MDS patients. Decitabine could significantly increase the ROS level in MDS groups, which could be inhibited by ferrostatin-1 or promoted by erastin. Ferrostatin-1 could significantly reverse the inhibitory effect of decitabine on GSH levels in MDS patients. Erastin combined with decitabine could further reduce the GSH level. Erastin could further decrease the activity of GPX4 compared with the decitabine group.ConclusionFerroptosis may account for the main mechanisms of how decitabine induced death of MDS cells. Decitabine-induced ROS raise leads to ferroptosis in MDS cells by decreasing GSH level and GPX4 activity.

Highlights

Cell death is a critical event in normal development, homeostasis, and prevention of cancer
The 6-carboxy2’,7’dichlorodihydrofluorescein diacetate (DCFH-DA) and Z-VAD-FMK were purchased from Beyotime Institute of Biotechnology (China); FeRhoNox-1 was purchased from GORYO Chemical (Japan); erastin was purchased from Selleck Chemical (United States); Roswell Park Memorial Institute 1640 (RPMI 1640) was purchased from Gibco (United States); deferoxamine mesylate was purchased from TargetMol (United States); fetal bovine serum (FBS) was purchased from Lonsera (Uruguay); Hank’s balanced salt solution (HBSS) was purchased from Macgene (China); phosphatebuffered saline (PBS); and lymphocyte separation medium were purchased from Solarbio (China); iron dextran was purchased from Pharmacosmos A/S (Denmark); and necrostatin-1 was purchased from Santa Cruz (United States)
To determine whether ferroptosis is triggered by decitabine in myelodysplastic syndrome (MDS) cells, two cell lines (SKM-1 and MUTZ-1) were treated with decitabine (0.125, 0.250, and 0.500 mM) and Fer-1 (0.2, 0.4, and 0.8 μM) for 24 or 48 h, respectively

Summary

Introduction

Cell death is a critical event in normal development, homeostasis, and prevention of cancer. It is tightly connected with other biological processes reflecting vital physiological and pathological changes in cells. The accidental cell death is triggered by severe physical, chemical, and mechanical insults and cannot be reversed by molecular perturbations, whereas regulated cell death is a programmed process that can be modulated pharmacologically and genetically and is controllable [1]. Critical signaling pathways have been identified for some of these regulated non-apoptotic forms of cell death, such as necroptosis, which is found to be induced by tumor necrosis factor, whereas many other cell death forms are still under extensive investigation [2]. The mechanism of ferroptosis in myelodysplastic syndrome (MDS) is unclear

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Conclusion