Iron Oxide Nanoparticles Combined with Cytosine Arabinoside Show Anti-Leukemia Stem Cell Effects on Acute Myeloid Leukemia by Regulating Reactive Oxygen Species

Abstract

Jun Dou,1,* Luoyang Li,1,* Mei Guo,1,* Feng Mei,1 Danfeng Zheng,1 Hui Xu,1 Rui Xue,1 Xueyang Bao,1 Fengshu Zhao,1 Yu Zhang2 1Department of Pathogenic Biology and Immunology, Medical College, Southeast University, Nanjing, 210009, People’s Republic of China; 2State Key Laboratory of Bioelectronics, Jiangsu Key Laboratory for Biomaterials and Devices, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210009, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jun DouDepartment of Pathogenic Biology and Immunology, Medical School, Southeast University, Nanjing, 210009, People’s Republic of ChinaEmail [email protected] ZhangSchool of Biological Science and Medical Engineering, Southeast University, Nanjing, 210009, People’s Republic of ChinaEmail [email protected] and Aim: Acute myeloid leukemia (AML), initiated and maintained by leukemia stem cells (LSCs), is often relapsed or refractory to therapy. The present study aimed at assessing the effects of nanozyme-like Fe3O4 nanoparticles (IONPs) combined with cytosine arabinoside (Ara-C) on LSCs in vitro and in vivo.Methods: The CD34+CD38–LSCs, isolated from human AML cell line KG1a by a magnetic activated cell sorting method, were treated with Ara-C, IONPs, and Ara-C+ IONPs respectively in vitro. The cellular proliferation, apoptosis, reactive oxygen species (ROS), and the related molecular expression levels in LSCs were analyzed using flow cytometry, RT-qPCR, and Western blot. The nonobese diabetic/severe combined immune deficiency mice were transplanted with LSCs or non-LSCs via tail vein, and then the mice were treated with Ara-C, IONPs and IONPs plus Ara-C, respectively. The therapeutic effects on the AML bearing mice were further evaluated.Results: LSCs indicated stronger cellular proliferation, more clone formation, and more robust resistance to Ara-C than non-LSCs. Compared with LSCs treated with Ara-C alone, LSCs treated with IONPs plus Ara-C showed a significant increase in apoptosis and ROS levels that might be regulated by nanozyme-like IONPs via improving the expression of pro-oxidation molecule gp91-phox but decreasing the expression of antioxidation molecule superoxide dismutase 1. The in vivo results suggested that, compared with the AML bearing mice treated with Ara-C alone, the mice treated with IONPs plus Ara-C markedly reduced the abnormal leukocyte numbers in peripheral blood and bone marrow and significantly extended the survival of AML bearing mice.Conclusion: IONPs combined with Ara-C showed the effectiveness on reducing AML burden in the mice engrafted with LSCs and extending mouse survival by increasing LSC’s ROS level to induce LSC apoptosis. Our findings suggest that targeting LSCs could control the AML relapse by using IONPs plus Ara-C.Keywords: acute myeloid leukemia, leukemia stem cells, Fe3O4 nanoparticles, cytosine arabinoside, reactive oxygen species

Keywords

• acute myeloid leukemia
• leukemia stem cells
• fe3o4 nanoparticles
• cytosine arabinoside
• reactive oxygen species