Acute myeloid leukemia (AML) is a malignant clonal disease derived from hematopoietic stem/progenitor cell. Leukemia blasts cause extensive hypoxia of bone marrow (BM), which lead to disorder and remodeling of BM niche, thereby becoming "leukemic niche" to support the development and drug-resistance of AML as well as the maintenance of normal hematopoietic stem cells. In this study, the biological characteristics (such as self-renewal, apoptosis, migration, autocrine) and function (vascularization) of mesenchymal stem cells (MSCs) and human umbilical artery endothelial cells (HUAECs) that make up BM arteriolar niche in simulated hypoxia AML context were investigated. It was found that moderate hypoxia enhanced the viability of the arteriolar niche cells, but severe hypoxia of AML BM resulted in the damage of arteriolar niche cells and the disorder of vascular cytokines C-X-C motif chemokine ligand 6 (CXCL6). The dynamic changes of CXCL6 in the system as well as its anti-apoptotic and promoting angiogenic effects suggested that CXCL6 played an important role in the remodeling of BM arteriolar niche in AML. Taking advantage of CXCL6 can save the damaged MSCs and HUAECs, which is the hope of rescuing arteriolar niche. It is suggested that CXCL6 may be an assistant strategy for microenvironment targeted therapy of AML.
Keywords: CXCL6; Hypoxia; acute myeloid leukemia; arteriolar niche; endothelial progenitor cells; mesenchymal stem cells.