ABSTRACT: To investigate the pathological effect of miR-126 on the progression of acute myeloid leukemia (AML) induced by AML1-ETO9a (AE9a), we conducted a series of mouse bone marrow transplantation (BMT) assays with the following groups: AE9a (primary donor cells were wild-type mouse bone marrow progenitor (i.e., lineage negative; Lin-) cells retrovirally transduced with MSCV-PIG-AE9a), AE9a+miR-126 (primary donor cells were wild-type mouse bone marrow progenitor (i.e., Lin-) cells retrovirally transduced with MSCV-PIG-AE9a-miR-126), and miR-126KO+AE9a (primary donor cells were miR-126 knockout mouse bone marrow progenitor (i.e., Lin-) cells retrovirally transduced with MSCV-PIG-AE9a), along with a control group (primary donor cells were wild-type mouse bone marrow progenitor (i.e., Lin-) cells retrovirally transduced with MSCV-PIG empty vector). The control group was only used in the primary and secondary BMT assays, whereas the three leukemic groups including AE9a, AE9a+miR-126 and miR-126KO+AE9a were used in four passages (i.e., primary, secondary, tertiary and quaternary) of BMT assays. Then, gene expression profiling was conducted with bone marrow samples collected from different groups to decipher the molecular mechanisms underlying miR-126 effects on leukemia initiation and progression and maintenance and self-renewal of leukemia stem/initiating cells. A total of 39 mouse bone marrow samples including 36 mouse AML samples with AE9a, AE9a+miR-126, and miR-126KO+AE9a collected from the 1st, 2nd, 3rd and 4th passages of BMT recipient mice (3 mice for each group in each passage), along with 3 normal controls from the 1st passage of BMT, were analyzed by use of Affymetrix GeneChip Mouse Gene 2.0 ST Array (Affymetirx, Santa Clara, CA). For each sample, the CD45.1+ cells (i.e., transplanted donor cells) were sorted with flow cytometry from whole BM cells collected from BMT recipient mice at the end stage. Then total RNA was isolated by use of miRNeasy extraction kit (Qiagen, Valencia, CA).
