转录因子LMO2与LYL1在髓系白血病细胞的异常表达与相互作用

Abnormal expression of transcription factors LYL1 and LMO2 and interaction between them in myeloid leukemia

目的探讨转录因子LMO2与LYL1在髓系白血病细胞的表达、相互作用及意义。方法荧光实时定量聚合酶链反应、基因转染与免疫共沉淀实验等。结果LMO2在51．1％的未缓解急性髓系白血病（AML）患者表达增强，LYL1在62．2％的AML患者表达增强，二者共同高表达的患者比例为31．1％，表达水平有正相关性。基因转染实验显示LMO2与LYL1的表达相互激活。应用免疫共沉淀证明髓系白血病细胞中LMO2-LYL1复合物的存在。结论LMO2与LYIL1在白血病细胞的表达异常和相互作用可能是引起髓系造血细胞增殖分化异常的重要因素。

Objective To explore the expression of the transcription factors LMO2 and LYL1 and the interaction between these 2 factors in myeloid leukemia cells and to analyze the significance thereof in leukemogenesis. Methods Samples of peripheral blood and bone marrow were collected form 51 AML patties, and 5 normal bone marrow donors to isolate mononuclear cells （ MNCs ） with high percentage of CD34 （ ＋ ） cells. Western blotting （WB） was used to detect the protein expression of LMO2 and LYL1 in the cells. Human myeloid leukemia cells of the line K562 were cultured and transfected with pcDNA3-LMO2, plasmid containing LMO2, peDNA3-LYL1, plasmid containing LYL1, or pcDNA-GFP, blank plasmid containing green fluorescent protein. RT-PCR was used to detect the mRNA expression of LMO2 and LYL1. Co-immnnoprecipitation （co-IP） and WB were used to detect the binding protein of LMO2 and LYL1. Results The MNCs of 51.1% of the patients with acute myeloblastic leukemia （AML） without remission expressed higher levels of LMO2, the MNCs of 62.2% of the AML patients expressed higher levels of LYL1, and the MNCs of 31.1% of those expressed both. The K562 cells transfected with pcDNA3-LMO2 showed higher mRNA and protein expression levels of both LMO2 and LYL1, and the K562 ceils transfected with pcDNA3-LYL1 showed higher mRNA and protein expression levels of both LYL1 and LMO2 too, as indicated by RT-PCR and WB, which suggested that the expression of LMO2 and the expression of LYL1 stimulated each other in the myeloid leukemia cells. Co-IP assay detected the presence of LMO2-LYLI complex in those cells. Conclusion The abnormal expression and protein interaction of LMO2 and LYL1 may play a role in the abnormal proliferation and differentiation of myeloid hematopoietic celts.