Analysis of Expression of LAT1 in Childhood Leukemia and Effect of Inhibitors on Proliferation Inhibition

采用Western blotting法、荧光标记抗体法和RT-PCR法检测了儿童白血病细胞株和缓解期儿童白血病细胞LAT1的表达，并用四甲基偶氮唑盐比色法检测了LAT1抑制剂BCH对白血病细胞百分率的影响。LAT1在不同生物学性质的白血病细胞系和不同预后、不同细胞类型的骨髓白血病细胞中的表达无明显差异。缓解期部分骨髓细胞也观察到LAT1的表达，BCH可通过剂量依赖的方式降低白血病细胞系的易感性。但随着剂量的增加，易感性减少率下降，BCH浓度超过300微米不能获得LC_(50)&gt；。此外，LAT1在缓解期表达于骨髓细胞。由于已知LAT1表达于外周血白细胞和骨髓，因此LAT1抑制剂可抑制正常骨髓细胞的增殖。其他具有更高选择性的抑制剂可能能够更有效地减少倾向性。由于目前已有的具有这种特性的缓蚀剂是不溶于水的，因此需要寻找新的缓蚀剂。抑制剂对造血干细胞的作用也需要在进一步的研究中进行测试。

Expression of LAT1 was investigated for childhood leukemia cell lines and bone marrow cells from children with various kinds of leukemia at the diagnosis and during remission by Western blotting method, fluorescence-labeled antibody method and RT-PCR.Effect of BCH, one of inhibitors of LAT1, on cell liability was also investigated using MTT assay.Expression of LAT1 was found for all cell lines and bone marrow cells at diagnosis with all kinds of employed methods. Difference of expression of LAT1 was not observed among investigate leukemic cell lines with various biological natures and bone marrow leukemic cells with different prognoses and different cell types. Expression of LAT1 was also observed some of bone marrow cells during the remission phase.BCH could reduce liability of leukemic cell lines by dose-dependent manner. However, rate of reduction of liability decreased during increasing dose and LC_<50> could not be obtained by the BCH concentration of above 300 microM.Above result indicates necessity of stronger inhibitors to treat leukemia. Moreover, LAT1 was expressed on bone marrow cells during the remission. Since LAT1 is known to express on peripheral leukocytes and bone marrow, proliferation of normal bone marrow cells might be inhibited with LAT1 inhibitor. Other inhibitors with higher selectivity may be able to decrease liability more efficiently. Since currently available inhibitors with such characteristics are water insoluble, new inhibitors should be searched. Effects of inhibitors on hematopoietic stem cells are also needed to be tested in further studies.