三氧化二砷对转染表达两种早幼粒细胞性白血病融合蛋白的K562细 …

目的　探讨急性早幼粒细胞性白血病的特异融合蛋白PML RARα和PLZF RARα在三氧化二砷 (As2 O3 )效应中的可能作用。方法　应用逆病毒载体转染技术建立稳定表达PML RARα(KPML)、PLZF RARα(ΚPLZF)和空载体 (KV)的K5 6 2细胞克隆。通过活细胞计数、形态学观察、流式细胞仪检测细胞DNA含量和分化抗原。应用免疫荧光分析PML RARα蛋白的亚细胞分布。结果　 1 0μmol/LAs2 O3 不诱导KV 细胞凋亡和分化 ,但明显抑制其生长。在KPML和KPLZF细胞 ,As2 O3 也产生相似的生长抑制效应 ,但其效应强度明显增加。经 1 0 μmol/LAs2 O3 处理 3d时 ,KV、KPML和KPLZF的生长抑制率分别为 32 %± 3%、5 7%± 4%和 5 4%± 6 %。 1 0 μmol/L的全反式维甲酸也显示对KV 细胞克隆的生长抑制 ,但其效应明显低于As2 O3 。同时 ,全反式维甲酸的生长抑制效应在KPML的表现较KV 明显(P <0 .0 5 ) ,但在KV 和KPLZF之间差异无显著意义。此外 ,在 1 0 μmol/LAs2 O3 作用 2d时 ,KV 和KPML细胞内PML/PML RARα蛋白颗粒明显减少甚至消失。结论　PML RARα和PLZF RARα蛋白明显加强As2 O3 对K5 6 2细胞的生长抑制效应。

Effects of arsenic trioxide on K562 cells stably expressing two promyelocytic leukemia-specific fusion proteins

OBJECTIVE: To illustrate the possible roles of acute promyelocytic leukemia-specific chimeric proteins PML-RARalpha and PLZF-RARalpha in the effects of arsenic trioxide (As(2)O(3)). METHODS: K562 sublines stably expressing PML-RARalpha (K(PML() and PLZF-RARalpha (K(PLZF)) were established by retrovirus transfection with K(V) transfected empty vectors as controls. Effects of As(2)O(3) and all-trans retinoic acid (ATRA) on these sublines were analyzed through cell count, morphology, measurement of cellular DNA contents and differentiation antigens on flow cytometry. Subcellular distributions of PML-RARalpha proteins were observed with immunofluorescence. RESULTS: 1.0 micromol/L of As(2)O(3) did not induce cell apoptosis and differentiation, but it significantly inhibited the growth of K(V) sublines. As(2)O(3) showed the similar but more potent effects in K(PML) and K(PLZF) sublines. 1.0 micromol/L As(2)O(3) treatment for 3 days induced growth inhibition by 32% +/- 3%, 57% +/- 4% and 54% +/- 6%, respectively in K(V), K(PML) and K(PLZF) sublines. 1.0 micromol/L ATRA also exerted, to a less extent than As(2)O(3), growth-inhibitory effects in K(V) sublines, which became more obvious in K(PML) but not in K(PLZF) sublines. In addition, PML/PML-RARalpha proteins were decreased and even disappeared in K(V) and K(PML) sublines with the treatment of 1.0 micromol/L As(2)O(3) for 48 hours. CONCLUSION: PML-RARalpha and PLZF-RARalpha markedly enhance growth-inhibitory effects of As2)O3) on K562 cells.