Xu H M, Tepper C G, Jones J B, Fernandez C E, Studzinski G P
Department of Laboratory Medicine and Pathology, UMDNJ-New Jersey Medical School, Newark 07103.
Exp Cell Res. 1993 Dec;209(2):367-74. doi: 10.1006/excr.1993.1322.
Exposure of myeloid leukemia cells to analogs of vitamin D results in monocytic-like maturation of several variants of these cells. We report here that brief treatment of HL60 cells with differentiation-inducing concentrations of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) makes these cells resistant to cell death by apoptosis. Resistance was studied by using the calcium inophore A23187 and the cancer chemotherapeutic drugs 1-beta-D-arabinocytosine and etoposide. Apoptosis was detected by the characteristic morphology under light microscopic examination, presence of DNA "ladders" on agarose gel electrophoresis, DNA fragmentation by filter elution assay, and the "apoptotic index" obtained by comparison of damage to mitochondrial and nuclear genes on Southern blots. The protective effect of 1,25(OH)2D3 treatment was apparent before the phenotypic evidence of differentiation and before altered traverse of the cell cycle could be detected. Northern and Western blot analysis showed that the expression of bcl-2 proto-oncogene was rapidly reduced by 1,25(OH)2D3, which excludes the involvement of this gene in the protective effect. The rapidity of the protective effect of 1,25(OH)2D3 is consistent with the hypothesis that the activation of the monocytic differentiation program is sufficient to interfere with programs that lead to cell death by apoptosis.
髓系白血病细胞暴露于维生素D类似物会导致这些细胞的几种变体出现单核细胞样成熟。我们在此报告，用诱导分化浓度的1,25 - 二羟基维生素D3（1,25(OH)2D3）对HL60细胞进行短暂处理，可使这些细胞对凋亡引起的细胞死亡产生抗性。通过使用钙离子载体A23187以及癌症化疗药物1 - β - D - 阿拉伯糖胞苷和依托泊苷来研究这种抗性。通过光学显微镜检查下的特征性形态、琼脂糖凝胶电泳上DNA“梯形条带”的存在、滤膜洗脱法检测的DNA片段化以及通过比较Southern印迹中线粒体和核基因损伤获得的“凋亡指数”来检测凋亡。1,25(OH)2D3处理的保护作用在分化的表型证据出现之前以及在检测到细胞周期改变之前就已明显。Northern和Western印迹分析表明，1,25(OH)2D3可使bcl - 2原癌基因的表达迅速降低，这排除了该基因参与保护作用的可能性。1,25(OH)2D3保护作用的快速性与单核细胞分化程序的激活足以干扰导致细胞凋亡死亡的程序这一假设一致。
