Inaba M, Morii H, DeLuca H F
Second Department of Internal Medicine, Osaka City University Medical School, Osaka, Japan.
Contrib Nephrol. 1991;91:102-8. doi: 10.1159/000420164.
Two types of HL-60 cells, 1,25-(OH)2D3-responsive ATCC HL-60 cells and 1,25-(OH)2D3-resistant LG HL-60 cells were used. Despite the presence of enough amounts of normal 1,25-(OH)2D3 receptors, only 22% of LG cells matured after a 4-day treatment with 10(-7) M 1,25-(OH)2D3, while 80% of ATCC cells differentiated. However, 1,25-(OH)2D3 inhibited the proliferation of LG cells to the same degree as that of ATCC cells. 1,25-(OH)2D3 also induced (1) the ability to metabolize 1,25-(OH)2D3 to 1,24,25-(OH)3D3, and (2) up-regulation of the 1,25-(OH)2D3 receptor in LG as well as ATCC cells. Furthermore, the proportion of mature LG cells was 78% after treatment with 10(-7) M 1,25-(OH)2D3 for the first 48 h and 10(-7) M dbcAMP for the second 48 h, which was greater than that when treated only with 10(-7) M dbcAMP for the second 48 h (24.2%). These results indicate that 1,25-(OH)2D3 receptor complexes function normally in LG cells at commitment step in cell differentiation. ATCC cells had a serine proteinase to destroy specific 1,25-(OH)2D3-binding activity of the unoccupied receptor and digest 53-kD receptor to a small fragment with a MW of 16.3 kD, while not affecting the level of the specific binding of the occupied receptor. Other cells, such as murine leukemia cells, M1, and human chronic myeloid leukemia cells, the differentiation of which is induced by 1,25-(OH)2D3, seemed to have the same type of proteinase, suggesting the physiological significance of this proteinase in 1,25-(OH)2D3-induced cell differentiation.
使用了两种类型的HL-60细胞，即对1,25-(OH)₂D₃有反应的美国典型培养物保藏中心（ATCC）HL-60细胞和对1,25-(OH)₂D₃耐药的LG HL-60细胞。尽管存在足够数量的正常1,25-(OH)₂D₃受体，但在用10⁻⁷M 1,25-(OH)₂D₃处理4天后，只有22%的LG细胞成熟，而80%的ATCC细胞发生了分化。然而，1,25-(OH)₂D₃对LG细胞增殖的抑制程度与对ATCC细胞的抑制程度相同。1,25-(OH)₂D₃还诱导了（1）将1,25-(OH)₂D₃代谢为1,24,25-(OH)₃D₃的能力，以及（2）LG细胞和ATCC细胞中1,25-(OH)₂D₃受体的上调。此外，在用10⁻⁷M 1,25-(OH)₂D₃处理前48小时和用10⁻⁷M双丁酰环磷腺苷（dbcAMP）处理后48小时后，成熟LG细胞的比例为78%，这一比例高于仅在第二个48小时用10⁻⁷M dbcAMP处理时的比例（24.2%）。这些结果表明，1,25-(OH)₂D₃受体复合物在LG细胞的细胞分化起始步骤中正常发挥作用。ATCC细胞有一种丝氨酸蛋白酶，可破坏未占据受体的特异性1,25-(OH)₂D₃结合活性，并将53-kD受体消化成一个分子量为16.3 kD的小片段，而不影响占据受体的特异性结合水平。其他细胞，如小鼠白血病细胞M1和人慢性髓性白血病细胞，其分化由1,25-(OH)₂D₃诱导，似乎也有相同类型的蛋白酶，这表明这种蛋白酶在1,25-(OH)₂D₃诱导的细胞分化中具有生理意义。
