Ostrem V K, Lau W F, Lee S H, Perlman K, Prahl J, Schnoes H K, DeLuca H F
Department of Biochemistry, University of Wisconsin-Madison 53706.
J Biol Chem. 1987 Oct 15;262(29):14164-71.
1,25-Dihydroxyvitamin D3, the hormonal form of vitamin D, induces differentiation of HL-60 human promyelocytes into monocyte-like cells in vitro. We assessed the relative activity of 30 analogs of 1,25-dihydroxyvitamin D3 in inducing development of monocytic markers in HL-60 cells. The three differentiation markers assayed were nonspecific acid esterase activity, nitro blue tetrazolium reducing activity, and phagocytic capacity. Of the known metabolites of vitamin D, 1,25-dihydroxyvitamin D3 is the most active; 50% of the cells exhibit the mature phenotype following a 4-day treatment with 10(-8) M 1,25-dihydroxyvitamin D3. Removal of either the C-1 or C-25-hydroxyl group reduces activity by 2 orders of magnitude, while epimerization of the 1 alpha- to 1 beta-hydroxyl group virtually abolishes activity. Elongation of the steroidal side chain of 1,25-dihydroxyvitamin D3 by addition of one carbon at C-24 or C-26 improves the potency by an order of magnitude. Truncation of the steroidal side chain leads to a 10-fold reduction in activity for each carbon removed. Elimination of the C-26 and C-27 methyl groups reduces activity 100-fold. Analogs with short aliphatic side chains as 1 alpha-hydroxyhomo- and bishomopregnacholecalciferol have surprisingly high activity, being only 20-fold less potent than the natural hormone. The activity of most analogs in the HL-60 system parallels their known relative affinities for the well characterized 1,25-dihydroxyvitamin D3 receptor in chick intestine, providing further evidence that this function of 1,25-dihydroxyvitamin D3 is receptor mediated.
1,25 - 二羟基维生素D3是维生素D的激素形式，可在体外诱导HL - 60人早幼粒细胞分化为单核细胞样细胞。我们评估了30种1,25 - 二羟基维生素D3类似物在诱导HL - 60细胞中单核细胞标志物发育方面的相对活性。所检测的三种分化标志物为非特异性酸性酯酶活性、硝基蓝四唑还原活性和吞噬能力。在维生素D的已知代谢产物中，1,25 - 二羟基维生素D3活性最强；用10(-8)M 1,25 - 二羟基维生素D3处理4天后，50%的细胞呈现成熟表型。去除C - 1或C - 25羟基会使活性降低2个数量级，而1α - 羟基向1β - 羟基的差向异构化实际上会消除活性。通过在C - 24或C - 26处添加一个碳原子来延长1,25 - 二羟基维生素D3的甾体侧链，可使效力提高一个数量级。甾体侧链的截短会导致每去除一个碳原子活性降低10倍。去除C - 26和C - 27甲基会使活性降低100倍。具有短脂肪族侧链的类似物，如1α - 羟基高 - 和双高 - 孕甾烷醇，具有惊人的高活性，其效力仅比天然激素低20倍。大多数类似物在HL - 60系统中的活性与它们已知的对鸡肠道中特征明确的1,25 - 二羟基维生素D3受体的相对亲和力平行，这进一步证明了1,25 - 二羟基维生素D3的这种功能是由受体介导的。
