Hazav P, Shany S, Moran A, Levy R
Unit of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel.
Cancer Res. 1989 Jan 1;49(1):72-5.
Besides its effect in inhibiting proliferation and inducing differentiation of HL-60 to monocyte-like cells, 1,25-dihydroxyvitamin D3 also causes a rise in intracellular pH (pHi) from 7.17 +/- 0.02 to 7.3 +/- 0.05, as measured by the fluorescence of 2',7'-bis(carboxyethyl)-5-(6)-carboxy-fluorescein. The effect of 1,25-dihydroxyvitamin D3 on pHi is dose dependent in a parallel manner to its effect on the proliferation and differentiation processes. The elevation of pHi by 1,25-dihydroxyvitamin D3 is gradual but precedes the differentiation process. A significant increase in pHi was obtained after 16 h of incubation with the hormone and reached its maximum level after 48 h. pHi then dropped back to its initial level, which is also similar to that of peripheral normal blood monocytes. A rise in pHi was not observed during incubation of HL-60 cells with 24,25-dihydroxyvitamin D3, a metabolite which does not promote their differentiation. In contrast, other agents such as phorbol 12-myristate 13-acetate known to induce differentiation in this cell line do cause an increase in pHi. Moreover, alkalinization of HL-60 cells by NH4Cl causes induction of differentiation to monocytes. The results suggest that a rise in pHi plays a role in regulating the molecular mechanism of the inhibition of proliferation and the induction of differentiation in HL-60 cells.
除了具有抑制HL-60细胞增殖并诱导其向单核细胞样细胞分化的作用外，1,25-二羟基维生素D3还会使细胞内pH值（pHi）从7.17±0.02升高至7.3±0.05，这是通过2',7'-双（羧乙基）-5-（6）-羧基荧光素的荧光进行测量的。1,25-二羟基维生素D3对pHi的影响与其对增殖和分化过程的影响呈平行的剂量依赖性。1,25-二羟基维生素D3引起的pHi升高是渐进的，但先于分化过程。与该激素孵育16小时后pHi显著升高，并在48小时后达到最高水平。然后pHi又降至其初始水平，这也与外周正常血液单核细胞的水平相似。在用不促进HL-60细胞分化的代谢物24,25-二羟基维生素D3孵育HL-60细胞的过程中，未观察到pHi升高。相反，其他已知可诱导该细胞系分化的试剂，如佛波醇12-肉豆蔻酸酯13-乙酸酯，确实会导致pHi升高。此外，氯化铵使HL-60细胞碱化会导致其向单核细胞分化。结果表明，pHi升高在调节HL-60细胞增殖抑制和分化诱导的分子机制中起作用。
