Chen S F, Cleaveland J S, Hollmann A B, Wiemann M C, Parks R E, Stoeckler J D
Cancer Res. 1986 Jul;46(7):3449-55.
The rate of nucleoside transport decreased profoundly in human promyelocytic leukemia HL-60 cells after myeloid differentiation was induced by 5-6 days of exposure to 0.8% N,N-dimethylformamide (DMF). The facilitated diffusion of 100 microM radiolabeled adenosine and 2'-deoxyadenosine, measured by rapid transport assays, decreased 10- to 20-fold. The transport of 2 microM coformycin or 2'-deoxycoformycin, which is mediated by the same mechanism and was monitored by the adenosine deaminase titration assay, decreased 29-fold. The reduction in nucleoside transport capacity after DMF treatment was confirmed by a 19-fold decrease in the number of specific binding sites per cell (from 24-30 X 10(4) to 1.2-1.7 X 10(4)) for [3H]-6-p-nitrobenzylthioinosine, a nucleoside transport inhibitor. The binding affinity of 6-p-nitrobenzylthioinosine was not altered significantly and nucleoside transport remained sensitive to the transport inhibitors, 6-p-nitrobenzylthioinosine, dipyridamole, and dilazep after DMF-induced maturation. Time-dependence studies showed that the rate of 100 microM deoxyadenosine transport was unchanged for the first 24 h of exposure to DMF but fell to about 36% of control rates at 24-26 h and then gradually decreased further to about 4-5% of control rates after 5-6 days. In contrast, transport rates of the purine bases were reduced only 2- to 3-fold in HL-60 cells after 5 days of DMF treatment. The rates of adenosine and deoxyadenosine transport were unchanged or reduced by no more than 2-fold after 5-6 days of exposure to 0.8% DMF in the following human tumor cell lines that are not inducible with DMF: ARH-77 (multiple myeloma), KG-1 (acute myelogenous), and K-562 (chronic myelogenous). Thus, changes in nucleoside transport may serve as an early, membrane-associated marker of differentiation of the HL-60 cell line.
在人早幼粒细胞白血病HL-60细胞中，经0.8% N，N-二甲基甲酰胺（DMF）处理5 - 6天诱导髓系分化后，核苷转运速率显著降低。通过快速转运试验测定，100微摩尔放射性标记的腺苷和2'-脱氧腺苷的易化扩散降低了10至20倍。由相同机制介导并通过腺苷脱氨酶滴定试验监测的2微摩尔助间型霉素或2'-脱氧助间型霉素的转运降低了29倍。DMF处理后核苷转运能力的降低通过每个细胞中[3H]-6-对硝基苄硫基肌苷（一种核苷转运抑制剂）特异性结合位点数量减少19倍得到证实（从24 - 30×10⁴降至1.2 - 1.7×10⁴）。DMF诱导成熟后，6-对硝基苄硫基肌苷的结合亲和力没有显著改变，并且核苷转运对转运抑制剂6-对硝基苄硫基肌苷、双嘧达莫和地拉齐普仍然敏感。时间依赖性研究表明，在暴露于DMF的最初24小时内，100微摩尔脱氧腺苷的转运速率没有变化，但在24 - 26小时降至对照速率的约36%，然后在5 - 6天后进一步逐渐降至对照速率的约4 - 5%。相比之下，在DMF处理5天后，HL-60细胞中嘌呤碱的转运速率仅降低了2至3倍。在以下不能被DMF诱导的人肿瘤细胞系中，暴露于0.8% DMF 5 - 6天后，腺苷和脱氧腺苷的转运速率没有变化或降低不超过2倍：ARH-77（多发性骨髓瘤）、KG-1（急性髓性白血病）和K-562（慢性髓性白血病）。因此，核苷转运的变化可能作为HL-60细胞系分化的一种早期的、与膜相关的标志物。
