Goz B, Orr C, Wharton W
J Natl Cancer Inst. 1980 Jun;64(6):1355-61. doi: 10.1093/jnci/64.6.1355.
The main objective of these experiments was the further examination of whether the induction of alkaline phosphatase activity in HeLa cells by 5-iodo-2'-deoxyuridine (IdUrd) depends on the incorporation of IdUrd into DNA. Thymidine (dThd), deoxycytidine (dCyd), cytidine, and beta-cytosine arabinoside (Ara-C) inhibited a dose-dependent manner the induction of alkaline phosphatase activity by IdUrd in HeLa cells, and 5-iodo-2'-deoxycytidine induced activity in a dose-dependent manner at concentrations similar to those of IdUrd. Three of these compounds, dThd, dCyd, and Ara-C, were studied with regard to degree of inhibition of induction and IdUrd incorporation into DNA. Although the various doses of these three compounds decreased the incorporation of IdUrd into DNA, there was no apparent linear correlation between the extent of inhibition of IdUrd incorporation and the degree of inhibition of the induction of alkaline phosphatase activity. dCyd also inhibited a dose-dependent manner the induction of alkaline phosphatase by hydrocortisone, sodium butyrate, and choline chloridee. These results, although not unequivocal, support the idea that IdUrd induction of alkaline phosphatase activity in HeLa cells does not require IdUrd incorporation into DNA. The dCyd altered the thermostability for alkaline phosphatase activity from control or IdUrd-treated cells, and for controls cells the change in thermostability occurred without a change in the enzyme specific activity.
这些实验的主要目的是进一步研究5-碘-2'-脱氧尿苷（IdUrd）诱导HeLa细胞碱性磷酸酶活性是否依赖于IdUrd掺入DNA。胸腺嘧啶核苷（dThd）、脱氧胞苷（dCyd）、胞苷和β-阿拉伯糖胞苷（Ara-C）以剂量依赖的方式抑制IdUrd在HeLa细胞中诱导碱性磷酸酶活性，并且5-碘-2'-脱氧胞苷在与IdUrd相似的浓度下以剂量依赖的方式诱导活性。研究了其中三种化合物dThd、dCyd和Ara-C对诱导抑制程度和IdUrd掺入DNA的影响。尽管这三种化合物的不同剂量均降低了IdUrd掺入DNA的量，但IdUrd掺入的抑制程度与碱性磷酸酶活性诱导的抑制程度之间没有明显的线性相关性。dCyd还以剂量依赖的方式抑制氢化可的松、丁酸钠和氯化胆碱诱导的碱性磷酸酶。这些结果虽然不明确，但支持了IdUrd诱导HeLa细胞碱性磷酸酶活性不需要IdUrd掺入DNA的观点。dCyd改变了对照或IdUrd处理细胞碱性磷酸酶活性的热稳定性，对于对照细胞，热稳定性的变化发生在酶比活性无变化的情况下。
