Olive P L, Chaplin D J
Int J Radiat Oncol Biol Phys. 1986 Jul;12(7):1247-50. doi: 10.1016/0360-3016(86)90269-5.
Fluorescent nitroheterocycles such as AF-2 may be useful in identifying hypoxic cells in tumors. Since binding is dependent on rate of drug metabolism (nitroreduction) as well as cellular oxygen content, flow cytometric analysis of cells from tumors and spheroids was used to quantify AF-2 binding, and differential pulse polarography was used to measure reduction of AF-2 by several mammalian cell lines, spheroids and tumor cells. Hypoxic V79 spheroid cells and Lewis lung tumor cells bound 20 times more AF-2 than oxic cells, and binding proceeded with first order kinetics. Nitroreductase activity varied about tenfold among different tumor cells. As expected, the rate of binding of AF-2 correlated well with the rate of nitroreduction. Oral injection of AF-2 (5 mg) was the most successful method of administration to tumor-bearing mice. In mice injected with both AF-2 and Hoechst 33342 (which stains well-perfused cells), SCCVII tumor cells which contained the most Hoechst contained the least AF-2. Although minimal toxicity by AF-2 was observed in these tumors, binding of AF-2 was barely sufficient for detection using flow cytometry.
诸如AF-2之类的荧光硝基杂环化合物可能有助于识别肿瘤中的缺氧细胞。由于结合取决于药物代谢速率（硝基还原）以及细胞含氧量，因此利用流式细胞术分析肿瘤和球体中的细胞来量化AF-2的结合情况，并采用微分脉冲极谱法来测定几种哺乳动物细胞系、球体和肿瘤细胞对AF-2的还原作用。缺氧的V79球体细胞和刘易斯肺癌细胞对AF-2的结合量比有氧细胞多20倍，且结合过程符合一级动力学。不同肿瘤细胞中的硝基还原酶活性相差约10倍。正如预期的那样，AF-2的结合速率与硝基还原速率密切相关。口服注射AF-2（5毫克）是给荷瘤小鼠给药的最成功方法。在同时注射AF-2和Hoechst 33342（用于标记灌注良好的细胞）的小鼠中，Hoechst含量最高的SCCVII肿瘤细胞中AF-2含量最少。尽管在这些肿瘤中观察到AF-2的毒性极小，但AF-2的结合量几乎不足以通过流式细胞术进行检测。
