ABSTRACT
Transient kinetic studies with human immunodeficiency virus (HIV) type 1 reverse transcriptase suggest that nucleotide analogs containing the 2',3'-didehydro-2',3'-dideoxy ribose ring structure present in D4T (stavudine) triphosphate are among the most effective alternative substrates. For unclear reasons, however, the corresponding purine nucleoside, 2',3'-didehydro-2',3'-dideoxyguanosine (D4G), was found to be inactive in cell culture. We have found that the previously reported lack of activity of D4G is primarily due to solution instability, and in this report we describe a novel use of a guanosine prodrug approach to stabilize the nucleoside. D4G was modified at the 6 position of the purine ring to contain a cyclopropylamino group yielding the prodrug, cyclo-D4G. An evaluation of cyclo-D4G revealed that the prodrug possessed anti-HIV activity. In addition, cyclo-D4G had increased stability, lipophilicity, and solubility, as well as decreased toxicity relative to D4G, suggesting that further study is warranted.
摘要
对人类免疫缺陷病毒(HIV)1 型逆转录酶的瞬时动力学研究表明,D4T(司他夫定)三磷酸中含有 2',3'-二脱氢-2',3'-二脱氧核糖环结构的核苷酸类似物是最有效的替代底物之一。然而,由于不明原因,人们发现相应的嘌呤核苷--2',3'-双脱氢-2',3'-双脱氧鸟苷(D4G)在细胞培养中没有活性。我们发现,之前报道的 D4G 缺乏活性的主要原因是溶液的不稳定性,在本报告中,我们介绍了一种利用鸟苷原药稳定核苷的新方法。D4G 在嘌呤环的 6 位被修饰成含有环丙基氨基,从而产生了环-D4G 原药。对环-D4G 的评估显示,该原药具有抗艾滋病毒的活性。此外,与 D4G 相比,环-D4G 的稳定性、亲油性和可溶性都有所提高,毒性也有所降低,这表明有必要对其进行进一步研究。