Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland; Faculty of Chemistry, University of Warsaw, L. Pasteura 1, 02-093 Warsaw, Poland.
Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland; Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, L. Pasteura 5, 02-093 Warsaw, Poland; College of Inter-Faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
Bioorg Med Chem. 2020 Jul 1;28(13):115523. doi: 10.1016/j.bmc.2020.115523. Epub 2020 Apr 25.
Eukaryotic translation initiation factor 4E (eIF4E) is overexpressed in many cancers deregulating translational control of the cell cycle. mRNA 5' cap analogs targeting eIF4E are small molecules with the potential to counteract elevated levels of eIF4E in cancer cells. However, the practical utility of typical cap analogs is limited because of their reduced cell membrane permeability. Transforming the active analogs into their pronucleotide derivatives is a promising approach to overcome this obstacle. 7-Benzylguanosine monophosphate (bnGMP) is a cap analog that has been successfully transformed into a cell-penetrating pronucleotide by conjugation of the phosphate moiety with tryptamine. In this work, we explored whether a similar strategy is applicable to other cap analogs, particularly phosphate-modified 7-methylguanine nucleotides. We report the synthesis of six new tryptamine conjugates containing N-methylguanosine mono- and diphosphate and their analogs modified with thiophosphate moiety. These new potential pronucleotides and the expected products of their activation were characterized by biophysical and biochemical methods to determine their affinity towards eIF4E, their ability to inhibit translation in vitro, their susceptibility to enzymatic degradation and their turnover in cell extract. The results suggest that compounds containing the thiophosphate moiety may act as pronucleotides that release low but sustainable concentrations of 7-methylguanosine 5'-phosphorothioate (mGMPS), which is a translation inhibitor with in vitro potency higher than bnGMP.
真核翻译起始因子 4E（eIF4E）在许多癌症中过度表达，导致细胞周期的翻译调控失控。针对 eIF4E 的 mRNA 5'帽类似物是小分子，具有抵消癌细胞中 eIF4E 水平升高的潜力。然而，由于其细胞膜通透性降低，典型帽类似物的实际应用受到限制。将活性类似物转化为其前核苷衍生物是克服这一障碍的一种有前途的方法。7-苄基鸟苷单磷酸（bnGMP）是一种帽类似物，已通过将磷酸部分与色胺缀合成功转化为穿透细胞膜的前核苷。在这项工作中，我们探讨了这种类似的策略是否适用于其他帽类似物，特别是磷酸化修饰的 7-甲基鸟苷核苷酸。我们报告了六种新的色胺缀合物的合成，其中包含 N-甲基鸟苷单磷酸和二磷酸及其类似物，并用硫代磷酸部分修饰。通过生物物理和生化方法对这些新的潜在前核苷及其激活产物进行了表征，以确定它们与 eIF4E 的亲和力、体外抑制翻译的能力、对酶降解的敏感性以及在细胞提取物中的周转率。结果表明，含有硫代磷酸部分的化合物可能作为前核苷发挥作用，释放低但可持续的浓度 7-甲基鸟苷 5'-硫代磷酸（mGMPS），这是一种体外效力高于 bnGMP 的翻译抑制剂。
