Gasparini A, Giovine M, Damonte G, Tonetti M, Grandi T, Mazzei M, Balbi A, Silvestro L, Benatti U, De Flora A
Institute of Biological Chemistry, University of Genova, Italy.
Biochem Pharmacol. 1994 Sep 15;48(6):1121-8. doi: 10.1016/0006-2952(94)90148-1.
A new dimeric fluoropyrimidine molecule (5-fluoro-2'-deoxyuridilyl-(5'-->3')-5-fluoro-2'-deoxy-5'-uridylic acid, Compound 1) was chemically synthesized from two separately deblocked 5-fluoro-2'-deoxyuridine mononucleotide moieties. Other structurally related nucleotides, 5-fluoro-2'-deoxyuridine-5'-diphosphate (FdUDP), 5-fluoro-2'-deoxyuridine-5'-triphosphate (FdUTP) and 5-fluoro-2'-deoxyuridine-3',5'-bisphosphate were also synthesized. The structures of all synthesized molecules were verified by mass spectrometric analyses and were consistent with expected molecular mass values. The metabolic patterns of conversion of Compound 1 were investigated both in human erythrocyte lysates and in intact erythrocytes previously loaded with this molecule according to a highly conservative encapsulation procedure. In hemolysates, Compound 1 was transformed to 5-fluoro-2'-deoxyuridine (FUdR) and to 5-fluorouracil (FU) through the intermediate formation of 5-fluoro-2'-deoxyuridine-5'-monophosphate (FdUMP). In intact red cells, Compound 1 still generated FUdR (and to a lesser extent FU), that was then released outside. The conversion pathway involves a phosphodiesterase-catalysed hydrolysis of Compound 1 into two FdUMP molecules, followed by further dephosphorylation to FUdR and by partial conversion to FU. Unlike hemolysates, Compound 1-loaded intact erythrocytes featured transient formation of FdUDP and FdUTP, both metabolites representing storage compounds for the final and sustained production of FUdR and FU. Therefore, human erythrocytes can behave as bioreactors ensuring the time-controlled production and delivery of the two powerful antitumor drugs FUdR and FU from encapsulated Compound 1. This new molecule and other compounds as well (e.g. FdUDP and FdUTP) can be viewed as useful pre-prodrugs, exploitable for intraerythrocytic bioconversion reactions.
一种新的二聚体氟嘧啶分子（5-氟-2'-脱氧尿苷酰基-(5'→3')-5-氟-2'-脱氧-5'-尿苷酸，化合物1）由两个分别脱保护的5-氟-2'-脱氧尿苷单核苷酸部分化学合成。还合成了其他结构相关的核苷酸，5-氟-2'-脱氧尿苷-5'-二磷酸（FdUDP）、5-氟-2'-脱氧尿苷-5'-三磷酸（FdUTP）和5-氟-2'-脱氧尿苷-3',5'-二磷酸。所有合成分子的结构通过质谱分析进行了验证，与预期分子量值一致。根据一种高度保守的包封程序，研究了化合物1在人红细胞裂解物和预先加载该分子的完整红细胞中的代谢转化模式。在溶血产物中，化合物1通过5-氟-2'-脱氧尿苷-5'-单磷酸（FdUMP）的中间形成转化为5-氟-2'-脱氧尿苷（FUdR）和5-氟尿嘧啶（FU）。在完整红细胞中，化合物1仍产生FUdR（以及程度较轻的FU），然后释放到细胞外。转化途径包括磷酸二酯酶催化化合物1水解为两个FdUMP分子，随后进一步脱磷酸化为FUdR，并部分转化为FU。与溶血产物不同，加载化合物1的完整红细胞具有FdUDP和FdUTP的短暂形成，这两种代谢物代表用于最终持续产生FUdR和FU的储存化合物。因此，人红细胞可作为生物反应器，确保从包封的化合物1中按时间控制生产和递送两种强大的抗肿瘤药物FUdR和FU。这种新分子以及其他化合物（如FdUDP和FdUTP）可被视为有用的前药，可用于红细胞内生物转化反应。
