caa a22 4500 477125921 CHVBK 20180405111649.0 cr unu---uuuuu 170330e19970601xx s 000 0 eng 10.1023/A:1012133902314 doi (NATIONALLICENCE)springer-10.1023/A:1012133902314 Cellular Delivery of Nucleoside Diphosphates: A Prodrug Approach [Elektronische Daten] [Shin Kang, Achintya Sinhababu, Joseph Cory, Beverly Mitchell, Dhiren Thakker, Moo Cho] Purpose. This study is concerned with cellular delivery/generation of 2′-azido-2′-deoxyuridine and -deoxycytidine diphosphate (N3UDP or N3CDP), potent inhibitors of ribonucleotide reductase. It characterizes the phosphorylation steps involved in the conversion of 2′-azido-2′-deoxyuridine (N3Urd) and 2′-azido-2′-deoxycytidine (N3Cyd) to the corresponding diphosphates and explores a prodrug approach in cellular delivery of the inhibitor which circumvents the requirement of deoxynucleoside kinases. Methods. Cell growth of CHO and 3T6 cells of known deoxycytidine kinase level was determined in the presence of N3Urd and N3Cyd. Activity of ribonucleotide reductase was determined in the presence of the azidonucleosides as well as their mono- or di-phosphates in a Tween 80-containing permeabilizing buffer. A prodrug of 5′-monophosphate of N3Urd was prepared and its biological activity was evaluated with CHO cells as well as with cells transfected with deoxycytidine kinase. Results. N3Urd failed to inhibit the growth of both cell lines, while N3Cyd was active against 3T6 cells and moderately active against CHO cells. These results correlate with the deoxycytidine kinase levels found in the cells. Importance of the kinase was further established with the finding that the nucleoside analogs were inactive as reductase inhibitors in a permeabilized cell assay system while their mono- and di-phosphates were equally active. The prodrug was active in cell growth inhibition regardless of the deoxycytidine kinase level. Conclusions. The azidonucleosides become potent inhibitors of the reductase by two sequential phosphorylation steps. The present study indicates that the first step to monophosphate is rate-limiting, justifying a prodrug approach with the monophosphate. Plenum Publishing Corporation, 1997 2′-azido-2′-deoxycytidine nationallicence 2′-azido-2′-deoxyuridine nationallicence 2′-azido-2′-deoxyuridine 5′-diphosphate nationallicence ribonucleotide reductase nationallicence phosphorylation of nucleoside analogue nationallicence prodrug nationallicence anticancer agent nationallicence Kang Shin Division of Pharmaceutics, University of North Carolina School of Pharmacy, Chapel Hill, North Carolina aut Sinhababu Achintya Department of BioMet, Glaxo Wellcome Research Institute, Research Triangle Park, 27709, North Carolina aut Cory Joseph Department of Biochemistry, East Carolina University School of Medicine, Greenville, North Carolina aut Mitchell Beverly Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina aut Thakker Dhiren Department of BioMet, Glaxo Wellcome Research Institute, Research Triangle Park, 27709, North Carolina aut Cho Moo Division of Pharmaceutics, University of North Carolina School of Pharmacy, Chapel Hill, North Carolina aut Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/6(1997-06-01), 706-712 0724-8741 14:6<706 1997 14 11095 https://doi.org/10.1023/A:1012133902314 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1012133902314 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kang Shin Division of Pharmaceutics, University of North Carolina School of Pharmacy, Chapel Hill, North Carolina aut NATIONALLICENCE 700 1- Sinhababu Achintya Department of BioMet, Glaxo Wellcome Research Institute, Research Triangle Park, 27709, North Carolina aut NATIONALLICENCE 700 1- Cory Joseph Department of Biochemistry, East Carolina University School of Medicine, Greenville, North Carolina aut NATIONALLICENCE 700 1- Mitchell Beverly Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina aut NATIONALLICENCE 700 1- Thakker Dhiren Department of BioMet, Glaxo Wellcome Research Institute, Research Triangle Park, 27709, North Carolina aut NATIONALLICENCE 700 1- Cho Moo Division of Pharmaceutics, University of North Carolina School of Pharmacy, Chapel Hill, North Carolina aut NATIONALLICENCE 773 0- Pharmaceutical Research Kluwer Academic Publishers-Plenum Publishers 14/6(1997-06-01), 706-712 0724-8741 14:6<706 1997 14 11095 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer