Abstract
5′-O-Trityl derivatives of thymidine (dThd), (E)-5-(2-bromovinyl)-2′-deoxyuridine (BVDU), and their acyclic analogs 1-[(Z)-4-triphenylmethoxy-2-butenyl]thymine (KIN-12) and (E)-5-(2-bromovinyl)-1-[(Z)-4-triphenylmethoxy-2-butenyl]uracil (KIN-52) have been synthesized and evaluated for their inhibitory activity against the amino acid sequence related mitochondrial dThd kinase (TK-2), herpes simplex virus type 1 (HSV-1) TK, andDrosophila melanogaster multifunctional 2′-deoxynucleoside kinase (Dm-dNK). Several compounds proved markedly inhibitory to these enzymes and represent a new generation of nucleoside kinase inhibitors. KIN-52 was the most potent and selective inhibitor of TK-2 (IC50, 1.3 μM;Ki, 0.50 μM;Ki/Km, 0.37) but was not inhibitory against HSV-1 TK and Dm-dNK at 100 μM. As found for the alternative substrate BVDU, the tritylated compounds competitively inhibited the three enzymes with respect to dThd. However, whereas BVDU behaved as a noncompetitive inhibitor (alternative substrate) of TK-2 and HSV-1 TK with respect to ATP as the varying substrate, the novel tritylated enzyme inhibitors emerged as reversible purely uncompetitive inhibitors of these enzymes. Computer-assisted modeling studies are in agreement with these findings. The tritylated compounds do not act as alternative substrates and they showed a type of kinetics against the nucleoside kinases different from that of BVDU. KIN-12, and particularly KIN-52, are the very first non-nucleoside specific inhibitors of TK-2 reported and may be useful for studying the physiological role of the mitochondrial TK-2 enzyme.
Footnotes
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This work was supported by a grant from the “Geconcerteerde Onderzoeksacties–Vlaanderen” (GOA) (krediet number 00/12), the “Belgische Federatie tegen Kanker”, the Spanish Comisión Interministerial de Ciencia y Tecnologica [SAF2000-0153-(02-01)], and the European Commission (QLG1-CT-2001-01004).
- Abbreviations:
- dThd
- 2′-deoxythymidine
- TK
- thymidine kinase
- dUrd
- 2′-deoxyuridine
- dCyd
- 2′-deoxycytidine
- dGuo
- 2′-deoxyguanosine
- dAdo
- 2′-deoxyadenosine kinase
- dGK
- 2′-deoxyguanosine kinase
- dNK
- 2′-deoxynucleoside kinase
- Dm
- Drosophila melanogaster
- BVDU
- (E)-5′-(2-bromovinyl)-2′-deoxyuridine
- HSV
- herpes simplex virus
- BVU
- (E)-5-(2-bromovinyl)uracil
- GST
- glutathione S-transferase
- CHAPS
- 3-[(3-cholamidopropyl)dimethylammonio]propanesulfonate
- THF
- tetrahydrofuran
- KIN5
- (E)-5-(2-bromovinyl)-1-(2′-deoxy-5′-O-triphenylmethyl)uridine
- KIN6
- 5′-O-triphenylmethyl-thymidine
- KIN12
- 1-[(Z)-4-(triphenylmethoxy)-2-butenyl]thymine
- KIN39
- (R,S)-1-[3-hydroxy-4-(triphenylmethoxy)butyl]thymine
- KIN-52
- (E)-5-(2-bromovinyl)-1-[(Z)-4-(triphenylmethoxy)-2-butenyl]uracil
- Received July 29, 2002.
- Accepted October 28, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
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