Inhibition of poly(adenosine diphosphate-ribose) polymerase by thymidine and thymidine analogues in L1210 cells and its relationship to the potentiation of the antitumor activity of 1,3-bis(2-chloroethyl)-1-nitrosourea but not of 3'-[3-(2-chloroethyl)-3-nitrosoureido]-3'-deoxythymidine. 1991

E M August, and D L Cooper, and W H Prusoff
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06510.

The coadministration of thymidine (dThd) with either 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) or 3'-[3-(2-chloroethyl)-3-nitrosoureido]-3'-deoxythymidine (3'-CTNU) to L1210-bearing mice significantly enhanced the antitumor activity of both nitrosoureas (T-S. Lin and W. H. Prusoff, Cancer Res., 47:394-397, 1987, and T-S. Lin, P.H. Fischer, J. C. Marsh, and W. H. Prusoff, Cancer Res., 42:1624-1629, 1982). As a possible mechanism for this observed enhancement, we have investigated the role of dThd as an inhibitor of poly(ADP-ribose) polymerase (ADPRP), an enzyme which is activated in response to DNA damage. Exposure of L1210 cells in culture to 50 microM BCNU resulted in a greater than 10-fold increase in ADPRP activity within 3-4 h. The polymerase activity increased with increasing BCNU concentration after a 4-h exposure, reaching apparent saturation at 50 microM BCNU. However, this activation was abolished by 2 mM dThd. Median inhibition of the ADPRP activity elicited by 30 and 75 microM BCNU occurred at 38 and 135 microM dThd, respectively. When BCNU was replaced by 3'-CTNU, no activation of ADPRP was observed, even at or above concentration of 3'-CTNU previously shown to cause DNA damage. 3'-Amino-3'-deoxythymidine, the principal hydrolysis product of 3'-CTNU, was found to be an inhibitor of BCNU-stimulated ADPRP activity with potency similar to dThd. Furthermore, intact 3'-CTNU was found to inhibit BCNU-stimulated ADPRP activity. Although 3'-CTNU should be capable of activating ADPRP by causing DNA damage, our results suggest that no net activation is observed due to inhibition by the various thymidine species present. Thus, inhibition of ADPRP by dThd following DNA damage by BCNU is consistent with the potentiation of antitumor activity previously reported. However, the observed potentiation of 3'-CTNU activity by dThd does not appear to result from such a mechanism.

UI MeSH Term Description Entries
D007939 Leukemia L1210 An experimental LYMPHOCYTIC LEUKEMIA of mice. Leukemia L 1210,L 1210, Leukemia,L1210, Leukemia
D002330 Carmustine A cell-cycle phase nonspecific alkylating antineoplastic agent. It is used in the treatment of brain tumors and various other malignant neoplasms. (From Martindale, The Extra Pharmacopoeia, 30th ed, p462) This substance may reasonably be anticipated to be a carcinogen according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985). (From Merck Index, 11th ed) BCNU,1,3-Bis(2-Chloroethyl)-1-Nitrosourea,BiCNU,FIVB,N,N'-Bis(2-Chloroethyl)-N-Nitrosourea,Nitrumon
D004247 DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA, Double-Stranded,Deoxyribonucleic Acid,ds-DNA,DNA, Double Stranded,Double-Stranded DNA,ds DNA
D004249 DNA Damage Injuries to DNA that introduce deviations from its normal, intact structure and which may, if left unrepaired, result in a MUTATION or a block of DNA REPLICATION. These deviations may be caused by physical or chemical agents and occur by natural or unnatural, introduced circumstances. They include the introduction of illegitimate bases during replication or by deamination or other modification of bases; the loss of a base from the DNA backbone leaving an abasic site; single-strand breaks; double strand breaks; and intrastrand (PYRIMIDINE DIMERS) or interstrand crosslinking. Damage can often be repaired (DNA REPAIR). If the damage is extensive, it can induce APOPTOSIS. DNA Injury,DNA Lesion,DNA Lesions,Genotoxic Stress,Stress, Genotoxic,Injury, DNA,DNA Injuries
D004357 Drug Synergism The action of a drug in promoting or enhancing the effectiveness of another drug. Drug Potentiation,Drug Augmentation,Augmentation, Drug,Augmentations, Drug,Drug Augmentations,Drug Potentiations,Drug Synergisms,Potentiation, Drug,Potentiations, Drug,Synergism, Drug,Synergisms, Drug
D004789 Enzyme Activation Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. Activation, Enzyme,Activations, Enzyme,Enzyme Activations
D000067856 Poly(ADP-ribose) Polymerase Inhibitors Chemicals and drugs that inhibit the action of POLY(ADP-RIBOSE)POLYMERASES. Inhibitors of Poly(ADP-ribose) Polymerase,PARP Inhibitor,Poly(ADP-Ribose) Polymerase Inhibitor,Poly(ADP-ribosylation) Inhibitor,Inhibitors of Poly(ADP-ribose) Polymerases,PARP Inhibitors,Poly(ADP-ribosylation) Inhibitors,Inhibitor, PARP,Inhibitors, PARP
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D000970 Antineoplastic Agents Substances that inhibit or prevent the proliferation of NEOPLASMS. Anticancer Agent,Antineoplastic,Antineoplastic Agent,Antineoplastic Drug,Antitumor Agent,Antitumor Drug,Cancer Chemotherapy Agent,Cancer Chemotherapy Drug,Anticancer Agents,Antineoplastic Drugs,Antineoplastics,Antitumor Agents,Antitumor Drugs,Cancer Chemotherapy Agents,Cancer Chemotherapy Drugs,Chemotherapeutic Anticancer Agents,Chemotherapeutic Anticancer Drug,Agent, Anticancer,Agent, Antineoplastic,Agent, Antitumor,Agent, Cancer Chemotherapy,Agents, Anticancer,Agents, Antineoplastic,Agents, Antitumor,Agents, Cancer Chemotherapy,Agents, Chemotherapeutic Anticancer,Chemotherapy Agent, Cancer,Chemotherapy Agents, Cancer,Chemotherapy Drug, Cancer,Chemotherapy Drugs, Cancer,Drug, Antineoplastic,Drug, Antitumor,Drug, Cancer Chemotherapy,Drug, Chemotherapeutic Anticancer,Drugs, Antineoplastic,Drugs, Antitumor,Drugs, Cancer Chemotherapy
D013936 Thymidine A nucleoside in which THYMINE is linked to DEOXYRIBOSE. 2'-Deoxythymidine,Deoxythymidine,2' Deoxythymidine

Related Publications

E M August, and D L Cooper, and W H Prusoff
August 1995, Gastroenterology,
E M August, and D L Cooper, and W H Prusoff
January 1992, Cancer immunology, immunotherapy : CII,
E M August, and D L Cooper, and W H Prusoff
October 1979, Journal of medicinal chemistry,
Copied contents to your clipboard!