This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Pizzorno, G. Articles by Beardsley, G. P. Search for Related Content PubMed PubMed Citation Articles by Pizzorno, G. Articles by Beardsley, G. P.

(6R)-5,10-Dideaza-5,6,7,8-tetrahydrofolic Acid Effects on Nucleotide Metabolism in CCRF-CEM Human T-Lymphoblast Leukemia Cells¹

Departments of Pediatrics, Pharmacology, and Medicine, Yale University School of Medicine, New Haven, Connecticut 06510

(6R)-5,10-Dideaza-5,6,7,8-tetrahydrofolic acid [(6R)DDATHF] is a folate antimetabolite with activity specifically directed against de novo purine synthesis, primarily through inhibition of glycinamide ribonucleotide transformylase. This inhibition resulted in major changes in the size of the nucleotide pools in CCRF-CEM cells. After a 4-h incubation with 1 µM (6R)DDATHF, dramatic reductions in the ATP and GTP pools were observed, with almost no effect on CTP, UTP, and deoxyribonucleotide pools. When the incubation was continued in drug-free medium, recovery of ATP and GTP pools was protracted. ATP did not return to normal until 24–36 h, and GTP pools were only partially repleted by 48 h. The ATP and GTP pools were not affected when the initial 4-h incubation with (6R)DDATHF was conducted in the presence of 100 µM hypoxanthine. Addition of hypoxanthine to the medium after a 4-h incubation with (6R)DDATHF caused rapid recovery of the ATP and GTP pools. Similar effects were seen when the purine precursor aminoimidazole carboxamide was used in place of hypoxanthine. The effect of (6R)DDATHF on nucleotide pools and the capability of hypoxanthine or aminoimidazole carboxamide to prevent or reverse this phenomenon correlated directly with the inhibition of cell growth. Presumably as a consequence of the decrease in purine nucleotide triphosphate levels, the conversion of exogenously added uridine, thymidine, and deoxyuridine to nucleotides was markedly decreased. These effects were protracted for almost 48 h and were also reversed by hypoxanthine. Differential repletion of ATP and GTP pools after (6R)DDATHF pretreatment demonstrated that diminished precursor phosphorylation is primarily a consequence of GTP rather than ATP starvation.

¹ Supported by NIH Research Grants CA 42367 and CA 57320.

² Special Fellow of the Leukemia Society of America.

³ Recipient of an American Cancer Society Faculty Research Award. To whom requests for reprints should be addressed, at Department of Pediatrics, Yale University School of Medicine, 333 Cedar St., P. O. Box 3333, New Haven, CT 06510-8064.

Received 2/26/90. Accepted 2/22/91.

This article has been cited by other articles:

				J. L. Bronder and R. G. Moran A Defect in the p53 Response Pathway Induced by de Novo Purine Synthesis Inhibition J. Biol. Chem., December 5, 2003; 278(49): 48861 - 48871. [Abstract] [Full Text] [PDF]

				N. V. Oleinik and S. A. Krupenko Ectopic Expression of 10-Formyltetrahydrofolate Dehydrogenase in A549 Cells Induces G1 Cell Cycle Arrest and Apoptosis Mol. Cancer Res., June 1, 2003; 1(8): 577 - 588. [Abstract] [Full Text] [PDF]

				J. L. Bronder and R. G. Moran Antifolates Targeting Purine Synthesis Allow Entry of Tumor Cells into S Phase Regardless of p53 Function Cancer Res., September 15, 2002; 62(18): 5236 - 5241. [Abstract] [Full Text] [PDF]

				S. A. Krupenko and N. V. Oleinik 10-Formyltetrahydrofolate Dehydrogenase, One of the Major Folate Enzymes, Is Down-Regulated in Tumor Tissues and Possesses Suppressor Effects on Cancer Cells Cell Growth Differ., May 1, 2002; 13(5): 227 - 236. [Abstract] [Full Text] [PDF]