Inhibition of pyrimidine de novo synthesis by DUP-785 (NSC 368390)

G. J. Peters, S. L. Sharma, E. Laurensse, H. M. Pinedo

Research output: Contribution to journalArticle

Abstract

The mechanism of action of NSC 368390 (DUP-785, 6-fluoro-2-(2′-fluoro-1, 1′-biphenyl-4-yl)-3-methyl-4-quinoline carboxylic acid sodium salt) was studied using three different approaches. First, we studied growth inhibition by DUP-785 in L1210 leukemia cells and M5 melanoma cells. The concentrations causing 50% growth inhibition after 48 hr of culture were 5.8 and 0.6 μM, respectively. DUP-785 had to be present continuously throughout culture. Growth inhibition by 25 μM DUP-785 could be prevented by addition of 1 mM uridine or orotic acid to cultures of these cell lines; in M5 cells cytidine was also able to prevent growth inhibition. Dihydro-orotic acid (DHO) and carbamyl-aspartate were not able to prevent growth inhibition by DUP-785. Second, we studied accumulation of orotic acid and of orotidine induced by incubation with 1 μM pyrazofurin, an inhibitor of the orotate phosphoribosyl-transferase-orotidine-monophosphate decarboxylase complex. Addition of DUP-785 to the culture medium prevented the orotic acid accumulation. Furthermore, DUP-785 prevented accumulation of H14CO3 - into orotic acid of pyrazofurin-treated L1210 cells. Third, we measured the effect of DUP-785 on DHO-dehydrogenase (DHO-DH), since the results indicated that this enzyme was affected by DUP-785. DHO-DH was assayed in isolated rat liver mitochondria. The Km for L-DHO was about 12 μM. DUP-785 appeared to be a potent inhibitor of DHO-DH with an apparent Ki of about 0.1 μM and an apparent Ki′ of about 0.8 μM. The mode of inhibition appeared to be linear mixed type. After exposure of L1210 cells to 25 μM DUP-785 for 2 hr DHO-DH was almost completely inhibited. After suspension in fresh medium without drug, DHO-DH activity was recovered to about 60% after 24 hr. In conclusion, DUP-785 is a potent inhibitor of pyrimidine de novo biosynthesis, by inhibition of the mitochondrial enzyme DHO-DH.

Original languageEnglish (US)
Pages (from-to)235-244
Number of pages10
JournalInvestigational New Drugs
Volume5
Issue number3
DOIs
StatePublished - Sep 1987
Externally publishedYes

Keywords

  • dihydroorotic acid dehydrogenase
  • NSC 368390 (DUP-785)
  • pyrazofurin
  • pyrimidine de novo

ASJC Scopus subject areas

  • Pharmacology
  • Molecular Medicine

Fingerprint Dive into the research topics of 'Inhibition of pyrimidine de novo synthesis by DUP-785 (NSC 368390)'. Together they form a unique fingerprint.

  • Cite this

    Peters, G. J., Sharma, S. L., Laurensse, E., & Pinedo, H. M. (1987). Inhibition of pyrimidine de novo synthesis by DUP-785 (NSC 368390). Investigational New Drugs, 5(3), 235-244. https://doi.org/10.1007/BF00175293