Effect of AZT on thymidine phosphorylation in cultured H9c2, U-937, and Raji cell lines

Matthew D. Lynx, Bae Kwang Kang, Edward E. McKee

Research output: Contribution to journalArticle

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Abstract

3′-Azido-3′-deoxythymidine (AZT) has been shown to be a potent inhibitor of thymidine kinase 2 in work from this laboratory. Inhibition results in decreased salvage of thymidine to TTP, which may lead to depletion of the TTP pool and result in the mitochondrial dysfunction and mt-DNA depletion observed with AZT toxicity. The effect of AZT on thymidine phosphorylation in growing cells expressing thymidine kinase 1 has not been shown. Three cell lines were used in these experiments: H9c2, derived from rat cardiomyoblasts; U-937, derived from human monocytes; and Raji, derived from human lymphoblasts. AZT inhibited growth in a concentration-dependent manner in U-937 cells, but not the other cell lines. The phosphorylation of [3H]-thymidine or [3H]-AZT was determined during log growth. All cell lines salvaged and phosphorylated thymidine to TTP, with TTP the major product. The U-937 cells had a much more active salvage pathway than the other cells. All cell lines phosphorylated AZT to the triphosphate, but the major product was AZTMP. The AZT inhibition of growth of the U-937 cells did not correlate with levels of the phosphorylated AZT. In contrast, pro-drug AZT was shown to inhibit thymidine phosphorylation in all lines with 50% inhibition concentrations (IC50) ranging from 4.4 to 21.9 μM. Since the U-937 cells expressed higher activity of the salvage pathway than the other cell lines, the U-937 cells may rely more heavily on the salvage pathway for TTP synthesis, accounting for AZT inhibition of growth.

Original languageEnglish
Pages (from-to)1610-1615
Number of pages6
JournalBiochemical Pharmacology
Volume75
Issue number8
DOIs
StatePublished - Apr 15 2008

Fingerprint

Phosphorylation
Thymidine
Salvaging
Cells
Cell Line
Growth
Zidovudine
Prodrugs
Toxicity
Rats
Inhibitory Concentration 50
Monocytes
thymidine 5'-triphosphate
DNA
Experiments

Keywords

  • AZT
  • Cultured cells
  • Mitochondrial toxicity
  • Reverse transcriptase inhibitors
  • Thymidine

ASJC Scopus subject areas

  • Pharmacology

Cite this

Effect of AZT on thymidine phosphorylation in cultured H9c2, U-937, and Raji cell lines. / Lynx, Matthew D.; Kang, Bae Kwang; McKee, Edward E.

In: Biochemical Pharmacology, Vol. 75, No. 8, 15.04.2008, p. 1610-1615.

Research output: Contribution to journalArticle

Lynx, Matthew D. ; Kang, Bae Kwang ; McKee, Edward E. / Effect of AZT on thymidine phosphorylation in cultured H9c2, U-937, and Raji cell lines. In: Biochemical Pharmacology. 2008 ; Vol. 75, No. 8. pp. 1610-1615.
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