Selective cytotoxicity of 3-amino-L-tyrosine correlates with peroxidase activity

John G. Bruno, Terence S. Herman, V. Lorenzo Cano, Lucy Stribling, Johnathan L. Kiel

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

In the presence of 3-amino-L-tyrosine (3-AT), abundant brown pigment forms in human HL-60 cells, but not in a variety of other cell lines, which are reported to be lower in mean myeloperoxidase (MPO) content than HL-60. Cells were assessed for peroxidase activity with an ABTS-based colorimetric assay and compared to values obtained with known amounts of human myeloperoxidase. HL-60 cells were estimated to contain the equivalent of 37.1 ng myeloperoxidase/106 cells versus 26.1 and 5.0 ng/106 cells for human K562 and murine RAW 264.7 cell lines, respectively. HL-60 cells exhibited a nearly 60% inhibition of proliferation and > 70% reduction in cell viability after 4 d of culture in the presence of 100 μg 3-AT per ml. Higher concentrations of 3-AT (up to 400 μg/ml) for 4 d reduced HL-60 proliferation by 80% and decreased viability to 1-3%. Comparable levels of cytotoxicity were achieved in KG-1 cells after 7 d with 200 or 400 μg 3-AT per ml. K562 cells exhibited a 40% reduction in cell number after 7 d with 400 μg 3-AT per ml, but concentrations less than 400 μg/ml did not significantly affect K562 proliferation. K562 viability remained unchanged with doses of 3-AT up to 400 μg/ml. RAW 264.7 cells exhibited unchanged viability and proliferation in the presence of 3-AT at concentrations up to 400 μg 3-AT per ml. K562, KG-1, and RAW 264.7 cells exhibited no evidence of brown pigment formation in the presence of 3-AT and medium containing 10% fetal bovine serum. However, RAW 264.7 cells that were converted to protein-free medium and exposed to 3-AT exhibited intense brown pigment in some cell nuclei. A high percentage of HL-60 cells treated with 3-AT exhibited membrane blebbing, pyknosis, and nuclear fragmentation, which was not observed among other 3-AT-treated cell lines. A mechanism involving toxic intermediates of peroxidase-mediated 'aminomelanin' formation is hypothesized.

Original languageEnglish (US)
Pages (from-to)376-382
Number of pages7
JournalIn Vitro Cellular and Developmental Biology - Animal
Volume35
Issue number7
DOIs
StatePublished - 1999

Keywords

  • Apoptosis
  • HL-60
  • Leukemia
  • Melanin
  • Myeloperoxidase
  • Pyknosis

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology

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