High-performance liquid chromatography separation of aminopterin-polyglutamates within red blood cells of children treated for acute lymphoblastic leukemia

Veena Vijayanathan, Angela K. Smith, John A. Zebala, Barton A. Kamen, Peter D. Cole

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Aminopterin (AMT), like the related compound methotrexate (MTX), is a drug with anticancer and antiinflammatory efficacy that works by interfering with synthetic reactions dependent on the vitamin folic acid. Red blood cell (RBC) precursors will accumulate antifolates like AMT and MTX through the same mechanism by which they take up folate. Intracellular folate and antifolates are then metabolized to polyglutamates that remain within the mature RBCs. RBC MTX has been correlated with toxicity and/or treatment efficacy among patients with acute lymphoblastic leukemia (ALL) or rheumatoid arthritis. Because AMT may offer clinically relevant advantages over MTX, we are testing whether it can be administered safely in multiagent therapy to children with ALL. Total RBC AMT was measured to monitor compliance with this oral, outpatient regimen, and to estimate AMT exposure to the bone marrow. Here we describe methods for quantifying each AMT-polyglutamate species within the RBCs of patients. The assay was linear over a concentration range of 62.5-500 nmol/L. Recovery of individual AMT-polyglutamates ranged from 85% to 92%, and the intraday coefficients of variation were 1.3% to 3.6%. Long-chain AMT-polyglutamates (triglutamate and tetraglutamate forms) accounted for over 40% of intracellular AMT within the RBCs of patients. Patients with long-chain AMT polyglutamate concentrations above the median tended to have lower mean neutrophil counts during weekly AMT therapy, which suggests that RBC AMT polyglutamate accumulation may correlate with hematologic toxicity. As AMT continues to be tested in clinical trials, the methods described here will be useful to define relationships between clinical response to AMT and RBC accumulation of AMT-polyglutamates.

Original languageEnglish (US)
Pages (from-to)367-373
Number of pages7
JournalTranslational Research
Volume150
Issue number6
DOIs
StatePublished - Dec 2007
Externally publishedYes

Fingerprint

Aminopterin
Polyglutamic Acid
High performance liquid chromatography
Precursor Cell Lymphoblastic Leukemia-Lymphoma
Blood
Erythrocytes
High Pressure Liquid Chromatography
Cells
Methotrexate
Folic Acid
Folic Acid Antagonists
Toxicity

ASJC Scopus subject areas

  • Medicine(all)
  • Biochemistry, medical
  • Public Health, Environmental and Occupational Health

Cite this

High-performance liquid chromatography separation of aminopterin-polyglutamates within red blood cells of children treated for acute lymphoblastic leukemia. / Vijayanathan, Veena; Smith, Angela K.; Zebala, John A.; Kamen, Barton A.; Cole, Peter D.

In: Translational Research, Vol. 150, No. 6, 12.2007, p. 367-373.

Research output: Contribution to journalArticle

Vijayanathan, Veena ; Smith, Angela K. ; Zebala, John A. ; Kamen, Barton A. ; Cole, Peter D. / High-performance liquid chromatography separation of aminopterin-polyglutamates within red blood cells of children treated for acute lymphoblastic leukemia. In: Translational Research. 2007 ; Vol. 150, No. 6. pp. 367-373.
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