Dihydropyrimidine dehydrogenase activity in human peripheral blood mononuclear cells and liver : population characteristics, newly identified deficient patients, and clinical implication in 5-fluorouracil chemotherapy

• Published in: Cancer research (Chicago, Ill.) Vol. 53; no. 22; pp. 5433 - 5438
• Main Authors: LU, Z, ZHANG, R, DIASIO, R. B
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 15-11-1993
• Subjects: Adult; Aged; Antineoplastic agents; Biological and medical sciences; Breast Neoplasms - enzymology; Colonic Neoplasms - enzymology; Dihydrouracil Dehydrogenase (NADP); Female; Fluorouracil - adverse effects; Fluorouracil - therapeutic use; General aspects; Humans; Liver - enzymology; Male; Medical sciences; Middle Aged; Oxidoreductases - analysis; Oxidoreductases - blood; Oxidoreductases - deficiency; Pharmacology. Drug treatments; Rectal Neoplasms - enzymology; Reference Values; Sensitivity and Specificity; Antineoplastic agent; Human; Pharmacogenetics; Enzyme; Liver; ); Dihydropyrimidine dehydrogenase (NADP; Malignant tumor; Metabolism; Chemotherapy; Mononuclear cell; Treatment; Enzymatic activity; Interindividual comparison; Genetics; Pyrimidine derivatives; Oxidoreductases; Fluorine Organic compounds; Pharmacokinetics
• ISSN: 0008-5472; 1538-7445

Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-fluorouracil (FUra), one of the most widely used anticancer drugs. Previous studies from our laboratory demonstrated the clinical importance of DPD in cancer patients (G. D. Heggie, J-P. Sommadossi, D. S. Cross, W. J. Huster, and R. B. Diasio. Cancer Res., 47: 2203-2206, 1987; B. E. Harris, R. Song, S-j. Soong, and R. B. Diasio. Cancer Res., 50: 197-201, 1990), particularly in those with DPD deficiency who experience severe FUra toxicity (including death) following FUra treatment [R. B. Diasio, T. L. Beavers, and J. T. Carpenter. J. Clin. Invest., 81: 47-51, 1988; B. E. Harris, J. T. Carpenter, and R. B. Diasio. Cancer (Phila.), 68: 499-501, 1991]. We now suggest that measurement of DPD activity may be useful in routine screening of cancer patients prior to FUra treatment. In this paper, we describe the following serial studies: (a) we developed a sensitive, accurate, and precise DPD assay and a storage method to stabilize DPD activity, permitting large scale DPD screening in cancer patients; (b) we demonstrated a normal distribution (Gaussian distribution) of human DPD activity from peripheral blood mononuclear cells (PBM-DPD) in a population study. Baselines for PBM-DPD with fresh and frozen samples were 0.425 +/- 0.124 (SD) and 0.189 +/- 0.064 nmol/min/mg protein, respectively. The 95% and 99% distribution ranges for both fresh and frozen samples were also determined, providing criteria for detection of DPD-deficient patients; (c) we identified nine new patients with profound or partial DPD deficiency; (d) we determined a baseline for human liver DPD activity, which was shown to be 0.360 +/- 0.182 nmol/min/mg protein (frozen samples); (e) we did a preliminary evaluation of liver DPD from deficient patients. Low liver DPD activity in two deficient patients correlated with low PBM-DPD activity. Using a polyclonal antibody raised against human liver DPD in our laboratory (Z. Lu, R. Zhang, and R. B. Diasio. J. Biol. Chem., 267: 17102-17109, 1992), Western blot analysis demonstrated decreased DPD protein in the liver cytosol from DPD-deficient patients compared to normal subjects. These results may be useful in improving the effectiveness and/or lessening the toxicity of FUra chemotherapy.