Cancer Chemotherapy and Pharmacology

, Volume 43, Issue 1, pp 80–85 | Cite as

Modulation of cyclophosphamide activity by O 6-alkylguanine-DNA alkyltransferase

  • Henry S. Friedman
  • Anthony E. Pegg
  • Stewart P. Johnson
  • Natalia A. Loktionova
  • M. Eileen Dolan
  • Paul Modrich
  • Robert C. Moschel
  • Robert Struck
  • Thomas P. Brent
  • Susan Ludeman
  • Nancy Bullock
  • Cynthia Kilborn
  • Steve Keir
  • Qing Dong
  • Darell D. Bigner
  • O. Michael Colvin
ORIGINAL ARTICLE

Abstract

Purpose: The human medulloblastoma cell line D283 Med (4-HCR), a line resistant to 4-hydroperoxycyclophosphamide (4-HC), displays enhanced␣repair of DNA interstrand crosslinks induced by phosphoramide mustard. D283 Med (4-HCR) cells are cross-resistant to 1,3-bis(2-chloroethyl)-1-nitrosourea, but partial sensitivity is restored after elevated levels of O6-alkylguanine-DNA alkyltransferase (AGT) are depleted by O6-benzylguanine (O6-BG). Studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) after AGT is depleted by O6-BG. Methods: Limiting dilution and xenograft studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide with or without O6-BG. Results: The activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) was increased after AGT depletion by O6-BG preincubation. Similar studies with Chinese hamster ovary cells, with or without stable transfection with a plasmid expressing the human AGT protein, revealed that the AGT-expressing cells were significantly less sensitive to 4-HC and 4-hydroperoxydidechlorocyclophosphamide. Reaction of DNA with 4-HC, phosphoramide mustard, or acrolein revealed that only 4-HC and acrolein caused a decrease in AGT levels. Conclusions: We propose that a small but potentially significant part of the cellular toxicity of cyclophosphamide in these cells is due to acrolein, and that this toxicity is abrogated by removal of the acrolein adduct from DNA by AGT.

Key words Alkylating agents Antineoplastic agents Cyclophosphamide Drug resistance Nitrogen mustard compounds 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Henry S. Friedman
    • 1
  • Anthony E. Pegg
    • 5
  • Stewart P. Johnson
    • 1
  • Natalia A. Loktionova
    • 5
  • M. Eileen Dolan
    • 6
  • Paul Modrich
    • 4
  • Robert C. Moschel
    • 9
  • Robert Struck
    • 7
  • Thomas P. Brent
    • 8
  • Susan Ludeman
    • 3
  • Nancy Bullock
    • 1
  • Cynthia Kilborn
    • 1
  • Steve Keir
    • 1
  • Qing Dong
    • 1
  • Darell D. Bigner
    • 2
  • O. Michael Colvin
    • 3
  1. 1.Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA Tel: +1-919-684-5301; Fax: +1-919-684-6674US
  2. 2.Department of Pathology, Duke University Medical Center, Durham, NC 27710, USAUS
  3. 3.Department of Medicine, Duke University Medical Center, Durham, NC 27710, USAUS
  4. 4.Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USAUS
  5. 5.Department of Cellular and Molecular Physiology, The Milton S. Hershey Medical Center, Hershey, PA 17033, USAUS
  6. 6.Department of Medicine, University of Chicago, Chicago, IL 60637, USAUS
  7. 7.Southern Research Institute, Birmingham, AL 35255, USAUS
  8. 8.Department of Molecular Pharmacology, St. Jude Children's Research Center, Memphis, TN 38101, USAUS
  9. 9.NCI-Frederick Cancer Research and Development Center, Frederick, MD 21702, USAUS

Personalised recommendations