O6-benzylguanine-mediated enhancement of nitrosourea activity in Mer- central nervous system tumor xenografts - Implications for clinical trials

Stephen T. Keir, M. Eileen Dolan, Anthony Pegg, Amy Lawless, Robert C. Moschel, Darell D. Bigner, Henry S. Friedman

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Purpose: To evaluate the role of 1,3-bis(2-chloroethyl)-l-nitrosourea (BCNU) plus O6-benzylguanine (O6-BG) in the treatment of both Mer+ and Mer- tumors. Methods: The effect of pretreatment with O6-BG on the activity of BCNU against Mer- human central nervous tumor xenografts D-54 MG and D- 245 MG was evaluated in athymic nude mice. Results: BCNU (1.0 LD10; dose lethal to 10% of treated animals) produced growth delays of 8.9 days and 7.5 days and tumor regressions in six of ten and one of nine animals against D-54 MG, which was derived from a human malignant glioma xenograft. Dose reduction of BCNU to 0.38 LD10 eliminated antitumor activity. The combination of BCNU (0.38 LD10) plus O6-BG produced growth delays of 8.8 days and 7.9 days, with tumor regressions in four of ten and two of nine animals, respectively. BCNU (1.0 LD10) produced a growth delay of 49.8 days and ten of ten tumor regressions against D-245 MG, which was derived from a glioblastoma multiforme. BCNU (0.38 LD10) produced a growth delay of 19.4 days, with nine of ten tumor regressions. The combination of BCNU (0.38 LD10) plus O6-BG produced a growth delay of 65.7 days and seven of eight tumor regressions. Conclusion: These results suggest that the combination of BCNU plus O6-BG may be a rational intervention for both Mer+ as well as Mer- tumors.

Original languageEnglish (US)
Pages (from-to)437-440
Number of pages4
JournalCancer Chemotherapy and Pharmacology
Issue number6
Publication statusPublished - Jan 1 2000


All Science Journal Classification (ASJC) codes

  • Oncology
  • Toxicology
  • Pharmacology
  • Cancer Research
  • Pharmacology (medical)

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