Reduced tamoxifen accumulation is not associated with stimulated growth in tamoxifen resistance

Juhani Maenpaa, Valerie Wiebe, Gregory Wurz, Steven Koester, Vernon Emshoff, Robert Seymour, Michael DeGregorio

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

To study tamoxifen resistance-stimulated growth, 30 female ovariectomized nude mice were implanted with tamoxifen-resistant tumors and treated with 10-1000 μg/day of tamoxifen citrate subcutaneously. Tamoxifen stimulated MCF-7 tumor growth in a dose-dependent manner, with tumoral tamoxifen concentrations increasing proportionally to the dose (1-13 nmol/g), as measured by high-performance liquid chromatography (HPLC). Flow-cytometric analysis revealed that tamoxifen-resistant tumors had a different DNA content as compared with wild-type MCF-7 cells. In contrast to earlier results, these data suggest that tamoxifen resistance-stimulated growth is associated with increasing rather than decreasing tumoral tamoxifen concentrations. Furthermore, the observed ploidy changes in the tamoxifen-resistant tumors imply that a genetic basis may exist for the development of tamoxifen resistance.

Original languageEnglish (US)
Pages (from-to)149-152
Number of pages4
JournalCancer Chemotherapy and Pharmacology
Volume35
Issue number2
DOIs
StatePublished - Mar 1994

Keywords

  • Breast Cancer
  • Resistance
  • Tamoxifen

ASJC Scopus subject areas

  • Pharmacology
  • Oncology
  • Cancer Research

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  • Cite this

    Maenpaa, J., Wiebe, V., Wurz, G., Koester, S., Emshoff, V., Seymour, R., & DeGregorio, M. (1994). Reduced tamoxifen accumulation is not associated with stimulated growth in tamoxifen resistance. Cancer Chemotherapy and Pharmacology, 35(2), 149-152. https://doi.org/10.1007/BF00686638