Inhibition of estrogen stimulated mitogenesis by 3-phenylacetylamino-2,6-piperidinedione and its Para-hydroxy analog

John A. Copland, Lawrence B. Hendry, Chung K. Chu, Joseph C. Wood, Robert W. Wrenn, Cooley G. Pantazis, Virendra B. Mahesh

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13 Scopus citations

Abstract

3-Phenylactetylamino-2,6-piperidinedione (A10) inhibited estradiol stimulated cell growth in the MCF-7 (E3) human breast tumor cell line in vivo and in vitro. While high concentrations of A10 were needed to inhibit cell proliferation (IC50 = 3 × 10-3 M in vitro), the compound demonstrated little toxicity. The effect appeared specific since a hydrolysis product of A10, phenylacetylglutamine, demonstrated no growth inhibitory activity at similar concentrations in MCF-7 (E3) cells in vitro. A computer designed analog, p-hydroxy A10, was more potent than A10 in inhibiting activity in MCF-7 (E3) cells in vitro. The IC50 for p-hydroxy A10 was 7 × 10-6 M which was comparable to that of the antiestrogen, tamoxifen (IC50 1 × 10-7 M). All three compounds caused a decline in estrogen receptor levels in a dose-dependent fashion. A10 also inhibited estradiol induction of progesterone receptors. Examination of protein kinase activity following an acute exposure to a 10-11 M growth stimulatory dose of estradiol revealed a 168% increase in protein kinase activity over that of untreated control cells. A10 in a dose-responsive fashion inhibited the estradiol stimulated increase in protein kinase activity. The protein kinase activity was also inhibited by p-hydroxy A10. These activities of A10 and p-hydroxy A10 coupled with the low toxicity and novelty of the basic A10 structure provide an exciting possibility of developing a new class of clinically useful antineoplastic drugs with minimal side effects.

Original languageEnglish (US)
Pages (from-to)451-462
Number of pages12
JournalJournal of Steroid Biochemistry and Molecular Biology
Volume46
Issue number4
DOIs
StatePublished - Oct 1993

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ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Endocrinology
  • Clinical Biochemistry
  • Cell Biology

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