Mitoxantrone mediates demethylation and reexpression of cyclin D2, estrogen receptor and 14.3.3σ in breast cancer cells

Belinda S. Parker, Suzanne M. Cutts, Abraham Nudelman, Ada Rephaeli, Don R. Phillips, Saraswati Sukumar

Research output: Contribution to journalArticlepeer-review

Abstract

In addition to its action as a topoisomerase II poison, mitoxantrone is activated by formaldehyde to bind DNA, forming DNA-adducts specifically at 5′CpA sequences, with an enhancement of adducts at methylated CpG sites. The butyric acid prodrug, AN-9 (pivaloyloxymethyl butyrate), releases formaldehyde upon cellular hydrolysis and our previous studies have shown that mitoxantrone acts synergistically with AN-9 in cytotoxicity assays. In this paper, we investigated the impact of methylation levels in the cell on mitoxantrone-induced cytotoxicity using the colon cancer cell line HCT116 and its derived DNA methyltransferase (DNMT) 1 and DNMT 3a knockout (DKO8) cell line. We found that decreased methylation levels in the DNMT-null cells led to at least a 2-fold reduction in mitoxantrone-induced cytotoxicity. Next, we studied the impact of mitoxantrone alone, and in combination with AN-9, on hypermethylated genes and their mRNA expression in breast cancer cells. Using methylation-specific PCR and RT-PCR, we found that mitoxantrone treatment of breast cancer cell lines resulted in demethylation of the 14.3.3σ, Cyclin D2 and ERα genes, followed by re-expression of their mRNA. The effect of mitoxantrone on re-expression of key genes involved in cell cycle regulation, and ensuing death of the cells may be an additional, previously undiscovered mechanism of action of mitoxantrone.

Original languageEnglish (US)
Pages (from-to)259-263
Number of pages5
JournalCancer Biology and Therapy
Volume2
Issue number3
DOIs
StatePublished - May 2003

Keywords

  • AN-9
  • Breast cancer
  • Gene expression
  • Methylation
  • Mitoxantrone

ASJC Scopus subject areas

  • Molecular Medicine
  • Oncology
  • Pharmacology
  • Cancer Research

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