The anticancer drug Dp44mT inhibits T-cell activation and CD25 through a copper-dependent mechanism

Justin H. Gundelach, Ajay A. Madhavan, Peter J. Wettstein, Richard J. Bram

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


The di-2-pyridylketone thiosemicarbazone Dp44mT is a metal-chelating compound that has been demonstrated to have potent activity as an anticancer agent. Here we report that it also has a dramatic inhibitory effect on T-cell activation in vitro. We found that 10 nM Dp44mT (IC50 3.2 nM) prevented the up-regulation of surface CD25, and completely suppressed the activation and proliferation of splenic T cells isolated from Mus musculus that were stimulated with either T-cell receptor (TCR) cross-linking antibodies or phorbol ester plus ionomycin. In contrast, Dp44mT had no adverse effects on the survival of resting T cells. In addition, T cells stimulated in the presence of Dp44mT maintained the ability to upregulate CD69 surface expression and secrete interleukin-2. Consistent with these observations, Dp44mT did not inhibit multiple canonical signals downstream of the TCR, including the nuclear factor of activated T cells. The effects of Dp44mT were easily mitigated by addition of nontoxic copper chelators or N-acetylcysteine, indicating a role for copper and reactive oxygen species in its actions. Together, these findings suggest that Dp44mT may serve as a potent immunosuppressive agent that could complicate its use as a cancer therapeutic agent, but might have utility in the treatment of autoimmunity.

Original languageEnglish (US)
Pages (from-to)782-792
Number of pages11
JournalFASEB Journal
Issue number2
StatePublished - Feb 2013


  • CD69
  • Chemotherapy
  • IL-2
  • Immune suppression

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics


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