Iron chelators of the di-2-pyridylketone thiosemicarbazone and 2-benzoylpyridine thiosemicarbazone series inhibit hiv-1 transcription: identification of novel cellular targets-iron, cyclin-dependent kinase (CDK) 2, and CDK9

Zufan Debebe, Tatyana Ammosova, Denitra Breuer, David B. Lovejoy, Danuta S. Kalinowski, Pradeep K. Karla, Krishna Kumar, Marina Jerebtsova, Patricio Ray, Fatah Kashanchi, Victor R. Gordeuk, Des R. Richardson, Sergei Nekhai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)


HIV-1 transcription is activated by HIV-1 Tat protein, which recruits cyclin-dependent kinase 9 (CDK9)/cyclin T1 and other host transcriptional coactivators to the HIV-1 promoter. Tat itself is phosphorylated by CDK2, and inhibition of CDK2 by small interfering RNA, the iron chelator 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), and the iron chelator deferasirox (ICL670) inhibits HIV-1 transcription. Here we have analyzed a group of novel di-2-pyridylketone thiosemicarbazone-and 2-benzoylpyridine thiosemicarbazone-based iron chelators that exhibit marked anticancer activity in vitro and in vivo (Proc Natl Acad Sci USA 103: 7670-7675, 2006; J Med Chem 50: 3716-3729, 2007). Several of these iron chelators, in particular 2-benzoylpyridine 4-allyl-3-thiosemicarbazone (Bp4aT) and 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT), inhibited HIV-1 transcription and replication at much lower concentrations than did 311 and ICL670. Neither Bp4aT nor Bp4eT were toxic after a 24-h incubation. However, longer incubations for 48 h or 72 h resulted in cytotoxicity. Analysis of the molecular mechanism of HIV-1 inhibition showed that the novel iron chelators inhibited basal HIV-1 transcription, but not the nuclear factor-kappa B-dependent transcription or transcription from an HIV-1 promoter with inactivated SP1 sites. The chelators inhibited the activities of CDK2 and CDK9/cyclin T1, suggesting that inhibition of CDK9 may contribute to the inhibition of HIV-1 transcription. Our study suggests the potential usefulness of Bp4aT or Bp4eT in antiretroviral regimens, particularly where resistance to standard treatment occurs.

Original languageEnglish
Pages (from-to)185-196
Number of pages12
JournalMolecular Pharmacology
Issue number1
Publication statusPublished - Jan 2011
Externally publishedYes

Bibliographical note

A correction exists for this article and can be found in Molecular Pharmacology (2011) Vol 80(6) p.1190 at DOI: 10.1124/mol.80.6.1190
This correction removed the author Pradeep K. Karla from the paper.



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