Hepcidin, a key regulator of iron metabolism, is transcriptionally activated by p53

Authors

  • Orly Weizer-Stern,

    1. Cancer Research Centre and Lily and Edmond Safra Children's Hospital, Sheba Medical Centre and Sackler Medical School, Tel Aviv University, Tel Aviv
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  • Konstantin Adamsky,

    1. Cancer Research Centre and Lily and Edmond Safra Children's Hospital, Sheba Medical Centre and Sackler Medical School, Tel Aviv University, Tel Aviv
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  • Ofer Margalit,

    1. Cancer Research Centre and Lily and Edmond Safra Children's Hospital, Sheba Medical Centre and Sackler Medical School, Tel Aviv University, Tel Aviv
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  • Osnat Ashur-Fabian,

    1. Cancer Research Centre and Lily and Edmond Safra Children's Hospital, Sheba Medical Centre and Sackler Medical School, Tel Aviv University, Tel Aviv
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  • David Givol,

    1. Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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  • Ninette Amariglio,

    1. Cancer Research Centre and Lily and Edmond Safra Children's Hospital, Sheba Medical Centre and Sackler Medical School, Tel Aviv University, Tel Aviv
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  • Gideon Rechavi

    1. Cancer Research Centre and Lily and Edmond Safra Children's Hospital, Sheba Medical Centre and Sackler Medical School, Tel Aviv University, Tel Aviv
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Prof. Gideon Rechavi, Cancer Research Centre, Chaim Sheba Medical Centre, 52621 Tel-Hashomer, Israel. E-mail: gidi.rechavi@sheba.health.gov.il

Summary

Hepcidin is an iron-regulatory protein that is upregulated in response to increased iron or inflammatory stimuli. Hepcidin reduces serum iron and induces iron sequestration in the reticuloendothelial macrophages – the hallmark of anaemia of inflammation. Iron deprivation is used as a defense mechanism against infection, and it also has a beneficial effect on the control of cancer. The tumour-suppressor p53 transcriptionally regulates genes involved in growth arrest, apoptosis and DNA repair, and perturbation of p53 pathways is a hallmark of the majority of human cancers. This study inspected a role of p53 in the transcriptional regulation of hepcidin. Based on preliminary bioinformatics analysis, we identified a putative p53 response-element (p53RE) contained in the hepcidin gene (HAMP) promoter. Chromatin immunoprecipitation (ChIP), reporter assays and a temperature sensitive p53 cell-line system were used to demonstrate p53 binding and activation of the hepcidin promoter. p53 bound to hepcidin p53RE in vivo, andthis p53RE could confer p53-dependent transcriptional activation. Activation of p53 increased hepcidin expression, while silencing of p53 resulted in decreased hepcidin expression in human hepatoma cells. Taken together, these results define HAMP as a novel transcriptional target of p53. We hypothesise that hepcidin upregulation by p53 is part of a defence mechanism against cancer, through iron deprivation. Hepcidin induction by p53 might be involved in the pathogenesis of anaemia accompanying cancer.

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