Unravelling the Mechanism of DFO/DpT44mt-Induced Cell Death in breast cancer cells

ABSTRACT: Iron is required as a cofactor for many critical cellular enzymes involved in energy metabolism and cell proliferation and is thus essential for all living cells. To facilitate the rapid replication, the neoplastic cells have significantly higher levels of ribonucleotide reductase and the transferrin receptor 1 (TfR1) and many in vitro and in vivo studies have demonstrated that, compared to normal cells, cancer cells are more sensitive to iron (Fe) deprivation because of their marked Fe requirements. The higher Fe utilization by cancer cells provides a rationale for the selective antitumor activity of chelators. To date, Deferoxamine (DFO) is one of the most widely used iron chelator. In addition, DFO also has some antitumor activity. Moreover, novel chelators based on the di-2-pyridylketone thiosemicarbazone (DpT) scaffold, such as di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), induce iron sequestration and also form redox-active metal complexes that demonstrate potent and selective anti-tumor activity. Notably, Dp44mT and its analogs possess broad anti-cancer and anti-metastatic activity in vitro and in vivo against a variety of aggressive solid tumors. Understanding the mechanism of action of these ligands and their effect on the ER stress pathway will yield better clinical outcomes. It has been reported that iron depletion induced by Dp44mT and its metal complexes causes apoptosis by generating cytotoxic ROS and by inducing DNA strand breaks. The redox active complexes formed in lysosomes induce damages generating tumor cell cytotoxicity. The alterations in gene expression after iron depletion are complex. Moreover, in cultured cells Dp44mT resulted in marked up-regulation of the Fe-responsive tumor growth and metastasis suppressor Ndrg1 (N-myc downstream regulated gene-1). Therefore, Up-regulation of Ndrg1 may be another mechanism by which chelators inhibit cancer cell proliferation. Here we combine biochemistry, microscopy, flow cytometry and LC/MS-MS analyses to investigate cellular events induced by DFO and Dp44mT iron chelators on two human breast cancer cell lines, MDA-MB-231 and MDA-MB-157, in terms of proliferation, cell cycle, cytotoxicity and death. These experiments could potentially provide additional information in terms of the mechanism(s) of action of iron chelators in breast cancer cells.

INSTRUMENT(S): LTQ Orbitrap Velos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Breast Cancer Cell Line

DISEASE(S): Breast Cancer

SUBMITTER: gabriella tedeschi  

LAB HEAD: Gabriella Tedeschi

PROVIDER: PXD007595 | Pride | 2018-04-09

REPOSITORIES: Pride