title: Inhibitory effect of iron withdrawal by chelation on the growth of human and murine mammary carcinoma and fibrosarcoma cells.
abstract: Since iron uptake is essential for cell growth, rapidly dividing cancer cells are sensitive to iron depletion. To explore the effect of iron withdrawal on cancer cell growth, mouse and human mammary carcinoma cells (4T1 and MDA-MB-468, respectively) and mouse and human fibrosarcoma cells (L929 and HT1080, respectively) were cultured in the absence or presence of DIBI, a novel iron-chelating polymer containing hydroxypyridinone iron-ligand functionality. Cell growth was measured by a colorimetric assay for cell metabolic activity. DIBI-treated 4T1, MDA-MB-468, L929 and HT1080 cells, as well as their normal counterparts, showed a dose- and time-dependent reduction in growth that was selective for human cancer cells and mouse fibrosarcoma cells. The inhibitory effect of DIBI on fibrosarcoma and mammary carcinoma cell growth was reversed by addition of exogenous iron in the form of iron (III) citrate, confirming the iron selectivity of DIBI and that its inhibitory activity was iron-related. Fibrosarcoma and mammary carcinoma cell growth inhibition by DIBI was associated with S-phase cell cycle arrest and low to moderate levels of cell death by apoptosis. Consistent with apoptosis induction following DIBI-mediated iron withdrawal, fibrosarcoma and mammary carcinoma cells exhibited mitochondrial membrane permeabilization. A comparison of DIBI to other iron chelators showed that DIBI was superior to deferiprone and similar to or better than deferoxamine for inhibition of fibrosarcoma and mammary carcinoma cell growth. These findings suggest that iron withdrawal from the tumor microenvironment with a selective and potent iron chelator such as DIBI may prevent or inhibit tumor progression.
authors.affiliation: Department of Pathology, Dalhousie University, Halifax, NS, Canada.
authors.forename: Melanie R
authors.initials: MR
authors.lastname: Power Coombs
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
authors.forename: Taryn
authors.initials: T
authors.lastname: Grant
authors.affiliation: Department of Pathology, Dalhousie University, Halifax, NS, Canada.
authors.forename: Anna L
authors.initials: AL
authors.lastname: Greenshields
authors.affiliation: Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Arsenault
authors.affiliation: Chelation Partners Inc., Guelph, ON, Canada.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Holbein
authors.affiliation: Department of Pathology, Dalhousie University, Halifax, NS, Canada; Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada; Department of Surgery, Dalhousie University, Halifax, NS, Canada. Electronic address: d.w.hoskin@dal.ca.
authors.forename: David W
authors.initials: DW
authors.lastname: Hoskin
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D005260:Female; D005354:Fibrosarcoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007502:Iron Chelating Agents / Q000494:pharmacology*; D000090463:Iron Deficiencies; D015674:Mammary Neoplasms, Animal / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D014407:Tumor Cells, Cultured
chemical_list: D007502:Iron Chelating Agents
keywords: Apoptosis; Breast cancer; Cell cycle arrest; Fibrosarcoma; Iron chelation