title: The potential of iron chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative agents II: the mechanism of action of ligands derived from salicylaldehyde benzoyl hydrazone and 2-hydroxy-1-naphthylaldehyde benzoyl hydrazone.
abstract: We have recently screened 36 analogues of the lipophilic iron (Fe) chelator, pyridoxal isonicotinoyl hydrazone (PIH), for their antiproliferative effect (Richardson et al, Blood 86:4295, 1995). Of these compounds, 1 chelator derived from salicylaldehyde benzoyl hydrazone (206) and 4 ligands derived from 2-hydroxy-1-naphthylaldehyde benzoyl hydrazone (308, 309, 311, and 315) showed pronounced antiproliferative activity, being far more effective than desferrioxamine (DFO). The present study was designed to investigate in detail the mechanism of action of these PIH analogues in a variety of neoplastic cell lines. This investigation showed that the analogues were far more active than DFO at inhibiting cellular proliferation and 3H-thymidine, 3H-leucine, and 3H-uridine incorporation. Additional experiments showed that, in contrast to DFO, the 5 analogues were potent at preventing 59Fe uptake from transferrin (Tf) and increasing 59Fe release from cells at concentrations as low as 10 micromol/L. Examination of the distribution of 59Fe in neoplastic cells using native polyacrylamide gel electrophoresis (PAGE)/59Fe-autoradiography showed that most of the 59Fe taken up from Tf was incorporated into ferritin, although 3 other previously unrecognized components (bands A, B, and C) were also identified. Band C comigrated with 59Fe-citrate and was chelated on incubation of neuroblastoma cells with DFO, PIH, or the PIH analogues, with this compartment being the main intracellular target of these ligands. Further work showed that the effects of the chelators at inducing characteristics consistent with apoptosis or necrosis were cell line-specific, and while DFO increased the percentage of cells in the G0/G1 phases in all cell types, the effect of analogue 311 on the cell cycle was variable depending on the cell line. This study provides further evidence for the potential use of these Fe chelators as anticancer agents.
authors.affiliation: Lady Davis Institute for Medical Research of the Sir Mortimer B. Davis-Jewish General Hospital, Montréal, Quebec, Canada.
authors.forename: D R
authors.initials: DR
authors.lastname: Richardson
authors.forename: K
authors.initials: K
authors.lastname: Milnes
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001547:Benzaldehydes / Q000737:chemistry* / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D053938:DNA Fragmentation; D003676:Deferoxamine / Q000494:pharmacology; D015195:Drug Design; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D005293:Ferritins / Q000378:metabolism; D006131:Growth Inhibitors / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D018922:HL-60 Cells / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D006835:Hydrazones / Q000737:chemistry* / Q000494:pharmacology; D007501:Iron / Q000378:metabolism; D007502:Iron Chelating Agents / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D007538:Isoniazid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D008024:Ligands; D015394:Molecular Structure; D009284:Naphthols / Q000737:chemistry* / Q000494:pharmacology; D009363:Neoplasm Proteins / Q000378:metabolism; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D011730:Pyridoxal / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D014168:Transferrin / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001547:Benzaldehydes; D006131:Growth Inhibitors; D006835:Hydrazones; D007502:Iron Chelating Agents; D008024:Ligands; D009284:Naphthols; D009363:Neoplasm Proteins; D014168:Transferrin; C073457:2-hydroxy-1-naphthylaldehyde benzoyl hydrazone; C073458:salicylaldehyde benzoyl hydrazone; D011730:Pyridoxal; C021079:pyridoxal isonicotinoyl hydrazone; D005293:Ferritins; D007501:Iron; D003676:Deferoxamine; D007538:Isoniazid