Methyl and ethyl ketone analogs of salicylaldehyde isonicotinoyl hydrazone: Novel iron chelators with selective antiproliferative action
Graphical abstract
Highlights
► New analogs of aroylhydrazone iron chelator SIH examined for antiproliferative action. ► Higher toxicity observed towards the cancer cell lines compared to non-malignant cells. ► Dissipation of mitochondrial membrane potential, apoptosis, cell cycle arrest. ► Ethylketone-derived HPPI and nitro group-bearing NHAPI possessed the best properties.
Introduction
Iron (Fe) is an essential micronutrient for cellular proliferation. As part of the Fe-containing proteins it catalyses many biochemical reactions of vital importance for energy metabolism, cellular respiration or DNA synthesis [1], [2], [3]. Because of their uncontrolled proliferation, cancer cells have higher Fe requirement. Various studies demonstrated significantly increased Fe levels in malignant tumors compared to healthy tissue [4], [5]. In breast cancer, higher levels of Fe were associated with increased aggressiveness which may be related to enhanced expression of transferrin receptors (TfR) on the cell surface [6]. Indeed, estrogen stimulation of estrogen receptor-positive breast cancer cells results in higher transcription of TfR genes [7], [8]. In addition, it has been recently demonstrated that the excretion of Fe from breast cancer cells is decreased due to the reduction of excreting protein ferroportin [9]. Similarly, studies on acute lymphoblastic [10] or chronic granulocytic leukemia [11] noticed an increased level of serum Fe, which was significantly decreased during a remission of the disease. More recent evidence suggests that Fe chelators have considerable potential to inhibit the proliferation of leukemic cells [12], [13], [14] and also to induce their differentiation [15].
Salicylaldehyde isonicotinoyl hydrazone (SIH) is a tridentate aroylhydrazone chelator forming selectively 2:1 complexes with both Fe3+ and Fe2+ ions [16], [17]. Due to its small molecule and sufficient lipophilicity, SIH can be administered orally. Compared with other aroylhydrazones such as pyridoxal isonicotinoyl hydrazone (PIH) or 1-naphthaldehyde isonicotinoyl hydrazone (NIH), SIH has the most favorable lipophilic–hydrophilic properties for passing through membranes and that is why SIH is highly effective in transporting Fe ions away from cells [18]. Reported biological properties of SIH include the protection of guinea-pig or neonatal rat isolated cardiomyocytes, rat cardiomyoblast cell line H9c2 and retinal cell line ARPE-19 against the H2O2-induced cell injury [19], [20], [21], [22]. The good effectiveness of SIH was also noted in protection of H9c2 cardiomyoblasts against oxidative injury induced by tert-butyl hydroperoxide and catecholamines and/or their reactive intermediates [23], [24]. In addition, it has been recently shown as an effective radioprotective agent [25] and possessed protective potential at a mouse model of amyotrophic lateral sclerosis [26]. The treatment with Fe–SIH complexes has reduced the expression of viral proteins and RNA of hepatitis C virus [27]. High potential of this compound to protect against the cardiotoxicity of anthracycline daunorubicin is another positive effect of SIH. This was demonstrated both in vitro with isolated neonatal rat cardiomyocytes [28] and in vivo using chronic heart failure model in rabbits [29]. Interestingly, the in vitro study revealed that Fe chelation with SIH differently modulated the anthracycline toxicity to cardiac and cancer cells. At concentrations when SIH significantly reduced the daunorubicin toxicity to rat cardiomyocytes, it augmented the antiproliferative action of daunorubicin in HL-60 acute promyelocytic leukemia cell line [28]. Finally, low in vivo toxicity and good tolerability of SIH has been demonstrated following its 10-week repeated administration to rabbits [30].
Despite these promising pharmacodynamic properties, the pilot pharmacokinetic study of SIH has revealed rather short biological half-life of this substance following its single intravenous administration to rabbits, apparently due to its labile hydrazone bond which makes it prone to hydrolysis [31], [32], [33]. This property is apparently inherent for all aroylhydrazones derived from aromatic aldehydes [32]. Recently, new SIH analogs derived from aromatic ketones significantly more resistant against the hydrazone bond hydrolysis were designed and synthesized (Fig. 1) [34].
The aim of this study was to examine the toxic effects of these agents against proliferating cancer cells and compare them with SIH and a well-known siderophore deferoxamine (DFO) as reference agents. MCF-7 human breast adenocarcinoma and HL-60 human promyelocytic leukemia cells were used in this study as they represent in vitro models of both solid tumors and hematological malignancies. Selectivity of their toxicity against cancer cells was assessed by comparison with their toxicities towards non-cancerous H9c2 cardiomyoblasts. Following the initial screening, SIH and several promising new chelators with better selectivity towards cancer cells were further examined for their effects on cell cycle, mitochondrial destabilization and induction of apoptosis. More general aim of this work was to identify the design criteria for future improvement of antiproliferative potency of aroylhydrazone iron chelators.
Section snippets
Chemicals
Salicylaldehyde isonicotinoyl hydrazine (SIH) was synthesized as described previously [35]. (E)-N′-[1-(2-hydroxyphenyl)ethyliden] isonicotinoylhydrazide (HAPI), (E)-N′-[1-(2-hydroxyphenyl)propyliden] isonicotinoylhydrazide (HPPI), (E)-N′-[1-(2,4-dihydroxyphenyl)ethyliden] isonicotinoylhydrazide (2,4DHAPI), (E)-N′-[1-(2,6-dihydroxyphenyl)ethyliden] isonicotinoylhydrazide (2,6DHAPI), (E)-N′-[1-(2-hydroxy-4-methoxyphenyl)ethyliden] isonicotinoylhydrazide (MHAPI), (E)-N
Antiproliferative effects of Fe chelators
To assess the antiproliferative/cytotoxic effects of the studied chelators, cells were incubated with different concentrations of the aroylhydrazones for 72 h. MCF-7 human adenocarcinoma cell line was used as a model of solid tumors, while HL-60 human promyelocytic leukemia cell line served as a model of hematological malignity. The toxic effects of the chelators were also examined on the non-cancerous H9c2 cardiomyoblast cell line in order to assess degree of selectivity of their toxic actions
Discussion
Iron chelators have been successfully used in clinical practice for management of diseases associated with chronic body Fe overload, such as β-thalassemia major [40], [41]. In these diseases they promote Fe excretion and act as protectors against oxidative injury caused by free redox-active Fe – the key catalyst in the Fenton chemistry [42]. However, in the last decades, a new possible use of Fe chelators in medicine emerged as they have shown great potential in anticancer treatment [40], [41].
Conflict of interest statement
The authors declare no competing financial interests.
Acknowledgement
This study was supported by the Charles University (Projects GAUK 299511, SVV 265001, 265004, UNCE 33/2012).
References (70)
- et al.
Molecular control of vertebrate iron homeostasis by iron regulatory proteins
Biochim. Biophys. Acta
(2006) - et al.
The molecular mechanisms of the metabolism and transport of iron in normal and neoplastic cells
Biochim. Biophys. Acta
(1997) - et al.
Secretion of transferrin by human breast cancer cells
Biochem. Biophys. Res. Commun.
(1989) - et al.
Pyridoxal isonicotinoyl hydrazone analogs induce apoptosis in hematopoietic cells due to their iron-chelating properties
Biochem. Pharmacol.
(2003) - et al.
SIH – a novel lipophilic iron chelator – protects H9c2 cardiomyoblasts from oxidative stress-induced mitochondrial injury and cell death
J. Mol. Cell Cardiol.
(2005) - et al.
Iron chelation with salicylaldehyde isonicotinoyl hydrazone protects against catecholamine autoxidation and cardiotoxicity
Free Radic. Biol. Med.
(2011) - et al.
Iron inhibits replication of infectious hepatitis C virus in permissive Huh7.5.1 cells
J. Hepatol.
(2010) - et al.
Iron chelation-afforded cardioprotection against chronic anthracycline cardiotoxicity: a study of salicylaldehyde isonicotinoyl hydrazone (SIH)
Toxicology
(2007) - et al.
Hydrolysis of pyridoxal isonicotinoyl hydrazone and its analogs
Biochim. Biophys. Acta
(2003) - et al.
Investigation of the stability of aromatic hydrazones in plasma and related biological material
J. Pharm. Biomed. Anal.
(2008)
The potential of iron chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative agents
Blood
Cytotoxic chelators and chelates 1. Inhibition of DNA synthesis in cultured rodent and human cells by aroylhydrazones and by a copper(II) complex of salicylaldehyde benzoyl hydrazone.
Inorg. Chim. Acta
Dietary flavonoid apigenin is a potential inducer of intracellular oxidative stress: the role in the interruptive apoptotic signal
Arch. Biochem. Biophys.
Cancer cell iron metabolism and the development of potent iron chelators as anti-tumour agents
Biochim. Biophys. Acta
Role of ribonucleotide reductase in inhibition of mammalian cell growth by potent iron chelators
J. Biol. Chem.
The potential of iron chelators of the pyridoxal isonicotinoyl hydrazone class as effective antiproliferative agents, IV: the mechanisms involved in inhibiting cell-cycle progression
Blood
Cellular iron depletion stimulates the JNK and p38 MAPK signaling transduction pathways, dissociation of ASK1-thioredoxin, and activation of ASK1
J. Biol. Chem.
Iron chelation and regulation of the cell cycle: 2 mechanisms of posttranscriptional regulation of the universal cyclin-dependent kinase inhibitor p21CIP1/WAF1 by iron depletion
Blood
Tachpyridine, a metal chelator, induces G2 cell-cycle arrest, activates checkpoint kinases, and sensitizes cells to ionizing radiation
Blood
The iron-regulated metastasis suppressor, Ndrg-1: identification of novel molecular targets
Biochim. Biophys. Acta
Novel di-2-pyridyl-derived iron chelators with marked and selective antitumor activity: in vitro and in vivo assessment
Blood
The iron complex of Dp44mT is redox-active and induces hydroxyl radical formation: an EPR study
J. Inorg. Biochem.
Disorders of iron metabolism
N. Engl. J. Med.
Trace element concentration distributions in breast, lung and colon tissues
Phys. Med. Biol.
Levels of zinc, selenium, calcium, and iron in benign breast tissue and risk of subsequent breast cancer
Cancer Epidemiol. Biomarkers Prev.
Role of ferritin alterations in human breast cancer cells
Breast Cancer Res. Treat.
Estrogen regulation of transferrin gene expression in MCF-7 human breast cancer cells
J. Mol. Endocrinol.
Serum iron level in acute lymphoblastic leukaemia
Acta Paediatr. Acad. Sci. Hung
Iron stores in chronic granulocytic leukaemia at presentation
Scand. J. Haematol.
Iron chelation therapy with deferasirox induced complete remission in a patient with chemotherapy-resistant acute monocytic leukemia
Anticancer Res.
Antitumor activity and mechanism of action of the iron chelator, Dp44mT, against leukemic cells
Am. J. Hematol.
Effects of iron deprivation on multidrug resistance of leukemic K562 cells
Chemotherapy
Targeting iron homeostasis induces cellular differentiation and synergizes with differentiating agents in acute myeloid leukemia
J. Exp. Med.
Cited by (42)
Emerging role of ferroptosis in breast cancer: New dawn for overcoming tumor progression
2022, Pharmacology and TherapeuticsPromising Ag(I) complexes with N-acylhydrazones from aromatic aldehydes and isoniazid against multidrug resistance in tuberculosis
2021, Journal of Molecular StructurePatterns of cell death induced by metformin in human MCF-7 breast cancer cells
2020, Pathology Research and PracticeSynthesis and structural characterization of dinuclear Zinc(II) and Europium(III) complexes based on a bis-hydrazone ligand
2019, Journal of Molecular StructureCitation Excerpt :The coordination chemistry with zinc(II) and cobalt (II) ions have been studied [19]. The importance of this type of organic compounds as versatile building blocks for metal-mediated self-assembly and effective antimicrobial agents has been recognized two decades ago [28–32]. Here, we wish to extend the ligands to the C2-symmetrical bis-hydrazone containing multiple N, O-donating sites that allow effective metal binding with two or more metal centers.