Most cited article - PubMed ID 14965167
A study of potential toxic effects after repeated 10-week administration of a new iron chelator--salicylaldehyde isonicotinoyl hydrazone (SIH) to rabbits
Salicylaldehyde isonicotinoyl hydrazone (SIH) is an intracellular iron chelator with well documented potential to protect against oxidative injury both in vitro and in vivo. However, it suffers from short biological half-life caused by fast hydrolysis of the hydrazone bond. Recently, a concept of boronate prochelators has been introduced as a strategy that might overcome these limitations. This study presents two complementary analytical methods for detecting the prochelator-boronyl salicylaldehyde isonicotinoyl hydrazone-BSIH along with its active metal-binding chelator SIH in different solution matrices and concentration ranges. An LC-UV method for determination of BSIH and SIH in buffer and cell culture medium was validated over concentrations of 7-115 and 4-115 μM, respectively, and applied to BSIH activation experiments in vitro. An LC-MS assay was validated for quantification of BSIH and SIH in plasma over the concentration range of 0.06-23 and 0.24-23 μM, respectively, and applied to stability studies in plasma in vitro as well as analysis of plasma taken after i.v. administration of BSIH to rats. A Zorbax-RP bonus column and mobile phases containing either phosphate buffer with EDTA or ammonium formate and methanol/acetonitrile mixture provided suitable conditions for the LC-UV and LC-MS analysis, respectively. Samples were diluted or precipitated with methanol prior to analysis. These separative analytical techniques establish the first validated protocols to investigate BSIH activation by hydrogen peroxide in multiple matrices, directly compare the stabilities of the prochelator and its chelator in plasma, and provide the first basic pharmacokinetic data of this prochelator. Experiments reveal that BSIH is stable in all media tested and is partially converted to SIH by H2O2. The observed integrity of BSIH in plasma samples from the in vivo study suggests that the concept of prochelation might be a promising strategy for further development of aroylhydrazone cytoprotective agents.
- Keywords
- Aroylhydrazone, Boronyl salicylaldehyde isonicotinoyl hydrazone, Pharmacokinetics, Prochelator salicylaldehyde isonicotinoyl hydrazone, Stability,
- MeSH
- Aldehydes analysis blood MeSH
- Chelating Agents analysis MeSH
- Chromatography, Liquid methods MeSH
- Mass Spectrometry methods MeSH
- Hydrazones analysis blood MeSH
- Culture Media chemistry MeSH
- Boronic Acids analysis blood MeSH
- Isonicotinic Acids analysis blood MeSH
- Molecular Structure MeSH
- Rats, Wistar MeSH
- Reference Standards MeSH
- Sensitivity and Specificity MeSH
- Spectrophotometry, Ultraviolet methods MeSH
- Drug Stability MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
- Names of Substances
- (isonicotinic acid (2-(4,4,5,5-tetramethyl-(1,3,2)dioxaborolan-2-yl)benzylidene)hydrazide) MeSH Browser
- Aldehydes MeSH
- Chelating Agents MeSH
- Hydrazones MeSH
- Culture Media MeSH
- Boronic Acids MeSH
- Isonicotinic Acids MeSH
- salicylaldehyde isonicotinoyl hydrazone MeSH Browser
Salicylaldehyde isonicotinoyl hydrazone (SIH) is a lipophilic, tridentate iron chelator with marked anti-oxidant and modest cytotoxic activity against neoplastic cells. However, it has poor stability in an aqueous environment due to the rapid hydrolysis of its hydrazone bond. In this study, we synthesized a series of new SIH analogs (based on previously described aromatic ketones with improved hydrolytic stability). Their structure-activity relationships were assessed with respect to their stability in plasma, iron chelation efficacy, redox effects and cytotoxic activity against MCF-7 breast adenocarcinoma cells. Furthermore, studies assessed the cytotoxicity of these chelators and their ability to afford protection against hydrogen peroxide-induced oxidative injury in H9c2 cardiomyoblasts. The ligands with a reduced hydrazone bond, or the presence of bulky alkyl substituents near the hydrazone bond, showed severely limited biological activity. The introduction of a bromine substituent increased ligand-induced cytotoxicity to both cancer cells and H9c2 cardiomyoblasts. A similar effect was observed when the phenolic ring was exchanged with pyridine (i.e., changing the ligating site from O, N, O to N, N, O), which led to pro-oxidative effects. In contrast, compounds with long, flexible alkyl chains adjacent to the hydrazone bond exhibited specific cytotoxic effects against MCF-7 breast adenocarcinoma cells and low toxicity against H9c2 cardiomyoblasts. Hence, this study highlights important structure-activity relationships and provides insight into the further development of aroylhydrazone iron chelators with more potent and selective anti-neoplastic effects.
- MeSH
- Aldehydes chemistry pharmacology toxicity MeSH
- Antioxidants chemistry pharmacology MeSH
- Cell Line MeSH
- Iron Chelating Agents chemistry pharmacology MeSH
- Hydrazones chemistry pharmacology toxicity MeSH
- Humans MeSH
- MCF-7 Cells MeSH
- Myoblasts drug effects MeSH
- Oxidative Stress drug effects MeSH
- Hydrogen Peroxide toxicity MeSH
- Antineoplastic Agents chemistry toxicity MeSH
- Structure-Activity Relationship MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Aldehydes MeSH
- Antioxidants MeSH
- Iron Chelating Agents MeSH
- Hydrazones MeSH
- Hydrogen Peroxide MeSH
- Antineoplastic Agents MeSH
- salicylaldehyde isonicotinoyl hydrazone MeSH Browser
Oxidative stress is a common denominator of numerous cardiovascular disorders. Free cellular iron catalyzes the formation of highly toxic hydroxyl radicals, and iron chelation may thus be an effective therapeutic approach. However, using classical iron chelators in diseases without iron overload poses risks that necessitate more advanced approaches, such as prochelators that are activated to chelate iron only under disease-specific oxidative stress conditions. In this study, three cell-membrane-permeable iron chelators (clinically used deferasirox and experimental SIH and HAPI) and five boronate-masked prochelator analogs were evaluated for their ability to protect cardiac cells against oxidative injury induced by hydrogen peroxide. Whereas the deferasirox-derived agents TIP and TRA-IMM displayed negligible protection and even considerable toxicity, the aroylhydrazone prochelators BHAPI and BSIH-PD provided significant cytoprotection and displayed lower toxicity after prolonged cellular exposure compared to their parent chelators HAPI and SIH, respectively. Overall, the most favorable properties in terms of protective efficiency and low inherent cytotoxicity were observed with the aroylhydrazone prochelator BSIH. BSIH efficiently protected both H9c2 rat cardiomyoblast-derived cells and isolated primary rat cardiomyocytes against hydrogen peroxide-induced mitochondrial and lysosomal dysregulation and cell death. At the same time, BSIH was nontoxic at concentrations up to its solubility limit (600 μM) and in 72-h incubation. Hence, BSIH merits further investigation for prevention and/or treatment of cardiovascular disorders associated with a known (or presumed) component of oxidative stress.
- Keywords
- BSIH, Deferasirox, Free radicals, ICL670A, Iron chelation, Prochelator, Salicylaldehyde isonicotinoyl hydrazone,
- MeSH
- Aldehydes chemistry pharmacology MeSH
- Apoptosis drug effects MeSH
- Benzoates chemistry pharmacology MeSH
- Cell Line MeSH
- Iron Chelating Agents chemistry pharmacology MeSH
- Cytoprotection * MeSH
- Deferasirox MeSH
- Hydrazones chemistry pharmacology MeSH
- Myocytes, Cardiac drug effects physiology MeSH
- Rats MeSH
- Boronic Acids chemistry pharmacology MeSH
- Isonicotinic Acids chemistry pharmacology MeSH
- Membrane Potential, Mitochondrial drug effects MeSH
- Oxidative Stress drug effects MeSH
- Cell Membrane Permeability drug effects MeSH
- Hydrogen Peroxide metabolism MeSH
- Rats, Wistar MeSH
- Semicarbazones chemistry pharmacology MeSH
- Boron Compounds chemistry pharmacology MeSH
- Mitochondria, Heart drug effects physiology MeSH
- Triazoles chemistry pharmacology MeSH
- Iron chemistry metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, N.I.H., Extramural MeSH
- Comparative Study MeSH
- Names of Substances
- (isonicotinic acid (2-(4,4,5,5-tetramethyl-(1,3,2)dioxaborolan-2-yl)benzylidene)hydrazide) MeSH Browser
- Aldehydes MeSH
- Benzoates MeSH
- Iron Chelating Agents MeSH
- Deferasirox MeSH
- Hydrazones MeSH
- Boronic Acids MeSH
- Isonicotinic Acids MeSH
- N'-(1-(2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyloxy)phenyl)ethylidene)isonicotinohydrazide MeSH Browser
- Hydrogen Peroxide MeSH
- salicylaldehyde isonicotinoyl hydrazone MeSH Browser
- Semicarbazones MeSH
- Boron Compounds MeSH
- Triazoles MeSH
- Iron MeSH
BACKGROUND AND PURPOSE: The clinical utility of anthracycline antineoplastic drugs is limited by the risk of cardiotoxicity, which has been traditionally attributed to iron-mediated production of reactive oxygen species (ROS). EXPERIMENTAL APPROACH: The aims of this study were to examine the strongly lipophilic iron chelator, salicylaldehyde isonicotinoyl hydrazone (SIH), for its ability to protect rat isolated cardiomyocytes against the toxicity of daunorubicin (DAU) and to investigate the effects of SIH on DAU-induced inhibition of proliferation in a leukaemic cell line. Cell toxicity was measured by release of lactate dehydrogenase and staining with Hoechst 33342 or propidium iodide and lipid peroxidation by malonaldehyde formation. KEY RESULTS: SIH fully protected cardiomyocytes against model oxidative injury induced by hydrogen peroxide exposure. SIH also significantly but only partially and with no apparent dose-dependency, reduced DAU-induced cardiomyocyte death. However, the observed protection was not accompanied by decreased lipid peroxidation. In the HL-60 acute promyelocytic leukaemia cell line, SIH did not blunt the antiproliferative efficacy of DAU. Instead, at concentrations that reduced DAU toxicity to cardiomyocytes, SIH enhanced the tumoricidal action of DAU. CONCLUSIONS AND IMPLICATIONS: This study demonstrates that iron is most likely involved in anthracycline cardiotoxicity and that iron chelation has protective potential, but apparently through mechanism(s) other than by inhibition of ROS-induced injury. In addition to cardioprotection, iron chelation may have considerable potential to improve the therapeutic action of anthracyclines by enhancing their anticancer efficiency and this potential warrants further investigation.
- MeSH
- Leukemia, Promyelocytic, Acute metabolism pathology MeSH
- Aldehydes pharmacology MeSH
- Time Factors MeSH
- Iron Chelating Agents pharmacology MeSH
- Cytoprotection MeSH
- Daunorubicin toxicity MeSH
- HL-60 Cells MeSH
- Hydrazones pharmacology MeSH
- Myocytes, Cardiac drug effects metabolism pathology MeSH
- Rats MeSH
- Humans MeSH
- Malondialdehyde metabolism MeSH
- Animals, Newborn MeSH
- Oxidative Stress drug effects MeSH
- Lipid Peroxidation drug effects MeSH
- Rats, Wistar MeSH
- Cell Proliferation drug effects MeSH
- Antibiotics, Antineoplastic toxicity MeSH
- Cell Survival drug effects MeSH
- Dose-Response Relationship, Drug MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Aldehydes MeSH
- Iron Chelating Agents MeSH
- Daunorubicin MeSH
- Hydrazones MeSH
- Malondialdehyde MeSH
- Antibiotics, Antineoplastic MeSH
- salicylaldehyde isonicotinoyl hydrazone MeSH Browser