Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.16.3.1 (ceruloplasmin)
 5,074 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of the metal ion binding rings-opened hydrolysis product of the anthracycline cardioprotective agent ICRF-187 [dexrazoxane; (+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane] to remove iron from transferrin and ferritin, and copper from ceruloplasmin was examined. ADR-925 completely removed Fe3+ from transferrin at below physiological pH but was unreactive at pH 7.4. ADR-925 slowly removed copper from ceruloplasmin at physiological pH (68% removal after 4.8 days). ADR-925 was capable of removing 18% of the iron from ferritin in 7.0 days. All of the metalloproteins displayed saturation behavior in their initial rates of metal ion removal by ADR-925. ICRF-187 may be, in part, preventing doxorubicin-induced cardiotoxicity by depleting iron and copper from these storage and transport proteins or by scavenging metal ions released from these proteins, thus inhibiting hydroxyl radical production by iron-doxorubicin complexes.
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PMID:The removal of metal ions from transferrin, ferritin and ceruloplasmin by the cardioprotective agent ICRF-187 [(+)-1,2-bis(3,5-dioxopiperazinyl-1-yl)propane] and its hydrolysis product ADR-925. 828 44

Doxorubicin is a potent cytostatic drug which is applied for the treatment of various kinds of malignant diseases. In spite of the routine use of this drug its major adverse effect, the dose-dependent cardiotoxicity, cannot be prevented yet. However, several clinical trials indicated that iron chelators are able to moderate the noxious effect more efficiently than radical scavenging antioxidants. This in turn supports the idea that doxorubicin-iron complexes are involved in triggering the cardiotoxicity of this drug by catalyzing the formation of oxygen radicals. However, both the mode of generation of doxorubicin-iron complexes and the consequences in vivo are not understood so far. In order to figure out whether or not doxorubicin can utilize iron from the transport protein transferrin for complex formation and prooxidative activities we studied the redox state of iron and its regulatory control by ceruloplasmin and ascorbate in the plasma of dogs suffering from malignant lymphoma by electron spin resonance spectroscopy. The respective electron spin resonance intensities prior to and after treatment with doxorubicin were compared with those from healthy controls. Our results revealed that dogs with lymphoma exhibit lower levels of paramagnetic copper in ceruloplasmin (-22%) and iron in transferrin (-33%) than healthy animals. Likewise the concentration of ascorbate radicals was lower in patients with lymphoma than in healthy subjects. The decreased cupric state of ceruloplasmin is equivalent to a diminished ferroxidase activity in plasma and therefore indicates indirectly an impaired antioxidant activity in these patients. Administration of doxorubicin in vivo further reduced the concentration of paramagnetic copper (-18%) and iron (-13%) while the concentration of ascorbate radicals remained unchanged. This decrease was also seen during the in vitro incubation of plasma with doxorubicin suggesting a direct interaction of the drug with the paramagnetic metal species. Model experiments revealed that the effect is based on a doxorubicin-induced release of iron from transferrin which is enhanced by ascorbate and the subsequent formation of doxorubicin-iron complexes. This mechanism was shown to trigger the formation of hydroxyl radicals from H(2)O(2) and to cause an oxidation of the antioxidant ceruloplasmin. Our data demonstrate that cardiotoxic doxorubicin-iron complexes are not only formed in cardiomyocytes itself as generally assumed, but are also present in the circulation. Therefore, these findings provide an additional rationale for potential benefit of iron chelators during doxorubicin chemotherapy.
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PMID:Paramagnetic species in the plasma of dogs with lymphoma prior to and after treatment with doxorubicin. An ESR study. 1244 62