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Further elucidation of mechanism of resistance to vincristine in myeloid cells: role of hypochlorous acid in degradation of vincristine by myeloperoxidase.
- Source :
-
Leukemia [Leukemia] 2000 Jan; Vol. 14 (1), pp. 47-51. - Publication Year :
- 2000
-
Abstract
- Inherent resistance of myeloblasts to vincristine (VCR) has been related to the activity of myeloperoxidase (MPO) which can degrade VCR in the presence of hydrogen peroxide (H2O2). We investigated the relationship between VCR degradation and hypochlorous acid (HOCl) generation from the reaction of H2O2 with chlorine (Cl) as catalyzed by MPO. A cell-free system, three human leukemia cell lines (CEM/CCRF, HL-60, U937) and 15 bone marrow samples from children with acute myeloid leukemia (AML) were studied. VCR cytotoxicity was evaluated by MTT assay and by quantitative measurement of apoptosis. In vitro levels of VCR in cell-free systems were measured by high performance liquid chromatography (HPLC), and intracellular HOCl levels by oxidation of 5-thio-2-nitrobenzoic acid with the accompanying decrease in the absorbency at 412 nm. VCR was degraded by increasing concentrations of HOCl in cell-free systems and this activity was inhibited by taurine, which is known to block HOCl activity. This finding was confirmed by the VCR cytotoxicity studies on cell lines. The HOCl-producing myeloblasts from patients were resistant to VCR. In five samples out of eight HOCl was also detected extracellularly. These results suggest that oxidation by HOCl may be the final step in VCR degradation catalyzed by MPO through its action on intracellular H2O2 and Cl. Leukemia (2000) 14, 47-51.
- Subjects :
- Acute Disease
Antineoplastic Agents, Phytogenic metabolism
Bone Marrow Cells enzymology
Bone Marrow Cells metabolism
Humans
Leukemia, Myeloid metabolism
Tumor Cells, Cultured
Vincristine metabolism
Antineoplastic Agents, Phytogenic pharmacology
Bone Marrow Cells drug effects
Drug Resistance, Neoplasm
Hypochlorous Acid metabolism
Leukemia, Myeloid pathology
Peroxidase metabolism
Vincristine pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0887-6924
- Volume :
- 14
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Leukemia
- Publication Type :
- Academic Journal
- Accession number :
- 10637476
- Full Text :
- https://doi.org/10.1038/sj.leu.2401627