ATRA promotes alpha tocopherol succinate-induced apoptosis in freshly isolated leukemic cells from chronic myeloid leukemic patients

• Published in: Molecular and cellular biochemistry 2008-01, Vol.307 (1-2), p.109-119
• Main Authors: Kumar, Surender, Khanduja, Krishan Lal, Verma, Neelam, Verma, Subhash C, Avti, Pramod Kumar, Pathak, Chander Mohan
• Format: Article
• Language: English
• Subjects: Adult; All-trans retinoic acid; Antineoplastic Combined Chemotherapy Protocols - therapeutic use; Apoptosis; Apoptosis - drug effects; Biochemistry; Biomedical and Life Sciences; Cardiology; Caspase 3 - metabolism; Cell Separation; Cell Survival - drug effects; Cellular biology; Chronic myeloid leukemia; Combined treatment; Cytotoxicity; DNA fragmentation; DNA Fragmentation - drug effects; Drug Evaluation, Preclinical; Drug Synergism; Female; Free radicals; Humans; In Vitro Techniques; Leukemia; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - drug therapy; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - metabolism; Life Sciences; Lipid Peroxidation - drug effects; Lysosomes - drug effects; Male; Medical Biochemistry; Membrane Potential, Mitochondrial - drug effects; Middle Aged; Nitric oxide; Oncology; Peroxidation; Tocopherols; Tretinoin - administration & dosage; Tretinoin - pharmacology; Vitamin E - administration & dosage; Vitamin E - analogs & derivatives; Vitamin E - pharmacology; α-Tocopherol succinate
• ISSN: 0300-8177; 1573-4919
• DOI: 10.1007/s11010-007-9590-7

We investigated the in vitro efficacy of all-trans retinoic acid (ATRA) and alpha-tocopherol succinate (α-TS) alone and in combination on the induction of cell death in freshly isolated leukemic cells obtained from chronic myeloid leukemia (CML) patients. In vitro cytotoxicity and induction of lipid peroxidation by ATRA (10 μM) and α-TS (25 or 50 μM) were evaluated in primary leukemic cells by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and malondialdehyde formation respectively. Treatment of leukemic cells with α-TS alone or in combination with ATRA significantly (P < 0.05) decreased the cell viability in a concentration and time dependent manner as compared to peripheral blood mononuclear cells obtained from normal healthy controls. Lipid peroxidation was enhanced by 98% (P < 0.05) on combined treatment of cells with ATRA (10 μM) and α-TS (50 μM). ATRA alone did not enhance the externalization of phosphatidyl serine as studied by annexin-V binding using fluorescence activated cell sorter analysis, whereas in combination with α-TS it increased to 400% at 12 h. The treatment of leukemic cells to combination of ATRA with α-TS significantly decreased (P < 0.05) mitochondrial membrane potential and enhanced lysosomal destabilization. The combination of these drugs also increased mitochondrial and cytosolic reactive oxygen species (ROS) production, nitric oxide levels, and caspase-3 activity significantly and caused DNA fragmentation at 24 h in a concentration dependent manner in the leukemic cells. Our data suggest that ATRA in combination with α-TS efficiently induces apoptosis in leukemic cells, which may be a useful therapeutic modality in CML patients.