Characterization of Nuclear Retinoic Acid-Binding Activity in Sensitive Leukemic-Cell Lines - Cell-Specific Uptake of Atra and Rarα Protein Modulation

• Published in: Biochemical and biophysical research communications Vol. 213; no. 1; pp. 112 - 122
• Main Authors: Agadir, A., Cornic, M., Jerome, M., Menot, M.L., Cambier, N., Gaub, M.P., Gourmel, B., Lefebvre, P., Degos, L., Chomienne, C.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 04.08.1995
• Subjects: Animals; Antibodies; Antibodies, Monoclonal; Biological Transport; Blotting, Western; Cell Differentiation - drug effects; Cell Line; Cell Nucleus - metabolism; Cercopithecus aethiops; Electrophoresis, Polyacrylamide Gel; Flow Cytometry; Humans; Kinetics; Leukemia, Promyelocytic, Acute; Molecular Weight; Receptors, Retinoic Acid - analysis; Receptors, Retinoic Acid - isolation & purification; Receptors, Retinoic Acid - metabolism; Recombinant Proteins - analysis; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Retinoic Acid Receptor alpha; Transfection; Tretinoin - metabolism; Tretinoin - pharmacology; Tumor Cells, Cultured
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1995.2105

The diverse effects of all- trans retinoic acid (ATRA) on growth, differentiation and homeostasis of vertebrate organisms are mediated by three distinct isoforms of retinoic acid receptors (RARs), Although it is not known to what extent each RAR contributes to the different effects of ATRA, several studies have demonstrated that ATRA induced granulocytic differentiation in human myeloid leukemic cell lines is mediated by RARα. In this study, we investigated ATRA binding affinity of the endogenous nuclear receptors of HL-60 and NB4 leukemic cells, Scatchard plot analysis yielded an apparent dissociation constant of 5±0.3 nM and 1400±80 receptor sites per cell in HL-60 cells, whereas the NB4 promyelocytic leukemic cell line showed a lower affinity (8.5±0.5 nM and 900±30 receptor sites per cell). Modulation of RAR alpha protein (5 fold excess) was found in NB4 cells after 24 hours ATRA exposure, whereas HL-60 cells required a 72-hour culture period to weakly increase the RARα protein level These data were closely related to the ATRA intracellular concentration and kinetics of terminal differentiation of the cells.