1,25-Dihydroxyvitamin D3 regulation of phorbol ester receptors in HL-60 leukemia cells.

Abstract

In this study the relationship between cell binding of phorbol 12,13-dibutyrate (PDBu) and induction of differentiation by 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) was examined. Binding of [3H]PDBu increased within 12 h of 1,25-(OH)2D3 treatment, and a 60-130% increase in [3H]PDBu receptor levels was observed within 24 h. By 48 h, however, [3H]PDBu binding was not different from control. Scatchard analysis of [3H]PDBu binding showed no statistical differences in Kd value (Kd approximately equal to 30 nM) between 1,25-(OH)2D3-treated and control cells 22 h post-treatment; however, a 2-fold increase in Bmax was observed in treated (338 +/- 24 pmol/10(9) cells) compared to control cultures (170 +/- 14 pmol/10(9) cells). Stimulation of [3H]PDBu binding was dependent on 1,25-(OH)2D3 concentrations over a range of 1-100 nM. Homogenates from 1,25-(OH)2D3-treated HL-60 cells also demonstrated an increase (70%) in [3H]PDBu binding to the Ca2+/phospholipid-dependent enzyme protein kinase C as assessed by incubation of cell homogenates with [3H]PDBu in the presence of saturating phosphatidylserine and calcium concentrations. This suggests that the increase in [3H]PDBu binding cannot be entirely explained by modulation of the latter two agents. Cycloheximide (5 microM), an inhibitor of protein synthesis, ablated the 1,25-(OH)2D3-stimulated increase in [3H]PDBu binding to intact HL-60 cells. These data demonstrate that an increase in [3H]PDBu binding occurs early in the course of 1,25-(OH)2D3-induced differentiation, results from an increased number of [3H]PDBu-binding site, and is dependent on protein synthesis.

• Authors: R E Martell, R U Simpson, J M Taylor
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 262 Issue 12 Pg. 5570-5 (Apr 25 1987) ISSN: 0021-9258 [Print] United States
• PMID: 3471756 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Caenorhabditis elegans Proteins
• Carrier Proteins
• Phorbol Esters
• Receptors, Drug
• Receptors, Immunologic
• phorbol ester binding protein
• phorbol ester receptor
• Phorbol 12,13-Dibutyrate
• Protein Kinase C
• Calcitriol

Topics

• Caenorhabditis elegans Proteins
• Calcitriol (pharmacology)
• Carrier Proteins
• Cell Line
• Humans
• Kinetics
• Leukemia, Myeloid, Acute
• Phorbol 12,13-Dibutyrate
• Phorbol Esters (metabolism)
• Protein Kinase C
• Receptors, Drug
• Receptors, Immunologic (drug effects, metabolism)