title: Magnesium deprivation inhibits the expression of differentiation-related phenotypes in human promyelocytic leukemia HL-60 cells.
abstract: The role of magnesium ions in the differentiation of human promyelocytic leukemia HL-60 cells was investigated. When HL-60 extracellular magnesium was deficient (less than 0.01 mM), the total intracellular magnesium content and [3H] leucine incorporation rates decreased to 61 and 28%, respectively, on day 3. When the cells were treated with various inducers (100 nM 1 alpha, 25 dihydroxyitamine D3 (1,25(OH)2D3), 100 nM beta-all-trans retinoic acid (RA), 20 nM 12-o-tetradecanoyl phorbol-13-acetate (TPA), 1.25% dimethylsulfoxide (DMSO) and 30 nM aclacinomycin (AcM] in magnesium-deficient medium, the expression of differentiation-related phenotypes (nitroblue tetrazolium (NBT) reducing ability, nonspecific esterase (NSE) activity and monoclonal antibody, OKM1 binding activity) was almost completely inhibited. After a 2-day treatment with 100 nM 1,25(OH)2D3 in magnesium-deficient medium, the expression of differentiation-related phenotypes was restored by further incubation in the absence of inducer in standard magnesium medium (0.4 mM). These results suggested that magnesium deprivation inhibited the expression of HL-60 differentiation-related phenotypes but not their commitment to differentiation. These phenotypes were expressed without inducer in standard magnesium medium after a 2-day simultaneous treatment with 1,25(OH)2D3 and cyclohexamide (protein synthesis inhibitor) in magnesium-deficient medium, but not after simultaneous pretreatment with 1,25(OH)2D3 and alpha-amanitin (RNA synthesis inhibitor). Thus, it was suggested that the magnesium-requiring step in HL-60 cell differentiation is in protein but not mRNA synthesis. This conclusion is supported by the findings that changes in c-myc and c-fms mRNA levels in HL-60 cells treated with 100 nM 1,25(OH)2D3 in magnesium-deficient medium and those in standard magnesium medium were the same. In addition, dibutyryl cyclic adenosine monophosphate (dbc AMP) could restore expression of differentiation-related phenotypes inhibited by magnesium deprivation but not those inhibited by cyclohexamide, even though magnesium deprivation inhibited protein synthesis as much as did cyclohexamide. This suggests that magnesium-requiring step in HL-60 cell differentiation is different from that inhibited by cyclohexamide.
mesh_terms: D015250:Aclarubicin / Q000031:analogs & derivatives*; D000546:Amanitins / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004347:Drug Interactions; D006801:Humans; D007930:Leucine / Q000378:metabolism; D015470:Leukemia, Myeloid, Acute / Q000473:pathology*; D008275:Magnesium Deficiency / Q000503:physiopathology*; D009279:Naphthacenes / Q000494:pharmacology; D009857:Oncogenes / Q000187:drug effects; D010441:Peptide Chain Elongation, Translational; D010641:Phenotype; D012333:RNA, Messenger / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D000546:Amanitins; D009279:Naphthacenes; D012333:RNA, Messenger; C011157:aclacinomycins; D014212:Tretinoin; D003994:Bucladesine; D015250:Aclarubicin; D003513:Cycloheximide; D002117:Calcitriol; D007930:Leucine; D013755:Tetradecanoylphorbol Acetate; D004121:Dimethyl Sulfoxide