Modulator inhibits nuclear translocation of the glucocorticoid receptor and inhibits glucocorticoid-induced apoptosis in the human leukemic cell line CEM C-7.
Modulator is an endogenous low-molecular-weight regulator of both glucocorticoid and mineralocorticoid receptors as well as protein kinase C. Structural analysis of modulator purified to apparent homogeneity suggests that it is a novel ether aminophosphoglyceride. In this report, we show that modulator inhibits cytosolic human glucocorticoid receptor (GR) complex activation as measured by DNA-cellulose binding. In addition, modulator blocks glucocorticoid-induced nuclear translocation of the GR in intact human leukemic (CEM C-7) cells, as illustrated by immunocytochemical localization. Furthermore, we demonstrate that modulator, by blocking the activation and subsequent translocation of GR, inhibits glucocorticoid-mediated apoptosis, characterized by chromatin condensation, internucleosomal DNA fragmentation, and cell death in glucocorticoid-sensitive CEM C-7 cells. Modulator inhibits glucocorticoid-induced c-myc gene repression and glucocorticoid receptor gene up-regulation. These data suggest that modulator functions to regulate the GR in intact cells as well as in cytosolic preparations. In addition, the inhibition of glucocorticoid-induced programmed cell death by modulator sheds light on the cellular function of modulator as well as on the mechanism by which apoptosis occurs in CEM C-7 cells.
Robertson
N M
NM
Department of Pharmacology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Bodine
P V
PV
Hsu
T C
TC
Alnemri
E S
ES
Litwack
G
G
D000595:Amino Acid Sequence; D000906:Antibodies; D000918:Antibody Specificity; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002470:Cell Survival; D002482:Cellulose / Q000031:analogs & derivatives; D002846:Chromatography, Affinity; D003600:Cytosol / Q000378:metabolism; D004247:DNA; D004273:DNA, Neoplasm / Q000302:isolation & purification; D005434:Flow Cytometry; D016259:Genes, myc; D006801:Humans; D015151:Immunoblotting; D007700:Kinetics; D007938:Leukemia; D008214:Lymphocytes; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D011965:Receptors, Glucocorticoid / Q000302:isolation & purification / Q000378:metabolism*; D014222:Triamcinolone Acetonide / Q000378:metabolism / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
D000906:Antibodies; D004273:DNA, Neoplasm; C033190:DNA-cellulose; D010455:Peptides; D011965:Receptors, Glucocorticoid; C039250:triamcinolone acetonide receptor; D002482:Cellulose; D004247:DNA; D014222:Triamcinolone Acetonide