1. c-Myb interacts with the glucocorticoid receptor and regulates its level in pre-B-acute lymphoblastic leukemia cells.
- Author
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Sarvaiya PJ, Schwartz JR, Geng CD, and Vedeckis WV
- Subjects
- Animals, Apoptosis drug effects, Cell Line, Tumor, Dexamethasone pharmacology, Doxycycline pharmacology, Gene Expression Regulation, Leukemic drug effects, Gene Knockdown Techniques, Humans, Mice, Precursor B-Cell Lymphoblastic Leukemia-Lymphoma genetics, Precursor B-Cell Lymphoblastic Leukemia-Lymphoma pathology, Promoter Regions, Genetic genetics, Protein Binding drug effects, RNA, Messenger genetics, RNA, Messenger metabolism, Receptors, Glucocorticoid genetics, Steroids pharmacology, Up-Regulation drug effects, Up-Regulation genetics, Precursor B-Cell Lymphoblastic Leukemia-Lymphoma metabolism, Proto-Oncogene Proteins c-myb metabolism, Receptors, Glucocorticoid metabolism
- Abstract
Glucocorticoid (GC) hormones are used in the treatment of hematopoietic malignancies. When the GC binds to the glucocorticoid receptor (GR) protein, c-Myb and GR are recruited at the Glucocorticoid Response Unit in the DNA. Here we demonstrate that c-Myb interacts with the GR and that decreasing c-Myb amounts reduces the levels of GR transcripts and protein in 697 pre-B-acute lymphoblastic leukemia (ALL) cells. Furthermore, the auto-upregulation of GR promoter 1C and promoter 1D is blunted at reduced c-Myb levels. Taken together, these data show that c-Myb is a direct, key regulator of the GR. Unexpectedly, the reduction in c-Myb levels increased the sensitivity of the cells to steroid-mediated apoptosis. This was because the reduction in c-Myb itself decreases cell viability, and the residual GR remained above the threshold needed to trigger apoptosis. These studies show the mutual importance of c-Myb and the GR in controlling survival of pre-B ALL cells., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2012
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