Glucocorticoid steroid hormones are routinely used in the treatment of steroid-responsive leukemia, such as T-cell acute lymphoblastic leukemia (ALL), multiple myeloma, and others. They are effective by triggering apoptosis (programmed cell death) in sensitive lymphoblasts. Successful therapy requires functional human glucocorticoid receptor (hGR), an intracellular protein that is a member of the nuclear steroid hormone receptor super-family. A critical step in the steroid pathway is the ligand-induced auto-up-regulation of the hGR itself. Our laboratory has discovered a new hGR promoter, termed 1A, which contains hormone- responsive sequences that mediate steroid stimulation of hGR gene transcription and protein expression. The central hypothesis of this proposal is that the regulation of transcription of the human glucocorticoid receptor (hGR) gene promoter causes alterations in the quantity of the hGR protein, and that this affects the sensitivity of the cell to the steroid hormone and the responsiveness of T-cell acute lymphoblastic leukemia (ALL) blasts to steroid therapy. The first specific aim is to elucidate the molecular mechanism of hGR stimulation of its own 1A promoter by determining the role of c-Myb and members of the c-Ets family of transcription factors (PU.1, Spi-B). The molecular mechanism(s)that distinguishes auto-up- and down- regulation of the hGR by hormone will be determined, and the role of the c-Myb and c-Ets proteins in causing hormone-mediated apoptosis in T-cell ALL will be assessed. The second specific aim will elucidate the molecular mechanism(s) by identifying the coregulators that contribute to both the auto-up-regulation and auto-down-regulation of hGR 1A promoter activity.. The third specific aim will assay the levels of hGR transcripts in samples from leukemia patients. A sensitive, ex vivo, hormone-challenge, RT-PCR assay will be developed in attempts to stratify leukemia patients into responders and resistant populations. This multifaceted translational approach will lead to an improved diagnosis and treatment of leukemia and a more rational approach to steroid therapy.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA116042-05
Application #
8015294
Study Section
Molecular and Cellular Endocrinology Study Section (MCE)
Program Officer
Howcroft, Thomas K
Project Start
2007-04-01
Project End
2013-01-31
Budget Start
2011-02-01
Budget End
2013-01-31
Support Year
5
Fiscal Year
2011
Total Cost
$235,535
Indirect Cost
Name
Louisiana State Univ Hsc New Orleans
Department
Biochemistry
Type
Schools of Medicine
DUNS #
782627814
City
New Orleans
State
LA
Country
United States
Zip Code
70112
Sarvaiya, Purvaba J; Schwartz, Jason R; Hernandez, Claudia P et al. (2012) Role of c-Myb in the survival of pre B-cell acute lymphoblastic leukemia and leukemogenesis. Am J Hematol 87:969-76
Schwartz, Jason R; Sarvaiya, Purvaba J; Leiva, Lily E et al. (2012) A facile, branched DNA assay to quantitatively measure glucocorticoid receptor auto-regulation in T-cell acute lymphoblastic leukemia. Chin J Cancer 31:381-91
Sarvaiya, Purvaba J; Schwartz, Jason R; Geng, Chuan-dong et al. (2012) c-Myb interacts with the glucocorticoid receptor and regulates its level in pre-B-acute lymphoblastic leukemia cells. Mol Cell Endocrinol 361:124-32
Geng, Chuan-dong; Vedeckis, Wayne V (2011) A new, lineage specific, autoup-regulation mechanism for human glucocorticoid receptor gene expression in 697 pre-B-acute lymphoblastic leukemia cells. Mol Endocrinol 25:44-57
Geng, Chuan-dong; Vedeckis, Wayne V (2010) Use of recombinant cell-permeable small peptides to modulate glucocorticoid sensitivity of acute lymphoblastic leukemia cells. Biochemistry 49:8892-901
Schwartz, Jason R; Sarvaiya, Purvaba J; Vedeckis, Wayne V (2010) Glucocorticoid receptor knock down reveals a similar apoptotic threshold but differing gene regulation patterns in T-cell and pre-B-cell acute lymphoblastic leukemia. Mol Cell Endocrinol 320:76-86
Geng, Chuan-dong; Schwartz, Jason R; Vedeckis, Wayne V (2008) A conserved molecular mechanism is responsible for the auto-up-regulation of glucocorticoid receptor gene promoters. Mol Endocrinol 22:2624-42