The long-range goal of this research is to understand the mechanism of glucocorticosteroid action in lymphoid malignancy, providing information to guide development of novel therapeutic approaches. Glucocorticoids including prednisone and dexamethasone are among the most effective agents for treatment of lymphoid malignancies, but efficacy is limited by side effects and development of glucocorticoid resistance. Understanding the mechanism of glucocorticoid-induced apoptosis was the sole focus of this research until we recently discovered that glucocorticoids also induce autophagy. Remarkably glucocorticoids induce autophagy in lymphoma cells overexpressing the anti-apoptotic protein Bcl-2. Bcl-2 is elevated in the most common human lymphoid malignancies, including small lymphocytic lymphoma/chronic lymphocytic leukemia. Thus, our discovery that glucocorticoids induce autophagy in Bcl-2-positive lymphoma cells initiates an exciting new, clinically relevant, direction in our studies of glucocorticoid action in lymphoid malignancy. The goal is to understand fundamental mechanisms involved in induction of both apoptosis and autophagy by glucocorticoids.
The Specific Aim i s to investigate the role of key glucocorticoid-regulated genes, dig2/rtp801 and txnip, in the fundamental mechanism of glucocorticoid-induced apoptosis and autophagy, with the goal of identifying a common signaling pathway that leads to both of these processes.

Public Health Relevance

Glucocorticoid hormones, including prednisone and dexamethasone, are among the most effective agents for treatment of cancers of the lymphoid system, including acute and chronic lymphocytic leukemia and lymphoma. But their efficacy is limited by side effects and development of glucocorticoid resistance. The goal of this research is to understand the fundamental mechanism used by glucocorticoid hormones to kill leukemia and lymphoma cells, providing information to guide development of novel therapeutic approaches.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA042755-24
Application #
7876809
Study Section
Basic Mechanisms of Cancer Therapeutics Study Section (BMCT)
Program Officer
Mccarthy, Susan A
Project Start
1985-11-01
Project End
2011-08-31
Budget Start
2010-09-01
Budget End
2011-08-31
Support Year
24
Fiscal Year
2010
Total Cost
$325,827
Indirect Cost
Name
Case Western Reserve University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106
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Harr, Michael W; Rong, Yiping; Bootman, Martin D et al. (2009) Glucocorticoid-mediated inhibition of Lck modulates the pattern of T cell receptor-induced calcium signals by down-regulating inositol 1,4,5-trisphosphate receptors. J Biol Chem 284:31860-71
Rong, Yi-Ping; Barr, Paul; Yee, Vivien C et al. (2009) Targeting Bcl-2 based on the interaction of its BH4 domain with the inositol 1,4,5-trisphosphate receptor. Biochim Biophys Acta 1793:971-8
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