The hematopoietic stem cells (HSC) in the adult bone marrow (BM) maintain hematopoiesis by virtue of their unique self-renewal capacity. The self-renewal of HSC is at the heart of BM transplantation, a life-saving procedure in many hematological diseases. Self-renewal appears fundamentally different from proliferation, and requires unique extrinsic signals and intrinsic transcriptional regulators. During the first award cycle, we have identified zinc finger transcription factor Zfx as a novel specific regulator of adult HSC maintenance. Recent evidence suggests that many leukemias are propagated by rare leukemic stem cells (LSC), whereas other leukemia types appear more uniformly aggressive. In either case, the fundamental driving force of leukemia, and a prime target for therapy, is uncontrolled or misplaced self-renewal by leukemic cells. The regulators of normal HSC self-renewal are often """"""""hijacked"""""""" by leukemic cells including LSC to facilitate their self-renewal. Indeed, our preliminary results show that Zfx is required for leukemic cell development and/or propagation in several leukemia models. We propose that Zfx is an essential regulator of leukemic cell self-renewal, and as such represents an attractive candidate for future drug development. This hypothesis will be explored using three Specific Aims. First, the role of Zfx in the self-renewal of LSC population in vivo will be explored. Second, the requirement for Zfx in the propagation of aggressive leukemias without a distinct LSC compartment will be analyzed.
The third Aim will focus on the molecular mechanism of Zfx activity and its target genes in transformed hematopoietic cells. Altogether, these studies would elucidate a novel genetic pathway regulating self-renewal of leukemic cells, and provide candidates for future development of rational therapeutic approaches against leukemia.

Public Health Relevance

Blood cell cancers such as leukemias arise because blood cells acquire aberrant capacity for uncontrolled propagation, or self-renewal. We have identified a novel gene, Zfx, which appears important for leukemia development and propagation. Studies on the role and mechanism of action of Zfx in leukemia may provide novel therapeutic approaches to the disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL084353-07
Application #
8248227
Study Section
Molecular and Cellular Hematology (MCH)
Program Officer
Thomas, John
Project Start
2006-04-01
Project End
2015-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
7
Fiscal Year
2012
Total Cost
$397,539
Indirect Cost
$147,539
Name
Columbia University (N.Y.)
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032
Palmer, Colin J; Galan-Caridad, Jose M; Weisberg, Stuart P et al. (2014) Zfx facilitates tumorigenesis caused by activation of the Hedgehog pathway. Cancer Res 74:5914-24
Weisberg, Stuart P; Smith-Raska, Matthew R; Esquilin, Jose M et al. (2014) ZFX controls propagation and prevents differentiation of acute T-lymphoblastic and myeloid leukemia. Cell Rep 6:528-40
Harel, Sivan; Tu, Edmund Y; Weisberg, Stuart et al. (2012) ZFX controls the self-renewal of human embryonic stem cells. PLoS One 7:e42302
Arenzana, Teresita L; Smith-Raska, Matthew R; Reizis, Boris (2009) Transcription factor Zfx controls BCR-induced proliferation and survival of B lymphocytes. Blood 113:5857-67
Galan-Caridad, Jose M; Harel, Sivan; Arenzana, Teresita L et al. (2007) Zfx controls the self-renewal of embryonic and hematopoietic stem cells. Cell 129:345-57