Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis and decreased blood counts. We have shown that the p38 MARK pathway is constitutively activated in MDS bone marrows and plays a role in the increased apoptosis seen in hematopoietic progenitors. Most importantly, pharmacological inhibition of p38 leads to increased hematopoietic colony formation from primary MDS CD34+ hematopoietic progenitors and leads to enhanced hematopoiesis in a variety of MDS subtypes in vitro. This proposal will define the pathophysiological role that p38 plays in MDS, and will identify its molecular and cellular targets.
Specific Aim 1 will determine whether constitutive p38 activation results in ineffective hematopoiesis in MDS. We will selectively inhibit the expression of the various p38 isoforms (alpha, beta, gamma, delta) in CD34+ cells from MDS bone marrows and examine the effects of such inhibition on hematopoietic progenitor colony formation and apoptosis. The effects of adenoviral-mediated overexpression of various isoform-specific dominant negative mutants on hematopoietic progenitor cell growth will also be assessed. The effects seen will be correlated with various MDS subtypes and clinical characteristics.
Specific Aim 2 will study the mechanisms of constitutive activation of p38 in MDS and identify its downstream effectors. Biochemical, immunohistochemical and flow cytometric methodologies will be used to examine the activation of putative upstream and downstream effectors in bone marrow-derived hematopoietic progenitors. These will include evaluation of the activation status of the small G-protein Rac1 and the upstream Map kinase kinases, MKK3, MKK6 and MKK4, as well as the activation of the downstream effectors MapKapK-2, MapKapK-3, and Msk1. siRNA-mediated knockdown of kinases found constitutively activated will be subsequently used to determine the functional relevance of each one of them in MDS hematopoiesis. Bone marrow microenvironment can also contribute to the pathophysiology of MDS by being involved in cytokine secretion. Thus, Specific Aim 3 is to examine whether activation of p38 MARK mediates overproduction of myelosuppressive cytokines in MDS bone marrows. We will examine whether p38 inhibitors suppress the overproduction of TNFalpha and IFNgamma by infiltrating macrophages and lymphocytes in the bone marrows of MDS patients. We will also evaluate IL-6 and VEGF production by MDS marrow derived stromal cells as compared to normal stromal cells and assess the effects of p38 inhibitors on such production. Altogether, these studies should provide valuable information on the role of p38 MARK pathway in the pathogenesis of MDS. Moreover, the results of these studies should be of direct clinical-translational relevance and lead to the development of novel therapeutic approaches for the treatment of MDS, including clinical trials with clinically relevant pharmacological inhibitors of p38 pathway such as SCIO-469.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL082946-03
Application #
7283566
Study Section
Special Emphasis Panel (ZHL1-CSR-I (S1))
Program Officer
Di Fronzo, Nancy L
Project Start
2005-09-30
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2008-06-30
Support Year
3
Fiscal Year
2007
Total Cost
$383,539
Indirect Cost
Name
Albert Einstein College of Medicine
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
110521739
City
Bronx
State
NY
Country
United States
Zip Code
10461
Heuck, Christoph J; Mehta, Jayesh; Bhagat, Tushar et al. (2013) Myeloma is characterized by stage-specific alterations in DNA methylation that occur early during myelomagenesis. J Immunol 190:2966-75
Bhagat, Tushar D; Zhou, Li; Sokol, Lubomir et al. (2013) miR-21 mediates hematopoietic suppression in MDS by activating TGF-? signaling. Blood 121:2875-81
Nischal, Sangeeta; Bhattacharyya, Sanchari; Christopeit, Maximilian et al. (2013) Methylome profiling reveals distinct alterations in phenotypic and mutational subgroups of myeloproliferative neoplasms. Cancer Res 73:1076-85
Will, Britta; Zhou, Li; Vogler, Thomas O et al. (2012) Stem and progenitor cells in myelodysplastic syndromes show aberrant stage-specific expansion and harbor genetic and epigenetic alterations. Blood 120:2076-86
Alvarez, Hector; Opalinska, Joanna; Zhou, Li et al. (2011) Widespread hypomethylation occurs early and synergizes with gene amplification during esophageal carcinogenesis. PLoS Genet 7:e1001356
Zhou, Li; McMahon, Christine; Bhagat, Tushar et al. (2011) Reduced SMAD7 leads to overactivation of TGF-beta signaling in MDS that can be reversed by a specific inhibitor of TGF-beta receptor I kinase. Cancer Res 71:955-63
Kroczynska, Barbara; Joshi, Sonali; Eklund, Elizabeth A et al. (2011) Regulatory effects of ribosomal S6 kinase 1 (RSK1) in IFN? signaling. J Biol Chem 286:1147-56
Schinke, Carolina; Goel, Swati; Bhagat, Tushar D et al. (2010) Design and synthesis of novel derivatives of all-trans retinoic acid demonstrate the combined importance of acid moiety and conjugated double bonds in its binding to PML-RAR-alpha oncogene in acute promyelocytic leukemia. Leuk Lymphoma 51:1108-14
Leshchenko, Violetta V; Kuo, Pei-Yu; Shaknovich, Rita et al. (2010) Genomewide DNA methylation analysis reveals novel targets for drug development in mantle cell lymphoma. Blood 116:1025-34
Schinke, Carolina; Mo, Yongkai; Yu, Yiting et al. (2010) Aberrant DNA methylation in malignant melanoma. Melanoma Res 20:253-65

Showing the most recent 10 out of 23 publications