Myelodysplastic Syndromes: Hematopathology. Analysis of SHIP1 as a potential biomarker of Disease Progression

Transcription

1 Myelodysplastic Syndromes: Hematopathology. Analysis of SHIP1 as a potential biomarker of Disease Progression Carlos E. Bueso-Ramos, M.D., Ph.D Department of Hematopathology The University of Texas M. D. Anderson Cancer Center Houston, Texas.

2 Myelodysplastic Syndromes (MDS) Clonal disorder of marrow stem/progenitor cells Cellular bone marrow with dysplastic, ineffective hematopoiesis Myeloblasts <20% Heterogeneous group of disorders Increased risk of blastic transformation Occurs mainly in older patients

3 WHO 2008 Classification of MDS Refractory cytopenia with unilineage dysplasia (RCUD) Refractory anemia (RA) Refractory neutropenia (RN) Refractory thrombocytopenia (RT) Refractory anemia with ring sideroblasts (RARS) Refractory cytopenia with multilineage dysplasia (RCMD) Refractory anemia with excess blasts (RAEB-1, -2) Myelodysplastic syndrome with isolated del(5q) Myelodysplastic syndrome, unclassifiable (MDS,U) Childhood myelodysplastic syndrome Refractory cytopenia of childhood (RCC)

4 2008 WHO Classification of AML AML with recurrent genetic abnormalities AML with myelodysplasia-related changes Therapy-related myeloid neoplasms t-aml (blasts 20%+) t-mds (blasts <20%) (ASH 2009, Kim et al, 3796) t-mds/mpn or t-aml (based on # blasts present) Do NOT include transformation of MPN

5 Approach to the Classification of MDS Isolated del(5q) dysplasia, cytopenia unilineage dysplasia Uni/bicytonenia RCUD RA, RARS RN RT < and no AR Multilineage dysplasia cytopenia (uni/bi/pan) RCMD Blast % (<20%) 1 % in PB or 5 % in BM Auer rods (AR) Monocyte < 1,000 = 1% in PB MDS-U > or AR RAEB-1 unilineage dysplasia, pancytopenia dysplasia < 10% with abnormal CG* Immunophenotype RAEB 5% in PB or 9% in BM < > R/o Hypoplastic AML R/o MDS/MPN MPO, butyrate RAEB-2

6 MDS and other Hematologic Disorders AML with t(8;21) with less than 20% blasts AML FAB M6 when erythroblasts are > 50% MDS with PNH features PNH AA MDS MPD AML MDS with hypocellular marrow (ASH Blood 2009, Tong et al, Abstract #3819) MDS with fibrosis MDS with thrombocytosis

7 MDS Clonal Dynamics

8 MDS 3 months later AML

9 MDS Disease Progression Pre-diagnosis Phenotypic diversity Advanced disease The clone and its microenvironment Latency period Ineffective hematopoiesis Normal hematopoiesis barrier Cytopenias Transformation to AML or ALL Genetic hits * Some consequences: Stem cell damage * Immune response to altered stem cells Microenvironment (bone marrow) abnormalities Proapoptotic Cytokines elevated ++ Proliferation barrier More malignant clones break trough and proliferate + Second hit Or less favorable microenvironment Increase in number of blasts Bone Marrow failure Progressive cytopenias *Common chromosomal abnormalities include: del 5q, +8, -sex (X or Y), 17p-, -7/del 7q, and 20q-. + Increase in marrow blast percentage. Normal cell development crowded out. Increased VEGF levels, which support clonal proliferation. ++ TNF-α (tumor necrosis factor- α ), TRAIL, FasL, IL-1β TGF-β 1(transforming growth factor-b1).

10 Multiple Clones &Microenvironments Bottlenecks / Selective Pressure Stem/progenitor cells N N N N N MUTATIONS

11 Molecular Basis of this Transformation remains unknown Abnormal Signaling Pathways Loss of p53 Function Epigenetic Silencing of Genes

12 Activation of PI3K/AKT/NF-kB underlies this transformation SHIP-1 Akt/PI3K Expert Opin.Biol.Ther.,2007,7

13 NF-kB Expression in CD34+ Blasts of RAEB-2 Nuclear p65 Nuclear p50 Cytoplasmic p52 Bueso-Ramos, et al. Human Pathol, 2004

14 Frequent elevation of p-akt Ser473 in BM cells from high-risk MDS patient See also: Nyakern, M, et al. Leukemia 20: , 2006

15 SHIP1 Protein SHIP1 is expressed specifically in hematopoietic cells In the mouse knockout, SHIP1 behaves as a myeloid tumor suppressor (Blood 2004;103:4503) Dominant-negative mutations of SHIP gene have been detected in rare (1/192) patients with AML Leukemia Lymph 2006;103:4503

16 Normal Bone Marrow Biopsy Biopsy Cytospin Normal CD34+ Selected Blasts 60% SHIP-1 positive

17 Down-regulation of SHIP1 protein in late-stage MDS

18 nriched CD34+ blasts of SHIP1 protein: Clonal Dynamics of Downregulation RAEB-1 RAEB-2 11% SHIP-1 positive AML cell line

19 SHIP1 Expression in MDS in the context of BM Microenvironment

20 Reduction in SHIP1: Protein levels may be due to translational repression by mirna Transcripts for SHIP1 only slightly decreased in CD34+ cells from MDS.

21 micrornas Short (19 to 25 nt) single-stranded RNA molecules Regulate target genes by repressing translation or inducing mrna degradation Critical in regulation of cell cycle, apoptosis and differentiation Function as oncogenes and tumor suppressor genes Play important roles in the development of cancer

22 Significantly Higher Expression of MiRNA-155 in CD34+ Blasts in late stage MDS by qpcr 3.00 relative expression normal 1 normal 2 normal 3 mds 1 mds 2 mds 3 sample

23 Inositol phosphatase SHIP1 is a primary target of mir-155 Ryan M. O Connell a,1, Aadel A. Chaudhuri a,1, Dinesh S. Rao a,b,1, and David Baltimore a,2 a Division of Biology, California Institute of Technology, 330 Braun, 1200 East California Boulevard, Pasadena, CA 91125; and b Department of Pathology and Laboratory Medicine, The David Geffen School of Medicine, University of California at Los Angeles, Le Conte Avenue, Los Angeles, CA Lee, et al. ASH Blood 2009, Abstract 3824: SHIP1 is a navel tumor suppressor in MDS and it is silenced by mir-210 and mir-155 O Connell, R.M., et al. PNAS 106: , 2009

24 SHIP1 is a Novel Tumor Suppressor for Late-Stage MDS and It is Silenced by 1 mir First hit/class II mutation: TET2, RUNX1 and RSP14 -Differentiation Silencing of SHIP1 by mir-155 and mir-210 Second hit/class I mutation: FLT3, RAS, KIT, NPM1 -Proliferation/survival AML birth Normal stem cell Early-stage MDS Advance-stage MDS 60 yrs

25 Aberrant Activation of the PI3K/AKT pathway underlies this Transformation SHIP-1 mir

26 Conclusions MiRNA-155 has been shown to repress SHIP1 protein levels expression. SHIP1 could serve as clinical biomarker for tumor progression. Why AML with high SHIP1+ are not sufficient to control constitutive activation of PI3K/AKT? * Mutation in catalytic domain * Mutation in interacting domains may interfere with recruitment of SHIP1 to the cytoplasmic membrane

27 Conclusions Development of MDS involves multiple genetic lesions that compliment each other Aberrant signal transduction enhances the survival and proliferation of LSC. Critical functional dependencies of LSC result in activation of limited effector pathways RAF/MEK/ERK, PI3K/AKT

28 Thank you Thank You!