microRNA and immunophenotypic alterations in hematologic malignancies

Clinical Center

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Abstract

1. MicroRNA and gene expression profiling of follicular lymphoma (FL): The first phase of this project was completed and published in Haematologica (#1 in Bibliography) earlier this year. microRNA profiles of sorted FL tumor cells from 19 follicular lymphoma samples and 5 control samples were assayed for the expression of 851 human microRNAs. In order to correlate microRNA expression with expression of potential mRNA targets of genes known to play a role in B-cell development and lymphomagenesis, we performed focused gene expression profiling (200 human genes) in parallel using the nCounter NanoString platform. We identified a unique microRNA signature comprised of 44 miRs that distinguished FL tumor cells from normal germinal center B-cells. Expression patterns of subset of 23 miRs were associated with improved response to chemotherapy. Functional studies demonstrated that miR-20a/b targets CDKN1A/p21 and miR-194 targets SOC2 in FL potentially contributing to tumor cell proliferation and survival. 2. Cytokine and microRNA profiling of serum and bone marrow supernatant of multiple myeloma (MM): Previously we performed cytokine profiling (IL-1beta, IL-2, IL-4. IL-5. IL-6. IL-8. IL-10. IL-12 p70, IL-13. IFN-gamma, and TNF-alpha) in serum and bone marrow supernatant samples of 16 MM and 8 controls and identified 3 cytokines that are overly expressed in MM in comparison to controls. Concurrent array based miR profiling in bone marrow supernatant of MM identified a panel of significantly differentially expressed miRs which formed a unique signature of the BM microenvironment in MM. Some of these miRs are putatively involved in regulation of cytokine signaling pathways and cell proliferation. A subset of 18 of the significant miRs were subsequently assayed in serum from the same patients by qPCR to identify miRs that may be shed into the circulation and serve as diagnostic biomarkers or markers of disease progression. During 2012 we expanded the study to include serum samples from myeloma precursor disease (MGUS and SMM) to determine which aberrant miRs were aberrantly expressed in MGUS, and which miRs were associated with disease progression. A subset of the myeloma significant miRs showed aberrant expression in the precursor disease state (MGUS), while another subset were not aberrantly expressed in MGUS, and may represent biomarkers for disease progression. A manuscript is in preparation. 3. MicroRNA profiling of GATA2 mutation related MonoMAC and MDS/AML: We generated microRNA array based profiles of patient derived MonoMAC GATA2 mutated cell lines, followed by functional studies to identify mRNA targets of the candidate miRs, which could potentially cooperate with GATA2 deficiency in generating cytopenias and MDS/AML. Three aberrant microRNAs were validated by qPCR and putative mRNA targets that regulate apoptosis were confirmed in functional studies in cell lines. We are engaged in further studies to elucidate the potential mechanisms of apoptosis, progressive cytopenias and bone marrow failure related to inherited GATA2 mutations and the aberrant miRs we identified. Additionally, a collaborative manuscript on GATA2 mutation related immunodeficiency and hematopoiesis was published with Steve Holland and Emery Bresnick in JCI (#2 in Bibiography). Additional collaborative manuscripts were published in 2012: a) Hematopoietic response in aplastic anemia to treatment with Eltrombopag (collaboration with Cynthia Dunbar, NHLBI; #3 in Bibliography); b) Expression of annexinA1 in cases of Hairy cell leukemia and Hairy cell leukemia variant that were evaluated for the BRAF V600E mutation (collaboration with Robert Kreitman, NCI; #4 in Bibliography) c) Diagnostic features of MDS post allogeneic transplant (collaboration with Alan Wayne, NCI; #5 in Bibliography).