Grant: 6485-16 | Translational Research Program (TRP):
Location:Regents of the University of Michigan, Pittsburgh, Pennsylvania 15251-2131
Project Title: Therapeutic Targeting Of Ash1L Histone Methyltransferase In Acute LeukemiasProject Summary:
Acute Myeloid Leukemia (AML) is a highly incurable disease and there is an urgent need for development of novel therapies. AML patients with high expression level of HOX genes have particularly unfavorable prognosis. Likewise, high level of HOXA9 was also shown to be implicated in T-cell acute lymphoblastic leukemia (ALL) cases. Therefore, regulation of HOX genes expression, in particular HOXA cluster genes, should represent an attractive target for drug discovery. Small molecule inhibitors that reduce HOXA gene expression might represent a potential treatment strategy for acute leukemia patients. Ash1L (Absent, small or homeotic 1-like) is a histone methyltransferase that belongs to a Trithorax group proteins involved in regulation of HOX genes. We have recently discovered that silencing of Ash1L expression results in a strong downregulation of HoxA genes in vivo.
In this project, we propose to target histone methyltransferase activity of Ash1L with small molecules as a potential therapeutic strategy for acute leukemias with high expression level of HOXA genes. We have already developed small molecule inhibitors of the Ash1L histone-methyltransferase activity, which directly bind to the SET domain of Ash1L and inhibit its enzymatic activity. These molecules represent very attractive lead compounds for further drug discovery efforts to develop potent Ash1L inhibitors with favorable drug-like properties. To achieve this goal, we propose three specific aims. Aim 1 will be focused on medicinal chemistry efforts combined with structural biology to improve potency and drug-like properties of our lead compounds, with the overall goal to develop Ash1L inhibitors suitable for in vivo efficacy studies in animal models of acute leukemias. In Aim 2 we will perform extensive characterization of Ash1L inhibitors in a panel of acute leukemia cells with various levels of HOXA9 and MEIS1 expression to assess their cellular effect and specificity. In addition, the most potent compounds will be evaluated in vivo in mice models of acute leukemias. In Aim 3 we will put efforts to assess whether small molecule inhibition of Ash1L affects the self-renewal potential of leukemic stem cells. We expect these studies will result in development of promising candidate compounds as novel therapeutic agents for acute leukemias with high expression level of HOX genes.
Grant: 1329-16 | Career Development Program (CDP):
Location:The Trustees of Columbia University in the City of New York, Columbia University Medical Center, New York, New York 10027
Project Title: Transcriptional Regulation Of Non-coding RNA Promotes AID Targeting And Chromosomal Alterations In The B Cell GenomeProject Summary:
B-lymphocytes are known for their ability to generate antibodies of the highest affinity to neutralize various antigens we encounter. In the process of generating high-affinity antibodies, B cells mutate the immunoglobulin loci (antibody encoding genes) and other regions of the B cell genome. These mutations are catalyzed by the enzyme activation induced deaminase (AID). Sometimes AID, in its effort to generate genetic diversity, mutagenizes other (inappropriate) regions of the B cell genome which eventually act as genetic lesions responsible for chromosomal translocations, causing cancer. Recent advances in biology have lead to the paradigm-shifting discovery that close to 90% of mammalian genomes express non-protein coding (nc) RNAs that may have some unidentified biological function. We aim to investigate how AID utilizes the non-coding RNA transcriptome of B cells to identify and mutate its target DNA sequences. We have identified a subset of large non-coding RNAs (lncRNAs) that are expressed from AID target DNA sequences in B cells; some of these lncRNAs have homologs in mammalian cells and that are mutated in B cell lymphomas. Using mouse genetics, genomics, and biochemistry we aim to investigate the role of these novel lncRNAs in B cell development and tumorigenesis. We realize that the expression of some of the identified ncRNAs may directly correlate with oncogenesis; we plan to evaluate the potential of these RNAs as cancer biomarkers.
Grant: 5447-16 | Career Development Program (CDP):
Location:Board of Trustees of the Leland Stanford Junior University, San Francisco, California 94144-4253
Project Title: SINGLE CELL RNA IMAGE SEQUENCING FOR SPATIO-TEMPORAL ANALYSIS OF T-CELL DEVELOPMENT FROM STEM CELLSProject Summary:
Grant: R6503-16 | Translational Research Program (TRP):
Location:Regents of the University of Michigan, Pittsburgh, Pennsylvania 15251-2131
Project Title: Peripheral T-cell Lymphoma, Not Otherwise Specified: The Cell Of Origin As A Predictive Biomarker And Therapeutic Target.Project Summary:
T-cell cancers, collectively referred to as T-cell lymphomas (TCLs), are relatively rare, difficult to classify, and poorly understood. Most TCLs are clinically aggressive and resistant to standard chemotherapy regimens. Therefore, these lymphomas are rarely curable with existing therapies. We believe that the biology of normal (noncancerous) human T cells can provide clues about TCL classification that may lead to the development of improved treatment strategies. For example, different subsets of normal T cells are tightly controlled by a group of regulatory proteins. One of these proteins, called GATA-3, regulates the growth and survival of a particular T-cell subset. We speculated that expression of GATA-3 and other related proteins might determine important aspects of TCL biology and aid in TCL classification. We found that the majority of patients with the most common TCL express either GATA-3 or an alternative regulatory protein, T-bet. These patients were previously thought to have the same TCL. However, our findings demonstrate that this TCL comprises two clinically and molecularly distinct subsets: one characterized by GATA-3 expression and the other by T-bet expression. These findings have significant implications for the classification of this TCL and for its treatment. For example, one of these TCL subsets may respond better than the other to standard chemotherapeutic agents. We will conduct a multicenter clinical trial to address this possibility. Patients with relapsed or refractory TCL will be classified as having either “GATA-3” or “T-bet” TCL prior to treatment with one of four standard chemotherapy agents (selected by their physician), and the response to treatment will be subsequently evaluated. We anticipate that the results of this study will help physicians select the “right therapy” for the “right patient”. Part of this effort will require development of reliable, accurate, and clinically accessible assays to identify these TCL subsets. We will examine two complementary assays in a large cohort of well-characterized TCL patients. While optimization of currently available therapies is important, an equally important goal is the development of improved therapeutic strategies. For the second proposed study, we will test a new therapeutic strategy based on our work demonstrating that GATA-3 confers resistance to chemotherapy. Since GATA-3 expression is controlled by a cell surface protein called the T-cell receptor (TCR), inhibition of TCR signals by the oral chemotherapeutic agent Ixazomib should inhibit GATA-3 expression in TCL. This novel therapeutic strategy will be examined in a single center, phase II study. We hope that the knowledge gained from this body of work will ultimately improve outcomes for patients afflicted with these aggressive lymphomas.
Grant: 6488-16 | Translational Research Program (TRP):
Location:Albert Einstein College of Medicine, Inc., Bronx, New York 10461
Project Title: STAT3 Inhibition As A Therapeutic Strategy Against MDS And AML Stem CellsProject Summary:
Myelodysplastic syndromes and acute myeloid leukemia are blood cancers that are increasing in incidence and can result from exposure to harmful chemicals and ionizing radiation. These diseases are caused by genetic changes in the blood stem cells that lead to a disruption of their functionality. Blood stem cells are capable of differentiating in all different types of blood cells and rely on certain networks of genes that have to be switched on or off in a coordinated manner. We have shown that stem cells in MDS and AML patients have genetic alterations. We have also shown that these abnormal stem cells are not killed by drugs such as azacytidine and are a cause of disease relapse. Thus, identification of targets against these abnormal stem cells is important in the development of future curative therapeutic strategies. In this proposal we aim to target MDS stem cells with a drugs against the protein STAT3. We have shown that abnormal stem cells from MDS and AML patients have higher levels of STAT3 and that patients with higher STAT3 levels have a shorter lifespan. Our work has shown that inhibiting this protein can lead to death of MDS/AML stem cells and potentially prevent disease relapses. We propose to test a novel protein based drug called STAT3-ISIS-Rx in human samples and animal models of MDS and AML. This agent is also a selective inhibitor of the STAT3 protein and is being tested in clinical trials in lymphoma We also propose to test an approved drug, Pyrimethamine, that is being used in another leukemia (CLL) based on its ability to inhibit the STAT3 protein. We will test whether inhibition of STAT3 by these drugs can inhibit genetically abnormal MDS stem cells in patients. Our studies will lead to its development of these agents in future clinical trials in MDS and AML patients.
Grant: R6501-16 | Translational Research Program (TRP):
Location:Mayo Clinic Rochester, Minneapolis, Minnesota 55486-0334
Project Title: Overcoming T-cell Exhaustion In Follicular B-cell LymphomaProject Summary:
Immune cells within the tumor play a critical role in follicular non-Hodgkin lymphoma (NHL). Although lymphoma B-cells predominate, other cells are commonly present in malignant lymph nodes. These cells include T lymphocytes that appear to target lymphoma B-cells, and while increased numbers of intratumoral T-cells are associated with an improved outcome, intratumoral T-cells seem unable to eradicate the malignant cells.
In work done during the initial funding period, we have shown that intratumoral T-cells in follicular lymphoma are functionally exhausted due to chronic cytokine stimulation. Specifically, we have found that immunostimulatory proteins including interleukin-12 (IL-12), transforming growth factor beta (TGF-β) and monokine induced by gamma interferon (MIG/CXCL9) cause T-cell exhaustion. Exhausted T-cells are characterized by expression of TIM-3 and PD-1 on the cell surface. Exhausted cells are unable to grow, produce cytokines or respond to activation, and signaling through PD-1 perpetuates the exhausted T-cell phenotype. Increased numbers of intratumoral TIM-3+PD-1+ T-cells are associated with a poor prognosis and an increased likelihood of transformation to a more aggressive lymphoma.
We therefore hypothesize that blocking PD-1 signaling will reverse T-cell exhaustion and result in clinical benefit for lymphoma patients. Initial clinical trials have reported responses in low-grade lymphoma patients treated with anti-PD-1 antibodies, but not all patients treated benefited from this therapy. In this grant renewal, we propose to test the safety and efficacy of an anti-PD-1 antibody, pembrolizumab, in patients with relapsed low-grade lymphoma and to identify the immune cell composition that is associated with clinical responses. We will then determine whether reversal of T-cell exhaustion is the dominant mechanism responsible for clinical benefit.
Successful completion of the aims of this proposal will result not only in confirmation of a novel therapy to improve tumor immunity in patients with follicular lymphoma, but also in the identification of an immune signature that identifies patients most likely to benefit from this treatment approach.
Grant: 1331-16 | Career Development Program (CDP):
Location:Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104-6205
Project Title: Towards A Quantitative Understanding Of Mixed-lineage Leukemia Family Substrate TargetsProject Summary:
Mixed-lineage leukemia (MLL) gene mutations are frequent in both pediatric and adult leukemias. While studies have helped define the genetic determinants driving these leukemias, these aggressive blood cancers still have the worse prognosis despite improved treatment options. Therefore, the development of novel drug therapies is highly needed. However, before new therapeutic strategies can be designed, a thorough understanding of the molecular level consequences of MLL gene targets must be achieved. The MLL gene encodes for an enzyme that adds a chemical modification (methyl) to the side chains of lysine amino acids, with its most well-known target being histone H3, a protein that is involved in structurally making our chromosomes and controlling gene expression. Nevertheless, as there are several related MLL gene family members and their enzymatic activities are significantly altered in the disease state, determining how these enzymes impact cellular targets will greatly help in understanding the molecular pathology of this disease. Towards this end, my lab has been developing novel technology that we propose to use to identify and study downstream targets of MLLs that could be critical for leukemia induction and propagation. We believe that our approaches will help improve the fundamental understanding of the molecular level causes of MLL triggered leukemia and could lay down the foundation for new diagnostics or development of innovative therapeutic intervention.