Grant: 1347-18 | Career Development Program (CDP):
Location:Sloan Kettering Institute for Cancer Research, New York, New York 10087
Project Title: Uncovering The Dysregulated RNA Binding Protein Network In Normal And Malignant HematopoiesisProject Summary:
Although molecular targeted therapy has dramatically changed how we treat cancer, the treatment for acute myeloid leukemia (AML) remains focused on the use of cytotoxic drugs with many patients eventually relapsing with their disease. One of the major drivers of resistance is the persistence of cells that retain the immature properties of stem cells. Cancer cells are made up of proteins expressed by the genes in the nucleus of the cell. Many RNA molecules comprise the information that is the intermediary between genes and proteins. An emerging focus of study is how these RNA molecules may be involved in disease processes. Our laboratory and others have identified that there are specific RNA binding proteins that regulate gene expression programs that are essential for the survival and immature state of acute myeloid leukemia cells. This network of RNA binding proteins is engaged in the most aggressive leukemias and predicts a poor outcome. We developed a screening strategy to identify other RNA binding proteins that contribute to the leukemic state. Using this novel approach, we identified an RNA binding protein called SYNCRIP that we found to be critical for myeloid leukemia and the response of leukemia patients to therapy. Our studies will further explore SYNCRIP’s role in genetic mouse models,human leukemia cell lines, and primary AML patient samples. We plan to understand the mechanism for the regulation of the dysregulated RNA binding protein network in leukemia and to develop therapeutic strategies for treating this aggressive and devastating disease.
Grant: 6551-18 | Translational Research Program (TRP):
Location:The Board of Regents of the University of Wisconsin System, Madison, Wisconsin 53715-1218
Project Title: Matrix Remodeling In The Myeloma Niche: Implications For Minimal Residual Disease And ImmunotherapyProject Summary:
Despite a revolution in the way we treat myeloma in the last 10-15 years, the disease remains incurable for the vast majority of patients. We have devised powerful novel agents and strategies that kill myeloma cells efficiently, yet not at 100%. Some residual cells remain even after the best of treatments and act as the “seed” from which the disease relapses and ultimately claims human lives. In the last 4-5 years, we have become much better at measuring this “minimal residual disease”. Ultimately however, we should not only recognize and size the enemy, we should eliminate it. The burning question therefore becomes: how are these remaining cells protected and shielded from harm? What is the best way to go after them?
We believe that the best strategy against residual myeloma cells is to mobilize the immune system to attack them. This is called “immunotherapy”. Immunotherapy can be a powerful weapon against cancers because it is endowed with inherent specificity and “memory” (in a manner illustrated by how vaccines work): once the immune system recognizes the tumor as foreign and undesirable, it can keep it in check for long time- hopefully, for ever. However, only a small number of patients have so far benefited from cutting-edge immunotherapies that have seen the front page of the New York Times. Part of the reason is that tumors are very capable at putting up bulwarks that fend off the immune system’s “killer” cells. New immunotherapies, such as drugs called “checkpoint inhibitors” work to remove the “brakes” from the immune killer cells. Still, they do not work for all patients.
Our approach is to “breach the bulwarks” that tumors put up to ward off the immune-killer cells. Once the defenses are gone, immunotherapy-mobilized killer cells have a better chance to work. We recently found that a component of the bone marrow environment in which myeloma cells and immune cells interact with each other is a “double-agent”. The “double-agent” is a bone marrow matrix component called versican. In its intact form, versican helps the myeloma tumor cells by neutering the immune system. However, in many cases, a bit from versican’s end (called “versikine”) gets broken off by specialized enzymes, called ADAMTS proteases. Versikine then stimulates the immune system to fight myeloma cancer cells. In other words, versikine (the “daughter” molecule) antagonizes versican (the “mother” molecule). The current proposal aims to investigate the role of versican and versikine in mobilizing the immune system to attack myeloma cells. Tipping the versican-versikine balance may provide powerful marching orders to anti-myeloma immune fighter cells.
Grant: 6528-18 | Translational Research Program (TRP):
Location:Board of Trustees of the Leland Stanford Junior University, San Francisco, California 94144-4253
Project Title: Identifying Relapse Associated Populations At Diagnosis In LeukemiaProject Summary:
Despite high rates of initial response to frontline treatment in many human cancers, mortality largely results from relapse or metastasis. Diverse clinical outcomes occur because all cells within a given tumor do not possess the same behavior or response to therapy. Although there is debate as to whether resistant populations of cancer cells are present at the time of initial diagnosis or whether these traits develop under the pressure of therapy, many studies have suggested that it is the former. Remission, by definition, is the reduction of cancer cells to undetectable levels. Consequently, if cellular populations predictive of relapse exist at diagnosis, it is reasonable to assume that these cells are a minority of the bulk tumor cells. In order to uncover these key populations, it is required to study cancer at the single cell level. Following this reasoning, we propose to perform analysis of primary leukemia cells at diagnosis by examining over 40 proteins on individual cells from patients with B-cell progenitor acute lymphoblastic leukemia (BCP-ALL), the most common leukemia of childhood. The goal of this research is to identify cells associated with relapse at the time of diagnosis. By identifying such populations, we may begin to understand how these cells survive treatment and cause later relapse. In order to organize diverse single-cell data from many primary patient samples, we will use a tool to match each leukemia cell to it's most similar healthy B-cell population. This allows us to compare leukemia cell subsets across patients.
We have optimized this approach in an early study and have identified specific populations of immature B-cells present at diagnosis which are predictive of relapse by applying advanced computational approaches to this single-cell data. This letter of intent outlines a proposal to extend our initial studies using this approach to validate the proposed cellular population which confers relapse risk and to understand how these cells are treatment resistant. To do so, we propose the following efforts:
1. Validate our relapse prediction model in a large cohort of pediatric patient samples and determine if the same cells exist in adult B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) diagnostic samples
2. Determine if primary treatment-resistant cells, taken from patients early in therapy, are similar to the cells we have identified to be predictive of relapse
3. Determine if treatment resistant cells are better suited to grow in commonly used models of BCP-ALL
This proposal presents a novel approach to bring single-cell studies combined with advanced computational approaches to improve outcomes for patients with BCP-ALL.
Grant: 6556-18 | Translational Research Program (TRP):
Location:Dana-Farber Cancer Institute, Boston, Massachusetts 02215
Project Title: Interaction Of RUNX1 And The Cohesin Complex In Megakaryocyte Development And Myeloid DiseaseProject Summary:
Inherited mutations in the RUNX1 gene cause abnormal platelets and a predisposition to the development of acute myeloid leukemia. Similarly, patients with RUNX1 mutations that are acquired during adult life have an analogous platelet abnormality and predisposition to acute myeloid leukemia. In order for patients with RUNX1 mutations to progress to acute leukemia, additional mutations need to be acquired. We have found that mutations in the STAG2 gene can cooperate with RUNX1 mutations, likely leading both to the development of worsening platelet abnormalities and progression to overt malignancy.
Our goals are to answer two questions: (1) Does loss of RUNX1 and STAG2 lead to abnormal platelet precursor cell formation, with resultant platelet dysfunction and increased risk of bleeding? If so, we would like to pro-actively identify these patients so that appropriate measures can be taken to mitigate their risk of bleeding, particularly when undergoing diagnostic procedures. (2) Can we model abnormal platelet precursor cell function and AML disease progression in human and mouse bone marrow stem and progenitor cells? If so, this would provide functional evidence that loss of normal function of STAG2 and RUNX1 leads to abnormal platelet precursor cell formation and/or development of leukemia. In addition, these models would facilitate studies of novel therapeutic agents, which are desperately needed for this patient population.
Treatment options for patients with RUNX1 mutations are limited, and better understanding of the mechanisms by which leukemia causing genes contribute to leukemia development in patients will inform the design of urgently needed new treatments. We propose to develop models and investigate therapeutic approaches that have the potential to benefit individuals with RUNX1 mutations.
Grant: R0859-18 | Quest for CURES (QFC):
Location:Joan & Sanford I. Weill Medical College of Cornell University, New York, New York 10022
Project Title: Targeting Of The Senescent Vascular Niche To Treat Age-related Hematopoietic Malignancies.Project Summary:
Physiological aging directly leads to a multitude of age-related diseases, including cardiovascular disease, arthritis and cancer, that affect nearly all systems of the body. The goal of this proposal is to identify alterations in the aged bone marrow vascular system that initiate and facilitate the progression of hematopoietic malignancies. We have demonstrated that vascular cells are a critical component of the bone marrow microenvironment and support the overall health and fitness of blood stem cells. Preliminary data generated in our laboratory demonstrated that the vascular system is altered during the aging process, resulting in the premature aging and a decrease in functionality of the blood stem cells. In order to address whether the aging process promotes hematopoietic malignancies by dysregulating the bone marrow vascular system, we have developed a means to isolate and transplant bone marrow vascular cells to aid in the rejuvenation of the aged bone marrow microenvironment. Utilizing our protocols, we will be able to screen for altered factors produced by aged vascular cells that promote the aggressiveness and elusiveness of leukemic cells. Overall, our laboratory is aiming to design novel therapeutic strategies to be used as an effective means to reduce the morbidity and mortality associated with chemotherapy and radiological regimens used to treat a wide range of aged-related malignancies.
Grant: 5472-18 | Career Development Program (CDP):
Location:British Columbia Cancer Agency Branch, Vancouver, British Columbia V5Z 1L3
Project Title: Roles Of MicroRNA MiR-146a In Hematopoietic Stem Cell FunctionProject Summary:
Myelodysplastic syndrome (MDS) is a cancer of blood stem cells, the blood-forming cells in the bone marrow. In MDS, cancerous blood stem cells lose the ability to make blood cells, and can also block the function of the remaining normal blood cells. Aging and environmental factors are associated with developing MDS, but how these processes affect the function of both cancerous and coexisting normal blood stem cells in MDS remains poorly understood. Few treatments are available for MDS, and treatment resistance develops in most patients; therefore, understanding the molecular mechanisms that disrupt blood stem cell function in MDS is critical for improving patient outcomes.
I aim to study the molecular mechanisms affecting the function of coexisting cancerous and normal blood stem cells in a mouse model of MDS. I will focus in particular on a subtype of MDS that lacks the gene miR-146a, as we have found that miR-146a deletion in a mouse model causes aggressive MDS symptoms with severe defects in blood stem cell function. To better recreate the bone marrow of MDS patients in which normal and mutant cells coexist, I will co-transplant equal amounts of normal bone marrow with miR-146a-deleted bone marrow, and study the function of both cancerous (miR-146a deleted) and normal (miR-146a intact) blood stem cells. Our data suggest that miR-146a deletion activates inflammation, increases cellular aging, and disrupts energy metabolism in blood stem cells. I will use chemical and genetic strategies to manipulate inflammation, aging pathways, and energy metabolism, with the hope of reversing the dysfunctions of cancerous and normal blood stem cells in this mouse model.
This research will provide the first evidence as to whether drugs targeting inflammation, aging pathways, or energy metabolism may be useful additions to current treatment regimens for MDS. As few effective long-term treatments are available for MDS, my research may one day improve the prognosis for patients with MDS.
Grant: 2317-18 | Career Development Program (CDP):
Location:Washington University in St. Louis, St. Louis , Missouri 63130
Project Title: Targeting Leukemia Stromal Interactions In T-ALLProject Summary:
T-cell acute lymphoblastic leukemia (T-ALL) is a subtype which comprises about 20% of all cases of acute lymphoblastic leukemia. T-ALL is a particularly rare disease in adults, with only about 600 new cases per year in the United States. Furthermore, the prognosis of adults is poor; only 40% of adults with T-ALL are cured with current treatments.
Our laboratory work has demonstrated that T-ALL cells interact with normal cells present in their local environment (called the “microenvironment”), which provides key signals that regulate tumor growth and survival. Our research has focused on a specific protein, CXCR4, which is present in T-ALL cells. In T-ALL, the tumor microenvironment provides a potent growth and survival signal, which is mediated by CXCR4, to T-ALL.
We hypothesize that it is possible to disrupt this tumor-microenvironmental interaction as a means to treat T-ALL patients. We will disrupt the key survival signal to T-ALL cells using a novel inhibitor of CXCR4 known as BL-8040. We are currently conducting a multicenter study to combine BL-8040 treatment with chemotherapy in patients with T-ALL that has relapsed or is refractory to standard treatments. As part of this study, we will test blood and bone marrow samples from patients after treatment to determine the effects of BL-8040 on leukemia cells. We will also conduct additional preclinical studies to test the effects of new combinations of drugs to improve the effectiveness of BL-8040. The overall goal of this project is to target tumor-microenvironment interactions to improve the outcomes of patients with T-ALL.
Grant: 5464-18 | Career Development Program (CDP):
Location:Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037
Project Title: The Impact Of Immunoglobulin Isotype (IgM Vs IgG) On B Cell Lymphomagenesis And Progression.Project Summary:
B-cell lymphomas continuously multiply because growth regulation signaling is altered to stay ‘on’ all the time. This signaling is normally triggered by activation of proteins called receptors on the cell surface. Most lymphomas require signaling from a group of receptors called the B-cell receptor (BCR). Normal B-cells produce a type of BCR, called immunoglobulin (Ig), in a process called the germinal center (GC) reaction. There are several types of Ig subtypes – IgM, IgG, and IgA isotypes—which are produced during the GC in response to stimuli generated by agents foreign to the body. B-cells with different Ig isotypes behave and function differently. Diffuse large B-cell Lymphoma (DLBCL) frequently arises during the GC reaction and express either IgM, IgG or IgA types of BCR. However, the signaling potential and role of Ig isotypes in B-cell lymphoma is poorly understood.
DLBCL can be further sub-categorized into two subgroups: the Germinal Center B-cell type (GCB) DLBCL and Activated B-cell type (ABC) DLBCL. While ABC-DLBCL is a more aggressive disease with a poorer clinical outcome, the GCB-DLBCL is a less aggressive disease with better patient outcomes. Importantly, both subgroups of DLBCL depend on B-cell receptor (BCR) signaling for their survival and proliferation. Interestingly, GCB-DLBCL cells primarily express the IgG isotype of BCR, whereas the majority of ABC-DLBCL cells express IgM. Consistent with these findings, the two subgroups of DLBCL respond differently to BCR signaling inhibition by ibrutinib. In a recent study, there was only a 5% response rate among GCB-DLBCL patients treated with ibrutinib, whereas there was a 38% response rate among ABC-DLBCL patients. These findings, along with the expression of different Ig isotypes, are suggestive of the involvement of differential BCR signaling cascades in the pathogenesis of GCB- versus ABC-DLBCL. To address this idea, we analyzed changes in protein activation between IgM and IgG positive cells in normal B-cells from mice. Remarkably, we observed differential activation of common signaling components among the different Ig isotypes. We are currently seeking to elucidate the molecular mechanisms by which different Ig isotypes impact the survival and proliferation of lymphoma cells. We will also study the effect that these differences may have on regulating the sensitivity of lymphoma cells to approved therapies. Lastly, during these studies we hope to uncover novel therapeutic targets, which may eventually lead to better treatments for DLBCL.
Grant: 1352-18 | Career Development Program (CDP):
Location:New York University School of Medicine, Boston, Massachusetts 02241-415026
Project Title: MicroRNA Regulation Of Leukemia Stem CellsProject Summary:
Acute myeloid leukemia (AML) is composed of two populations of cells with differing characteristics. The bulk population directly gives rise to the disease symptoms. The second population is very small and is composed of leukemia stem cells (LSCs), whose role is to initiate disease and generate the AML bulk population. These self-renewing LSCs are therapy resistant and mediate disease relapse; therefore, it is critical to understand the mechanisms that regulate LSCs in order to develop strategies designed with the intent to cure.
The characteristics of all cells are determined by DNA contained in the nucleus of the cell. The information DNA provides is converted to RNA, which is exported out of the nucleus into the cytoplasm of the cell, where the cell’s proteins are produced. Small RNA molecules, called microRNAs (miRNAs) regulate the expression of protein-encoding genes in cells.
My laboratory has shown that miRNAs can regulate normal blood stem cell function, promote the development of AML, and regulate LSCs. We have shown that two nearly identical microRNAs are frequently overexpressed in LSCs, but it is unclear what their relative contributions are to regulating leukemia cell survival and LSC function. We hypothesize that these two microRNAs can serve overlapping but non-redundant functions due to differences in their location within the cell. Indeed, while most miRNAs are thought to function in the cytoplasm of the cell, some microRNAs enter the nucleus, and we predict that such a nuclear distribution will affect their ability to regulate genes critical for LSC function. Leveraging our expertise in LSC biology, as well as novel technologies that we have either developed or optimized, we seek to better understand the role of these critical miRNAs in AML disease initiation and maintenance. Thus, we propose to: 1) Determine whether structurally similar microRNAs play similar or unique roles in LSCs; 2) Determine whether the subcellular location of microRNAs dictates their ability to regulate LSC function; and 3) Identify the genes that these microRNAs regulate, specifically in LSCs. Overall, we expect to not only reveal how microRNAs regulate LSCs but also to provide general insights into how microRNAs can differentially regulate gene expression based on their position within a cell. These investigations may lead to a better understanding of AML and may provide avenues for novel therapeutic approaches.
Grant: 6543-18 | Translational Research Program (TRP):
Location:Children's Research Institute, Washington, District of Columbia 20010
Project Title: Novel Combination Immunotherapies For High Risk Hodgkin's LymphomaProject Summary:
Hodgkin’s lymphoma (HL), a type of blood cancer is largely curable but with significant long-term side effects. Moreover 10-20% of patients are resistant to treatment and difficult to cure. HL is unique that the tumor cells are surrounded by an inhibitory environment that makes the immune system dysfunctional and allows evasion from an effective anti-tumor response. Understanding this environment may provide insight into how we can spur the immune system to attack HL cells effectively. Like many cancer cells, HL cells escape the immune attack by expressing a protein called PD1 or PDL-1, which is is normally expressed by healthy T cells to prevent them from attacking healthy cells. PD1-inhbitors are drugs that can bind to the PD-1/PDL-1 on lymphoma cells thereby releasing the “brakes” on the immune system to mount a strong attack on the HL cells. The lymphoma cells also secrete certain chemicals like TGFβ which incapacitates the immune cells to kill the lymphoma cells effectively. The goal of this project is to understand how we can change the tumor microenvironment sufficiently to unleash pre-existing anti-tumor immune responses and allow more successful incorporation of killer- T cells. We will determine if PD1 inhibitors when given in combination with the administration of a novel cancer killing T-cell therapy will produce long-lasting cures in patients with high risk HL with less side effects than conventional chemotherapy. Finally, we will continue to improve the efficacy of our combination immunotherapy approach by also engineering the cancer killing T cells to become resistant to the inhibitory chemical TGFβ which is released by the HL tumor cells and has devastating effects on T cell function in vivo. In the laboratory we will determine if these engineered T cells have enhanced killing ability compared to the non engineered T cells.