Grant: 5460-18 | Career Development Program (CDP):
Location:Sloan Kettering Institute for Cancer Research, New York, New York 10087
Project Title: Defining The Molecular Determinants Of Cysteine Acquisition And Redox Homeostasis In B Cell LymphomaProject Summary:
A key feature of blood cancer cells is the adaptation of their internal cellular metabolism to support nutrient utilization for continuous cell proliferation. Excessive nutrient consumption results in increased levels of reactive oxygen species (ROS). Since increased ROS levels are toxic, there must be countermeasures in place in order for the tumor cell to survive. It is therefore critical for these cancer cells to increase antioxidant capacity in order to overcome the oxidative stress caused by ROS during cancer progression. My research is designed to provide novel insights into the metabolic basis of how cancer cells regulate oxidative stress to maintain an appropriate equilibrium for their own survival. This process of maintaining equilibrium is called “redox homeostasis.”
My preliminary results suggest that two mechanisms function to maintain redox balance in cancer cells and that most cancer cells are committed to one or the other mechanism. It is thought that many blood cancer cells preferentially depend only on the mechanism that creates the amino acid cysteine by modifying another amino acid, which then is converted into the ROS scavenger glutathione. My research will employ metabolic analysis and biochemical approaches to investigate the molecular basis of redox controls and apply various cellular assays to evaluate the functional significance of these controls. My research may reveal critical knowledge of how blood cancer cells maintain redox homeostasis and may also contribute to advances in the clinical treatment of these cancers. Pharmacological inhibitors are currently available to target the metabolic pathway that supports redox balance in blood cancer cells. These chemicals may be adapted and tested for clinical use. Furthermore, the proposed mechanism reveals the metabolic vulnerability of these cancer cells. Therefore, a specific diet may be applied clinically, alone or in combination with standard chemotherapeutics, which may lead to better outcomes for some blood cancer patients.
Grant: 1350-18 | Career Development Program (CDP):
Location:Brigham and Women’s Hospital, Boston, Massachusetts 02241-3149
Project Title: Enhancing The Clonal Selectivity Of Current Drug Therapies In Myeloproliferative NeoplasmsProject Summary:
The objective of my proposal is to develop better treatments for patients with a group of blood cancers called myeloproliferative neoplasms (MPN). There are currently no curative treatment options for MPN apart from stem cell transplantation, which is a high-risk and sometimes life-threatening procedure.
None of the currently available drug treatments for MPN can cure the disease. They can only improve the symptoms. In 2011, the Food and Drug Administration approved a new type of drug treatment for MPN, called JAK2 inhibitors. With the approval of JAK2 inhibitors, MPN patients and their doctors had high hopes that these drugs would have the ability to change the course of MPN, rather than just control symptoms. Unfortunately, JAK2 inhibitors have disappointed in this regard, and although useful at controlling MPN-related symptoms, they cannot eradicate the disease or prevent it from turning into leukemia. In view of this, we are asking the following questions: (1) Why are JAK2 inhibitors not as effective in the treatment of MPN as was initially hoped? (2) What are the mechanisms by which MPN patients are resistant to JAK2 inhibitors? (3) What novel drug targets, if also inhibited, could make JAK2 inhibitors more effective?
We propose to identify (i) the genes that confer resistance to JAK2 inhibitors and (ii) the genes that when inhibited increase the efficacy of JAK2 inhibitors. We plan to do this using a new technology called CRISPR gene editing. With this powerful technique we can target every gene in the human genome in a completely unbiased fashion to identify the genes that underlie JAK2 inhibitor treatment failure. The goal of this work is to identify the “Achilles heel” in MPN cells treated with JAK2 inhibitors and to target this to eradicate MPN. The benefits are the development of potentially curative treatments for MPN. This study will significantly advance the field of blood cancer research through the development of personalized anti-cancer treatment approaches (i.e. precision medicine) and improve the treatment options for MPN patients.
Grant: 3370-18 | Career Development Program (CDP):
Location:Boston Children's Hospital, Boston, Massachusetts 02241-4413
Project Title: Mechanisms Of Orientation-specific RAG Activity In Mediating V(D)J Recombination And Promoting B Cell LymphomaProject Summary:
A properly functioning human immune system recognizes disease-causing pathogens via a diverse set of antibodies and T cell receptors (TCRs). These molecules, expressed in a subset of white blood cells termed B and T lymphocytes, can bind pathogens and initiate an immune response. The enormous diversity of antibodies and TCRs is generated by the development of lymphoid cells through a DNA “cut-and-paste” process termed V(D)J recombination. The genes encoding the components of the antibodies and TCRs are diversified by the “cutting” and “pasting” of different segments (V, D, and J). The cutting of these gene segments is executed by an enzyme called RAG. Though DNA breaks are required for normal immune development, they can be improperly joined to other DNA breaks across the genome to create mutagenic events that contribute to the development of cancer.
Restricting V(D)J recombination to specific chromosomal loops is critical to prevent RAG from escaping and breaking non-intended targets. Genes are contained in larger structures called chromosomes, which are organized within the cell in a series of large chromosomal loops. Chromosome-bound RAG moves directionally, like a train on a track, to locate its target gene cassettes and only stops when it encounters the roadblocks formed by the loop boundaries. We are studying the nature of the engine that moves RAG along the tracks and how normal RAG "tracking" generates diverse antibody repertoires and minimizes potential collateral damage that could lead to blood cancers. We will use genetically engineered cell lines and mouse models to investigate this process. Our research may provide insights into mechanisms that promote normal immune development and the mechanisms that prevent the potent mutagenic activity of RAG, causing unwanted chromosomal lesions underlying some blood cancers. Our over-arching goal is to identify mechanisms and pathways that suppress tumorigenic lesions in developing lymphocytes and to generate information that can potentially serve the development of new therapeutic targets for lymphoid cancers.
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: 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.
Grant: 6537-18 | Translational Research Program (TRP):
Location:Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
Project Title: Attenuating Oncogenic Myc-driven Transcription Via Modulation Of The Max Heterodimer PartnerProject Summary:
An emerging therapeutic strategy involves controlling the function of overactive transcription factors that regulate the expression of established disease genes in cancer. As transcription factors have historically proven recalcitrant to drug discovery, several labs are pursuing this opportunity by developing indirect inhibitors of transcription that target various chromatin binding factors as well as kinases that play a role in transcriptional initiation. Our lab is focused on discovering and developing small molecules that perturb the function of oncogenic transcription factors by targeting the protein itself or close interacting partners in relevant complexes. We use unbiased binding assays involving small-molecule microrrays to search for compounds that bind to either purified transcription factor, presumably in a highly disordered state, or to protein complexes containing the transcription factor from cell lysates corresponding to various tumors of origin. While our lab is using this approach to identify chemical probes for several transcription factors, roughly half of our group is focused on developing targeted strategies to modulate MYC-driven transcriptional programs. Activation of MYC is one of the most frequent oncogenic events in human malignancies and inactivation of MYC using small molecules may provide a general and effective approach to treating cancer, as MYC is one of the most common drivers of malignancy. Using our screening approach, we identified compounds that bind to c-MYC or its interacting partners such as MAX and found a subset of compounds that modulate a variety of MYC functions in cells, including MYC-mediated transcription. This preliminary data forms the foundation of the studies proposed herein that emphasize advancing the compounds to develop bona fide chemical probes by precisely characterizing their molecular and cellular mechanisms of action as well as synthetically optimizing the compounds with emphasis on improving physicochemical characteristics. Moreover, we propose translational studies involving a lead compound that preliminarily impacts tumor volume in an aggressive murine model of MYC-driven lymphoma. Pursuant to these aims, our lab is comprised of a collaborative, multi-disciplinary team with expertise in methods related to transcriptional profiling, chromatin profiling, quantitative proteomics, computational biology, synthetic chemistry, molecular recognition, and pharmacology. Through these efforts, we hope to build a toolbox of chemical probes that modulate MYC function via different molecular mechanisms and to evaluate these mechanisms as candidates for therapeutic intervention. A key goal for our lab is to make chemical probes and structurally related inactive analogs for MYC and other transcription factors available to the wider research community without encumbrance.
Grant: 6546-18 | Translational Research Program (TRP):
Location:Boston Children's Hospital, Boston, Massachusetts 02241-4413
Project Title: Deciphering Epigenetic Cross-talk In Diffuse Large B-cell LymphomaProject Summary:
With an estimated 73,000 new cases of non-Hodgkin lymphoma (NHL) and 20,000 deaths in the year 2016 alone from NHL, novel therapeutic strategies are urgently required. Specifically, the diffuse large B-cell lymphoma (DLBCL) is the most common form of NHL, and contributes about 30% of new NHL diagnosis every year. Our interest in blood biology, and its mis-regulation is several blood disorders including blood cancers, led us to investigate the role of chemical modifications on one of the most fundamental proteins of like- the histone proteins. We investigated if various histone modifications would be critical for the survival of DLBCL cells. Interestingly, we discovered a unique chemical that specifically abrogates the survival of DLBCL cells but not of any other type of blood cancer cells. We have found that cells commit ‘suicide’ after treatment with our chemical, using a very specific pathway. Furthermore, we have identified a key protein responsible for gene regulation as a likely target of our chemical. This novel target is highly expressed in DLBCL patients, who fare worse after the standard-of-care therapy for DLBCL. Additionally, by performing high throughput gene expression studies, we have identified a completely unique mechanism that bypasses three very frequent mutations found in DLBCL patients, and also explains why our chemical is not very effective against cells that are not coming from DLBCL patients. In essence, we have identified a histone modification pathway that when manipulated kills multiple types of DLBCL cells, but not other types of hematological cancers. We will employ cutting-edge molecular and cell biology, biochemistry, and mouse genetics to carry out specific aims that will a) establish the novel mechanism that allows DLBCL cells to survive. b) Establishes our chemical as a potent strategy against DLBCL through experiments conducted in mouse and c) reveal new details about how histone modifications regulate the formation, and development of B and T cells in humans.
Grant: 6533-18 | Translational Research Program (TRP):
Location:Sloan Kettering Institute for Cancer Research, New York, New York 10087
Project Title: Chemotherapy-Free Targeted Therapeutic Approaches For New And Relapsed Hairy Cell LeukemiaProject Summary:
Classic hairy cell leukemia (cHCL) is a relatively rare form of adult blood cancer that causes massive enlargement of spleen and low white blood, red or platelet cell count. It remains incurable despite high initial response rates to DNA-damaging chemotherapy such as cladribine and pentostatin, and 40% of the patients will experience recurrent disease. In order to develop an effective personalized treatment in these patients, our group previously conducted a clinical trial studying the safety and efficacy of the oral drug called vemurafenib specifically targeting the BRAFV600E mutation that is known to occur in almost all patients with cHCL. In that study, we observed a remarkable overall response rate of 96% in cHCL patients who have failed chemotherapy or experienced recurrent disease. However, we also observed key limitations from the study: 1) vemurafenib alone failed to eliminate all leukemic cells from the bone marrow; 2) disease relapsed in over 30% of the patients; and 3) some patients developed resistant disease, no longer responsive to vemurafenib. These limitations were partly addressed by another recent study that showed adding antibody targeting CD20 called rituximab to vemurafenib significantly improved response rates and more effectively eliminated leukemic cells from bone marrow in patients with relapsed cHCL. However, this promising combination has not been studied in untreated patients who would otherwise receive chemotherapy. Furthermore, vemurafenib is not effective in patients with the related disease called HCL variant (HCLv) and high-risk cHCL that does not carry the BRAFV600E mutation. These disease subtypes tends to be more aggressive, respond poorly to standard therapies, and very little is known about the disease biology. While HCLv does not carry the BRAFV600E mutation, it frequently carries MAP2K1 (MEK1) mutations that may be treated by another oral drug inhibiting its downstream target called ERK. Based on the above findings, we believe that (1) the BRAF inhibitor, vemurafenib, plus a potent CD20-specific antibody, obinutuzumab, will be more effective in eliminating leukemic cells from bone marrow, resulting in more durable responses in patients with previously untreated BRAFV600E+ cHCL and (2) ERK inhibition may be a novel and safe targeted therapy for HCLv and cHCL without the BRAF mutation. Therefore, we propose to develop a comprehensive clinical and laboratory program to study rational, chemotherapy-free, targeted therapeutic approaches in all subtypes of HCL for both untreated and relapsed patients. To this end, we will perform a phase 2 clinical trial of vemurafenib plus obinutuzumab in untreated BRAFV600E+ cHCL patients and, in parallel, a phase 1 clinical trial of the ERK inhibitor BVD-523 in patients with HCLv and relapsed cHCL. In addition, we will perform studies involving mouse models and comprehensive genome profiling of patient samples to understand treatment responses and disease biology.
Grant: 3371-18 | Career Development Program (CDP):
Location:The University of Chicago, Chicago, Illinois 60637
Project Title: Single-cell Technologies To Dissect 5hmC And 5mC Heterogeneity In Normal And Malignant HematopoiesisProject Summary:
Blood cells arise from stem cells found in our bone marrow. Through a process called differentiation, stem cells develop into the diverse blood cell types with their various functions. Cells of the same blood subtype are often thought of as homogeneous populations, but this extreme simplification imposes limitations on our ability to understand normal and malignant blood cells. Therefore, it is critical to understand the more complicated reality of blood cell diversity. Our laboratory is devising cutting-edge strategies to map normal and diseased blood stem cells and differentiated cells in both healthy and diseased situations. These approaches will allow a better understanding of the differences among cells types, within subtypes, and in different pathological contexts, which will provide the basis for therapeutic approaches in the future.
DNA is the molecule that codes for proteins that help provide the functional attributes of cells. DNA is often changed by a process called epigenetic modification. One common form of epigenetic modification is DNA methylation, which can come in different forms, such as 5mC and 5hmC, and can occur at a large number of places in the billions of building blocks of DNA. We hypothesize that a critical component of understanding the identity and function of a cell, whether healthy or diseased, is in the precise characterization of the complex DNA methylation pattern within each single cell. However, stem cells and cells of various differentiated blood cell subtypes are often found in limited numbers. Therefore, the ability to measure 5mC and 5hmC in various cell types, and at a single cell-level, is essential for a more complete understanding of normal and diseased blood cells.
Our single-cell 5hmC/5mC profiling approach will allow us to identify leukemia-specific, differential methylated regions that could harbor known and novel disease-specific target genes, providing quantitative information to precisely reveal methylation changes during normal and leukemic blood cell development. Ultimately, this research will bring us closer to understanding how acute myeloid leukemia develops and how dysregulation of methylation contributes to this process. Our approach will identify promising ways of targeting leukemia cells, facilitating the treatment of this deadly disease.