Grant: 5473-18 | Career Development Program (CDP):
Location:Broad Institute, Inc., Cambridge, Massachusetts 02142
Project Title: Probing The Translatome For Neoantigens In Chronic Lymphocytic LeukemiaProject Summary:
Our cells display on their surface a snapshot of their protein repertoire processed and presented in the form of antigens. Antigens are recognized by the immune cells, which assess whether the antigens are known or foreign and mount an immune response against cells with foreign antigens. DNA mutations in cancer cells produce mutant proteins, presented as neoantigens on the cancer cell surface. The immune cells recognize neoantigens as foreign and attempt to mount an immune response against these cancer cells. Recently approved immunotherapy drugs boost this immune response and show great promise in the clinic, but the response is often non-specific and may affect healthy tissues, resulting in autoimmunity. Thus, directing the immune cells to defend against specific neoantigens will further boost the immune response and minimize autoimmunity. However, identifying and selecting neoantigens to target remains challenging.
Putative neoantigens are commonly predicted by sequencing and identifying mutations in the exons (molecules which mostly contain information coding for amino acids) of a given genome. This approach is generally sufficient for cancers characterized by many DNA mutations. However, some cancers, such as chronic lymphocytic leukemia (CLL) accumulate fewer DNA mutations, resulting in fewer predicted neoantigens. Since exons represent about 1% of our genome and mutations can be found anywhere in the genome, we have the opportunity to identify previously unknown neoantigens that are generated from mutations outside of the exons. Using next generation sequencing technologies and computational tools, we will expand the neoantigen search beyond currently known genes, maximizing our chances at identifying neoantigens to target. The expanded search for neoantigens will broaden potential targets for therapy for CLL. Importantly, the computational approaches we are developing may be useful beyond CLL and may be used to identify novel neoantigens in any cancer, particularly those with low mutation load.
Grant: 5467-18 | Career Development Program (CDP):
Location:Walter & Eliza Hall Institute of Medical Research, Parkville 3050, Victoria
Project Title: The Key To Cancer Cell Death; Regulation Of The Pro-apoptotic Protein BIMProject Summary:
Treating blood cancer patients with conventional approaches remains unsatisfactory because the cancer often recurs and because of the undesirable side effects caused by many of the treatments currently offered. By improving our understanding of the genetic basis of hematopoietic malignancies, we can develop targeted agents that are more selective in their action against tumor cells.
In healthy organisms, many cells have a finite lifespan. These cells undergo a normal, programmed cell death process called “apoptosis” and are then replaced with new cells. Apoptosis is regulated by a number of proteins, including pro-apoptotic proteins, such as BIM and anti-apoptotic proteins, such as BCL2. A prominent hallmark of many leukemias and lymphomas is their inability to undergo apoptosis, allowing them to survive indefinitely. Research at my host institution contributed to the development of venetoclax, an inhibitor of the pro-survival protein BCL2, which treats cancers by restoring their ability to undergo cell death. In chronic lymphocytic leukemia (CLL), a leukemia where BCL2 is overactive, remarkable results have been achieved in clinical trials, recently leading to FDA approval of the drug for treatment of patients with high-risk CLL. Since different tumor types may express different apoptotic regulators, the results with venetoclax suggest that targeting apoptotic regulators specific to a tumor type may lead to better patient outcomes in a number of different cancers.
In mantle cell lymphoma (MCL), a disease related to CLL, expression of the pro-death molecule BIM is suppressed in 20% of patients. Thus, restoring BIM expression should sensitize these cells to undergo cell death, which may be particularly beneficial in combination with standard-of-care chemotherapeutic agents or the BCL2 inhibitor. This combination therapy may result in greater cell death and thus an enhanced therapeutic benefit. Though the role of BIM in regulating cell death is well-described, it is less clear how levels of BIM are regulated in normal cells or how BIM is suppressed in MCL. The focus of my research is to unravel the molecular mechanisms by which the expression of pro-death molecules, such as BIM, is controlled. I anticipate that the results I obtain could help explain how hematopoietic cancer cells can evade cell death and potentially lead to the development of novel approaches to treat these malignancies more effectively.
Grant: 3373-18 | Career Development Program (CDP):
Location:Emory University, Atlanta, Georgia 30322-4250
Project Title: Tetrameric Acetyltransferase ACAT1 Is A Novel Therapeutic Target In Treatment Of Human LeukemiaProject Summary:
Tyrosine kinases (TKs) are a group of proteins that serve as "on/off" switches to control various cellular functions. When TKs are continuously turned on (“activated”) in blood cells leukemia may result. Anti-leukemia drugs that are designed to target TKs in leukemia cells are widely used in clinics. However, many patients develop resistance to these drugs over time, making them less effective or not effective at all. Thus, it is critical to find alternative therapies to battle drug resistance and improve clinical outcome. Cancer cells, including leukemia cells, consume more sugar compared to normal cells. However, unlike normal cells that use glucose primarily for energy, cancer cells use glucose primarily to generate the “building blocks” of proteins and lipids, enabling the cancer cells’ rapid division rate. A protein complex called pyruvate dehydrogenase complex (PDC) functions as a “gatekeeper” to control the flow of sugar toward either energy generation or building block production. When the PDC is “closed,” such as in leukemia cells, most glucose will go towards the production of building blocks. Thus, finding out how PDC activity is inhibited in leukemia cells may uncover a new vulnerability of human leukemias.
Our previous research showed that a protein called acetyl-CoA acetyltransferase 1 (ACAT1) can significantly inhibit PDC activity. Our current studies show that ACAT1 can be highly activated in leukemia cells by TKs through a chemical modification called tyrosine phosphorylation, resulting in a more stabilized and activated form of ACAT1. Most importantly, we found that ACAT1 is more activated in leukemia patients than in healthy people, resulting in further PDC inhibition. Thus, we think ACAT1 is a promising anti-leukemia drug target. By screening FDA-approved compounds, we successfully identified a novel ACAT1 inhibitor called Arecoline Hydrobromide (AH). Our results showed that AH can effectively inhibit leukemia cell growth. We will perform further studies to gain a detailed understanding of how AH inhibits PDC, and we will test AH potency in various leukemia cell lines, animal models, and leukemia patient samples. We will also work with expert chemists to develop new ACAT1 inhibitors, related to AH, but with improved potency. Altogether, this research will provide new insight into anti-leukemia drug design, help identify new novel drug targets, and ultimately uncover novel therapeutic approaches in blood cancers.
Grant: 8012-18 | Screen to Lead Program (SLP):
Location:H. Lee Moffitt Cancer Center & Research Institute, Atlanta, Georgia 30374-2801
Project Title: Rationally Designed Dual BRD4-Kinase Inhibitors For The Treatment Of Myeloid CancerProject Summary:
Current anti-cancer targeted drugs often fail due to ineffectiveness or drug resistance, suggesting alternative strategies are needed to develop effective therapies. We recently determined that certain drugs bind to and inhibit two different classes of proteins that play important roles in cancer. These two classes are called kinases and BET proteins, which have completely different functions in the cell. The general approach in drug discovery has been to optimize a single drug to target a single protein. Our identification of the dual inhibitory activity of BET-kinase inhibitors provides an opportunity to optimize inhibiting both targets with a single drug. To this end, we have developed drugs that exhibit improved kinase and BET inhibitor activity. The ability of these compounds to target multiple regulators of cancer may provide superior effectiveness against blood cancers that are known to require both targets of the drug. For example, one of the dual inhibitors targets the JAK2 kinase, which is a major driver of myeloid cancers. JAK2 kinase inhibitors, which have been designed to solely target kinase activity, have not been successful in patients due to ineffectiveness and drug resistance. As these cancer cells also require BET protein function, our dual inhibitors may improve effectiveness and prevent drug resistance, a concept support by our initial studies. This proposal is written to support our optimization and development of our lead compounds for blood cancers.
Grant: 5474-18 | Career Development Program (CDP):
Location:The University of Chicago, Chicago, Illinois 60637
Project Title: Transcriptional And Epigenetic Roles For β-catenin In The Genomic Instability And Oncogenic Transformation Of T-cell Leukemia/lymphomaProject Summary:
Cancer arises from changes in DNA, and these changes can come in various forms. In the case of leukemia and lymphoma, most have genomic instability, meaning the normal organization of DNA (the genome) is disrupted due to improper repairing of DNA breaks. DNA is organized into structures known as chromosomes, and changes to normal chromosomal structure is evidence of genomic instability in a cell. Chromosomal defects mark approximately 80% of T-cell leukemia and often involve the moving of cancer-causing genes to other chromosomes (translocation) into positions that switch them “on.” This instability of the genome is a continuous process and allows for selection of ever more aggressive and therapy-resistant tumor cells. Our protein of interest, beta-catenin, has very tightly controlled, low expression levels in normal cells; however, uncontrolled beta-catenin expression has been linked to genomic instability in cancer through mechanisms that remain unclear.
Previous work from our lab showed that uncontrolled beta-catenin expression causes mice to develop T-cell leukemia. These leukemias have genomic instability and chromosomal defects similar to those seen in T-ALL patients. The pattern of DNA breaks suggests that the excess beta-catenin impairs mechanisms (known as checkpoints) that ensure that DNA is replicated and repaired correctly. In fact, these mice have lower than normal expression levels of genes required for DNA checkpoints and repair. Based on observations of this model, I hypothesize that beta-catenin affects multiple levels of gene regulation to impair DNA checkpoints and repair. Beta-catenin controls transcriptional mechanisms of gene expression, which switch genes “on” or “off,” as well as epigenetic mechanisms, which change the shape of DNA to allow various kinds of gene regulators to interact. Using state-of-the-art genomic technologies, I will examine DNA checkpoint and repair mechanisms to understand both transcriptional and epigenetic changes that happen in cells with uncontrolled beta-catenin. I will also examine cells from leukemia patients to apply what I see in my mouse model to human disease.
Chromosomal defects are a driving force in cancer and reflect a fundamental failure of the checkpoints that maintain genome integrity. My goal is to increase our understanding of how beta-catenin controls these intricate cellular processes. My studies aim to identify novel strategies for the treatment of this complex blood cancer.
Grant: 6545-18 | Translational Research Program (TRP):
Location:Brigham and Women’s Hospital, Boston, Massachusetts 02241-3149
Project Title: Targeting Notch In B Cell Lymphoma/leukemiaProject Summary:
Remarkable progress has been made in the treatment of CLL and other B cell tumors such as mantle cell lymphoma, but to date none of these treatments result in cures, and new therapies are needed. Our group has a longstanding interest in targeting the Notch pathway as a cancer treatment strategy. Recently, mutations in Notch genes have emerged as being among the most important causes of CLL and other B cell tumors. These mutations result in Notch “hyperactivity” and are associated with more aggressive disease; thus, patients with tumors with Notch mutations are particularly in need of new therapies. Our proposed work is focused on the idea that even in tumor cells with Notch mutations, Notch activation depends on neighboring cells that express proteins called ligands that turn on Notch. The precise identity of these ligands is not known, but drug companies have developed therapeutic antibodies that specifically inhibit several known Notch ligands, including those that we think are responsible for Notch activation in B cell tumors. Our proposed studies aim to identify the ligand that is causing Notch activation in B cell tumors, to determine the reason that Notch causes B cell tumors to behave more aggressively, and to prove that Notch inhibitors, alone and in combination with other drugs currently used to treat CLL and other B cell tumors, are effective in killing tumor cells. Taken together, these studies will set the stage for new clinical trials of Notch inhibitors in patients with B cell tumors.
Grant: 6547-18 | Translational Research Program (TRP):
Location:The University of Adelaide, Adelaide, South Australia 5000
Project Title: Targeting Stromal Cell-derived Gremlin1 To Control Multiple Myeloma Disease DevelopmentProject Summary:
Multiple myeloma (MM) is a bone marrow (BM) cancer of antibody producing plasma cells (PC). MM PCs are thought to spread throughout the BM in a manner similar to the way in which solid tumours spread. However, which cells and/or factors within the BM are important in helping PCs establish and grow, remains largely unknown. Using newly developed microscopic and genetic marking techniques: we have shown that there are very few sites within the BM that are capable of supporting the growth of PC tumours. In fact, we have found that the majority of the PCs that migrate to, and “land” in the BM remain “dormant” and fail to grow. These findings suggest that in order to grow, MM PCs must encounter an environment that has the right type of cells and factors, which support their growth. We believe that a rare type of cell, called an osteochondroreticular stem cell (OCR-SC), which we recently discovered, plays an essential role in “switching on” the growth of MM PC. OCR-SCs are unique in their ability to make a protein called Gremlin 1 (Grem1), which has been shown in other types of cancer, to stimulate tumour growth. Our early studies show that Grem1 can potently stimulate MM PC growth and that very high levels of Grem1 are found in areas of the BM that are occupied by tumour. We have assembled a team of experienced researchers with unique skills and established relationships with industry to enable us to investigate whether inhibiting Grem1 activity can provide a way to limit the growth of MM PC and prevent MM disease development.
1. We will use a technique known as laser scanning cytometry (LSC) and BM samples from patients with a asymptomatic forms of MM known as monoclonal gammopathy of unknown significance (MGUS) or smouldering MM (SMM) and samples from patients with MM, to determine whether Grem1-expressing cells are found in areas of active tumour growth, and not in areas in which the PC remain dormant. Similarly, we will use LSC to examine the bones from mice in which we have induced a MM-like disease to show that Grem1-expressing OCR-SCs are a key component of the “activating” areas of BM which support MM PC growth.
2. We will use genetically altered mice, in which Grem1 has been removed from OCR-SCs, to show without doubt, that Grem1 is required for the growth and development of MM. In addition, we will inject an antibody that blocks the function of Grem1 into mice with MM, to see if this will lead to MM PC tumour death or dormancy. These studies will be the first important steps to see if Grem1 is a good therapeutic target to stop disease development in MM patients.
3. We will measure the levels of Grem1 in the blood in a large number of samples that we have collected from patients with MGUS, SMM or MM. This will allow us to determine if Grem1 levels are associated with the amount of disease a patient has, or whether Grem1 levels predict the risk of a patient with benign disease developing advanced disease.
Grant: 6538-18 | Translational Research Program (TRP):
Location:The Ohio State University, Columbus, Ohio 43210
Project Title: Novel Strategies For The Therapy Of Genomic High Risk CLLProject Summary:
Cancers such as chronic lymphocytic leukemia (CLL) are characterized by a slow accumulation of a specialized kind of white blood cell called a B-lymphocyte. It starts in the bone marrow and spills over to accumulate in the blood, lymph node, liver and spleen. The reason CLL is problematic is that the leukemic B-cells are non- functional and live for a long time either because they have proteins that help them survive for a long time or lose proteins that normally would cause them to die.
CLL undergoes changes in its genes. For instance, it often loses a very important gene called p53. p53 is called the guardian of the genome and is necessary to kill the CLL cells after treatment with drugs. Every cell of the body has two copies of this gene. In CLL, one copy of p53 is lost due to deletions and the other copy sometimes gets altered by mutations. The mutated p53 supports the survival of the CLL cells and help the disease become resistant to treatment. Both deletions and mutations of p53 have been found to decrease survival in patients whose CLL cells carry these abnormalities.
Mutated p53 depends on HSP90, a protein that binds to mutated p53 and helps it carry out its cancer supporting function. One of the key functions of mutated p53 is to block the cell death inducing action of normal p53 and in addition activate other genes that support CLL cell survival. We plan to use drugs that stop the action of HSP90 (HSP90i). Blocking HSP90 will prevent it from stabilizing mutated p53 and cause it to be destroyed, which in turn, will kill CLL cells that carry deletions or mutations of p53. Therefore, HSP90i treatment may represent a new treatment that can treat this poor prognosis group of CLL patients (del17p/mutant p53) either alone or in combination with drugs such as ibrutinib that are currently in use used to treat the disease.
Grant: 6553-18 | Translational Research Program (TRP):
Location:IRIC - Institut de Recherche en Immunovirologie et en Cancerologie, Montreal, Quebec H3C 3J7
Project Title: RUNX1 Mutations That Confer Exquisite Sensitivity To GlucocorticoidsProject Summary:
Acute myeloid leukemia (AML) is a disease caused by several genetic alterations, including mutations in the RUNX1 gene. The presence of RUNX1 mutations in AML cells is generally associated with bad prognosis for these AML patients, and RUNX1 mutations are also the cause of Family platelet disorder, which predisposes these patients to AML development. In order to discover novel cures for patients suffering from RUNX1-mutated AML, we identified glucocorticoids as effective drugs that kill AML cells carrying RUNX1 mutations. In this proposal, we plan to perform experiments to better understand how these molecules kill these AML cells and test the ability of GCs to cure mice that we will engineer to develop AMLs harboring RUNX1 mutations, in the hope of bringing this discovery to the clinic to improve treatment of patients suffering from RUNX1- mutated AML.
Grant: 5471-18 | Career Development Program (CDP):
Location:Harvard Medical School, Boston, Massachusetts 02241-5649
Project Title: Studying The Function Of Co-activator MAML1 In Notch-associated T-cell Acute Lymphoblastic LeukemiaProject Summary:
Normal cell growth and differentiation relies on a small number of signaling pathways that direct the gene expression patterns unique to each cell type. One pathway particularly important in cell-cell communication is the Notch pathway, which normally relies on direct contact between a signal-sending cell and a signal-receiving cell. After the signal is activated, a portion of the Notch protein enters the cell nucleus and forms a complex with two other proteins, called RBPJ and MAML1, to regulate the expression of genes that control cell growth and cell fate decisions. Aberrant activation of the Notch pathway by mutations, however, leads to the development of T cell acute lymphoblastic leukemia (T-ALL). In fact, Notch1 mutations are found in more than half of all human T-ALL cases. The goal of my project is to understand how the MAML1 gene cooperates with Notch to induce the production of Notch-responsive genes. In one line of study, I will use a Notch inhibitor to toggle the Notch pathway between “on” and “off” states, and determine what protein partners MAML1 chooses in the “Notch active” state and how these partnerships affect its function. I will also analyze the temporal sequence of events that take place in the nucleus after Notch is switched on in leukemic cells, focusing on the role of MAML1 in the induction of target gene expression. These studies will help us understand how Notch and MAML1 cooperate to stimulate aberrant gene expression in leukemic cells and may lead to new strategies for therapeutic development in T-ALL.