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: R6507-18 | Translational Research Program (TRP):
Location:Dana-Farber Cancer Institute, Boston, Massachusetts 02215
Project Title: MYD88 And CXCR4 WHIM-like Mutations Offer A Targeted Treatment Approach For WMProject Summary:
Ibrutinib is an active drug that is approved by the U.S. FDA and European Medicines Agency for the treatment of WM. WM patients who have a mutation in MYD88 (over 90% do) respond to ibrutinib, while those with mutations in CXCR4 show lower levels of response and delayed responses. Despite the overall high levels of response to ibrutinib among WM patients, the achievement of complete responses is lacking. We discovered as part of the LLS sponsored study that two important pathways exist by which mutated MYD88 can support growth and survival of WM cells. One pathway is mediated by BTK, a protein targeted by ibrutinib. The other pathway involves a family of proteins known as the IRAK proteins. We discovered as part of this work that the IRAK1 protein was particularly important in relaying survival signals, and that it remains turned on in tumor cells taken from patients with WM, whereas BTK is shutoff. This finding encouraged us to develop potent and selective inhibitors that target IRAK1. One compound that we developed (JH-X-119-01) potently blocked IRAK1, and was very selective for IRAK1. We showed that this compound could synergize with ibrutinib and kill more MYD88 mutated tumor cells, including WM cells and those derived from patients with aggressive lymphomas (ABC type), than Ibrutinib alone. While the activity of this compound is excellent in cell models it does not possess all the requisite parameters for evaluating its efficacy in preclinical murine models. We therefore propose to execute a medicinal chemistry campaign to achieve compounds simultaneously optimized for potency and drug like properties such as resistance to being degraded by liver enzymes and being able to be absorbed across the gut for therapy of MYD88 mutated diseases, including WM, ABC DLBCL, and primary brain lymphomas. During the course of our studies, we also pursued identifying other targets that are in the pathway that allow MYD88 mutated cells to grow. One target known as HCK was discovered that plays a master role as a regulator of many growth and survival pathways including BTK. We performed proof-of-concept studies with a toolbox compound, a compound that blocks HCK but is not suitable for use as a drug in humans, and showed this drug was very active in MYD88 mutated diseases. We propose to do medicinal chemistry to optimize this molecule for use in humans. During our studies, we also discovered that CXCR4 mutations found in 30-40% of WM patients cause resistance to ibrutinib. We worked out the signaling responsible for this resistance, and also found that blockers of CXCR4 reverse drug resistance. We developed a clinical trial that will open in the Spring 2017, and combine a CXCR4 blocker (ulocuplumab) with ibrutinib in WM patients who have the CXCR4 mutation. We will use advanced genetic technologies to see how CXCR4 mutated cells behave when a CXCR4 blocking agent is combined with ibrutinib.
Grant: 1345-18 | Career Development Program (CDP):
Location:The University of Utah, Salt Lake City, Utah 84112-9003
Project Title: MicroRNAs In Myeloid Leukemia Development And Resistance To ChemotherapyProject Summary:
Mutations in genes that control cell growth and survival are commonly found in leukemia. In the case of acute myeloid leukemia (AML) there is often a mutation in a gene called FLT3 that causes it to be activated all the time and promote disease. However, there are many aspects of how this mutated gene is able to promote AML that remain unclear, making it challenging to design and develop new therapies against this devastating condition. My lab studies a newly discovered class of molecules, called microRNAs, which are altered in diseases such as leukemia. In the case of AML with FLT3 mutations, one particular microRNA, called miR-155, is inappropriately elevated and thought to contribute to disease characteristics, including resistance to chemotherapy. Indeed, our preliminary results indicate that when miR-155 is reduced, many symptoms of leukemia that are caused by FLT3 are alleviated in mice and human AML cells growing in a dish. This suggests that miR-155 might work with FLT3 mutations to drive some types of AML in the clinic. We propose to study this relationship in greater detail to understand how these molecules collaborate to cause disease, unveil the mechanisms that are controlled by these genes at the molecular level, and determine if inhibition of miR-155, or other candidate microRNAs, can reduce AML disease in pre-clinical mouse models. Together, this work will provide novel insights into the contribution of microRNAs to different aspects of AML with FLT3 mutations, and hopefully inform the development of next generation microRNA therapeutics that can be used to treat this devastating disease.
Grant: 5468-18 | Career Development Program (CDP):
Location:New York University School of Medicine, Boston, Massachusetts 02241-415026
Project Title: Understanding The Function Of 3D Chromatin Topology In Myeloid DiseaseProject Summary:
Greater understanding of the fundamental mechanisms promoting the development of acute myeloid leukemia (AML) may help researchers develop new treatment approaches targeting these mechanisms. Chromosomes (collections of DNA and their associated proteins) are heritable and dynamic carriers of genetic information. Chromosomes are constantly looping, and these structural changes shape the gene expression pattern of a cell. This 3D genome landscape, known as genome topology, provides the physical structure required to inform the identity and function of a cell. The key players in establishing genome topology include the cohesin complex, a group of proteins that physically wraps around DNA to establish looping events, as well as the CTCF protein, which acts to bind DNA and establish the boundary of genome topological domains. Though genomic topological changes are normal in a healthy cell, alterations in genome topology likely play a role in cancer development.
Interestingly, regulators of genome topology are commonly mutated in various diseases, including cancers such as AML. AML is a common adult leukemia characterized by excessive proliferation of abnormal immature white blood cells. AML patients continue to have a dismal survival rate. Notably, mutations in the cohesin complex are an early step in AML formation, suggesting that controlling DNA looping and overall genome topology is a critical function to prevent cancer. However, there are limited insights into how maintaining the topological integrity of the genome halts AML formation. Our research focuses on understanding how regulators of the genome’s 3D structure protect healthy blood stem cells from forming leukemia. Using cutting edge technology, such as inducible RNA interference and CRISPR/Cas9, we will shed new light into the earliest steps in leukemia formation. Ultimately, mechanistic insights uncovered by these approaches have the potential to inform new treatment strategies targeting the root genetic causes of leukemia development.
Grant: 1351-18 | Career Development Program (CDP):
Location:The Ohio State University, Columbus, Ohio 43210
Project Title: Understanding And Overcoming Resistance To Bruton Tyrosine Kinase Inhibitors In Chronic Lymphocytic LeukemiaProject Summary:
Chronic lymphocytic leukemia (CLL) is the most common adult leukemia and until recently was treated with therapies toxic to the patient. Our clinical and research team at The Ohio State University Comprehensive Cancer Center helped provide critical information which led to the FDA approval of ibrutinib, a less toxic targeted therapy. Ibrutinib inhibits the BTK protein, which is a protein that CLL uses for its own pathological survival. Ibrutinib shows remarkable clinical activity that is more durable than any therapy ever studied in CLL. Unlike some CLL treatments, ibrutinib can be given to all age groups, making it a more widespread therapy. Ibrutinib’s success should form the basis for its inclusion in even more effective combination therapies that may someday lead to a cure. Historical experience indicates that effective new therapeutics for CLL will also have a major role in treatment of non-Hodgkin lymphoma and autoimmune diseases.
While ibrutinib is effective for many patients, some develop resistance to this treatment. My research team seeks to determine predictive genomic factors that result in BTK inhibitor therapy resistance. We discovered that some patients acquire mutations that then confer resistance to ibrutinib. The large group of patients treated with ibrutinib, including our collection of samples from patients with resistance mutations, represents an invaluable resource to pursue pre-clinical and clinical work to identify more effective CLL treatments. Exploring the mutations and their associated signaling pathways (which we will continue to discover) will help us understand ways to overcome treatment-related resistance by either early recognition or, potentially, novel therapeutic approaches.
Our experiments use primary CLL cells from patients whom are seen by our clinical team. We are also using the most appropriate laboratory-based model available for understanding preclinical drug development and CLL biology. Our experimental approach will directly address the Leukemia & Lymphoma Society’s mission to cure blood cancer by discovering new potentially curative treatment strategies for CLL.
Grant: 3374-18 | Career Development Program (CDP):
Location:Brigham and Women’s Hospital, Boston, Massachusetts 02241-3149
Project Title: Functional Characterization Of The Mutant Calreticulin-MPL Interaction In Myeloproliferative NeoplasmsProject Summary:
Myeloproliferative neoplasms (MPN) are a group of rare blood cancers that occur when the body produces too many white blood cells, red blood bloods, or platelets. Though the overall prognosis for MPN tends to be favorable, more advanced forms of these diseases can lead to severe anemia, increased risk of blood clots, and transformation to leukemia. MPN were first described in 1951 by hematologist William Dameshek, but the underlying genetic cause of these diseases remained a mystery for over 50 years. In 2005, four different research groups simultaneously discovered that approximately 63% of MPN patients harbor mutations in the gene JAK2. This was a tremendous breakthrough in the MPN field and led to the development of the FDA-approved drug ruxolitinib (Jakafi), a compound that inhibits JAK2 activity, for the treatment of MPN. Despite this advance however, the causal genetic abnormalities in the remaining 40% of non-mutated JAK2 MPN patients remained unknown for nearly a decade thereafter. In 2013, two different groups performed sequencing experiments on blood cells from non-mutated JAK2 MPN patients, and found that the majority of these patients harbor mutations in the gene calreticulin (CALR). The CALR gene encodes a “housekeeping” protein that resides in the endoplasmic reticulum (ER) and ensures quality control of protein folding in the cell. We currently have an incomplete understanding of the mechanism by which CALR mutations transform normal blood cells to cause MPN.
Unlike normal CALR, mutant CALR is found near the cell surface. Our recent research has shown that the mutations enable an interaction with a cell surface receptor protein called MPL. We have further shown that this interaction leads to an activation of the JAK2 pathway. A central hypothesis from this research is that mutant CALR binds to proteins that it does not normally bind to, and some of these proteins may be essential for the oncogenic activity of CALR. Building on this work, we will utilize state-of-the-art technology to determine the proteins mutant CALR binds to in the cell that are not bound by normal, non-mutated CALR. Through this work, we hope to gain a comprehensive understanding of the protein partners with which mutant CALR interacts in the cell to drive disease development, which would ultimately inform new targets for therapeutic intervention. Ultimately, we hope that our work will lead to improved therapeutic strategies for MPN patients, particularly those who do not respond well to ruxolitinib and other existing treatments.
Grant: 5461-18 | 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: The Role Of NOTCH1 Controlled Micropeptides In T-ALLProject Summary:
Acute lymphoblastic leukemia (ALL) is the most common form of pediatric cancer and a leading cause of disease-driven death in children. Understanding the causes and mechanisms of leukemia is essential in order to develop specific highly active and less toxic treatments. One of the most common drivers of leukemia growth and survival is the NOTCH1 gene. NOTCH1 is frequently mutated in leukemia, and these mutations cause increased NOTCH1 activity, which in turn triggers a cellular program driving uncontrolled cell proliferation. Our understanding of the specifics of how NOTCH1 promotes leukemia transformation remains rudimentary.
Though most of our knowledge of T-ALL comes from the genetic dissection of known protein-coding genes, it is likely that other components of the genome contribute to T-ALL as well. A recently discovered component of the genome gives rise to very small proteins, called micropeptides that likely have profound effects on gene expression. Our research aims to investigate the role of this new family of gene-encoding proteins as potential key drivers of leukemia growth. Our central hypothesis is that among the multiple proteins controlled by NOTCH1, micropeptides are of particular importance for leukemia growth and survival. While large proteins function as molecular machines, micropeptides function as keys or switches that bind to and turn these molecular machines “on” and “off”. We are using the latest genomic technologies and refined computational approaches to identify the complete repertoire of NOTCH1-controlled micropeptides operating in leukemia. We will then evaluate the specific role and mechanisms by which these short proteins contribute to leukemia cell growth. Dissecting the mechanism of action of these key leukemia-driving micropeptides may identify novel targets for the treatment of ALL.