Kevin D. Mills - US grants

[unreadable] DESCRIPTION (provided by applicant): The objectives of this study are to determine functional roles for recurrent cytogenetic lesions in a mouse B lymphoid cancer model, and to elucidate the mechanisms for formation of characteristic karyotypic instability. While genomic instability is a recognized hallmark, many tumors, including lymphomas and leukemias, the molecular mechanisms behind genomic instability, as well as its consequences, are poorly understood. Cytogenetic abnormalities affecting chromosomes 4q21 or 11q23 are common in lymphoid malignancies, such as mantle cell lymphoma and preB-ALL, the latter being the most common pediatric malignancy, at nearly 25% of all childhood cancer diagnoses. Translocations involving 11q23, producing oncogenic fusions of the MLL gene with numerous possible partners, are common; other abnormalities, such as amplification at 4q21 and/or deletion of 11q23, though less frequent, also occur. Rearrangements at 11q23 generally predict a poor prognosis, especially in infant B-ALL patients, and malignancies with deletions at 11q23 tend to exhibit greater karyotypic instability than those with balanced translocations in the same region. Deletions at 11q23 are also associated with Richter's syndrome, characterized by the transformation of chronic lymphocytic leukemia to high-grade non-Hodgkin's Lymphoma (NHL). Richter's syndrome leads to accelerated tumor growth, clinical deterioration, and resistance to conventional therapy. Emerging evidence suggests that defects in DNA double strand break repair can lead to oncogenic genome instability and, in support of this notion, mutations in DNA break repair factors are implicated in a number of human tumors, including Richter's syndrome. Mice deficient for any of the six known components of the nonhomologous end joining pathway of DNA break repair, and for the tumor suppressor p53 (encoded by Trp53; collectively referred to as NHEJ/Trp53 mice), develop aggressive, multi-focal progenitor (pro)-B cell lymphomas with extremely high penetrance. Strikingly, copy number abnormalities (CNA) observed on chromosomes 5 (CNA5) and 9 (CNA9) in Lig4/Trp53 tumors affect regions related to human 4q21 and 11q23, respectively. Thus, NHEJ/Trp53 mice provide an animal model for lymphoid cancers with CNA-type lesions at these chromosomal locations, and will yield insights into currently unknown facets of human lymphoid cancers, such as childhood B-ALL and Richter's syndrome. These studies will therefore lay a foundation for the development of improved diagnostic methods, as well as the formulation and clinical development of new, possibly individualized, therapeutic approaches. [unreadable] [unreadable] [unreadable] [unreadable]

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. DNA breaks are critical for many cellular and developmental processes, but must be correctly repaired to prevent genome instability. The objectives of this project are to understand the roles of DNA double strand break repair (DSBR) in normal hematopoietic development, and to determine whether DSBR defects in specific cell types in the bone marrow may relate to cancer development. DSBR is known to be a key factor in lymphoid tumor suppression, but has been less well characterized in other cell types. I hypothesize that DSBR is critical in both hematopoietic cells and their surrounding microenvironments to promote normal development and prevent neoplastic transformation. Using mice deficient for DSBR, with or without the tumor suppressor p53, we will test this hypothesis by measuring the fitness and function of normal hematopoietic stem, progenitor, and progeny cells;and by evaluating tumorigenicity in DSBR competent or defective bone marrow and lymphoid microenvironments. Aim 1. To evaluate the extent to which NHEJ is required for normal function or homeostasis of cells in the hematopoietic compartment, we will: (1) test whether DSBR-deficient HSCs or their descendants are impaired for differentiation or function and (2) measure genome instability in DSBR-deficient stem and progenitor cell populations Aim 2. To determine whether specific stem cell or lymphoid microenvironments participate in shaping the lymphoma phenotype, we will: (1) determine whether tumorigenesis is differentially influenced by lympho-competent versus lympho-deficient bone marrow microenvironments;and (2) test whether tumor cells become adapted to specific secondary lymphoid microenvironments

DESCRIPTION (provided by applicant): The objectives of this proposal are to determine the roles for homologous recombination in genome stability, tumor suppression, and normal development. Chromosomal instability is a major hallmark of many cancers, and chromosome aberrations can be important prognostic markers, with greater instability usually corresponding to poorer outlook. Unfortunately, the underlying molecular mechanisms that prevent or promote chromosomal instability remain largely unknown. Growing evidence implicates unrepaired DNA double strand breaks (DSB) in genome instability. Homologous recombination (HR) represents one critical DSB repair pathway that may be especially important as cells are multiplying. Our central hypothesis is that homologous recombination is crucial for preventing cancer-related genome instability in rapidly dividing cells. We will test this hypothesis by focusing on the function of one important HR pathway component, XRCC2, in lymphocytes. Using a lymphocyte culture system amenable to both in vitro and in vivo studies, we recently showed that XRCC2 is required for normal B-cell development. We will employ this same system to now carry out the specific aims of: 1) Testing the extent to which XRCC2 prevents replication-associated genome instability and tumorigenesis. Using both in vitro and in vivo approaches, we will test Xrcc2-defective cells for spontaneous or induced chromosomal abnormalities, and measure the effects of Xrcc2-deficiency on tumor suppression. 2) Defining the mechanisms of interaction between XRCC2 and the p53 protein. Our data indicate a genetic interaction between Xrcc2 and the gene encoding p53 (Trp53). We will use multiple approaches to test whether this involves direct or indirect physical interaction of the proteins. 3) Measuring the functions of XRCC2 in normal lymphocyte development. Our data suggest that XRCC2 has critical functions, not just in preventing genome instability, but also in promoting normal lymphoid development. To better understand the mechanisms of tumor suppression, we will precisely define the normal lymphoid developmental roles of XRCC2, using in vitro and in vivo approaches. This work will be essential to understanding the molecular origins of chromosomal abnormalities and how they may function to drive cancer development. PUBLIC HEALTH RELEVANCE: Chromosome aberrations are a hallmark of human cancer, and can be useful indicators of patient prognosis. In this proposal we will investigate the origins of cancer-related chromosome aberrations and the mechanisms by which they occur. Identifying these mechanisms will be key to designing better cancer diagnostic tests;refining prognostic markers;and developing new cancer therapies based on tumor-specific properties.

DESCRIPTION (provided by applicant): Cancer is a genetically complex and biologically heterogeneous group of disorders. It has become increasingly clear that the laboratory mouse, the best genetically defined experimental model organism for humans, presents a major opportunity for rapid advancement in understanding the genetic basis and underlying biology of cancer. The overall goal for our course is to train young scientists (predoctoral, postdoctoral trainees, new investigators) in the use of genetically defined laboratory mice as genetic tools for asking questions about gene function and the role of genetics in the biology of cancer. Students completing the course will acquire a working knowledge of: (1) mouse genetics and genomics, (2) growth control and cancer, (3) experimental design and the application of statistical genetics to complex trait analysis, (4) bioinformatics, (5) animal health and ethical considerations in working with mice, (6) basic mouse surgical techniques, and (7) mouse models for human cancer. How the mouse is used in the translation of basic research to the clinic will be emphasized. These Aims will be accomplished by offering an intensive 10-day course to 35 young investigators chosen for their outstanding research potential. They will interact with a group of prominent mouse geneticists and cancer biologists both from The Jackson Laboratory and other prominent institutions. The size of the class will be kept deliberately small in order to achieve a desirable level of student-faculty interaction. The course will be held annually during the last tw weeks of August at Highseas, The Jackson Laboratory's residential oceanfront conference facility. Lectures, discussions, workshops, and demonstrations will be held morning, afternoon, and evening for a total of approximately 72 hours of didactic and hands-on training. We are asking for a full five years of support in this application. The Jackson Laboratory is an NCI-designated Basic Research Cancer Center and has a long history of hosting advanced courses and scientific meetings. The annual short course on the Experimental Models of Human Cancer described in this application has been held annually since 1992.

? DESCRIPTION (provided by applicant): Genomic instability is a hallmark of cancer, and represents a targetable vulnerability, yet is underdeveloped as a therapeutic area. The central goal of this Phase 2 program is to complete the early preclinical development of a new class of new cancer therapeutics that uniquely target RAD51, delivering effective cancer-cell selective therapy in subsets of biomarker-defined leukemia and lymphoma. Two key challenges in current cancer therapy are overcoming tumor cell evolution that drives cancer progression and therapy resistance; and minimizing the side effects due to off-target toxicity. Therapies that target genomic instability mechanisms have the potential to meet these critical clinical challenges. In recent years, the B-cell specific DNA mutase/recombinase Activation Induced Cytidine Deaminase (AID) has been implicated as a driver of oncogenic genomic instability. While its expression is normally restricted to activated, germinal center B-cells, AID is also overexpressed in a range of human neoplasms, especially B-cell non-Hodgkin's lymphomas (NHL) and chronic lymphocytic leukemia (CLL). Cyteir Therapeutics, Inc., in partnership with The Jackson Laboratory, has demonstrated the feasibility of targeting RAD51 in these cancers and has developed new lead candidate compound. Our novel therapeutic approach takes advantage of the discoveries that: (1) AID is both a biomarker and a DNA damage driver, creating widespread DNA double strand breaks (DSBs) throughout the genome; and (2) RAD51 has a unique role in the repair of these malignant, AID-induced DSBs and is, therefore, critical for viability in transformed, AID+ cells. Cyteir's lead RAD51 inhibitor is potent, highly selective for cells that are AID+, effective against NHL and CLL cells in vitro and in vivo, and is extremely well tolerated in preclinical animal models. The aims of this Phase 2 study are to complete early preclinical testing and development required prior to the filing of investigational new drug (IND) application and commencement of phase I clinical trials. We will develop a clinical dosage form for our lead compound, carry out single- and multiple-dose tolerability and range finding studies, establish pharmacokinetics and toxicokinetics for the clinical dose form, and generate comprehensive comparative efficacy data using human- to-mouse xenograft models of NHL and CLL. We have assembled an impressive team of academic and industry leaders, complemented by an advisory panel of top thought leaders, to advance this program and build the Cyteir drug discovery engine. One of our strengths is the continuing partnership with The Jackson Laboratory, providing both an academic foundation for our R&D efforts and a platform of unique in vivo testing technologies to enable rapid translation to the clinical phase. Our commercialization plan for this program calls for completion of the proposed preclinical studies, commencement of clinical trials and partnership or out licensing after either phase I or phase II trials, to create company and investor value and generate revenue to continue building a sustainable drug development pipeline.

PROJECT SUMMARY/ABSTRACT Cancer is a genetically complex and biologically heterogeneous group of disorders. It has become increasingly clear that the laboratory mouse, the best genetically defined experimental model organism for humans, presents a major opportunity for rapid advancement in understanding the genetic basis and underlying biology of cancer. The overall goal for our course, Workshop on Techniques in Modeling Human Cancer in Mice, is to train a small group of young scientists (predoctoral, postdoctoral trainees, new investigators) in the use of genetically defined laboratory mice as genetic tools for asking questions about gene function and the role of genetics in the biology of cancer. Students completing the course will acquire a practical knowledge of how to characterize and analyze specific mouse cancer models. The models chosen will reflect several organ sites including colon, prostate, mammary, lung, skin, blood and brain. The course will consist of didactic lectures in the morning to introduce particular organ sites and the characteristics of cancers associated with those organ sites, followed by intensive laboratory sessions whereby students will gain hands on experience in the manipulation and analysis of relevant mouse models. Sessions will include fixed and live cell imaging techniques, cytometry, surgical approaches to the implantation of tumors, and pathology. These Aims will be accomplished by offering an intensive 10-day course to 16 young investigators chosen for their outstanding research potential. They will interact with a group of prominent mouse geneticists and cancer biologists both from The Jackson Laboratory and other prominent institutions. The size of the class will be kept deliberately small in order to achieve a desirable level of student-faculty interaction and to permit extensive laboratory training and practice for the students. The course will be held annually during the month of October at Highseas, The Jackson Laboratory's residential oceanfront conference facility. Lectures, discussions, workshops, and demonstrations will be held morning, afternoon, and evening for a total of approximately 72 hours of didactic and hands-on training. We are asking for a full five years of support in this application. The Jackson Laboratory is an NCI-designated Basic Research Cancer Center and has a long history of hosting advanced courses and scientific meetings.