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Organization of the Organ Systems Branch Current SPORE Programs Information for the Public PART Program Information for Applicants IntraSPORE Communications
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Johns Hopkins SPORE in Breast Cancer Nancy E. Davidson, MD
Project 1A - "Molecular Markers for Breast Cancer" The overall goal of this project is to identify major molecular alterations in carcinoma of the breast since, in marked contrast to a number of other cancers, the molecular events leading to breast cancer remain unknown in all but a small minority of cases.
Project 1B - "Molecular Phenotypes of Breast Cancer" The majority of breast cancers are diagnosed as breast cancer of no specific type (or ductal carcinoma), a heterogeneous category of tumors that includes curable neoplasms as well as highly aggressive cancers. This classification is inadequate for clinical management of breast cancer patients as well as for designing laboratory and clinical research protocols. Although there are clearly a number of different tumor phenotypes within this diagnostic category, traditional morphology and even current molecular markers of prognosis are incapable of clearly discriminating different subtypes of ductal cancer from one another. In this project, we, propose to distinguish biologically different groups of ductal breast cancer from one another using gene expression profiles. This is based on the concept that gene expression profiles represent an objective and quantitative measure of a neoplasm's phenotype. We have in preliminary experiments identified a number of genes that are differentially expressed among different ductal cancers, consistent with our hypothesis that different breast cancer phenotypes are associated with different gene expression profiles. In this project, we will use a custom breast cancer array that we developed to represent the genes most capable of differentiating breast cancers, and then use this array to analyze gene expression profiles in microdissected breast cancer samples. Groups of tumors that share expression profiles, identified through cluster analysis of data, will then be examined for pathological and clinical similarities to develop more specific hypotheses of ductal cancer classification. Finally, we will design case-control studies to test and refine these classification hypotheses. Through this stepwise development and testing of classification hypotheses, we expect to identify biologically distinctive categories of breast cancer. A sound molecular classification of this nature will greatly benefit clinical management of breast cancer patients and will provide a useful reference for the design of breast cancer research.
Project 2A - "Molecular Detection of Breast Cancer" Molecular methods hold promise for the detection of fewer numbers of cells than conventional histological examination. The molecular changes in cancer include epigenetic alterations, such as the abnormal methylation of promoter regions of CpG islands. Molecular techniques based on the sensitive detection of abnormal methylation now exist and hold promise as one such molecular method for detection of tumor cells. Breast cancer, like many other malignancies, has recently been shown to have abnormal methylation of many genes, including some tumor suppressor genes. These changes can then serve as the basis for a molecular detection strategy. The management of breast cancer patients can benefit from more accurate methods of determining risk of disease recurrence following surgical resection. While the majority of women with histologically negative lymph nodes will be cured by local therapy alone, approximately twenty-five to thirty percent of these patients will go on to recur and die of their disease within ten years of the time of diagnosis. A molecular means to more accurately predict recurrence in this group would be desirable. Early detection of breast cancer results in improvements in mortality from the detection of early, more readily curable disease. However, 10-15% of breast cancers are not detected by mammography. An improved method of detection might improve the survival of patients whose tumors are not detectable by mammography. The specific aims are: 1) To develop and optimize tumor specific DNA methylation changes as a molecular marker in breast cancer and validate this approach in the molecular staging of breast cancer. 2) To use the tissues obtained in a prospective ongoing trial of sentinel lymph node biopsy technology to subdivide the node negative group of patients into groups with differing prognoses based on molecular evidence of methylated alleles representing nodal metastasis. 3) To examine the feasibility and utility of the detection of methylated alleles in nipple aspirate fluids (NAF) and ductal lavage (DL) for the early detection of breast cancer.
Project 3A - "Novel Polyamine Analogues for Breast Cancer Treatment" The requirement of polyamines for neoplastic growth makes the polyamine metabolic pathway an attractive target for antineoplastic intervention. Recent advances in the design and testing of a new generation of polyamine analogues has improved the likelihood of discovering a breast tumor specific agent. In normal tissues, perturbation of polyamine metabolism generally leads to a decrease in growth rate but does not produce toxicity. However, through the use of the novel antineoplastic polyamine analogues instances of phenotype-specific cytotoxicity have been discovered in breast and other important human solid tumors. Although many new analogues have been synthesized, little work has been performed in the breast cancer systems. However, it was the breast cancer systems that first provided definitive evidence that the polyamine analogues killed cells through an induction of a programmed cell death pathway. Further, the induction of programmed cell death was found to result from both caspase-dependent and -independent pathways. A series of preliminary studies in breast cancer cell lines has demonstrated that many unsymmetrically substituted polyamine analogues are highly effective in growth inhibiting or killing breast tumor lines regardless of their estrogen receptor status or their resistance to other chemotherapeutic agents, including adriamycin. The studies detailed in the current proposal are designed to expand upon the above and other findings with the polyamine analogues and to continue to design and synthesize additional and potentially more efficacious antitumor agents. We will expand upon the finding that in some tumor systems the production of H202 as a by product of analogue induced polyamine catabolism is partly responsible for tumor-specific toxicity. Our recent discovery that some polyamine analogues induce a profound G2/M block resultant from interference with tubulin polymerization will be examined to determine what role this mechanism may play in those breast cancer that are sensitive to the polyamine analogues. Based on the novel activities of the polyamine analogues, combinations of classical antiproliferative agents with the new polyamine analogues will be examined for enhanced activity against a series of representative breast cancer lines with the goal of finding combinations which have significant clinical potential. Finally, when a sufficient number of analogues have been synthesized and tested, a systematic structure activity analysis will be performed to aid in the design of additional agents with the goal of improving upon effectiveness and selectivity against breast cancer. Finally, in collaboration with other members of this SPORE application, the possibility of combining the polyamine analogues with other modalities of breast cancer treatment, including immune modulation, will be examined.
Project 3B -
Inactivation of genes that regulate cell proliferation and death is a critical part of the neoplastic process. Crucial genes like tumor suppressor genes can be inactivated via gene deletion, point mutation, or inhibition of transcription. One mechanism for transcriptional inhibition is methylation of cytosine-rich areas, termed CpG islands, in the 5' regulatory region of the target genes. Methylation in these islands can directly inhibit transcription or stabilize structural changes in chromatin that do not allow transcription and can be modified through inhibition of the enzyme, DNA methyltransferase. The role of histone acetylation as a mechanism to alter chromatin structure and gene transcription has also been recognized. This is modified by the actions of histone acetyltransferases and deacetylases. As DNA methylation and histone acetylation are reversible processes and inhibitors for both exist, this proposal will investigate the possible strategy of inhibition of DNA methylation or histone deacetylation or both as methods to reexpress trancriptionally silent tumor suppressor genes in human breast cancer cells.
Project 3C - "Vaccines: A New Paradigm for Breast Cancer" Traditional therapies, including surgery, radiation, and chemotherapy, have played a significant role in the treatment of breast cancer. However, it is unlikely that these modalities alone can be further optimized to cure the 44,000 women/year who currently fail these modalities. Immunotherapy is another modality that has recently shown promise for the treatment of breast cancer. In particular, the Herceptin antibody that is specific for the HER-2/neu (neu) protein results in cancer regression in patients who are resistant to the other treatment modalities. Vaccines, a form of immunotherapy, have the advantage over other treatments in that they are specific, can amplify the response to meet the burden of existing cancer, and can induce immune memory for the cancer if it recurs. In addition, vaccines have the potential to induce immunity capable of preventing cancer development. A few vaccines have already resulted in cancer remissions for patients with small disease burdens. However, to date, the majority of vaccines have been developed using tumor cell lines that are transplanted into non-tolerized mice, a situation that is very different from the tolerance that occurs to naturally arising human tumors. In this proposal, we will test the hypothesis that combining immune modulating antibodies that alter the natural signaling patterns of key T cell regulatory molecules together with antigen-specific vaccination can enhance the potency of neu-targeted vaccines and result in improved treatment and prevention strategies. We will use the neu transgenic mice that naturally overexpress the neu protein and spontaneously develop mammary tumors. We have characterized these mice and found that they demonstrate neu-specific peripheral tolerance similar to what is observed in patients with breast cancer. Using this clinically relevant model, we have generated preliminary data demonstrating that neu-specific vaccine approaches can induces immunity potent enough to overcome peripheral tolerance and delay tumor development. In this proposal, we will: 1) Modify and optimize the most potent neu targeted vaccine; 2) Evaluate antagonist antibodies against CTLA-4, and agonist antibodies against CD40 and OX-40, three molecules that are critical for T cell activation and down-regulation, for their ability to enhance systemic antitumor immune responses; 3) Evaluate optimized vaccine plus immune modulating approaches that demonstrate improved antitumor activity in the less stringent transplantable tumor model for the ability to prevent spontaneous tumor development; 4) Evaluate optimized vaccine plus immune modulating approaches for the ability to overcome neu-specific peripheral tolerance under circumstances of large naturally developing tumor burdens. Although neu is the immune target in these studies, it serves as a model antigen for testing vaccine treatment and prevention strategies. The final goal of this proposal is to use information gained from these studies to design clinical trials aimed at both the treatment and prevention of breast cancer. The success of these studies may define a new paradigm for cancer prevention.
Project 4A - "Molecular Epidemiology of Progression to Breast Cancer"
We propose two complementary population-based studies to examine the contributions of serologic growth factors and polymorphisms in candidate genes controlling DNA repair, antioxidant defense, proliferative processes, and metabolism of hormones and xenobiotic compounds to the initiation of, and progression toward, breast cancer. Both studies will be conducted within an ongoing cohort study of 16,000 women participants of a population-based specimen bank (CLUE II) established in Washington County Maryland in 1989.
Core 1 - "Administration and Communication" The SPORE Administration and Communication Core will be responsible for managing the SPORE and disseminating information within the SPORE and for external interactions. The Core is designed for low-cost, yet efficient administration and communication in order to focus funds on research activities. The Core includes an organizational diagram for management activities. Monitoring of research will occur via: (1) Research Project Teams. (2) Research Project and Core Principal Investigators Committee and (3) SPORE Steering Committee. An Institutional Advisory Board and External Advisory Panel will provide yearly formal evaluations and reports to the Steering Committee. The communication component of the Core is directed at intra-SPORE, inter-SPORE, and National Cancer Institute research activities. Research communication is facilitated by online World Wide Web pages. The Core provides travel funds for Johns Hopkins Breast Cancer SPORE participation in the National Cancer Institute SPORE meetings to include the members of the Research Project and Core Principal Investigators Committee and SPORE Principal Investigator. In addition, communication of validated results to the medical community in order to have impact on incidence and mortality of breast cancer will occur via publication of SPORE findings in the medical literature; news releases to medical writers and press conferences for announcement of important advances with the assistance of the Office of Public Affairs of The Johns Hopkins Medical Institutions; and, when appropriate, alerts coordinated through the National Cancer Institute program staff. Interaction with lay advocacy groups and individuals will be facilitated through Cindy Geoghegan, a breast cancer advocate, who will serve as a member of the Steering Committee.
Core 2 - "Human Specimen Resource and Database" The Johns Hopkins Breast Human Specimen Resource and Database Core is an interdepart-mental collaborative effort designed to support multidisciplinary basic and translational research on the etiology, early detection, prevention and treatment of breast cancer and its precursors. The Core was designed using strategies that have proved successful in establishing tissue banks within the Department of Pathology and Core facilities for SPORE grants in gastrointestinal, prostate and pulmonary carcinoma at our institution. The Core provides flexible specimen collection techniques with quality assurance measures, inventory and tracking, collection of breast cancer risk factor information using a questionnaire based on validated instruments and a secure relational database for storing and retrieving data with back-up of files. Storage of frozen specimens, laboratory processing and data management will be performed in dedicated facilities located in the newly constructed Johns Hopkins Cancer Center in immediate proximity to the operating rooms, surgical pathology laboratory, and research laboratories. The Core is designed to collect frozen breast tissue and cells, blood components, nipple fluid aspirates and other biological specimens. The Core is directed by an experienced pathologist with expertise in breast and gynecologic pathology and molecular epidemiology and will be staffed by trained technical personnel who report to the Director. The Co-PI of the Core is an experienced surgical pathologist and molecular biologist who has a special interest in breast cancer. The Core is a prospective collection of data and specimens donated by patients who either present to Johns Hopkins for initial diagnostic evaluation or have been referred to Hopkins following a diagnosis at another institution. Patients are recruited through two possible mechanisms intended to maximize subject participation. In addition to the prospectively acquired collection described below, the Breast Center has access to retrospective collections of frozen and fixed breast specimens acquired at our institution and also has potential access to additional prospectively collected resources through collaborative agreements.
Core 3 - "Biostatistics and Bioinformatics" This core resource will provide biostatistical consultation and support to the projects in the program, by assisting in the design, collection, visualization, analysis, quantitative modeling, and interpretation of the result of project activities. In addition, it will provide bioinformatics consultation to the projects in the program, and assist with the identification and solution of complex data base tasks arising in the course of project activities.
List of Investigators involved in SPORE Projects
Robert A. Casero, Jr., Ph.D. |
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