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Johns Hopkins Lung Cancer SPOREStephen B. Baylin, M.D.
PROJECT 1: EPIGENETIC STAGING AND THERAPY FOR LUNG CANCERCo-Lab PI: James Herman, M.D. Our SPORE has been instrumental in establishing that promoter region DNA hypermethylation, and attendant abnormal gene silencing, play a key role in the development and progression of human cancer, in general, and lung cancer, in particular. During the past funding cycle, we markedly moved this concept to a highly translational arena in terms of lung cancer management through a synthesis of studies. These include discovery of new genes aberrantly methylated in lung cancer and defining their position and biological function in the progression of the disease. Most importantly, we now have defined the utility of a panel of promoter region DNA methylation markers as a robust potential molecular system for re-staging stage I NSCLC to stage III disease. During the last funding period, we performed a blinded, retrospective, nested case control study of 167 patients who underwent curative surgery for stage I lung cancer (51 cases who recurred within 40 months; 116 controls who did not recur). The finding that 2 or more DNA hypermethylated genes in tumor plus histologically tumor-free mediastinal nodes can predict recurrent disease with odds ratios up to 25-fold, constitutes a new paradigm for the molecular staging of lung cancer. The significance of these discoveries has important implications which will be explored in the current proposal. Silencing of the gene markers represent not only prognostic markers, but also serve as a potential target for a unique new adjuvant approach for stage I non-small cell lung cancer (NSCLC) using epigenetic therapy to re-express the silenced genes. To prepare for this, we have started a prospective study of resected stage I lung NSCLC to validate our above work indicating that changes in DNA methylation can predict disease recurrence and death. We will also use newly discovered changes in promoter methylation to improve this molecular test. To prepare for use of epigenetic therapy adjuvant approaches, we will continue an already initiated Phase 2 trial of epigenetic therapy with inhibitors of DNA methylation and histone deacetylases, in which a major response has already been achieved. Finally we will initiate an adjuvant trial with these agents, to determine if targeting epigenetic changes improves the disease free and overall survival of patients with resected lung cancer. Successes, here will suggest prevention strategies as well. Relevance to Public Health: Lung Cancer is responsible for the greatest number of cancer deaths in the United States and other western countries. Effective treatment of early stage lung cancer would result in improvements in survival and reduction in death from lung cancer. Our studies should help define which patients with early lung cancer are at highest risk for disease recurrence after surgery, and therefore need additional therapy. In addition, we will determine whether therapy directed at these changes proves effective in reducing disease recurrence.
PROJECT 2: GENE PROMOTER HYPERMETHYLATION AS A BIOMARKER FOR LUNG CANCER DETECTIONCo-Lab PI: Steven Belinsky, Ph.D. Mortality from lung cancer could be reduced substantially through early detection and the implementation of targeted approaches for chemoprevention and treatment of early stage cancers. We conducted the first study in collaboration with the Colorado Lung SPORE to prospectively evaluate methylation in sputum of a large panel of genes for their ability to predict lung cancer. This nested, case-control study of persons from the Colorado Cohort revealed that a panel of genes could predict incident lung cancer between 3 and 18 months prior to clinical diagnosis with both a sensitivity and specificity of 64%. This same marker panel is now being used to evaluate methylation in sputum from prevalent stage I lung cancer cases compared to a second cohort of high-risk smokers. Methylation of three or more genes of a seven-gene panel revealed a sensitivity of 75% and a specificity of 81%. Evaluation of additional candidate biomarkers has identified other promising genes for inclusion in the ultimate panel for early detection of lung cancer. These studies support advancing a methylation gene panel to full clinical validation as a tool for early detection. This will be accomplished through collaboration with the Colorado SPORE by first determining the optimal gene panel for distinguishing newly diagnosed stage I lung cancer from cancer-free smokers. We will then validate the performance of the ultimate gene panel for early detection of lung cancer using ACRIN, a prospective cohort of people at high risk for lung cancer within the National Lung Screening Trial who are randomized to lung cancer screening modalities. Through a nested, case-control design, the sensitivity, specificity, positive, and negative predictive values of this gene panel will be determined. A second major goal for this project is to collaborate closely with Project 1 in which the reversal of abnormal gene silencing is being tested as a therapeutic target for lung cancer. The strategy of using the demethylating agent 5-azacytidine and the histone deacetylase inhibitors, sodium phenylbutyrate or MS275 has shown promising responses in the treatment of myeloid malignancies. This therapy may also be effective in an adjuvant setting to prevent recurrence of cancer in resected stage I lung cancer patients. Through collaboration with Project 1, we will use gene methylation in sputum as a biomarker to predict therapeutic response and recurrence of lung cancer in resected stage I lung cancer patients receiving adjuvant treatment with demethylating agents. Relevance to Public Health: These studies should ultimately lead to the development of an approved diagnostic test for early detection of lung cancer. In addition, these studies should clearly impact how early stage lung cancer is managed by creating a molecular-based test to guide treatment decisions and provide biomarkers for monitoring the efficacy of demethylation therapy.
PROJECT 3: DEREGULATED NRF2-KEAP1 PATHWAY AS A CRITICAL REGULATOR OF CHEMORESISTANCE IN LUNG CANCERCo-Lab PI: Shyam Biswal, Ph.D. Chemoresistance remains the greatest challenge in improving survival of lung cancer patients. Lung cancer cells have greater expression than normal cells of proteins involved in detoxification of electrophiles and drugs detoxification and efflux pumps [Glutathione and Thioredoxin system and Multidrug resistance proteins] that provides intrinsic resistance against chemotherapy. Studies in project 3 have established that activation of the redox-sensitive transcription factor, Nuclear factor erythroid-2 related factor 2 (NRF2), in response to xenobiotic stress, positively regulates the expression of electrophile, xenobiotic detoxification enzymes and efflux pumps which confer cytoprotection against oxidative stress and apoptosis in normal cells. Kelch-like ECH-associated protein (KEAP1) negatively regulates NRF2 activity by targeting it for proteasomal degradation. Increasing NRF2 activity by small molecule activators might protect the lung epithelium of high risk subjects from oncogenic damage due to carcinogens. However, a surprising finding has emerged in the project that provoked re-thinking about the NRF2 pathway in terms of lung and other cancers. We have recently discovered that dysfunctional KEAP1 activity is a frequent alteration in lung adenocarcinomas which results in greater nuclear accumulation of NRF2 and enhances the transcriptional induction of electrophile, drug detoxification, and efflux proteins. Thus, unlike normal cells, lung cancer cells have unrestrained high NRF2 activity leading to therapeutic resistance. KEAP1 in the adenocarcinomas has deletions, insertions, and missense mutations in functionally important domains of the protein, and a very high percentage of loss of heterozygosity at 19p13.2, suggesting that biallelic inactivation of KEAP1 in these cancers is a common event. Mutations were detected in all stages of adenocarcinomas (including stage IA). Decreased KEAP1 activity, in-vitro, causes radio- and chemoresistance. We have also identified mutations in KEAP1 in prostate tumors and recently similar mutations were reported in breast tumors.The new aims of this proposal are: Specific Aim 1: To determine the association between high NRF2 activity and chemoresistance in non-squamous non-small cell lung cancer (NSCLC); Specific Aim 2: To determine whether targeted NRF2 inhibition can diminish chemoresistance in preclinical models; and Specific Aim 3: To determine whether pharmacologically decreasing NRF2 activity in lung cancer can reverse chemoresistance. Relevance to Public Health: The studies in this project have potential for both identifying biomarkers to predict drug sensitivity in patients with lung adenocarcinomas and to devise new means to reverse chemoresistance in patients with drug-resistant tumors.
PROJECT 4: INHIBITION OF FATTY ACID SYNTHASE FOR LUNG CANCER TREATMENTLab PI: Ed Gabrielson, M.D. This project will continue studies on the use of pharmacological inhibitors of fatty acid synthase (FAS) for lung cancer treatment in both the setting of clinical trials (with correlative markers) and in the laboratory setting for refinement of this treatment strategy. Under current funding from the SPORE mechanism, we have 1) confirmed that FAS is a promising target for lung cancer treatment, 2) identified a class of pharmacological compounds that can selectively inhibit FAS activity without significantly affecting fatty acid oxidation (with associated anorexia), and 3) demonstrated that these compounds effectively inhibit growth of human lung cancer xenografts and mouse lung tumors, without causing significant toxicity. Furthermore, our work has evaluated pharmacokinetics of a FAS inhibitor and demonstrated the ability to administer these compounds orally, which support our expectations of moving this project to clinical trials for lung cancer treatment. Finally, experiments conducted during the initial funding period have demonstrated the ability of positron emission tomography (PET) imaging to monitor response to FAS inhibitors, and also found additive or synergistic effects when FAS inhibitors are used in combination with other chemotherapeutic agents. In the first specific aim of this proposed project, we will evaluate a pharmacological inhibitor of fatty acid synthase in early stage clinical trials. We expect to initiate a phase 1 trial in the current funding period, and phase 2 clinical trails in the proposed funding period. Both phase 1 and phase 2 clinical trials will include monitoring patients with the candidate markers of response developed in Specific Aim #2 (including FDG/PET imaging), in addition to standard measures of patient response. Specific aim #2 will determine the effect of fatty acid synthase inhibitors on signal transduction pathways and cellular metabolism in pre-clinical models of lung cancer, to identify potential markers for predicting and monitoring response to these agents. As noted above, these markers will be applied to the clinical trial setting. Finally, in specific aim #3, we will evaluate the potential role for fatty acid synthase inhibitors in combination cancer therapy. We will evaluate potential additive or synergistic effects of combining FAS-inhibiting compounds with conventional chemotherapeutic agents for lung cancer, as well as with novel agents that target specific signal transduction pathways. Understanding how a FAS inhibitor can be effectively combined with other agents will provide a framework for effective use of this compound in the clinical setting. Relevance to Public Health: This project will develop a new therapeutic strategy for lung cancer treatment.
CORE A: ADMINISTRATIVEStephen B. Baylin, M.D. This core is responsible for enabling the PI to manage all the parameters of the SPORE. It is designed to accomplish this with low-cost, yet efficient administration and communication in order to divert as little funds as possible from research activities. The administrative component of the Core facilitates all communications necessary to initiate and foster SPORE activity including: 1) arranging all presentations to our internal and external review committees; 2) travel arrangements for the external committee and arranging of all meeting schedules, etc; 3) notification of national SPORE activities to all SPORE members including arrangements for attendance to the national meeting and abstract requests, etc.; 4) arranging all local SPORE meetings including attendance of our advisory committee; 5) arranging all conference calls between the NCI, the other SPORES, and our SPORE for design of the consortium prevention trials, design of the national meeting, design of national lung cancer SPORE meetings; 6) preparation of all grants including yearly progress reports and budget preparation, competitive renewals and budget preparation, etc.; and 7) management of budgets during each funding period including tracking expenditures, managing subcontracts to SPORE projects at institutions outside Hopkins, etc.
CORE B: HUMAN TISSUE AND PATHOLOGYPI: Ed Gabrielson, M.D. The Pathology and Tissue Core of the Johns Hopkins Lung SPORE program was initiated approximately 14 years ago. The Core activities have evolved over this time period. While the initial emphasis of the Core was to collect frozen tissue samples, services added in response to evolving need of the SPORE include tissue microdissection, collection of specialized samples (lymph nodes, bronchiolaveolar lavage, sputum), expanded data collection and management services, establishing tissue microarrays (TMAs), and pathology consultation for use of human specimens as well as animal models. In addition, the Core has supported the continuous development and refinement of a relational database that provides comprehensive clinical data for all lung cancer patients at the institution in addition to annotation for the pathology specimens in the Core. All of the resources of this Core are leveraged beyond our own SPORE program, as we continue to have active collaborative efforts with investigators at other institutions, including investigators in other SPORE programs. In the past two years, investigators in our program have recognized a need for laboratory models that resemble human lung cancer more closely that do the standard cultured lung cancer cell lines. This prompted the development of a new resource in the Core for establishing transplantable xenografts from clinical samples of human lung cancers. We expect that this resource will contribute significantly to work of investigators throughout the lung cancer research community in coming years, as well as to the projects of our SPORE. Thus, the basic functions of this Core can be summarized as follows:
Relevance to Public Health: This Core provides valuable resources to link laboratory studies to clinical applications.
CORE C: STATISTICALSteven N. Goodman, M.D., MHS, Ph.D. The Biostatistics core of the proposed Johns Hopkins SPORE in lung cancer will consist of experienced faculty and of the Division of Biostatistics and Research Information Technology in the JHU Oncology Center, augmented by a faculty-level long term statistical collaborator of Dr. Belinsky in Colorado. A long history of collaboration already exists between the Oncology Biostatistics personnel and investigators on this SPORE. Its purpose is to
The Core will have an integral role in the scientific development, execution, and analysis of all projects in the SPORE. Core investigators have extensive and complementary experiences in quantitative methods for biomedical applications, including both clinical and basic science studies. They take a direct interest in the substantive issues being investigated; to participating in regular project and program meetings, and to providing rigorous and innovative input on all quantitative matters arising in the projects. By contributing to multiple projects, they will also be in a position to promote interdisciplinary interactions among projects. This resource will also provide any needed bioinformatics consultation to projects in the program if they should arise, because a strong resource exists within the biostatistics program by virtue of its role in other SPORE programs. |
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