The treatment of primary brain tumors poses a particularly formidable challenge in the field of oncology given its aggressive course and resistance to conventional therapies. To effectively generate paradigm-shifting therapeutic approaches against brain tumors, a rapid translation of high impact laboratory research findings into well constructed clinical trials is needed. As a mid-career physician scientist and researcher, I have successfully conducted basic research in the laboratory providing insights into biology of brain tumors and seamlessly moved these ideas into clinical trials against brain tumors; This has been possible due to my training in basic research and experience in clinical care in both neurology and neuro-oncology, which allow me to specifically conduct patient-oriented research related to neurological malignancies. In addition, I have taken a proactive role in mentoring neuro-oncology fellows as the former director of Neuro-oncology fellowship program. My current role as director of Clinical Research provides me with the unique opportunity to combine patient oriented research with focused mentoring. The K24 grant will provide protected time and resources to expand my clinical research efforts into epigenetics of brain tumors, which has emerged as a new area of interest based on my laboratory studies. Epigenetics pertains to the changes in gene expression not due to change in the DNA but due to alterations of control mechanisms that regulate the structure and access to chromatin. In disease processes such as cancer, epigenetic changes can dramatically influence tumor biology, response to therapy and prediction of outcome; one such effect, MGMT promoter methylation, is already known to influence the outcome of glioblastoma (GBM), the most aggressive of primary brain tumors. Recently, bevacizumab, a humanized antibody that blocks vascular endothelial growth factor (VEGF) and prevents neoangiogenesis has shown efficacy against recurrent GBM and is approved for this indication. Although initially effective, tumors adapt to VEGF inhibition and bypass this blockade through several mechanisms leading to recurrence. Epigenetic factors leading to altered gene expression have been shown to reverse this resistance in preclinical studies by inhibiting the escape routes including non-VEGF molecular pathways such as overexpression of HIF1, PDGF and IGF as well as recruitment of circulating endothelial cells. The short term goal of this project is to conduct a clinical trial to test the hypothesis that vorinostat, which epigenetically changes DNA structure, can prevent the development of resistance to bevacizumab in patients with recurrent glioblastoma and significantly delay tumor recurrence and improve survival. This trial is unique in that a new statistical design based on Bayesian adaptive randomization methods will allow us to compare the combination of bevacizumab and vorinostat with bevacizumab alone in an efficient pick the winner design. The study is also designed to include DCE/DSC MR imaging to measure changes in perfusion and diffusion within the tumor as a noninvasive marker of treatment outcome. It also includes serum biomarker measurements to determine their association with outcome. The study will provide both new insights into overcoming resistance to antiangiogenic agents and test novel trial designs; it will also provide me with an excellent opportunity for mentorship of fellows and junior faculty in the conduct of trial design and rational targeting of gliomas. Mentoring fellows and junior faculty is one of my major goals under this grant and I will actively involve neuro-oncology fellows in the various projects involving epigenetic laboratory research and clinical trials; my efforts will also be specifically directed towards guidance of junior faculy in their own projects with a goal to move them to an independent academic path. The long term goal of this project is to develop a comprehensive strategy towards a Brain Tumor Epigenetics Program within the Brain Tumor Center that will support studies of epigenetic factors influencing tumor biology in various areas of research and training and consequently develop novel approaches to brain tumor therapy.
Primary brain tumors are among the worst in prognosis among human malignancies. Efficient development of novel therapies against primary malignant gliomas require rapid translation of results from promising laboratory studies to well designed clinical trials; this will allow rapid screening of new therapies in order to channel the most promising of these to large confirmatory trials. This Mid-Career Investigator grant will allow Dr. Puduvalli, the principal investigator of this project, to design and deploy novel therapeutic strategies that targets 'epigenetics' of brain tumors, which is essential for regulation of the tumors biological processes and treatment response; in addition, it will allow Dr. Puduvalli to develop a new program in brain tumor epigenetics and provide opportunities for mentorship of neuro-oncology fellows and junior faculty.
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