The proposed training grant will facilitate the improvement of the education and career goals of the principal investigator (PI) as well as will lead to important findings in the field of cancer epigenetics with the aim to increase the therapeutic potential in T cell leukemia. Up to 25% of children with acute lymphoblastic leukemia (ALL) will fail frontline therapy and their prognosis is dismal with only 20% cure rate. Although prognosis is better for patients with later relapses, the majority eventually succumbs to the disease (overall cure rate 40 to 50%). Usually, central nervous system (CNS) involvement, lower remission and re-induction rates and early second relapse for those who enter remission are important obstacles in the way to treatment whereas more aggressive types of therapy, including bone marrow transplantation, reached tolerability limits with toxic death rates generally ranging from 3-19%. Also direct inhibition of Notch pathway in T cell ALL (T-ALL) has been plagued by gastrointestinal toxicity. The hypothesis of this proposal is that epigenetic drugs can be used as a targeted therapy against acute lymphoblastic leukemia, especially when classic chemotherapy and/or irradiation have failed. Using mouse models and primary human samples, we recently identified inactivating genetic alterations of members of the polycomb repressive complex 2 (PRC2) in T-ALL and revealed the importance of the levels of the repressive mark trimethylation of histone 3 lysine 27 (H3K27me3) in leukemogenesis. We have also generated strong data on the prominent but contrasting roles of two H3K27me3 demethylases JUMONJI D3 (JMJD3 or KDM6B) and UTX (or KDM6A) in the same disease. JMJD3 is a facilitator of the oncogenic process whereas UTX is a tumor suppressor although they execute the same enzymatic action. Using a specific chemical inhibitor we were able to kill T cell leukemia, sparing myeloid leukemia and physiological cells. Moreover we have identified that the family of metabolic genes succinate dehydrogenase (SDH) is transcriptional target of UTX. As these genes have been shown to play tumor suppressor roles in tumors of endocrine origin, we hypothesize, based on strong preliminary results, that a part of UTX action is filtered through SDH family. In the K99 phase of this proposal we aim to: 1) Identify and characterize the oncogenic topological domains (TD) containing NOTCH1 and JMJD3 in leukemia, 2) associate specific TD with disease progression (prognostic model), 3) identify interacting partners for UTX, 4) understand the molecular and physiological roles of SDH in T cell leukemia and 5) to generate and perform basic phenotypic analysis of two animals (mice) modeling mutations of UTX in human disease. During the execution of the K99 phase of this project, the PI will acquire technical skills on chromosome conformation capture techniques, fluorescent In situ hybridization (FISH) and basic metabolic analysis and he will also improve his knowledge on basic bioinformatics (high-throughput data) analysis. In the R00 phase, the candidate will use the skills and tools produced during the K99 phase, use the GSKJ4 inhibitor against demethylases in samples from diagnosis/relapse disease and associate changes with expression and phenotypic changes in the sample as a proof-of-principle for the model interactions. Moreover the PI will fully analyze the tumor suppressor role of UTX through genetic, metabolic, biochemical and epigenetic studies of the generated mouse models. In summary we will set up chromatin models for testing of current drugs and explore metabolic pathways with the perspective to understand the connection between metabolism and epigenetics in cancer and discover new therapeutic targets in the future. We believe that these findings can be applied to other types of cancer, as the mechanisms we explore are universal. The PI has brought together an extensive panel of experienced collaborators and his mentor. This plan includes also regular meetings with members of his advisory board, courses on bioinformatics, networking, grant writing and responsible conduct of research as well as conferences on the aforementioned disciplines (tumor metabolism, genetic models of cancer) so he conveys his ideas and set up collaborations. Overall, the K99 award together with the mentor's and collaborator's experience and the advanced environment of Langone Medical Center at New York University will provide the PI with innovative tools to continue his independent career on the crosstalk between epigenetics and metabolism in leukemia.
T cell acute lymphoblastic leukemia (T-ALL) represents about 15% of pediatric and 25% of adult ALL and it is classified as high-risk type of ALL. This devastating pediatric blood cancer is represented with increased peripheral white blood cell counts, respiratory distress due to accumulation of mediastinal masses and increased risk of central nervous system involvement. Up to 25% of children with ALL will fail frontline therapy and their prognosis is dismal with only 20% cure rate. The main current therapies are based on chemotherapy or irradiation with severe side effects. The goal of current research is to design specific drugs to block tumor-initiating oncogenes. In this proposal we aim to target the essential oncogenic action based on pharmacological inhibition of the action of oncogenic epigenetic modifiers essential only for leukemic and not physiological cells. Finally we suggest delineating the mode of action of a typical epigenetic tumor suppressor using mouse models of leukemia. This proposal will lend rational to the use of drugs targeting chromatin components as a synthetic lethality approach.
|Ntziachristos, Panagiotis; Tsirigos, Aristotelis; Welstead, G Grant et al. (2014) Contrasting roles of histone 3 lysine 27 demethylases in acute lymphoblastic leukaemia. Nature 514:513-7|
|Di Micco, Raffaella; Fontanals-Cirera, Barbara; Low, Vivien et al. (2014) Control of embryonic stem cell identity by BRD4-dependent transcriptional elongation of super-enhancer-associated pluripotency genes. Cell Rep 9:234-47|