Targeted Therapies in Melanoma

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DESCRIPTION (provided by applicant): The long-term objective of this program project is to develop new strategies for the treatment of melanoma, based on a mechanistic understanding of key proteins that are associated with the disease and the development of small molecule inhibitors to these proteins. The group proposes to pursue the following goals 1. Target oncogenic BRAF for therapy of melanoma. The oncogenic BRAF mutant, BRAFV600E, has evolved as, arguably, the most important target in melanoma. We will use several approaches to explore the use of BRAF , as a target for therapy: We will: i. Use currently available inhibitors of the MARK pathways with activity for either BRAF or MEK using complex in vitro and orthotopic in vivo models (Project 1); ii. Induce specific cellular immunity against BRAF that leads to tumor growth inhibition in a melanoma model in mice (Project 2); iii. Develop a new generation of inhibitors for BRAFV600E based on the crystal structure of BRAF (Project 3); and iv. Develop new organic inhibitors and a new generation of organometallic inhibitors using a ruthenium pyridocarbazole molecular scaffold to BRAFV600E with increased specificity and efficacy (Projects 3 and 4). We expect the development of new therapies of melanoma that focus on BRAFV600E as a molecular target to result from these combined biological, immunological, structural and chemical studies. 2. Target the PI3 kinase pathway with a new generation of inhibitors and use these in combination with BRAF inhibitors for therapy of melanoma. Based on preliminary studies in project 1, we hypothesize that PI3a kinase pathways are highly important for melanoma cell survival. Projects 3 and 4 combine structural and chemical strategies to identify a novel generation of inhibitors to the PI3Ka/? isoforms. The inhibitors will be developed based on the organometallic scaffold described above for the BRAF kinases (Project 4), and supported by inhibitor screens in vitro (Project 4) and in vivo (Projects 1) and x-ray crystal structures of PI3K? inhibitor complexes (Project 3). In addition, we will explore novel Akt/PKB inhibitors using in vitro and in vivo models and investigate how they synergize with BRAF inhibitors (Projects 1 and 2). 3. Target GSK3? for induction of apoptosis. We have found that targeting GSK3? with organometallic inhibitors (developed in Project 4) has surprising apoptosis-inducing activities on melanoma cells (Project 1). Based on these preliminary studies we will now investigate the mechanisms of apoptosis induction, which may occur through activation of p53 (Project 1). We will also continue to prepare more potent and specific organometallic GSK3? inhibitors in project 4 for treatment of melanoma cells in project 1. Most melanomas are not mutated in GSK3?, but p53 can also be downregulated by HDM2, which is frequently overexpressed in melanoma. Together, the collaborations among members of the Program Project will combine expertise in tumor biology, tumor immunology, biochemistry, chemistry and structural biology to generate unique approaches and reagents for use in melanoma therapy.