Project Summary The goals of this Pathway to Independence Career Development proposal are to request support for training to develop expertise in cancer epigenetics while addressing the role of slow cycling cells and histone modifications in phenotype plasticity of highly resistant metastatic melanoma. K99/R00 support during this part of my career will be integral to my successful development as an independent cancer researcher. The training plan outlined in this proposal will take advantage of the extensive resources at The Wistar Institute, University of Pennsylvania as well as Temple University. My training will also be guided by senior personnel who have successfully mentored predoctoral, postdoctoral, and clinical fellows in academic careers. The scientific portion of this proposal focuses on experimentally determining the molecular mechanism underlying phenotype plasticity and therapy resistance of invasive melanoma and the role of epigenetic changes in phenotype plasticity and maintenance of slow cycling cells. The proposed studies are based on my previous findings that a subset of melanoma cells, which express Wnt5A and p21, survive multiple types of stress by entering a slow-cycling, senescent-like state, but still invade and retain the ability to form metastases. My preliminary data suggest SEDTB1 expression correlates with an invasive phenotype in our human melanoma cell lines and driving non-invasive melanoma cells to a more invasive phenotype, through over expression of Wnt5A, increases SETDB1 expression. Expression of SETDB1, a histone methyltransferase, has been implicated in the silencing of tumor suppressor p16. p16 is expressed in melanocytes and early stages of melanoma but is lost during melanoma progression and this correlates with p21 expression and a senescent-like response following stress. In melanoma, hypermethylation during tumor progression is observed, which may block the expression of multiple tumor suppressor genes, but the role of specific epigenetic changes in phenotype plasticity and drug resistance is still largely unknown. Therefore, in line with these data I will explore the following scientific aims: 1) to elucidate the mechanism by which Wnt5A and p21 promote the maintenance of slow cycling stem-like cells;; and 2) to determine if histone modifications induced by SETDB1 promote phenotype plasticity and invasion in melanoma cells. The completion of the scientific aims in this proposal will develop my research skills and knowledge in cancer epigenetics while delineating the mechanism by which highly invasive resistant cells evade stress to promote melanoma metastasis and therapy resistance.