PROJECT SUMMARY Melanoma is the most aggressive form of skin cancer with rising incidence. Despite significant advances, available therapies are effective only in distinct subsets of patients where relapse, treatment-refractory disease, and/or significant toxicities commonly occur. It has become increasingly evident that epigenetic alterations that lead to aberrant gene expression programs play an integral role in melanoma initiation and development. Repressor Element-1 (RE-1) Silencing Transcription (REST), a zinc finger transcription factor (TF), has been implicated in a diverse subset of cancers as pro-proliferative in neural tumors and anti-proliferative in non-neural tumors. REST binds DNA in a sequence-specific manner at RE1 motifs and primarily functions to repress neuronal gene transcription in non-neuronal cells. REST-mediated gene repression is achieved by the recruitment of several chromatin modifying complexes to DNA that erase active histone marks and write repressive marks. Relevant to my proposal, TCGA data indicates that REST is overexpressed in metastatic melanoma compared to primary melanoma. Yet to date, there are no studies that have explored REST in regulating aberrant gene expression programs in melanoma. I found that REST loss-of-function impairs melanoma proliferation by inducing cell cycle arrest and subsequent apoptosis. RNA-sequencing analysis upon REST knockdown revealed that REST regulates key melanoma survival genes, enriched in pathways related to Cadherin, p38, and Wnt Signaling. Together, my phenotypic and transcriptomic analysis of REST depletion demonstrated, for the first time, that melanoma cells are dependent on REST. In this proposal, I seek to continue to test my hypothesis that through the modulation of the epigenetic landscape, REST regulates pro-tumorigenic transcriptional programs in melanoma, utilizing a combination of functional and genomic approaches. I expect my findings to open avenues for investigation into the molecular mechanisms and cellular functions of REST and ultimately, to present a novel therapeutic strategy for melanoma patients.