PROJECT SUMMARY/ABSTRACT The current lack of effective, targeted cancer therapies reflects a gap in knowledge surrounding the mechanisms that promote tumorigenesis and emphasizes the need for new therapeutic approaches. For decades, genetic drivers were thought to be the sole mechanism that promote tumorigenesis. Recent advances have established epitranscriptomics, which details the regulatory and functional roles of RNA modifications, as an emerging mechanism of tumorigenesis and potential therapeutic avenue. N6- methyladenosine (m6A) is the most prevalent modification on messenger RNA (mRNA) and serves key roles in gene regulation and expression. However, our understanding of how mRNA m6A methylation contributes to tumorigenesis is limited and warrants further investigation. The F99 phase of my proposal will determine the novel role of ALKBH1, a member of the AlkB family of Fe2+/𝛼𝛼-ketoglutarate-dependent dioxygenases, in regulating mRNA m6A methylation in arsenic-induced skin tumorigenicity. Chronic exposure to inorganic arsenic through contaminated drinking water is a major carcinogenic driver of skin cancer. However, the mechanisms that underlie arsenic-induced skin tumorigenicity remain poorly understood and few therapeutic targets have been identified. I hypothesize that ALKBH1 promotes arsenic-induced skin tumorigenesis by demethylating m6A on mRNA and regulating gene expression post-transcriptionally. The F99 phase of this proposal will address critical gaps in knowledge surrounding the molecular mechanisms that underlie arsenic- induced skin tumorigenicity and establish ALKBH1 and/or its targets as therapeutic targets for arsenic-induced skin cancer. The K00 phase will address a broader question and profile the dynamic role of m6A methylation in malignant transformation. Malignant transformation is a dynamic process. However, our understanding of the mechanisms that drive malignant transformation is limited to static comparisons across non-transformed and transformed cells and the transitional states that mediate the transformation between these cell types remain uncharacterized. The K00 phase will address this gap in knowledge by using m6A-sequencing to longitudinally profile the m6A-dependent epitranscriptome using validated models of in vitro transformation across a panel of carcinomas. I hypothesize that the m6A-dependent epitranscriptome changes dynamically throughout malignant transformation and that I will identify novel m6A-dependent targets that will increase our understanding of the processes that underlie the transformation from a normal cell to a tumorigenic cell. Successful completion of the F99 and K00 phases of this proposal will establish novel mechanisms of m6A regulation and function and identify new therapeutic targets and potential biomarkers of cancer development. My ultimate career goal is to become an independent investigator and run an interdisciplinary lab conducting NIH-funded work that investigates the interpl...