KDM6A function in epithelial-mesenchymal plasticity

Baylor University, Waco TX

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Abstract

Cellular plasticity, including epithelial and mesenchymal transition (EMT), whether partial (pEMT), complete (cEMT) or reversed (MET) is critical throughout development and implicated in wound healing, cancer metastasis, and fibrotic disorders. The reversibility or irreversibility of EMT is critical to successful implementation of these cellular programs yet is not well understood. We have shown that EMT results in diminished expression and altered localization of the histone demethylase, KDM6A. KDM6A has been well characterized as a demethylase capable of removing H3K27me3 from the chromatin leading to loss of silencing at target genes. Moreover, we and others have shown that KDM6A loss is sufficient to induce partial EMT. However, how changes in KDM6A expression and nuclear localization affect the distribution of H3K27me3 during reversible or irreversible EMT is unknown. Moreover, many factors initially characterized as histone-targeting enzymes have additional protein targets throughout the cell. We have observed that KDM6A is not strictly localized to the nucleus but can also be localized to the Golgi body. Whether KDM6A targets non-histone proteins for demethylation is unknown. To achieve our long-term goal which is to understand the epigenomic impacts on epithelial-mesenchymal plasticity and elucidate associated mechanistic underpinnings, we propose to test the hypothesis that changes in KDM6A protein expression and localization facilitate epithelial-mesenchymal plasticity. Moreover, we will elucidate the mechanisms driving KDM6A suppression and sub-cellular localization. Completion of this work will lead to innovative concepts in the contribution of KDM6A to the intrinsic ability of a cell to reverse EMT and establish mechanisms used by cells to control KDM6A expression and localization. We will also identify novel targets of KDM6A, expanding our understanding of the function of this enzyme. The outcomes of this basic research will be relevant to diverse groups of biomedical scientists as epithelial- mesenchymal plasticity is a critical driver in various disease states which may be amenable to chromatin-targeted interventions. Furthermore, this work provides opportunities for undergraduate students to perform interdisciplinary research in cellular biology and analytical chemistry, while addressing fundamental questions in the biology of lysine demethylases and cellular plasticity. To facilitate enhanced determination of epithelial-mesenchymal phenotypic plasticity we propose to acquire and utilize a dual fluorescent, in-incubator, live cell imaging instrument. This technology will enhance the reproducibility of our approach and reduce bias in image acquisition and interpretation. Additionally, this technology will facilitate novel approaches using 3D culture and cultured organoids. Together use of a live cell imager will increase the rigor, reproducibility and impact of the ongoing studies.