The major cause of death in uveal melanoma patients is the spread or metastasis of the cancer to other vital organs such as the liver. Although most patients do not show signs of metastasis at the time of diagnosis, eventually about 50% of patients will develop metastatic disease, which is almost invariably fatal. Recently, it has been shown that about 80% of uveal melanomas possess a mutation in one of two similar Gaq genes, known as GNAQ and GNA11. These mutations are known to drive the formation and growth of the tumors. We have recently shown that the activation of a particular protein known as ARF6 by these mutations controls all of the known signaling pathways that are involved in cancer formation and growth. However, the genes that control the spread of the cancer to other parts of the body are not known for either the cancers with these more common Gaq mutations or for the remaining 20% of uveal melanomas that do not have mutations in the Gaq genes. Given that metastasis of the cancer is the primary cause of death, it is very important to identify the molecular basis for this process. In an earlier study, we showed that activation of ARF6 also controlled the metastasis of cutaneous melanoma. Our preliminary data for the present study suggest that activation of ARF6 by the binding of WNT5A to the cell surface receptor ROR2 enhances the molecular signaling pathways downstream of ROR2 and that ARF6 accomplishes this role by helping to move ROR2 from the cell surface to the inside of the cell. We have preliminary data suggesting that ARF6 not only promotes the internalization of ROR2 but also its localization to the nucleus of the cell where it functions in unknown ways possibly to promote uveal melanoma metastasis. Although we have preliminary data for all of these ARF6 functions, we need to confirm these results and try to better understand the mechanisms that govern these functions. Our experiments are designed to establish the role of ARF6 in uveal melanoma metastasis and begin to tease apart the mechanism underlying them. During the course of these experiments, we will be testing the function of ARF6 by reducing its expression levels and by inhibiting its activation using a small molecule compound that directly targets ARF6. If our experiments are successful and we show that ARF6 plays a critical role in uveal melanoma metastasis, we will have not only identified a novel molecule that could be targeted to reduce metastasis, but we will have generated a proof of concept for future drug development by showing the efficacy of inhibiting ARF6 activation using a small molecule compound. Such a compound could be used as a template for development of even more potent and specific compounds that could become drugs for the treatment or prevention of uveal melanoma metastatic disease.