Identifying the Novel Effectors of Oncogenic GNAQ/11 and BAP1-Deficiency in Uveal Melanoma

Uveal melanoma is a deadly form of eye cancer arising from melanocytes of the uveal tract. In North America and Europe, the incidence of uveal melanoma is every 5-8 adults per million individuals. Many advances have been made in successfully treating primary uveal melanoma.; however, 50% of patients eventually develop distant metastases regardless of primary treatment outcomes. Molecular, genetic, and cytogenic characterization of uveal melanoma in the past decade has significantly enhanced the ability to identify patients at high risk of developing metastasis. The mutational landscape has been clearly laid out with primary driver and metastatic potential mutations identified. However, the process of metastasis is incompletely understood, and there is an urgent unmet need to find targeted therapies for uveal melanoma.BAP1-deficiency accounts for the majority of metastatic patients, but its exact function in uveal melanoma metastasis is unknown. Prior studies investigating metastasis have focused on the process of epithelial-mesenchymal transition (EMT) and loss of adhesion molecules. Here we show that BAP1-deficiency is associated with the upregulation of cell adhesion molecules such as E-cadherin and CADM1. Knockdown of E-cadherin demonstrates a loss of cluster formation, while knockdown of CADM1 reduces cell viability in a matrix-detached environment in BAP1-deficient uveal melanoma cells. Cluster formation and matrix-detached survival are potential mechanisms BAP1-deficient uveal melanoma cells may be using to adapt to the metastatic process.Once metastasis has occurred, there is no FDA-approved targeted therapy to increase patient overall survival. Although well-understood pathways are activated by GNAQ/GNA11 mutations in uveal melanoma, targeting known downstream effectors has thus far have not yielded effective treatments. In this study, we used a novel proteomics approach to identify new therapeutic targets. We demonstrate that the knockdown of MARK3 and STK10 results in decreased growth of uveal melanoma cells, and their activity and expression, respectively, is regulated by Gαq/11 signaling.Supplementary files from Chapter 2 are available under the file name "Supplementary tables S1-12". These files contain gene set data spreadsheets. A material and methods spreadsheet from Chapter 3 is available under the file name "Supplementary table methods".