Transcriptional regulators FOXD1 and RBFOX2 contribute to metastatic capacity in BAP1 mut uveal melanoma

Abstract Uveal melanoma is the most prevalent primary intraocular cancer, with a significant metastatic risk. This risk is dependent on the genetic drivers. Secondary mutations in EIF1AX, SF3B1 and BAP1 correlate with clinical outcomes and are recognized for their distinct transcriptomic and epigenetic profiles. Previously, we identified 480 genes involved in the development of ocular melanocytes. Top ranking genes RBFOX2 and FOXD1 were significantly associated with BAP1 UM and were independently correlated to poor progression. However, it is uncertain whether either RBFOX2 or FOXD1 have biological contribution to disease progression or are solely indicative. This study investigates if and how these high-risk associated transcription regulators FOXD1 and RBFOX2 could influence tumor progression through knock-out and overexpression models. Our results indicate that loss of RBFOX2 affects cell morphology, attachment and proliferation, particularly in BAP1 neg cells. Additionally, both RBFOX2 and FOXD1 contribute to tumor growth and dissemination in zebrafish xenografts. Loss of either RBFOX2 or FOXD1 reduced tumor volume and cell dissemination, with the greatest effects seen in BAP1 neg cells. Overexpression models demonstrated different morphological and invasive behavior depending on the genetic background, suggesting complex roles in a context dependent fashion. Overexpression of RBFOX2 did not alter BAP1 pos cells yet made BAP1 neg cells more aggressive in vitro and in vivo . This study underscores the influence of RBFOX2 and FOXD1 as important factors for UM progression.