Defining the role of MAFG in melanocyte transformation and melanoma development

Over the past decade, non-genetic mechanisms have emerged as powerful drivers of melanoma initiation and progression. These mechanisms include epigenetic, transcriptional, and post-transcriptional alterations that lead to dynamic and reversible changes in gene expression programs. Among these, the deregulation of transcription factors plays particularly potent roles in melanomagenesis, and we have identified the transcription factor MAFG as a critical player in melanoma development. MAFG exhibits increased expression levels in human melanoma and promotes the oncogenic behavior of melanoma cells. Additionally, overexpression of MAFG in a genetic mouse model of melanoma dramatically accelerated melanomagenesis. Conversely, genetic deletion of MAFG in a genetic mouse model of aggressive melanoma completely prevented the transition from nevi to frank melanomas, indicating MAFG’s critical role during tumor initiation. The oncogenic function of MAFG may, in part, be mediated by a phenotype switch and an interaction with the lineage transcription factor MITF. We hypothesize that MAFG acts as both a potent driver and a specific vulnerability in melanoma, making it a promising target for therapeutic intervention. However, critical questions remain about the cell biological and molecular influence of MAFG on melanomagenesis, which we will address in this proposal. Aim 1 will uncover the role of MAFG in melanocyte transformation and melanomagenesis. Using our ESC-GEMM platform, we will comprehensively evaluate MAFG’s role in melanocyte transformation, melanoma initiation, malignant progression, and metastasis across various genetic contexts. This Aim seeks to establish the foundational impact of MAFG in melanoma development. Aim 2 will decipher the oncogenic mechanisms of MAFG through its binding partners. We will investigate how MAFG cooperates with MITF to drive melanomagenesis and determine if MITF is required for the oncogenic effects of MAFG. Moreover, we will determine if the canonical binding partner BACH2 cooperates with MAFG to drive melanoma. This Aim will elucidate the molecular pathways by which MAFG exerts its oncogenic effects, focusing on its interaction with key transcriptional regulators. Aim 3 will define the vulnerability of melanoma to MAFG depletion. We will assess the molecular consequences of acute MAFG depletion in melanoma and perform a CRISPR screen to identify actionable upstream regulators of MAFG. This Aim will uncover potential therapeutic targets by highlighting the dependency of melanoma cells on MAFG. By addressing these Aims, our studies will provide critical insights into MAFG’s role in melanoma biology and pave the way for novel therapeutic strategies targeting MAFG and its downstream pathways. This work holds significant potential for improving outcomes for patients with metastatic melanoma, a currently intractable malignancy. Project Number: 1R01CA299434-01A1 | Fiscal Year: 2026 | NIH Institute/Center: National Cancer Institute (NCI) | Principal Investigator: Florian Karreth | Institution: H. LEE MOFFITT CANCER CTR & RES INST, TAMPA, FL | Award Amount: $607,249 | Activity Code: R01 | Study Section: Biochemical and Cellular Oncogenesis Study Section[BCO] View on NIH RePORTER: https://reporter.nih.gov/project-details/11290926