The Role Of The Microphthalmia Associated Transcription Factor In Autophagy Regulation In Melanoma

Autophagy is considered a therapeutic target in various cancer types, including melanoma. The transcription factors TFEB and TFE3 have been shown to play a key role in autophagy regulation in various cell types by affecting gene expression required for this process. A close relative to these factors is the transcription factor MITF; often termed the master regulator of melanocyte development and function. MITF activity has also been shown to be important for various stages of melanoma formation and progression. Analysis of The Cancer Genome Atlas expression data from melanoma tumors reveals that MITF expression correlates with lysosomal and autophagy gene expression in metastatic tumors. Furthermore, analysis of expression data from 23 melanoma cell lines shows that MITF expression correlates with lysosomal and autophagy gene expression, and the analysis of available MITF ChIP sequencing data shows that MITF binds the promoters of lysosomal and autophagy genes. This binding was experimentally verified by ChIP experiments in 501Mel melanoma cells. MITF over-expression and knock down experiments show effects of MITF on lysosomal and autophagy gene expression, as well as an effect on the autophagy activity. Autophagy is high in melanoma and has been linked to tolerance against cancer treatment. We have found that MITF regulates autophagy genes and activity in melanoma cell lines. In light of both MITF and autophagy being considered a therapeutic target in melanoma, this relationship needs to be taken into consideration. Citation Format: Katrin Moller, Sara Sigurbjornsdottir, Remina Dilixiati, Solveig H. Brynjolfsdottir, Lionel Larue, Vesteinn Thorsson, Eirikur Steingrimsson, Margret H. Ogmundsdottir. The role of the microphthalmia associated transcription factor in autophagy regulation in melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 224.