Data from <i>SDHD</i> Promoter Mutations Ablate GABP Transcription Factor Binding in Melanoma

Abstract

<div>Abstract<p><i>SDHD</i> encodes subunit D of the succinate dehydrogenase complex, an integral membrane protein. Across cancer types, recurrent <i>SDHD</i> promoter mutations were reported to occur exclusively in melanomas, at a frequency of 4% to 5%. These mutations are predicted to disrupt consensus ETS transcription factor–binding sites and are correlated with both reduced <i>SDHD</i> gene expression and poor prognosis. However, the consequence of these mutations on <i>SDHD</i> expression in melanoma is still unclear. Here, we found that expression of <i>SDHD</i> in melanoma correlated with the expression of multiple ETS transcription factors, particularly in <i>SDHD</i> promoter wild-type samples. Consistent with the predicted loss of ETS transcription factor binding, we observed that recurrent hotspot mutations resulted in decreased luciferase activity in reporter assays. Furthermore, we demonstrated specific GABPA and GABPB1 binding to probes containing the wild-type promoter sequences, with binding disrupted by the <i>SDHD</i> hotspot promoter mutations in both quantitative mass spectrometry and band-shift experiments. Finally, using siRNA-mediated knockdown across multiple melanoma cell lines, we determined that loss of GABPA resulted in reduced SDHD expression at both RNA and protein levels. These data are consistent with a key role for GABPA/B1 as the critical ETS transcription factors deregulating <i>SDHD</i> expression in the context of highly recurrent promoter mutations in melanoma and warrant a detailed search for other recurrent promoter mutations that create or disrupt GABPA consensus sequences. <i>Cancer Res; 77(7); 1649–61. ©2017 AACR</i>.</p></div>