GSE129078
The MITF-SOX10 regulated long non-coding RNA DIRC3 is a melanoma tumour suppressor
The MITF and SOX10 transcription factors regulate the expression of genes important for melanoma proliferation, invasion and metastasis. Despite growing evidence of the contribution of long non-coding RNAs (lncRNAs) in melanoma and other cancers, their functions within MITF-SOX10 transcriptional programmes is poorly investigated. Here, we identify 245 candidate melanoma associated lncRNAs whose loci are co-occupied by MITF-SOX10 and are enriched at active enhancer-like regions. We characterise the function and molecular mechanism of action of one of these lncRNAs, Disrupted In Renal Carcinoma 3 (DIRC3), and show that it operates as a MITF-SOX10 regulated tumour suppressor. DIRC3 depletion in human melanoma cells leads to increased anchorage-independent growth, a hallmark of malignant transformation, whilst melanoma patients classified by low DIRC3 expression have decreased survival. DIRC3 is a nuclear lncRNA that functions locally to activate expression of its neighbouring IGFBP5 tumour suppressor through modulation of chromatin structure and suppression of SOX10 binding to putative regulatory elements within the DIRC3 locus. In turn, DIRC3 dependent regulation of IGFBP5 impacts the expression of genes important for cell metabolism, oxidative phosphorylation and cancer. Our work indicates that lncRNA components of MITF-SOX10 networks are an important new class of melanoma regulators and candidate therapeutic targets. Overall design: 2 melanoma and 1 melanocyte cell lines were subjected to