HMGA1 is an oncogene encoding for an architectural transcription factor that affects fundamental cell processes, leading to neoplastic transformation.
The two main mechanisms by which HMGA1 protein is known to be involved in cancer concern the regulation of gene expression by altering DNA structure and interacting with a conspicuous number of transcription factors. Here we provide evidence of an additional level of gene expression regulation exploited by HMGA1 to exert its oncogenic activity. Starting from protein-protein interaction data showing that HMGA1 interacts with histones, we show that HMGA1 regulates gene expression by affecting the epigenetic status of cancer cells. In particular, it modulates the signalling cascade mediated by the RAS/RAF/MEKK/ERK/RSK2 pathway regulating the levels of histone H3 phosphorylation at Serine 10 and Serine 28. We demonstrate that the down-regulation of these two H3 post-translational modifications by HMGA1 silencing and by inhibitors of the RAS/RAF/MEKK/ERK pathway is linked to cell migration decrease and morphological changes resembling the mesenchymal to epithelial transition.
