Project description:Complex regulatory networks control epithelial-to-mesenchymal transition (EMT) but the underlying epigenetic control is poorly understood. Lysine-specific demethylase 1 (LSD1) is a key histone demethylase that alters the epigenetic landscape. Here we explored the role of LSD1 in global epigenetic regulation of EMT, cancer stem cells (CSCs), the tumour microenvironment, and therapeutic resistance in breast cancer. LSD1 induced pan-genomic gene expression in networks implicated in EMT and selectively elicits gene expression programs in CSCs whilst repressing non-CSC programs. LSD1 phosphorylation at serine-111 (LSD1-s111p) by chromatin anchored protein kinase C-theta (PKC-θ), is critical for its demethylase and EMT promoting activity and LSD1-s111p is enriched in chemoresistant cells in vivo. LSD1 couples to PKC-θ on the mesenchymal gene epigenetic template promotes LSD1-mediated gene induction. In vivo, chemotherapy reduced tumour volume, and when combined with an LSD1 inhibitor, abrogated the mesenchymal signature and promoted an innate, M1 macrophage-like tumouricidal immune response. Circulating tumour cells (CTCs) from metastatic breast cancer (MBC) patients were enriched with LSD1 and pharmacological blockade of LSD1 suppressed the mesenchymal and stem-like signature in these patient-derived CTCs. Overall, LSD1 inhibition may serve as a promising epigenetic adjuvant therapy to subvert its pleiotropic roles in breast cancer progression and treatment resistance.
Project description:Neuroblastoma (NB) with MYCN amplification is a highly metastatic tumor in children, and unraveling the key players involved in MYCN-induced invasion may identify new targets for therapy. Epithelial-mesenchymal transition (EMT) plays a critical role in promoting metastasis and we have recently determined that MYCN interacts with LSD1, a histone de-methylase flavin oxidase, which has been found to promote EMT. We show here that LSD1 affects motility and invasiveness of NB cells through transcription modulation of the metastasis suppressor NDRG1, N-Myc Downstream-Regulated Gene 1. LSD1 co-localizes with MYCN at the promoter region of the NDRG1 gene and it inhibits its expression. LSD1-inhibition relieves NDRG1 repression induced by MYCN with concomitant block of motility and invasiveness of NB cells, and such effects were recapitulated by overexpressing NDRG1. Moreover, we found that low NRDG1 and high LSD1 levels in NB patients were associated with poor survival. These data suggest that LSD1 inhibition may knock down the ability of MYCN-amplified Neuroblastomas to metastasize. Our findings elucidate a mechanism of how MYCN/LSD1 control motility and invasiveness of NB cells through transcription regulation of NDRG1 expression and they suggest that pharmacological targeting of LSD1 could inhibit the NB metastatic process.
Project description:HOTAIR is a scafold long non-coding RNA tethering PRC2 and Lsd1/REST/coREST complexes to gene promoters to repress transcription of genes involved in epithelial to mesenchymal transition (EMT). To decipher a role of the Lsd1 in HOTAIR function we generated epithelial cell lines expressing full length and truncated versions of HOTAIR missing first 5'-300 (Epi-HOTΔP) and last 3'-500 bp (Epi-HOTΔL) interacting with HOTAIR partners. These cell lines were further used to determine Lsd1 binding sites using chromatin immunoprecipitation approach.