Browsing by Subject "LSD1"

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    The histone demethylase LSD1 regulates inner ear progenitor differentiation through interactions with Pax2 and the NuRD repressor complex
    (Public Library of Science, 2018-01-25) Patel, Dharmeshkumar; Shimomura, Atsushi; Majumdar, Sreeparna; Holley, Matthew C.; Hashino, Eri; Otolaryngology -- Head and Neck Surgery, School of Medicine
    The histone demethylase LSD1 plays a pivotal role in cellular differentiation, particularly in silencing lineage-specific genes. However, little is known about how LSD1 regulates neurosensory differentiation in the inner ear. Here we show that LSD1 interacts directly with the transcription factor Pax2 to form the NuRD co-repressor complex at the Pax2 target gene loci in a mouse otic neuronal progenitor cell line (VOT-N33). VOT-N33 cells expressing a Pax2-response element reporter were GFP-negative when untreated, but became GFP positive after forced differentiation or treatment with a potent LSD inhibitor. Pharmacological inhibition of LSD1 activity resulted in the enrichment of mono- and di-methylation of H3K4, upregulation of sensory neuronal genes and an increase in the number of sensory neurons in mouse inner ear organoids. Together, these results identify the LSD1/NuRD complex as a previously unrecognized modulator for Pax2-mediated neuronal differentiation in the inner ear.
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    Lysine-Specific Demethylase 1 Mediates AKT Activity and Promotes Epithelial-to-Mesenchymal Transition in PIK3CA-Mutant Colorectal Cancer
    (American Association for Cancer Research, 2020-02-01) Miller, Samuel A.; Policastro, Robert A.; Savant, Sudha S.; Sriramkumar, Shruthi; Ding, Ning; Lu, Xiaoyu; Mohammad, Helai P.; Cao, Sha; Kalin, Jay H.; Cole, Philip A.; Zentner, Gabriel E.; O'Hagan, Heather M.; Medical and Molecular Genetics, School of Medicine
    Activation of the epithelial-mesenchymal transition (EMT) program is a critical mechanism for initiating cancer progression and migration. Colorectal cancers (CRCs) contain many genetic and epigenetic alterations that can contribute to EMT. Mutations activating the PI3K/AKT signaling pathway are observed in >40% of patients with CRC contributing to increased invasion and metastasis. Little is known about how oncogenic signaling pathways such as PI3K/AKT synergize with chromatin modifiers to activate the EMT program. Lysine Specific Demethylase 1 (LSD1) is a chromatin-modifying enzyme that is overexpressed in colorectal cancer (CRC) and enhances cell migration. In this study we determine that LSD1 expression is significantly elevated in CRC patients with mutation of the catalytic subunit of PI3K, PIK3CA, compared to CRC patients with WT PIK3CA. LSD1 enhances activation of the AKT kinase in CRC cells through a non-catalytic mechanism, acting as a scaffolding protein for the transcription-repressing CoREST complex. Additionally, growth of PIK3CA mutant CRC cells is uniquely dependent on LSD1. Knockdown or CRISPR knockout of LSD1 blocks AKT-mediated stabilization of the EMT-promoting transcription factor Snail and effectively blocks AKT-mediated EMT and migration. Overall we uniquely demonstrate that LSD1 mediates AKT activation in response to growth factors and oxidative stress, and LSD1-regulated AKT activity promotes EMT-like characteristics in a subset of PIK3CA mutant cells. Implications Our data supports the hypothesis that inhibitors targeting the CoREST complex may be clinically effective in CRC patients harboring PIK3CA mutations.