Targeted DNA oxidation by LSD1–SMAD2/3 primes TGF-β1/ EMT genes for activation or repression

Abstract

The epithelial-to-mesenchymal transition (EMT) is a complex transcriptional program induced by transforming growth factor β1 (TGF-β1). Histone lysine-specific demethylase 1 (LSD1) has been recognized as a key mediator of EMT in cancer cells, but the precise mechanism that underlies the activation and repression of EMT genes still remains elusive. Here, we characterized the early events induced by TGF-β1 during EMT initiation and establishment. TGF-β1 triggered, 30–90 min post-treatment, a nuclear oxidative wave throughout the genome, documented by confocal microscopy and mass spectrometry, mediated by LSD1. LSD1 was recruited with phosphorylated SMAD2/3 to the promoters of prototypic genes activated and repressed by TGF-β1. After 90 min, phospho-SMAD2/3 downregulation reduced the complex and LSD1 was then recruited with the newly synthesized SNAI1 and repressors, NCoR1 and HDAC3, to the promoters of TGF-β1-repressed genes such as the Wnt soluble inhibitor factor 1 gene (WIF1), a change that induced a late oxidative burst. However, TGF-β1 early (90 min) repression of transcription also required synchronous signaling by reactive oxygen species and the stress-activated kinase c-Jun N-terminal kinase. These data elucidate the early events elicited by TGF-β1 and the priming role of DNA oxidation that marks TGF-β1-induced and -repressed genes involved in the EMT.

Towards a comprehensive view of 8-oxo-7,8-dihydro-2’-deoxyguanosine: Highlighting the intertwined roles of DNA damage and epigenetics in genomic instability

“…2 ). Supportive of this suggestion is a report that members of the Jumonji-type demethylases, a superfamily of oxygenases containing a Fe 2+ ion in their catalytic domain, can form complexes with LSD1 and H 2 O 2 produced by LSD1 activity reduced in the hydroxide ion by the oxidation of the Jumonji-contained Fe 2+ ion [ 49 ]. In close proximity of DNA molecules, this event may be responsible for the oxidation of nucleobases.…”

“…In close proximity of DNA molecules, this event may be responsible for the oxidation of nucleobases. Indeed, depletion of iron-containing JMJD2A, a Jumonji demethylase that interacts with LSD1 to activate TGF-β1-induced genes, inhibits the formation of nuclear 8-oxodG [ 49 ]. Together, these data support the hypothesis that • OH can be generated from H 2 O 2 produced at sites close enough to react with DNA.…”

“…The binding of enzymatically inactive OGG1 to 8-oxodG-containing promoter regions induces a bend in the DNA helix that facilitates the recruitment of specific TFs (NF-κB/RelA and Sp1) and the assembly of the transcriptional machinery [ 109 , 110 ]. Furthermore, increased levels of 8-oxodG have been found in binding regions of other TFs in association with the recruitment of the co-transcription factor LSD1 [ 43 – 47 , 49 , 50 , 111 ]. In this regard, another mechanism has been described to explain the epigenetic function of the 8-oxodG.…”

“…relaxation) for transcription initiation. This process of requiring LSD1-mediated DNA oxidation has been proven necessary for the transcription of the target genes of the estrogen receptor (ER), Myc, androgen receptor and TGF-β1 respectively [ 43 – 47 , 49 , 50 , 111 ].…”

LSD1: more than demethylation of histone lysine residues

“…It is beyond the scope of this review to list in detail all the nonhistone proteins whose activity is influenced by LSD1. We emphasize that LSD1, by controlling the methylation status of either histone or nonhistone proteins, is extensively involved in the control of several cellular processes in multiple cellular and tissue environments, including cell proliferation [92][93][94] , differentiation 95,96 , and stemness via the activation of the β-catenin signaling 97,98 ; the chemoresistance of several cancers, in which it appears to be upregulated 99 , the epithelial-mesenchymal transition (EMT) 100,101 , DNA methylation (with subsequent metastasis) 89,102 , cell motility 103,104 , angiogenesis 91 , and senescence 105 (Fig. 4).…”