Novel Oligoamine Analogues Inhibit Lysine-Specific Demethylase 1 and Induce Reexpression of Epigenetically Silenced Genes

Abstract

Purpose: Abnormal DNA CpG island hypermethylation and transcriptionally repressive histone modifications are associated with the aberrant silencing of tumor suppressor genes. Lysine methylation is a dynamic, enzymatically controlled process. Lysinespecific demethylase 1 (LSD1) has recently been identified as a histone lysine demethylase. LSD1 specifically catalyzes demethylation of mono-and dimethyl-lysine 4 of histone 3 (H3K4), key positive chromatin marks associated with transcriptional activation. We hypothesized that a novel class of oligoamine analogues would effectively inhibit LSD1 and thus cause the reexpression of aberrantly silenced genes. Experimental Design: Human colorectal cancer cells were treated with the oligoamines and changes in mono-and dimethyl-H3K4 and other chromatin marks were monitored. In addition, treated cells were evaluated for the reexpression of the aberrantly silenced secreted frizzled-related proteins (SFRP) Wnt signaling pathway antagonist genes. Finally, the effects of the LSD1 inhibitors were evaluated in an in vivo xenograft model. Results: Treatment of HCT116 human colon adenocarcinoma cells in vitro resulted in increased H3K4 methylation and reexpression of silenced SFRP genes. This reexpression is also accompanied by a decrease in H3K9me2 repressive mark. Importantly, cotreatment with low doses of oligoamines and a DNA methyltransferase inhibitor highly induces the reexpression of the aberrantly silenced SFRP2 gene and results in significant inhibition of the growth of established tumors in a human colon tumor model in vivo. Conclusions: The use of LSD1-inhibiting oligoamine analogues in combination with DNA methyltransferase inhibitors represents a highly promising and novel approach for epigenetic therapy of cancer. (Clin Cancer Res 2009;15(23):7217-28) Epigenetics refers to heritable changes in gene expression patterns that are not regulated by changes in the primary DNA sequence. In cancer, epigenetic silencing of gene expression, including of tumor suppressor genes, is a common occurrence (1) that is associated with abnormal DNA methylation patterns and changes in covalent histone modifications (2). The amino-terminal tails of histones are subject to several posttranslational modifications, including acetylation, phosphorylation, and methylation, which are closely tied to transcriptional regulation, DNA replication, and DNA repair (2). As shown by the regulation of histone acetylation by histone acetyltransferases and histone deacetylases (HDAC), the addition and removal of these posttranslational modifications is a dynamic process. A similar dynamic regulation occurs for histone methylation with histone methyltransferases for the addition of methyl groups, and we recently discovered families of enzymes for specific histone demethylation. The first of these demethylating enzymes identified was the lysine-specific demethylase (LSD1/KDM1; ref.3), a flavin adenine dinucleotide (FAD)-dependent amine oxidase, which interacts directly with CoREST and HDAC1/2 pro...

Epigenetic Modifications: Therapeutic Potential in Cancer

“…LSD1 inhibited the proliferation of pluripotent cancer cells, including teratocarcinoma, embryonic carcinoma, seminoma or embryonic stem cells that express the stem cell markers Oct4 and Sox2, and colon cancer cells (Wang et al 2011). Treatment of the colon cancer cells with LSD1 inhibitors (such as SL11144) increases methylation at H3K4, decreases H3K9 methylation, and restores the expression of SFRP2, indicating the specificity of LSD1 and its inhibitors (Huang et al 2009). Its inhibition in neuroblastoma results in decreased proliferation in vitro and reduced xenograft growth (Schulte et al 2009).…”

Impairment of prostate cancer cell growth by a selective and reversible lysine‐specific demethylase 1 inhibitor

“…17 One milligram peptide of histone H3 (residues [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] carrying one or two methyl groups at lysine 4 were incubated with 2 lg of GST-LSD1 in the absence or presence of Namoline. The reaction mixture was incubated in demethylation buffer for 4 hr at 37 C and analyzed by mass spectroscopy.…”

“…[7][8][9][10][11][12][13] However, these amine oxidase inhibitors including clorgyline, pargyline, tranylcypromine, polyamines and derivatives thereof, many of them do not selectively target LSD1 and therefore, limits their use as therapeutics owing to potential side effects. In this study, we found a novel and selective LSD1 inhibitor called Namoline by combining protein structure similarity clustering and in vitro screening.…”

Epigenetic regulation of cancer growth by histone demethylases

“…Further evidences on collaborative actions of LSD1 and DNMTs in epigenetic silencing of tumor suppressor genes were provided by Huang et al They showed that a combination of LSD1 inhibitors and a DNMT inhibitor has proven to be highly efficient in reactivating aberrantly silenced genes in cancer and led to profound inhibition of the growth of human colon cancer xenografts in nude mice. 21 The oncogenic potential of LSD1 could also be the result of the p53 antagonizing action of LSD1. LSD1 can control the tumor suppressor activity of p53 by directly demethylating a specific p53 lysine (Lys370me2/1), which is required for efficient binding to the transcriptional coactivator p53-binding protein-1.…”