Polyamine analogs modulate gene expression by inhibiting lysine-specific demethylase 1 (LSD1) and altering chromatin structure in human breast cancer cells

Abstract

Aberrant epigenetic repression of gene expression has been implicated in most cancers, including breast cancer. The nuclear amine oxidase, lysine-specific demethylase 1 (LSD1) has the ability to broadly repress gene expression by removing the activating mono- and di-methylation marks at the lysine 4 residue of histone 3 (H3K4me1 & me2). Additionally, LSD1 is highly expressed in estrogen receptor α negative (ER−) breast cancer cells. Since epigenetic marks are reversible, they make attractive therapeutic targets. Here we examine the effects of polyamine analogue inhibitors of LSD1 on gene expression, with the goal of targeting LSD1 as a therapeutic modality in the treatment of breast cancer. Exposure of the ER-negative human breast cancer cells, MDA-MB-231, to the LSD1 inhibitors, 2d or PG11144, significantly increases global H3K4me1 and H3K4me2, and alters gene expression. Array analysis indicated that 98 (75 up and 23 down) and 477 (237 up and 240 down) genes changed expression by at least 1.5-fold or greater after treatment with 2d and PG11144, respectively. The expression of twelve up-regulated genes by 2d and fourteen up-regulated genes by PG11144 was validated by quantitative RT-PCR. Quantitative chromatin immunoprecipitation (ChIP) analysis demonstrated that up-regulated gene expression by polyamine analogues is associated with increase of the active histone marks H3K4me1, H3K4me2 and H3K9ac, and decrease of the repressive histone marks H3K9me2 and H3K27me3, in the promoter regions of the relevant target genes. These data indicate that the pharmacologic inhibition of LSD1 can effectively alter gene expression and that this therapeutic strategy has potential.

Trithorax monomethylates histone H3K4 and interacts directly with CBP to promote H3K27 acetylation and antagonize Polycomb silencing

“…Incubating Drosophila S2 cells for 3 days in media containing 40 μM and 80 μM bisguanidine polyamine analog, which inhibits human LSD1 in breast cancer cells (Zhu et al, 2012), significantly increased their H3K4me1 level, as expected, and also increased their H3K27ac level, while CBP and H3K4me3 levels were unchanged (Fig. 7D, lanes 4 and 5).…”

Functional interaction of histone deacetylase 5 (HDAC5) and lysine-specific demethylase 1 (LSD1) promotes breast cancer progression

“…A role for elevated expression of LSD1 has been implicated in tumorigenesis in various cancers including breast cancer (3, 5–9). Studies from our and other laboratories consistently showed that inhibition of LSD1 hindered proliferation of breast cancer cells (6, 8, 10). Lim et al reported that LSD1 is highly expressed in ER-negative breast cancers (6).…”

Role of Epigenetic Modifications in Luminal Breast Cancer

“…They promote re-expression of silenced genes of the GATA family of transcription factors that are important in the development of colon cancers [48]. These LSD1 inhibitors alter promoter activity of multiple genes in breast cancer cells and are postulated to have considerable therapeutic potential [49]. …”