1.Identification of 2,4-diamino-6,7-dimethoxyquinoline derivatives as G9a inhibitors†Electronic supplementary information (ESI) available. See DOI: 10.1039/c4md00274a.
Srimongkolpithak N1, Sundriyal S2, Li F3, Vedadi M3, Fuchter MJ2. Medchemcomm. 2014 Dec 19;5(12):1821-1828. Epub 2014 Sep 11.
G9a is a histone lysine methyltransferase (HKMT) involved in epigenetic regulation via the installation of histone methylation marks. 6,7-Dimethoxyquinazoline analogues, such as BIX-01294, are established as potent, substrate competitive inhibitors of G9a. With an objective to identify novel chemotypes for substrate competitive inhibitors of G9a, we have designed and synthesised a range of heterocyclic scaffolds, and investigated their ability to inhibit G9a. These studies have led to improved understanding of the key pharmacophoric features of BIX-01294 and the identification of a new core quinoline inhibitory scaffold, which retains excellent potency and high selectivity. Molecular docking was carried out to explain the observed in vitro data.
2.A Unique Virulence Gene Occupies a Principal Position in Immune Evasion by the Malaria Parasite Plasmodium falciparum.
Ukaegbu UE1, Zhang X2, Heinberg AR1, Wele M3, Chen Q4, Deitsch KW1. PLoS Genet. 2015 May 19;11(5):e1005234. doi: 10.1371/journal.pgen.1005234. eCollection 2015.
Mutually exclusive gene expression, whereby only one member of a multi-gene family is selected for activation, is used by the malaria parasite Plasmodium falciparum to escape the human immune system and perpetuate long-term, chronic infections. A family of genes called var encodes the chief antigenic and virulence determinant of P. falciparum malaria. var genes are transcribed in a mutually exclusive manner, with switching between active genes resulting in antigenic variation. While recent work has shed considerable light on the epigenetic basis for var gene activation and silencing, how switching is controlled remains a mystery. In particular, switching seems not to be random, but instead appears to be coordinated to result in timely activation of individual genes leading to sequential waves of antigenically distinct parasite populations. The molecular basis for this apparent coordination is unknown. Here we show that var2csa, an unusual and highly conserved var gene, occupies a unique position within the var gene switching hierarchy.
3.Effect of BIX-01294 on H3K9me2 levels and the imprinted gene Snrpn in mouse embryonic fibroblast cells.
Chen P1, Yao JF2, Huang RF3, Zheng FF4, Jiang XH5, Chen X5, Chen J5, Li M5, Huang HF5, Jiang YP6, Huang YF7, Yang XY8. Biosci Rep. 2015 Aug 18;35(5). pii: e00257. doi: 10.1042/BSR20150064.
Histone H3 lysine 9 dimethylation (H3K9me2) hypermethylation is thought to be a major influential factor in cellular reprogramming, such as somatic cell nuclear transfer (SCNT) and induction of pluripotent stem cells (iPSCs). The diazepin-quinazolin-amine derivative (BIX-01294) specifically inhibits the activity of histone methyltransferase EHMT2 (euchromatic histone-lysine N-methyltransferase 2) and reduces H3K9me2 levels in cells. The imprinted gene small nuclear ribonucleoprotein N (Snrpn) is of particular interest because of its important biological functions. The objective of the present study was to investigate the effect of BIX-01294 on H3K9me2 levels and changes in Snrpn DNA methylation and histone H3K9me2 in mouse embryonic fibroblasts (MEFs). Results showed that 1.3 μM BIX-01294 markedly reduced global levels of H3K9me2 with almost no cellular toxicity. There was a significant decrease in H3K9me2 in promoter regions of the Snrpn gene after BIX-01294 treatment.
4.G9a-mediated histone methylation regulates cadmium-induced male fertility damage in pubertal mice.
Li M1, Liu C1, Yang L1, Zhang L1, Chen C1, He M1, Lu Y1, Feng W2, Pi H1, Zhang Y1, Zhong M1, Yu Z3, Zhou Z4. Toxicol Lett. 2016 Apr 6;252:11-21. doi: 10.1016/j.toxlet.2016.04.004. [Epub ahead of print]
Increasing evidence suggests that cadmium (Cd) is associated with male fertility damage. However, the effects of histone modification on Cd-induced male fertility damage remain obscure. This study aims to evaluate the roles of histone methylation mediated by euchromatin histone methyltransferase (EHMT2/G9a) in regulating Cd-induced male fertility damage. We exposed 4-week-old male C57BL/6J mice to Cd by intraperitoneal injection at 2mg/kg for 1, 3 and 5days. Our data showed that Cd exposure decreased the numbers of impregnated females and litter sizes, which was concomitant with sperm count reduction, histological changes in the cauda epididymal ducts and seminiferous epithelium, and testicular cell apoptosis as evaluated by terminal dUTP nick-end labeling (TUNEL) assay and immunoblotting with increased levels of cleaved caspase 3, PARP and Bax and a decreased level of Bcl-2. Cd-induced male fertility damage was accompanied by enhanced G9a activity followed by increased histone H3 lysine 9 monomethylation (H3K9me1) and dimethylation (H3K9me2) in testes.