Identification of 4 0 -O-b-D-glucosyl-5-O-methylvisamminol as a novel epigenetic suppressor of histone H3 phosphorylation at Ser10 and its interaction with 14-3-3e Jong-Su Kang a , Young-Won Chin a , Kyeong Lee a , Young-Woo Kim a , Bu Young Choi b , Young-Sam Keum a,⇑ a College of Pharmacy, Dongguk University, Goyang, Gyeonggi-do 410-773, Republic of Korea b Department of Pharmaceutical Science and Engineering, Seowon University, Cheongju, Chungbuk 361-742, Republic of Korea article info Article history: Received 13 January 2014 Revised 8 June 2014 Accepted 1 July 2014 Available online 27 August 2014 Keywords: 4 0 -O-b-D-Glucosyl-5-O-methylvisamminol Histone phosphorylation 14-3-3e Aurora B kinase abstract Natural compounds are regarded as a rich source for potential anti-inflammatory and anti-carcinogenic agents. Increasing evidence indicates that histone phosphorylation at Ser10 is a marker for cell cycle progression during the mitosis and the induction of immediate pro-inflammatory genes during the inter- phase. In the present study, we have screened our in-house natural compounds to find out new chemical inhibitor(s) of histone H3 phosphorylation at Ser10. As a result, we observed that a-amyrin, oleanolic acid, marliolide, and 4 0 -O-b-D-glucosyl-5-O-methylvisamminol decreased the levels of histone H3 phos- phorylation at Ser10 and c-Jun. In particular, we observed that 4 0 -O-b-D-glucosyl-5-O-methylvisamminol suppressed the direct interaction of histone H3 with 14-3-3e, inhibited the aurora B kinase activity and delayed the mitotic cell cycle progression. We reports 4 0 -O-b-D-glucosyl-5-O-methylvisamminol as the first epigenetic natural chemical inhibitor that can abrogates the mitotic cell cycle progression and imme- diate pro-inflammatory gene expressions via suppression of histone H3 phosphorylation at Ser10 and its interaction with 14-3-3e. Ó 2014 Elsevier Ltd. All rights reserved. When cells receive internal or external cues, intracellular signaling pathways are quickly initiated to alter patterns of gene expression. 1 The modes of gene activation or suppression are largely attributable to the changes in diverse post-translational modifications of histones, such as phosphorylation, methylation, acetylation, ADP-ribosylation and mono-ubiquitination. 2 Previous studies have demonstrated that histone H3 phosphorylation at Ser10 (abbreviated as p-H3S10) mediates two important biological functions, depending on the cell cycle status: it is directly associ- ated with cell cycle progression during the mitosis and transcrip- tional activation of immediate pro-inflammatory genes during the interphase. 3 Therefore, it can be surmised that suppressing p-H3S10 might serve as a feasible epigenetic strategy to inhibit the mitotic cell cycle progression as well as transcriptional activa- tion of immediate pro-inflammatory genes during the interphase. While aurora B kinase is the sole kinase that can directly phosphor- ylate histone H3 at Ser10 during the mitosis, there exist a large number of kinases responsible for p-H3S10 during the interphase. 4 The exact reason why such a large number of upstream kinases are necessary during the interphase for a single histone phosphoryla- tion mark, e.g. p-H3S10 is currently unclear. In the present study, we have attempted to find out novel natural chemical(s) that can inhibit both p-H3S10 and c-Jun expression. It should be stated that the c-Jun level was measured as a representative read-out for immediate pro-inflammatory genes, induced by p-H3S10 during the interphase. We have exposed human colon cancer HT-29 cells to individual natural compounds from our in-house natural chemical library (Table 1) 5 and collected the cell lysates to measure the levels of p-H3S10 and c-Jun by Western blot analysis. 6 As a result, we observed that 4 out of 49 natural compounds completely diminished the levels of p-H3S10 and c-Jun (Fig. 1). They were a-amyrin (32), oleanolic acid (34), marliolide (46), and 4 0 -O-b-D-glucosyl-5-O-methylvisammi- nol (48)(Fig. 2A). Although it seems possible to assume that sup- pressing the c-Jun expression by these chemicals is directly associated with a decreased p-H3S10 level, finding out which kinase(s) they did target to suppress p-H3S10 seems an impractical task due to the presence of a vast number of p-H3S10 kinases responsible for transcriptional activation of pro-inflammatory genes during the interphase. 7 Phosphorylated histones serve as a platform to receive informa- tion from the upstream signals and transmit it to the downstream http://dx.doi.org/10.1016/j.bmcl.2014.07.005 0960-894X/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +82 31 961 5215. E-mail address: keum03@dongguk.edu (Y.-S. Keum). Bioorganic & Medicinal Chemistry Letters 24 (2014) 4763–4767 Contents lists available at ScienceDirect Bioorganic & Medicinal Chemistry Letters journal homepage: www.elsevier.com/locate/bmcl