title: Involvement of histone H3 phosphorylation via the activation of p38 MAPK pathway and intracellular redox status in cytotoxicity of HL-60 cells induced by Vitex agnus-castus fruit extract.
abstract: We have demonstrated that an extract from the ripe fruit of Vitex angus-castus (Vitex), might be a promising anticancer candidate. In order to further provide a molecular rationale for clinical development in anticancer therapy, a detailed mechanism underlying the efficacy of Vitex against HL-60 cells was investigated. Vitex induced a dose- and time-dependent decrease in cell viability associated with induction of apoptosis and G(2)/M cell cycle arrest, both of which were suppressed by the addition of SB203580, an inhibitor for p38 MAPK. Furthermore, SB203580 significantly suppressed Vitex-induced phosphorylation of histone H3, a downstream molecule of p38 MAPK known to be involved in apoptosis induction in tumor cells. Notably, Vitex induced upregulation of intracellular ATP, known to bind its binding pocket inside activated p38 MAPK and to be required for the activation of p38 MAPK pathway. These results, thus, suggest that upregulation of intracellular ATP and phosphorylation of histone H3 are closely associated with the activation of p38 MAPK pathway, consequently contributing to Vitex-mediated cytotoxicity. Intriguingly, a significant decrease of intracellular ROS levels and downregulation of expression level of gp91(phox), an important component of NADPH oxidase, were observed in Vitex-treated cells. A greater decline in ROS levels along with enhanced apoptosis was observed after treatment with Vitex in combination with SnPP, an inhibitor specific for HO-1. Since NADPH oxidase and HO-1 are closely correlated to redox status associated with intracellular ROS levels, the two enzymes are suggested to be implicated in Vitex-mediated cytotoxicity in HL-60 cells by regulating ROS generation. We also suggest that activation of the p38 MAPK pathway may be dependent on the alterations of intracellular ATP levels, rather than that of intracellular ROS levels. These results may have important implications for appropriate clinical uses of Vitex and provide novel insights into the interaction between Vitex and other conventional drugs capable of affecting intracellular redox status.
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Hidetomo
authors.initials: H
authors.lastname: Kikuchi
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Bo
authors.initials: B
authors.lastname: Yuan
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Eisuke
authors.initials: E
authors.lastname: Yuhara
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Imai
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Ryota
authors.initials: R
authors.lastname: Furutani
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Fukushima
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Hazama
authors.affiliation: Department of Cultural History, Seisen University, Shinagawa-ku, Tokyo 141-0022, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Hirobe
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Ohyama
authors.affiliation: Department of Applied Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Takagi
authors.affiliation: Department of Clinical Molecular Genetics, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Hiroo
authors.initials: H
authors.lastname: Toyoda
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005638:Fruit; D018922:HL-60 Cells; D006657:Histones / Q000378:metabolism*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D010084:Oxidation-Reduction / Q000187:drug effects*; D010766:Phosphorylation / Q000187:drug effects; D008517:Phytotherapy / Q000379:methods; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020950:Vitex / Q000737:chemistry*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004365:Drugs, Chinese Herbal; D006657:Histones; C553090:Vitex agnus castus extract