title: Inhibition of leukemic cell growth by a novel anti-cancer drug (GUT-70) from calophyllum brasiliense that acts by induction of apoptosis.
abstract: During our search for cancer chemopreventing compounds derived from plant sources, we discovered that the natural product GUT-70, isolated from the stem bark of Calophyllum brasiliense collected in Brazil, significantly inhibits the growth of leukemic cells. GUT-70, characterized as a tricyclic coumarin, 5-methoxy-2,2-dimethyl-6-(2-methyl-1-oxo-2-butenyl) -10-propyl-2H,8H-benzo[1,2-b;3,4-b']dipyran-8-one (C(23)H(26)O(5)), inhibited all 6 human leukemic cell lines evaluated, including the P-glycoprotein overexpressing cell line, in a concentration and time-dependent manner with IC(50) values from 2-5 microM. Furthermore, GUT-70 did not inhibit colony formation by normal hematopoietic progenitors up to 30 microM and also did not inhibit the proliferation of normal human hepatocytes up to 30 microM. GUT-70 activated the caspase 2, 3, 8 and 9, and induced the apoptosis in leukemic cells, which was inhibited by caspase inhibitors. GUT-70 induced anti-leukemic effects independent of the p53-p2l(WAFl/CIP1) pathway and increased the overall expression of p27(KIP1) and p57(KIP2), to stop the cell cycle at the G(1)/S transition. Thus, a novel anti-cancer drug, GUT-70 isolated from the stem bark of C. brasiliense induces caspase-mediated and p53-independent apoptosis to overcome multidrug resistance and may become a potent leukemia therapeutics.
authors.affiliation: Department of Transfusion Medicine and Cell Therapy, Kyoto University Hospital, Kyoto, Japan. shkimu@kuhp.kyoto-u.ac.jp
authors.forename: Shinya
authors.initials: S
authors.lastname: Kimura
authors.forename: Chihiro
authors.initials: C
authors.lastname: Ito
authors.forename: Naoto
authors.initials: N
authors.lastname: Jyoko
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Segawa
authors.forename: Junya
authors.initials: J
authors.lastname: Kuroda
authors.forename: Masayuki
authors.initials: M
authors.lastname: Okada
authors.forename: Souichi
authors.initials: S
authors.lastname: Adachi
authors.forename: Tatsutoshi
authors.initials: T
authors.lastname: Nakahata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yuasa
authors.forename: Valdir Cechinel
authors.initials: VC
authors.lastname: Filho
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Furukawa
authors.forename: Taira
authors.initials: T
authors.lastname: Maekawa
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001938:Brazil; D029759:Calophyllum; D020169:Caspases / Q000187:drug effects*; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000188:drug therapy; D003374:Coumarins / Q000494:pharmacology*; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D007938:Leukemia / Q000188:drug therapy*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D003374:Coumarins; C493688:GUT-70; D020169:Caspases