title: Cajanol, a novel anticancer agent from Pigeonpea [Cajanus cajan (L.) Millsp.] roots, induces apoptosis in human breast cancer cells through a ROS-mediated mitochondrial pathway.
abstract: Cajanol (5-hydroxy-3-(4-hydroxy-2-methoxyphenyl)-7-methoxychroman-4-one) is an isoflavanone from Pigeonpea [Cajanus cajan (L.) Millsp.] roots. As the most effective phytoalexin in pigeonpea, the cytotoxic activity of cajanol towards cancer cells has not been report as yet. In the present study, the anticancer activity of cajanol towards MCF-7 human breast cancer cells was investigated. In order to explore the underlying mechanism of cell growth inhibition of cajanol, cell cycle distribution, DNA fragmentation assay and morphological assessment of nuclear change, ROS generation, mitochondrial membrane potential (DeltaPsim) disruption, and expression of caspase-3 and caspase-9, Bax, Bcl-2, PARP and cytochrome c were measured in MCF-7 cells. Cajanol inhibited the growth of MCF-7 cells in a time and dose-dependent manner. The IC(50) value was 54.05 microM after 72 h treatment, 58.32 microM after 48 h; and 83.42 microM after 24h. Cajanol arrested the cell cycle in the G2/M phase and induced apoptosis via a ROS-mediated mitochondria-dependent pathway. Western blot analysis showed that cajanol inhibited Bcl-2 expression and induced Bax expression to desintegrate the outer mitochondrial membrane and causing cytochrome c release. Mitochondrial cytochrome c release was associated with the activation of caspase-9 and caspase-3 cascade, and active-caspase-3 was involved in PARP cleavage. All of these signal transduction pathways are involved in initiating apoptosis. To the best of our knowledge, this is the first report demonstrating the cytotoxic activity of cajanol towards cancer cells in vitro.
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China.
authors.forename: Meng
authors.initials: M
authors.lastname: Luo
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.forename: Yuangang
authors.initials: Y
authors.lastname: Zu
authors.forename: Yujie
authors.initials: Y
authors.lastname: Fu
authors.forename: Su
authors.initials: S
authors.lastname: Zhang
authors.forename: Liping
authors.initials: L
authors.lastname: Yao
authors.forename: Thomas
authors.initials: T
authors.lastname: Efferth
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D036561:Cajanus / Q000737:chemistry*; D045744:Cell Line, Tumor; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000094162:Phytoalexins
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D007529:Isoflavones; D017382:Reactive Oxygen Species; C471767:cajanol; D000094162:Phytoalexins