title: Kaempferol induces ATM/p53-mediated death receptor and mitochondrial apoptosis in human umbilical vein endothelial cells.
abstract: Kaempferol is a member of the flavonoid compounds found in vegetables and fruits. It is shown to exhibit biological impact and anticancer activity, but no report exists on the angiogenic effect of kaempferol and induction of cell apoptosis in vitro. In this study, we investigated the role of kaempferol on anti-angiogenic property and the apoptotic mechanism of human umbilical vein endothelial cells (HUVECs). Our results demonstrated that kaempferol decreased HUVEC viability in a time- and concentration-dependent manner. Kaempferol also induced morphological changes and sub-G1 phase cell population (apoptotic cells). Kaempferol triggered apoptosis of HUVECs as detecting by DNA fragmentation, comet assay and immunofluorescent staining for activated caspase-3. The caspase signals, including caspase-8, -9 and -3, were time-dependently activated in HUVECs after kaempferol exposure. Furthermore, pre-treatment with a specific inhibitor of caspase-8 (Z-IETD-FMK) significantly reduced the activity of caspase-8, -9 and -3, indicating that extrinsic pathway is a major signaling pathway in kaempferol-treated HUVECs. Importantly, kaempferol promoted reactive oxygen species (ROS) evaluated using flow cytometric assay in HUVECs. We further investigated the upstream extrinsic pathway and showed that kaempferol stimulated death receptor signals [Fas/CD95, death receptor 4 (DR4) and DR5] through increasing the levels of phosphorylated p53 and phosphorylated ATM pathways in HUVECs, which can be individually confirmed by N-acetylcysteine (NAC), ATM specific inhibitor (caffeine) and p53 siRNA. Based on these results, kaempferol-induced HUVEC apoptosis was involved in an ROS-mediated p53/ATM/death receptor signaling. Kaempferol might possess therapeutic effects on cancer treatment in anti-vascular targeting.
authors.affiliation: Kaohsiung Veterans General Hospital Pingtung Branch, Pingtung, Taiwan, R.O.C.
authors.forename: Chiu-Fang
authors.initials: CF
authors.lastname: Lee
authors.affiliation: Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan, R.O.C.
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
authors.affiliation: Human Genetic Center, China Medical University Hospital, Taichung, Taiwan, R.O.C.
authors.forename: Fuu-Jen
authors.initials: FJ
authors.lastname: Tsai
authors.affiliation: Kaohsiung Veterans General Hospital Pingtung Branch, Pingtung, Taiwan, R.O.C.
authors.forename: Ni-Na
authors.initials: NN
authors.lastname: Chiang
authors.affiliation: School of Nutrition and Health Sciences, Taipei Medical University, Taipei, Taiwan, R.O.C.
authors.forename: Chi-Cheng
authors.initials: CC
authors.lastname: Lu
authors.affiliation: Department of Pharmacy and Master Program, Tajen University, Pingtung, Taiwan, R.O.C.
authors.forename: Yu-Syuan
authors.initials: YS
authors.lastname: Huang
authors.affiliation: Department of Pharmacy and Master Program, Tajen University, Pingtung, Taiwan, R.O.C.
authors.forename: Chun
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Pharmacy and Master Program, Tajen University, Pingtung, Taiwan, R.O.C.
authors.forename: Fu-An
authors.initials: FA
authors.lastname: Chen
mesh_terms: D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D044949:Kaempferols / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D044949:Kaempferols; D017382:Reactive Oxygen Species; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C006552:kaempferol; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins