title: Anticancer effects of imperatorin isolated from Angelica dahurica: induction of apoptosis in HepG2 cells through both death-receptor- and mitochondria-mediated pathways.
abstract: BACKGROUND
  Imperatorin (IM) is a furanocoumarin isolated from the root of Angelica dahurica, which is reported to have anticonvulsant and anticancer effects. In this study, the antiproliferative effect of IM on 9 human cancer cell lines was examined, and human hepatoma HepG2 cells were chosen as the target for preferential killing by IM. Particularly, the mechanism of IM-induced apoptosis and in vivo animal effects were also studied.
  
  
  METHODS
  Cell viability was measured using MTT assay, and apoptosis was detected by Hoechst staining, annexin V-PI staining, and DNA laddering assay. Mitochondrial membrane potential was detected by JC-1 staining. Western blot analysis was employed to detect the expression of apoptosis-related proteins. In addition, the in vivo anticancer effect of IM was examined in nude mice bearing HepG2 cells.
  
  
  RESULTS
  IM inhibited the proliferation of HepG2 cells through apoptosis induction in a time- and dose-dependent manner by observation of the nuclear morphology, DNA fragmentation, phosphatidylserine externalization, loss of mitochondrial membrane potential, release of cytochrome c into cytosol, and activation of caspase-3, caspase-8, caspase-9, and poly(ADP-ribose) polymerase cleavage. As cell death could partly be prevented by the caspase-8 or caspase-9 inhibitor and was evidenced by the results of Western blot analysis, our results also suggest that IM-induced apoptosis is mediated through both death receptor and mitochondrial pathways. In the animal model, IM was found to effectively suppress tumor growth by 31.93 and 63.18% at dosages of 50 and 100 mg/kg, respectively, after treatment for 14 days. No significant weight loss or toxicity to the hosts was found.
  
  
  CONCLUSIONS
  IM can function as a cancer suppressor by inducing apoptosis in HepG2 cells through both death-receptor- and mitochondria-mediated pathways. Furthermore, the in vivo antitumor activities of IM are significant with negligible weight loss and damage to the host.
authors.affiliation: Research Center of Siyuan Natural Pharmacy and Biotoxicology, College of Life Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Ke-wang
authors.initials: KW
authors.lastname: Luo
authors.forename: Jian-guo
authors.initials: JG
authors.lastname: Sun
authors.forename: Judy Yuet-Wa
authors.initials: JY
authors.lastname: Chan
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.forename: Shi-hua
authors.initials: SH
authors.lastname: Wu
authors.forename: Kwok-Pui
authors.initials: KP
authors.lastname: Fung
authors.forename: Fei-yan
authors.initials: FY
authors.lastname: Liu
mesh_terms: D029969:Angelica; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D011564:Furocoumarins / Q000302:isolation & purification / Q000502:physiology*; D018922:HL-60 Cells; D019073:HT29 Cells; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008928:Mitochondria / Q000187:drug effects / Q000502:physiology*; D018517:Plant Roots; D053218:Receptors, Death Domain / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D023041:Xenograft Model Antitumor Assays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D011564:Furocoumarins; D053218:Receptors, Death Domain; C031534:imperatorin