title: Safrole induces G0/G1 phase arrest via inhibition of cyclin E and provokes apoptosis through endoplasmic reticulum stress and mitochondrion-dependent pathways in human leukemia HL-60 cells.
abstract: Safrole, a component of Piper betle inflorescence, is a carcinogen which has been demonstrated to induce apoptosis on human oral cancer HSC-3 cells in vitro and to inhibit HSC-3 cells in xenograft tumor cells in vivo. In our previous study, safrole promoted phagocytosis by macrophages and natural killer cell cytotoxicity in normal BALB/c mice. The cytotoxic effects of safrole on HL-60 cells were investigated by using flow cytometric analysis, comet assay, 4',6-diamidino-2-phenylindole (DAPI) staining, western blotting and confocal laser microscopy. The obtained results indicate that safrole induced a cytotoxic response through reducing the percentage of viable cells and induction of apoptosis in HL-60 cells in a dose-dependent manner. DAPI staining and comet assay also showed that safrole induced apoptosis (chromatin condensation) and DNA damage in HL-60 cells. The flow cytometric assay showed that safrole increased the production of reactive oxygen species (ROS) and Ca(2+) and reduced the mitochondrial membrane potential in HL-60 cells. Safrole enhanced the levels of the pro-apoptotic protein BAX, inhibited those of the anti-apoptotic protein BCL-2 and promoted the levels of apoptosis-inducing factor (AIF) and endonuclease G (Endo G) in HL-60 cells. Furthermore, safrole promoted the expression of glucose-regulated protein 78 (GRP78), growth arrest- and DNA damage-inducible gene 153 (GADD153) and of activating transcription factor 6α (ATF-6α). Based on these findings, we suggest that safrole-induced apoptosis in HL-60 cells is mediated through the ER stress and intrinsic signaling pathways.
authors.affiliation: School of Pharmacy, China Medical University, Taichung, Taiwan, ROC.
authors.forename: Chun-Shu
authors.initials: CS
authors.lastname: Yu
authors.forename: An-Cheng
authors.initials: AC
authors.lastname: Huang
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
authors.forename: Chien-Chih
authors.initials: CC
authors.lastname: Yu
authors.forename: Chin-Chung
authors.initials: CC
authors.lastname: Lin
authors.forename: Hsiung-Kwang
authors.initials: HK
authors.lastname: Chung
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Huang
authors.forename: Fu-Shin
authors.initials: FS
authors.lastname: Chueh
authors.forename: Jing-Gung
authors.initials: JG
authors.lastname: Chung
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects*; D019927:Cyclin E / Q000037:antagonists & inhibitors*; D004249:DNA Damage; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D016193:G1 Phase / Q000187:drug effects; D018922:HL-60 Cells; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008928:Mitochondria / Q000502:physiology*; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D012451:Safrole / Q000494:pharmacology*; D051742:Transcription Factor CHOP / Q000378:metabolism
chemical_list: D051033:Apoptosis Inducing Factor; D019927:Cyclin E; C497249:DDIT3 protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; C000717248:Hspa5 protein, mouse; D051742:Transcription Factor CHOP; D012451:Safrole; D002118:Calcium