title: The role of Ca2+ in baicalein-induced apoptosis in human breast MDA-MB-231 cancer cells through mitochondria- and caspase-3-dependent pathway.
abstract: Baicalein was investigated for tumor cell-specific cytotoxicity, apoptosis-inducing activity and signal pathway against the MDA-MB-231 human breast cancer cell line. After the MDA-MB-231 cells had been treated with baicalein, trypan blue exclusion, propidium iodide (PI) assay and 4',6-diamidino-2-phenylindole (DAPI) were used to stain the dead cells and detect apoptosis, respectively. The effects of baicalein on the levels of reactive oxygen species (ROS), Ca2+ and mitochondrial membrane potential (deltapsim) on MDA-MB-231 cells were examined by flow cytometric assays. The ROS caused endoplasmic reticulum (ER) stress, confirmed by the increase of GADD153 and GRP78 in the examined cells. GADD153 and GRP78 increases were also confirmed by confocal laser microscopy examination and indicated that both proteins translocated to the nucleus. The effects of baicalein on the expression of apoptotic-regulated genes, such as Bcl-2 family and caspase, were detected by Western blotting. To further investigate the apoptotic pathway and the role of Ca2+ induced by baicalein, a caspase-3 inhibitor and Ca2+ chelator were used to block caspase-3 activity and Ca2+ in MDA-MB-231 cells. Baicalein induced apoptosis in a time-dependent effect through the inhibition of Bcl-2 expression, increased the levels of Bax, reduced the level of deltapsim, and promoted the cytochrome c release and caspase-3 activation. MDA-MB-231 cells were pretreated with BAPTA which reduced the levels of Ca2+, deltapsim and apoptosis. In conclusion, baicalein induced apoptosis via Ca2+ production, mitochondria-dependent and caspase-3 activation in MDA-MB-231 cells.
authors.affiliation: Department of Surgery, China Medical University Hospital, Taichung, Taiwan, ROC.
authors.forename: Jau-Hong
authors.initials: JH
authors.lastname: Lee
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Li
authors.forename: Siu-Wan
authors.initials: SW
authors.lastname: Ip
authors.forename: Shu-Chun
authors.initials: SC
authors.lastname: Hsu
authors.forename: Nai-Wen
authors.initials: NW
authors.lastname: Chang
authors.forename: Nou-Ying
authors.initials: NY
authors.lastname: Tang
authors.forename: Chun-Shu
authors.initials: CS
authors.lastname: Yu
authors.forename: Su-Tze
authors.initials: ST
authors.lastname: Chou
authors.forename: Song-Shei
authors.initials: SS
authors.lastname: Lin
authors.forename: Chin-Chung
authors.initials: CC
authors.lastname: Lino
authors.forename: Jai-Sing
authors.initials: JS
authors.lastname: Yang
authors.forename: Jing-Gung
authors.initials: JG
authors.lastname: Chung
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000517:prevention & control; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism*; D045744:Cell Line, Tumor; D045304:Cytochromes c / Q000096:biosynthesis; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000091342:Endoplasmic Reticulum Chaperone BiP; D044950:Flavanones / Q000494:pharmacology*; D005434:Flow Cytometry; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D018832:Molecular Chaperones / Q000096:biosynthesis; D009842:Oligopeptides / Q000494:pharmacology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D051742:Transcription Factor CHOP / Q000096:biosynthesis / Q000235:genetics; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis
chemical_list: C494826:BAX protein, human; C497249:DDIT3 protein, human; D000091342:Endoplasmic Reticulum Chaperone BiP; D044950:Flavanones; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009842:Oligopeptides; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; D051028:bcl-2-Associated X Protein; D051742:Transcription Factor CHOP; C006680:baicalein; D004533:Egtazic Acid; D045304:Cytochromes c; D053148:Caspase 3; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium