The Role of Ca2+ in Baicalein-induced Apoptosis in Human Breast MDA-MB-231 Cancer Cells through Mitochondria- and Caspase-3-dependent Pathway
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 4â²,6-diamidino-2-...
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Veröffentlicht in: | Anticancer research 2008-05, Vol.28 (3A), p.1701-1711 |
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Sprache: | eng |
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Zusammenfassung: | 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 4â²,6-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), Ca 2+ and mitochondrial membrane potential (ÎΨ m ) 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 Ca 2+ induced by baicalein, a caspase-3 inhibitor and Ca 2+ chelator were used to block caspase-3 activity and Ca 2+ 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 ÎΨ m , and promoted the cytochrome c release and caspase-3 activation. MDA-MB- 231 cells were pretreated with BAPTA which reduced
the levels of Ca 2+ , ÎΨ m and apoptosis. In conclusion, baicalein induced apoptosis via Ca 2+ production, mitochondria-dependent and caspase-3 activation in MDA-MB-231 cells. |
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ISSN: | 0250-7005 1791-7530 |