Apigenin induces caspase-dependent apoptosis in human lung cancer A549 cells through Bax- and Bcl-2-triggered mitochondrial pathway.
The molecular mechanism and possible signaling pathway of apigenin-induced cytotoxicity and apoptosis in human lung cancer cells has not been reported. We investigated the role of ROS, Ca2+, caspases and Bax proteins and mitochondria membrane potential in apigenin-induced apoptosis in A549 cells. Cells were incubated with different concentrations of apigenin then cell morphological changes, DNA damage, cell viability and apoptosis were determined by Comet assay, and flow cytometric analysis. Sub-G1 phase was also examined. Western blot analysis was used to determined the levels of Bax and Bcl-2 and apoptosis associated proteins, and confocal laser microscope for examining the translocation of associated protein after exposed to apigenin. The results indicated that apigenin induced morphological changes, decreased percentage of viable cells and induced apoptosis dose- and time-dependently. DAPI staining and Comet assay also confirmed that apigenin-induced DNA condensation and damage. The levels of caspase-3, -8 and -9 involved in apigenin-induced apoptosis indicating caspase-dependent pathway was induced by apigenin. Western blotting showed that apigenin promoted cytochrome c levels and also induced dysfunction of mitochondria leading to the release of cytochrome c, AIF and Endo G, causing the activation of caspase-9 and -3, then apoptosis in A549 cells.
Lu
Hsu-Feng
HF
Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei 112, Taiwan, R.O.C.
Chie
Yu-Jie
YJ
Yang
Ming-Sung
MS
Lee
Ching-Sung
CS
Fu
Jene-John
JJ
Yang
Jai-Sing
JS
Tan
Tzu-Wei
TW
Wu
Shin-Hwar
SH
Ma
Yi-Shih
YS
Ip
Siu-Wan
SW
Chung
Jing-Gung
JG
D000970:Antineoplastic Agents / Q000494:pharmacology*; D047310:Apigenin / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020169:Caspases / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D051028:bcl-2-Associated X Protein / Q000187:drug effects
D000970:Antineoplastic Agents; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D047310:Apigenin; D020169:Caspases