[Correlation of intra-cellular localization and variations of active caspase-3 to morphology changes in apoptotic MOLT-4 cells induced by X-ray].
OBJECTIVE
How pro-caspase-3 activation lead to serial morphology changes during progress of cell apoptosis is unclear. This study was to investigate the variations and intra-localization of active Caspase-3, determine cell morphology changes in apoptotic MOLT-4 cells induced by X-ray, and evaluate their relationship.


METHODS
MOLT-4 cells were irradiated by 10 Gy X-ray. Sub G(1)peak method, and DNA fragmentation assay were used to detect variations of DNA in apoptotic cells. Annexin V/PI method was used to determine the cell membrane reversion, and fluorescence labeled inhibitor of Caspases (FLICA) was used to detect the active Caspase-3 in apoptotic cells. Cell morphology and Caspase-3 intra-localization were determined by confocal microscopy.


RESULTS
MOLT-4 cells irradiated by 10 Gy X-ray presented classical apoptotic morphology changes such as membrane reversion, and apoptotic body. Caspase-3 was activated after irradiation, and increased remarkably after irradiated for 4 hours. Activated Caspase-3 moved from sub-membrane toward cytoplasm and nucleus. Caspase-3 activity was detected 2 hours earlier than membrane reversion.


CONCLUSIONS
Caspase-3 was activated in MOLT-4 cells induced by X-ray, and its intra-localization correlated with the apoptotic morphology changes. The spatial shift of active Caspase-3 in MOLT-4 cells induced by X-ray is one of the mechanisms of apoptosis.
Feng
Yong-Dong
YD
Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030 PR China.
Xie
Da-Xing
DX
Qin
Ji-Chao
JC
Zhong
Yi-Sheng
YS
Li
Xiao-Lan
XL
Xiao
Wei
W
Wu
Jian-Hong
JH
Tao
De-Ding
DD
Hu
Jun-Bo
JB
Gong
Jian-Ping
JP
D017209:Apoptosis / Q000528:radiation effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000201:enzymology; D003593:Cytoplasm / Q000201:enzymology; D053938:DNA Fragmentation; D004789:Enzyme Activation / Q000528:radiation effects; D005434:Flow Cytometry; D006801:Humans; D015458:Leukemia, T-Cell / Q000201:enzymology / Q000473:pathology*; D018613:Microscopy, Confocal
C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases