Overexpression of caspase-9 triggers its activation and apoptosis in vitro.
OBJECTIVE
To investigate the consequences of increased expression of caspase-9: 1) whether the caspase-9 overexpression resulted in cell death through apoptosis, 2) whether apoptosis could be triggered in normal and tumor cells, and 3) what is the role of caspase-9 in the process.


METHODS
The caspase-9 fused to green fluorescent protein was expressed in primary cultures of anterior pituitary cells and of HeLa tumor cells. The expressed caspase-9 and the number of apoptotic and necrotic cells were determined using fluorescence microscopy.


RESULTS
Overexpression of caspase-9 resulted in cell death of primary pituitary cells and HeLa cells. More than 94% of the cells died of apoptosis, which was triggered by the activation of caspase-9, since the cell deaths were prevented in the presence of caspase-9 specific inhibitor. HeLa cells were about 50% more resistant to apoptosis than pituitary cells.


CONCLUSIONS
Caspase-9 overexpression and its activation leads to apoptosis. It occurs both in normal and tumor cells. Since the majority of cancer therapy treatments initiate apoptosis through the caspase-9 activation, the modulation of caspase-9 expression may be exploited in designing new ways to control apoptosis in neurodegenerative or malignant diseases.
Druskovic
Mirjam
M
Institute of Pathophysiology, Medical Faculty, Ljubljana, Slovenia.
Suput
Dusan
D
Milisav
Irina
I
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053453:Caspase 9 / Q000096:biosynthesis*; D004789:Enzyme Activation; D006367:HeLa Cells / Q000187:drug effects; D006801:Humans; D008297:Male; D010902:Pituitary Gland / Q000166:cytology / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D053453:Caspase 9