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07:42
Activation of Apoptosis by Cytoplasmic Microinjection of Cytochrome c
Published on: June 29, 2011
Early events in Bcl-2-enhanced apoptosis
1Pediatric Center for Neuroscience and Division of Child Neurology, Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA 15213, USA.
Apoptosis : an International Journal on Programmed Cell Death
|January 24, 2004
Summary
Overexpressing Bcl-2 in PC12 cells enhances apoptosis from neocarzinostatin (NCS). This potentiation occurs before Bcl-2 cleavage, involving mitochondrial Bax translocation and cytochrome C release.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Bcl-2 is an anti-apoptotic protein.
- Neocarzinostatin (NCS) is an antimitotic agent that induces apoptosis.
- The role of Bcl-2 in modulating NCS-induced apoptosis is not fully understood.
Purpose of the Study:
- To investigate the mechanism by which Bcl-2 potentiates NCS-induced apoptosis in PC12 cells.
- To identify the cellular events preceding caspase 3 activation in this system.
Main Methods:
- PC12 cells were transfected with Bcl-2 or a mock vector.
- Cells were treated with NCS.
- Mitochondrial Bax translocation, cytochrome C release, mitochondrial membrane potential, and caspase activation were assessed.
Main Results:
- NCS treatment induced Bax translocation to mitochondria and cytochrome C release in both mock- and Bcl-2-transfected cells.
- Mitochondrial membrane potential decreased immediately in Bcl-2-transfected cells, unlike mock-transfected cells.
- Caspase 9 activation was enhanced and prolonged in Bcl-2-transfected cells.
- Bcl-2 cleavage occurred late, after initial apoptotic events.
Conclusions:
- Bcl-2 potentiation of NCS-induced apoptosis involves early mitochondrial events preceding Bcl-2 cleavage.
- Mitochondrial membrane potential drop and cytochrome C release occur despite intact mitochondrial Bcl-2.
- Bcl-2 cleavage is not the sole factor responsible for potentiating NCS-induced apoptosis.
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