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Effects of cIAP-1, cIAP-2 and XIAP triple knockdown on prostate cancer cell susceptibility to apoptosis, cell survival and proliferation.
Gill, Catherine Dowling, Catherine O'Neill, Amanda J Watson, R William G
Gill, Catherine
Dowling, Catherine
O'Neill, Amanda J
Watson, R William G
Advisors
Editors
Other Contributors
Date
2009
Date Submitted
Keywords
Other Subjects
Subject Mesh
Apoptosis
Cell Line, Tumor
Cell Proliferation
Cell Survival
Data Interpretation, Statistical
Etoposide
Gene Expression
Gene Knockdown Techniques
Humans
Inhibitor of Apoptosis Proteins
Male
Peptide Hydrolases
Prostatic Neoplasms
RNA, Small Interfering
TNF-Related Apoptosis-Inducing Ligand
Tunicamycin
X-Linked Inhibitor of Apoptosis Protein
Cell Line, Tumor
Cell Proliferation
Cell Survival
Data Interpretation, Statistical
Etoposide
Gene Expression
Gene Knockdown Techniques
Humans
Inhibitor of Apoptosis Proteins
Male
Peptide Hydrolases
Prostatic Neoplasms
RNA, Small Interfering
TNF-Related Apoptosis-Inducing Ligand
Tunicamycin
X-Linked Inhibitor of Apoptosis Protein
Planned Date
Start Date
Collaborators
Principal Investigators
Files
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19549337.pdf
Adobe PDF, 760.65 KB
Alternative Titles
Publisher
Abstract
BACKGROUND: Manipulating apoptotic resistance represents an important strategy for the treatment of hormone refractory prostate cancer. We hypothesised that the Inhibitor of Apoptosis (IAP) Proteins may be mediating this resistance and knockdown of cIAP-1, cIAP-2 and XIAP would increase sensitivity to apoptosis. METHODS: cIAP-1, cIAP-2 and XIAP where knocked down either individually or in combination using siRNA in androgen independent prostate cancer PC-3 cells as confirmed by real-time PCR and western blotting. Cells were then treated with TRAIL, Etoposide, or Tunicamycin, and apoptosis assessed by PI DNA staining. Apoptosis was confirmed with Annexin V labelling and measurement of PARP cleavage, and was inhibited using the pan-caspase inhibitor, zVAD.fmk. Clonogenic assays and assessment of ID-1 expression by western blotting were used to measure recovery and proliferation. RESULTS: PC-3 are resistant to TRAIL induced apoptosis and have elevated expression of cIAP-1, cIAP-2 and XIAP. Combined knockdown sensitised PC-3 to TRAIL induced apoptosis, but not to Etoposide or Tunicmycin, with corresponding increases in caspase activity and PARP cleavage which was inhibited by ZVAD.fmk. Triple knock down decreased proliferation which was confirmed by decreased ID-1 expression. CONCLUSION: Simultaneous knock down of the IAPs not only sensitised the PC-3 to TRAIL but also inhibited their proliferation rates and clonogenic survival. The inability to alter sensitivity to other triggers of apoptosis suggests that this effect is specific for death receptor pathways and knock down might facilitate immune-surveillance mechanisms to counter cancer progression and, in combination with therapeutic approaches using TRAIL, could represent an important treatment strategy.
Language
en
ISSN
1476-4598
eISSN
ISBN
DOI
10.1186/1476-4598-8-39
PMID
19549337