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Published on: February 9, 2021
Cyclooxygenase inhibitors differentially modulate p73 isoforms in neuroblastoma
L M S Lau1, J K Wolter, J T M L Lau
1Hospital for Sick Children, University of Toronto, Ontario, Canada.
Oncogene
|April 14, 2009
Summary
Cyclooxygenase (COX) inhibitors promote cancer cell death by increasing proapoptotic TAp73 and decreasing antiapoptotic DeltaNp73 isoforms. These findings support COX inhibitors as potential cancer therapeutics, especially for tumors with deregulated E2F1.
Area of Science:
- Molecular Biology
- Oncology
- Pharmacology
Background:
- The p73 gene produces distinct isoforms: proapoptotic TAp73 and antiapoptotic DeltaNp73.
- DeltaNp73 proteins are overexpressed in tumors like neuroblastoma, inhibiting p53 and TAp73.
- Targeting p73 isoforms presents a therapeutic strategy for cancer treatment.
Purpose of the Study:
- To investigate the effect of cyclooxygenase (COX) inhibitors on p73 isoforms in cancer.
- To determine if COX inhibitors can be used to modulate p73 for enhanced apoptosis.
Main Methods:
- Treatment of neuroblastoma and other tumor cells with COX inhibitors.
- Analysis of endogenous p73 isoform expression (TAp73beta, DeltaNp73(AS)).
- Assessment of apoptosis induction and E2F1 activity.
- Studies involving forced expression of DeltaNp73(AS) isoforms.
Main Results:
- COX inhibitors induced apoptosis independently of p53, upregulating TAp73beta and its target genes.
- COX inhibitors downregulated alternative-spliced DeltaNp73(AS) isoforms (Deltaexon2, Deltaexon2/3).
- Overexpression of DeltaNp73(AS) reduced apoptosis induced by the COX-2 inhibitor celecoxib.
- Celecoxib decreased E2F1 levels, impacting p73 promoter activation.
Conclusions:
- COX inhibitors differentially modulate p73 isoforms, enhancing apoptosis in cancer cells.
- These findings suggest COX inhibitors as novel regulators of p73 for improved chemosensitivity.
- Potential application in tumors with deregulated E2F1 or wild-type/mutant p53.
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