hAda3 regulates p14ARF-induced p53 acetylation and senescence
P Sekaric1, V A Shamanin, J Luo
1Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Oncogene
|April 25, 2007
Summary
p14ARF induces cell senescence by promoting p53 acetylation, a process dependent on hAda3. This pathway is crucial for activating tumor suppressor p53 in human mammary epithelial cells.
Area of Science:
- Cellular senescence
- Tumor suppressor pathways
- Epigenetic regulation
Background:
- p53 acetylation is critical for its activation.
- p14ARF is known to inhibit p53 degradation by Mdm2.
- The role of histone acetyltransferase complexes in p14ARF-mediated senescence is not fully understood.
Purpose of the Study:
- To investigate the role of hAda3 in p14ARF-induced senescence.
- To elucidate the mechanism by which p14ARF regulates p53 acetylation.
- To determine the functional significance of hAda3 in p53 activation and cell cycle control.
Main Methods:
- Utilized human mammary epithelial cells (MEC) and H1299 cell lines.
- Employed p14ARF induction and expression of hAda3 domains.
- Utilized small interfering RNA (siRNA) for hAda3 depletion.
- Assessed p53 acetylation, p21cip1 accumulation, and cellular senescence.
Main Results:
- p14ARF-induced senescence in MECs correlates with p53 acetylation and requires hAda3.
- Blocking hAda3 interaction with p53 inhibits p53 acetylation and senescence.
- HPV16 E6 mutant Y54D, targeting hAda3, reduces p53 acetylation and protects MECs from senescence.
- hAda3 overexpression enhances p300-mediated p53 acetylation; hAda3 depletion inhibits it.
- hAda3 depletion reduces endogenous p53 acetylation and p21cip1 induction upon p14ARF expression.
Conclusions:
- p14ARF utilizes hAda3 to stimulate p53 acetylation, leading to cell senescence.
- hAda3 acts as a crucial coactivator for p53 acetylation in response to p14ARF.
- This pathway represents a novel mechanism for p53 activation and tumor suppression.
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