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E1A signaling to p53 involves the p19(ARF) tumor suppressor
E de Stanchina1, M E McCurrach, F Zindy
1Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724 USA.
Abstract:
The adenovirus E1A oncogene activates p53 through a signaling pathway involving the retinoblastoma protein and the tumor suppressor p19(ARF). The ability of E1A to induce p53 and its transcriptional targets is severely compromised in ARF-null cells, which remain resistant to apoptosis following serum depletion or adriamycin treatment. Reintroduction of p19(ARF) restores p53 accumulation and resensitizes ARF-null cells to apoptotic signals. Therefore, p19(ARF) functions as part of a p53-dependent failsafe mechanism to counter uncontrolled proliferation. Synergistic effects between the p19(ARF) and DNA damage pathways in inducing p53 may contribute to E1A's ability to enhance radio- and chemosensitivity.
Insights
Adenovirus E1A oncogene activates p53 via the retinoblastoma protein and p19ARF tumor suppressor. Restoring p19ARF in ARF-null cells re-sensitizes them to apoptosis, highlighting its role in preventing uncontrolled cell growth.
Area of Science:
- Oncogene research
- Tumor suppressor mechanisms
- Cellular apoptosis pathways
Background:
- The adenovirus E1A oncogene is known to activate the p53 tumor suppressor.
- This activation involves a signaling pathway including the retinoblastoma protein and the p19ARF tumor suppressor.
Purpose of the Study:
- To investigate the role of p19ARF in the E1A-mediated activation of p53.
- To determine if p19ARF is essential for E1A-induced apoptosis and sensitivity to genotoxic stress.
Main Methods:
- Experiments were conducted using ARF-null cells to assess the impact of p19ARF deficiency.
- Reintroduction of p19ARF into these cells was performed to evaluate its functional restoration.
- Cells were subjected to serum depletion and adriamycin treatment to induce apoptosis.
Main Results:
- E1A's ability to induce p53 and its targets was significantly impaired in ARF-null cells.
- ARF-null cells showed resistance to apoptosis induced by serum depletion or adriamycin.
- Reintroducing p19ARF restored p53 accumulation and re-sensitized cells to apoptotic stimuli.
Conclusions:
- p19ARF acts as a critical component of a p53-dependent failsafe mechanism against uncontrolled proliferation.
- The interplay between p19ARF and DNA damage pathways may explain E1A's enhancement of radio- and chemosensitivity.