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Induction and Testing of Hypoxia in Cell Culture
Published on: August 12, 2011
Hypoxia induces p53-dependent transactivation and Fas/CD95-dependent apoptosis
T Liu1, C Laurell, G Selivanova
1Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institute, Stockholm, Sweden.
Cell Death and Differentiation
|August 19, 2006
Summary
Hypoxia induces p53 protein and apoptosis in colon cancer cells. Fas/CD95 is key for this p53-dependent cell death, revealing a unique stress response pathway.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- The tumor suppressor p53 plays a crucial role in cellular stress response, primarily by inducing apoptosis.
- Understanding p53's role in response to specific stressors like hypoxia is vital for cancer therapy.
- Colon carcinoma cells (HCT116) with and without p53 were used to dissect p53's function.
Purpose of the Study:
- To investigate p53-dependent gene and protein expression changes under hypoxic conditions.
- To identify novel p53 target genes involved in hypoxia-induced apoptosis.
- To elucidate the role of Fas/CD95 signaling in p53-mediated apoptosis during hypoxia.
Main Methods:
- Utilized wild-type and p53-null HCT116 colon carcinoma cell lines.
- Analyzed p53 protein levels and apoptosis induction under hypoxia.
- Performed cDNA microarray analysis to assess gene expression changes.
- Investigated the effect of blocking Fas/CD95 signaling and inhibiting caspase 8.
Main Results:
- Hypoxia increased p53 protein levels and induced p53-dependent apoptosis in HCT116 cells.
- Only a limited set of genes, distinct from classical p53 targets, were regulated by p53 under hypoxia.
- Fas/CD95, ANXA1, DDIT3/GADD153 (CHOP), SEL1L, and SMURF1 were identified as significantly induced p53 target genes.
- Blocking Fas/CD95 signaling or caspase 8 inhibited hypoxia-induced apoptosis.
Conclusions:
- Hypoxia elicits a unique p53-dependent gene expression profile compared to other cellular stresses.
- Fas/CD95 is a critical mediator of p53-dependent apoptosis induced by hypoxia.
- Targeting the p53-Fas/CD95 axis may offer therapeutic strategies for hypoxic tumors.
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