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p53, apoptosis and human cancers
1Department of Obstetrics and Gynecology, University of Tennessee Medical Center at Knoxville, USA.
Abstract:
More than half of human cancers contain p53 mutations. Structural analyses of p53-DNA interactions indicate that hot spots of p53 mutation are often either involved in direct contact with target DNA or those that maintain specific conformation of p53. One significant consequence of the loss of wild type p53 function is inhibition of apoptosis, which may be through the inability of mutant p53 to transcriptionally activate bax gene expression. Quantitative correlation among ultraviolet-induced p53 mutations of keratocytes, inhibition of apoptosis and the development of squamous cell cancer of the skin further suggest a central role of inhibited apoptosis between p53 mutations and tumorigenesis. Hypoxia-mediated selection for p53 mutant cells with diminished apoptotic potential in solid tumors may account for the high prevalence of p53 mutations in human cancers. Our increasing understanding of the role of p53 mutations and apoptosis in human cancers has also provided some insights into strategies for anticancer therapy. Studies reconstituting the wild-type p53 through gene therapy have been encouraging. More importantly, further elucidation of the mechanisms of therapy-induced p53-independent apoptosis in cancer cells will facilitate the development of more efficient, less toxic anticancer therapy.
Insights
Mutations in the p53 tumor suppressor gene are common in human cancers, often inhibiting apoptosis and promoting tumor growth. Targeting apoptosis pathways offers promising anticancer therapy strategies.
Area of Science:
- Molecular Biology
- Cancer Research
- Genetics
Background:
- Over 50% of human cancers exhibit mutations in the p53 gene.
- p53 mutations frequently occur at DNA contact sites or regions critical for protein conformation.
- Loss of wild-type p53 function leads to apoptosis inhibition, potentially via impaired bax gene activation.
Purpose of the Study:
- To investigate the role of p53 mutations and apoptosis inhibition in human cancer development.
- To explore the link between p53 mutations, apoptosis, and tumorigenesis.
- To identify therapeutic strategies based on p53 function and apoptosis.
Main Methods:
- Structural analysis of p53-DNA interactions.
- Correlation studies of UV-induced p53 mutations, apoptosis inhibition, and skin cancer.
- Investigation of hypoxia-mediated selection in solid tumors.
- Gene therapy approaches to restore wild-type p53 function.
Main Results:
- p53 mutation 'hot spots' are often involved in direct DNA binding or maintaining p53 conformation.
- UV-induced p53 mutations in keratocytes correlate with apoptosis inhibition and skin cancer.
- Hypoxia may select for p53 mutant cells with reduced apoptosis, explaining high mutation prevalence.
- Gene therapy restoring wild-type p53 shows encouraging results.
Conclusions:
- Inhibited apoptosis is a key mechanism linking p53 mutations to tumorigenesis.
- Understanding p53's role in apoptosis informs novel anticancer therapies.
- Developing p53-independent apoptosis induction strategies is crucial for effective cancer treatment.