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Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
Of the many cellular responses activated by TP53, which ones are critical for tumour suppression?
Annabella F Thomas1,2, Gemma L Kelly1,2, Andreas Strasser3,4
1The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.
Abstract:
The tumour suppressor TP53 is a master regulator of several cellular processes that collectively suppress tumorigenesis. The TP53 gene is mutated in ~50% of human cancers and these defects usually confer poor responses to therapy. The TP53 protein functions as a homo-tetrameric transcription factor, directly regulating the expression of ~500 target genes, some of them involved in cell death, cell cycling, cell senescence, DNA repair and metabolism. Originally, it was thought that the induction of apoptotic cell death was the principal mechanism by which TP53 prevents the development of tumours. However, gene targeted mice lacking the critical effectors of TP53-induced apoptosis (PUMA and NOXA) do not spontaneously develop tumours. Indeed, even mice lacking the critical mediators for TP53-induced apoptosis, G1/S cell cycle arrest and cell senescence, namely PUMA, NOXA and p21, do not spontaneously develop tumours. This suggests that TP53 must activate additional cellular responses to mediate tumour suppression. In this review, we will discuss the processes by which TP53 regulates cell death, cell cycling/cell senescence, DNA damage repair and metabolic adaptation, and place this in context of current understanding of TP53-mediated tumour suppression.
Insights
The tumor suppressor TP53 (tumor protein 53) regulates multiple cellular processes to prevent cancer. Its functions extend beyond apoptosis to include cell cycle control, DNA repair, and metabolism for tumor suppression.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- The tumor suppressor TP53 is a critical regulator of cellular processes that prevent tumorigenesis.
- TP53 gene mutations are found in approximately 50% of human cancers, often correlating with poor therapeutic outcomes.
- TP53 protein acts as a transcription factor, regulating hundreds of target genes involved in cell death, cell cycle, senescence, DNA repair, and metabolism.
Purpose of the Study:
- To review the multifaceted roles of TP53 in tumor suppression.
- To explore how TP53 regulates cell death, cell cycling, senescence, DNA repair, and metabolic adaptation.
- To contextualize these functions within the broader understanding of TP53-mediated tumor suppression.
Main Methods:
- Literature review of studies on TP53 function and tumor suppression.
- Analysis of gene-targeted mouse models lacking key TP53 effectors.
- Synthesis of current research on TP53's regulatory mechanisms.
Main Results:
- Evidence suggests TP53-mediated tumor suppression involves more than just apoptosis.
- Mice lacking TP53-induced apoptosis effectors (PUMA, NOXA) or cell cycle/senescence mediators (PUMA, NOXA, p21) do not spontaneously develop tumors.
- TP53 regulates diverse cellular processes critical for preventing cancer development.
Conclusions:
- TP53's tumor suppressor role is mediated by a complex network of cellular responses.
- Understanding these diverse mechanisms is crucial for developing effective cancer therapies targeting TP53.
- TP53's regulation of cell death, cell cycle, DNA repair, and metabolism are all vital for its tumor suppressor function.
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