The p53 tumour suppressor is the most frequently mutated gene in human cancer.This transcription factor can be activated by diverse cellular stresses, including DNA damage and oncogene activation.Through transcriptional induction of appropriate target genes, p53 can stimulate activity in a broad range of effector pathways, most notably cell cycle arrest, cellular senescence and apoptotic teal horse blanket cell death.
Insensitivity to cell death-inducing signals and deregulated proliferation are two key hallmarks of cancer cells.Given that p53 inhibits proliferation and induces apoptosis, it was widely believed that these processes are the most critical ones for p53-mediated tumour suppression.However, this dogma has been challenged.
In striking contrast to p53-deficient mice, which all develop tumours before 250 days of age, mutant mice in which expression of the p53 target genes that are critical for induction of cell cycle arrest and apoptosis is impaired or abrogated are not cancer-prone.This demonstrates that distinct effector processes are critical for the p53-mediated acute response to DNA read more damage versus p53-mediated tumour suppression.The discovery that cell cycle arrest, senescence and apoptosis are not essential for p53-mediated tumour suppression re-launches the search for the p53 target genes and effector processes that are critical to prevent tumour development, with coordination of DNA repair being a leading contender.