Dual effect of p53 on radiation sensitivity in vivo: p53 promotes hematopoietic injury, but protects from gastro-intestinal syndrome in mice

EA Komarova, RV Kondratov, K Wang, K Christov… - Oncogene, 2004 - nature.com
EA Komarova, RV Kondratov, K Wang, K Christov, TV Golovkina, JR Goldblum, AV Gudkov
Oncogene, 2004nature.com
Ionizing radiation (IR) induces p53-dependent apoptosis in radiosensitive tissues,
suggesting that p53 is a determinant of radiation syndromes. In fact, p53-deficient mice
survive doses of IR that cause lethal hematopoietic syndrome in wild-type animals.
Surprisingly, p53 deficiency results in sensitization of mice to higher doses of IR, causing
lethal gastro-intestinal (GI) syndrome. While cells in the crypts of p53-wild-type epithelium
undergo prolonged growth arrest after irradiation, continuous cell proliferation ongoing in …
Abstract
Ionizing radiation (IR) induces p53-dependent apoptosis in radiosensitive tissues, suggesting that p53 is a determinant of radiation syndromes. In fact, p53-deficient mice survive doses of IR that cause lethal hematopoietic syndrome in wild-type animals. Surprisingly, p53 deficiency results in sensitization of mice to higher doses of IR, causing lethal gastro-intestinal (GI) syndrome. While cells in the crypts of p53-wild-type epithelium undergo prolonged growth arrest after irradiation, continuous cell proliferation ongoing in p53-deficient epithelium correlates with accelerated death of damaged cells followed by rapid destruction of villi and accelerated lethality. p21-deficient mice are also characterized by increased sensitivity to GI syndrome-inducing doses of IR. We conclude that p53/p21-mediated growth arrest plays a protective role in the epithelium of small intestine after severe doses of IR. Pharmacological inhibition of p53 by a small molecule that can rescue from lethal hematopoietic syndrome has no effect on the lethality from gastro-intestinal syndrome, presumably because of a temporary and reversible nature of its action.
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