p53 protein regulates the effects of amifostine on apoptosis, cell cycle progression, and cytoprotection

• Published in: British journal of cancer Vol. 88; no. 5; pp. 754 - 759
• Main Authors: LEE, E. J, GERHOLD, M, PALMER, M. W, CHRISTEN, R. D
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 10.03.2003
• Subjects: Amifostine - pharmacology; Apoptosis; Apoptosis - drug effects; Apoptosis - physiology; Biological and medical sciences; Blotting, Western; Cancer research; Cancer therapies; Cell cycle; Cell Cycle - drug effects; Cell Cycle - physiology; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-dependent kinases; Cyclins - metabolism; Cytoprotection; Cytotoxicity; Experimental Therapeutics; Free radicals; Head & neck cancer; Humans; Kinases; Medical research; Medical sciences; Miscellaneous; Pharmacology. Drug treatments; Proteins; Radiation therapy; Tumor Cells, Cultured; Tumor Suppressor Protein p53 - metabolism; Tumor Suppressor Protein p53 - physiology; Human; Carcinoma; cytoprotection; Malignant tumor; p21 protein; cell cycle arrest; Amifostine; Biological activity; p53 protein; Colonic disease; Regulation(control); TP53 Gene; Shutdown; Cytoprotector; Cell death; Cell cycle; Established cell line; Digestive diseases; Genetics; Intestinal disease; Colon; Apoptosis; Tumor suppressor gene
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/sj.bjc.6600779

To determine the role of p53 protein on the cellular effects of amifostine, we used molecularly engineered HCT116 colon cancer cells in which the p53 gene was inactivated by targeted homologous recombination or p53 protein was degraded by high-level expression of papillomavirus E6 protein. Amifostine induced a G1 arrest and protected against paclitaxel toxicity in p53-proficient but not in p53-deficient cells. In the absence of p53 protein, amifostine enhanced the cytotoxicity of paclitaxel. In addition, treatment of HCT116 cells with amifostine alone resulted in apoptotic cell death. Compared with p53-deficient cells, p53-proficient cells exhibited low-level resistance to amifostine-induced apoptosis. Amifostine induced the expression of p53 protein in p53-proficient cells and the expression of p21 protein in both p53-proficient and -deficient cells. These findings indicate that amifostine-induced G1 arrest and cytoprotection are mediated via a pathway that is dependent on p53 protein and that amifostine-induced expression of p21 protein is not sufficient to sustain a G1 arrest or to mediate cytoprotection. In addition, these findings identify p53 protein as a mechanism of resistance to amifostine-induced apoptosis.British