Abstract
The p53 tumour suppressor is stabilised following exposure to genotoxic agents, such as γ-radiation. Cell responses to p53 stabilisation include induction of apoptosis and/or cell cycle arrest. Several studies have suggested that γ-radiation stabilises p53 by blocking ubiquitin mediated proteolysis. Here we have compared the biological activities of p53 stabilized following exposure to γ-radiation or treatment with the proteosome inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (ALLN) in MCF7 cells with wild type p53. Stabilisation of p53 by ALLN was reversible and was not blocked by caffeine. Although ALLN was a more effective p53 stabilising agent than γ-radiation, ALLN was not as effective at inducing cell cycle arrest/apoptosis as γ-radiation. Although p53 stabilised by ALLN and γ-radiation were both able to bind DNA and activate transcription, ALLN did not increase expression of BAX, which is involved in p53-induced apoptosis. Therefore, p53 stabilised by different agents is not always biologically active to the same extent and additional alterations triggered by γ-radiation may enable p53 to activate a subset of critical target genes, such as BAX, which are required for p53 responses.
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References
Ko LJ, Prives C. p53: Puzzle and paradigm. Genes and Develop 1996; 10: 1054–1072.
El-Deiry W, Tokino T, Velculescu VE, et al. WAF1, a potential mediator of p53 tumour suppression. Cell 1993; 75: 817–825.
Miyashita T, Reed JC. Tumour suppressor p53 is a direct transcriptional activator of the human bax gene. Cell 1995; 80: 293–299.
Hollstein M, Sidransky D, Vogelstein B, Harris C. p53 mutations in human cancer. Science 1991; 253: 49–53.
Levine AJ. p53, the cellular gatekeeper for growth and division. Cell 1997; 88: 323–331.
Maki CG, Huibregtse JM, Howley PM. In vivo ubiquitination and proteasome-mediated degradation of p53. Cancer Res 1996; 56: 2649–2654.
Kubbutat MHG, Vousden KH. Proteolytic cleavage of human p53 by calpain: a potential regulator of protein stability. Mol Cell Biol 1997; 17: 460–468.
Pariat M, Carillo S, Molinari M, et al. Proteolysis by calpains: a possible contribution to degradation of p53. Mol Cell Biol 1997; 17: 2806–2815.
Fredersdorf S, Milne AW, Hall PA, Lu X. Characterisation of a panel of novel anti-p21Waf1/Cip1 monoclonal antibodies and immunochemical analysis of p21Waf1/Cip1 expression in normal human tissues. Am J Pathol 1996; 148: 825–835.
Fredersdorf S, Burns J, Milne AM, Packham G, Fallis L, al. e, Lu X. High level expression of p27kip1 and cyclin D1 in some proliferating breast tumour cells: inverse correlation with the degree of malignancy in human breast and colorectal cancers. Proc Nat Acad Sci USA 1997; 94: 6380–6385.
Lu X, Lane DP. Differential induction of transcriptionally active p53 following UV or ionising radiation: defects in chromosome instability syndromes? Cell 1993; 75: 765–778.
O'Connor DJ, Lam EW-F, Griffin S, et al. Physical and functional interactions between p53 and cell cycle co-operating transcription factors, E2F1 and DP1. EMBO 1995; 14: 6184–6192.
Hsieh J-K, Fredersdorf S, Kauzarides T, Martin K, Lu X. E2F1 induced apoptosis requires DNA binding but not transcriptional activity and is inhibited by the retinoblastoma protein through direct interaction. Genes & Develop 1997; 11: 1840–1852.
Hupp TR, Meek DW, Midgley CA, Lane DP. Regulation of the specific DNA binding function of p53. Cell 1992; 71: 875–886.
Kastan MB, Onyekwere O, Sidransky D, Vogelstein B, Craig RW. Participation of p53 protein in the cellular response to DNA damage. Cancer Res 1991; 51: 6304–6311.
Maki CG, Howley PM. Ubiquitination of p53 and p21 is differentially affected by ionizing and UV radiation. Mol Cell Biol 1997; 17: 355–363.
Lu X, Burbidge SA, Griffin S, Smith HM. Discordance between accumulated p53 protein level and its transcriptional activity in response to UV radiation. Oncogene 1996; 13: 413–418.
Dietrich C, Bartsch T, Schanz F, Oesch F, Wieser RJ. p53-dependent cell cycle arrest induced by N-acetyl-L-leucinyl-L-leuinyl-L-norleucinal in platelet-derived growth factor-stimulated human fiboblasts. Proc Natl Acad Sci USA 1996; 93: 10815–10819.
Midgley CM, Owens B, Briscoe CV, Thomas DB, Lane DP, Hall PA. Coupling between g irradiation, p53 induction, and the apoptotic response depends upon cell type in vivo. J Cell Sci 1995; 108: 1843–1848.
Linke SP, Clarkin KC, Leonardo AD, Tsou A, Wahl GM. A reversible, p53-dependent G0/G1 cell cycle arrest induced by ribonucleotide depeletion in the absence of detectable DNA damage. Genes & Develop 1996; 10: 934–947.
Ludwig RT, Bates S, Vousden KH. Differential activation of target cellular promoters by p53 mutants with impaired apoptotic function. Mol Cell Biol 1996; 16: 4952–4960.
Friedlander P, Haupt Y, Prives C, Oren M. A mutant p53 that discriminate between p53-responsive genes cannot induce apoptosis. Mol Cell Biol 1996; 16: 4961–4971.
Shieh S-Y, Ikeda M, Taya Y, Prives C. DNA damage-induced phosphorylation of p53 alleviates inhibition by mdm2. Cell 1997; 91: 325–334.
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Fallis, L.H., Richards, E., O'Connor, D.J. et al. The biological response of MCF7 breast cancer cells to proteosome inhibition or γ-radiation is unrelated to the level of p53 induction. Apoptosis 4, 99–107 (1999). https://doi.org/10.1023/A:1009614726059
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DOI: https://doi.org/10.1023/A:1009614726059