Abstract
Abstract. Reports on the p53‐related cell cycle and apoptotic responses of EBV‐transformed lymphoblastoid cell lines to DNA damage have led to some confusion. This may be due to differences in the nature of the specific p53 mutations under examination, but it can also be partly attributed to methodological and analytical problems (e.g. the inappropriate use of static DNA histograms for cell cycle analysis). Taking seven lymphoblastoid cell lines derived from both normal individuals and Li‐Fraumeni Syndrome/Li‐Fraumeni‐Like (LFS/LFL) patients of differing p53 status, we completed a detailed study of radiation‐induced cell cycle perturbations. Using BrdUrd pulse labelling and flow cytometry it was found that, regardless of p53 status, the cells did not arrest in G1 despite all of the lines showing p53 upregulation 3 hours postirradiation. The irradiated cells did, however, show a general slowing both in S‐phase entry from G1 and in movement through S‐phase. These facts would not have been apparent from the analysis of static DNA histograms. The problems with the use of static methods to assess changes in the dynamics of cell cycle progression apply not only to studies involving EBV‐transformed cell lines, but also to a wide range of investigations into the molecular control of cell proliferation.
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REFERENCES
- Begg AC, Mcnally NJ, Shreive DC, Karcher H. (1985) A method to measure the duration of DNA synthesis and the potential doubling time from a single sample. Cytometry 6, 620. [DOI] [PubMed] [Google Scholar]
- Birch JM, Hartley AL, Tricker KJ et al. (1994) Prevalence and diversity of constitutional mutations in the p53 gene among 21 Li‐Fraumeni families. Cancer Res. 54, 1298. [PubMed] [Google Scholar]
- Camplejohn RS, Perry P, Hodgson SV et al. (1995) A possible screening test for inherited p53‐related defects based on the apoptotic response of peripheral blood lymphocytes to DNA damage. Br. J. Cancer 72, 654. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clarke OAR, Purdie CA, Harrison DJ et al. (1993) Thymocyte apoptosis induced by p53‐dependent and independent pathways. Nature 362, 849. [DOI] [PubMed] [Google Scholar]
- Delia D, Goi K, Mizutani S et al (1997) Dissociation between cell cycle arrest and apoptosis can occur in Li‐Fraumeni cells heterozygous for p53 gene mutations. Oncogene 14, 2137. [DOI] [PubMed] [Google Scholar]
- Gilchrist R, Lomax ME, Camplejohn RS. (1998) Cell cycle perturbations and apoptosis in EBV‐transformed lymphoblastoid cell lines of differing p53 status following gamma radiation. Br. J. Cancer 78 (Suppl. 1), 38. [Google Scholar]
- Goi K, Takagi M, Iwata S et al. (1997) DNA damage‐associated dysregulation of the cell cycle and apoptosis control in cells with germline p53 mutation. Cancer Res. 57, 1895. [PubMed] [Google Scholar]
- Lalle P, Moyret‐Lalle C, Wang Q et al. (1995) Genomic stability and wild‐type p53 function of lymphoblastoid cells with germline p53 mutation. Oncogene 10, 2447. [PubMed] [Google Scholar]
- Li FP, Fraumeni JF. (1969) Soft‐tissue sarcomas, breast cancer and other neoplasms. Annals Int. Med. 71, 747. [DOI] [PubMed] [Google Scholar]
- Little JB, Nagasawa H, Keng PC, Yu Y, Li CY. (1995) Absence of radiation‐induced G1 arrest in two closely related human lymphoblast cell lines that differ in p53 status. J. Biol. Chem 270, 11033. [DOI] [PubMed] [Google Scholar]
- Lomax ME, Barnes DM, Gilchrist R, Picksley SM, Varley JM, Camplejohn RS. (1997) Two functional assays employed to detect an unusual mutation in the oligomerisation domain of p53 in a Li‐Fraumeni like family. Oncogene 14, 1869. [DOI] [PubMed] [Google Scholar]
- Lomax ME, Barnes DM, Hupp TR, Picksley SM, Camplejohn RS. (1998) Characterisation of p53 oligomerization domain mutations isolated from Li‐Fraumeni and Li‐Fraumeni like family members. Oncogene 17, 643. [DOI] [PubMed] [Google Scholar]
- Malkin D, Li FP, Strong LC et al. (1990) Germline p53 mutations in a familial syndrome of breast cancer, sarcomas and other neoplasms. Science 250, 1233. [DOI] [PubMed] [Google Scholar]
- Okan I, Wang Y, Chen F et al. (1995) The EBV encoded LMP1 protein inhibits p53‐triggered apoptosis but not growth arrest. Oncogene 11, 1027. [PubMed] [Google Scholar]
- Quinn CM, Wright NA. (1990) The clinical assessment of proliferation and growth in human tumours: evaluation of methods and applications as prognostic variables. J. Pathol 160, 93. [DOI] [PubMed] [Google Scholar]
- Varley JM, Mcgowan G, Thorncroft M et al. (1997) Germ‐line mutations of TP53 in Li‐Fraumeni families: an extended study of 39 families. Cancer Res. 57, 3245. [PubMed] [Google Scholar]
- Williams KJ, Heighway J, Birch JM, Norton JD, Scott D. (1996) No defect in G1/S cell cycle arrest in irradiated Li‐Fraumeni lymphoblastoid cell lines. Br. J. Cancer 74, 698. [DOI] [PMC free article] [PubMed] [Google Scholar]
