Delayed expression of hpS2 and prolonged expression of CIP1/WAF1/SDI1 in human tumour cells irradiated with X-rays, fission neutrons or 1 GeV/nucleon Fe ions

• Published in: International journal of radiation biology Vol. 75; no. 5; pp. 529 - 541
• Main Authors: Balcer-Kubiczek, E. K., Zhang, X. F., Harrison, G. H., Zhou, X. J., Vigneulle, R. M., Ove, R., McCready, W. A., Xu, J. F.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Informa UK Ltd 01.05.1999; Taylor & Francis
• Subjects: Biological and medical sciences; Cell Survival - radiation effects; Cyclin-Dependent Kinase Inhibitor p21; Cyclins - genetics; DNA, Complementary - isolation & purification; Female; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression - drug effects; Genes, p53; Humans; Life Sciences (General); Molecular and cellular biology; Molecular genetics; Neutrons; Nuclear Proteins; Proteins - genetics; Proto-Oncogene Proteins - genetics; Proto-Oncogene Proteins c-mdm2; Receptors, Estrogen - genetics; Relative Biological Effectiveness; RNA, Messenger - analysis; Trefoil Factor-1; Tumor Cells, Cultured; Tumor Suppressor Proteins; X-Rays; Nasa Discipline Radiation Health; Non-Nasa Center; Transcription; Relative biological effectiveness; Gene expression; X ray irradiation; Northern blotting; Clonogenic assay; Phenotype; Ionizing radiation; Iron ion; Fission product; DNA; Neutron irradiation; Molecular biology; Tumor cell; NASA Discipline Radiation Health; Non-NASA Center
• ISSN: 0955-3002; 1362-3095
• DOI: 10.1080/095530099140177

Purpose : Differences in gene expression underlie the phenotypic differences between irradiated and unirradiated cells. The goal was to identify late-transcribed genes following irradiations differing in quality, and to determine the RBE of 1 GeV/n Fe ions. Materials and methods : Clonogenic assay was used to determine the RBE of Fe ions. Differential hybridization to cDNA target clones was used to detect differences in expression of corresponding genes in mRNA samples isolated from MCF7 cells irradiated with iso-survival doses of Fe ions (0 or 2.5Gy) or fission neutrons (0 or 1.2Gy) 7 days earlier. Northern analysis was used to confirm differential expression of cDNA-specific mRNA and to examine expression kinetics up to 2 weeks after irradiation. Results : Fe ion RBE values were between 2.2 and 2.6 in the lines examined. Two of 17 differentially expressed cDNA clones were characterized. hpS2 mRNA was elevated from 1 to 14 days after irradiation, whereas CIP1/WAF1/SDI1 remained elevated from 3h to 14 days after irradiation. Induction of hpS2 mRNA by irradiation was independent of p53, whereas induction of CIP1/WAF1/SDI1 was observed only in wild-type p53 lines. Conclusions : A set of coordinately regulated genes, some of which are independent of p53, is associated with change in gene expression during the first 2 weeks post-irradiation.