Abstract
Radiotherapy is one of the important treatments for patients with hepatocellular carcinoma. The treatment response (or efficacy), however, is limited in many patients due to acquired radiation resistance of cancer cells. Immediate-early response 5 (IER5) is one of the genes upregulated on radiation. The gene could modulate cell cycle checkpoint, leading to a decrease of cancer cell survival in response to radiation. To better understand how IRE5 expression is regulated on radiation, this study aims to identify transcription factors that interact with IER5 promoter region in liver cancer cell line. Using bioinformatic tool, we identified promoter region of IER5 gene. Subsequent luciferase reporter assay revealed two putative GC binding factor (GCF) binding sites. We found mutations of these binding sites increased the luciferase activity, suggesting a negative regulation of GCF on IER5 transcriptional activity. The physical interaction of GCF with the gene promoter was confirmed using chromatin immunoprecipitation and electrophoretic mobility shift assay assays. Different doses of radiation were also applied in these experiments, and we found the formation of protein-DNA complex reduced with the increasing dose of radiation. Together, we propose the GCF regulated transcriptional activity, at least in part, contributed to the upregulation of IER5 on radiation. The present findings provide insights into understanding the regulatory mechanisms of IER5.
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References
Parkin DM, Bray F, Ferlay J, Pisani P . Global cancer statistics, 2002. CA Cancer J Clin 2005; 55: 74–108.
Hertl M, Cosimi AB . Liver transplantation for malignancy. Oncologist 2005; 10: 269–281.
Long XH, Zhao ZQ, He XP, Wang HP, Xu QZ, An J et al. Dose-dependent expression changes of early response genes to ionizing radiation in human lymphoblastoid cells. Int J Mol Med 2007; 19: 607–615.
Kis E, Szatmari T, Keszei M, Farkas R, Esik O, Lumniczky K et al. Microarray analysis of radiation response genes in primary human fibroblasts. Int J Radiat Oncol Biol Phys 2006; 66: 1506–1514.
Ding K, Yang C, Shen J, Xu L, Li Y, Zhou P et al. Gamma-ray up-regulated holocarboxylase synthetase gene. Cell Mol Neurobiol 2009; 29: 383–389.
Ding KK, Shang ZF, Hao C, Xu QZ, Shen JJ, Yang CJ et al. Induced expression of the IER5 gene by gamma-ray irradiation and its involvement in cell cycle checkpoint control and survival. Radiat Environ Biophys 2009; 48: 205–213.
Williams M, Lyu MS, Yang YL, Lin EP, Dunbrack R, Birren B et al. Ier5, a novel member of the slow-kinetics immediate-early genes. Genomics 1999; 55: 327–334.
Cirelli C, Tononi G . Gene expression in the brain across the sleep-waking cycle. Brain Res 2000; 885: 303–321.
Okada A, Kushima K, Aoki Y, Bialer M, Fujiwara M . Identification of early-responsive genes correlated to valproic acid-induced neural tube defects in mice. Birth Defects Res A Clin Mol Teratol 2005; 73: 229–238.
Zeng F, Hon CC, Sit WH, Chow KY, Hui RK, Law IK et al. Molecular characterization of Coriolus versicolor PSP-induced apoptosis in human promyelotic leukemic HL-60 cells using cDNA microarray. Int J Oncol 2005; 27: 513–523.
Nakamura S, Nagata Y, Tan L, Takemura T, Shibata K, Fujie M et al. Transcriptional repression of Cdc25B by IER5 inhibits the proliferation of leukemic progenitor cells through NF-YB and p300 in acute myeloid leukemia. PLoS One 2011; 6: e28011.
Ishikawa Y, Sakurai H . Heat-induced expression of the immediate-early gene IER5 and its involvement in the proliferation of heat-shocked cells. FEBS J 2015; 282: 332–340.
Johnson AC, Kageyama R, Popescu NC, Pastan I . Expression and chromosomal localization of the gene for the human transcriptional repressor GCF. J Biol Chem 1992; 267: 1689–1694.
Kageyama R, Pastan I . Molecular cloning and characterization of a human DNA binding factor that represses transcription. Cell 1989; 59: 815–825.
Herbst RS . Review of epidermal growth factor receptor biology. Int J Radiat Oncol Biol Phys 2004; 59 (Suppl 2): 21–26.
Acknowledgements
This study was supported by The National Natural Science Foundation of China (Grant No’s. 30371232; and 30770533) and The National Basic Research Program of MOST, China (973 Program, Grant No. 2007CB914603).
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Yang, C., Yin, L., Zhou, P. et al. Transcriptional regulation of IER5 in response to radiation in HepG2. Cancer Gene Ther 23, 61–65 (2016). https://doi.org/10.1038/cgt.2016.1
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DOI: https://doi.org/10.1038/cgt.2016.1
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