The Cellular Radiosensitivity Of Different Adenocarcinoma Cells Is Related To Their Egr-1 Expression Levels

Aims: To investigate the radiosensitivity of three adenocarcinoma cell lines with radioresistance ability and the role of Egr-1 in tumor radiosensitivity. Methods: Lung adenocarcinoma GLC-82 cell, colorectal cancer HT29 cell and cervical cancer Hela cell were used. Before and after radiation, colony formation ability was detected by colony formation assay, damages of DNA was determined by comet assay, and cell apoptosis induced by radiation and cell cycle distribution was detected by flow cytometry. Egr-1 expression level was analyzed by FQ-PCR and Western blot (WB). Results: Radiosensitivity of GLC-82 (SF2 = 0.532 +/- 0.003), HT29 (SF2 = 0.641 +/- 0.005) and Hela (SF2 = 0.641 +/- 0.005) cells decreased in sequence after irradiation. DNA damages and cell apoptosis of these cells were also decreased in sequence after irradiation. Cell cycle analysis showed G2/M phase arrest in these cells after irradiation. FQ-PCR showed that Egr-1 basic expression levels in GLC-82, HT29 and Hela cells were significantly different (F = 43.143, P = 0.000), from high to low in GLC-82 (1.094-fold), HT29 (0.793-fold), and Hela (0.529-fold) cells. The results of WB test were in accordance with that of FQ-PCR (F = 153.948, P = 0.000). Egr-1 expression induced by radiation in the three cell lines all peaked within 1 h. Irradiation-induced DNA damage, cell apoptosis and Egr-1 basic expressions were related to radiosensitivity parameters D-0 and SF2. Conclusion: Irradiation-induced DNA damage and cell apoptosis partly contributed to radiosensitivity of tumor, which may be positively related to basic expressions of Egr-1 gene in different cancer cells. Therefore, Egr-1 gene could hopefully be used for predicting radiosensitivity of tumor.