Radiation-induced apoptosis, necrosis and G2 arrest in Fadu and Hep2 cells.
- Author:
Sam Sun LEE
1
;
Beom Hyun KANG
;
Hang Moon CHOI
;
In Seong JEON
;
Min Suk HEO
;
Soon Chul CHOI
Author Information
1. Department of Oral and Maxillofacial Radiology and Dental research Institute, College of Dentistry, Seoul National University, Korea. raychoi@snu.ac.kr
- Publication Type:Original Article
- Keywords:
Irradiation;
Apoptosis;
Necrosis;
Cell Cycle
- MeSH:
Apoptosis*;
Calcium;
Cell Count;
Cell Cycle;
Cell Cycle Checkpoints;
Cell Death;
Cell Line;
DNA;
Flow Cytometry;
Healthy Volunteers;
Humans;
Keratinocytes;
Lactic Acid;
Mouth Neoplasms;
Necrosis*;
Propidium;
Radiation Dosage;
Radiation Tolerance;
Radiation, Ionizing
- From:Korean Journal of Oral and Maxillofacial Radiology
2000;30(4):275-279
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: Radiation damage is produced and viable cell number is reduced. We need to know the type of cell death by the ionizing radiation and the amount and duration of cell cycle arrest. In this study, we want to identified the main cause of the cellular damage in the oral cancer cells and normal keratinocytes with clinical useful radiation dosage. MATERIALS AND METHODS: Human gingival tissue specimens obtained from healthy volunteers were used for primary culture of the normal human oral keratinocytes(NHOK). Primary NHOK were prepared from separated epithelial tissue and maintained in keratinocyte growth medium containing 0.15 mM calcium and a supplementary growth factor bullet kit as described previously. Fadu and Hep-2 cell lines were obtained from KCLB. Cells were irradiated in a (137)Cs gamma-irradiator at the dose of 10 Gy. The dose rate was 5.38 Gy/min. The necrotic cell death was examined with Lactate Dehydrogenase(LDH) activity in the culture medium. Every 4 day after irradiation, LDH activities were read and compared control group. Cell cycle phase distribution and preG1-incidence after radiation was analyzed by flow cytometry using Propidium Iodine(PI) staining. Cell cycle analysis were carried out with a FAC Star plus flowcytometry(FACS, Becton Dickinson, USA) and DNA histograms were processed with CELLFIT software(Becton Dickinson, USA). RESULTS: LDH activity increased in all of the experimental cells by the times. This pattern could be seen in the non-irradiated cells, and there was no difference between the non-irradiated cells and irradiated cells. We detected an induction of apoptosis after irradiation with a single dose of 10 Gy. The maximal rate of apoptosis ranged from 4.0% to 8.o% 4 days after irradiation. In all experimental cells, we detected G2/M arrest after irradiation with a single dose of 10 Gy. Yet there were differences in the number of G2/M arrested cells. The maximal rate of the G2/M ranges from 60.0% to 80.0% 24h after irradiation. There is no significant changes on the rate of the G0/G1 phase. CONCLUSION: Radiation sensitivity was not related with necrosis but cell cycle arrest and apoptosis. These data suggested that more arrested cell is correlated with more apoptosis.
