• BMB Reports
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• v.34 no.2
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• pp.123-129
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• 2001

Cellular response to ionizing radiation is affected by cell types, radiation doses, and post-irradiation time. Based on the trypan blue dye exclusion assay in normal oral mucosal cells (OM cells), a 48 h post-irradiation was sufffcient and an adequate time point for the evaluation of radiation sensitivity Its $LD_{50}$ was approximately 1.83 Gy To investigate possible biomarkers useful for the biological radiodosimetry of normal epithelial cells (p53, c-fos, cyclin D1, cdc-2, pRb) EGF receptor phosphorylation and Erk activation were evaluated at different radiation doses and different post-irradiation times. From 0.5 Gy, p53 was accumulated in the nucleus of basal cells of the OM raft culture at 4 h post-irradiation and sustained up to 24 h post-irradiation, which suggests that radiation-induced apoptosis or damage repair was not yet completed. The number of p53 positive cells and biosynthesis of p53 were correlated with radiation doses. Both cyclin D1 and c-fos were only transiently induced within 1 h post-irradiation. Cyclin D1 was induced at all radiation doses. However, cfos induction was highest at 0.1 Gy, approximately 7.3 fold more induction than the control, whose induction was reduced in a reverse correlation with radiation dose. The phosphorylation pattern of cdc-2 and pRb were unaffected by radiation. In contrast to A431 tails overexpressing the EGF receptor approximately 8.5 fold higher than normal epithelial, the OM cells reduced the basal level of the EGF receptor phosphorylation in a radiation dose dependent fashion. In conclusion, among radiation-induced biomolecules, the p53 nuclear accumulation may be considered for the future development of a useful marker far biological radiodosimetry in normal epithelial tissue since it was sustained for a longer period and showed a dose response relationship. Specific c-fos induction at a low dose may also be an important finding in this study It needs to be studied further for the elucidation of its possible connection with the low dose radio-adaptive response.

• The Korean Journal of Nuclear Medicine
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• v.33 no.1
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• pp.94-99
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• 1999

Purpose: Radiation-induced chromosomal damage and apoptosis were compared in human lymphocytes. Materials and Methods: Peripheral lymphocytes from 10 normal volunteers (6 males, 4 females, age range $23{\sim}41$ years) were irradiated by gamma rays from a cell irradiator. Doses of irradiation were 0 (control), 0.18, 2, 5, 10, 20 and 25 Gy. Irradiated lymphocytes were examined by metaphase analysis for chromosomal aberrations and by flow cytometry for apoptosis. Results of both studies were compared according to dose. Results: Number of dicentric and ring chromosomes (D+R) was $0.5{\pm}0.53$ at baseline, which was significantly increased after radiation according to the dose. The fraction of cells showing annexin V-fluorescein isothiocyanate uptake was $0.51{\pm}$0.39%, which increased to $3.58{\pm}1.85%$ by 2 Gy irradiation, and then decreased. The fraction of cells showing propidium iodide (PI) uptake was $0.52{\pm}0.12%$, which significantly increased according to dose (upto $15.64{\pm}5.99%$ by 20 Gy irradiation). D+R and PI uptake were well correlated (r=0.84, p<0.001). Conclusion: Radiation-induced chromosomal aberration was correlated to nuclear uptake of PI, a marker of late apoptosis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.3
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• pp.506-512
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• 2000

건조 농산물을 비롯한 식품에 대한 방사선 조사가 허가, 시행되고 있으며, 그 적용 범위도 확대되고 있다. 이에 따라 건조 생약재의 위생화의 대체방법으로 방사선 조사 기술의 적용이 산업계로부터 요구되고 있다. 본 연구는 감마선 조사 생약재의 효능 변화 유무를 확인하기 위한 일환으로 수행되었다. 저자 등은 사물탕, 보중익기탕 및 삼령백출산 등이 방사선 방호 효과를 보이는 것으로 이미 보고한 바 있다. 본 실험에서는 감마선 조사(10 kGy)한 이들 한약제 각각의 방사선 방호 효과를 비조사 시료와 비교 평가하였다. 효과평가를 위하여 방사선 조사 마우스에서 소장움 생존시험, 내재성 비장집락 형성시험 및 apoptosis 측정을 시행하였다. 각 한약제의 감마선 조사 시료는 3가지 시험 모두에서 비조사 시료와 유사한 효과를 나타내었으며(p<0.05), 생체내 독성도 나타내지 않았다. 이는 생약재의 여러 가지 고유 효능 중 일부의 안정성으르 확인한 것으로 생각되며, 이 결과로 미루어 보아 감마선 조사 생약재의 효능 안정성은 한의학적 고유의 효능 비교 평가를 통하여 확인될 수 있을 것으로 사료된다. 한편, 저자 등은 감마선 조사 생약재의 유효성분 안정성 및 유전 독성학적 안전성을 확인하여 보고한 바 있다. 이들 결과를 토대로 향후 감마선 조사 행약재의 고유 효능의 안정성에 관한 체계적인 연구결과를 얻는다면 생약재의 위생화 수단으로 감마선 조사기술의 이용이 실용화될 수 있을 것으로 사료된다.

• Journal of Radiation Protection and Research
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• v.24 no.1
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• pp.17-22
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• 1999

This study was carried out to evaluate the biochemical and morphological effects of ionizing radiation on mouse ovarian follicles. Immature mice (ICR, 3 week-old) were irradiated with a dose of $LD_{80(30)}$ at KAERI. The ovaries were collected after 6 hours, 12 hours, 1 day, and 2 days post irradiation. With the morphological basis of the histological staining with hematoxylin-eosin, immunohistochemical preparation using in situ 3'-end labeling was evaluated. Flowcytometric evaluation of DNA extracted from the whole ovary was performed. The percentage of $A_0$ (subpopulation of cells with degraded DNA and with lower DNA fluorescence than $G_0/G_1$ cells), apoptotic, cells in the cell cycle was significantly higher in the irradiated group than in the control group. The number of in situ 3'-end labeled follicles increased at 6 hours post irradiation. All the analyses represented that the ionizing radiation-induced follicular atresia was taken place via an apoptotic degeneration. Such a degeneration underwent very fast and acutely. Therefore, it is concluded that the radiation-induced follicular degeneration is, like the spontaneous atresia, mediated by an acute apoptosis of follicular granulosa cells. Flowcytometric evaluation of cell cycles can make the role for quantifying the atretic follicles and understanding the mechanism of the radiation-induced cell death.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3301-3306
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• 2015

Nucleolin (C23) is an important anti-apoptotic protein that is ubiquitously expressed in exponentially growing eukaryotic cells. In order to understand the impact of C23 in radiation therapy, we attempted to investigate the relationship of C23 expression with the radiosensitivity of human non-small cell lung cancer (NSCLC) cells. We investigated the role of C23 in activating the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), which is a critical protein for DNA double-strand breaks (DSBs) repair. As a result, we found that the expression of C23 was negatively correlated with the radiosensitivity of NSCLC cell lines. In vitro clonogenic survival assays revealed that C23 knockdown increased the radiosensitivity of a human lung adenocarcinoma cell line, potentially through the promotion of radiation-induced apoptosis and adjusting the cell cycle to a more radiosensitive stage. Immunofluorescence data revealed an increasing quantity of ${gamma}$-H2AX foci and decreasing radiation-induced DNA damage repair following knockdown of C23. To further clarify the mechanism of C23 in DNA DSBs repair, we detected the expression of DNA-PKcs and C23 proteins in NSCLC cell lines. C23 might participate in DNA DSBs repair for the reason that the expression of DNA-PKcs decreased at 30, 60, 120 and 360 minutes after irradiation in C23 knockdown cells. Especially, the activity of DNA-PKcs phosphorylation sites at the S2056 and T2609 was significantly suppressed. Therefore we concluded that C23 knockdown can inhibit DNA-PKcs phosphorylation activity at the S2056 and T2609 sites, thus reducing the radiation damage repair and increasing the radiosensitivity of NSCLC cells. Taken together, the inhibition of C23 expression was shown to increase the radiosensitivity of NSCLC cells, as implied by the relevance to the notably decreased DNA-PKcs phosphorylation activity at the S2056 and T2609 clusters. Further research on targeted C23 treatment may promote effectiveness of radiotherapy and provide new targets for NSCLC patients.