• Radiation Oncology Journal
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• v.19 no.3
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• pp.252-258
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• 2001

Purpose : The objectives of this study are to investigate the significance of apoptotic death compared to total cell death after $\gamma-ray$ irradiation in human H&N cancer cell lines and to find out correlation between apoptosis and radiation sensitivity. Materials and method : Head and neck cancer cell lines (PCI-1, PCI-13, and SNU-1066), leukemia cell line (CCRF-CEM), and fibroblast cell line (LM217) as a normal control were used for this study. Cells were irradiated using Cs-137 animal experiment irradiator. Total cell death was measured by clonogenic assay. Annexin-V staining was used to detect the fraction of apoptotic death. Results : Surviving fraction at 2 Gy (SF2) were 0.741, 0.544, 0.313, 0.302, and 0.100 for PCI-1, PCI-13, SNU-1066, CCRF-CEM, and LM217 cell lines, respectively. Apoptosis was detected in all cell lines. Apoptotic index reached peak value at 72 hours after irradiation in head and neck cancer cell lines, and that was at 24 hours in CCRF-CEM and LM217. Total cell death increased exponentially with increasing radiation dose from 0 Gy to 8 Gy, but the change was minimal in apoptotic index. Apoptotic fractions at 2 Gy were $46\%,\;48\%,\;46\%,\;24\%,\;and\;19\%$ and at 6 Gy were $20\%,\;33\%,\;35\%,\;17\%,\;and\;20\%$ for PCI-1, PCI-13, SNU-1066, CCRF-CEM, and LM217, respectively. The radioresistant cell lines showed more higher apoptotic fraction at 2 Gy, but there was not such correlation at 6 Gy. Conclusion : All cell lines used in this study showed apoptosis after irradiation, but time course of apoptosis was different from that of leukemia cell line and normal fibroblast cell line. Reproductive cell death was more important mode of cell death than apoptotic death in all cell lines used in this study. But there was correlation between apoptotic fraction and radiation sensitivity at 2 Gy.

• Journal of Korean Society of Forest Science
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• v.25 no.1
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• pp.73-79
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• 1975

The Koran native economic and ornamental trees consisting 12 species of 4 gymnosperm families and 3 strains, 6 varieties and 18 species of 12 angiosperm families were irradiated by X-and ${\gamma}$-ray at three different dose rates; 1) acute, 2) semi-acute, and 3) chronic irradiation in order to know their radiosensitivities and the radition effects on mutation induction. Different materials such as seeds, cuttings, scions and plants of the above trees were used in this study, depended upon tree. Most of the materials irradiated showed a high radiosensitivity. The LD-50 of conifer trees ranged from 1.2kR to 13.2kR, averaging 5.4kR which was remarkably higher than field crops. On the other hand the LD-50 dose of hard wood trees ranged from 7.0kR to 18.5kR, averaging 12.7kR. All the tested trees were classified into several categories based upon the relative radiosensitivity of each species which was measured at the dose of LD-50. Variegation was most common among the induced mutants. The other mutations were albino, chlorophyll deficiency, deformed leaf and fruits. It was noticeable that giant-leaf bud-sport mutants were induced in Chinese chestnut (Castanea bungeana) and yellow leaf bud-sport ones appeared in oriental arborvitae (Thuja orientalis).

• Radiation Oncology Journal
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• v.26 no.3
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• pp.166-172
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• 2008

Purpose: The measurement of radiosensitivity of individuals is useful in radiation therapy. Unfortunately, the measurement of radiation survival using a clonogenic assay, which is the established standard, can be difficult and time consuming. The aim of this study is to compare radiosensitivity results obtained from the MTT and clonogenic assays, and to evaluate whether the MTT assay can be used on clinical specimens. Materials and Methods: HCT-8, LoVo, CT-26, and WiDr were the colon cancer cell lines used for this study. The clonogenic assay was performed to obtain the cell survival curves and surviving fractions at a dose of 2 Gy ($SF_2$) as the standard technique for radiosensitivity. Also, the MTT assay was performed for each of the cell lines (in vitro). To simulate clinical specimens, the cell lines were inoculated into nude mice, removed when the tumors reached 1 cm in diameter, and chopped. Next, the tumors were subjected to the same process involved with the MTT assay in vitro. The inhibition rates (IR) of 10 Gy or 20 Gy of irradiation for in vitro and ex vivo were calculated based on the optical density of the MTT assay, respectively. Results: According to $SF_2$ and the cell survival curve, the HCT-8 and WiDr cell lines were more resistant to radiation than LoVo and CT-26 (p<0.05). The IR was measured by in vitro. The MTT assay IR was 17.3%, 21%, 30% and 56.5% for the WiDr, HCT-8, LoVo and CT-26 cell lines, respectively. In addition, the IR measured ex vivo by the MTT assay was 23.5%, 26%, 38% and 53% in the HCT-8, WiDr, LoVo and CT-26 tumors, respectively. Conclusion: The radiosensitivity measured by the MTT assay was correlated with the measures obtained from the clonogenic assay. This result highlights the possibility that the MTT assay could be used in clinical specimens for individual radiosensitivity assays.

• Radioisotope journal
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• v.17 no.3
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• pp.54-62
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• 2002

• Radiation Oncology Journal
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• v.23 no.1
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• pp.51-60
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• 2005

Purpose : Selective inhibition of multiple molecular targets may improve the antitumor activity of radiation. Two specific inhibitors of selective cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) were combined with radiation on the HeLa cell line. To investigate cooperative mechanism with selective COX-2 inhibitor and EGFR blocker, in vitro experiments were done. Materials and Methods : Antitumor effect was obtained by growth inhibition and apoptosis analysis by annexin V-Flous method. Radiation modulation effects were determined by the clonogenic cell survival assay. Surviving fractions at 2 Gy ($SF_2$) and dose enhancement ratio at a surviving fraction of 0.25 were evaluated. To investigate the mechanism of the modulation of radiosensitivity, the cell cycle analyses were done by flow cytometry. The bcl-2 and bax expressions were analyzed by western blot. Results : A cooperative effect were observed on the apoptosis of the HeLa ceil line when combination of the two drugs, AG 1478 and NS 398 with radiation at the lowest doses, apoptosis of $22.70\%$ compare with combination of the one drug with radiation, apoptosis of $8.49\%$. In cell cycle analysis, accumulation of cell on $G_0/G_l$ phase and decrement of S phase fraction was observed from 24 hours to 72 hours after treatment with radiation, AG 1478 and NS 398. The combination of NS 398 and AG 1478 enhanced radiosensitivity on a concentration-dependent manner in HeLa cells with dose enhancement ratios of 3.00 and $SF_2$ of 0.12 but the combination of one drug with radiation was not enhanced radlosensitivity with dose enhancement ratios of 1.12 and SF2 of 0.68 (p=0.005). The expression levels of bcl-2 and bax were reduced when combined with AG 1478 and NS 398. Conclusion : Our results indicate that the selective COX-2 inhibitor and EGFR blocker combined with radiation have potential additive or cooperative effects on radiation treatment and may act through various mechanisms including direct inhibition of tumor cell proliferation, suppression of tumor cell cycle progression and inhibition of anti-apoptotic proteins.

• Radiation Oncology Journal
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• v.12 no.1
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• pp.9-16
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• 1994

Hypothesis that hypoxic tumors should be more responsive to the addition of preferential hypoxic cell cytotoxin SR 4233 (tirapazamine) to fractionated irradiation was tested in the mouse SCCVll carcinoma and RIF-1 sarcoma, Model of hypoxic tumor was established using the tumor bed effect: tumors growing in the preirradiated tissue (preirradiated tumors) were more hypoxic than tumors growing in the unirradiated tissue (unirradiated tumors). When the tumors reached a mean volume of 100 $mm^{3}$, both unirradiated and preirradiated tumors were treated with a fractionated course of 6${\times}$2 Gy in 3 days or 8${\times}$2.5 Gy in 4 days with SR 4233 (0.08 mmol/kg/injection) given 30 minutes before each irradiation or without SR 4233. Compared to the unirradiated tumors, hypoxic preirradiated tumors were approximately 5 times more resistant to fractionated irradiation alone but were approximately 5 times more responsive to SR 4233. Addition of SR 4233 Potentiated the effect of fractionated irradiation in both unirradiated and preirradiated tumors. Potentiation in the preirradiated tumors was morequal to or greater than that in the unirradiated tumors and seemed to be higher for more fractionated treatment. We confirm the hypothesis in a transplantable mouse tumor. Present results suggest that radioresistance of some hypoxic tumors can be overcome with hypoxic cytotoxin.

• Radiation Oncology Journal
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• v.25 no.4
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• pp.233-241
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• 2007

Purpose: We examined the effect of the dual EGFR/HER2 tyrosine kinase inhibitor, GW572016, on EGFR/HER2 receptor phosphorylation, inhibition of downstream signaling and radiosensitization in either an EGFR or HER2 overexpressing human breast cancer xenograft. Materials and Methods: We established SCID mice xenografts from 4 human breast cancer cell line that overexpressed EGFR or HER 2 (SUM 102, SUM 149, SUM 185, SUM 225). Two series of xenografts were established. One series was established for determining inhibition of the EGFR/HER2 receptor and downstream signaling activities by GW572016. The other series was established for determining the radiosensitization effect of GW572016. Inhibition of the receptor and downstream signaling proteins were measured by the use of immunoprecipitation and Western blotting. For determining the in vivo radiosensitization effect of GW572016, we compared tumor growth delay curves in the following four treatment arms: a) control; b) GW572016 alone; c) radiotherapy (RT) alone; d) GW572016 and RT. Results: GW572016 inhibited EGFR, HER2 receptor phosphorylation in SUM 149 and SUM 185 xenografts. In addition, the p44/42 MAPK (ERK 1/2) downstream signaling pathway was inactivated by GW572016 in the SUM 185 xenograft. In the SUM 225 xenograft, we could not observe inhibition of HER2 receptor phosphorylation by GW572016; both p44/42 MAPK (Erk1/2) and Akt downstream signal protein phosphorylation were inhibited by GW572016. GW572016 inhibited growth of the tumor xenograft of SUM 149 and SUM 185. The combination of GW572016 and RT enhanced growth inhibition greater than that with GW572016 alone or with RT alone in the SUM 149 xenograft. GW572016 appears to act as an in vivo radiosensitizer. Conclusion: GW572016 inhibited EGFR/HER2 receptor phosphorylation and downstream signaling pathway proteins. GW572016 modestly inhibited the growth of tumor in the SUM 185 xenograft and showed radiosensitization in the SUM 149 xenograft. Our results suggest that a better predictor of radiation response would be inhibition of a crucial signaling pathway than inhibition of a receptor.

• Journal of the Korean Society of Radiology
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• v.10 no.6
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• pp.387-393
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• 2016

Tumor using the efficient concomitant radiotherapy and chemotherapy to remove, prior to surgery and, either reduce the size of the tumor after surgery, or was can be made smaller, Or excised tumor, in a way to be removed, most conventional surgical method is surgical excision surgery therapy. And methods reduce or tumor size, or smaller, chemotherapy can kill tumor is administered selectively anticancer agent which increases the radioactive susceptible to tumor cells, sensitive to susceptibility to radiation are those which make it possible to respond to, either TRAIL methods of various biological cytostatic can deform the protein, by deforming the structure of the protein help to cell death it is known. In this paper, the HCT-116 cells thought to be a cancer cell to analyze the interaction of TRAIL and radiation. Experimental results, single use of TRAIL and radiation, results were compared with the control group, it was found to have no significant effect on each cell proliferation and apoptosis. Conversely treated with TRAIL, when treated in parallel radiation, it was possible to know that the HCT-116 cells significantly apoptosis occurs, The proportion of G1 ratio G0 also was found to have increased. TRAIL conclusion is increased apoptosis radiation defensive cells can know that increased radiosensitivity, also possible to alter the cell cycle, reduce cell proliferation ability stepwise it was possible. TRAIL is increased apoptosis, decreased cell proliferative capacity, it is considered to be possible to use as a radiation sensitizer.

• Radiation Oncology Journal
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• v.18 no.4
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• pp.329-336
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• 2000

Backgrounds : The purpose of this study was to identify drugs that can enhance radioresponse of murine fepatocarcinorna. Methods : CSH/HeJ mice bearing 8 mm tumors of murine fepatocarcinorna, HCa-1, were treated with 25 Gy radiation and one of the following drugs: 5-Fu, 150 mghg; adriamycin, 8 mg/kg; cisplatin, 6 mg/kg; paclitaxel, 40 mg/kg; and gemcitabine, 50 mg/kg. Tumor response to the treatment was determined by tumor growth delay assay and by enhancement factor. Apoptotic level was assessed in tissue sections. Expression of regulating molecules was analyzed by western blotting for p53, Bcl-2, Bax, Bcl-XL, Bcl-XS, and p21$^{WAF1/CIP1}$. Results :Among the drugs tested, only gemcitabine enhanced the antitumor effect of radiation, with enhancement factor of 1.6. Induction of apoptosis by a combination of gemcitabine and radiation was shown as only additive level. In analysis of radiation-induced expression of regulating molecules, the most significant change by combining gemcitabine was activation of p21$^{WAF1/CIP1}$ Conclusion :Gemcitabine is the first drug showing an enhancement of radioresponse in murine hepatocarcinoma, when combined with radiation. The key element of enhancement is thought to be p21$^{WAF1/CIP1}$.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2001.09a
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• pp.23-23
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• 2001

대표적인 어류질병의 원인이 되는 주요 병원성 미생물인 에드워드균(Edwardsiella tarda), 비브리오균(Vibrio anguillarum), 연쇄구균(Streptococcus faecalis)의 방사선 감수성을 파악하고, 주요 생어사료재료 3종(고등어, 전어, 새우) 및 배합사료 1종을 대상으로 일반세균의 방사선 멸균 효과 및 생어사료에 병원성 세균을 인위적으로 오염시킨 후 방사선 조사에 의한 멸균 효과를 파악하였다. (중략)