Strain dependent differences in a quantitative histological study and expression analysis in irradiated murine lung

Although clinical observation can often reveal individual differences in the severity of lung fibrosis after radiation therapy, the actual influences of inherent individual factor is difficult to determine a clinical setting. In this paper, the usefulness of mouse model for research of heterogeneity in response of cancer treatment was investigated.C57BL/6J and C3H/HeMs mice were used for pathological and transcriotional experiments. The thorax of mice was locally irradiated at a dose of 10 or 20 Gy. Four-fold more CD44 positive cells had accumulated in the lungs of C3H/HeMs than of C57BL/6J mice. At sites of lung inflammation, HA accumulated at 12 hours after irradiation and the rapid resolution was achieved within 2 weeks in the lungs in both C57BL/6J mice and C3H/HheMs mice. An immunochemical investigation of C57BL/6J mice lungs revealed dense collagen accumulation at 8 weeks. The expression of Cap1, II18 and Rad51ap1 was constantly higher for 72 hours in C3H/HeMs mice than C57BL/6J mice. The expression of Mmp12 and Per3 was more induced in C3H/HeMs mice than C57BL/6J mice at 12 hours after irradiation. The expresion of Ltf was especially higher at 1 hour after iiradiation and that of Ifi202a was more induced at 72 hour in C57BL/6J mice than C3H/HeMs mice. Investigations into the mechanism of radiation-induced lung damage using animal models showed a powerful impact upon molecular studies of individual radiosensitivity.Mouse Models of Human Cancer (B7

Comet assay, a possible screening assay to classify subgroups of individuals with different radiosensitivity using high throughput scanning system for multiple samples of human blood lymphocytes.

This research was designed to identify the correlation between clinical radiosensitivity among breast cancer patients and in vitro radiosensitivity measured by alkaline comet assay in high throughput fashion. In 68 patients with breast cancer, acute adverse effects on skin after radiotherapy were clinically scored. Among these patients, maximum score was grade 0 for 10 patients, grade 1 for 28 patients, grade 2 for 25 patients, and grade 3 for 5 patients. Correlation between initial damage and skin reaction was found in breast cancer patients with grade 1 and grade 2, 3 (p= 0.034). There was also correlation between residual damage (RD) and skin reaction in these two groups (p= 0.033). Large inter-individual variation of RD was also noticed among breast cancer patients with grade 0 (17.5+- 12.7 %), or grade 2, 3 (16.8+- 10.7 %). By introducing a new analyzer with a motorinzed scanning stage for 8 slides, throughput of the comet assay data was highly improved. There was no difference in any comet parameter between cancer patients and age-matched 41 healthy volunteers. Our data suggests that the comet assay might be one of supportive assays to classify subpopulation of patients who have different radiosensitivity from normal responders with a fair discriminating capacity.International Comet Assay Workshop No.

Strain dependent differences in a quantitative histological study and expression analysis in irradiated murine lung

Although clinical observation can often reveal individual differences in the severity of lung fibrosis after radiation therapy, the actual influences of inherent individual factor is difficult to determine a clinical setting. In this paper, the usefulness of mouse model for research of heterogeneity in response of cancer treatment was investigated.C57BL/6J and C3H/HeMs mice were used for pathological and transcriotional experiments. The thorax of mice was locally irradiated at a dose of 10 or 20 Gy. Four-fold more CD44 positive cells had accumulated in the lungs of C3H/HeMs than of C57BL/6J mice. At sites of lung inflammation, HA accumulated at 12 hours after irradiation and the rapid resolution was achieved within 2 weeks in the lungs in both C57BL/6J mice and C3H/HheMs mice. An immunochemical investigation of C57BL/6J mice lungs revealed dense collagen accumulation at 8 weeks. The expression of Cap1, II18 and Rad51ap1 was constantly higher for 72 hours in C3H/HeMs mice than C57BL/6J mice. The expression of Mmp12 and Per3 was more induced in C3H/HeMs mice than C57BL/6J mice at 12 hours after irradiation. The expresion of Ltf was especially higher at 1 hour after iiradiation and that of Ifi202a was more induced at 72 hour in C57BL/6J mice than C3H/HeMs mice. Investigations into the mechanism of radiation-induced lung damage using animal models showed a powerful impact upon molecular studies of individual radiosensitivity.Mouse Models of Human Cancer (B7

Comet assay, a possible screening assay to classify subgroups of individuals with different radiosensitivity using high throughput scanning system for multiple samples of human blood lymphocytes

This research was designed to identify the correlation between clinical radiosensitivity among breast cancer patients and in vitro radiosensitivity measured by alkaline comet assay in high throughput fashion. In 62 patients with breast cancer and age-matched 41 healthy volunteers, acute adverse effects on skin after radiotherapy were clinically scored according to RTOG grading system. Maximum score during 6 months after radiotherapy was grade 0 for 9 patients, grade 1 for 25 patients, grade 2 for 24 patients, and grade 3 for 4 patients. The parameters of alkaline comet assay were initial damage, which was mean tail moment (MTM) values in irradiated cells in vitro immediately after irradiation with 5 Gy, and % residual damage (RD) at 15 min after irradiation. Correlation between initial damage and skin reaction was found in breast cancer patients with grade 1 and grade 2, 3 (p=0.017). There was no correlation between RD and skin reaction (p=0.056), while large inter-individual variation of RD was revealed among breast cancer patients with grade 0 (17.04 +13.31 %), or grade 2, 3 (16.86 +11.09 %). By introducing a new analyzer, throughput of the comet assay data was highly improved. Our data suggests that the comet assay might be one of supportive assays to classify subpopulation of patients who have different radiosensitivity from normal responders with a fair-poor discriminating capacity of the test to identify the patients with higher risk of developing a severe acute reaction.The 12th International Congress of Radiation Research(ICRR

Correlation between cellular radiosensitivity and DNA damage measured by the alkaline comet assay in human cancer cell lines.

In order to evaluate the usefulness of alkaline comet assay as a predictive assay of radiosensitivity, two parameters of comet assay and three parameters of cell survival curve were compared using 13 human cancer cell lines. Colony forming assay was performed after irradiation from 1 Gy to 6 Gy, and determined clonogenic survival parameters, such as D10, Dq and SF2. In comet assay, initial DNA damage (ID) immediatery after X-ray irradiation at dose of 8 Gy and residual damage (RD) at each 30 or 60 min after irradiation were assessed. Thirteen cell lines showed a broad spectrum in D10 value, ranging from 2.74 to 8.18, and Dq value, ranging from 0.29 to 3.42. ID varied from 1.87 to 9.09 among the cell lines, and RD varied from 0.66% to 56.51% at 30 min, and from 0% to 55.58% at 60 min. When cell lines were classified into two groups (group A and group B) according to each own D10 value, the group A, whose D10 value was more than 6, showed higher ID (5.4 + 2.3) than the group B (2.6 + 0.7), whose D10 values was less than 6 (P=0.008). There was, however, no correlation between ID and SF2. When cell lines were classified into two groups according to each own Dq value (group C and group D), the average of RD in group C, whose Dq value was more than 2, was 2.9% at 30 min. Group D whose Dq value is less than 2 was 15.6% at 30 min. The significant difference was observed between group C and group D (p= 0.049). These results suggest that the comet assay might be potential to classify a radiosensitive group according to ID and RD.International Comet Assay Workshop No.

Radiation induced chromosomal instability in lymphocytes of cancer patients

Cytokinesis-blocked micronucleus (CBMN) assay has been extensively used to evaluate the radiation sensitivity of human individuals. Using the CBMN assay, Scott et al (1998, 1999)demonstrated that a fraction of radiosensitive individuals in breast cancer case population was larger than in normal individual population. However, Vral et al were very skeptical about the Scott et al\u27 s findings (2002). Under the approval from the ethical committee of NIRS, peripheral blood was obtained from 46 normal healthy females, 131 breast cancer patients, 32 cervical cancer patients and 7 female head and neck cancer patients. Radiosensitivity of T-lymphocytes was assessed by using a CBMN assay. The frequencies of MN per binucleated cell in healthy donors were 0.031 (+/-0.010) and 0.151 (+/-0.066) for cells treated before and after X-ray-irradiation (2Gy), respectively. Spontaneous MN frequencies in cancer patients were significantly higher than healthy donors (p<0.001). Radiation sensitivities of breast- and head and neck-cancer patients were significantly higher than normal individuals (p<0.001). Cervical cancer patients were more resistant to irradiation than healthy donors, though the number of cases for statistical analysis was small (p<0.001). We are considering that the HPV infection affected the radiosensitivity of cervical cancer cases. Because it is widely believed that one key mechanism which leads to spontaneous micronucleus formation involves an imbalance of chromosomal segregation and a chromosomal instability in patients\u27 lymphocytes might be greater than that in normal individuals\u27 lymphocytes. Recently, Kuschel et al (2002) demonstrated that ratios in two SNPs on XRCC3 were significantly different between cancer patients and healthy females. Then, we can suppose that the radiation-related genes with low penetrance may be involved in tumorigenesis of mammary- and head & neck-cells, and also, in patients\u27 radiation susceptibility.The 12th International Congress of Radiation Research(ICRR

Inter-strain variation of apoptotic index of jejunal crypts between mouse systems after gamma ray whole body irradiation

In the clinic, interindividual differences in normal tissue response to radiotherapy have been observed and genetic factors are suggested to be responsible for this variation. Murine models have proven to be useful for the study of cytotoxic agents including radiation on the jejunum. We here report three murine strain differences in the levels of radiation-induced apoptosis in jejunal crypt cells. The apotosis positivity cell in jejunum carried out apoptosis index comparatively, and radiation susceptibility of strains was evaluated. Apoptosis index in C3 H/Hem was consistently lower than in A/J, or C57BL/6J at various times up to 24 hr after irradiation with 0.5 Gy. (P< 0.05). There was no difference among three strains after irradiation with 5 Gy. In the frequency of appearance of an apoptosis cell, C57BL/6J and A/J were radiation quantity susceptibility as compared with C3 H/Hem.日本放射線影響学会第４６回大