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Effect of a poly(ADP-ribose) polymerase-1 inhibitor against esophageal squamous cell carcinoma cell lines.

Nasuno T, Mimaki S, Okamoto M, Esumi H, Tsuchihara K - Cancer Sci. (2013)

Bottom Line: Effective molecular target drugs that improve therapeutic efficacy with fewer adverse effects for esophageal cancer are highly anticipated.Of these eight cell lines, the clonogenic survival of one (TE-6) was reduced by AZD2281 to the level of DSB repair-defective Capan-1 and HCC1937 cells.Interestingly, a strong correlation between basal expression levels of γ-H2AX and sensitivity to AZD2281was observed in the TE-series cells (R(2)  = 0.5345).

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Affiliation: Division of Translational Research, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa, Chiba, Japan; Department of Otorhinolaryngology, University of Kitasato Hospital, Minami-ku, Sagamihara, Kanagawa, Japan.

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Impairment of 53BP1 and RAD51 nuclear focus formation in X-ray irradiated TE-6 cells. (a) TE-6 and TE-1 cells were irradiated with 2 Gy of X-rays and fixed 15 min and 2 h after irradiation. The formation of 53BP1 nuclear foci was evaluated by immunofluorescence. (b) Scatter diagrams showing the number of 53BP1 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. *P < 0.05, **P < 0.01 (Student's t-test). (c) TE-6 and TE-1 cells were irradiated with 10 Gy of X-rays and fixed 6 h after irradiation. The formation of RAD51 nuclear foci was evaluated by immunofluorescence. (d) Scatter diagrams showing the number of RAD51 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. **P < 0.01 (Student's t-test).
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fig06: Impairment of 53BP1 and RAD51 nuclear focus formation in X-ray irradiated TE-6 cells. (a) TE-6 and TE-1 cells were irradiated with 2 Gy of X-rays and fixed 15 min and 2 h after irradiation. The formation of 53BP1 nuclear foci was evaluated by immunofluorescence. (b) Scatter diagrams showing the number of 53BP1 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. *P < 0.05, **P < 0.01 (Student's t-test). (c) TE-6 and TE-1 cells were irradiated with 10 Gy of X-rays and fixed 6 h after irradiation. The formation of RAD51 nuclear foci was evaluated by immunofluorescence. (d) Scatter diagrams showing the number of RAD51 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. **P < 0.01 (Student's t-test).

Mentions: Because the TE-6 cells were found to be defective in DSB repair, we assessed the amount of BRCA1/2 expression in TE-series cells by Western blotting (Fig. S4a,b). However, no significant difference in the expression of BRCA1/2 in TE-6 and TE-1 cells was observed. To confirm the impairment of DNA repair machinery of TE-6 cells, we evaluated the nuclear focus formation of 53BP1, which is recruited to the γ-H2AX sites at an early stage in DSB repair, and RAD51, which is recruited at a late stage in DSB repair.(24–26) The baseline expression levels of 53BP1 and RAD51 were higher in the TE-6 cells (Fig. S5). However, increase of the number of 53BP1 nuclear foci per cell was much less in the TE-6 cells (irradiation [–]; 0.55 ± 1.44, 15 min; 0.94 ± 1.12 2 h; 1.48 ± 1.20), whereas 53BP1 foci were increased in the TE-1 cells (irradiation [–]; 1.09 ± 1.58, 15 min; 2.48 ± 2.44 2 h; 4.86 ± 3.23) (Fig. 6a,b, Table 2). Similarly, 6 h after 10 Gy X-ray irradiation, the number of RAD51 foci per cell was significantly increased in the TE-1 cells (irradiation [–]; 1.11 ± 1.50, 6 h; 3.65 ± 3.59), whereas the increase in RAD51 foci was not significant in the TE-6 cells (irradiation [–]; 0.67 ± 2.20, 2 h; 2.25 ± 3.20) (Fig. 6c,d, Table 2). These results suggested that the interaction between γ-H2AX and 53BP1 and the subsequent recruitment of RAD51 were impaired in TE-6 cells.


Effect of a poly(ADP-ribose) polymerase-1 inhibitor against esophageal squamous cell carcinoma cell lines.

Nasuno T, Mimaki S, Okamoto M, Esumi H, Tsuchihara K - Cancer Sci. (2013)

Impairment of 53BP1 and RAD51 nuclear focus formation in X-ray irradiated TE-6 cells. (a) TE-6 and TE-1 cells were irradiated with 2 Gy of X-rays and fixed 15 min and 2 h after irradiation. The formation of 53BP1 nuclear foci was evaluated by immunofluorescence. (b) Scatter diagrams showing the number of 53BP1 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. *P < 0.05, **P < 0.01 (Student's t-test). (c) TE-6 and TE-1 cells were irradiated with 10 Gy of X-rays and fixed 6 h after irradiation. The formation of RAD51 nuclear foci was evaluated by immunofluorescence. (d) Scatter diagrams showing the number of RAD51 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. **P < 0.01 (Student's t-test).
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fig06: Impairment of 53BP1 and RAD51 nuclear focus formation in X-ray irradiated TE-6 cells. (a) TE-6 and TE-1 cells were irradiated with 2 Gy of X-rays and fixed 15 min and 2 h after irradiation. The formation of 53BP1 nuclear foci was evaluated by immunofluorescence. (b) Scatter diagrams showing the number of 53BP1 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. *P < 0.05, **P < 0.01 (Student's t-test). (c) TE-6 and TE-1 cells were irradiated with 10 Gy of X-rays and fixed 6 h after irradiation. The formation of RAD51 nuclear foci was evaluated by immunofluorescence. (d) Scatter diagrams showing the number of RAD51 foci in individual cells. The lines shown indicate the mean of the data plotted. The data were obtained from at least 100 cells for each condition. **P < 0.01 (Student's t-test).
Mentions: Because the TE-6 cells were found to be defective in DSB repair, we assessed the amount of BRCA1/2 expression in TE-series cells by Western blotting (Fig. S4a,b). However, no significant difference in the expression of BRCA1/2 in TE-6 and TE-1 cells was observed. To confirm the impairment of DNA repair machinery of TE-6 cells, we evaluated the nuclear focus formation of 53BP1, which is recruited to the γ-H2AX sites at an early stage in DSB repair, and RAD51, which is recruited at a late stage in DSB repair.(24–26) The baseline expression levels of 53BP1 and RAD51 were higher in the TE-6 cells (Fig. S5). However, increase of the number of 53BP1 nuclear foci per cell was much less in the TE-6 cells (irradiation [–]; 0.55 ± 1.44, 15 min; 0.94 ± 1.12 2 h; 1.48 ± 1.20), whereas 53BP1 foci were increased in the TE-1 cells (irradiation [–]; 1.09 ± 1.58, 15 min; 2.48 ± 2.44 2 h; 4.86 ± 3.23) (Fig. 6a,b, Table 2). Similarly, 6 h after 10 Gy X-ray irradiation, the number of RAD51 foci per cell was significantly increased in the TE-1 cells (irradiation [–]; 1.11 ± 1.50, 6 h; 3.65 ± 3.59), whereas the increase in RAD51 foci was not significant in the TE-6 cells (irradiation [–]; 0.67 ± 2.20, 2 h; 2.25 ± 3.20) (Fig. 6c,d, Table 2). These results suggested that the interaction between γ-H2AX and 53BP1 and the subsequent recruitment of RAD51 were impaired in TE-6 cells.

Bottom Line: Effective molecular target drugs that improve therapeutic efficacy with fewer adverse effects for esophageal cancer are highly anticipated.Of these eight cell lines, the clonogenic survival of one (TE-6) was reduced by AZD2281 to the level of DSB repair-defective Capan-1 and HCC1937 cells.Interestingly, a strong correlation between basal expression levels of γ-H2AX and sensitivity to AZD2281was observed in the TE-series cells (R(2)  = 0.5345).

View Article: PubMed Central - PubMed

Affiliation: Division of Translational Research, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa, Chiba, Japan; Department of Otorhinolaryngology, University of Kitasato Hospital, Minami-ku, Sagamihara, Kanagawa, Japan.

Show MeSH
Related in: MedlinePlus