Effect of a poly(ADP-ribose) polymerase-1 inhibitor against esophageal squamous cell carcinoma cell lines.
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).
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
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Mentions: To assess whether the impairment of DSB repair is relevant to the sensitivity of TE-series cells to AZD2281, we evaluated X-ray irradiation-induced DNA DSBs in these cells. First, the amount of γ-H2AX was assessed by immunfluorescence. As mentioned above, the γ-H2AX level of TE-6 cells was high at baseline and increased 15 min after irradiation and sustained for 6 h. In TE-1 cells, increase of γ-H2AX level was observed 2 h after irradiation, but declined after 6 h (Fig. 5a,b). Next, a neutral comet assay was performed to assess DNA damage. This assay detects a wide range of DNA lesions, including DSBs; the tail moment parameter is used as an index of DNA damage. We found a sustained increase in the tail moment of TE-6 cells (irradiation [–]; 2.43 ± 3.19, 15 min; 5.27 ± 4.35 2 h; 9.78 ± 6.27, 6 h; 13.71 ± 8.20), while in TE-1 cells, the tail moment transiently increased at 2 h after 5 Gy X-ray irradiation and then returned to the basal level at 6 h (irradiation [–]; 3.69 ± 4.14, 15 min; 5.56 ± 3.97 2 h; 5.20 ± 4.22, 6 h; 3.20 ± 4.71) (Fig. 5c,d, Table 1). These results suggested that the X-ray irradiation-induced DNA damage was properly repaired in the TE-1 cells but was sustained in the TE-6 cells.
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.