Downregulation of cytochrome c oxidase 1 induced radioresistance in esophageal squamous cell carcinoma

  • Authors:
    • Tomoko Takesue
    • Hirofumi Kawakubo
    • Tetsu Hayashida
    • Mai Tsutsui
    • Kazuhiro Miyao
    • Kazumasa Fukuda
    • Rieko Nakamura
    • Tsunehiro Takahashi
    • Norihito Wada
    • Hiroya Takeuchi
    • Yuko Kitagawa
  • View Affiliations

  • Published online on: August 1, 2017     https://doi.org/10.3892/ol.2017.6699
  • Pages: 4220-4224
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Abstract

Comprehensive gene screening with transposons is a novel procedure for the systematic identification of resistant genes. The present study aimed to use this technique to identify candidate radioresistant genes in esophageal squamous cell carcinoma. A transposon is a base sequence that can translocate to another location in the genome at random. By inserting the cytomegalovirus promotor as a transcriptional activator in the transposon, the following gene in the new location becomes overexpressed and the gene located at the transposon insertion site is downregulated. Consequently, various transposon-tagged cells, which have differentially overexpressed or downregulated genes using the transposon method can be obtained. Following the irradiation of transposon‑tagged cells, candidate radioresistant genes can be selected in order to detect the location of the transposon in the cells that have survived. A total of 11 genes were detected as candidate radioresistant genes. Cytochrome c oxidase 1 (MT‑CO1), an enzyme involved in apoptosis through the activation of the caspase cascade, was one of the candidate genes identified. The relative expression level of MT‑CO1 was 0.12 in MT‑CO1‑downregulated cells which was significantly lower compared with the expression level in parent TE4 cells (P<0.001). The survival rate was 28.7% in MT‑CO1‑downregulated cells and 10.5% in parent TE4 cells 9 days following 5‑Gy irradiation. The activity of cytochrome c and caspase‑3 following irradiation was significantly lower in the MT‑CO1‑downregulated radioresistant cells compared with in TE4 cells. In conclusion, the novel gene screening technique demonstrated to be useful for detecting candidate radioresistant genes in esophageal squamous cell carcinoma. The results of the present study revealed that the downregulation of MT‑CO1 induced radioresistance occurs by inhibiting the activation of the caspase cascade in radioresistant esophageal cancer cells.
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October-2017
Volume 14 Issue 4

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Spandidos Publications style
Takesue T, Kawakubo H, Hayashida T, Tsutsui M, Miyao K, Fukuda K, Nakamura R, Takahashi T, Wada N, Takeuchi H, Takeuchi H, et al: Downregulation of cytochrome c oxidase 1 induced radioresistance in esophageal squamous cell carcinoma. Oncol Lett 14: 4220-4224, 2017
APA
Takesue, T., Kawakubo, H., Hayashida, T., Tsutsui, M., Miyao, K., Fukuda, K. ... Kitagawa, Y. (2017). Downregulation of cytochrome c oxidase 1 induced radioresistance in esophageal squamous cell carcinoma. Oncology Letters, 14, 4220-4224. https://doi.org/10.3892/ol.2017.6699
MLA
Takesue, T., Kawakubo, H., Hayashida, T., Tsutsui, M., Miyao, K., Fukuda, K., Nakamura, R., Takahashi, T., Wada, N., Takeuchi, H., Kitagawa, Y."Downregulation of cytochrome c oxidase 1 induced radioresistance in esophageal squamous cell carcinoma". Oncology Letters 14.4 (2017): 4220-4224.
Chicago
Takesue, T., Kawakubo, H., Hayashida, T., Tsutsui, M., Miyao, K., Fukuda, K., Nakamura, R., Takahashi, T., Wada, N., Takeuchi, H., Kitagawa, Y."Downregulation of cytochrome c oxidase 1 induced radioresistance in esophageal squamous cell carcinoma". Oncology Letters 14, no. 4 (2017): 4220-4224. https://doi.org/10.3892/ol.2017.6699