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Int J Biol Sci 2020; 16(7):1096-1106. doi:10.7150/ijbs.41246 This issue Cite

Research Paper

ATM Expression Is Elevated in Established Radiation-Resistant Breast Cancer Cells and Improves DNA Repair Efficiency

Lei Bian^1*, Yiling Meng^1*, Meichao Zhang^1*, Zhuying Guo², Furao Liu¹, Weiwen Zhang¹, Xue Ke¹, Yuxuan Su¹, Meng Wang¹, Yuan Yao^1✉, Lizhong Wu^3✉, Dong Li^1✉

1. Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
2. Department of Clinical Laboratory, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
3. Department of Radiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
*These authors contributed equally to this work.

✉ Corresponding authors: Dong Li, Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; E-mail: lidongedu.cn. Lizhong Wu, Department of Radiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, 280 Mohe Road, Shanghai, China, 201999. E-mail: woolleyedu.cn. Yuan Yao, Department of Radiation Oncology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; E-mail: yaoyuanedu.cn. More

Abstract

Repair of damaged DNA induced by radiation plays an important role in the development of radioresistance, which greatly restricts patients' benefit from radiotherapy. However, the relation between radioresistance development and DNA double-strand break repair pathways (mainly non-homologous end joining and homologous recombination) and how these pathways contribute to radioresistance are unclear. Here, we established a radioresistant breast cancer cell line by repeated ionizing radiation and studied the alteration in DNA repair capacity. Compared with parental sham-treated cells, radioresistant breast cancer cells present elevated radioresistance, enhanced malignancy, increased expression of Ataxia-telangiectasia mutated (ATM), and increased DNA damage repair efficiency, as reflected by accelerated γ-H2AX kinetic. These defects can be reversed by ATM inhibition or ATM knockdown, indicating a potential link between ATM, DNA repair pathway and radiosensitivity. We propose that cancer cells develop elevated radioresistance through enhanced DNA damage repair efficiency mediated by increased ATM expression. Our work might provide a new evidence supporting the potential of ATM as a potential target of cancer therapy.

Keywords: breast cancer, radiation, DNA damage repair, ATM

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