Department of General Surgery, Huaihe Hospital of Henan University, Kaifeng, Henan Province 475001, China.
Center for Translational Medicine, Huaihe Hospital of Henan University, Kaifeng, Henan Province 475001, China.
Biosci Rep. 2019 Mar 19;39(3). doi: 10.1042/BSR20180893. Print 2019 Mar 29.
Radiotherapy is an important locoregional treatment, and its effect on triple-negative breast cancer (TNBC) needs to be enhanced. The aim of the present study was to investigate the potential effects of XRCC4 on radiosensitivity of TNBC.
The RNAi technique was implemented to establish the TNBC stable cell line with XRCC4 knockdown. MTT assay was used to detect the effect of XRCC4 knockdown on cell proliferation. Western blot and immunohistochemistry assays were employed to identify protein expression. Colony assay was performed to detect the effect of XRCC4 knockdown on the colony formation ability of TNBC cells with radiation treatment. Comet assay was conducted to evaluate the influence of XRCC4 silencing on DNA repair activity in ionizing radiation. In addition, we performed a survival analysis based on data in TCGA database.
XRCC4 knockdown by lentivirus-mediated shRNA had no significant effect on proliferation of TNBC cells. Knockdown of XRCC4 could substantially increase the sensitivity of TNBC cells to ionizing radiation. The DNA damage level was detected to be increased in the XRCC4 knockdown group, indicating there was a significant repair delay in the XRCC4-deleted cells. Clinical sample analysis exhibited that there were various XRCC4 expression in different patients with TNBC. Moreover, survival analysis showed that high expression of XRCC4 was significantly associated with poor progression-free survival after radiotherapy in TNBC patients. Conclusion Our findings suggest that XRCC4 knockdown sensitizes TNBC cells to ionizing radiation, and could be considered as a novel predictor of radiosensitivity and a promising target for TNBC.
放疗是一种重要的局部治疗方法，需要提高其对三阴性乳腺癌（TNBC）的疗效。本研究旨在探讨 XRCC4 对 TNBC 放射敏感性的潜在影响。
采用 RNAi 技术建立 XRCC4 敲低的 TNBC 稳定细胞系。MTT 法检测 XRCC4 敲低对细胞增殖的影响。Western blot 和免疫组化法检测蛋白表达。克隆形成实验检测 XRCC4 敲低对 TNBC 细胞辐射后集落形成能力的影响。彗星实验检测 XRCC4 沉默对电离辐射下 DNA 修复活性的影响。此外，我们基于 TCGA 数据库中的数据进行了生存分析。
慢病毒介导的 shRNA 敲低 XRCC4 对 TNBC 细胞的增殖没有显著影响。XRCC4 敲低可显著提高 TNBC 细胞对电离辐射的敏感性。XRCC4 敲低组的 DNA 损伤水平增加，表明 XRCC4 缺失细胞的修复延迟明显。临床样本分析显示，不同 TNBC 患者的 XRCC4 表达存在差异。此外，生存分析显示，XRCC4 高表达与 TNBC 患者放疗后无进展生存期不良显著相关。结论：我们的研究结果表明，XRCC4 敲低可增强 TNBC 细胞对电离辐射的敏感性，可作为放射敏感性的新型预测因子和 TNBC 的有前途的治疗靶点。
