Background/Objectives: The lack of canonical biomarkers and strategies to target radioresistance contribute to poor patient outcomes in triple-negative breast cancer (TNBC). Identifying and targeting novel radioresistance genes will benefit in enhancing radiotherapy response and treatment outcomes in TNBC patients. Methods: A genome-wide CRISPR screen was performed to identify radioresistance genes in the TNBC cell line. An in vitro clonogenic assay was used to assess the antiproliferative effects of Artemis knockout or pharmacologic inhibition of Artemis, either alone or in combination with RT. Tumor doubling time and animal survival were assessed using an in vivo xenograft model. RNA-seq analysis was performed to identify genes and pathways deregulated under Artemis knockout conditions, both alone and in combination with RT. Cellular senescence was evaluated using a β-galactosidase assay. Results: Our CRISPR screen identified Artemis as a top hit in RT-treated TNBC cells, whose depletion led to radiosensitization in TNBC. Artemis knockout significantly reduced cell proliferation and enhanced the antiproliferative effects of RT in vitro. Compared to mice-bearing control MDA-MB-231 xenografts, Artemis knockout exhibited prolonged survival that was further enhanced with RT. Bulk RNA-sequencing indicated that the antiproliferative and radiosensitization effects of Artemis depletion were mediated by the activation of cellular senescence which was confirmed with a β-galactosidase assay. Conclusions: Taken together, our results highlight the critical role of Artemis in TNBC cell proliferation and response to radiation. Our findings identify Artemis as a potential biomarker indicative of sensitivity to radiation and a putative target that could be inhibited to enhance the efficacy of RT in TNBC.
背景/目的：三阴性乳腺癌（TNBC）因缺乏规范的生物标志物及针对放射抵抗的有效策略，导致患者预后不佳。识别并靶向新型放射抵抗基因将有助于提升TNBC患者的放疗反应及治疗效果。方法：本研究通过全基因组CRISPR筛选鉴定TNBC细胞系中的放射抵抗基因。采用体外克隆形成实验评估Artemis基因敲除或其药物抑制（单独或联合放疗）的抗增殖效应。通过体内异种移植模型评估肿瘤倍增时间及动物生存情况。利用RNA测序分析鉴定Artemis敲除条件下（单独或联合放疗）失调的基因与通路，并采用β-半乳糖苷酶实验评估细胞衰老状态。结果：CRISPR筛选发现Artemis是放疗处理的TNBC细胞中最显著的靶点，其缺失可增强TNBC细胞的放射敏感性。Artemis敲除显著抑制细胞增殖，并在体外增强放疗的抗增殖作用。与携带对照MDA-MB-231异种移植瘤的小鼠相比，Artemis敲除联合放疗可进一步延长小鼠生存期。批量RNA测序表明，Artemis缺失的抗增殖与放射增敏效应通过激活细胞衰老通路介导，该结果经β-半乳糖苷酶实验验证。结论：本研究结果共同揭示了Artemis在TNBC细胞增殖及放疗反应中的关键作用。Artemis可作为预测放疗敏感性的潜在生物标志物，并有望成为通过抑制其功能以增强TNBC放疗疗效的靶点。
Artemis (DCLRE1C) Acts as a Target to Enhance Radiotherapy Response in Triple-Negative Breast Cancer
肿瘤(癌症)患者之家