Department of Pharmacy, Xiangya Hospital, Central South University, Changsha 410078, PR China; Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha 410078, PR China; Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha 410078, PR China.
Department of Orthopaedics, the First Affiliated Hospital of the University of South China, PR China.
Biochem Pharmacol. 2021 Aug;190:114616. doi: 10.1016/j.bcp.2021.114616. Epub 2021 May 20.
Anthracycline are inhibitors of topoisomerase II leading to DNA double strand breaks, and it is widely used for treatment of breast cancer. eIF3a is the largest subunit of eukaryotic translation initiation factor 3 (eIF3) and highly expressed in breast cancer. In this study, we investigated the role of eIF3a in DSB DNA repair and the response of breast cancer patients to anthracycline-based chemotherapy.
MTT assay was used to detect anthracycline sensitivity in cell lines. Real-time reverse transcriptase PCR, western blotting and immunofluorescence were performed to assess changes in gene expression levels. Cometassay and end-joining activity assay were conducted to explore the effect of eIF3a in NHEJ repair. Luciferase reporter assay was performed to detect LIG4 5'UTR activity. Immunohistochemistry was used to detect eIF3a, LIG4 and DNA-PKcs expression levels in breast cancer tissues.
The results showed that eIF3a increased cellular response to anthracyclines by regulating DSB repair activity via influencing the expression of LIG4 and DNA-PKcs at translational level. Breast cancer patients with high level of eIF3a or low level of LIG4 or low level of DNA-PKcs had better anthracycline-based chemotherapy prognosis compared. Moreover, Combined expressions of eIF3a, LIG4 and DNA-PKcs could be better to predict PFS in breast cancer patients with anthracycline-based chemotherapy.
Our findings suggest that eIF3a effects anthracycline-based chemotherapy response by regulating DSB DNA repair.
蒽环类药物是拓扑异构酶 II 的抑制剂，导致 DNA 双链断裂，广泛用于乳腺癌的治疗。eIF3a 是真核翻译起始因子 3（eIF3）的最大亚基，在乳腺癌中高度表达。在这项研究中，我们研究了 eIF3a 在 DSB DNA 修复中的作用以及乳腺癌患者对基于蒽环类药物的化疗的反应。
MTT 测定法用于检测细胞系中蒽环类药物的敏感性。实时逆转录 PCR、western blot 和免疫荧光法用于评估基因表达水平的变化。彗星实验和末端连接活性测定用于研究 eIF3a 对 NHEJ 修复的影响。荧光素酶报告基因测定用于检测 LIG4 5'UTR 活性。免疫组织化学用于检测乳腺癌组织中 eIF3a、LIG4 和 DNA-PKcs 的表达水平。
结果表明，eIF3a 通过影响 LIG4 和 DNA-PKcs 的表达来调节 DSB 修复活性，从而增加细胞对蒽环类药物的反应。与低水平的 eIF3a 或高水平的 LIG4 或高水平的 DNA-PKcs 相比，高水平的 eIF3a 或低水平的 LIG4 或低水平的 DNA-PKcs 的乳腺癌患者对基于蒽环类药物的化疗具有更好的预后。此外，eIF3a、LIG4 和 DNA-PKcs 的联合表达可以更好地预测接受基于蒽环类药物的化疗的乳腺癌患者的 PFS。
我们的研究结果表明，eIF3a 通过调节 DSB DNA 修复来影响基于蒽环类药物的化疗反应。
