Department of Otorhinolaryngology, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
Department of Biochemistry and Molecular Biology, Molecular Medicine and Cancer Research Center, Chongqing Medical University, Chongqing, 400016, China.
Int J Biol Sci. 2020 Jan 1;16(3):408-419. doi: 10.7150/ijbs.37302. eCollection 2020.
Radiotherapy plays a major role in the management of nasopharyngeal carcinoma (NPC). However, the radioresistant cells limit its efficiency and drive recurrence inside the irradiated tumor volume leading to poor outcome for patients. To illuminate the signal pathway involved in the radioresistance and evaluate the potential for predicting NPC response to radiotherapy, we established the radioresistant NPC cell line (CNE2-RR) derived from NPC cell line CNE2 by gradually increased the radiation dose (total 60 Gy), and the radioresistance of CNE2-RR cells was evaluated by the colony formation, FCM and comet assays. Furthermore, comparison of established CNE2-RR cell line to parental cell line found the homologous recombination repair (HRR) proteins differences involved in NPC radioresistance. In addition, the differentially expressed proteins were further validated by western blotting, immunofluorescence and IHC in tumor xenografs and radioresistant NPC tissues. Furthermore, the correlation of HRR proteins expression levels with NPC radioresistance were evaluated. The results showed that the upregulation of HRR proteins were significantly correlated with NPC radioresistance. In addition, using the Youden Index cutoff value, a panel of the HRR proteins analyses revealed a sensitivity of 70%, specificity of 72%. Furthermore, silencing NFBD1 enhanced the radiosensitivity of CNE2-RR cells by impairing IR-inducing γ-H2AX and HR proteins foci formation. These results suggest that controlling the HRR signaling pathway may hold promise to overcome NPC radioresistance.
放射治疗在鼻咽癌（NPC）的治疗中起着重要作用。然而，放射抵抗细胞限制了其疗效，并在照射肿瘤体积内引发复发，导致患者预后不良。为了阐明放射抵抗涉及的信号通路，并评估其预测 NPC 对放射治疗反应的潜力，我们通过逐渐增加辐射剂量（总剂量 60Gy），从 NPC 细胞系 CNE2 中建立了放射抵抗 NPC 细胞系（CNE2-RR），并通过集落形成、FCM 和彗星试验评估了 CNE2-RR 细胞的放射抵抗能力。此外，将建立的 CNE2-RR 细胞系与亲本细胞系进行比较，发现涉及 NPC 放射抵抗的同源重组修复（HRR）蛋白差异。此外，通过肿瘤异种移植和放射抵抗 NPC 组织中的 Western 印迹、免疫荧光和免疫组化进一步验证了差异表达蛋白。此外，还评估了 HRR 蛋白表达水平与 NPC 放射抵抗之间的相关性。结果表明，HRR 蛋白的上调与 NPC 放射抵抗显著相关。此外，使用 Youden 指数截断值，HRR 蛋白分析的面板显示出 70%的敏感性和 72%的特异性。此外，沉默 NFBD1 通过损害 IR 诱导的 γ-H2AX 和 HR 蛋白焦点形成，增强了 CNE2-RR 细胞的放射敏感性。这些结果表明，控制 HRR 信号通路可能有希望克服 NPC 放射抵抗。
