Chen Xue, Zhang Qi, Luo Youjun, Gao Caixia, Zhuang Xibing, Xu Guoxiong, Qiao Tiankui
Department of Oncology, Jinshan Hospital, Medical Center of Fudan University.
Department of Center laboratory, Jinshan Hospital, Fudan University, Shanghai, People's Republic of China.
Onco Targets Ther. 2016 Oct 21;9:6511-6518. doi: 10.2147/OTT.S116629. eCollection 2016.
Irradiation resistance appears as local recurrence and distant metastasis in advanced stages of non-small cell lung cancer (NSCLC). High-dose irradiation combined with immunotherapy improved overall survival and local control of NSCLC. This study explored the underlying molecular mechanism by which the effect of high-dose irradiation plus toll-like receptor 9 (TLR9) agonist CpG oligodeoxynucleotide (CpG ODN) 7909 on NSCLC.
NSCLC H460 cells were exposed to constant high-dose irradiation (6.37 Gy) in irradiation (IR) group and the irradiation plus CpG group. Gene expression was assessed using quantitative reverse transcriptase-polymerase chain reaction and Western blot. Knockdown of nuclear factor kappa B (NF-κB) p65 expression was conducted using p65 siRNA.
Expression of programmed death-ligand 1 (PD-L1) mRNA was significantly decreased in IR combined with CpG ODN 7909 group compared with the control or IR-alone groups (<0.05). TLR9 expression was also obviously increased in the combination group compared with the control (<0.05). Moreover, expression of NF-κB p65 was apparently reduced in the combination group compared with the control (<0.05). However, expression of PD-L1 was significantly decreased after knockdown of p65 in IR group (<0.05), but increased in the combination group (<0.05) and slightly increased in CpG ODN-alone group (<0.05), which was opposite to that without p65 knockdown group.
This study demonstrated that radiotherapy combined with CpG ODN 7909 was able to downregulate PD-L1 expression through inhibition via the NF-κB signaling pathway.
在非小细胞肺癌（NSCLC）晚期，辐射抗性表现为局部复发和远处转移。高剂量辐射联合免疫疗法可改善NSCLC的总生存期和局部控制。本研究探讨了高剂量辐射加 Toll 样受体 9（TLR9）激动剂 CpG 寡脱氧核苷酸（CpG ODN）7909 对 NSCLC 作用的潜在分子机制。
将 NSCLC H460 细胞暴露于照射（IR）组的恒定高剂量辐射（6.37 Gy）以及照射加 CpG 组。使用定量逆转录聚合酶链反应和蛋白质免疫印迹法评估基因表达。使用 p65 小干扰 RNA（siRNA）敲低核因子κB（NF-κB）p65 的表达。
与对照组或单纯照射组相比，IR 联合 CpG ODN 7909 组中程序性死亡配体 1（PD-L1）mRNA 的表达显著降低（<0.05）。与对照组相比，联合组中 TLR9 的表达也明显增加（<0.05）。此外，与对照组相比，联合组中 NF-κB p65 的表达明显降低（<0.05）。然而，IR 组中 p65 敲低后 PD-L1 的表达显著降低（<0.05），但联合组中升高（<0.05），CpG ODN 单独处理组中略有升高（<0.05），这与未敲低 p65 的组相反。
本研究表明，放疗联合 CpG ODN 7909 能够通过抑制 NF-κB 信号通路下调 PD-L1 的表达。
