Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
Hubei Key Laboratory of Precision Radiation Oncology, Wuhan, 430022, China.
J Exp Clin Cancer Res. 2024 Mar 22;43(1):89. doi: 10.1186/s13046-024-03007-w.
The evasion of the immune response by tumor cells through programmed death-ligand 1 (PD-L1) has been identified as a factor contributing to resistance to radioimmunotherapy in lung cancer patients. However, the precise molecular mechanisms underlying the regulation of PD-L1 remain incompletely understood. This study aimed to investigate the role of cyclin-dependent kinase-like 1 (CDKL1) in the modulation of PD-L1 expression and the response to radioimmunotherapy in lung cancer.
The tumorigenic roles of CDKL1 were assessed via cell growth, colony formation, and EdU assays and an in vivo nude mouse xenograft model. The in vitro radiosensitization effect of CDKL1 was evaluated using a neutral comet assay, γH2AX foci formation analysis, and a clonogenic cell survival assay. The protein‒protein interactions were confirmed via coimmunoprecipitation and GST pulldown assays. The regulation of PD-L1 by CDKL1 was evaluated via chromatin immunoprecipitation (ChIP), real-time quantitative PCR, and flow cytometry analysis. An in vitro conditioned culture model and an in vivo C57BL/6J mouse xenograft model were developed to detect the activation markers of CD8 T cells and evaluate the efficacy of CDKL1 overexpression combined with radiotherapy (RT) and an anti-PD-L1 antibody in treating lung cancer.
CDKL1 was downregulated and suppressed the growth and proliferation of lung cancer cells and increased radiosensitivity in vitro and in vivo. Mechanistically, CDKL1 interacted with the transcription factor YBX1 and decreased the binding affinity of YBX1 for the PD-L1 gene promoter, which consequently inhibits the expression of PD-L1, ultimately leading to the activation of CD8 T cells and the inhibition of immune evasion in lung cancer. Moreover, the combination of CDKL1 overexpression, RT, and anti-PD-L1 antibody therapy exhibited the most potent antitumor efficacy against lung cancer.
Our findings demonstrate that CDKL1 plays a crucial role in regulating PD-L1 expression, thereby enhancing the antitumor effects of radioimmunotherapy. These results suggest that CDKL1 may be a promising therapeutic target for the treatment of lung cancer.
肿瘤细胞通过程序性死亡配体 1（PD-L1）的逃逸已被确定为导致肺癌患者对放免治疗产生耐药的因素之一。然而，PD-L1表达调控的精确分子机制仍不完全清楚。本研究旨在探讨周期蛋白依赖性激酶样 1（CDKL1）在调节 PD-L1 表达和对肺癌放免治疗反应中的作用。
通过细胞生长、集落形成和 EdU 检测以及体内裸鼠异种移植模型评估 CDKL1 的致瘤作用。使用中性彗星试验、γH2AX 焦点形成分析和克隆形成细胞存活试验评估 CDKL1 的体外放射增敏作用。通过免疫共沉淀和 GST 下拉试验证实蛋白-蛋白相互作用。通过染色质免疫沉淀（ChIP）、实时定量 PCR 和流式细胞术分析评估 CDKL1 对 PD-L1 的调控。建立体外条件培养模型和体内 C57BL/6J 小鼠异种移植模型，检测 CD8 T 细胞的激活标志物，并评估 CDKL1 过表达联合放疗（RT）和抗 PD-L1 抗体治疗肺癌的疗效。
CDKL1 下调并抑制肺癌细胞的生长和增殖，增加体外和体内的放射敏感性。在机制上，CDKL1 与转录因子 YBX1 相互作用，降低 YBX1 与 PD-L1 基因启动子的结合亲和力，从而抑制 PD-L1 的表达，最终导致 CD8 T 细胞的激活和肺癌免疫逃逸的抑制。此外，CDKL1 过表达、RT 和抗 PD-L1 抗体治疗联合应用对肺癌具有最强的抗肿瘤疗效。
我们的研究结果表明，CDKL1 在调节 PD-L1 表达中起关键作用，从而增强放免治疗的抗肿瘤效果。这些结果表明，CDKL1 可能是治疗肺癌的有前途的治疗靶点。
