Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Department of Thoracic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Int J Radiat Oncol Biol Phys. 2020 Nov 1;108(3):758-769. doi: 10.1016/j.ijrobp.2020.05.005. Epub 2020 May 12.
Tumor resistance to radiation therapy is a therapeutic challenge in the treatment of patients with non-small cell lung cancer. Cyclin-dependent kinase 5 (CDK5) has been proposed to participate in cell proliferation, migration and invasion, drug resistance, and immune evasion. However, the functions and regulatory mechanisms of CDK5 in lung cancer radioresistance have not been investigated.
DNA damage response and repair were measured by neutral comet assay and γ-H2AX and Rad51 foci staining. The biological functions of CDK5 in lung cancer radioresistance were investigated with clonogenic survival assays and xenograft tumor models. Small interfering RNAs and short hairpin RNAs were used to knock down CDK5 in A549 and H1299 cells. The effects of CDK5 depletion on the tumorigenic behaviors of lung cancer cells were evaluated in vitro and in vivo. Gene expression was examined by RNA-seq and quantitative real-time polymerase chain reaction.
We report that CDK5 depletion impairs lung cancer progression and radioresistance in vitro and in vivo. Mechanistically, we identify TAZ, a component of the Hippo pathway, as a critical downstream effector of CDK5. Loss of CDK5 downregulates TAZ expression and attenuates Hippo signaling activation. Importantly, we provide evidence that TAZ is the major effector mediating the biological functions of CDK5 in lung cancer.
These results illustrate that CDK5 activates Hippo signaling via TAZ to participate in tumorigenesis and radioresistance, suggesting that CDK5 may be a promising radiosensitization target for the treatment of lung cancer.
肿瘤对放射治疗的抵抗是治疗非小细胞肺癌患者的一个治疗挑战。细胞周期蛋白依赖性激酶 5（CDK5）被提出参与细胞增殖、迁移和侵袭、耐药性和免疫逃逸。然而，CDK5 在肺癌放射抵抗中的功能和调节机制尚未得到研究。
通过中性彗星试验和 γ-H2AX 和 Rad51 焦点染色来测量 DNA 损伤反应和修复。通过集落形成存活测定和异种移植肿瘤模型来研究 CDK5 在肺癌放射抵抗中的生物学功能。使用小干扰 RNA 和短发夹 RNA 敲低 A549 和 H1299 细胞中的 CDK5。在体外和体内评估 CDK5 耗竭对肺癌细胞致瘤行为的影响。通过 RNA-seq 和实时定量聚合酶链反应检查基因表达。
我们报告 CDK5 耗竭可损害肺癌的进展和体内外的放射抵抗。在机制上，我们确定 TAZ 是 Hippo 通路的一个组成部分，是 CDK5 的关键下游效应因子。CDK5 的缺失下调了 TAZ 的表达并减弱了 Hippo 信号的激活。重要的是，我们提供了证据表明 TAZ 是介导 CDK5 在肺癌中发挥生物学功能的主要效应因子。
这些结果表明 CDK5 通过 TAZ 激活 Hippo 信号参与肿瘤发生和放射抵抗，提示 CDK5 可能是治疗肺癌的有前途的放射增敏靶标。
