Crizotinib Fails to Enhance the Effect of Radiation in Head and Neck Squamous Cell Carcinoma Xenografts.
Crizotinib Fails to Enhance the Effect of Radiation in Head and Neck Squamous Cell Carcinoma Xenografts.
复制标题
克唑替尼未能增强放射治疗头颈鳞状细胞癌异种移植物的效果。
作者：
A. Baschnagel;S. Galoforo;B. Thibodeau;Samreen I. Ahmed;Sonali Nirmal;J. Akervall;G. Wilson
目的
间质上皮转化因子（MET）是一种受体酪氨酸激酶，在头颈部鳞状细胞癌（HNSCC）中表达，参与肿瘤进展并与预后不良相关。克唑替尼（一种强效ATP竞争性激酶抑制剂）可以抑制MET。我们在临床前HNSCC模型中检查了克唑替尼和放射联合治疗的效果。
材料和方法
对九个HNSCC细胞系进行了MET表达、拷贝数扩增和突变状态筛选。采用克隆形成存活试验评估克唑替尼和放射的体外效应。用蛋白质印迹和受体酪氨酸激酶阵列评估MET信号蛋白。使用UT-SCC-14和UT-SCC-15口腔舌异种移植物的肿瘤生长延迟实验来评估体内肿瘤放射敏感性。
结果
所有九种HNSCC细胞系均表现出不同程度的MET蛋白和RNA表达。不存在MET拷贝数增加。MET在体内外照射后均有表达。克唑替尼单独给药可抑制MET磷酸化，并在体外抑制细胞生长，但不能抑制下游信号蛋白MAPK、AKT或c-SRC的磷酸化。当与体外辐射联合使用时，克唑替尼仅在一种细胞系中表现出辐射增强作用。克唑替尼在作为异种移植物生长的UT-SCC-14或UT-SCC-15肿瘤中均未增强放射效应。
结论
MET在HNSCC细胞系中过表达，然而，在该HNSCC模型中，克唑替尼未能增强辐射反应，也未能抑制MET下游信号蛋白。
AIM
Mesenchymal-epithelial transition factor (MET), a receptor tyrosine kinase, is expressed in head and neck squamous cell carcinomas (HNSCC) and is involved in tumor progression and associated with poor prognosis. MET can be inhibited by crizotinib, a potent ATP-competitive kinase inhibitor. We examined the effects of combining crizotinib and radiation in a pre-clinical HNSCC model.
MATERIALS AND METHODS
Nine HNSCC cell lines were screened for MET expression, copy-number amplification and mutational status. The in vitro effects of crizotinib and radiation were assessed with clonogenic survival assays. MET signaling proteins were assessed with western blot and receptor tyrosine kinase array. Tumor growth-delay experiments with UT-SCC-14 and UT-SCC-15 oral tongue xenografts were used to assess in vivo tumor radiosensitivity.
RESULTS
All nine HNSCC cell lines showed a varying degree of MET protein and RNA expression. Increased MET copy number was not present. MET was expressed after irradiation both in vitro and in vivo. Crizotinib alone inhibited phosphorylation of MET and inhibited cell growth in vitro but did not inhibit phosphorylation of downstream signaling proteins: MAPK, AKT or c-SRC. When combined with radiation in vitro, crizotinib demonstrated radiation enhancement in only one cell line. Crizotinib did not enhance the effect of radiation in either UT-SCC-14 or UT-SCC-15 tumors grown as xenografts.
CONCLUSION
MET is overexpressed in HNSCC cell lines, however, crizotinib failed to enhance the radiation response and failed to inhibit MET downstream signaling proteins in this HNSCC model.