肺鳞癌患者血浆外泌体中蛋白标志物的诊断价值

Diagnostic value of protein markers in plasma exosomes of lung squamous cell carcinoma

目的研究肺鳞癌患者治疗前血浆中外泌体所携带的肿瘤相关蛋白的表达特征，并分析其作为临床诊断标志物的价值。方法使用超速离心法收集2例肺鳞癌患者治疗前血浆和2例正常对照血浆中的外泌体，采用蛋白质组学方法分析外泌体的蛋白表达谱，挑选候选分子，采用酶联免疫吸附法在15例肺鳞癌患者和15例正常对照者血浆外泌体中进行验证。结果经过电镜和纳米颗粒追踪技术收集到高质量的外泌体，计数结果显示，2例肺鳞癌患者标本分布于45～135 nm的颗粒数目分别为7.89×10^11个/ml和9.71×10^11个/ml，明显高于2例正常对照者（分别为2.76×10^11个/ml和1.41×10^11个/ml）。蛋白质组学分析显示，肺鳞癌患者外泌体中携带的蛋白信息与正常人有差异，部分蛋白与肺鳞癌发生发展中的重要功能相关。挑选外泌体中14－3－3ζ作为进一步验证的标志物，得到受试者工作特征曲线下面积为0.68，灵敏度为60.0%，特异度为80.0%，提示其可作为肺鳞癌的诊断标志物。结论肺鳞癌患者血浆中的外泌体计数及其携带与肿瘤发生、发展密切相关的蛋白14－3－3ζ，可用于肺鳞癌的辅助诊断。

ObjectiveTo investigate the tumor-associated protein molecules carried by plasma exosomes of patients with lung squamous cell carcinoma before treatment and analyze their value as clinical markers.MethodsExosomes from 2 patients with lung squamous cell carcinoma before treatment and 2 healthy controls were collected by ultracentrifugation. Proteomics was applied to analyze the protein expression profiles of exosomes. Candidate molecules were verified in another 30 exosomes samples from lung squamous cell carcinoma and healthy controls using enzyme-linked immunosorbent assay （ELISA）.ResultsElectron microscopy and particle-counting assay showed that high-quality exosomes were collected. The number of exosomes distributed from 45 to 135 nm in 2 cases of lung cancer patients were 7.89×1011/ml and 9.71×1011/ml, respectively, significantly higher than 2.76×1011/ml and 1.41×1011/ml in healthy controls. Proteomic analysis showed that proteins of exosomes in lung squamous cell carcinoma patients were very different from those of healthy controls, and some proteins are related to important functions in tumor progression. 14-3-3ζ from exosomes was selected and further verified as a marker, and the area under the receiver operating characteristic curve （ROC） was 0.68. The sensitivity and specificity of 14-3-3 ζ from exosomes were 60.0% and 80.0%, respectively, suggested that it could be used as a diagnostic marker for lung squamous cell carcinoma.ConclusionThe exosome counts in plasma and the protein molecules from exosomes, such as 14-3-3ζ, are closely related to the tumorigenesis, which can be used to assist clinical diagnosis of lung squamous cell carcinoma patients.