A high-quality secretome of A549 cells aided the discovery of C4b-binding protein as a novel serum biomarker for non-small cell lung cancer.
Cancer secretomes are a promising source for biomarker discovery. The analysis of cancer secretomes still faces some difficulties mainly related to the intracellular contamination, which hinders the qualification and follow-up validations. This study aimed to establish a high-quality secretome of A549 cells by using the cellular proteome as a reference and to test the merits of this refined secretome for biomarker discovery for non-small cell lung cancer (NSCLC). Using one-dimensional gel electrophoresis followed by liquid-chromatography tandem mass spectrometry, we comprehensively investigated the secretome and the concurrent cellular proteome of A549 cells. A high-quality secretome consisting of 382 proteins was refined from 889 initial secretory proteins. More than 85.3% of proteins were annotated as secreted and 76.8% as extracellular or membrane-bound. The discriminative power of the lung-cancer associated secretome was confirmed by gene expression and serum proteomic data. The elevated level of C4b-binding Protein (C4BP) in NSCLC blood was verified by enzyme-linked immunosorbent assays (ELISA, p = 6.07e-6). Moreover, the serum C4BP level in 89 patients showed a strong association with the clinical staging of NSCLC. Our reference-experiment-driven strategy is simple and widely applicable, and may facilitate the identification of novel promising biomarkers of lung cancer.
Department of Thoracic Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.
Xiaoyang
X
Luo
Yansheng
Y
Liu
Rui
R
Wang
Haichuan
H
Hu
Rong
R
Zeng
Haiquan
H
Chen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis / Q000097:blood / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000097:blood* / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D016000:Cluster Analysis; D050716:Complement C4b-Binding Protein / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009367:Neoplasm Staging; D020543:Proteome / Q000032:analysis / Q000378:metabolism*; D011786:Quality Control; D054928:Validation Studies as Topic
D014408:Biomarkers, Tumor; D050716:Complement C4b-Binding Protein; D020543:Proteome