The identification of proteins differentially expressed between cancer and normal cells is vital for the development of cancer diagnostics, therapeutics and vaccines. Using a ProteinChip Biomarker System (Ciphergen Biosystems, Fremont, CA) which combines ProteinChip technology with time-of-flight mass spectrometry, we have developed a simple method to screen and identify differentially secreted proteins from tumor cell lines. Mass spectra of the range of proteins secreted from normal B-cells were generated along with those secreted from Epstein-Barr virus transformed B-cells. A mass peak at m/z = 4972.1 that was highly over-represented in the transformed B-cell line was chosen for identification and purified by reversed phase chromatography with concomitant monitoring of fractions by SELDI-TOF MS. The resulting purified protein was digested with trypsin and the peptide masses derived from the SELDI-TOF spectrum were used to search the public databases for protein identification. Fragment matching of the resulting peptides identified the protein as thymosin beta-4. Using LC-electrospray ionization MS/MS, the identity of this protein was confirmed. Thymosin beta-4 is a known marker in LCLs establishing the utility of this method to discover and identify proteins differentially expressed between cancers and their matched normal counterparts.

中文翻译：

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使用ProteinChip阵列表面增强的激光解吸/电离飞行时间质谱（SELDI-TOF MS）来鉴定胸腺素β-4，这是一种来自淋巴母细胞样细胞系的差异分泌蛋白。

鉴定癌症和正常细胞之间差异表达的蛋白质对于癌症诊断，治疗和疫苗的开发至关重要。使用将ProteinChip技术与飞行时间质谱相结合的ProteinChip生物标志物系统（Ciphergen Biosystems，加利福尼亚州弗里蒙特），我们开发了一种简单的方法，可以从肿瘤细胞系中筛选和鉴定差异分泌的蛋白。产生了正常B细胞​​分泌的蛋白质范围的质谱图，以及从爱泼斯坦-巴尔病毒转化的B细胞分泌的蛋白质的质谱图。选择m / z = 4972.1的质量峰，该峰在转化的B细胞系中高度过量表达，以进行鉴定，并通过反相色谱法进行纯化，并同时通过SELDI-TOF MS监控馏分。用胰蛋白酶消化所得的纯化蛋白，并使用从SELDI-TOF谱得到的肽段搜索公共数据库以进行蛋白鉴定。所得肽的片段匹配鉴定该蛋白质为胸腺素β-4。使用LC电喷雾电离MS / MS，确认了该蛋白质的身份。胸腺素β-4是LCL中的已知标记物，确立了该方法的实用性，可发现和鉴定在癌症及其匹配的正常对应物之间差异表达的蛋白质。