食管癌相关血清小分子蛋白谱的初步研究

A Preliminary Study of ESCC Related Protein Profiling/Peptides Pattern

目的 分析食管鳞癌血浆蛋白表达谱改变，筛选恰当的蛋白分类芯片用于建立食管鳞癌血清标志诊断模型。方法 血浆蛋白经离子交换，按不同pH值范围预分离为6个组份，各组份分别在弱阳离子交换型和铜离子螯和型等两类蛋白芯片上分选与富集，经表面增强激光解吸离子化飞行时间质谱技术分析食管鳞癌差异表达蛋白。分析5例食管鳞癌和2冽性别、年龄匹配的对照血清，初步获得弱阳离子交换型和铜离子螯和型蛋白芯片表达图谱。结果血浆蛋白经不同离子交换柱预分离和不同蛋白分类捕获芯片富集，在相对分子质量0～50000范围内，弱阳离子交换型和铜离子螯和型蛋白芯片上检测到近百种差异蛋白峰，其中部分差异峰具有统计学意义（P〈0．05）。结论 血浆蛋白经不同pH区段预分离和分类捕获后可降低高丰度蛋白干扰，提高负载疾病信息的低丰度蛋白／肽段显示度。弱阳离子交换型和铜离子螯和型蛋白芯片结合蛋白可呈现食管癌术前与术后，以及食管癌和健康对照者的差异表达谱。初步研究提示，食管癌外周血浆存在肿瘤候选标志分子（谱）。

Objective In order to maximize the success of discovering and eventually isolating potential esophageal squamous cell carcinoma （ESCC） biomarkers in serum,a fractionation and different protein chip chemistries approaches prior to SELDI analysis were developed. Methods Five pairs of pre/post-operation serum of ESCC and 2 gender-/age-matched healthy controls were applied to anion exchange resin. The proteins were eluted with differ ent pH buffers and organic solvents. Different fractions were collected and applied to 2 kinds of protein chip chemistries （metal binding-IMAC3 Cu and weak cationic exchange, WCX）. Six fractions for each specimen were analyzed in duplicate by SELDI-TOF-MS technolo gy. Results The process produced approximately 115 peaks compared to 50 to 90 peaks with un-fractionated ESCC. The proteins or peptide peaks were detected at the molecular range of 0 to 50 000, some of them were significantly different between ESCC and controls （P〈0. 05）. Conclusion Thie pilot study demonstrates that fractionation prior to SELDI analysis could enhance the potential of uncovering low abundant protein/peptide that might have been masked by high abundant proteins present in the un-fractionated sample. The fractionation approach also benefits development of strategies for the purification of selected biomarkers.