Section for Translational Surgical Oncology and Biobanking, Department of Surgery, University of Lübeck and University Medical Center Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
Institute of Clinical Biochemistry and Pathobiochemistry, Leibniz Center for Diabetes Research, German Diabetes Center at the Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.
Cell Mol Life Sci. 2018 Jan;75(2):323-334. doi: 10.1007/s00018-017-2631-9. Epub 2017 Aug 28.
Colorectal cancer (CRC) is one of the most frequent malignancies in the Western world. Early tumor detection and intervention are important determinants on CRC patient survival. During early tumor proliferation, dissemination and angiogenesis, platelets store and segregate proteins actively and selectively. Hence, the platelet proteome is a potential source of biomarkers denoting early malignancy. By comparing protein profiles of platelets between healthy volunteers (n = 12) and patients with early- (n = 7) and late-stage (n = 5) CRCs using multiplex fluorescence two-dimensional gel electrophoresis (2D-DIGE), we aimed at identifying differentially regulated proteins within platelets. By inter-group comparisons, 94 differentially expressed protein spots were detected (p < 0.05) between healthy controls and patients with early- and late-stage CRCs and revealed distinct separations between all three groups in principal component analyses. 54 proteins of interest were identified by mass spectrometry and resulted in high-ranked Ingenuity Pathway Analysis networks associated with Cellular function and maintenance, Cellular assembly and organization, Developmental disorder and Organismal injury and abnormalities (p < 0.0001 to p = 0.0495). Target proteins were validated by multiplex fluorescence-based Western blot analyses using an additional, independent cohort of platelet protein samples [healthy controls (n = 15), early-stage CRCs (n = 15), late-stage CRCs (n = 15)]. Two proteins-clusterin and glutathione synthetase (GSH-S)-featured high impact and were subsequently validated in this independent clinical cohort distinguishing healthy controls from patients with early- and late-stage CRCs. Thus, the potential of clusterin and GSH-S as platelet biomarkers for early detection of CRC could improve existing screening modalities in clinical application and should be confirmed in a prospective multicenter trial.
结直肠癌（CRC）是西方世界最常见的恶性肿瘤之一。早期肿瘤的检测和干预是 CRC 患者生存的重要决定因素。在早期肿瘤增殖、扩散和血管生成过程中，血小板主动且选择性地储存和分隔蛋白质。因此，血小板蛋白质组是表示早期恶性肿瘤的潜在生物标志物来源。通过使用多重荧光二维凝胶电泳（2D-DIGE）比较 12 名健康志愿者（n=12）和早期（n=7）及晚期（n=5）CRC 患者血小板的蛋白质谱，我们旨在鉴定血小板中差异表达的蛋白质。通过组间比较，在健康对照组和早期及晚期 CRC 患者之间检测到 94 个差异表达的蛋白质斑点（p<0.05），并且所有三组在主成分分析中均有明显的分离。通过质谱鉴定了 54 个感兴趣的蛋白质，这些蛋白质通过高排名的 Ingenuity Pathway Analysis 网络与细胞功能和维持、细胞组装和组织、发育障碍以及机体损伤和异常（p<0.0001 至 p=0.0495）相关。使用另一个独立的血小板蛋白质样本队列[健康对照组（n=15）、早期 CRC 组（n=15）、晚期 CRC 组（n=15）]，通过基于多重荧光的 Western blot 分析验证了靶蛋白。两种蛋白质-簇蛋白和谷胱甘肽合成酶（GSH-S）具有高影响力，随后在这个独立的临床队列中进行了验证，可将健康对照组与早期和晚期 CRC 患者区分开来。因此，簇蛋白和 GSH-S 作为血小板生物标志物用于早期检测 CRC 的潜力可能会改善现有临床应用中的筛选方法，并且应该在前瞻性多中心试验中得到证实。
