Comparative Analysis of the Protein Profiles from Primary Gastric Tumors and Their Adjacent Regions: MAWBP Could Be a New Protein Candidate Involved in Gastric Cancer

The study of tumor biomarkers is generally facilitated by the adoption of proteomic strategies. With
limitations of techniques and individual varieties of biological samples, the biomarkers for gastric cancer
(GC) have not reached a common agreement derived from the proteomic investigations. Herein, we
reported a new set of data for screening the biomarkers from the gastric tissues, on the basis of the
proteomic strategy developed in our laboratory. Ten pairs of the clinic samples were collected and
treated with protein extraction. The gastric proteins were well-resolved by 2-DE, and the GC-associated
proteins were identified by MALDI-TOF/TOF MS following image analysis, including 12 up-regulated
and 13 down-regulated unique ones. MAWBP was found to be one of the new GC proteins which
appeared with lower expression in the GC tissues. We expanded a systematical examination to deeply
pursue the relevance between MAWBP and GC. Quantitatively, we measured the expression of MAWBP
with Western blot and Real-Time PCR. Extendedly, we estimated the existence of MAWBP with
immunohistochemical staining in a large number of the GC cases. Specifically, we inquired whether
MAWD, a protein with high affinity to MAWBP, could coexpress and interact with MAWBP in vivo. On
the basis of all the results, we concluded that MAWBP could be a new GC-related protein even though
its physiological roles remain unexplored.
Keywords: Gastric cancer • MAWBP • MAWD • proteomics • tissue microarray

肿瘤生物标志物的研究通常可借助蛋白质组学策略推进。但受限于实验技术瓶颈与生物样本的个体差异，目前基于蛋白质组学研究得到的胃癌（Gastric Cancer, GC）相关生物标志物尚未形成统一共识。本研究基于本实验室开发的蛋白质组学方法，报道了一套全新的胃癌组织生物标志物筛选数据集。我们收集了10对临床样本并完成蛋白质提取。胃癌组织蛋白经双向凝胶电泳（2-DE）实现高效分离，经图像分析后，通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF/TOF MS）鉴定得到胃癌相关差异蛋白，其中包含12个上调表达、13个下调表达的独特蛋白。研究发现MAWBP是一种新型胃癌相关蛋白，在胃癌组织中呈低表达状态。为深入探究MAWBP与胃癌的相关性，我们开展了系统性实验：通过蛋白质免疫印迹（Western blot）与实时定量PCR（Real-Time PCR）对MAWBP的表达水平进行定量检测；采用免疫组化染色（immunohistochemical staining）技术，在大量胃癌病例样本中评估MAWBP的表达情况；具体而言，我们还探究了与MAWBP具有高亲和力的蛋白MAWD是否可在体内与MAWBP发生共表达并产生相互作用。综合所有实验结果，我们认为MAWBP可作为一种新型胃癌相关蛋白，尽管其具体生理功能仍有待阐明。
关键词：胃癌 • MAWBP • MAWD • 蛋白质组学 • 组织微阵列（tissue microarray）