胃癌基因表达谱和蛋白质表达谱的分析研究

Analysis of human gastric cancer by transcriptome and proteome profiling

目的从转录组水平和蛋白质组水平寻找胃癌组织与正常胃组织间的差异表达基因和蛋白。方法应用含有14592个已知基因及表达序列标签的cDNA表达谱芯片获取基因表达谱信息．50％以上样本中Cy3／Cy5荧光强度比大于或等于2和小于或等于0．5的基因分别为在胃癌中表达上调或下调的基因。采用双向凝胶电泳（2-DE）分离32例经手术切除的胃癌患者的胃癌组织和正常胃组织总蛋白．对差异表达蛋白质点利用基质辅助激光解析电离飞行时间质谱（MALDI—TOF—MS）进行分析．获取肽质量指纹图谱（PMF）。同时搜索SWISS-PROT数据库鉴定蛋白质。结果与正常组织相比．胃癌组织中差异表达基因共有387个，其中表达上调的有149个基因．上调超过3倍的有29个基因：表达下调的有238个基因．其中下调超过5倍的有21个基因。在蛋白质水平鉴定了15个差异表达蛋白．在肿瘤组织中高表达的有10个．其余5个在肿瘤组织中低表达。胃癌中过表达的基凶与蛋白产物主要与细胞骨架运动、细胞增殖及信号传导有关．表达下调的则主要与细胞免疫防御、毒理代谢有关。结论从转录组水平和蛋白质组水平对胃癌基因表达谱进行分析．不仅有助于从分子水平全方位理解胃癌的发病机制及生物学特性．同时也有助于进一步发现新的胃癌相关标志物和基因治疗的靶点。

Objective To screen differential expression genes and proteins at transcriptome and proteome levels between human gastric cancer tissue and corresponding normal mucosa. Methods Fresh-frozen gastric cancers were collected from patients treated at Ruijin Hospital. A total of 22 pairs of gastric cancer tissues and the corresponding noncancerous mucosa were analyzed. Commercially available eDNA microarray with 14 592 genes/ESTs was used. Genes were considered to be up- or down-regulated when the intensity ratio Cy3/Cy5 was ≥2 or ≤0.5 in over 50% samples （P〈0.05）. Immobilized pH gradient（IPG）-based 2-DE was applied to separate the total proteins of gastric cancer tissue and paired normal tissue. After staining and analysis by software, the differential expression proteins were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry （MALDI-TOF-MS） or MALDI-TOF-TOF-MS. Results As compared with corresponding noncancerous tisssue, there were totally 149 up-regulating genes/ESTs and 238 down-regulating genes/ ESTs in gastric cancer, including 29 genes with 3-fold over-expression ratio and 21 genes with 5-fold under-expression. Fifteen protein spots were identified successfully, among whom there were ten overexpressed and five under-expressed proteins in gastric cancer tissue compared with normal tissue. Most of over-expressed genes and proteins were related to cell motility, cell proliferation, signal transduction, while those under-expressed genes and proteins were related to defense response, toxieoid metabolism. Conclusion Studying gastric cancer at transcriptome and proteome levels can help demonstrate tumorigenesis and biological characteristics of gastric cancer comprehensively and provide powerful tools to find new biomarkers associated with gastric cancer and therapy targets.