结直肠癌转移动物模型血清中几种蛋白变化的观察

Monitoring changes of serum protein markers in metastatic colorectal carcinoma model

目的建立可视化结直肠癌转移模型,并应用血清蛋白质组学技术分析可视化结直肠癌转移模型血清蛋白质的变化。方法用 pEGFP-N1绿色荧光蛋白基因转染具有转移能力的 SW480细胞株,在裸鼠皮下接种成瘤后,再原位接种于裸鼠右半结肠,利用整体荧光成像系统观察结直肠癌原位成瘤及发生转移的情况。同时采集裸鼠原位成瘤后不同转移阶段的血清,进行双向电泳联合时间飞行质谱分析差异蛋白质,观察结直肠癌转移模型裸鼠癌转移前后血清蛋白的变化。结果获得稳定表达绿色荧光蛋白的 SW480-EGFP 细胞株,裸鼠皮下接种成瘤率为100%,原位种植成瘤率为10/10,区域淋巴结转移为10/10,肝转移率为4/10,肺转移率为3/10。通过血清蛋白质组学技术成功鉴定了5个在癌转移发生后血清内显著升高的血清蛋白:结合珠蛋白α链,载脂蛋白 A4,载脂蛋白E,免疫球蛋白κ型 V 区 L 链和转铁蛋白。结论成功建立结直肠癌可视化转移模型,利用不同转移阶段鼠血清进行双向电泳图谱差异分析筛选出5个在癌转移发生后血清中显著升高的蛋白可能是与结直肠癌转移相关的蛋白。

Objective To investigate the changes of several protein markers in a metastatic colorectal carcinoma model by serum proteomic analysis. Methods The pEGFP-N1 plasmid with enhanced expression of green fluorescence protein （EGFP） was transfected into human colon carcinoma cell line SW480 to obtain a stable SW480-EGFP cell line, the SW480-EGFP cells were then injected subcutaneously into nude mice. The harvested tumor cells were implanted orthotopically into the colon of the nude mice. Real-time tumor growth and metastasis formation were visualized by whole-body fluorescent imaging system. Serum samples at different metastatic stages were collected and differential proteomic profiles were investigated by two-dimensional gel electrophoresis （2DE） and matrix-assisted laser absorption/ionization time of flight mass spectrometry （MALDI-TOF MS）. Results The SW480- EGFP cells enabled to express EGFP stably. The rates of subcutaneous and orthotropic tumor formation were 100%. The metastasis rates to local lymph nodes, liver and lung were 100% , 40% and 30% , respectively. Furthermore, 5 differentially expressed proteins were analyzed by serum proteome technologies, including haptoglobin alpha chain, apolipopretein E, apolipoprotein A-IV, Ig kappa chain V region chain L and transferrin. Conclusions Visualized metastatic model of colorectal carcinoma was successfully established. Several differentially expressed serum proteins collected at different stages after the occurrence of metastasis were identified. These differentially expressed proteins may be candidate serum biomarkers for diagnosis and therapeutic evaluation of colorectal carcinoma metastasis.