Monitoring changes of serum protein markers in metastatic colorectal carcinoma model

Abstract

To investigate the changes of several protein markers in a metastatic colorectal carcinoma model by serum proteomic analysis. 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). 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, apolipoprotein E, apolipoprotein A-IV, Ig kappa chain V region chain L and transferrin. 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.