Differential Proteomics Study Of Human Colorectal Cancer Genesis And Liver Metastasis

Colorectal cancer is one of the common malignant tumors in our country. A large number of statistical data indicates that the rates of incidence and mortality of the disease in our country have been going up in recent years.Liver metastasis caused severe and fatal effect on patients that underwent radical resecsion for large intestine primary cancer. Early forecast and diagnosis of liver metastasis is the key to improving survival rate for coloretcal cancer patients. Now proteome study methods and techniques, especially two-dimensional electrophoresis (2-DE), provide useful and important support for the research of liver metastasis of coloretcal cancer.【Objective】To study differential proteins and their biological functions associated with colorectal cancer genesis and liver metastasis by proteomics and molecular biology immunohistochemistry techniques.【Methods】The samples of colorectal cancer liver metastasis corresponding to sixteen patients were tested with proteomic analysis. And the highly sensitive two-dimensional differential gel electrophoresis (2-D DIGE) coupled with mass spectrometry (MS) for the identification of proteins differentially expressed in primary cancer lesion and liver metastasis cancer of colorectal cancer were used. The differentially expressed proteins found by 2-D DIGE would be confirmed and validated by immunohistochemistry analyses in those few cases which antibodies were available. Transfection experiment of rectum cancer HR-8348 cells was performed with the differential protein cDNA, and the changes of cell biological behavior was observed.【Results】Significant differences of protein expression were found on two-dimensional electrophoresis. Twenty two differential protein spots were analysed and identified. Human carbonic anhydraseⅡand protein disulfide isomerase were detected in normal colorectal mucosa, but lost in primary cancer lesion. activator protein 2B and transgelin variant were expressed in primary cancer. The expressions of zinc finger protein 64 homolog, guanine nucleotide exchange factor 4, Homo sapiens arginase, homo sapiens glutathione S-transferase A3, tumor necrosis factor alpha-induced protein 9, chain A structure of human glutamate dehydrogenase-apo form, toll-like receptor adaptor molecule 2, ribonucleotide reductase M2 polypeptide increased in the liver metastasis lesion in comparison to those in the primary cancer lesion.After transfection with human carbonic anhydraseⅡcDNA, the HR-8348 cell changed obviously with reduce of drug tolerance. Homo sapiens arginase expressions was assayed by immunohistochemistry method in Colorectal carcinoma associated tissue.【Conclusion】Differential expression of proteins are found among the normal colorectal mucosa ,colorectal cancer genesis and liver metastasis. Loss of carbonic anhydrase II expression and protein disulfide isomerase and enhancement expression of activator protein 2B and transgelin variant are related with colorectal carcinogenesis and colorectal cancer cell biological behavior. Enhancement expression of arginase ,zinc finger protein 64 homolog, guanine nucleotide exchange factor 4 and are related with colorectal cancer liver metastasis. This study of the colorectal cancer proteome represents a step toward a better understanding of the mechanism of the colorectal cancer liver metastasis,and arginase perhaps could be used as biomarkers for colorectal cancer liver metastasis risk...