The Expression Of Thymidine Phosphorylase In Colorectal Cancer And The Empirical Study Of The Therapeutic Efficacy Of 5'-DFUR Combined With Interferon-α To The Mouse Models Of Colorectal Cancer Hepatic Metastasis

BackgroundThymidine phosphorylase(TP) is a key enzyme in the process of pyrimidine and nucleoside metabolism. It is similar with platelet-derived endothelial cell growth factor(PD-ECGF) in structure and function. TP has angiogenesis activity, and correlates with tumor growth and metastasis. TP highly express in much tumor tissue, such as, gastric cancer,colorcetal cancer,ovarian cancer et al, compare with the normal tissue around tumor. But which kind cells express TP is not sure. And researchers did not get a same viewpoint about the prognosis role of TP. The prodrug , such as, 5'-deoxy-5-fluorouridine(5'-DFUR),capecitabine(CAP), et al, of 5-fluorouracil(5-FU) must be activated and transformed to 5-FU by TP. So we can enhance the anti-tumor effect of those prodrug through up-regulating the expressing of TP. We found in previous studies that TP expressed by macrophage-likes cell could enhance the effect of 5'-DFUR. Some papers reported cytokine could up-regulate TP, and we also found in previous studies that the accession of INF can make enhance the sensibility of colorectal cell to 5'-DFUR. We analysis TP expression and the relationship between TP and clinical feature,tumor prognosis through immunohistochemistry. We established the mouse models of colorectal cancer hepatic metastasis to study the effect of 5'-DFUR combined with interferon-α.Materials And MethodsExperiment one:53 specimens resected from patients with colorectal cancer which were from the Second Affiliated Hospital of Guanzhou Medical College. There were 50 specimens had complete follow-up date. These specimens were immunohistochemically stained by 654-1, anti-TP monoclonal antibody, 1C6-203, another anti-TP monoclonal antibody, PG-M1, anti-macrophage marker CD68 monoclonal antibody. Morphometrical analysis and positive cell counting were performed. Statistical analysis conducted with Spearman correlation analysis and Wilcocxon rank-sum test,one-way-ANOVA by using statistical software SPSS13.0. When P<0.05, that had a significant difference.Experiment TwoSPF-inbred BALB / c mouse 114, 6-8 weeks, male, body weight (20.23±2.13) g, purchased from the Sun Yat-sen University experimental Animal Center. The tumor cell line BALB/c mouse colon cancer cell line (CT26), buy from the American Type Culture Collection(ATCC). The experiment medicine 5'-deoxy-5-fluorouridine(5'-DFUR), from the Japanese company Roche Research Center; 5-fluorouracil(5-FU) injection, the Jiangsu Nantong drugs manufacture Limited company (the batch number: 060507); interferonα-2a, purchased from the Shanghai Roche Pharmaceutical Co.Ltd. Using spleen injection method establish model. Divided them randomly into 6 groups. And gave 6 groups Sodium Chloride,5-FU,5'-DFUR,peginterferon-α,5-FU+peginterferon-αand 5'-DFUR+peginterferon-αrespectively. Recoding the weight of the mouse at the first,the second and the third week after establish the models. Killing six mouse at the tenth and fiftieth day in every groups. And get the data, such as the weight of liver and spleen,ASL,ALT,UREA,CREA and count the number of nodus on the surface of liver. Statistical analysis conducted with one-way-ANOVA and chi-square criterion by using statistical software SPSS13.0. When P<0.05, that had a significant difference.ResultsExperiment oneThere were 27 patients alive to October 2007. We found TP positive cells most are macrophage around the cancer nest. Only in 5 specimens we found cancer cells 654-1 and(or) 1C6-203 antibody positive. And the distribution range of CD-68 antibody positive marked macrophages was almost the same with TP positive cells. And in polypus tissue we find the distribution of TP positive cells and CD-68 positive cells were not the same. The different antibody 654-1 and 1C6-203 marked positive cells were correlated, in tumor(r=0.661,P<0.001), and in polypus tissue(r=0.577,P<0.05). In tumor , the counting of 654-1(r = 0.647, P<0.001) positive cells and 1C6-203(r = 0.633,P<0.001) positive cells correlated with CD-68 positive cells. We did not find the same result in polypus. 654-1 positive cells did not correlate with location of tumor,patho-staging,differentiation,histology type. And the life span of patients did not correlate with 654-1 positive cells counting(r=0.540, P>0.05).Experiment TwoThe weight change of 5-FU group(-1.62±0.62g) and 5-FU combined with peginterferon-αgroup(-1.23±0.78g) were different with other groups(P<0.05). The weight of spleen in 5-FU and 5-FU combined with peginterferon-αgroup were different with sodium chloride group,peginterferon-αgroup and 5'-DFUR combined with peginterferon-αgroup at the tenth day(P<0.05). CREA value in 5'-DFUR group(23.8±11.9 umol/L) were different with 5'-DFUR combined with peginterferon-αgroup(38.7±19.1 umol/L) after 10 days since doing operation(P<0.05). AST value in 5-FU group(161.3±21.9 U/L) were different with sodium chloride group(354.5±292.9 U/L) after 15 days since doing operation(P<0.05). At the tenth day, the counting of tumor nodus in 5-FU group were less than the counting in peginterferon-αgroup and 5'-DFUR combined with peginterferon-αgroup(P<0.05). The counting of tumor nodus in 5-FU combined with peginterferon-αgroup were less than the counting in 5'-DFUR combined with peginterferon-αgroup(P<0.05). The life span of each group were not different in statistical analysis.ConclusionThe TP in colorectal cancer mainly expressed by TAM. The counting of TP positive cells in colorectal cancer did not correlated with life span. 5'-DFUR combined with peginterferon-αcould not enhance the anti-tumor effect to mouse.