AIM:To detect the thymidine phosphorylase (dThdPase) expression in human colorectal cancer tissues and cells.METHODS:Forty specimens resected from patients with colorectal cancer were immunohistochemically stained by ...AIM:To detect the thymidine phosphorylase (dThdPase) expression in human colorectal cancer tissues and cells.METHODS:Forty specimens resected from patients with colorectal cancer were immunohistochemically stained by 654-1, anti-dThdPase monoclonal antibody, PG-M1,anti-macrophage marker CD68 monoclonal antibody.Morphometrical analysis and positive cell counting were performed. In 27 of 40 specimens, dThdPase activity was also assayed by HPLC. Otherwise, the dThdPase level was measured by ELISA in 6 colorectal cancer cell lines, LS174T,Clone A, Colo320, CX-1, Lovo, and MIP101, as well as in 2 macrophage-like cell lines, THP-1 and U937.RESULTS:dThdPase activity was significantly increased in cancer tissues compared with adjacent normal tissue (P<0.01).In immunohistochemical analysis, it was confirmed that most cells expressed dThdPase were the stromal cells surrounding cancer nests or along the invasive margin of cancer. Based on their morphometrical characteristics, we found that most of them were tumor-associated macrophages (TAMs). The number of dThdPase-positive stromal cells was significantly correlated with the number of CD68-positive macrophages (r=0.76, P<0.0001). By ELISA,18.2 unit/mg and 19.3 unit/mg of dThdPase protein were detected in THP-1 and U937,but only little was detected in 6 colorectal cancer cell lines.CONCLUSION:The present data suggest that dThdPase expression is seldom detected in colorectal carcinoma cells.TAM is the most important source of dThdPase in colorectal cancer tissues.展开更多
Nucleoside phosphorylases (NPases) were found to be induced in Enterobacter aerogenes DGO-04, and cytidine and cytidine 5′-monophosphate (CMP) were the best inducers. Five mmol/L to fifteen mmol/L cytidine or CMP cou...Nucleoside phosphorylases (NPases) were found to be induced in Enterobacter aerogenes DGO-04, and cytidine and cytidine 5′-monophosphate (CMP) were the best inducers. Five mmol/L to fifteen mmol/L cytidine or CMP could distinctly increase the activities of purine nucleoside phosphorylase (PNPase), uridine phosphorylase (UPase) and thymidine phosphorylase (TPase) when they were added into medium from 0 to 8 h. In the process of enzymatic synthesis of adenine arabinoside from adenine and uracil arabinoside with wet cells of Enterobacter aerogenes DGO-04 induced by cytidine or CMP, the reaction time could be shortened from 36 to 6 h. After enzymatic reaction the activity of NPase in the cells induced remained higher than that in the cells uninduced.展开更多
Objectives.To observe if lysophosphatidic acid(LPA)can influence nuclear nucleoside triphos-phatase(NTPase)activity of isolated hepatocyte from rat,and to investigate the possible mechanisms by which LPA affects the N...Objectives.To observe if lysophosphatidic acid(LPA)can influence nuclear nucleoside triphos-phatase(NTPase)activity of isolated hepatocyte from rat,and to investigate the possible mechanisms by which LPA affects the NTPase.Method.Isolated and cultured hepatocytes from rat liver were exposed to LPA(1×10 -9 ,1×10 -8 and5×10 -8 mol/L)with or without inhibitors of protein kinase C(PKC)and mitogen activating protein kinase kinase(MAPKK),and the NTPase activity on nuclear envelope was assayed using ATP and GTP as substrate,respectively.Results.Nuclear NTPase activity of rat hepatocytes was potently stimulated by incubation of hepato-cytes with LPA in concentration?and time ?dependent manners.In hepatocytes incubated with LPA,nu-clear NTPase activity was significantly higher than that of the control(P<0.01).In hepatocytes preincu-bated with PKC inhibitor H-7or MAPKK inhibitor PD98059,LPA-stimulated activation of nuclear NT-Pase was obviously attenuated.In addition,direct incubation of isolated hepatic nuclei with LPA had no effect on nuclear NTPase activity.Conclusion.LPA is involved in modulating nuclear NTPase activity in hepatocytes.The stimulating effect of LPA on the nuclear NTPase is mediated at least partly by PKC and MAPK-dependent pathway.展开更多
基金Supported by Grants-in-Aid for Scientific Research from the Ministry of Education,Culture,Sports and Technology,Japan
文摘AIM:To detect the thymidine phosphorylase (dThdPase) expression in human colorectal cancer tissues and cells.METHODS:Forty specimens resected from patients with colorectal cancer were immunohistochemically stained by 654-1, anti-dThdPase monoclonal antibody, PG-M1,anti-macrophage marker CD68 monoclonal antibody.Morphometrical analysis and positive cell counting were performed. In 27 of 40 specimens, dThdPase activity was also assayed by HPLC. Otherwise, the dThdPase level was measured by ELISA in 6 colorectal cancer cell lines, LS174T,Clone A, Colo320, CX-1, Lovo, and MIP101, as well as in 2 macrophage-like cell lines, THP-1 and U937.RESULTS:dThdPase activity was significantly increased in cancer tissues compared with adjacent normal tissue (P<0.01).In immunohistochemical analysis, it was confirmed that most cells expressed dThdPase were the stromal cells surrounding cancer nests or along the invasive margin of cancer. Based on their morphometrical characteristics, we found that most of them were tumor-associated macrophages (TAMs). The number of dThdPase-positive stromal cells was significantly correlated with the number of CD68-positive macrophages (r=0.76, P<0.0001). By ELISA,18.2 unit/mg and 19.3 unit/mg of dThdPase protein were detected in THP-1 and U937,but only little was detected in 6 colorectal cancer cell lines.CONCLUSION:The present data suggest that dThdPase expression is seldom detected in colorectal carcinoma cells.TAM is the most important source of dThdPase in colorectal cancer tissues.
基金Project (No. 07C26213101283) supported by the Innovation Fundfor Technology Based Firms from the Ministry of Science andTechnology of China
文摘Nucleoside phosphorylases (NPases) were found to be induced in Enterobacter aerogenes DGO-04, and cytidine and cytidine 5′-monophosphate (CMP) were the best inducers. Five mmol/L to fifteen mmol/L cytidine or CMP could distinctly increase the activities of purine nucleoside phosphorylase (PNPase), uridine phosphorylase (UPase) and thymidine phosphorylase (TPase) when they were added into medium from 0 to 8 h. In the process of enzymatic synthesis of adenine arabinoside from adenine and uracil arabinoside with wet cells of Enterobacter aerogenes DGO-04 induced by cytidine or CMP, the reaction time could be shortened from 36 to 6 h. After enzymatic reaction the activity of NPase in the cells induced remained higher than that in the cells uninduced.
文摘Objectives.To observe if lysophosphatidic acid(LPA)can influence nuclear nucleoside triphos-phatase(NTPase)activity of isolated hepatocyte from rat,and to investigate the possible mechanisms by which LPA affects the NTPase.Method.Isolated and cultured hepatocytes from rat liver were exposed to LPA(1×10 -9 ,1×10 -8 and5×10 -8 mol/L)with or without inhibitors of protein kinase C(PKC)and mitogen activating protein kinase kinase(MAPKK),and the NTPase activity on nuclear envelope was assayed using ATP and GTP as substrate,respectively.Results.Nuclear NTPase activity of rat hepatocytes was potently stimulated by incubation of hepato-cytes with LPA in concentration?and time ?dependent manners.In hepatocytes incubated with LPA,nu-clear NTPase activity was significantly higher than that of the control(P<0.01).In hepatocytes preincu-bated with PKC inhibitor H-7or MAPKK inhibitor PD98059,LPA-stimulated activation of nuclear NT-Pase was obviously attenuated.In addition,direct incubation of isolated hepatic nuclei with LPA had no effect on nuclear NTPase activity.Conclusion.LPA is involved in modulating nuclear NTPase activity in hepatocytes.The stimulating effect of LPA on the nuclear NTPase is mediated at least partly by PKC and MAPK-dependent pathway.
