Retroviral Vector-mediated Expression of Human Thyimidine Phosphorylase in Pancreatic Carcinoma Cells

The level of human thymidine phosphorylase (TP) activity increased in several types of malignant tumors, but little was known about its physiological functions. A recombinant retroviral vector expressing TP was constructed and transferred into pancreatic carcinoma cells PC-2. The integration and expression of exogenous TP gene in the transduced cells was verified by PCR, Southern and Northern blotting, and in situ hybridization. The level of TP activity in TP-positive cells was 40- to 70-fold higher than that of parental PC-2 cells. However, there was no significant difference in cell growth and in (3)H-TdR incorporation rate between the transduced and parental cells. These results indicate that TP-expressing cell line has been successfully established, offering an excellent model system for studying the role of TP in cancer cell proliferation and seeking its specific substrates.