Pyrimidine Nucleoside Phosphorylase in Brain Tumors and Antitumor Effect of 5’-DFUR

Abstract

The antitumor effect of 5’-deoxy-5-fluorouridine (5-DFUR) against experimental glioma cells was investigated in vitro and in vivo. 5-DFUR is a newly synthesized masked compound of 5-FU, which is activated only in the presence of pyrimidine nucleoside phosphorylase. This enzyme has been reported to exist much more in malignant tumors, such as Sarcoma 180 and Ehrlich ascites carcinoma, than in normal tissues. The activities analysed in 9L, RG12, and 203GL cells were 24.3, 75.1, and 8.1% respectively of the activity in Sarcoma 180. Normal rat brain showed 22.8% of the activity. Growth curves of cultured 9L and RG12 cells showed a dose-dependent 5’-DFUR antitumor effect when it was used at a concentration of over 10 (μg/ml. The colony forming rate of 9L cells treated with 20 fig/ml of 5-DFUR decreased to 10%. The inhibition rate of 203GL cells transplanted subcutaneously into C57BL mice was 52.3% in weight, and that of human glioblastoma cells transplanted subcutaneously into nude mice was 20.9% in size after treatment with 5-DFUR, 400 mg/kg/day for ten consecutive days. When 9L cells were transplanted intracranially into CD Fisher rats, their median survival time became four days longer than that of non-treated rats. Flowcytometric analysis of in vitro 9L cells and in vivo 203GL cells showed an accumulation in the cells between the 2C and 4C components after treatment of 5-DFUR. It seems that a delay in DNA synthesis occurred in the presence of this drug. This newly synthesized antitumor drug is expected to be effective for the treatment of malignant brain tumors. © 1984, The Japan Neurosurgical Society. All rights reserved.