ENHANCEMENT OF 5‐FLUOROURACIL CYTOTOXICITY BY CISPLATIN IN BRAIN TUMOUR CELL LINES

Cisplatin reportedly plays an important role as a chemical modulator in enhancing the chemotherapeutic effects of 5-fluorouracil on tumour cells. The aim of the present study was to test the synergistic cytotoxicity of cisplatin and 5-fluorouracil in 5-fluorouracil-resistant (C6) and -sensitive (9L) rat brain tumour cell lines. Survival fractions, determined using colony-formation assays, were compared following 5-fluorouracil treatment, with and without cisplatin. The presence of cisplatin (1-10 microM) enhanced cytotoxicity by more than three times compared with 5-fluorouracil alone in 5-fluorouracil-resistant C6 cells, whereas no enhancement effects were noted in 9L cells. These results suggest that a cisplatin-fluorouracil-based regimen may be promising in the treatment of 5-fluorouracil-resistant brain tumours.