In-vitro effect of a combination of 5-fluorouracil (5-FU) and cisplatin (CDDP) on human gastric cancer cell lines: timing of cisplatin treatment.

BACKGROUND: To date, we have few effective chemotherapeutic agents against advanced and recurrent gastric cancer. 5-Fluorouracil (5-FU) and cisplatin (CDDP) are the most widely used drugs, and their combination has demonstrated favorable outcomes. However, the method (especially the timing) of CDDP administration is not well established.
METHODS: We examined the in-vitro effect of a combination of 5-FU and CDDP on four human gastric cancer cell lines: MKN-1, MKN-28, MKN-45, and MKN-74. The cell lines were exposed to 50% of the inhibitory concentrations of 5-FU and CDDP for 72 h and 8 h, respectively. CDDP was applied before, simultaneously with, and after the start of treatment with 5-FU.
RESULTS: When CDDP was applied after 5-FU, the cytotoxic activity against MKN-28, MKN-45, and MKN-74 was significantly potentiated. Against MKN-1, the earlier the initiation of CDDP treatment, the stronger was the cytotoxic effect.
CONCLUSION: Our results suggest that the cytotoxicity of a combination of 5-FU and CDDP against human gastric cancer cells is both cell-line- and schedule-dependent and is especially affected by the timing of the CDDP treatment.