[Antitumor effect of interferons with chemotherapeutic agents]

The combined effect of human interferons and chemotherapeutic agents on human gastric cancer cell lines and a human pancreatic cancer cell line was studied in vitro. Interferons, when used as a single drug, showed inhibitory effects in the order, gamma greater than beta greater than alpha. However, there was no significant difference between the effects of natural and recombinant interferon. In combination therapy, the chemotherapeutic agents should be administered first, followed by administration of interferon(s), since this method showed the most inhibitory effect. Low concentration of 5-FU (0.001-0.01 microgram/ml) or methotrexate (0.01-1 microgram/ml) was able to inhibit the growth of cell lines when combined with interferon. These results suggested that in clinical use, low amounts of chemotherapeutic agents followed by administration of interferon(s) could be available with minimum side effects and with more pronounced anticancer effects.