In vitro and in vivo studies on potentiation of cytotoxic effects of anticancer drugs or cobalt 60 gamma ray by interferon on human neoplastic cells.

A possibility that interferon may potentiate the cytotoxic effects of anticancer drugs or 60Co gamma ray on human neoplastic cells was studied by in vitro and in vivo experimental procedures. The human neoplastic cells used were HeLa (uterine cervical cancer) and WI-38 CT-1 (embryonic lung fibroblasts transformed in culture by 60Co gamma ray) cells. As normal human cells, WI-38 cells were used. Interferon was a preparation of beta-type produced by human fibroblasts. The cytotoxicity was determined by colony formation for in vitro experiments and by tumor growth for animal experiments. Of 17 anticancer drugs, the cytotoxic effects of six drugs, namely, peplomycin, bleomycin, aclacinomycin, cisplatin, 5-fluorouracil (5-FU), and Adriamycin (doxorubicin) were potentiated by concomitant application of interferon. The cytolethal effects of 60Co gamma ray were also enhanced by interferon. The growth of tumor induced by transplantation of HeLa cells into a nude mouse was remarkably reduced by combination therapy of interferon and 5-FU. The current results indicate a possibility that combined therapy of certain types of anticancer drugs or 60Co gamma ray with interferon may be effective in treatment of cancer patients.