[Application of interleukin 1 in the treatment of malignant gliomas with special reference to the experimental combination therapy with ACNU].

The therapeutic potential of interleukin 1 (IL-1) in the treatment of malignant glioma was investigated. The direct effect of recombinant human IL-1 beta (rHuIL-1 beta) on cultured U-373 MG glioma cell was evaluated in vitro by BrdU uptake assay, and these effects were compared with those of human interferon beta (HuIFN-beta). Though a growth inhibition and an increase of the percentage of process bearing cells were observed with rHuIL-1 beta at a concentration of 100 ng/ml, these in vitro effects of rHuIL-1 beta were less than those of HuIFN-beta at the same concentrations. Prevention of and enhanced recovery from myelosuppression caused by ACNU by rHuIL-1 beta were evaluated in BALB/c mice. Intravenous injection of ACNU at a dose of 60 mg/kg caused marked decreases in the number of leukocytes, neutrophils, reticulocytes and thrombocytes after seven days. Pretreatment with 1 microgram/mouse of rHuIL-1 beta as a single i.p. injection had a significant preventive effect on these myelosuppression including thrombocytopenia. Enhanced recovery by rHuIL-1 beta administrated seven days after injection of ACNU was also observed. Experimental combination immunochemotherapy with ACNU and rHuIL-1 beta was performed in nude mice inoculated with human glioblastoma subcutaneously. More than 60 mg/kg of ACNU given intraperitoneally inhibited the growth of human glioblastoma in nude mice, but had no effect on survival time of nude mice. The antitumor effect of ACNU was significantly augmented by coadministration of 1 microgram/mouse rHuIL-1 beta. The elongation of the survival time of the tumor bearing nude mice was also observed in combined use of ACNU with rHuIL-1 beta. These results suggest that the combined use of IL-1 with chemotherapeutic agents seems to be desirable for clinical application in the treatment of patient with malignant gliomas from the viewpoints of the direct anti-tumor effect, the enhancement of the host immunity, and the prevention of myelosuppression caused by those agents.