EFFECT OF INTERLEUKIN-1-BETA ON METASTASIS FORMATION IN DIFFERENT TUMOR SYSTEMS

Experiments were done to determine the effect of interleukin-1-beta (IL-1-beta) on metastasis formation in different tumor systems. Intravenous administration of 1-mu-g of human recombinant IL-1-beta given 1 hour before tumor cell injection augmented lung colony formation (experimental metastases) by the human A375 melanoma variants, the human HT-29M colon carcinoma, the SN12-K1 renal carcinoma in nude mice, the murine B16 melanoma variants, and the murine UV-2237M fibrosarcoma in syngeneic recipients. The same treatment did not induce lung colony formation by a human rectal carcinoma (HCC-P2988) or by a murine reticulum cell sarcoma (M5076), both of which are not metastatic to the lung. Spontaneous metastases were studied in C57BL/6 mice bearing the B16-BL6 melanoma (metastatic to the liver) subcutaneously. Daily intraperitoneal treatment with 1-mu-g of IL-1-beta increased lung and liver metastases. These findings indicate that treatment of mice with IL-1-beta can increase the number of artificial or spontaneous metastases and that this effect is not limited to a single tumor type or to a specific organ.