Promotion of metastases by tumor necrosis factor in rats bearing Dunning R3327 MAT-LyLu prostatic cancer.

We examined the effects of recombinant human tumor necrosis factor (rTNF) on highly metastatic rat prostatic cancer, Dunning R3327 MAT-LyLu, in vivo. It seemed that the inhibition of tumor growth needed more than 5 x 10(5) units of rTNF and this dose was near the lethal dose. Concerning the effect of rTNF on metastasis, we found that the metastasis to lung was promoted by 1 x 10(5) units of rTNF and the promotion of metastasis was restricted by indomethacin. Although MAT-LyLu cells were producing a significant amount of prostaglandin E2, rTNF did not enhance the production. We therefore consider that the promotion of metastasis was not mediated by prostaglandin E2 from MAT-LyLu cells but was mediated by other very complicated conditions. Further studies are necessary to resolve the mechanisms.