Synergistic activation of macrophage activity by polyamine deprivation and cyclophosphamide.

A synergistic reduction in tumor growth rate and of metastasis dissemination together with an increased life span, were observed when polyamine deprivation was combined with a low dose of cyclophosphamide. When rats were treated with this combination treatment, TNF and NO release was enhanced and phagocytic activity was increased. In addition, PGE2 release by macrophages was enhanced, whereas PGE2 plasma levels were restored to normal values. The decrease in PGE2 plasma levels presumably indicates the synergistic effect of the combination treatment on tumor cell metabolism. The enhancement of macrophage tumoricidal activities indicates immunostimulating synergistic effects, which may contribute to the anti-tumoral effect of the treatment.