The antitumor effect of intraperitoneal treatment with rhTNF-α muteins on Ehrlich ascites tumor growth

The intraperitoneal (i.p.) treatment with recombinant human tumor necrosis factor-alpha (rhTNF-alpha) is one of the possible therapies for tumors that are confined to the abdominal cavity. Clinical trials aiming at the exploitation of the antitumor effects of rhTNF-alpha have been largely disappointing. In this model the activity of some rhTNF-alpha derivatives was studied. Ehrlich's ascites tumor (EAT) bearing Swiss albino male mice were treated i.p. three times a week with 10 micrograms/mice of rhTNF-alpha, mutein V or mutein VI for two weeks, starting on the 4th day after tumor inoculation. Control mice received PBS. The effect of the rhTNF-alpha derivatives on the course of EAT was evaluated basing on: total ascites volume (TAV); packed cell volume (PCV); total packed cell volume (TPCV); inhibitory growth rate (IGR); cellular population of EAT fluid; morphological EAT cell changes and mean survival time (MST). In the study mutein VI had only a slight effect on MST but significant on TAV- and TPCV-IGR (p < 0.001). In mice treated with rhTNF-alpha and mutein V the enhancement of MST (p < 0.01) was accompanied by TAV- and TPCV-IGR (p < 0.001). The number of EAT cells in ascites decreased after rhTNF-alpha and mutein V administration (p < 0.001). We conclude that treatment with high-dose of this modified molecule lacking the possibility of binding with p75R and not producing so intensified side effects is likely to find wider application in therapy and prevent the ascites growth just as rhTNF-alpha dosage.