Effect of pentazocine on Ehrlich ascites tumor cells

The effect of pentazocine, a non-narcotic analgesic, on Ehrlich ascites tumor cells was examined in vitro and in vivo. To test the in vitro effect of pentazocine, Ehrlich tumor cells suspended in Hanks balanced salt solution (BSS, pH 7.4) supplemented with 2% bovine albumin were incubated with various concentrations of the drug (0.10-1.0 mM) at 37 degrees C for 120 min. After incubation, the tumor cells in BSS were inoculated subcutaneously into the right flank of mice (10(6) cells/mouse). All mice given the tumor cells incubated alone developed solid tumor. However, no tumor growth was observed in groups of mice given the tumor cells pretreated with 0.3 or 1.0 mM pentazocine. The in vivo effect of pentazocine was then examined against Ehrlich ascites carcinoma in mice. Mice inoculated intraperitoneally with Ehrlich tumor cells in BSS (2 x 10(6) cells/mouse) were given various doses of pentazocine (20-80 mg/kg/day) intraperitoneally once a day for 5 successive days. The average survival time in a group of mice given the tumor cells alone was about 19 days, and the survival time was about 29 days in a group of animals treated with pentazocine in a dose of 80 mg/kg/day (p less than 0.01).