Growth-inhibition of leukemia L-1210 ascites tumor by combination of carrageenan and mitomycin C in vivo.

A purified i-carrageenan prepared by means of pronase digestion and fractional precipitation with KCl was investigated for its growth-inhibitory effect on mouse leukemia L-1210 transplanted in (C57BL/6 x DBA/2)F1 (BDF1) mice. This carrageenan specimen was not growth-inhibitory on this tumor when it was administered alone in a dose of 0.1 to 10 mg/kg/d, 4 times. However, in combination, with a small amount of mitomycin C, 0.25 mg/kg/d, a remarkable tumor growth-inhibition has manifested affording a complete regression of this tumor. Acid phosphatase alpha-galactosidase and active oxygen generation activities of the peritoneal exudate cells in the carrageenan-administered mice were remarkably higher than those of the control mice. Therefore, the booster effect of this carrageenan preparation on antitumor activity of mitomycin C is assumed to be associated with the inflammatory activity of this sulfated polysaccharide.