Synergistic potentiating effect of D(+)-mannose, orotic, and hippuric acidsodium salt on selective toxicity of a mixture of 13 substances of the circulatory system in culture for various tumor cell lines

Despite global immune system abnormalities in the autoimmune deficiency syn drome, the incidence of only a few tumor types increases, and the degree of immunosuppression does not seem to be critical in the development of these tumors, indicating that the immune system does not prevent tumor developme nt. Consequently, because tumors do not develop in most individuals, other defense systems may exist. We demonstrated previously that 13 substances in the circulatory system acting synergistically induced apoptosis in vitro a nd in vivo in different tumor cell lines, but not in normal cells and anima ls. We investigated another 17 compounds and five ions in the circulatory s ystem to determine their participation in the defense provided by the 13 su bstances. Three of the 17 substances but no ions had a potentiating effect on the mixture of substances used previously. The new 16-component mixture suppressed in vitro growth of six human and murine tumor cell lines, includ ing multidrug-resistant tumor cells, without cytotoxic effects in two norma l cell Lines. The selectivity also was demonstrated by investigating the mi xture's effect over time on tumor and normal cell growth.