Non-toxic sensitization of cancer chemotherapy by combined vitamin C and K3 pretreatment in a mouse tumor resistant to oncovin.

The effects of combined vitamin C and K3 i.p. injected 3 hours before i.p. administration of single dose of oncovin, to which the ascites liver tumor in mouse (T.L.T.) was completely resistant, were investigated. This pretreatment sensitized the tumor resistant to oncovin, whereas a separate pretreatment with vitamin C or K3 alone was without any effect. This tumor sensitization to the chemotherapy was completely suppressed by catalase pretreatment, thus indicating that hydrogen peroxide generation with subsequent oxidative stress and its consequences may be involved here. Since this sensitization was without any increased general and organ toxicity, its possible introduction into classical protocols of human cancer treatment would be without any supplementary risk.