SYNERGISTIC ANTITUMOR-ACTIVITY OF VITAMIN-C AND VITAMIN-K-3 AGAINST HUMAN PROSTATE CARCINOMA CELL-LINES

Vitamins C, K-3 (VC, VK3) and a VC/VK3 combination with a VC:VK3 ratio of 100:1 were assayed for their antitumour activity against two human prostatic carcinoma cell lines. Co-administration of the vitamins enh anced the antitumour activity 5- to 20-fold even with a 1 h exposure t ime. While exogenous catalase destroyed the antitumour activity, hydro gen peroxide-induced lipid peroxidation was negligible. Analysis of ce llular ATP and thiol levels as well as DNA and protein synthesis revea led: a transient increase in ATP production, a decrease in DNA synthes is, an increase in protein synthesis and a decrease in thiol levels. T hese results suggested that the increased cytotoxicity of the vitamin combination was due to redox cycling and increased oxidative stress. ( C) 1996 Academic Press Limited.