Background: In vitro, in vivo and clinical studies have demonstrated anti-cancer effects of deuterium depletedwater (DDW). The nature of this agents action, cytotoxic or cytostatic, remains to be elucidated. We here aimedto address the point by examining effects on different cell lines. Materials and Methods: 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) -based cytotoxicity analysis was conducted for human breast,stomach, colon, prostate cancer and glioblastoma multiforme cell lines as well as human dermal fibroblasts. Thecell lines were treated with decreasing deuterium concentrations of DDW alone, paclitaxel alone and both. Oneway analysis of variance (ANOVA) was used for statistical analysis. Results: Treatment with different deuteriumconcentrations of DDW alone did not impose any significant inhibitory effects on growth of cell lines. Paclitaxelsignificantly decreased the survival fractions of all cell lines. DDW augmented paclitaxel inhibitory effects onbreast, prostate, stomach cancer and glioblastoma cell lines, with influence being more pronounced in breastand prostate cases. Conclusions: DDW per se does not appear to have inhibitory effects on the assessed tumorcell lines as well as normal fibroblasts. As an adjuvant, however, DDW augmented inhibitory effects of paclitaxeland thus it could be considered as an adjuvant to conventional anticancer agents in future trials.
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