Selective toxicity of 1-naphthol to human colorectal tumour tissue.

1-Naphthol was selectively toxic to human colorectal tumours compared to corresponding normal colonic tissue removed at surgery and maintained in short-term organ culture. Nineteen of 24 tumours studied have shown a significant differential response. Three human colonic adenocarcinoma xenografts, in the short-term organ culture system, displayed the same response to 1-naphthol as primary tumours removed at surgery. 1-Naphthol, 1,2- and 1,4-naphthoquinone were also toxic to two human colonic adenocarcinoma cell lines, LoVo and COLO 206. The selective toxicity of 1-naphthol is mediated in part through an accumulation of 1-naphthol in the tumour tissue due to impaired conjugation by the tumour. The higher concentrations of 1-naphthol may then exert their toxicity either directly or by formation of naphthoquinones. Some indirect evidence was obtained for the possible involvement of 1,2- or 1,4-naphthoquinone in the cytotoxicity of 1-naphthol. Our studies suggest that further studies are warranted of the possible use of 1-naphthol or related compounds as antitumour agents.