Synthesis, in vitro and in vivo activity of thiamine antagonist transketolase inhibitors

Tumor cells extensively utilize the pentose phosphate pathway for the synthesis of ribose. Transketolase is a key enzyme in this pathway and has been suggested as a target for inhibition in the treatment of cancer. In a pharmacodynamic study, nude mice with xenografted HCT-116 tumors were dosed with 1 (‘N3′-pyridyl thiamine’; 3-(6-methyl-2-amino-pyridin-3-ylmethyl)-5-(2-hydroxy-ethyl)-4-methyl-thiazol-3-ium chloride hydrochloride), an analog of thiamine, the co-factor of transketolase. Transketolase activity was almost completely suppressed in blood, spleen, and tumor cells, but there was little effect on the activity of the other thiamine-utilizing enzymes α-ketoglutarate dehydrogenase or glucose-6-phosphate dehydrogenase. Synthesis and SAR of transketolase inhibitors is described.

Graphical abstractThe synthesis, SAR, and in vivo activity of highly potent thiamine mimetics utilized as transketolase (TK) antagonists is presented.Figure optionsDownload full-size imageDownload as PowerPoint slide