Oxythiamine (chloride hydrochloride)

Oxythiamine is a thiamine antimetabolite that has anticancer activities.{55009,55010,48952} It is converted by thiamine pyrophosphokinase to oxythiamine pyrophosphate, a transketolase inhibitor.{55009} Oxythiamine (5 mM) decreases transketolase activity in and is cytotoxic to MDA-MB-231 breast cancer cells.{48955} It inhibits the nonoxidative synthesis of ribose and decreases RNA and DNA synthesis in MIA PaCa-2 pancreatic cancer cells when used at a concentration of 0.5 µM.{55010} In vivo, oxythiamine (400 and 500 mg/kg per day) induces cell cycle arrest at the G1 phase and apoptosis in an Ehrlich murine spontaneous adenocarcinoma model.{48952} Oxythiamine, in combination with sorafenib, reduces tumor growth in an SMMC mouse xenograft model.{48953} It has also been used to induce thiamine deficiency in mice.{48954}