Interaction between Gambogic acid and dihydrofolate reductase and synergistic lethal effects with methotrexate on hepatoma cells.

Gambogic acid (GA), a natural xanthone, has a wide spectrum of pharmacological activities, including repression of telomerase expression and induction of apoptosis of cancer cells. GA has also been reported to reduce the steady-state level of thymidylate synthetase mRNA in a gastric carcinoma cell line. Therefore, it has recently emerged as a candidate for use in cancer treatment.