The mammalian transcription factor forkhead box M1 (FoxM1) is induced during G1 phase, with expression continuing through S phase and mitosis. Thiostrepton is a natural peptide thiazole antibiotic that inhibits FoxM1 in mammalian cells, preventing the expression of FoxM1-regulated genes, which includes FoxM1 itself. Through this mechanism, thiostrepton prevents proliferation and induces apoptosis in human cancer cells. These effects correlate with the ability of thiostrepton to act as a proteasome inhibitor.
