Siomycin A is a thiopeptide antibiotic and is a Forkhead box M1(FOXM1) selective inhibitor without affecting other members of the Forkhead box family. Siomycin A has anti-tumor and promotes apoptosis^[1][2]. IC50 & Target: Forkhead box M1(FOXM1)^[1] In Vitro: Siomycin A (0-10 µM; 24-72 hours; K562, MCF7 and MiaPaCa-2 cells) treatment markedly reduces cell viability in a dose-dependent and a time-dependent association in K562, MCF7 and MiaPaCa-2 cells. Among the three cell lines, the IC₅₀ of the human leukemia K562 cells is the lowest at 6.25 µM at 24 h, while that for the human pancreatic cancer MiaPaCa-2 cells is 6.38 µM. However, the IC₅₀ of the human pancreatic cancer MiaPaCa-2 cells at 48 and 72 h are the lowest of the three cell lines, which are 0.76 and 0.54 µM, respectively^[1].
Siomycin A (0-10 µM; MiaPaCa-2 cells) treatment has potent proapoptotic effect in MiaPaCa-2 cells^[1].
Siomycin A (0-10 µM; 24 hours; MiaPaCa-2 cells) treatment significantly reduces the expression levels of MMP-2, MMP-9 and α-tubulin protein in the MiaPaCa-2 cells^[1]. In Vivo: Siomycin A (1 µM; subcutaneous injection; for 4 weeks; male Balb/c nude mice) pretreatment decreases tumour growth in an in vivo mouse model^[2].