Galiellalactone is a fungal metabolite isolated from the ascomycetes G. rufa strain A75-86 and A111-95 that inhibits IL-6-mediated JAK/STAT signal transduction in HepG2 cells with an IC50 value of 0.25-0.5 μM. The selectivity of this compound is achieved by its ability to block the binding of activated STAT3 dimers to their DNA binding sites without affecting phosphorylation of the STAT3 transcription factor. At 10-50 μM, galiellalactone exhibits dose-dependent growth inhibitory effects on prostate cancer stem cell-like cells expressing active STAT3, suggesting it may be a useful therapeutic approach to control JAK/STAT signaling.
Galiellalactone is a STAT3 inhibitor; active in vivo. Galiellalactone is also a promising compound for the development of future prostate cancer drugs.
Galiellalactone was originally isolated from Galiella rufa as a plant growth regulator. Recently it was shown to inhibit IL-6 induced SEAP expression with IC50 values of 250-500 nM, blocking the binding of the activated Stat3 dimers to their DNA binding sites without inhibiting the tyrosine and serine phosphorylation of the Stat3 transcription factor.
