Ochromycinone ((Rac)-STA-21) is a natural antibiotic and a STAT3 inhibitor. Ochromycinone can inhibits STAT3 DNA binding activity, STAT3 dimerization. Ochromycinone has anticancer and antimicrobial activity[1][2].
STA-21 inhibits STAT3 DNA binding activity, STAT3 dimerization, and STAT3-dependent luciferase activity. Moreover, STA-21 reduces the survival of breast carcinoma cells with constitutive STAT3 signaling but has minimal effect on the cells in which constitutive STAT3 signaling is absent[2].
[1]. Song H, et al. A low-molecular-weight compound discovered through virtual database screening inhibits Stat3 function in breast cancer cells. Proc Natl Acad Sci U S A. 2005 Mar 29;102(13):4700-5. [2]. Nataliya I. Kalinovskaya, et al. New Angucyclinones from the Marine Mollusk Associated Actinomycete Saccharothrix espanaensis An 113. Natural product communications. 2008, 3(10):1611-1616.