STAT5 Inhibitor is a cell-permeable inhibitor of STAT5 with IC50 value of 47 μM against STAT5β SH2 domain EPO peptide binding activity [1].

Signal Transducers and Activators of Transcriptions (STATs) are a family of transcription factors that are primarily activated by membrane receptor-associated Janus kinases (JAK) in response to a large number of extracellular signaling molecules including interferons, cytokines, and growth factors, and mediate many aspects of cellular immunity, proliferation, apoptosis and differentiation [2][3]. STAT5 consists of two isoforms STAT5α and STAT5β and is overactive in several kinds of cancers [1].

STAT5 Inhibitor is a cell-permeable STAT5 inhibitor. STAT5 Inhibitor inhibited STAT5β SH2 domain EPO peptide binding activity with IC50 value of 47 μM and exhibited less potency inhibiting the SH2 domain of STAT1, STAT3, and LCK by 36%, 26% and 7% at 500 μM, respectively [1]. In lysates from K562 cells, STAT5 Inhibitor reduced the concentration of STAT5/STAT5/DNA complex in a dose-dependent way [1].

References:
[1].  Müller J, Sperl B, Reindl W, et al. Discovery of chromone-based inhibitors of the transcription factor STAT5. Chembiochem. 2008 Mar 25;9(5):723-7.
[2].  Leonard WJ, O'Shea JJ. Jaks and STATs: biological implications. Annu Rev Immunol. 1998;16:293-322.
[3].  Schindler C, Darnell JE Jr. Transcriptional responses to polypeptide ligands: the JAK-STAT pathway. Annu Rev Biochem. 1995;64:621-51.