TPh A (Triphenyl Compound A) is a potent inhibitor of the nuclear protein pirin and binds specifically to pirin with a Ki of 0.6 uM. TPh A disrupts the formation of the bcl3-pirin complex. TPh A can be used as a novel small molecule tool to regulate pirin in cells[1].

The Pirin is a nuclear protein with the nuclear factor I/CCAAT box transcription factor (NFI/CTF). Pirin proteins are highly conserved between mammals, plants, fungi, and prokaryotic organisms and are considered to belong to the cupin superfamily.TPh A (20 µM; 5 hours) reduces the amount of pirin-bound Bcl3 and inhibits the interaction between pirin and Bcl3 in HEK293T cells in a glutathione S-transferase (GST) pulldown assay (HEK293T cells are transfected with vectors that encoded bcl3-Myc and pirin-His6 for 43 h of transfection)[1].TPh A (0-100 µM; 48 hours) does not exert any potent cytotoxic activity against many human cancer cell lines, it against MCF7, MDA-MB231, HeLa, DU145, HepG2, A549, HT1080, WM266-4, and SK-MEL-28 cells with IC50 values >50 µM, and exhibits IC50 values of 27 µM, 20 µM and 26 µM for PC3 HL60 and HT29 cells, respectively[1].TPhA (0-50 µM; 48 hours) inhibits cell migration in WM266-4 cells, SK-MEL-28 cell in a concentration-dependent manner[1].

References:
[1]. Isao Miyazaki, et al. A Small-Molecule Inhibitor Shows That Pirin Regulates Migration of Melanoma Cells. Nat Chem Biol. 2010 Sep;6(9):667-73.