Heat Shock Factor 1 Inhibitor, KRIBB11

A cell-permeable 2,6-diaminopyridine compound that interacts with HSF1 (heat shock factor 1) in a reversible manner and prevents HSF1 from recruiting p-TEFb (positive transcription elongation factor b) to the hsp70 promoter site (IC₅₀ ≤3 µM in HCT-116 ChIP assays), a critical step for the p-TEFb CDK9 subunit-catalyzed pol II CTD (RNA polymerase II c-terminal domain) Ser-2 phosphorylation and transcription activation upon heat shock induction (IC₅₀<1, <3, <5, and <10 µM, respectively, against reporter, HSP47, HSP27, and HSP70 transcription in HCT-116 cultures). Reported to exhibit antiproliferation activity against several cancer cultures in vitro (IC₅₀ ranges from 3 to 8 µM) and effectively suppress HCT-116-derived tumor growth in mice in vivo (by 47.4% on day 31; single i.p. dosage of 50 mg/kg on day 13 after cancer implantation). Does not affect TNF-α-induced NF-κB activity in HeLa or heat shock-induced HSF1 ser230 phosphorylation and promoter association in HCT-116 even at concentrations as high as 10 µM.

Packaged under inert gas

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.

Yoon, Y.J., et al. 2010. J. Biol. Chem.286, 1737.

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Toxicity: Standard Handling (A)