KRIBB11 is an inhibitor of the transcription factor He at Shock Factor 1 (HSF1) with an IC50 value of 1.2 μM. KRIBB11 blocks induction of HSF1 downstream target proteins such as HSP27 and HSP70 by impairing the recruitment of Positive Transcription Elongation Factor b (P-TEFb) to the HSF1 transcriptional complex, preventing HSF1-mediated gene expression KRIBB11 inhibits tumor growth in vivo and acts synergistically to increase apoptosis in cancer cells treated with the HSP90 inhibitors Geldanamycin and 17-AAG.', 'KRIBB11 is capable of preventing the proliferation of cancer cells. It has the ability to stimulate apoptosis and can arrest the cell cycle at G2/M phase.
