Catalog No. Size PriceQuantity
M12394-2 2mg solid $100
M12394-10 10mg solid $300


KRIBB11 is an inhibitor of Heat shock factor 1 (HSF1), with IC50 of 1.2 μM.

Product information

CAS Number: 342639-96-7

Molecular Weight: 284.27

Formula: C13H12N6O2

Chemical Name: N2-(1H-indazol-5-yl)-N6-methyl-3-nitropyridine-2, 6-diamine

Smiles: CNC1=CC=C(C(NC2C=C3C=NNC3=CC=2)=N1)[N+]([O-])=O


InChi: InChI=1S/C13H12N6O2/c1-14-12-5-4-11(19(20)21)13(17-12)16-9-2-3-10-8(6-9)7-15-18-10/h2-7H,1H3,(H,15,18)(H2,14,16,17)

Technical Data

Appearance: Solid Power

Purity: ≥98% (or refer to the Certificate of Analysis)

Solubility: DMSO : ≥ 27 mg/mL (94.98 mM)

Shipping Condition: Shipped under ambient temperature as non-hazardous chemical or refer to Certificate of Analysis

Storage Condition: Dry, dark and -20 oC for 1 year or refer to the Certificate of Analysis.

Shelf Life: ≥360 days if stored properly.

Stock Solution Storage: 0 - 4 oC for 1 month or refer to the Certificate of Analysis.

Drug Formulation: To be determined

HS Tariff Code: 382200

How to use

In Vitro:

KRIBB11 blocks the induction of HSF1 downstream target proteins such as HSP27 and HSP70. KRIBB11 induces growth arrest and apoptosis of HCT-116 cells. KRIBB11 inhibits HSF1-dependent recruitment of p-TEFb (positive transcription elongation factor b) to the hsp70 promoter. PARP and caspase-3 cleavage is increased in cells treated with KRIBB11. Incubating RKO with KRIBB11, shows a toxic threshold of about 10 µM, and an IC50 of 20-30 µM.

In Vivo:

KRIBB11 (50 mg/kg, i.p.) results in a 47.4% inhibition of tumor growth in nude mice, without body weight loss.


  1. Yoon YJ, et al. KRIBB11 inhibits HSP70 synthesis through inhibition of heat shock factor 1 function by impairing the recruitment of positive transcription elongation factor b to the hsp70 promoter. J Biol Chem. 2011 Jan 21;286(3):1737-47
  2. Samarasinghe B, et al. Heat shock factor 1 confers resistance to Hsp90 inhibitors through p62/SQSTM1 expression and promotion of autophagic flux. Biochem Pharmacol. 2014 Feb 1;87(3):445-55

Products are for research use only. Not for human use.

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