1. Cell Cycle/DNA Damage Metabolic Enzyme/Protease Apoptosis
  2. HSP Apoptosis
  3. KRIBB11


Cat. No.: HY-100872 Purity: 99.54%
COA Handling Instructions

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

For research use only. We do not sell to patients.

KRIBB11 Chemical Structure

KRIBB11 Chemical Structure

CAS No. : 342639-96-7

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Solid + Solvent
10 mM * 1 mL in DMSO
ready for reconstitution
USD 66 In-stock
10 mM * 1 mL in DMSO USD 66 In-stock
5 mg USD 60 In-stock
10 mg USD 96 In-stock
25 mg USD 216 In-stock
50 mg USD 360 In-stock
100 mg USD 648 In-stock
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500 mg   Get quote  

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Customer Review

Based on 18 publication(s) in Google Scholar

Top Publications Citing Use of Products

    KRIBB11 purchased from MedChemExpress. Usage Cited in: Arch Biochem Biophys. 2023 Jan 23;109525.  [Abstract]

    KRIBB11 (0, 10, 20 µM; 24 h)completely blocks n-butyrate-mediated HSP70 expression and Hspa1α promoter activation in Caco-2 cells (fig B and C).

    KRIBB11 purchased from MedChemExpress. Usage Cited in: Cell Death Dis. 2017 Dec 12;8(12):3203.  [Abstract]

    Immunoblot showing that HSF1 inhibitor KRIBB11 and transcription inhibitor Act-D both fail to block RIP140 degradation.

    KRIBB11 purchased from MedChemExpress. Usage Cited in: Mol Oncol. 2017 Oct;11(10):1475-1492.  [Abstract]

    (A) IHC staining of N-cadherin and E-cadherin in the pancreas from KPC mice treated with vehicle, Metformin, or KRIBB11. (B) Masson's trichrome staining and IHC staining of α-SMA in pancreatic tissues from mice treated with vehicle, Metformin, or KRIBB11.

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    • Biological Activity

    • Protocol

    • Purity & Documentation

    • References

    • Customer Review


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

    IC50 & Target[1]


    1.2 μM (IC50)

    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[1]. 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[2].

    MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

    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].

    MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

    Molecular Weight




    CAS No.



    Yellow to orange




    Room temperature in continental US; may vary elsewhere.

    Powder -20°C 3 years
    4°C 2 years
    In solvent -80°C 2 years
    -20°C 1 year
    Solvent & Solubility
    In Vitro: 

    DMSO : 125 mg/mL (439.72 mM; Need ultrasonic)

    Stock Solutions
    Concentration Solvent Mass 1 mg 5 mg 10 mg
    1 mM 3.5178 mL 17.5889 mL 35.1778 mL
    5 mM 0.7036 mL 3.5178 mL 7.0356 mL
    10 mM 0.3518 mL 1.7589 mL 3.5178 mL
    *Please refer to the solubility information to select the appropriate solvent.
    Purity & Documentation

    Purity: 99.54%

    Kinase Assay

    HCT-116 cells are washed with PBS and then homogenized with a 27-gauge syringe in binding buffer (10 mm Tris-HCl (pH 7.4), 50 mm KCl, 5 mm MgCl2, 1 mm EDTA, and 0.1 mm Na3VO4). The cell lysate is centrifuged at 13,000 rpm for 30 min at 4°C, and the supernatant is collected. The HCT-116 cell lysate supernatant is precleared by incubating with Dynabeads M-280 streptavidin for 30 min at 4°C and captured by magnet separation. The cleared supernatants are incubated with biotinyl-KRIBB11 compound. After overnight incubation at 4°C, proteins associated with the biotinyl-KRIBB11 compound are precipitated with Dynabeads M-280 streptavidin. Precipitated samples are separated by a magnet. Samples are washed with 1 mL of ishing buffer containing 50 mm HEPES (pH 7.5), 50 mm NaCl, 1 mm EDTA, 1 mm EGTA, 0.1% Tween 20, 10% (v/v) glycerol, 1 mm NaF, 0.1 mm Na3VO4, and protease inhibitor mixture tablets (1 tablet/10 mL). Samples are boiled in SDS-PAGE sample buffer, separated by 10% polyacrylamide gel, and immunoblotted with antibodies against HSF1, HSF2, HSP90, or CDK9.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

    Cell Assay

    Cells are seeded onto 96-well plates at a density of 6×103 cells per well in McCoy's 5A medium with 10% FBS. After 24 h, the medium is replenwashed with fresh complete medium containing chemicals or 0.1% DMSO. After incubation for 48 h, the cell proliferation reagent WST-1 is added to each well. The amount of WST-1 formazan produced is measured at 450 nm using an ELISA reader.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

    Animal Administration

    Seven-week-old female inbred specific pathogen-free Balb/c nude mice are housed under sterile conditions with 12-h light/dark cycles, and fed food and water ad libitum. For the evaluation of the in vivo anti-tumor activity of KRIBB11, HCT-116 cells (0.3 mL of 4×107 cells/mL) are implanted subcutaneously into the right flank of the mice on day 0. KRIBB11 is dissolved in 10% dimethylacetamide, 50% PEG300, and 40% distilled water. When the size of tumors reached 72.2 mm3, the compound is administered intraperitoneally at a dose of 50 mg/kg/day for 18 days. Tumor volumes are estimated by using the formula length (mm) × width (mm) × height (mm)/2. To determine the toxicity of the compound, the body weight of tumor-bearing animals is recorded. On day 18, the mice are sacrificed, and the tumors are weighed.

    MCE has not independently confirmed the accuracy of these methods. They are for reference only.

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    • Do most proteins show cross-species activity?

      Species cross-reactivity must be investigated individually for each product. Many human cytokines will produce a nice response in mouse cell lines, and many mouse proteins will show activity on human cells. Other proteins may have a lower specific activity when used in the opposite species.

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