| Field | Specification |
|---|---|
| Target | |
| CAS no. | |
| Applications | |
| Molecular weight | |
| Molecular formula | C18H17NO4 |
| Purity | |
| SMILES | |
| Form | Solid |
| Storage | |
| Shipping | |
| Catalog no. (Mfr.) | |
| Main SKU |
Compound Overview
IC261 is a selective, ATP-competitive inhibitor of CK1, with IC50 values of 1 μM, 1 μM, and 16 μM against Ckiδ, Ckiε, and Ckiα1, respectively. It is supplied as a light yellow to yellow solid (C18H17NO4, MW 311.33) at 99.63% purity.
Physical & Chemical Properties
| CAS Number | 186611-52-9 |
|---|---|
| Molecular Formula | C18H17NO4 |
| Molecular Weight | 311.33 g/mol |
| Purity | 99.63% |
| Appearance | Solid |
| Color | Light yellow to yellow |
| SMILES | O=C1NC2=C(C=CC=C2)/C1=C\C3=C(OC)C=C(OC)C=C3OC |
| Target | CK1δ, CK1α1 |
| Signaling Pathway | Cell Cycle/DNA Damage; Stem Cell/Wnt; Apoptosis |
| Solubility | In Vitro: DMSO: ≥ 100 mg/mL (321.20 mM; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO) * "≥" means soluble, but saturation unknown. |
| Storage | Powder: -20°C, 3 years; 4°C, 2 years. In solvent: -80°C, 2 years; -20°C, 1 year. |
| Shipping | Room temperature in continental US; may vary elsewhere. |
Biological Activity
IC50 & Target[1]
|
CK1δ 1 μM (IC50) |
CK1α1 16 μM (IC50) |
Literature Cited
Sources cited in this description and in the In Vitro & In Vivo Data tab. Peer-reviewed publications that used this product are listed under References.
Safety
For Research Use Only. Not for use in diagnostic or therapeutic procedures, and not for human or veterinary use. Handle in accordance with the Safety Data Sheet and your institution's chemical hygiene plan.
In Vitro
| Solvent | Solubility | Notes |
|---|---|---|
| DMSO | ≥ 100 mg/mL (321.20 mM) | use freshly opened DMSO (absorbed moisture lowers solubility) |
Aliquot the stock solution and store it at -80°C (up to 2 years) or -20°C (up to 1 year); avoid repeated freeze-thaw cycles.
In Vivo
Choose the formulation that suits the animal model and route of administration; percentages are volume ratios of the final working solution. Start from a clear DMSO stock (see In Vitro above), add the co-solvents one at a time in the order listed, mixing after each addition, and prepare the working solution fresh on the day of dosing. If precipitation or phase separation occurs, gentle warming or sonication can help.
Protocol 1
| Composition | 10% DMSO + 40% PEG300 + 5% Tween-80 + 45% saline |
|---|---|
| Result | ≥ 2.5 mg/mL (8.03 mM); clear solution |
| How to prepare | Gives a clear solution at ≥ 2.5 mg/mL (saturation not determined). For 1 mL of working solution: add 100 μL DMSO stock (25.0 mg/mL) to 400 μL PEG300; then 50 μL Tween-80; then 450 μL saline to bring the volume to 1 mL. Saline: dissolve 0.9 g sodium chloride in ddH2O and make up to 100 mL. |
Data provided by the manufacturer.
In Vitro
IC261 is a selective, ATP-competitive CK1 inhibitor, and its IC50 values are 1 μM for Ckiδ, 1 μM for Ckiε, and 16 μM for Ckiα1. Activity against PKA, p34cdc2, and p55fyn is lower (IC50s > 100 μM)[1]. In AC1-M88 cells, IC261 triggers mitotic arrest, spindle defects, and centrosome amplification. At 1 μM, IC261 raises the proportion of G2/M cells after 12 h and leads to cell death at 24 h in AC1-M88 cells. IC261 (1 μM) also triggers apoptosis in extravillous trophoblast hybrid cells[2]. At 1.25 μM, IC261 suppresses proliferation of several pancreatic tumor cell lines: ASPC-1, BxPc3, Capan-1, Colo357, MiaPaCa-2, Panc1, Panc89, PancTu-1 and PancTu-2. Pancreatic tumor cells also show enhanced CD95-mediated apoptosis specifically in the presence of IC261 (1.25 μM)[3].
In Vivo
In SCID mice, IC261 (20.5 mg/kg) slows the growth of PancTu-2 tumors, lowers the levels of several anti-apoptotic proteins (CK1δ/ε, KRAS, and IL6), and raises p21, ATM, CHEK1 and STAT1[3].
Data provided by the manufacturer. Numbered citations refer to the Literature Cited list in the product description.
Kinase Assay[1]
Assay casein kinase activity at 37°C. The standard 40 μL reaction contains 25 mM 2-(N-morpholino)ethanesulfonic acid (pH 6.5), 50 mM NaCl, 15 mM MgCl2, 2 mg/mL casein, and 2 mM EGTA, with 100 μM [γ-32P]ATP (100-400 cpm/pmol). Measure initial velocities in duplicate with ATP as the varied substrate, then calculate the kinetic constants and their standard errors. To determine inhibitor potency (IC50), keep [γ -32P]ATP constant (10 μM) and vary the IC261 concentration (0.1, 0.3, 1, 3, and 10 μM). To assess kinetic mechanism, keep the inhibitors constant (IC261, 20 μM; IC3608, 100 μM) and vary [γ -32P]ATP as above. To screen small molecule libraries, assay the CK1 isoforms (Ckiα1, δ, and ε) with casein at 10 mg/mL and [γ -32P]ATP held constant at 2 μM or 1 mM[1].
Cell Assay[2]
Human extravillous trophoblast cells leave the cell cycle irreversibly and die when separated from their natural extracellular matrix. Use the cell line AC1-M88 for in vitro experiments; it is generated by fusing extravillous trophoblasts with AC1-1. Grow cells in DMEM (CV-1) or DMEM/F-12 (AC1-M88) medium with 10% fetal calf serum (FCS), at 37°C, in a humidified atmosphere of 5% CO2. As indicated, γ-irradiate cells with 5 Gy and harvest at the given time points for western blot analysis; incubate for 12 h with 1 μM IC261 or 0.4 μM nocodazole and then fix for immunofluorescence analysis; or treat with 1 μM IC261 and either fix for flow cytometric analysis or lyse for western blot analysis at the indicated time points. Dissolve IC261 and nocodazole in DMSO as stock solutions (25 and 10 mM, respectively), and treat control cells with 0.004% DMSO. For immunocytochemistry, grow cells on coverslips, treat with methanol (−20°C) for 5 min, then with acetone (−20°C) for 20-30 s before immunocytochemical detection[2].
Animal Administration[3]
Resuspend five million PancTu-1 cells in 100 μL of 50% Matrigel and 50% DMEM/RPMI-1640 (1:1), and inject into the dorsolateral site of 6-week-old C.B-17/IcrHsd-scid-bg mice. After 17 days, randomize the mice into a control group (n = 5), an IC261 treatment group (n = 5), a gemcitabine group (n = 5), and an IC261/gemcitabine group (n = 5). Inject daily for 8 days with dimethylsulfoxide (DMSO; control group), IC261 (20.5 mg/kg), gemcitabine (0.6 mg/kg) alone, or the combination (20.5 mg/kg IC261/0.6 mg/kg gemcitabine) in the treatment groups. Sacrifice the mice by CO2 asphyxiation the day after the last treatment. Measure tumors before and during treatment. At the end, excise the tumors, measure and weigh them, and either fix in formalin or shock freeze. Calculate tumor volume with the rotational ellipsoid formula (length × height × width × 0.5236)[3].
Data provided by the manufacturer. Numbered citations refer to the Literature Cited list in the product description.
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IC261, a specific inhibitor of CK1δ/ε, promotes aerobic glycolysis through p53-dependent mechanisms in colon cancer. Int J Biol Sci 2020 Jan 17;16(5):882-892. PMID: 32071557
A Rationale for Drug Design Provided by Co-Crystal Structure of IC261 in Complex with Tubulin. Molecules 2021 Feb 10;26(4):946. PMID: 33579052
rs2253820 Variant Controls Blood Pressure Dip After Stroke by Increasing CLOCK-BMAL1 Expression. Transl Stroke Res 2023 Aug;14(4):472-489. PMID: 35870088
Phosphorylation of T425 and methylation of R426 synergistically regulate IBDV VP1 function and viral replication. Vet Microbiol 2026 Feb:313:110871. PMID: 41506171
