CK2α 36 nM (IC50) CK2α' 16 nM (IC50)
SGC-CK2-1 targets CK2α (CSNK2A1) with enzymatic IC50 = 4.2 nM (radiometric assay at Km ATP) and cellular nanoBRET IC50 = 36 nM in HEK-293 cells; targets CK2α' (CSNK2A2) with enzymatic IC50 = 2.3 nM and cellular nanoBRET IC50 = 16 nM.
Off-target inhibition: DYRK2 enzymatic IC50 = 440 nM, DYRK2 cellular nanoBRET IC50 = 3.7 μM; HIPK2 enzymatic IC50 = 3400 nM; HIPK1 enzymatic IC50 = 3700 nM; HIPK3 enzymatic IC50 = 8100 nM; PLK4 enzymatic IC50 >10,000 nM; DRAK1 enzymatic IC50 >10,000 nM; MEK5 shows 0% inhibition at 1 μM. [1]

SGC-CK2-1 has IC50 values of 2.3 and 4.2 nM, respectively, for inhibiting CSNK2A2 and CSNK2A1[1]. A 3.7 μM IC50 value is used by SGC-CK2-1 to inhibit DYRK2[1]. MV4-11, MOLM-13, OCI-LY19, OCI-AML5, and blood U-937 cells are all inhibited by SGC-CK2-1, with IC50 values of 120, 690, 750, 760, and 810 nM, respectively. Detroit562 Head/Neck cells are inhibited by SGC-CK2-1 at a 550 nM IC50. An IC50 of 550 nM is required for SGC-CK2-1 to inhibit Lung NCI-H2286 cells. An IC50 of 730 nM is required for SGC-CK2-1 to inhibit Brain SK-N-MC cells. A dose of 810 nM is required for SGC-CK2-1 to inhibit Breast BT-20 cells. 830 nM is the IC50 at which SGC-CK2-1 inhibits Skin A375 cells. Utilizing an IC50 of 860 nM, SGC-CK2-1 suppresses stomach SNU-1 cells. An IC50 of 920 nM is required for SGC-CK2-1 to inhibit Duodenum Hutu 80 cells[1].

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SGC-CK2-1 antiproliferative activity: In HCT-116 colorectal carcinoma cells, no antiproliferative activity up to 10 μM (GI50 >10 μM). In U-87 MG glioblastoma cells, no antiproliferative activity up to 10 μM. In a panel of 140 cancer cell lines, only U-937 (pro-monocytic human histiocytic lymphoma) showed IC50 below 500 nM (exact IC50 not specified). In NCI60 panel at 10 μM, SGC-CK2-1 induced minor lethality (8-22%) in A498, HS 578T, RXF 393, and SNB-75 cells; and inhibited growth >90% in HL-60, MCF7, MDA-MB-468, T-47D (IC50 values 1.2-2.8 μM).
Caspase 3/7 activation: In U-87 MG cells, SGC-CK2-1 did not activate caspase 3/7 at concentrations up to 10 μM at multiple time points.
Western blot (AKT S129 phosphorylation): In HCT-116 cells treated with SGC-CK2-1 for 3h or 24h, a dose-dependent decrease in AKT S129 phosphorylation was observed; at 10 μM strong inhibition, at 0.01 μM minimal effect. GAPDH loading control.
Western blot (EIF2S2 pS2): In U2OS cells expressing tetracycline-inducible wild-type CK2α-HA, SGC-CK2-1 (0.5-10 μM, 24h) dose-dependently inhibited EIF2S2 pS2 phosphorylation. In cells expressing inhibitor-resistant double mutant (DM, V66A/I174A) CK2α-HA, SGC-CK2-1 had no effect on EIF2S2 pS2. CX-4945 inhibited both. SGC-CK2-1 showed robust inhibition at 10x lower concentration than CX-4945. [1]

scanMAX kinase binding assay: Profiled against 403 wild-type human kinases at 1 μM compound concentration. Percent inhibition values were determined. For SGC-CK2-1, only 3 kinases showed >90% inhibition at 1 μM.
Radiometric KinaseProfiler assay (Eurofins): Conducted at the Km of ATP in dose-response (9-point curve in duplicate) for CK2α and CK2α'. The peptide substrate used was RRRDDDSDDD. IC50 values were calculated. For SGC-CK2-1, CK2α IC50 = 4.2 nM, CK2α' IC50 = 2.3 nM. Off-target kinases (DYRK2, HIPK1, HIPK2, HIPK3, PLK4, DRAK1) were tested at Km ATP; IC50 values as reported.
LANCE assay: Used for MEK5 at a single concentration (10 μM) in duplicate. SGC-CK2-1 showed 0% inhibition at 1 μM. [1]

NanoBRET cellular target engagement assay: HEK-293 cells transiently expressing Nanoluciferase (Nluc)-tagged CK2α or CK2α' were used. Cells were treated with NanoBRET Tracer K5 (1.0 μM) and varying concentrations of SGC-CK2-1 for 2 hours. BRET signal was measured after adding NanoBRET NanoGlo substrate and extracellular NanoLuc inhibitor. IC50 values were calculated from dose-response curves. For CK2α: 36 nM; for CK2α': 16 nM.
AlamarBlue cell proliferation assay: HCT-116 or U-87 MG cells seeded at 2500 cells/well in 96-well plates, incubated overnight, then treated with 10-point dose response of SGC-CK2-1 (0.01-10 μM) for 72h. AlamarBlue reagent added, incubated 4h, fluorescence measured at 535/590 nm. GI50 calculated relative to staurosporine (10 μM) as min and DMSO as max.
Large panel antiproliferative assay (140 cell lines): Cells seeded in white flat-bottom clear-bottom multi-well plates, incubated overnight. SGC-CK2-1 was dosed in 8-point 3-fold dilutions from 3 μM to 0.9 nM (final DMSO 0.1%) using a Tecan dispenser. After 72h incubation, CellTiter-Glo reagent added, luminescence measured. IC50 calculated using GraphPad Prism with variable slope sigmoidal response model (bottom constraint 0% viability, top constraint 100% viability).
NCI60 panel: SGC-CK2-1 tested at single dose of 10 μM against 59 cancer cell lines. Percent growth of treated cells relative to control and time zero was reported, allowing detection of growth inhibition (0-100) and lethality (<0).
Caspase-Glo 3/7 assay: U-87 MG cells treated with SGC-CK2-1 up to 10 μM; assay performed according to manufacturer instructions. No activation observed.
Western blot (HCT-116): Cells seeded at 200,000 per well in 6-well plates, treated with SGC-CK2-1 (0.01-10 μM) for 3h or 24h. Lysed, protein quantified by BCA, separated on 4-12% Bis-Tris gradient gel, blotted onto PVDF membrane. Blocked with 5% BSA, incubated with anti-pAKT S129, anti-AKT1, anti-GAPDH, then HRP-conjugated secondary antibodies, developed with ECL substrate. Band intensities quantified.
Western blot (U2OS): FT-U2OS cells expressing tetracycline-inducible wild-type or DM (V66A/I174A) CK2α-HA. Induced with tetracycline (1 μg/mL) for 48h, then treated with SGC-CK2-1 (0.5-10 μM) for 24h. Immunoblotted for EIF2S2 pS2, total EIF2S2, and GAPDH. Infrared IRDye-labeled secondary antibodies used, quantified on LiCor Odyssey system. Residual CK2 activity calculated as percentage of DMSO control. [1]

[1]. Development of a potent and selective chemical probe for the pleiotropic kinase CK2. Cell Chem Biol. 2021 Apr 15;28(4):546-558.e10.

[2]. A New Chemical Probe Challenges the Broad Cancer Essentiality of CK2. Trends Pharmacol Sci. 2021 May;42(5):313-315.

SGC-CK2-1 is a pyrazolopyrimidine compound, specifically a derivative of pyrazolo[1,5-a]pyrimidine, with its 3, 5, and 7 positions substituted by a cyano, (4-methyl-3-propamidophenyl)nitroso, and cyclopropylnitroso, respectively. It is a highly efficient and selective chemical probe for detecting the pleiotropic kinase CK2. It is an EC 2.7.11.1 (non-specific serine/threonine protein kinase) inhibitor. SGC-CK2-1 belongs to the pyrazolopyrimidine class, nitrile class, secondary amino class, substituted aniline class, cyclopropane class, and secondary carboxamide class.

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SGC-CK2-1 is a pyrazolopyrimidine derivative (compound 24) designed from a library based on AstraZeneca's lead structure 17. It has a propionamide group at the 3-position, which contributes to its improved selectivity over analogs with acetamide or cyclopropanecarboxamide. The negative control compound SGC-CK2-1N (compound 32) was generated by global methylation of nitrogens, disrupting key hydrogen bonds and steric interactions, resulting in loss of CK2 binding (CK2α' nanoBRET IC50 >10 μM, no enzymatic activity). X-ray crystallography structure of CK2α in complex with SGC-CK2-1 (PDB code 6Z83) shows a Type I ATP-competitive binding mode with key hydrogen bonds to hinge region H115-V116 and interactions with the DWG motif and αC helix. SGC-CK2-1 shows 100-fold selectivity for CK2 over its most potently inhibited off-target DYRK2 in enzymatic assays (CK2 IC50 4.2 nM vs DYRK2 IC50 440 nM) and this selectivity is maintained in cells (nanoBRET CK2α' 16 nM vs DYRK2 3.7 μM). The compound challenges the paradigm that CK2 is broadly essential for cancer cell proliferation, as it lacks antiproliferative activity in most cancer cell lines, suggesting that previously reported antiproliferative effects of less selective CK2 inhibitors (e.g., CX-4945) are likely due to off-target kinase inhibition (e.g., DAPK family). Potential therapeutic applications beyond oncology include neurodegenerative diseases (Alzheimer's, Parkinson's, ALS, FTD) and viral infections (SARS-CoV-2) due to CK2's role in neuroinflammation and viral hijacking. [1]

C20H21N7O

375.427042722702

375.18

2470424-39-4

146681133

Off-white to light yellow solid powder

2.8

3

6

6

28

615

0

O=C(CC)NC1=C(C)C=CC(=C1)NC1C=C(N2C(=C(C#N)C=N2)N=1)NC1CC1

YKDZIFFKQUNVHH-UHFFFAOYSA-N

InChI=1S/C20H21N7O/c1-3-19(28)25-16-8-15(5-4-12(16)2)23-17-9-18(24-14-6-7-14)27-20(26-17)13(10-21)11-22-27/h4-5,8-9,11,14,24H,3,6-7H2,1-2H3,(H,23,26)(H,25,28)

N-[5-[[3-cyano-7-(cyclopropylamino)pyrazolo[1,5-a]pyrimidin-5-yl]amino]-2-methylphenyl]propanamide

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : 100 mg/mL (266.36 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.66 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.66 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)