CX-4945 (Silmitasertib)

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S2248

2mg~100mg

Brand

Selleckchem

Description

CX-4945 (Silmitasertib)

Catalog No.S22484 Product Citations

CX-4945 is a potent and selective inhibitor of CK2 (casein kinase 2) with IC50 of 1 nM, less potent to Flt3, Pim1 and CDK1 (inactive in cell-based assay). Phase 1.

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Biological Activity

Description	CX-4945 is a potent and selective inhibitor of CK2 (casein kinase 2) with IC50 of 1 nM, less potent to Flt3, Pim1 and CDK1 (inactive in cell-based assay). Phase 1.
Targets	CK2α	CK2α’
IC50	1 nM	1 nM [1]
In vitro	CX-4945 is selective for CK2, as it only inhibits 7 of the 238 kinases by more than 90% at concentration of 0.5 μM, which is 500-fold greater than the IC50 of CK2. Although in cell-free systems CX-4945 inhibits FLT3, PIM1, and CDK1 with IC50 of 35 nM, 46 nM, and 56 nM, respectively, CX-4945 treatment at 10 μM is inactive against FLT3, PIM1, and CDK1 in cell-based functional assays. CX-4945 exhibits a broad spectrum of antiproliferative activity, and the breast cancer cell lines displays the widest range of sensitivity to CX-4945 with EC50 of 1.71-20.01 μM. The antiproliferative activity of CX-4945 correlates with CK2α mRNA and protein levels but not the CK2α’ catalytic subunit, the regulatory CK2β subunit, and the PI3K/Akt or PTEN mutational status. CX-4945 inhibits PI3K/Akt signaling by directly blocking the phosphorylation of Akt at Serine 129 by CK2 rather than through activation of PTEN. CX-4945 treatment causes reduced phosphorylation of p21 (T145), increased levels of total p21 and p27, and induction of caspase 3/7 activity. CX-4945 treatment induces a G2/M cell-cycle arrest in BT-474 cells and a G1 arrest in BxPC-3 cells. CX-4945 inhibits HUVEC proliferation, migration, and tube formation with IC50 of 5.5 μM, 2 μM, and 4 μM, respectively. Under hypoxic conditions in BT-474 and BxPC-3 cells, CX-4945 treatment prevents downregulation of p53 and pVHL and reduces activation of HIF-1α transcription. [1] CX-4945 potently inhibits endogenous intracellular CK2 activity with IC50 of 0.1 μM in Jurkat cells. [2]
In vivo	Oral administration of CX-4945 at 25 mg/kg or 75 mg/kg twice daily displays potent antitumor activity in the BT-474 model, with TGI of 88% and 97%, respectively, and 2 of 9 animals in each group showing more than 50% reduction in tumor size compared with the initial tumor volume. In the BxPC-3 model, CX-4945 treatment at 75 mg/kg twice daily shows 93% TGI with 3 animals having no evidence of tumor remaining at the end of the treatment period. [1] In PC3 xenograft model, administration of CX-4945 at 25 mg/kg, 50 mg/kg, or 75 mg/kg causes tumor growth inhibition with TGI of 19%, 40%, and 86%, respectively. [2]
Features	First clinical inhibitor of CK2.

Protocol(Only for Reference)

Kinase Assay: [2]

CK2 Kinase Assay	CX-4945 is added at a volume of 10 μL to a reaction mixture comprising 10 μL of assay dilution buffer (ADB; 20 mM MOPS, pH 7.2, 25 mM β-glycerolphosphate, 5 mM EGTA, 1 mM sodium orthovanadate, and 1 mM dithiothreitol), 10 μL of substrate peptide (RRRDDDSDDD, dissolved in ADB at a concentration of 1 mM), 10 μL of recombinant human CK2 (ααββ-holoenzyme, 25 ng dissolved in ADB). Reactions are initiated by the addition of 10 μL of ATP solution (90% 75 mM MgCl2, 75 μM ATP (final ATP concentration=15 μM) dissolved in ADB; 10% [γ-33P]ATP (stock 1 mCi/100 μL; 3000 Ci/mM and maintained for 10 minutes at 30 °C. The reactions are quenched with 100 μL of 0.75% phosphoric acid and then transferred to and filtered through a phosphocellulose filter plate. After washing each well five times with 0.75% phosphoric acid, the plate is dried under vacuum for 5 minutes and, following the addition of 15 μL of scintillation fluid to each well, the residual radioactivity is measured using a Wallac luminescence counter. The IC50 values are derived from eight concentrations of CX-4945 over a range of 0.0001 μM to 1 μM.

CK2 Kinase Assay

CX-4945 is added at a volume of 10 μL to a reaction mixture comprising 10 μL of assay dilution buffer (ADB; 20 mM MOPS, pH 7.2, 25 mM β-glycerolphosphate, 5 mM EGTA, 1 mM sodium orthovanadate, and 1 mM dithiothreitol), 10 μL of substrate peptide (RRRDDDSDDD, dissolved in ADB at a concentration of 1 mM), 10 μL of recombinant human CK2 (ααββ-holoenzyme, 25 ng dissolved in ADB). Reactions are initiated by the addition of 10 μL of ATP solution (90% 75 mM MgCl2, 75 μM ATP (final ATP concentration=15 μM) dissolved in ADB; 10% [γ-33P]ATP (stock 1 mCi/100 μL; 3000 Ci/mM and maintained for 10 minutes at 30 °C. The reactions are quenched with 100 μL of 0.75% phosphoric acid and then transferred to and filtered through a phosphocellulose filter plate. After washing each well five times with 0.75% phosphoric acid, the plate is dried under vacuum for 5 minutes and, following the addition of 15 μL of scintillation fluid to each well, the residual radioactivity is measured using a Wallac luminescence counter. The IC50 values are derived from eight concentrations of CX-4945 over a range of 0.0001 μM to 1 μM.

Cell Assay: [1]

Cell lines	SKBr3, MDA-MB-453, BT-474, ZR-75-1, MDA-MB-231, MDA-MB-468, T47D, MCF 7, Hs578T, MDA-MB-361, UACC-812, et al.
Concentrations	Dissolved in DMSO, final concentrations ~100 μM
Incubation Time	4 days
Method	Cells are seeded at a density of 3,000 cells per well 24 hours prior to treatment, in appropriate media, and then treated with various concentrations of CX-4945. Suspensions cells are seeded and treated on the same day. Following 4 days of incubation, Alamar Blue (20 μL, 10% of volume per well) is added and the cells are further incubated at 37 °C for 4-5 hours. Fluorescence with excitation wavelength at 530-560 nm and emission wavelength at 590 nm is measured.

Animal Study: [1]

Animal Models	Female immunocompromised mice CrTac:Ncr-Foxn1nu injected with BxPC-3 or BT-474 cells
Dosages	25 or 75 mg/kg
Administration	Oral gavage twice daily

References

Chemical Information

Download CX-4945 (Silmitasertib) SDF

Molecular Weight (MW)	349.77
Formula	C19H12ClN3O2
CAS No.	1009820-21-6

Storage	3 years -20â„ƒPowder
Storage	6 months-80â„ƒin DMSO
Syonnyms	N/A

Solubility (25°C) *	In vitro	DMSO	16 mg/mL (45 mM)
		Water	<1 mg/mL (<1 mM)
		Ethanol	<1 mg/mL (<1 mM)
* <1 mg/ml means slightly soluble or insoluble. * Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.