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Research Area
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Description
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Solid tumours,Multiple myeloma , Giant lymph node hyperplasia |
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Biological Activity
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Description
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CX-4945 is a potent and selective inhibitor of CK2α and CK2α' with IC50 of 1 nM. |
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Targets
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CK2α |
CK2α' |
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IC50 |
1 nM |
1 nM [1] |
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In Vitro
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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] |
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In Vivo
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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] |
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Clinical Trials
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A Phase I study of CX-4945 in patients with relapsed or refractory multiple myeloma is currently ongoing. |
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Features
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First clinical inhibitor of CK2 |
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Combination Therapy
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Description
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CX-4945 suppresses DNA repair response triggered by Gemcitabine and Cisplatin, and thus synergizes with these agents in models of ovarian cancer. [3] Combination of CX-4945 with Erlotinib results in enhanced attenuation of the PI3K-Akt-mTOR pathway, an increase in apoptosis, synergistic killing of cancer cells in vitro, and improved antitumor efficacy in vivo. [4] |
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Protocol
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Kinase Assay
[2]
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| 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. |
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Cell Assay
[1]
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| 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 |
| Methods |
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. |
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Animal Study
[1]
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| Animal Models |
Female immunocompromised mice CrTac:Ncr-Foxn1nu injected with BxPC-3 or BT-474 cells |
| Formulation |
Dissolved in DMSO, and diluted in PBS |
| Doses |
25 or 75 mg/kg |
| Administration |
Oral gavage twice daily |
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References |
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[1] Siddiqui-Jain A, et al. Cancer Res, 2010, 70(24), 10288-10298.
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[2] Pierre F, et al. J Med Chem, 2011, 54(2), 635-654.
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[3] Siddiqui-Jain A, et al. Mol Cancer Ther, 2012, 11(4), 994-1005.
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[4] Bliesath J, et al. Cancer Lett, 2012, 322(1), 113-118.
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