Akt1 (IC50 = 8 nM); Akt2 (IC50 = 12 nM); Akt3 (IC50 = 65 nM)

Kinase Assay: Akt kinases are assayed by a GSK-derived biotinylated peptide substrate. The extent of peptide phosphorylation is determined by Homogeneous Time Resolved Fluorescence (HTRF) using a lanthanide chelate (Lance)-coupled monoclonal antibody specific for the phosphopeptide in combination with a streptavidin-linked allophycocyanin (SA-APC) fluorophore which will bind to the biotin moiety on the peptide. When the Lance and APC are in proximity, a non-radiative energy transfer takes place from the Lance to the APC, followed by emission of light from APC at 655 nm. Working Solution: 100X protease inhibitor cocktail (PIC): 1mg/mL benzamidine, 0.5 mg/mL pepstatin, 0.5 mg/mL leupeptin, 0.5 mg/mL aprotinin; 10X assay buffer: 500 mM HEPES, pH7.5, 1% PEG, 16.6 mM EDTA, 1 mM EGTA, 1% BSA, 20 mM 9-glycerol phosphate; Quench buffer 50 mM HEPES pH 7.3, 16.6 mM EDTA, 0.1% BSA, 0.1% Triton X-100, 0.17 nM labeled monoclonal antibody, 0.0067 mg/mL SA-APC; ATP/MgCl2working solution: 1X Assay buffer, 1 mM DTT, 1X PIC, 5% glycerol, active Akt; Peptide working solution: 1X Assay buffer, 1 mM DTT, 1X PIC, 5% glycerol, 2 TM GSK biotinylated peptide. The reaction is assembled by adding 16 µL of ATP/MgCl2working solution to the appropriate wells. MK-2206 or vehicle (1.0 µL) is added followed by 10 µL of peptide working solution. The reaction is started by adding 13 μL of the enzyme working solution and mixing. The reaction is allowed to proceed for 50 min and then stopped by the addition of 60 µL HTRF quench buffer. The stopped reactions are incubated at room temperature for at least 30 min and then read in the instrument.Cell Assay: MK-2206 is dissolved in DMSO as a stock solution and diluted by culture media before use. Cells (A431, HCC827, NCI-H292, NCI-H358, NCI-H23, NCI-H1299, Calu-6 and NCI-H460 cells) are seeded at a density of 2-3 × 103in 96-well plates and incubated for 24 hours. Then MK-2206 (0, 0.3, 1 and 3 μM) is added to the cells. Cell proliferation is determined after 72 or 96 hours.MK-2206 is an allosteric inhibitor and is activated by the pleckstrin homology domain. MK-2206 inhibits auto-phosphorylation of both Akt T308 and S473. MK-2206 also prevents Akt-mediated phosphorylation of downstream signaling molecules, including TSC2, PRAS40 and ribosomal S6 proteins. MK-2206 inhibits Ras wild-type (WT) cell lines (A431, HCC827, and NCI-H292) more potently when compared to Ras-mutant cell lines (NCI-H358, NCI-H23, NCI-H1299, and Calu-6). MK-2206 also shows synergistic responses in combination with cytotoxic agents such as erlotinib or lapatinib in lung NCI-H460 or ovarian A2780 tumor cells.MK-2206 or siRNA-mediated Akt inhibition strongly activates autophagy in human glioma cells. However, eukaryotic elongation factor-2 (eEF-2) silencing suppresses MK-2206-induced-autophagy, with a promotion of apoptotic cell death.

MK-2206 shows 60% TGI and inhibits more than 70 % of phospho-Akt1/2 (T308 and S473) in A2780 ovarian cancer xenografts at a dose of 240 mg/kg. MK-2206 exhibits significant antitumor activity in NCI-H292 xenograft in combination with erlotinib or lapatinib.

Akt kinases are assayed by a GSK-derived biotinylated peptide substrate. By combining a lanthanide chelate (Lance)-coupled monoclonal antibody that is specific for the phosphopeptide with a streptavidin-linked allophycocyanin (SA-APC) fluorophore that will bind to the peptide's biotin moiety, homogeneous time-resolved fluorescence (HTRF) can be used to determine the degree of phosphorylation. When the Lance and APC are close together, the Lance transfers non-radiative energy to the APC, and the APC then emits light at a wavelength of 655 nm. Protease inhibitor cocktail (PIC) 100X: Benzamidine 1 mg/mL, Pepstatin 0.5 mg/mL, Leupeptin 0.5 mg/mL, Aprotinin 0.5 mg/mL; 10X assay reagent: 20 mM 9-glycerol phosphate, 50 mM HEPES, pH 7.3, 16.6 mM EDTA, 0.1% BSA, 0.1% Triton X-100, 0.17 nM labeled monoclonal antibody, and 0.0067 mg/mL SA-APC make up the quench buffer. Working solution for the ATP/MgCl2 assay: 1X Assay buffer, 1 mM DTT, 1X PIC, 5% glycerol, active Akt; Peptide working solution: 2 TM GSK biotinylated peptide, 1X Assay buffer, 1 mM DTT, 1X PIC, and 5% glycerol. The reaction is assembled by adding 16 µL of ATP/MgCl2 working solution to the appropriate wells. MK-2206 or vehicle (1.0 µL) is added followed by 10 µL of peptide working solution. The reaction is started by adding 13 μL of the enzyme working solution and mixing. The reaction is allowed to proceed for 50 min and then stopped by the addition of 60 µL HTRF quench buffer. The stopped reactions are incubated at room temperature for at least 30 min and then read in the instrument.

In 96-well plates, 2-3 × 103 cells are seeded, and the plates are then incubated for 24 hours. After that, the cells receive additions of MK-2206 (0, 0.3, 1 and 3 μM). 72 or 96 hours later, cell proliferation is assessed.

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Cell proliferation assay and determination of combination index[2]
Cells were seeded at a density of 2 to 3 × 103 per well in 96-well plates. Twenty-four hours after plating, varying concentrations of the drug, either as a single agent or in combination, were added to the wells. Cell proliferation was determined by using the CellTiter-Glo assay at 72 or 96 hours after dosing. The nature of the drug interaction was evaluated by using the combination index (CI) according to the method of Chou and Talalay. A commercial software package was obtained from Calcusyn. In the combination with docetaxel, we tested three treatment sequences: (a) MK-2206 followed by docetaxel—cells were exposed to MK-2206 for 24 hours, and then after washout of MK-2206, cells were treated with docetaxel for an additional 72 hours; (b) docetaxel followed by MK-2206—cells were exposed to docetaxel for 24 hours, and then after washout of docetaxel, cells were treated with MK-2206 for an additional 72 hours; and (c) concurrent treatment—cells were exposed to both MK-2206 and docetaxel for 72 hours.[2]
LN229 and T98G cells cultured in medium supplemented with 10% fetal bovine serum were treated with a series of concentrations of MK-2206, and the levels of phospho-eEF-2 and eEF-2 were examined by Western blot. Tubulin was used as a loading control. (B) LN229 and T98 G cells were transfected with a non-targeting RNA or a siRNA targeting eEF-2 kinase, followed by treatment with MK-2206 for 24h. eEF-2 kinase, LC3 and p62 were examined by Western. Tubulin was used as a loading control. [3]
Effect of MK-2206 on autophagy in human glioma cells[3]

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(A) LN229 and T98G cells cultured in medium supplemented with 10% fetal bovine serum were treated with MK2206 for 24h, the level of LC3 was examined by Western blot. (B) LN229 and T98G cells were treated with MK2206 for 24h in the absence or presence of 10 nM of bafilomycin A1, and the level of LC3 was examined by Western blot. Tubulin was used as a loading control. (C) LN229 and T98G cells were transfected with a GFP-LC3 plasmid, followed by treatment with 2.5 or 5 μM MK2206 for 24h. At the end of treatment, the cells were inspected at 60x magnification for numbers of GFP-LC3 puncta. Bars are the quantification of the percentage of cells with 10 or more GFP-LC3 puncta. At least 100 cells were scored in each treatment. * p< 0.05; * *p < 0.01, t-test, MK-2206 vs. vehicle. (D) LN229 and T98G cells were treated with 10 μM of MK-2206 for 24h, and the AO fluorescent intensity in the treated cells was analyzed by flow cytometry. (E) LN229 cells treated with MK-2206 (2.5 μM) or vehicle were harvested by trypsinization, fixed and embedded in spur resin. Ninety nm thin sections were cut and examined at 80 Kv with a JEOL 1200EX transmission electron microscope. Arrows indicate autophagic vacuoles.

SK-OV-3, NCI-H292, HCC70, PC-3, and NCI-H460 models in male CD1-nude mice;

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Efficacy studies in mouse xenograft models[2] Human tumor cells were suspended in 50% Matrigel (BD) and 50% PBS and were injected s.c. into the left flank of the mice.[2]
When the mean tumor size reached 0.13 cm3 for the SK-OV-3 or 0.2 cm3 for the NCI-H292, HCC70, PC-3, and NCI-H460 models, the mice were randomized into control and treatment groups with approximately equivalent ranges of tumor volume between groups (n = 5 animals per group). The following vehicles were used to dose the compounds: 30% Captisol for MK-2206; 0.5% methylcellulose + 0.1% Tween 80 for erlotinib; distilled water for lapatinib; 0.73% ethanol in saline for docetaxel; and saline for carboplatin and gemcitabine. The control group received vehicle only. Tumor volume was measured with calipers twice a week. Animal body weight and physical signs were monitored during the experiments.

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Briefly, 4–6 week-old female nude mice were inoculated subcutaneously with LN229 cells (5 × 106 cells/per site) with or without silencing of eEF-2 kinase. At day 7 after inoculation, MK-2206 (120 mg/kg, p.o.) was administered to the tumor-bearing mice. Tumors were harvested 24 h post drug administration for analysis of autophagy and apoptosis. Apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling tetramethylrhodamine red apoptosis kit from Roche, and using Western blot analysis of cleaved caspase 3. Autophagy was detected by Western blot analysis of LC3 II.[3]

[1]. Abstract #DDT01-1: MK-2206: A potent oral allosteric AKT inhibitor

[2]. Mol Cancer Ther. 2010 Jul;9(7):1956-67.

[3]. Cancer Res. 2011 Apr 1;71(7):2654-63.

MK-2206 is an organic heterocyclic tricyclic compound with the structure [1,2,4]triazolo[3,4-f][1,6]naphthidine-3(2H)-one, substituted at positions 8 and 9 with 4-(1-aminocyclobutyl)phenyl and phenyl, respectively. It is an EC 2.7.1.137 (phosphatidylinositol 3-kinase) inhibitor. Its function is similar to that of 1,6-naphthidine.
The Akt inhibitor MK2206 is an orally bioavailable allosteric inhibitor of serine/threonine protein kinase Akt (protein kinase B) with potential antitumor activity. The Akt inhibitor MK2206 binds to and inhibits Akt activity in a non-ATP-competitive manner, which may lead to the inhibition of the PI3K/Akt signaling pathway and tumor cell proliferation, and induce tumor cell apoptosis. Activation of the PI3K/Akt signaling pathway is generally associated with tumorigenesis, while dysregulation of the PI3K/Akt signaling pathway may lead to tumor resistance to multiple antitumor drugs. MK-2206 is currently being investigated in two Phase I clinical trials, one in healthy volunteers (HV) and the other in cancer patients. In the first-in-human trial in healthy volunteers, 24 healthy male subjects participated in this Phase I randomized, double-blind, placebo-controlled, sequential, multi-cycle, escalating single oral dose study. Eight subjects were randomized to three groups (Group A, Group B, and Group C). In each treatment cycle, the same six subjects in each group received MK-2206 after an overnight fast, and two subjects received placebo. Volunteers received a single dose ranging from 0.25 to 100 mg, and blood samples were collected before and at pre-defined post-dose time points for pharmacokinetic and pharmacodynamic (whole blood phosphorylated Akt inhibition) analysis. Results showed that single doses of up to 100 mg of MK-2206 were generally well tolerated. No serious clinical or laboratory adverse reactions were reported. The most common adverse reactions were headache, common cold, and diarrhea. One subject withdrew from the study due to a clinical adverse reaction of blurred vision, but the symptom resolved. Laboratory safety tests and electrocardiographic assessments revealed no clinically significant changes. None of the subjects developed clinically significant hyperglycemia or hyperinsulinemia. Preliminary pharmacokinetic results showed rapid absorption of oral MK-2206, with a median time to peak concentration (Tmax) of 6 to 8 hours and a median half-life of 55 to 78 hours. AUC_0-t and C_max were dose-proportional across the 2 mg to 100 mg dose range. Preliminary pharmacodynamic results showed that single doses of 40 mg, 80 mg, and 100 mg MK-2206 resulted in stronger Akt inhibition in whole blood than placebo. Peak Akt inhibition was reached at 6 hours post-dose in the 80 mg and 100 mg dose groups, with a mean plasma concentration >65 nM. Akt inhibition was observed within 2 to 24 hours. In conclusion, MK-2206 was well-tolerated in healthy subjects after a single dose. The pharmacokinetic profile of MK-2206 is dose-proportional and there is clear evidence of Akt inhibition. Clinical development of MK-2206 in cancer patients is underway, with a focus on tumors with PI3K pathway activation events. [1] Serine/threonine kinase Akt is a key signaling node downstream of phosphatidylinositol-3-kinase and plays an important role in promoting cell survival and inhibiting apoptosis. Akt inhibitors may be particularly effective against cancers associated with enhanced Akt signaling and reduced sensitivity to cytotoxic drugs or receptor tyrosine kinase inhibitors. We evaluated the efficacy of a novel allosteric Akt inhibitor, MK-2206, in combination with several anticancer drugs. In vitro experiments showed that MK-2206 synergistically inhibited the proliferation of human cancer cell lines when used in combination with molecularly targeted drugs such as erlotinib (an epidermal growth factor receptor inhibitor) or lapatinib (a dual epidermal growth factor receptor/human epidermal growth factor receptor 2 inhibitor). Complementary inhibition of erlotinib-insensitive Akt phosphorylation by MK-2206 is one of its synergistic mechanisms, and this synergistic effect has been observed even in erlotinib-insensitive cell lines. In lung cancer NCI-H460 or ovarian cancer A2780 cells, MK-2206 also showed synergistic effects when used in combination with cytotoxic agents such as topoisomerase inhibitors (doxorubicin, camptothecin), antimetabolites (gemcitabine, 5-fluorouracil), antimicrotubule agents (docetaxel), and DNA cross-linking agents (carboplatin). The synergistic effect with docetaxel depends on the order of administration; administration of MK-2206 before docetaxel administration is ineffective. MK-2206 inhibits carboplatin- and gemcitabine-induced Akt phosphorylation. In vivo, the tumor-suppressive activity of MK-2206 when used in combination with these drugs is significantly stronger than that of the drugs used alone. These findings suggest that Akt inhibition may enhance the efficacy of existing anticancer therapies; therefore, MK-2206 holds promise as an effective treatment for cancer patients receiving these cytotoxic and/or molecularly targeted therapies. [2]

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Inhibition of the survival kinase Akt can induce apoptosis and has been found to activate autophagy, which may interfere with tumor attack. In this study, we investigated the mechanism by which MK-2206 (the first small allosteric molecule inhibitor of Akt to enter clinical development) regulates apoptosis and autophagy in tumor cells by modulating Akt. In human glioma cells, Akt inhibition mediated by MK-2206 or siRNA significantly activated autophagy, while silencing eukaryotic elongation factor-2 (eEF-2) kinase (a protein synthesis regulator) attenuated this autophagic response. eEF-2 silencing inhibited MK-2206-induced autophagy while also promoting apoptosis. Similarly, siRNA-mediated inhibition of eEF-2 kinase enhanced the efficacy of MK-2206 against glioma cells. In summary, these results suggest that inhibiting eEF-2 kinase to reduce autophagy and enhance apoptosis can modulate the sensitivity of glioma cells to Akt inhibitors. Our findings suggest that targeting eEF-2 kinase may enhance the antitumor efficacy of Akt inhibitors such as MK-2206. [3]

C25H21N5O

407.46714

407.175

C, 73.69; H, 5.19; N, 17.19; O, 3.93

1032349-93-1

MK-2206 dihydrochloride;1032350-13-2;MK-2206;1032349-77-1

24964624

Solid powder

5.355

2

4

3

31

760

0

C1=CC=C(C=C1)C2=C(C3=CC=C(C=C3)C4(CCC4)N)N=C5C=CN6C(=NN=C6O)C5=C2

ULDXWLCXEDXJGE-UHFFFAOYSA-N

InChI=1S/C25H21N5O/c26-25(12-4-13-25)18-9-7-17(8-10-18)22-19(16-5-2-1-3-6-16)15-20-21(27-22)11-14-30-23(20)28-29-24(30)31/h1-3,5-11,14-15H,4,12-13,26H2,(H,29,31)

1,2,4-Triazolo(3,4-f)(1,6)naphthyridin-3(2H)-one, 8-(4-(1-aminocyclobutyl)phenyl)-9-phenyl-

MK 2206; MK-2206; 1032349-93-1; 8-[4-(1-aminocyclobutyl)phenyl]-9-phenyl-2H-[1,2,4]triazolo[3,4-f][1,6]naphthyridin-3-one; MK 2206; MK-2206 free base; MK-2206 (free base); 51HZG6MP1K; MK2206

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)

Typically soluble in DMSO (e.g. > 10 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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