|References on MK 2206:
1 . Simioni C, Neri LM, Tabellini G, Ricci F, Bressanin D, Chiarini F, Evangelisti C, Cani A, Tazzari PL, Melchionda F, Pagliaro P, Pession A, McCubrey JA, Capitani S, Martelli AM.Cytotoxic activity of the novel Akt inhibitor, MK-2206, in T-cell acute lymphoblastic leukemia.Leukemia. 2012 May 22.
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive neoplastic disorder arising from T-cell progenitors. T-ALL accounts for 15% of newly diagnosed ALL cases in children and 25% in adults. Although the prognosis of T-ALL has improved, due to the use of polychemotherapy schemes, the outcome of relapsed/chemoresistant T-ALL cases is still poor. A signaling pathway that is frequently upregulated in T-ALL, is the phosphatidylinositol 3-kinase/Akt/mTOR network. To explore whether Akt could represent a target for therapeutic intervention in T-ALL, we evaluated the effects of the novel allosteric Akt inhibitor, MK-2206, on a panel of human T-ALL cell lines and primary cells from T-ALL patients. MK-2206 decreased T-ALL cell line viability by blocking leukemic cells in the G(0)/G(1) phase of the cell cycle and inducing apoptosis. MK-2206 also induced autophagy, as demonstrated by an increase in the 14-kDa form of LC3A/B. Western blotting analysis documented a concentration-dependent dephosphorylation of Akt and its downstream targets, GSK-3α/β and FOXO3A, in response to MK-2206. MK-2206 was cytotoxic to primary T-ALL cells and induced apoptosis in a T-ALL patient cell subset (CD34(+)/CD4(-)/CD7(-)), which is enriched in leukemia-initiating cells. Taken together, our findings indicate that Akt inhibition may represent a potential therapeutic strategy in T-ALL.Leukemia advance online publication, 15 June 2012; doi:10.1038/leu.2012.136.
2 . Lai YC, Liu Y, Jacobs R, Rider MH.A novel PKB/Akt inhibitor, MK-2206, effectively inhibits insulin-stimulated glucose metabolism and protein synthesis in isolated rat skeletal muscle.Biochem J. 2012 Jul 13.
Protein kinase B (PKB) is a key component of insulin signalling. Defects in PKB activation lead to insulin resistance and metabolic disorders, whereas PKB over-activation has been linked to tumor growth. Small-molecule PKB inhibitors have thus been developed for cancer treatment but also represent useful tools to probe the roles of PKB in insulin action. Here we examined the acute effects of two allosteric PKB inhibitors, MK-2206 and Akti 1/2 (Akti) on PKB signalling in incubated rat soleus muscles. We also assessed the effects of the compounds on insulin-stimulated glucose uptake, glycogen and protein synthesis. MK-2206 dose-dependently inhibited insulin-stimulated PKB phosphorylation, PKBβ activity, and phosphorylation of PKB downstream targets (including glycogen synthase kinase-3a/b, proline-rich Akt substrate of 40 kDa and Akt substrate of 160 kDa). Insulin-stimulated glucose uptake, glycogen synthesis and glycogen synthase activity were also decreased by MK-2206 in a dose-dependent manner. Incubation with high doses of MK-2206 (10 μM) inhibited insulin-induced p70 ribosomal protein S6 kinase and eukaryotic initiation factor-4E binding protein-1 phosphorylation associated with increased eEF2 phosphorylation. By contrast, Akti only modestly inhibited insulin-induced PKB and mTOR signalling, with little or no effect on glucose uptake and protein synthesis. MK-2206, rather than Akti, would thus be the tool of choice for studying the role of PKB in insulin action in skeletal muscle. The data point to a key role for PKB in mediating insulin-stimulated glucose uptake, glycogen synthesis and protein synthesis in skeletal muscle.
3 . Pant A, Lee II, Lu Z, Rueda BR, Schink J, Kim JJ.Inhibition of AKT with the Orally Active Allosteric AKT Inhibitor, MK-2206, Sensitizes Endometrial Cancer Cells to Progestin.PLoS One. 2012;7(7):e41593. Epub 2012 Jul 24.
Progestin resistance is a major obstacle to treating early stage, well-differentiated endometrial cancer as well as recurrent endometrial cancer. The mechanism behind the suboptimal response to progestin is not well understood. The PTEN tumor suppressor gene is frequently mutated in type I endometrial cancers and this mutation results in hyperactivation of the PI3K/AKT pathway. We hypothesized that increased activation of AKT promotes an inadequate response to progestins in endometrial cancer cells. Ishikawa cells stably transfected with progesterone receptor B (PRB23 cells) were treated with the AKT inhibitor, MK-2206, which effectively decreased levels of p(Ser473)-AKT in a dose-dependent (10 nM to 1 uM) and time-dependent manner (0.5 h to 24 h). MK-2206 inhibited levels of p(Thr308)-AKT and a downstream target, p(Thr246)-PRAS40, but did not change levels of p(Thr202/Tyr204)ERK or p(Thr13/Tyr185)SAPK/JNK, demonstrating specificity of MK-2206 for AKT. Additionally, MK-2206 treatment of PRB23 cells resulted in a significant increase in levels of progesterone receptor B (PRB) protein. Microarray analysis of PRB23 cells identified PDK4 as the most highly upregulated gene among 70 upregulated genes in response to R5020. Inhibition of AKT further upregulated progestin-mediated expression of PDK4 but did not affect another progestin-responsive gene, SGK1. Treatment of PRB23 cells with R5020 and MK-2206 independently decreased viability of cells while the combination of R5020 and MK-2206 caused the greatest decrease in cell viability. Furthermore, mice with xenografted tumors treated with MK-2206 alone or with progesterone alone exhibited modest reductions in their tumor volume. The largest decrease in tumor size was observed in the mice treated with both MK-2206 and progesterone; these tumors exhibited the least proliferation (Ki67) and the most apoptosis (cleaved caspase-3) of all the treatment groups. In summary, inhibition of AKT stabilizes the Progesterone Receptor B and augments progesterone response in endometrial cancer cells that have hyperactivated AKT.
4 . Sangai T, Akcakanat A, Chen H, Tarco E, Wu Y, Do KA, Miller TW, Arteaga CL, Mills GB, Gonzalez-Angulo AM, Meric-Bernstam F.Biomarkers of Response to Akt Inhibitor MK-2206 in Breast Cancer.Clin Cancer Res. 2012 Aug 29.
PURPOSE: We tested the hypothesis that allosteric Akt inhibitor MK-2206 inhibits tumor growth, and that PTEN/PIK3CA mutations confer MK-2206 sensitivity. EXPERIMENTAL DESIGN: MK-2206 effects on cell signaling were assessed in vitro and in vivo. Its antitumor efficacy was assessed in vitro in a panel of cancer cell lines with differing PIK3CA and PTEN status. Its in vivo efficacy was tested as a single agent and in combination with paclitaxel. RESULTS: MK-2206 inhibited Akt signaling and cell cycle progression, and increased apoptosis in a dose-dependent manner in breast cancer cell lines. Cell lines with PTEN or PIK3CA mutations were significantly more sensitive to MK-2206, however, several lines with PTEN/PIK3CA mutations were MK-2206-resistant. Small interfering RNA (siRNA) knockdown of PTEN in breast cancer cells increased Akt phosphorylation concordant with increased MK-2206 sensitivity. Stable transfection of PIK3CA E545K or H1047R mutant plasmids into normal-like MCF10A breast cells enhanced MK-2206 sensitivity. Cell lines that were less sensitive to MK-2206 had lower ratios of Akt1/Akt2 and had less growth inhibition with Akt siRNA knockdown. In PTEN-mutant ZR75-1 breast cancer xenografts, MK-2206 treatment inhibited Akt signaling, cell proliferation, and tumor growth. In vitro, MK-2206 showed a synergistic interaction with paclitaxel in MK-2206-sensitive cell lines, and this combination had significantly greater antitumor efficacy than either agent alone in vivo.
5 . Morphy, Richard. Selectively Nonselective Kinase Inhibition: Striking the Right Balance. Journal of Medicinal Chemistry (2010), 53(4), 1413-1437.
Tsichlis et al microRNAs regulating Akt kinase isoenzyme levels and their use in diagnosis and prognosis of cancer and in screening for anti-cancer agents. PCT Int. Appl. (2010), 123 pp....